CA2016517C - Solid state electrochemical cell having microroughened current collector - Google Patents
Solid state electrochemical cell having microroughened current collectorInfo
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- CA2016517C CA2016517C CA002016517A CA2016517A CA2016517C CA 2016517 C CA2016517 C CA 2016517C CA 002016517 A CA002016517 A CA 002016517A CA 2016517 A CA2016517 A CA 2016517A CA 2016517 C CA2016517 C CA 2016517C
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- Prior art keywords
- layer
- current collector
- metal
- cathode
- cell
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Classifications
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/052—Li-accumulators
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
- H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
- H01M10/0565—Polymeric materials, e.g. gel-type or solid-type
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/64—Carriers or collectors
Abstract
A solid state laminar electrochemical cell comprising:
an alkali metal anode layer;
a solid ionically conductive electrolyte layer;
a cathode composition layer; and a current collector;
wherein said electrolyte layer is interposed between said alkali metal anode layer and said cathode layer and said cathode layer is interposed between said electrolyte layer and said current collector, the surface of said current collector which contacts said electrolyte layer being microroughened to enable the cathode layer to tightly adhere to said current collector is disclosed.
an alkali metal anode layer;
a solid ionically conductive electrolyte layer;
a cathode composition layer; and a current collector;
wherein said electrolyte layer is interposed between said alkali metal anode layer and said cathode layer and said cathode layer is interposed between said electrolyte layer and said current collector, the surface of said current collector which contacts said electrolyte layer being microroughened to enable the cathode layer to tightly adhere to said current collector is disclosed.
Description
20~ ~5~7 SOLID STATE ~LECTROCHEMICAL CELL
HAVING MICROROUGHENED CURRENT COLLECTOR
~ackqround of the Invention 1. Field of the Invention The present invention relates to the manufacture of a solid state electrochemical cell, and more particularly, a solid state cell having a lithium anode, electrolyte, cathode and current collector, wherein the adhesion of the cathode to the current collector is improved by microroughening the surface of the current collector which contacts the cathode.
HAVING MICROROUGHENED CURRENT COLLECTOR
~ackqround of the Invention 1. Field of the Invention The present invention relates to the manufacture of a solid state electrochemical cell, and more particularly, a solid state cell having a lithium anode, electrolyte, cathode and current collector, wherein the adhesion of the cathode to the current collector is improved by microroughening the surface of the current collector which contacts the cathode.
2. Description of the Prior Art Solid state electrochemical devic~s are the subject of intense investigation and development. They are described extensively in the patent literature. See, for example, U.S. Patents 4,303,748 to Armand; 4,589,197 to North; 4,547,440 to Hooper et al.; and 4,228,226 to Christiansen. These cells are typically constructed of an alkali metal foil anode, typically a lithium foil, an ionically conducting polymeric electrolyte, a finely divided transition metal oxide cathode, and a cathode current collector which is attac~e~ to the face of the cathode not contacting the electrolyte. The current collector usually employed is a sheet of metal foil such as aluminum, nic~el, or stainless steel.
Although the above described cells have presented a viable option to older, more traditional secondary type discharge cells, the rechargeability and i a~a~ce of the 40002-1030 -2- 2 0 1 6 ~ 17 cells have not achieved optimal performance. Part of the problem lies in the failure of the cathode material to form a good electric contact with the current collector. Failure of the cathode material making a good electrical contact with the current collector leads to an overall increase in cell impedance. This in turn, makes it difficult to recharge the cell.
In theory, optimal performance occurs if the cathode material is in intimate contact with the cathode current collector, and wherein the cathode current collector has a high surface area to enable uniform contact between the cathode material and the collector. Attempts have been made in the art to increase both the adherence of the cathode material to the current collector, and to increase the surface area of the current collector. However, no such attempts have been made in the field of solid state alkali metal anode cells.
For example, U.S. Patent Nos. 4,751,157 and 4,751,158 to Uchiyama et al. disclose cathode materials for use in lithium electrochemical cells. The cathode material comprises a mixed metal oxide as an active material, along with a conductive diluent and a b$nder which is pressed into electrodes on a nickel screen and sintered under vacuum.
The cathode materials are used in cells which contain a liquid electrolyte, and ~ore particularly, those which contain LiAs~6 in an aprotic solvent, such as methyl formate.
U.S. Patent No. 4,416,915 to Palmer et al.
discloses a chalcogenide cathode made by applying a slurry of a mixture containing at least one intercalatable layered transition metal chalcoqenide cathode active material, a conductivity enh~ncing agent and a bin~ing agent in a vehicle to a high porosity current collector substrate, for example, foamed metals and glasses which are 97% to 90%
4000?-1030 -1-20~6~17 porous with 10 to 1000 ~ores per square inch and adhering the cathode material to the substrate. The cathode material is utilized in a non-aqueous lithium cell having an electrolyte comprising an electrolyte-solvent mixture.
U.S. Patent No. 4,560,632 to Alberto discloses a molded porous cathode collector for use in non-aqueous cells. the collector includes a particulate carbonaceous conductive material bonded with a suitable binder, and having on its surface a coating of a vinyl polymer film to 10 improve its mechanical strength and handling characteristics. The cathode collector is used in association with liquid cathode materials.
U.S. Patent No. 4,~89,475 to Kleiner et al.
discloses electrical devices which include two electrodes 15 and a conductive polymer element located between the two electrodes. One of the electrodes is a metal electrode whose surface which contacts the conductive polymer is roughened or otherwise treated to improve its adhesion to the conductive polymer. The conductive polymers exhibit 20 positive temperature coefficient behavior so that the electrical device can be used in heaters and circuit protection devices.
In the field of solid state lithium cells, U.S.
Patent No. 4,735,875 to Anderman et al. discloses a cell 25 wherein a cathode material which takes the form of a microporous sheet containing polyethylene, an electrically conductive and electrochemically active particulate material and a plasticizer is laminated to a current collector such as a screen, grid, expanded metal, woven or non-woven fabric 30 formed from efficient electron conductive materials such as carbon, or metal such as copper, aluminum, nickel, steel, lead or iron.
Accordingly, there exists a need in the art for2a0 solid state alkali metal cell wherein a highly uniform electrical contact between the cathode material and cathode current collector is maintained during operation and recharging of the cell.
SummarY of the Invention In accordance with the present invention, a solid state alkali metal anode primary or secondary cell having significant improvements in cell impedance and, in turn, rechargeability and high current discharge (power) is provided. The cell is particularly characterized by the maintenance of a tightly adherent contact between the cathode and cathode current collector of the cell.
In accordance with one embodiment, the invention comprises a solid state laminar electrochemical cell comprising:
an alkali metal anode layer;
a solid ionically conductive electrolyte layer;
a cathode composition layer; and a current collector;
wherein said electrolyte layer is interposed between said alkali metal anode layer and said cathode layer and said cathode layer is interposed between said electrolyte layer and said current collector, the surface of said current collector which contacts said electrolyte layer being microrou~hened to enable the ca~hode layer to tightly adhere to said current collec~or.
In a particular embodiment, the alkali metal anode layer comprises a lithium foil, a lithium coated metal foil or a lithium alloy. The preferred electrolyte is a single-phase solid solution of an ionizable alkali metal salt, a solvent for the salt, and a polymer which has been polymerized by exposure to actinic radiation. The cathode 2016~17 composition preferably includes V6O13, electrically-conductive carbon particles and the a~ove-described ionically-conductive electrolyte.
The current collector is electrically conductive and is characterized by its surface which contacts the cathode being microroughened to enable better adherence of the cathode to the current collector. The microroughening of the surface can be accomplished by a number of methods.
For example, the current collector can take the form of a metal foil substrate having the same or different metal particles electrodeposited onto its upper surface. The external surfaces of the metal particles form the microroughened surface. Alternatively, the current collector can ta~e the form of a polymeric film having an electrically conductive material coated on its upper surface. The electrically conductive material, which takes the form of a metal or an electroconductive ink is discontinuously coated onto the film. The surface discontinituities form the microroughene~ surface. The improved adherence of the cathode composition to the current collector reduces the impedance of the overall cell, thereby improving perfoL -nce~ particularly during recharging.
In accordance with another ~ ~o~i ent of the present invention, a current collector for contacting the cathode layer of a solid state electrochemical laminar cell is provided. The collector comprises a metal foil, the surface of the metal foll which is to contact the cathode layer being microrou~hene~.
In practice, the foil is preferably a nic~el or copper foil and microroughening is accomplished by electrodepositing metal particles, typically nic~el particles onto the metal foil.
In still another embodiment, a current collector for contacting the cathode layer of a solid state electrochemical 1~ in~r cell is provided. The collector comprises a polymeric substrate having an electrically 2 0 16 ~ 17 conductive material deposited on the surface of the substrate which is to contact the cathode layer. The substrate preferably comprises a polyethylene terephthalate film and the material typically comprises one or more electrodeposited metals or an electroconductive ink. ~or example, the current collector can take the form of a plastic film having a first layer of a vapor deposited copper film and a second layer of electrodeposited nickel particles, o~ercoating the first copper layer. The chief advantage of this collector is that it can be manufactured with a minimal thickness.
Accordingly, it is an object of the present invention to provide a solid state electrochemical cell having an overall low impedance and improved rechargability.
A further object of the present invention is to provide a current collector for use in a solid state electrochemical laminar cell which is designed to have improved adherence to a cathode composition.
These, as well as other objects will become readily apparent to those skilled in the art as reference is made to the following drawings and detailed description of the preferred embodiment.
Brief Description of the Drawings Fig. 1 is a side cut-away view of a cell embodying the tea~hin~s of the instant invention.
Fig. 2 is a side view of a current collector embodying the teachings of the instant invention.
Fig. 3 is an electron microscope photograph top view of a nickel foil having electrodeposited thereon nickel particles.
Fig. 4 is an electron microscope photograph side view of a copper foil having electrodeposited thereon an irre~ular laye~ of nickel.
Fig. 5 is a side view of an alternate current 2 016 ~ 17 collector embodying the teachings of the instant invent~on.
Fig. 6 is an electron microscope photograph side view of a polyethylene terephthalate film overcoated with a 5 vapor deposited layer of copper which is overcoated with an electrochemically deposited layer of nickel.
Detailed Description of the Preferred Embodiment While describing the preferred embodiment, certain terminology will be utilized for the sake of clarity. It is 10 intended that such terminology include not only the recited embodiment, but all technical equivalents which perform substantially the same function, in substantially the same way to achieve substantially the same result.
A laminar solid state cell produced in accordance 15 with one embodiment of the present invention is shown in Fig. 1 and is represented by element 10. Cell 10 includes current collector layer 12, cathode composition layer 14, electrolyte composition layer 16 and alkali metal anode ' layer 18. Cell 10 also includes protective covering 20 which functions to prevent water and air from contacting the reactive layers of the cell.
Cell 10 is preferably a laminar thin cell type including a lithium anode. Laminar thin-cell batteries containing lithium anoAes are known in the art, and it will be appreciated that the cell can include various construct~ons such as bi-faced or bi-polar cell designs.
~xamples of cell co~structions include a "jelly rolln or a fan folded laminate strip design, both of which are illustrated in U.S. Patent Application Serial No. 238,071 filed August 30, 1988, which is hereby incorporated by reference.
Referring now to Fig. 2, the current collector, designated by element 11 is shown in greater detail.
Collector 11 includes substrate 12, preferably a metal foil 40002-lO~0 -8-2016-) 17 having a microroughened surface 13. Presence of microroughened surface 13 enables better adherence of the cathode composition to the current collector.
