DE19548422A1 - Composites and their continuous production - Google Patents

Description

This invention relates to continuously produced composite materials and Process for their production. The composite materials according to the invention exist from several functional materials and are, if necessary, suitable Further processing, in electrochemical cells, for example fuel cells and electrolysers.

Fuel cells are electrochemical devices in which chemical energy is converted directly into electrical energy. A particularly cheap out PEM fuel cells (Polymer Electrolyte Membrane) are the form of management The core elements are membrane electrode assemblies.

Membrane electrode units contain several functional materials and are Composite materials in the sense of this registration. Under functional materials generally electron-conducting or ion-conducting or catalytically active materials Roger that. Other functional materials are, for example, hydrophobization medium, gas transport media, catalyst supports, support structures, adhesive materials, Sealing materials or similar materials.

A membrane electrode assembly (MEA) shows the following structure ( Fig. 1): An ion conductor layer (III) is in contact on both sides with catalyst layers (II and IV), which in turn are in contact with electron conductor layers (I and V). The layers can contain several materials, have a structured structure and, if necessary, partially penetrate one another. An MEA can contain additional layers in addition to the layers mentioned above.

Composites are generally complete and functional membrane Electrode units or intermediate products for membrane electrode units, the min consist of two of the functional materials mentioned.  

PEM fuel cells are characterized, among other things, by low operation temperatures, high reliability and extensive freedom from maintenance. This are some of the advantages why such fuel cells are already considered Energy supply systems were used in space. Although PEM Fuel cells have been known for a long time and their performance has been proven up to now, they have hardly been used commercially. A broad commercial Use of PEM fuel cells are available. a. the high manufacturing costs and the fluctuating manufacturing quality of composite materials.

The costs of composite materials are u. a. through the materials used but also caused by the costly manufacturing process, the one Large number of mostly manual and difficult to automate operations that prevent rational and inexpensive industrial production.

Consistent manufacturing quality generally means that important physical and chemical properties of different materials, which originate from a production, are the same or have very little fluctuation are subject to. Consistent manufacturing quality can also mean that important physical and chemical properties at different equivalents th places of a material composite are the same or only very slight fluctuation are subject to. The relative range of variation of properties (from Material composite to material composite or within a material composite) therefore a good measure of the manufacturing quality of composite materials.

The manufacturing quality of composite materials largely depends on the manufacturing process used. Those with the known discontinuous Processed material composites often show high fluctuations in their physical and chemical properties on different equivalents Set up in the material composite. Likewise, different ones differ from one Manufacturing discontinuously manufactured material composites in their Characteristics. The with the continuous process according to the invention Manufactured material composites often have a uniform manufacturing quality very small fluctuations in their physical and chemical properties create in the material composite.  

The relative fluctuation range Δx / x of such composite properties, e.g. B. thickness of Compound material, direct current conductivity, alternating current capacity, gas permeabi lity and surface roughness, is often direct through simple measurements verifiable. The fluctuation range Δx for a material composite is one suitable continuous manufacturing process small compared to x, preferably applies Δx / x <25%, preferably Δx / x <10%, in particular Δx / x <5%. The known membrane electrode assemblies using discontinuous processes were produced, exhibit a wide fluctuation range Δx / x <25% at least one of the relevant properties mentioned above.

With regard to the intended use of composite materials in electroche mix cells, such as fuel cells or electrolysers, it has proven to be proven to be directly beneficial in such an application Use characterization; here are a variety of parameters recorded together. In some cases, however, it has also proven useful the range of fluctuation of individual parameters in a suitable measurement setup to be recorded separately.

For composite materials that represent a complete membrane electrode assembly, can, for example, characterize the performance in a fuel cell tion can be used. One gets depending on operating parameters (e.g. temperature T, gas pressures p) a current-voltage characteristic from which the Power P as a function of current density I can be taken. At the point of the maximum power P (I, T, p) / (I) = 0, such a composite material provides the electrical power P₀. The fluctuation range ΔP₀ for a material composite is with a suitable continuous manufacturing process small compared to P₀, preferably ΔP₀ / P₀ <25%, preferably ΔP₀ / P₀ <10%, in particular ΔP₀ / P₀ <5%. The well-known membrane electrode assemblies using discontinuous processes were produced, usually have a fluctuation range ΔP₀ / P₀ <25%.