Substrate 12 may be selected from any number of electrically conductive materials, typically metals.
Examples of substrate materials include carbon, copper, aluminum, nic~el, steel, lead and iron and combinations thereof. In practice, the thickness of substrate 12 typically ranges from about 5 microns to about 25 microns and should be as thin as practicable.
The microroughened surface 13 can be prepared in a number of different ways. The preferred method is electrodeposition of metal particles, preferably copper or nickel particles onto substrate 12, the microroughened surface being the surface which is exposed to the cathode composition. For example, electrodeposited foils, particularly copper and nickel foils, are preferred for use in this invention. It is also possible to use other processes which result in a similar degree of roughness, e.g., irregularities which protrude from the surface by a distance of at least 0.03 microns, preferably at least 0.1 microns, particularly 0.1 to 100 microns, and which have at least one dimension parallel to the surface which is at most 500 microns, preferably at most 100 microns, particularly at most 10 microns, and which is preferably at least 0.03 micron, particularly at least 0.1 micron. The irregularities can ble of the same shape as those produced by electrodeposition, e.g., generally spherical nodules protruding from the surface, or they can be of a different shape. Such processes can create the microrough surface by removal of material from a smooth surface, e.g., by etching, by chemical reaction with a smooth surface, e.g., by galvanic deposition, or by deposition of a microrough layer of the same or a different m3terial on a smooth surface. A
2nl6~7 smooth foil can be treated by contact e.g. rolling or pressing with a patterned surface to generate a microroughness. The microrough surface can if desired be treated to change its chemical characteristics. For example, an electrodeposited metal foil can be passivated i.e. rendered inactive or less chemically reactive, by an appropriate treatment, e.g., one which provides a coating thereon of a water-stable oxide, especially a zinc-nic~el or nickel treatment of an electrodeposited copper foil.
Referring to Figure 3, an electron microscope top view of a nickel foil 12 with nic~el particles 13 electrodeposited thereon is shown. The surface characteristics of the electrodeposited particles 13 provide the microroughened surface to enable better adhesion to the cathode composition.
Referring to Figure 4, an electron microscope side view of an alternative metal coated metal foil current collector is shown. The collector llA comprises a copper foil 12A overcoated with a discontinuous layer of nickel metal 13A. The surface of the nic~el metal 13A is discontinuous to provide better adhesion to the cathode composition.
Referring bac~ to Fig. 1, alkali metal anode layer 18 may take the form of a lithium foil, a lithium coated foil such as nickel or copper foil having a layer of lithium deposited on its surface or a lithium alloy. Lithium is a preferred anode material because it is very electropositive and light in weight, However, other alkali metal materials, such as sodium, may be practiced within the scope of the present invention.
Electrolyte layer 16, which is ionically but not electrically conductive, takes the form of a solid material and is laminated to the alkali metal anode layer 18 and the cathode layer 14.
2016~17 The preferred electrolytes are solutions of an ionizable al~all metal salt or an alkaline earth salt,an aprotic solvent and a polymerl2able compound. Still more preferred are solutions of an alkali metal salt, a liquid, monomeric or prepolymeric radiatlon or thermally polymerizable compound and a radiation or thermally inert ionically conducting liquid.
Polymerizable compounds useful in the electrolyte composition may yield either a conductive or nonconductive polymer. Compounds which yield a conductive polymer contain a heteroatom capable of forming donor-acceptor bonds with the alkali metal cation. Useful polymerizable compounds are described next.
Polyethylenically unsaturated monomeric or prepolymonomeric materials useful in the present invention are preferably co~pounds having at least one, and more preferably a plurality, of heteroatoms (particularly oxygen and/or nitrogen atoms) capable of forming donor acceptor bonds with an al~ali metal cation and are terminated by polymerizable moieties. These compounds yield a conductive supportive matrix. More specifically they are preferably low molecular weight oligomers of the formulae (I)-(III) below A -(-CH2-~CH-O-)~n A (I) R
A -(-cH2-cH2-l-)-n A (II) R
A -t-CH2-~N-CH2-) n A (III) 40002-lO30 2 ~ 1 7 where n is about 3 to 50 and R is hydrogen or a C1-C3 alkyl group which is terminated by ethylenically unsaturated moieties or glycidyl moieties represented by A. A
particularly useful group of compounds is obtained by reacting a polyethylene glycol with acrylic or methacrylic acid. Polyethylene glycol diacrylate is a particularly preferred polymer. To provide additional structural integrity, triacrylate prepolymers may be added.
ereferably~ the radiation or thermally inert ionically conductive liquids have a boiling point greater than 80 C. Examples of these liquids include -butyrolactone, propylene carbonate, 1,3-dioxolane and 2-methyltetrahydrofuran. Less polar solvents having heteroatoms capable of bonding alkali metal cations are also useful. Polyethylene glycol dimethyl ether (PEGDME) is one such example. Glymes such as tetraglyme, hexaglyme, and heptaglyme are also desirable solvents. Propylene carbonate is a preferred solvent.
As to the ionizable salt, formula MX, this is not limiting at all, and is the type in which:
M+=Li+, Na+, K~, Ca2+, Mg2+, NH4+
X-=I-, C104-, BF4-, AsF~-, CF3SO3-, CF3CO3-, PF6-sl2Hl22-~ B1oClo2-, B~4-,~ designating C6Hs, or an alkyl or an aryl chain.
To produce a solid electrolyte material, the solution of the ionizable salt and inert ionically conductive liquid is mixed with the curable composition and the mixture is cured by exposure to actinic radiation, preferably electron beam or ultraviolet radiation or by heating if a thermally curable system is utilized. If ultraviolet radiation is used for curing, an ultraviolet photoinitiator may be added to the composition. Similarly if a thermally curable composition is selected, a thermal 20~17 lnitiator should be present in the composition. ~xamples of thermally curable compositions are disclosed in U.S. Patent No. 4,792,504, which is hereby incorporated by reference.
Alternatively, the electrolyte can ta~e the form of a solid solution of an alkali or al~aline earth salt in a curable polymerizable compound. In still another embodiment, the solid solution may include a plasticizer or liquid electrolyte in addition to the solid solution.
The cathode composition layer 14 includes a cathode material which is coated on the microroughened 13 surface of the current collector 12.
Cathode compositions are known in the art.
Typically they comprise an intercalation compound, an ionically conductive solid polymer electrolyte containing solution of an alkali metal salt or alkaline earth salt as defined above, and an electrically conductive filler. A
typical formulation may contain about 25 to about 70 parts by weight of intercalation compound, about 2 to about 15 parts of an electrically conductive filler, and about 15 to about 75 parts of the ionically conductive electrolyte.
The following compounds have been taught in the art for use as intercalation compounds: V6O13, MoO2, MnO2, V2O5~ TiS2~ MoS3~ Cr3~6~ LiXV3Og~ V3O8~ VS2, NbSe2, FeOCl, CrOBr, TiNCl, ZrNCl, HfNBr, FeS, NiS, Co0, Cu0 and WO2.
V6O13 is particularly preferred. For use as an electrically conductive filler, carbon may be used.
In addition to providing a matrix for containing the alkali metal salt, the ionically conductive polymer additionally functions as a binder material to enable the cathode composition to adhere to the collector substrate.
~ecause of its adhesive qualities, acrylated polyethylene oxide is the preferred ionically conductive polymer. For use as an additional adhesive, acrylated polyesters may be --selected.
The process for producing cell 10 is as follows.
Because the cell produced utilizes an alkali metal anode layer, usually a lithium anode layer, it is necessary to manufacture the cell in a water (humidity) free environment.
Lithium is extremely reactive with water and if reacted, a passivation layer can form on the surface of the anode layer, reducing the efficiency of the layer, and increasing cell impedance. Accordingly, it is particularly desirable to manufacture the cell in an environment having a relative humidity at room temperature of less than 2% (less than 300 ppm water). An environment containing between 1 ppm and 50 ppm water produces a particularly efficient cell.
Cathode composition 14 as defined above is coated onto the microroughened surface of current collector 12.
Cathode composition 14 is paste-like in consistency.
Coating may be accomplished using conventional coating techniques such as doctor blade or coating an extrusion method. In practice, the optimum thickness ranges between about 25 and about 250 microns. In order to obtain a one-hour discharge with 75-100% utilization of the cathode composition, the layer thickness ranges between 50 and 100 microns in thickness. Where a faster discharge rate is desired, a lower thickness may be selected. ~onversely, if a slower discharge rate is desired, a thic~er layer may be provided. In practice, the cathode composition layer has an impedance less than 50 ohms/cm2.
After cathode composition 14 has been coated onto current collector 12, the top surface of the cathode layer is optionally rolled by utilizinq a non-stic~ pressure roller such as a PTFE roller. Alternatively, if the cathode composition stic~s to the surface of the roller, a non-stic~
release liner, not pictured, may be placed onto the upper surface, the roller can traverse the length of the release liner, and the release liner can then be removed. Rolling 40002-1030 -14- 2016~17 the upper surface of the cathode layer benefits in that it improves adherence between cathode composition 14 and current collector 12 and produces a smoother surface which enables a very thin electrolyte layer to be coated thereon.
As a result of the surface rolling, the open circuit voltage discharge associated with cathode composition 14 is significantly reduced as compared to a cell whose cathode does not have a rolled surface. Accordingly, the overall cell efficiency is improved.
The utilization of microroughened surface 13 of the current coilector 12 along with the optional pressure rolling step following the coating of cathode composition 14 onto current collector 12 enables a tightly adherent contact to occur between the respective materials. This, in turn, reduces imre~nce at the collector/cathode composition interface. The impedance at the interface is typically less than 10 ohms/cm2 and, in the preferred embodiment, less than 5 ohms/cm2.
Electrolyte layer 16 is coated as a thin film onto the cathode composition layer 14. The electrolyte can be extruded and coated in a very thin layer, typically ranging from about 5 microns to about 25 microns. The ability to coat in a thin layer is in large part due to the continuous surface of cathode composition. When electrolyte 16 is coated onto cathode 14, it is coated in an uncured liquid state. As is readily understood, electrolyte layer 16 must completely coat cat~ode composition layer 14 to prevent the intercalation compound and electrically conductive filler from protruding through electrolyte layer 16. The thickness of electrolyte layer 16 need only be thic~ enough to completely coat the upper surface of the cathode composition.
Once electrolyte layer 16 has been coated onto cathode composition 14, the asse0bly is partially or totally 40002-1030 -15- 2 0 1 6 ~ 1 7 cured by radiation or thermal means. In practice, exposure of the assembly to an electron beam operating at a power of 3 to 9 Mrad is particularly preferred. Alternatively an ultraviolet or thermal source may be selected. If an ultraviolet source is selected, the monomer preferabLy includes an ultraviolet initiator of the type commonly known in the art such as thioxanthone initiators. If a thermal source is selected, the monomer preferably includes a thermal initiator of the type commonly known in the art such as those disclosed in U.S. Patent No. 4,792,504 to Scbwab et al. Curing the cathode composition and the electrolyte polymerizes and crosslinks and thereby solidifies the monomeric material by conversion ~o a polymeric form.
A partial curinq step (as opposed to ~ull curing) may be particularly desirable as this enables the electrolyte layer 16 to remain somewhat tac~y. This enables better adherence between the electrolyte and the anode layer, when coated.
After partial or total curing of cathode composition 14 and electrolyte 16, alkali metal anode layer 18 is applied to electrolyte layer 16. Although not pictured, a thin polymeric material such as a porous polypropylene sheet may be interposed between the anode and the electrolyte to ensure that the anode does not contact the cathode layer, particularly at the outer edges of the respective layers. Use of the polymeric sheet is optional.
After anode layer 18 is coated onto electrolyte 16, the entire assembly is optionally passed through pressure rollers. The pressure rolling step aids in the adhesion of the layers to each other, thereby reducing interfacial il o~ance between component layers.
If the cathode composition 16 and electrolyte 14 have not been completely cured, the entire assembly is again cured by exposure to actinic radiation, preferably electron 40002-1030 -16- 2 0 1 ~ .~ 1 7 beam radiation or by thermally curing. This step functions to solidify the cathode composition and electrolyte layers, thereby producing a solid state cell.
Once the current collector, cathode composition, electrolyte composition and anode composition have been assembled, electrodes are attached to the anode and current collector layers by means known in the art. The assembly is then inserted into an air and water impermeable protective material 20 and the edges of the protective material are sealed, preferably by heat sealing around edges of the cell components. Sealing preferably occurs under vacuum conditions to enable the protective material to form a tightly adherent seal around the component layers and electrodes such that the only external access to the component layers is via the electrodes.
Examples of the heat sealable gas and water impermeable protective materials include a multi-layered material having an interior heat sealable layer comprising ethylene acrylic acid, an intermediate barrier layer comprising aluminum foil, and an exterior layer of polyethylene terephthalate. Other heat sealable protective materials known in the art can be used in accordance with the present invention. The protective materials should be as thin as possible to minimize the overall thickness of the cell. Commercially available heat sealable materials of ~he types described above can have an overall thickness of less than 200 microns.
Once the components have been inserted and sealed in the protective ~aterial, the cell is available for use by simply connecting the electrodes to the device to be powered. When utilizing a single lithium anode cell, the cell generates a voltage of approxim~tely 2.7 volts and a current flow exceeding 50 milliamps/cm2.
Referring now to Fig. 5 an alternative current collector is shown and designated as l00. Collector 100 includes polymeric substrate 102 having coated thereon a layer of an electrically conductive material 104.
Optionally overcoated on material 104 is another layer of an electrically conductive material 106. Substrate 102 may be selected from polymeric film materials including polyethylene, polyethylene terephthalate and polyvinyl chloride. The thickness of film 102 is extremely thin, with 10' thickness of less than 5 microns and even about 1 micron possible. This enables the manufacture of very thin current collectors, and hence, very thin l~ in~r cells.
Electrically conductive materials 104 or 106 may be any of the materials as discussed with respect to Fig. 2.
Examples of such materials may include copper, carbon, aluminum, nickel, steel, lead and iron and combinations thereof.
Alternatively, examples of other electrically conductive materials may include electrically conductive inks. Such inks are known in the art and are typically used for screen printing, manufacture of membrane switches, EL
lamps and displays, and flexible circuits. Examples of silver filled and indium oxide-filled electrically conductive inks are manufactured by Zymet Inc. of East Hanover, New Jersey. The inks are applied onto the polymeric film in a patterned form such as a grid, mesh, spiral, and the like. Depending on the thickness of the ink layer, an extremely thin current collector can be produced.
Referring to Fig. 6, an electron microscope side view photograph of a current collector manufactured in accordance with the present invention is shown. Collector 100A includes polyethylene terephthalate film 102A
overcoated with a vapor deposited first layer of copper 104A
which is overcoated with an electrodeposited layer of nickel particles 106A. The overall thickness of this collector is about 1 to 5 microns.
The invention is further explained in the following non limiting examples.
40002-1030 -18- 2016~7 Comparative ExamPle 1 A cell was produced by first forming a cathode mixture including 45% by weight V6O13, 4% carbon and 51% of an electrolyte including 70% propylene carbonate, 3%
polyethylene oxide, 6% LiCF3S03 and 21% of a radiation curable acrylate. This mixture was coated onto a 15 micron thick solid nickel foil current collector to a thickness of about 75 microns having a surface area of about 32cm2. The above defined electrolyte was then coated onto the cathode to a thickness of about 50 microns. A 100 micron thick lithium foil was then laminated onto the electrolyte and the entire structure was subjected to electron beam radiation to cure the cathode and electrolyte. The initial cell impedance at 1 Hz was measured to be about 110 ohms.
Example 2 A cell having the identical cathode, electrolyte and anode of Comparative Example 1 was produced by using a 35 micron thick nickel foil current collector having a surface area of about 32cm2 which was etched to provide a roughened surface. The measured impedance at 1 Hz was 12 ohms.
ComParative Example 3 A cell was prepared identical to the cell of Cs ~rative Example 1 with the exception that the cathode contained 53% V6O13, 8~ carbon and 39% electrolyte. The measured cell impedance at 1 Hz was 150 ohms.
Example 4 A cell having the identical cathode, electrolyte and anode of Comparative Example 3 was produced using the current collector of Example 2. The measured impedance at 1 Hz was 5 ohms.
2016~17 Example 5 The cell of Comparative Example 3 was discharged at 200 microamperes/cm2 at room temperature to lower the voltage from 3 V to l.S V. The discharge time was 15 hours.
Example 6 The experiment of Example 5 was repeated using the cell of Example 4. The discharge time was 17.5 hours.
Example 7 In an inert, nitrogen environment, a cathode composition is prepared by grinding 300 parts of V6O13 for 24 to ~8 hours in the presence of an equal amount of tetrahydrofuran in a one liter ball mill using 1.25 cm diameter ceramic balls. After grinding, the average particle size of V6O13 is about 1.5 microns. The slurry is transferred to an airtight mixer and 46.2 parts of predried carbon are added to the mixer to produce a slurry having a weight ratio of V6O13 to C of about 6.5 to 1. The mixture is stirred at low speed (20 rpm) under vacuum and heat, until the tetrahydrofuran is evaporated. The overall water content of the mixture is less than 100 ppm. 3 parts of polyethylene oxide ~PEO) having a molecular weight greater than 100,000 is added to the V6O13/C powder mixture. The mixture is stirred for about 10 to 20 minutes to adequately disperse the polyethylen~e oxide. ~ ~ , Propylene carbonate (PC), polyethylene glycol ~ - ~yl ~t~r ~ ~C/~
(PEG ~ ), and trimethylolpropane ethoxylated triacrylate (TMPEOTA) are added to the mixture to produce a mixture having the following components:
component Percent (weiqht) V6~13 45 PEO
PEGDA 8.5 TMPEOTA 1.5 2016~ 17 The mixture temperature is increased to 65 C and the mixture is stirred at low speed for 20 minutes. The speed of the mixer is increased to 75 rpm and the mixture is stirred for 2 to 3 additional hours.
The mixture is then coated onto a 5cm x 20cm x 25 micron high surface treated nickel foil available from Eukuda Metal Foil & Powder Co. Ltd. of Kyoto, Japan by utilizing a doctor blade technique at 50-60'C in a completely inert (nitrogen) environment containing less than 25 ppm water. The thickness of the cathode --layer is 75 microns and the cathode layer is then covered with a stainless steel foil. A 2 inch diameter, 10 inch long stainless steel roller is placed on top of the foil and the roller is rolled along the length of the foil at a pressure of 5-10 kg/cm2 to improve adherence of the cathode layer to the current collector. The assembly is then irradiated with a 3 Mrad dose of radiation by utilizing an electron beam source to cure the cathode layer. The foil is then peeled off of the cathode layer.
The impedance of the cathode is less than 50 ohm/cm2.
An electrolyte is prepared by mixing together the following components in the following weight fractions:
component ~ercent (weight) LiAsF6 18 PEO 2.5 25 eEGDA 9.2 TMPEOTA 2.3 The overall water concentration of the electrolyte is less than 50 ppm. The electrolyte is coated onto the cathode layer by using a doctor blade at room temperature to a thic~ness of about 25 microns. The electrolyte is then irradiated with a 3 Mrad dose of radiation from an electron beam source. The impedance of the electrolyte layer is about 0.8 ohm/cm2.
2~1fi-)17 A 4cm x 12.5cm x 125 micron thick lithium s~rip (lithium metal/battery grade) available from Lithco of ~essemer City, NC
is applied tO one end of the electrolyte layer and the lithium strip is adhered to the layer by applying pressure from a 2 inch diameter, 10 inch long roller at 5-10 kg/cm2 across the entire lithium surface. The opposite end of the electrolyte/cathode/current collector assembly is folded over the anode layer to form a bifaced cell. Copper tabs were spot welded to the current collector and pressure rolled onto the lithium foil to form electrodes for connection to a device.
The physical and mechanical properties of the produced battery were as follows:
property value surface area 100 cm2 volume 2 cm3 capacity 250 mAh average voltage 2.4 V
discharge time (50 mA drain) S hours - discharge time (250 mA drain) 0.5 hours discharge time (10 A pulses) 1.5 minutes energy density 300 wh/l overall impedance 150 ohm/cm2 Having described the invention in detail and by reference to preferred embodiments thereof, it will be apparent that modifications and variations are possible without departing from the scope of the invention defined in the appended claims.
What is claimed is:
Although the above described cells have presented a viable option to older, more traditional secondary type discharge cells, the rechargeability and i a~a~ce of the 40002-1030 -2- 2 0 1 6 ~ 17 cells have not achieved optimal performance. Part of the problem lies in the failure of the cathode material to form a good electric contact with the current collector. Failure of the cathode material making a good electrical contact with the current collector leads to an overall increase in cell impedance. This in turn, makes it difficult to recharge the cell.
In theory, optimal performance occurs if the cathode material is in intimate contact with the cathode current collector, and wherein the cathode current collector has a high surface area to enable uniform contact between the cathode material and the collector. Attempts have been made in the art to increase both the adherence of the cathode material to the current collector, and to increase the surface area of the current collector. However, no such attempts have been made in the field of solid state alkali metal anode cells.
For example, U.S. Patent Nos. 4,751,157 and 4,751,158 to Uchiyama et al. disclose cathode materials for use in lithium electrochemical cells. The cathode material comprises a mixed metal oxide as an active material, along with a conductive diluent and a b$nder which is pressed into electrodes on a nickel screen and sintered under vacuum.
The cathode materials are used in cells which contain a liquid electrolyte, and ~ore particularly, those which contain LiAs~6 in an aprotic solvent, such as methyl formate.
U.S. Patent No. 4,416,915 to Palmer et al.
discloses a chalcogenide cathode made by applying a slurry of a mixture containing at least one intercalatable layered transition metal chalcoqenide cathode active material, a conductivity enh~ncing agent and a bin~ing agent in a vehicle to a high porosity current collector substrate, for example, foamed metals and glasses which are 97% to 90%
4000?-1030 -1-20~6~17 porous with 10 to 1000 ~ores per square inch and adhering the cathode material to the substrate. The cathode material is utilized in a non-aqueous lithium cell having an electrolyte comprising an electrolyte-solvent mixture.
U.S. Patent No. 4,560,632 to Alberto discloses a molded porous cathode collector for use in non-aqueous cells. the collector includes a particulate carbonaceous conductive material bonded with a suitable binder, and having on its surface a coating of a vinyl polymer film to 10 improve its mechanical strength and handling characteristics. The cathode collector is used in association with liquid cathode materials.
U.S. Patent No. 4,~89,475 to Kleiner et al.
discloses electrical devices which include two electrodes 15 and a conductive polymer element located between the two electrodes. One of the electrodes is a metal electrode whose surface which contacts the conductive polymer is roughened or otherwise treated to improve its adhesion to the conductive polymer. The conductive polymers exhibit 20 positive temperature coefficient behavior so that the electrical device can be used in heaters and circuit protection devices.
In the field of solid state lithium cells, U.S.
Patent No. 4,735,875 to Anderman et al. discloses a cell 25 wherein a cathode material which takes the form of a microporous sheet containing polyethylene, an electrically conductive and electrochemically active particulate material and a plasticizer is laminated to a current collector such as a screen, grid, expanded metal, woven or non-woven fabric 30 formed from efficient electron conductive materials such as carbon, or metal such as copper, aluminum, nickel, steel, lead or iron.
Accordingly, there exists a need in the art for2a0 solid state alkali metal cell wherein a highly uniform electrical contact between the cathode material and cathode current collector is maintained during operation and recharging of the cell.
SummarY of the Invention In accordance with the present invention, a solid state alkali metal anode primary or secondary cell having significant improvements in cell impedance and, in turn, rechargeability and high current discharge (power) is provided. The cell is particularly characterized by the maintenance of a tightly adherent contact between the cathode and cathode current collector of the cell.
In accordance with one embodiment, the invention comprises a solid state laminar electrochemical cell comprising:
an alkali metal anode layer;
a solid ionically conductive electrolyte layer;
a cathode composition layer; and a current collector;
wherein said electrolyte layer is interposed between said alkali metal anode layer and said cathode layer and said cathode layer is interposed between said electrolyte layer and said current collector, the surface of said current collector which contacts said electrolyte layer being microrou~hened to enable the ca~hode layer to tightly adhere to said current collec~or.
In a particular embodiment, the alkali metal anode layer comprises a lithium foil, a lithium coated metal foil or a lithium alloy. The preferred electrolyte is a single-phase solid solution of an ionizable alkali metal salt, a solvent for the salt, and a polymer which has been polymerized by exposure to actinic radiation. The cathode 2016~17 composition preferably includes V6O13, electrically-conductive carbon particles and the a~ove-described ionically-conductive electrolyte.
The current collector is electrically conductive and is characterized by its surface which contacts the cathode being microroughened to enable better adherence of the cathode to the current collector. The microroughening of the surface can be accomplished by a number of methods.
For example, the current collector can take the form of a metal foil substrate having the same or different metal particles electrodeposited onto its upper surface. The external surfaces of the metal particles form the microroughened surface. Alternatively, the current collector can ta~e the form of a polymeric film having an electrically conductive material coated on its upper surface. The electrically conductive material, which takes the form of a metal or an electroconductive ink is discontinuously coated onto the film. The surface discontinituities form the microroughene~ surface. The improved adherence of the cathode composition to the current collector reduces the impedance of the overall cell, thereby improving perfoL -nce~ particularly during recharging.
In accordance with another ~ ~o~i ent of the present invention, a current collector for contacting the cathode layer of a solid state electrochemical laminar cell is provided. The collector comprises a metal foil, the surface of the metal foll which is to contact the cathode layer being microrou~hene~.
In practice, the foil is preferably a nic~el or copper foil and microroughening is accomplished by electrodepositing metal particles, typically nic~el particles onto the metal foil.
In still another embodiment, a current collector for contacting the cathode layer of a solid state electrochemical 1~ in~r cell is provided. The collector comprises a polymeric substrate having an electrically 2 0 16 ~ 17 conductive material deposited on the surface of the substrate which is to contact the cathode layer. The substrate preferably comprises a polyethylene terephthalate film and the material typically comprises one or more electrodeposited metals or an electroconductive ink. ~or example, the current collector can take the form of a plastic film having a first layer of a vapor deposited copper film and a second layer of electrodeposited nickel particles, o~ercoating the first copper layer. The chief advantage of this collector is that it can be manufactured with a minimal thickness.
Accordingly, it is an object of the present invention to provide a solid state electrochemical cell having an overall low impedance and improved rechargability.
A further object of the present invention is to provide a current collector for use in a solid state electrochemical laminar cell which is designed to have improved adherence to a cathode composition.
These, as well as other objects will become readily apparent to those skilled in the art as reference is made to the following drawings and detailed description of the preferred embodiment.
Brief Description of the Drawings Fig. 1 is a side cut-away view of a cell embodying the tea~hin~s of the instant invention.
Fig. 2 is a side view of a current collector embodying the teachings of the instant invention.
Fig. 3 is an electron microscope photograph top view of a nickel foil having electrodeposited thereon nickel particles.
Fig. 4 is an electron microscope photograph side view of a copper foil having electrodeposited thereon an irre~ular laye~ of nickel.
Fig. 5 is a side view of an alternate current 2 016 ~ 17 collector embodying the teachings of the instant invent~on.
Fig. 6 is an electron microscope photograph side view of a polyethylene terephthalate film overcoated with a 5 vapor deposited layer of copper which is overcoated with an electrochemically deposited layer of nickel.
Detailed Description of the Preferred Embodiment While describing the preferred embodiment, certain terminology will be utilized for the sake of clarity. It is 10 intended that such terminology include not only the recited embodiment, but all technical equivalents which perform substantially the same function, in substantially the same way to achieve substantially the same result.
A laminar solid state cell produced in accordance 15 with one embodiment of the present invention is shown in Fig. 1 and is represented by element 10. Cell 10 includes current collector layer 12, cathode composition layer 14, electrolyte composition layer 16 and alkali metal anode ' layer 18. Cell 10 also includes protective covering 20 which functions to prevent water and air from contacting the reactive layers of the cell.
Cell 10 is preferably a laminar thin cell type including a lithium anode. Laminar thin-cell batteries containing lithium anoAes are known in the art, and it will be appreciated that the cell can include various construct~ons such as bi-faced or bi-polar cell designs.
~xamples of cell co~structions include a "jelly rolln or a fan folded laminate strip design, both of which are illustrated in U.S. Patent Application Serial No. 238,071 filed August 30, 1988, which is hereby incorporated by reference.
Referring now to Fig. 2, the current collector, designated by element 11 is shown in greater detail.
Collector 11 includes substrate 12, preferably a metal foil 40002-lO~0 -8-2016-) 17 having a microroughened surface 13. Presence of microroughened surface 13 enables better adherence of the cathode composition to the current collector.
Substrate 12 may be selected from any number of electrically conductive materials, typically metals.
Examples of substrate materials include carbon, copper, aluminum, nic~el, steel, lead and iron and combinations thereof. In practice, the thickness of substrate 12 typically ranges from about 5 microns to about 25 microns and should be as thin as practicable.
The microroughened surface 13 can be prepared in a number of different ways. The preferred method is electrodeposition of metal particles, preferably copper or nickel particles onto substrate 12, the microroughened surface being the surface which is exposed to the cathode composition. For example, electrodeposited foils, particularly copper and nickel foils, are preferred for use in this invention. It is also possible to use other processes which result in a similar degree of roughness, e.g., irregularities which protrude from the surface by a distance of at least 0.03 microns, preferably at least 0.1 microns, particularly 0.1 to 100 microns, and which have at least one dimension parallel to the surface which is at most 500 microns, preferably at most 100 microns, particularly at most 10 microns, and which is preferably at least 0.03 micron, particularly at least 0.1 micron. The irregularities can ble of the same shape as those produced by electrodeposition, e.g., generally spherical nodules protruding from the surface, or they can be of a different shape. Such processes can create the microrough surface by removal of material from a smooth surface, e.g., by etching, by chemical reaction with a smooth surface, e.g., by galvanic deposition, or by deposition of a microrough layer of the same or a different m3terial on a smooth surface. A
2nl6~7 smooth foil can be treated by contact e.g. rolling or pressing with a patterned surface to generate a microroughness. The microrough surface can if desired be treated to change its chemical characteristics. For example, an electrodeposited metal foil can be passivated i.e. rendered inactive or less chemically reactive, by an appropriate treatment, e.g., one which provides a coating thereon of a water-stable oxide, especially a zinc-nic~el or nickel treatment of an electrodeposited copper foil.
Referring to Figure 3, an electron microscope top view of a nickel foil 12 with nic~el particles 13 electrodeposited thereon is shown. The surface characteristics of the electrodeposited particles 13 provide the microroughened surface to enable better adhesion to the cathode composition.
Referring to Figure 4, an electron microscope side view of an alternative metal coated metal foil current collector is shown. The collector llA comprises a copper foil 12A overcoated with a discontinuous layer of nickel metal 13A. The surface of the nic~el metal 13A is discontinuous to provide better adhesion to the cathode composition.
Referring bac~ to Fig. 1, alkali metal anode layer 18 may take the form of a lithium foil, a lithium coated foil such as nickel or copper foil having a layer of lithium deposited on its surface or a lithium alloy. Lithium is a preferred anode material because it is very electropositive and light in weight, However, other alkali metal materials, such as sodium, may be practiced within the scope of the present invention.
Electrolyte layer 16, which is ionically but not electrically conductive, takes the form of a solid material and is laminated to the alkali metal anode layer 18 and the cathode layer 14.
2016~17 The preferred electrolytes are solutions of an ionizable al~all metal salt or an alkaline earth salt,an aprotic solvent and a polymerl2able compound. Still more preferred are solutions of an alkali metal salt, a liquid, monomeric or prepolymeric radiatlon or thermally polymerizable compound and a radiation or thermally inert ionically conducting liquid.
Polymerizable compounds useful in the electrolyte composition may yield either a conductive or nonconductive polymer. Compounds which yield a conductive polymer contain a heteroatom capable of forming donor-acceptor bonds with the alkali metal cation. Useful polymerizable compounds are described next.
Polyethylenically unsaturated monomeric or prepolymonomeric materials useful in the present invention are preferably co~pounds having at least one, and more preferably a plurality, of heteroatoms (particularly oxygen and/or nitrogen atoms) capable of forming donor acceptor bonds with an al~ali metal cation and are terminated by polymerizable moieties. These compounds yield a conductive supportive matrix. More specifically they are preferably low molecular weight oligomers of the formulae (I)-(III) below A -(-CH2-~CH-O-)~n A (I) R
A -(-cH2-cH2-l-)-n A (II) R
A -t-CH2-~N-CH2-) n A (III) 40002-lO30 2 ~ 1 7 where n is about 3 to 50 and R is hydrogen or a C1-C3 alkyl group which is terminated by ethylenically unsaturated moieties or glycidyl moieties represented by A. A
particularly useful group of compounds is obtained by reacting a polyethylene glycol with acrylic or methacrylic acid. Polyethylene glycol diacrylate is a particularly preferred polymer. To provide additional structural integrity, triacrylate prepolymers may be added.
ereferably~ the radiation or thermally inert ionically conductive liquids have a boiling point greater than 80 C. Examples of these liquids include -butyrolactone, propylene carbonate, 1,3-dioxolane and 2-methyltetrahydrofuran. Less polar solvents having heteroatoms capable of bonding alkali metal cations are also useful. Polyethylene glycol dimethyl ether (PEGDME) is one such example. Glymes such as tetraglyme, hexaglyme, and heptaglyme are also desirable solvents. Propylene carbonate is a preferred solvent.
As to the ionizable salt, formula MX, this is not limiting at all, and is the type in which:
M+=Li+, Na+, K~, Ca2+, Mg2+, NH4+
X-=I-, C104-, BF4-, AsF~-, CF3SO3-, CF3CO3-, PF6-sl2Hl22-~ B1oClo2-, B~4-,~ designating C6Hs, or an alkyl or an aryl chain.
To produce a solid electrolyte material, the solution of the ionizable salt and inert ionically conductive liquid is mixed with the curable composition and the mixture is cured by exposure to actinic radiation, preferably electron beam or ultraviolet radiation or by heating if a thermally curable system is utilized. If ultraviolet radiation is used for curing, an ultraviolet photoinitiator may be added to the composition. Similarly if a thermally curable composition is selected, a thermal 20~17 lnitiator should be present in the composition. ~xamples of thermally curable compositions are disclosed in U.S. Patent No. 4,792,504, which is hereby incorporated by reference.
Alternatively, the electrolyte can ta~e the form of a solid solution of an alkali or al~aline earth salt in a curable polymerizable compound. In still another embodiment, the solid solution may include a plasticizer or liquid electrolyte in addition to the solid solution.
The cathode composition layer 14 includes a cathode material which is coated on the microroughened 13 surface of the current collector 12.
Cathode compositions are known in the art.
Typically they comprise an intercalation compound, an ionically conductive solid polymer electrolyte containing solution of an alkali metal salt or alkaline earth salt as defined above, and an electrically conductive filler. A
typical formulation may contain about 25 to about 70 parts by weight of intercalation compound, about 2 to about 15 parts of an electrically conductive filler, and about 15 to about 75 parts of the ionically conductive electrolyte.
The following compounds have been taught in the art for use as intercalation compounds: V6O13, MoO2, MnO2, V2O5~ TiS2~ MoS3~ Cr3~6~ LiXV3Og~ V3O8~ VS2, NbSe2, FeOCl, CrOBr, TiNCl, ZrNCl, HfNBr, FeS, NiS, Co0, Cu0 and WO2.
V6O13 is particularly preferred. For use as an electrically conductive filler, carbon may be used.
In addition to providing a matrix for containing the alkali metal salt, the ionically conductive polymer additionally functions as a binder material to enable the cathode composition to adhere to the collector substrate.
~ecause of its adhesive qualities, acrylated polyethylene oxide is the preferred ionically conductive polymer. For use as an additional adhesive, acrylated polyesters may be --selected.
The process for producing cell 10 is as follows.
Because the cell produced utilizes an alkali metal anode layer, usually a lithium anode layer, it is necessary to manufacture the cell in a water (humidity) free environment.
Lithium is extremely reactive with water and if reacted, a passivation layer can form on the surface of the anode layer, reducing the efficiency of the layer, and increasing cell impedance. Accordingly, it is particularly desirable to manufacture the cell in an environment having a relative humidity at room temperature of less than 2% (less than 300 ppm water). An environment containing between 1 ppm and 50 ppm water produces a particularly efficient cell.
Cathode composition 14 as defined above is coated onto the microroughened surface of current collector 12.
Cathode composition 14 is paste-like in consistency.
Coating may be accomplished using conventional coating techniques such as doctor blade or coating an extrusion method. In practice, the optimum thickness ranges between about 25 and about 250 microns. In order to obtain a one-hour discharge with 75-100% utilization of the cathode composition, the layer thickness ranges between 50 and 100 microns in thickness. Where a faster discharge rate is desired, a lower thickness may be selected. ~onversely, if a slower discharge rate is desired, a thic~er layer may be provided. In practice, the cathode composition layer has an impedance less than 50 ohms/cm2.
After cathode composition 14 has been coated onto current collector 12, the top surface of the cathode layer is optionally rolled by utilizinq a non-stic~ pressure roller such as a PTFE roller. Alternatively, if the cathode composition stic~s to the surface of the roller, a non-stic~
release liner, not pictured, may be placed onto the upper surface, the roller can traverse the length of the release liner, and the release liner can then be removed. Rolling 40002-1030 -14- 2016~17 the upper surface of the cathode layer benefits in that it improves adherence between cathode composition 14 and current collector 12 and produces a smoother surface which enables a very thin electrolyte layer to be coated thereon.
As a result of the surface rolling, the open circuit voltage discharge associated with cathode composition 14 is significantly reduced as compared to a cell whose cathode does not have a rolled surface. Accordingly, the overall cell efficiency is improved.
The utilization of microroughened surface 13 of the current coilector 12 along with the optional pressure rolling step following the coating of cathode composition 14 onto current collector 12 enables a tightly adherent contact to occur between the respective materials. This, in turn, reduces imre~nce at the collector/cathode composition interface. The impedance at the interface is typically less than 10 ohms/cm2 and, in the preferred embodiment, less than 5 ohms/cm2.
Electrolyte layer 16 is coated as a thin film onto the cathode composition layer 14. The electrolyte can be extruded and coated in a very thin layer, typically ranging from about 5 microns to about 25 microns. The ability to coat in a thin layer is in large part due to the continuous surface of cathode composition. When electrolyte 16 is coated onto cathode 14, it is coated in an uncured liquid state. As is readily understood, electrolyte layer 16 must completely coat cat~ode composition layer 14 to prevent the intercalation compound and electrically conductive filler from protruding through electrolyte layer 16. The thickness of electrolyte layer 16 need only be thic~ enough to completely coat the upper surface of the cathode composition.
Once electrolyte layer 16 has been coated onto cathode composition 14, the asse0bly is partially or totally 40002-1030 -15- 2 0 1 6 ~ 1 7 cured by radiation or thermal means. In practice, exposure of the assembly to an electron beam operating at a power of 3 to 9 Mrad is particularly preferred. Alternatively an ultraviolet or thermal source may be selected. If an ultraviolet source is selected, the monomer preferabLy includes an ultraviolet initiator of the type commonly known in the art such as thioxanthone initiators. If a thermal source is selected, the monomer preferably includes a thermal initiator of the type commonly known in the art such as those disclosed in U.S. Patent No. 4,792,504 to Scbwab et al. Curing the cathode composition and the electrolyte polymerizes and crosslinks and thereby solidifies the monomeric material by conversion ~o a polymeric form.
A partial curinq step (as opposed to ~ull curing) may be particularly desirable as this enables the electrolyte layer 16 to remain somewhat tac~y. This enables better adherence between the electrolyte and the anode layer, when coated.
After partial or total curing of cathode composition 14 and electrolyte 16, alkali metal anode layer 18 is applied to electrolyte layer 16. Although not pictured, a thin polymeric material such as a porous polypropylene sheet may be interposed between the anode and the electrolyte to ensure that the anode does not contact the cathode layer, particularly at the outer edges of the respective layers. Use of the polymeric sheet is optional.
After anode layer 18 is coated onto electrolyte 16, the entire assembly is optionally passed through pressure rollers. The pressure rolling step aids in the adhesion of the layers to each other, thereby reducing interfacial il o~ance between component layers.
If the cathode composition 16 and electrolyte 14 have not been completely cured, the entire assembly is again cured by exposure to actinic radiation, preferably electron 40002-1030 -16- 2 0 1 ~ .~ 1 7 beam radiation or by thermally curing. This step functions to solidify the cathode composition and electrolyte layers, thereby producing a solid state cell.
Once the current collector, cathode composition, electrolyte composition and anode composition have been assembled, electrodes are attached to the anode and current collector layers by means known in the art. The assembly is then inserted into an air and water impermeable protective material 20 and the edges of the protective material are sealed, preferably by heat sealing around edges of the cell components. Sealing preferably occurs under vacuum conditions to enable the protective material to form a tightly adherent seal around the component layers and electrodes such that the only external access to the component layers is via the electrodes.
Examples of the heat sealable gas and water impermeable protective materials include a multi-layered material having an interior heat sealable layer comprising ethylene acrylic acid, an intermediate barrier layer comprising aluminum foil, and an exterior layer of polyethylene terephthalate. Other heat sealable protective materials known in the art can be used in accordance with the present invention. The protective materials should be as thin as possible to minimize the overall thickness of the cell. Commercially available heat sealable materials of ~he types described above can have an overall thickness of less than 200 microns.
Once the components have been inserted and sealed in the protective ~aterial, the cell is available for use by simply connecting the electrodes to the device to be powered. When utilizing a single lithium anode cell, the cell generates a voltage of approxim~tely 2.7 volts and a current flow exceeding 50 milliamps/cm2.
Referring now to Fig. 5 an alternative current collector is shown and designated as l00. Collector 100 includes polymeric substrate 102 having coated thereon a layer of an electrically conductive material 104.
Optionally overcoated on material 104 is another layer of an electrically conductive material 106. Substrate 102 may be selected from polymeric film materials including polyethylene, polyethylene terephthalate and polyvinyl chloride. The thickness of film 102 is extremely thin, with 10' thickness of less than 5 microns and even about 1 micron possible. This enables the manufacture of very thin current collectors, and hence, very thin l~ in~r cells.
Electrically conductive materials 104 or 106 may be any of the materials as discussed with respect to Fig. 2.
Examples of such materials may include copper, carbon, aluminum, nickel, steel, lead and iron and combinations thereof.
Alternatively, examples of other electrically conductive materials may include electrically conductive inks. Such inks are known in the art and are typically used for screen printing, manufacture of membrane switches, EL
lamps and displays, and flexible circuits. Examples of silver filled and indium oxide-filled electrically conductive inks are manufactured by Zymet Inc. of East Hanover, New Jersey. The inks are applied onto the polymeric film in a patterned form such as a grid, mesh, spiral, and the like. Depending on the thickness of the ink layer, an extremely thin current collector can be produced.
Referring to Fig. 6, an electron microscope side view photograph of a current collector manufactured in accordance with the present invention is shown. Collector 100A includes polyethylene terephthalate film 102A
overcoated with a vapor deposited first layer of copper 104A
which is overcoated with an electrodeposited layer of nickel particles 106A. The overall thickness of this collector is about 1 to 5 microns.
The invention is further explained in the following non limiting examples.
40002-1030 -18- 2016~7 Comparative ExamPle 1 A cell was produced by first forming a cathode mixture including 45% by weight V6O13, 4% carbon and 51% of an electrolyte including 70% propylene carbonate, 3%
polyethylene oxide, 6% LiCF3S03 and 21% of a radiation curable acrylate. This mixture was coated onto a 15 micron thick solid nickel foil current collector to a thickness of about 75 microns having a surface area of about 32cm2. The above defined electrolyte was then coated onto the cathode to a thickness of about 50 microns. A 100 micron thick lithium foil was then laminated onto the electrolyte and the entire structure was subjected to electron beam radiation to cure the cathode and electrolyte. The initial cell impedance at 1 Hz was measured to be about 110 ohms.
Example 2 A cell having the identical cathode, electrolyte and anode of Comparative Example 1 was produced by using a 35 micron thick nickel foil current collector having a surface area of about 32cm2 which was etched to provide a roughened surface. The measured impedance at 1 Hz was 12 ohms.
ComParative Example 3 A cell was prepared identical to the cell of Cs ~rative Example 1 with the exception that the cathode contained 53% V6O13, 8~ carbon and 39% electrolyte. The measured cell impedance at 1 Hz was 150 ohms.
Example 4 A cell having the identical cathode, electrolyte and anode of Comparative Example 3 was produced using the current collector of Example 2. The measured impedance at 1 Hz was 5 ohms.
2016~17 Example 5 The cell of Comparative Example 3 was discharged at 200 microamperes/cm2 at room temperature to lower the voltage from 3 V to l.S V. The discharge time was 15 hours.
Example 6 The experiment of Example 5 was repeated using the cell of Example 4. The discharge time was 17.5 hours.
Example 7 In an inert, nitrogen environment, a cathode composition is prepared by grinding 300 parts of V6O13 for 24 to ~8 hours in the presence of an equal amount of tetrahydrofuran in a one liter ball mill using 1.25 cm diameter ceramic balls. After grinding, the average particle size of V6O13 is about 1.5 microns. The slurry is transferred to an airtight mixer and 46.2 parts of predried carbon are added to the mixer to produce a slurry having a weight ratio of V6O13 to C of about 6.5 to 1. The mixture is stirred at low speed (20 rpm) under vacuum and heat, until the tetrahydrofuran is evaporated. The overall water content of the mixture is less than 100 ppm. 3 parts of polyethylene oxide ~PEO) having a molecular weight greater than 100,000 is added to the V6O13/C powder mixture. The mixture is stirred for about 10 to 20 minutes to adequately disperse the polyethylen~e oxide. ~ ~ , Propylene carbonate (PC), polyethylene glycol ~ - ~yl ~t~r ~ ~C/~
(PEG ~ ), and trimethylolpropane ethoxylated triacrylate (TMPEOTA) are added to the mixture to produce a mixture having the following components:
component Percent (weiqht) V6~13 45 PEO
PEGDA 8.5 TMPEOTA 1.5 2016~ 17 The mixture temperature is increased to 65 C and the mixture is stirred at low speed for 20 minutes. The speed of the mixer is increased to 75 rpm and the mixture is stirred for 2 to 3 additional hours.
The mixture is then coated onto a 5cm x 20cm x 25 micron high surface treated nickel foil available from Eukuda Metal Foil & Powder Co. Ltd. of Kyoto, Japan by utilizing a doctor blade technique at 50-60'C in a completely inert (nitrogen) environment containing less than 25 ppm water. The thickness of the cathode --layer is 75 microns and the cathode layer is then covered with a stainless steel foil. A 2 inch diameter, 10 inch long stainless steel roller is placed on top of the foil and the roller is rolled along the length of the foil at a pressure of 5-10 kg/cm2 to improve adherence of the cathode layer to the current collector. The assembly is then irradiated with a 3 Mrad dose of radiation by utilizing an electron beam source to cure the cathode layer. The foil is then peeled off of the cathode layer.
The impedance of the cathode is less than 50 ohm/cm2.
An electrolyte is prepared by mixing together the following components in the following weight fractions:
component ~ercent (weight) LiAsF6 18 PEO 2.5 25 eEGDA 9.2 TMPEOTA 2.3 The overall water concentration of the electrolyte is less than 50 ppm. The electrolyte is coated onto the cathode layer by using a doctor blade at room temperature to a thic~ness of about 25 microns. The electrolyte is then irradiated with a 3 Mrad dose of radiation from an electron beam source. The impedance of the electrolyte layer is about 0.8 ohm/cm2.
2~1fi-)17 A 4cm x 12.5cm x 125 micron thick lithium s~rip (lithium metal/battery grade) available from Lithco of ~essemer City, NC
is applied tO one end of the electrolyte layer and the lithium strip is adhered to the layer by applying pressure from a 2 inch diameter, 10 inch long roller at 5-10 kg/cm2 across the entire lithium surface. The opposite end of the electrolyte/cathode/current collector assembly is folded over the anode layer to form a bifaced cell. Copper tabs were spot welded to the current collector and pressure rolled onto the lithium foil to form electrodes for connection to a device.
The physical and mechanical properties of the produced battery were as follows:
property value surface area 100 cm2 volume 2 cm3 capacity 250 mAh average voltage 2.4 V
discharge time (50 mA drain) S hours - discharge time (250 mA drain) 0.5 hours discharge time (10 A pulses) 1.5 minutes energy density 300 wh/l overall impedance 150 ohm/cm2 Having described the invention in detail and by reference to preferred embodiments thereof, it will be apparent that modifications and variations are possible without departing from the scope of the invention defined in the appended claims.
What is claimed is:
Claims (25)
1. A solid state laminar electrochemical cell comprising:
an alkali metal anode layer;
a solid ionically conductive electrolyte layer;
a cathode composition layer; and a current collector;
wherein said electrolyte layer is interposed between said alkali metal anode layer and said cathode layer and said cathode layer is interposed between said electrolyte layer and said current collector, characterized in that the surface of said current collector which contacts said cathode layer is microroughened and the cathode composition is at least partially cured in contact with said microroughened surface to enable the cathode layer to tightly adhere to said current collector.
an alkali metal anode layer;
a solid ionically conductive electrolyte layer;
a cathode composition layer; and a current collector;
wherein said electrolyte layer is interposed between said alkali metal anode layer and said cathode layer and said cathode layer is interposed between said electrolyte layer and said current collector, characterized in that the surface of said current collector which contacts said cathode layer is microroughened and the cathode composition is at least partially cured in contact with said microroughened surface to enable the cathode layer to tightly adhere to said current collector.
2. The cell according to claim 1 wherein said anode layer comprises lithium foil, a metal foil coated with a layer of lithium or a lithium alloy.
3. The cell according to claim 2 wherein said current collector comprises a metal foil substrate and wherein said microroughened surface is produced by electrodepositing a metal particles on said foil.
4. The cell according to claim 3 wherein said metal foil substrate and said electrodeposited metal are the same metal.
5. The cell according to claim 4 wherein said metal is selected from the group consisting of carbon, copper, aluminum, nickel, steel, lead and iron and combinations thereof.
6. The cell according to claim 5 wherein said metal comprises nickel.
7. The cell according to claim 2 wherein said current collector comprises a polymeric substrate and wherein said microroughened surface is produced by depositing an electrically conductive material on said substrate.
8. The cell according to claim 7 wherein said polymeric substrate is selected from the group consisting of polyethylene, polyethylene terephthalate and polyvinyl chloride.
9. The cell according to claim 8 wherein said electrically conductive material is a metal selected from the group consisting of carbon, copper, aluminum, nickel, steel, lead and iron and combinations thereof.
10. The cell according to claim 9 wherein said substrate comprises polyethylene terephthalate and said deposited metal comprises a first layer of copper and a second layer of nickel coated onto said first layer.
11. The cell according to claim 8 wherein said electrically conductive material comprises an electroconductive ink.
12. The cell according to claim 2 wherein said electrolyte layer comprises a layer of an ionizable alkali metal salt or an alkaline earth salt, an inert liquid solvent for said salt and a polymerizable material.
13. The cell according to claim 12 wherein said salt is a salt of a metal cation selected from the group consisting of Li+, Na+, K+, Mg2+, Ca2+ and NH4+, and an anion selected from the group consisting of I-, C10 4-, BF4-, AsF6-, PF6-CF3SO3-, CF3CO3-, B12H12 2-, B10Cl10 2-, and B~4-, where ~ is C6H5, an alkyl chain or an aryl chain, and wherein said salt cation and said salt anion are maintained in stoichiometric amounts.
14. The cell according to claim 2 wherein said cathode composition comprises an intercalation compound, an electrically conductive filler and an ionically conductive electrolyte.
15. The cell according to claim 14 wherein said intercalation compound comprises V6O13, said electrically conductive filler comprises carbon particles and said ionically conductive electrolyte of said cathode composition comprises a solution of an ionizable alkali metal salt or alkaline earth salt and an inert liquid solvent for said salt, and a polymerizable material.
16. A current collector for contacting the cathode layer of a solid state alkali metal anode electrochemical laminar cell comprising a metal foil, the surface of said metal foil which is to contact the cathode layer being microroughened.
17. The current collector according to claim 16 wherein said metal is selected from the group consisting of carbon, copper, aluminum, nickel, steel, lead and iron and combinations thereof.
18. The current collector according to claim 17 wherein said microroughened surface is produced by electrodepositing metal particles on said foil.
19. The current collector according to claim 18 wherein said metal foil substrate and said electrodeposited metal are the same metal.
20. The current collector according to claim 19 wherein said metal comprises nickel.
21. A current collector for contacting the cathode layer of a solid state electrochemical laminar cell comprising a polymeric substrate having an electrically conductive material deposited on said substrate which is to contact the cathode layer.
22. The current collector according to claim 21 wherein said polymeric substrate is selected from the group consisting of polyethylene, polyethylene terephthalate and polyvinyl chloride.
23. The current collector according to claim 22 wherein said electrically conductive material is a metal selected from the group consisting of carbon, copper, aluminum, nickel, steel, lead and iron and combinations thereof.
24. The current collector according to claim 23 wherein said substrate comprises polyethylene terephthalate and said deposited metal comprises a first layer of copper and a second layer of nickel coated onto said first layer.
25. The current collector according to claim 22 wherein said electrically conductive material comprises an electroconductive ink.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US35087489A | 1989-05-11 | 1989-05-11 | |
| US350,874 | 1989-05-11 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2016517A1 CA2016517A1 (en) | 1990-11-11 |
| CA2016517C true CA2016517C (en) | 1999-01-12 |
Family
ID=23378567
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002016517A Expired - Fee Related CA2016517C (en) | 1989-05-11 | 1990-05-10 | Solid state electrochemical cell having microroughened current collector |
Country Status (6)
| Country | Link |
|---|---|
| US (1) | US5436091A (en) |
| EP (1) | EP0397523B1 (en) |
| JP (1) | JP3046323B2 (en) |
| CA (1) | CA2016517C (en) |
| DE (1) | DE69028240T2 (en) |
| ES (1) | ES2092490T3 (en) |
Families Citing this family (106)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0592684A4 (en) * | 1992-04-06 | 1995-12-13 | Yuasa Battery Co Ltd | Cell |
| US5360684A (en) * | 1993-10-25 | 1994-11-01 | Hydro-Quebec | Electrochemical cell for polymer electrolyte-lithium batteries (ACEP) |
| JP3387724B2 (en) * | 1995-03-17 | 2003-03-17 | キヤノン株式会社 | Electrode for secondary battery, method of manufacturing the same, and secondary battery having the electrode |
| US5656081A (en) * | 1995-06-07 | 1997-08-12 | Img Group Limited | Press for printing an electrical circuit component directly onto a substrate using an electrically-conductive liquid |
| US5758575A (en) * | 1995-06-07 | 1998-06-02 | Bemis Company Inc. | Apparatus for printing an electrical circuit component with print cells in liquid communication |
| IT1277374B1 (en) * | 1995-07-28 | 1997-11-10 | Eniricerche Spa | PROCEDURE FOR THE PREPARATION OF A CURRENT COLLECTOR IN CONTACT WITH THE CATHODIC MATERIAL |
| IT1277375B1 (en) * | 1995-07-28 | 1997-11-10 | Eniricerche Spa | COMPOSITE CATHOD PROCEDURE FOR ITS PREPARATION AND ITS USE IN SOLID ELECTROCHEMICAL CELLS |
| US5582935A (en) * | 1995-09-28 | 1996-12-10 | Dasgupta; Sankar | Composite electrode for a lithium battery |
| CA2224236A1 (en) * | 1995-10-07 | 1997-04-17 | Img Group Limited | An electrical circuit component formed of a conductive liquid printed directly onto a substrate |
| US5580686A (en) * | 1995-10-13 | 1996-12-03 | Arthur D. Little, Inc. | Electrolytic cell and electrolytic process |
| IT1276151B1 (en) * | 1995-11-17 | 1997-10-27 | Eniricerche Spa | ELECTROLYTIC MEMBRANE AND PROCEDURE FOR ITS PHOTO-CROSS LINKAGE ON CATHODE MEMBRANE |
| AU2591397A (en) * | 1996-07-02 | 1998-01-21 | Wilson Greatbatch Ltd. | Preparation and use of thin flexible cathodes in alkali metal electrochemical cells |
| AU3110197A (en) | 1996-11-11 | 1998-06-03 | Gorina, Liliya Fedorovna | Method for manufacturing a single unit high temperature fuel cell and its components: a cathode, an electrolyte, an anode, a current conductor, and interface and insulating layers |
| JPH10334948A (en) * | 1997-05-30 | 1998-12-18 | Tdk Corp | Electrode, lithium secondary battery, and electric double layer capacitor using the electrode |
| US6217623B1 (en) * | 1997-11-03 | 2001-04-17 | Motorola, Inc. | Method of fabricating an electrochemical device |
| US6117593A (en) * | 1998-06-15 | 2000-09-12 | Johnson Manufacturing, Llc | Current collector manufacture by arc spray deposition |
| US6048646A (en) * | 1998-07-21 | 2000-04-11 | Ga-Tek Inc. | Method for treating copper current collectors for Li-ion and/or Li-ion polymer batteries |
| US6110622A (en) * | 1998-07-22 | 2000-08-29 | Wilson Greatbatch Ltd. | Chemically machined current collector design |
| US6046268A (en) * | 1998-08-02 | 2000-04-04 | Motorola, Inc. | Electrode with enhanced adhesion to substrates |
| US6521381B1 (en) * | 1999-03-16 | 2003-02-18 | General Motors Corporation | Electrode and membrane-electrode assemblies for electrochemical cells |
| JP2002541634A (en) * | 1999-03-31 | 2002-12-03 | コーニンクレッカ フィリップス エレクトロニクス エヌ ヴィ | Method of applying a conductive current collector on a self-supporting electrode, and assembly of electrode and current collector |
| US6228536B1 (en) * | 1999-07-13 | 2001-05-08 | Hughes Electronics Corporation | Lithium-ion battery cell having an oxidized/reduced negative current collector |
| US6223449B1 (en) | 1999-11-18 | 2001-05-01 | Johnson Research & Development Company, Inc. | Apparatus for extracting plasticizer |
| US6733924B1 (en) * | 1999-11-23 | 2004-05-11 | Moltech Corporation | Lithium anodes for electrochemical cells |
| US6737180B2 (en) | 2000-04-10 | 2004-05-18 | Johnson Electro Mechanical Systems, Llc | Electrochemical conversion system |
| US6686076B2 (en) | 2000-04-10 | 2004-02-03 | Excellatron Solid State, Llc | Electrochemical conversion system |
| US6709778B2 (en) | 2000-04-10 | 2004-03-23 | Johnson Electro Mechanical Systems, Llc | Electrochemical conversion system |
| US6899967B2 (en) | 2000-04-10 | 2005-05-31 | Excellatron Solid State, Llc | Electrochemical conversion system |
| US6344293B1 (en) * | 2000-04-18 | 2002-02-05 | Moltech Corporation | Lithium electrochemical cells with enhanced cycle life |
| US7943250B1 (en) | 2000-07-28 | 2011-05-17 | Johnson Research & Development Co., Inc. | Electrochemical conversion system for energy management |
| US6815121B2 (en) * | 2000-07-31 | 2004-11-09 | Electrovaya Inc. | Particulate electrode including electrolyte for a rechargeable lithium battery |
| US20030064269A1 (en) * | 2001-10-02 | 2003-04-03 | Kelly Sean M. | Fuel cell stack having a featured interconnect element |
| US20070094865A1 (en) * | 2002-01-10 | 2007-05-03 | Ji-Guang Zhang | Packaged thin film batteries and methods of packaging thin film batteries |
| US7960054B2 (en) * | 2002-01-10 | 2011-06-14 | Excellatron Solid State Llc | Packaged thin film batteries |
| CA2380900A1 (en) * | 2002-04-08 | 2003-10-08 | Jeffrey Phillips | High rate, thin film, bipolar nickel zinc battery |
| EP1502502A1 (en) * | 2002-04-18 | 2005-02-02 | Eamex Corporation | Display device for appreciation |
| JP4224995B2 (en) * | 2002-07-18 | 2009-02-18 | 日本電気株式会社 | Secondary battery and current collector for secondary battery |
| JP3935067B2 (en) * | 2002-12-26 | 2007-06-20 | ソニー株式会社 | Secondary battery negative electrode and secondary battery using the same |
| KR100611940B1 (en) * | 2003-11-21 | 2006-08-11 | 주식회사 엘지화학 | Electrochemical cell having an improved safety |
| US8828610B2 (en) * | 2004-01-06 | 2014-09-09 | Sion Power Corporation | Electrolytes for lithium sulfur cells |
| US7358012B2 (en) | 2004-01-06 | 2008-04-15 | Sion Power Corporation | Electrolytes for lithium sulfur cells |
| US10297827B2 (en) | 2004-01-06 | 2019-05-21 | Sion Power Corporation | Electrochemical cell, components thereof, and methods of making and using same |
| US20080070087A1 (en) * | 2004-02-20 | 2008-03-20 | Excellatron Solid State, Llc | Non-volatile cathodes for lithium oxygen batteries and method of producing same |
| US10566669B2 (en) | 2004-02-20 | 2020-02-18 | Johnson Ip Holding, Llc | Lithium oxygen batteries having a carbon cloth current collector and method of producing same |
| US7901730B2 (en) * | 2004-04-26 | 2011-03-08 | Johnson Research & Development Co., Inc. | Thin film ceramic proton conducting electrolyte |
| US8568921B1 (en) | 2004-08-18 | 2013-10-29 | Excellatron Solid State Llc | Regenerative ion exchange fuel cell |
| US8730031B2 (en) | 2005-04-28 | 2014-05-20 | Proteus Digital Health, Inc. | Communication system using an implantable device |
| US9198608B2 (en) | 2005-04-28 | 2015-12-01 | Proteus Digital Health, Inc. | Communication system incorporated in a container |
| US8912908B2 (en) | 2005-04-28 | 2014-12-16 | Proteus Digital Health, Inc. | Communication system with remote activation |
| EP3827747A1 (en) | 2005-04-28 | 2021-06-02 | Otsuka Pharmaceutical Co., Ltd. | Pharma-informatics system |
| US8836513B2 (en) | 2006-04-28 | 2014-09-16 | Proteus Digital Health, Inc. | Communication system incorporated in an ingestible product |
| US8802183B2 (en) | 2005-04-28 | 2014-08-12 | Proteus Digital Health, Inc. | Communication system with enhanced partial power source and method of manufacturing same |
| US8547248B2 (en) | 2005-09-01 | 2013-10-01 | Proteus Digital Health, Inc. | Implantable zero-wire communications system |
| JP2009524900A (en) * | 2005-10-11 | 2009-07-02 | エクセラトロン ソリッド ステート，エルエルシー | Lithium battery manufacturing method |
| WO2007106742A2 (en) | 2006-03-10 | 2007-09-20 | Excellatron Solid State Llc | Air battery and manufacturing method |
| JP2009544338A (en) | 2006-05-02 | 2009-12-17 | プロテウス バイオメディカル インコーポレイテッド | Treatment regimen customized to the patient |
| US20080020037A1 (en) * | 2006-07-11 | 2008-01-24 | Robertson Timothy L | Acoustic Pharma-Informatics System |
| US7718319B2 (en) | 2006-09-25 | 2010-05-18 | Board Of Regents, The University Of Texas System | Cation-substituted spinel oxide and oxyfluoride cathodes for lithium ion batteries |
| KR101611240B1 (en) | 2006-10-25 | 2016-04-11 | 프로테우스 디지털 헬스, 인코포레이티드 | Controlled activation ingestible identifier |
| US7851089B2 (en) * | 2006-10-26 | 2010-12-14 | Panasonic Corporation | Electrode plate for battery and lithium secondary battery including the same |
| WO2008063626A2 (en) | 2006-11-20 | 2008-05-29 | Proteus Biomedical, Inc. | Active signal processing personal health signal receivers |
| MY165532A (en) | 2007-02-01 | 2018-04-02 | Proteus Digital Health Inc | Ingestible event marker systems |
| EP2111661B1 (en) | 2007-02-14 | 2017-04-12 | Proteus Digital Health, Inc. | In-body power source having high surface area electrode |
| EP2063771A1 (en) | 2007-03-09 | 2009-06-03 | Proteus Biomedical, Inc. | In-body device having a deployable antenna |
| US8540632B2 (en) | 2007-05-24 | 2013-09-24 | Proteus Digital Health, Inc. | Low profile antenna for in body device |
| EP4011289A1 (en) | 2007-09-25 | 2022-06-15 | Otsuka Pharmaceutical Co., Ltd. | In-body device with virtual dipole signal amplification |
| JP2011513865A (en) | 2008-03-05 | 2011-04-28 | プロテウス バイオメディカル インコーポレイテッド | Multi-mode communication ingestible event marker and system and method of using the same |
| WO2009117496A2 (en) * | 2008-03-20 | 2009-09-24 | Excellatron Solid State, Llc | Oxygen battery system |
| JP2009295331A (en) * | 2008-06-03 | 2009-12-17 | Sony Corp | Anode collector, its forming method, anode, and secondary battery |
| WO2010005877A2 (en) | 2008-07-08 | 2010-01-14 | Proteus Biomedical, Inc. | Ingestible event marker data framework |
| KR101214453B1 (en) | 2008-08-13 | 2012-12-24 | 프로테우스 디지털 헬스, 인코포레이티드 | Ingestible circuitry |
| SG172077A1 (en) | 2008-12-11 | 2011-07-28 | Proteus Biomedical Inc | Evaluation of gastrointestinal function using portable electroviscerography systems and methods of using the same |
| WO2013012869A1 (en) | 2011-07-21 | 2013-01-24 | Proteus Digital Health, Inc. | Mobile communication device, system, and method |
| CN102341031A (en) | 2009-01-06 | 2012-02-01 | 普罗秋斯生物医学公司 | Ingestion-related biofeedback and personalized medical therapy method and system |
| EP3395333A1 (en) | 2009-01-06 | 2018-10-31 | Proteus Digital Health, Inc. | Pharmaceutical dosages delivery system |
| GB2480965B (en) | 2009-03-25 | 2014-10-08 | Proteus Digital Health Inc | Probablistic pharmacokinetic and pharmacodynamic modeling |
| MX2011011506A (en) | 2009-04-28 | 2012-05-08 | Proteus Biomedical Inc | Highly reliable ingestible event markers and methods for using the same. |
| US9149423B2 (en) | 2009-05-12 | 2015-10-06 | Proteus Digital Health, Inc. | Ingestible event markers comprising an ingestible component |
| US8558563B2 (en) | 2009-08-21 | 2013-10-15 | Proteus Digital Health, Inc. | Apparatus and method for measuring biochemical parameters |
| TWI517050B (en) | 2009-11-04 | 2016-01-11 | 普羅托斯數位健康公司 | System for supply chain management |
| UA109424C2 (en) | 2009-12-02 | 2015-08-25 | PHARMACEUTICAL PRODUCT, PHARMACEUTICAL TABLE WITH ELECTRONIC MARKER AND METHOD OF MANUFACTURING PHARMACEUTICAL TABLETS | |
| WO2011127252A2 (en) | 2010-04-07 | 2011-10-13 | Proteus Biomedical, Inc. | Miniature ingestible device |
| TWI557672B (en) | 2010-05-19 | 2016-11-11 | 波提亞斯數位康健公司 | Computer system and computer-implemented method to track medication from manufacturer to a patient, apparatus and method for confirming delivery of medication to a patient, patient interface device |
| WO2012025543A1 (en) | 2010-08-24 | 2012-03-01 | Basf Se | Electrolyte materials for use in electrochemical cells |
| EP2642983A4 (en) | 2010-11-22 | 2014-03-12 | Proteus Digital Health Inc | Ingestible device with pharmaceutical product |
| US8735002B2 (en) | 2011-09-07 | 2014-05-27 | Sion Power Corporation | Lithium sulfur electrochemical cell including insoluble nitrogen-containing compound |
| WO2015112603A1 (en) | 2014-01-21 | 2015-07-30 | Proteus Digital Health, Inc. | Masticable ingestible product and communication system therefor |
| US9756874B2 (en) | 2011-07-11 | 2017-09-12 | Proteus Digital Health, Inc. | Masticable ingestible product and communication system therefor |
| US9235683B2 (en) | 2011-11-09 | 2016-01-12 | Proteus Digital Health, Inc. | Apparatus, system, and method for managing adherence to a regimen |
| DE102012103834A1 (en) * | 2012-05-02 | 2013-11-07 | Hydro Aluminium Rolled Products Gmbh | Textured current collector foil |
| KR101987008B1 (en) * | 2012-06-15 | 2019-06-12 | 한국전자통신연구원 | Solid polymer electrolytes, methods for manufacturing the same, and lithum cell including thereof |
| TW201424689A (en) | 2012-07-23 | 2014-07-01 | Proteus Digital Health Inc | Techniques for manufacturing ingestible event markers comprising an ingestible component |
| US9268909B2 (en) | 2012-10-18 | 2016-02-23 | Proteus Digital Health, Inc. | Apparatus, system, and method to adaptively optimize power dissipation and broadcast power in a power source for a communication device |
| US9577289B2 (en) | 2012-12-17 | 2017-02-21 | Sion Power Corporation | Lithium-ion electrochemical cell, components thereof, and methods of making and using same |
| US11149123B2 (en) | 2013-01-29 | 2021-10-19 | Otsuka Pharmaceutical Co., Ltd. | Highly-swellable polymeric films and compositions comprising the same |
| US10175376B2 (en) | 2013-03-15 | 2019-01-08 | Proteus Digital Health, Inc. | Metal detector apparatus, system, and method |
| JP6511439B2 (en) | 2013-06-04 | 2019-05-15 | プロテウス デジタル ヘルス， インコーポレイテッド | Systems, devices, and methods for data collection and outcome assessment |
| US9796576B2 (en) | 2013-08-30 | 2017-10-24 | Proteus Digital Health, Inc. | Container with electronically controlled interlock |
| US10084880B2 (en) | 2013-11-04 | 2018-09-25 | Proteus Digital Health, Inc. | Social media networking based on physiologic information |
| JP6576072B2 (en) * | 2015-03-31 | 2019-09-18 | 日立造船株式会社 | Manufacturing method of all-solid-state secondary battery |
| US11051543B2 (en) | 2015-07-21 | 2021-07-06 | Otsuka Pharmaceutical Co. Ltd. | Alginate on adhesive bilayer laminate film |
| CN109843149B (en) | 2016-07-22 | 2020-07-07 | 普罗秋斯数字健康公司 | Electromagnetic sensing and detection of ingestible event markers |
| JP2019535377A (en) | 2016-10-26 | 2019-12-12 | プロテウス デジタル ヘルス， インコーポレイテッド | Method for producing capsules with ingestible event markers |
| KR102204304B1 (en) * | 2017-12-27 | 2021-01-18 | 주식회사 엘지화학 | Li metal secondary battery and method for fabricating the same |
| WO2022198470A1 (en) * | 2021-03-24 | 2022-09-29 | 宁德新能源科技有限公司 | Current collector, electrochemical apparatus using current collector, and electronic device |
| DE102021212552A1 (en) | 2021-11-08 | 2023-05-11 | Volkswagen Aktiengesellschaft | Battery cell and method for producing such a battery cell |
Family Cites Families (43)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA894407A (en) * | 1972-02-29 | Siemens Aktiengesellschaft | Method and device for electrochemical energy conversion of hydrogen compounds | |
| FR1324107A (en) * | 1962-06-01 | 1963-04-12 | Accumulatoren Fabrik Ag | Accumulator comprising an intermediate layer containing synthetic material |
| FR1417112A (en) * | 1962-08-04 | 1965-11-12 | Siemens Ag | Process for the electrochemical transformation of dissolved, liquid or gaseous compounds containing hydrogen |
| CH442313A (en) * | 1963-03-18 | 1967-08-31 | Hoffmann La Roche | Process for the preparation of heterocyclic compounds |
| US3393098A (en) * | 1963-04-30 | 1968-07-16 | Leesona Corp | Fuel cell comprising a hydrogen diffusion anode having two layers of dissimilar metals and method of operating same |
| FR1408215A (en) * | 1964-04-30 | 1965-08-13 | Leesona Corp | Advanced fuel cell |
| US3449168A (en) * | 1965-08-03 | 1969-06-10 | United Aircraft Corp | Method for catalytically reforming carbonaceous feedstock to produce hydrogen for use in fuel cells |
| US3450567A (en) * | 1965-08-03 | 1969-06-17 | United Aircraft Corp | Method for producing hydrogen from hydrogen-containing feedstocks for use in fuel cell |
| NL6613162A (en) * | 1965-09-30 | 1967-03-31 | ||
| FR96366E (en) * | 1967-12-26 | 1972-06-16 | Gen Electric | Improvements in electrodes for fuel cells, and fuel cells. |
| US3956191A (en) * | 1974-05-02 | 1976-05-11 | Exxon Research And Engineering Company | Method for making bimetallic catalysts |
| US4036743A (en) * | 1976-09-20 | 1977-07-19 | Uop Inc. | Hydrocarbon conversion with an acidic multimetallic catalytic composite |
| US4202934A (en) * | 1978-07-03 | 1980-05-13 | United Technologies Corporation | Noble metal/vanadium alloy catalyst and method for making |
| US4186110A (en) * | 1978-07-03 | 1980-01-29 | United Technologies Corporation | Noble metal-refractory metal alloys as catalysts and method for making |
| FR2442512A1 (en) * | 1978-11-22 | 1980-06-20 | Anvar | NEW ELASTOMERIC MATERIALS WITH ION CONDUCTION |
| US4214970A (en) * | 1979-01-15 | 1980-07-29 | Diamond Shamrock Technologies, S.A. | Novel electrocatalytic electrodes |
| HU179808B (en) * | 1979-05-25 | 1982-12-28 | Villamos Ipari Kutato Intezet | Method for making electrodes consisting of current collector and active material |
| IN155181B (en) * | 1979-12-24 | 1985-01-12 | Chloride Silent Power Ltd | |
| DD156501A3 (en) * | 1980-11-03 | 1982-09-01 | Prazska Akumulatorka Np | ELECTRODES FOR ELECTROCHEMICAL ELECTRICITY SOURCES |
| US4416915A (en) * | 1982-02-04 | 1983-11-22 | Combustion Engineering, Inc. | Method of making chalcogenide cathodes |
| US4560632A (en) * | 1982-09-29 | 1985-12-24 | Union Carbide Corporation | Polyvinyl-coated cathode collector for cells employing liquid cathodes |
| US4522894A (en) * | 1982-09-30 | 1985-06-11 | Engelhard Corporation | Fuel cell electric power production |
| DE3472335D1 (en) * | 1983-04-22 | 1988-07-28 | Atomic Energy Authority Uk | Electrochemical cell |
| SE461095B (en) * | 1983-09-09 | 1990-01-08 | Berol Kemi Ab | AMINING PROCEDURE USING A RUTENIUM DOPPED NICKEL AND / OR COVOLT CATALYST |
| GB8412304D0 (en) * | 1984-05-14 | 1984-06-20 | Atomic Energy Authority Uk | Composite cathode |
| JPS6134865A (en) * | 1984-07-27 | 1986-02-19 | Hitachi Ltd | Fuel cell power generating system |
| JPS61260554A (en) * | 1985-05-15 | 1986-11-18 | Hitachi Ltd | Inside reforming type fuel cell |
| US4689475A (en) * | 1985-10-15 | 1987-08-25 | Raychem Corporation | Electrical devices containing conductive polymers |
| JPS62160656A (en) * | 1986-01-08 | 1987-07-16 | Nippon Telegr & Teleph Corp <Ntt> | Manufacture of positive electrode for nonaqueous electrolyte battery |
| JPS62163746A (en) * | 1986-01-13 | 1987-07-20 | Nippon Engeruharudo Kk | Platinum alloy electrode catalyst and electrode for acidic electrolyte fuel cell using same |
| US4735875A (en) * | 1986-03-24 | 1988-04-05 | W. R. Grace & Co. | Cathodic electrode |
| US4702973A (en) * | 1986-08-25 | 1987-10-27 | Institute Of Gas Technology | Dual compartment anode structure |
| US4729931A (en) * | 1986-11-03 | 1988-03-08 | Westinghouse Electric Corp. | Reforming of fuel inside fuel cell generator |
| US4802958A (en) * | 1987-03-17 | 1989-02-07 | The Standard Oil Company | Process for the electrocatalytic oxidation of low molecular weight hydrocarbons to higher molecular weight hydrocarbons |
| US4751157A (en) * | 1987-06-08 | 1988-06-14 | The United States Of America As Represented By The Secretary Of The Army | Cathode material for use in lithium electrochemical cell and lithium electrochemical cell including said cathode material |
| JPS63310574A (en) * | 1987-06-11 | 1988-12-19 | Tokyo Gas Co Ltd | Internal reforming type fuel cell |
| US4751158A (en) * | 1987-08-03 | 1988-06-14 | The United States Of America As Represented By The Secretary Of The Army | Amorphous cathode material for use in lithium electrochemical cell and lithium electrochemical cell including the amorphous cathode material |
| DE3829541A1 (en) * | 1987-09-03 | 1989-03-16 | Ricoh Kk | LEAF-SHAPED ELECTRODE, METHOD FOR PRODUCING THE SAME AND SECONDARY BATTERY CONTAINING THIS |
| US4792504A (en) * | 1987-09-18 | 1988-12-20 | Mhb Joint Venture | Liquid containing polymer networks as solid electrolytes |
| US4830939B1 (en) * | 1987-10-30 | 1996-10-08 | Mhb Joint Venture | Radiation cured solid electrolytes and electrochemical devices employing the same |
| US5037712A (en) * | 1987-10-30 | 1991-08-06 | Ultracell, Inc. | Preparation of radiation cured solid electrolytes and electrochemical devices employing the same |
| US4925752A (en) * | 1989-03-03 | 1990-05-15 | Fauteux Denis G | Solid state electrochemical cell having porous cathode current collector |
| US4925751A (en) * | 1989-04-26 | 1990-05-15 | Shackle Dale R | High power solid state electrochemical laminar cell |
-
1990
- 1990-05-10 CA CA002016517A patent/CA2016517C/en not_active Expired - Fee Related
- 1990-05-11 ES ES90305115T patent/ES2092490T3/en not_active Expired - Lifetime
- 1990-05-11 EP EP90305115A patent/EP0397523B1/en not_active Expired - Lifetime
- 1990-05-11 DE DE69028240T patent/DE69028240T2/en not_active Expired - Fee Related
- 1990-05-11 JP JP2122847A patent/JP3046323B2/en not_active Expired - Lifetime
-
1993
- 1993-11-22 US US08/155,547 patent/US5436091A/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| US5436091A (en) | 1995-07-25 |
| EP0397523A2 (en) | 1990-11-14 |
| EP0397523B1 (en) | 1996-08-28 |
| DE69028240D1 (en) | 1996-10-02 |
| DE69028240T2 (en) | 1997-01-23 |
| JP3046323B2 (en) | 2000-05-29 |
| ES2092490T3 (en) | 1996-12-01 |
| CA2016517A1 (en) | 1990-11-11 |
| JPH02312160A (en) | 1990-12-27 |
| EP0397523A3 (en) | 1991-06-12 |
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| EEER | Examination request | ||
| MKLA | Lapsed | ||
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Effective date: 20030512 |