For material composites, which are preliminary products of a membrane electrode unit, can, for example, the performance in a cell in an analogous manner Characterization can be used after placing it in downstream Steps in membrane electrode units. Discontinuously manufactured Composites of materials (if necessary after transfer to a membrane Electrode unit and use in a fuel cell) a range of fluctuation  of the electrical power P₀ at the maximum power ΔP₀ / P₀ <25% not yet known.

For material composites, for example, complex impedance spectroscopy can be used Characterization of uniformity can be used. Although in many Cases a complete interpretation of the spectra obtained difficult or is impossible, this method still reliably allows uniformity of composite materials to be demonstrated: with the help of impedance spectroscopy spectra obtained are quasi as a fingerprint of each material ver taken nationwide and compared with each other. This method has the advantage that even material composites that are not membrane-electrode units, directly can be examined. This method also has the advantage that the Uniformity can also be demonstrated within a composite material can, e.g. B. by disassembling a composite into small test pieces and then is measured. With a uniform manufacturing quality, the deviations are low between different samples. For discontinuously manufactured The impedance spectra of different composites are more related to materials or minor deviations from each other.

For material composites, further methods for characterizing the Uniformity. The measurements of thicknesses, gas through non-permeability, direct current or alternating current resistances and surface properties are familiar to the expert. A small fluctuation range Properties reflects a uniform manufacturing quality of the material composites contrary.

Although continuous manufacturing processes for many commercial products State of the art are known and although many membrane electrode units and their manufacturing processes are published, it has not been possible until now Membrane electrode units or their primary products with a constant Manufacturing quality continuously.

There is therefore the task of using inexpensive material composites with the same lasting manufacturing quality and suitable processes for their production  to provide.

The present invention solves these problems and relates continuously containing composite materials with constant manufacturing quality

• a. at least one layer which is ion-conducting and / or electron-conducting contains the material, and
• b. at least one layer that has one or more other functional contains materials that are in intimate contact with an electron conductive and / or an ion-conducting layer,

the relative fluctuation range of at least one composite property Δx / x, selected from the group: thickness of the composite material, direct current conductivity, AC capacity and surface roughness, <25%, preferably <10%, in particular <5%.

Furthermore, the continuously produced material composites according to the invention show if necessary after transfer to a membrane electrode assembly, in a Fuel cell a fluctuation range of electrical power P₀ am Power maximum of ΔP₀ / P₀ <25%.

The subject of this application is different composite materials, e.g. B. membrane electrode assemblies (a), membrane electrode semi-finished products (b), catalyst-coated ion conductors on both sides (c), catalyst-coated ion conductors on one side (d) and catalyst-coated electron conductors (e) ( Fig. 2) .

Furthermore, the present application relates to processes for continuous Production of composite materials with constant manufacturing quality, whereby at least one flat structure, the so-called substrate, which is a functional Contains material, continuously guided and with at least one other structure or material that contains another functional material, the so-called covering, is contacted and connected.

A continuous process in the sense of this application is still a Procedure whereby the period between the removal of two finite products is significantly shorter than the time it takes to manufacture each single finite product is needed. Also processes that are discontinuous che steps are continuous processes, provided at least one  Sub-step is carried out continuously.

By means of transport and feeding devices, for example, a flat, Structure containing substrate (substrate) continuously guided and with at least one other material (covering) containing functional material contacted and connected.

The covering can be fed continuously as a flat structure, which with the laminated, laminated, glued or otherwise suitably bonded substrate. Of the Covering can a. supplied as a solution, dispersion, paste or solid powder become and u. a. by lamination, wet coating or printing processes with the Suitable substrate are connected. Prerequisite for a continuous Manufacturing of composite materials is that at least one component as flat structure is guided, for example by means of a suitable arrangement of rolls, rollers or other transport devices.

In particular, the present application relates to the following composite materials: Containing continuously manufactured composite materials

• a. at least one centrally arranged gas-tight layer, the ion-conducting Contains material, and at least two gas-permeable layers, the electron-conducting material lien included, and
• b. at least two layers which contain catalytically active materials as further functional materials, which are in intimate contact with both an electron-conducting layer and
  also to an ion-conducting layer ( Fig. 1);
  such as
  containing continuously produced composite materials
• a. a gas-tight layer containing ion-conducting material, and a gas-permeable layer containing electron-conducting material, and
• b. a layer which contains catalytically active material as a further functional material,
  which is in intimate contact with an electron-conducting and / or ion-conducting layer ( Fig. 11a);
  such as
  containing continuously produced composite materials
• a. a gas-tight layer in the middle, the ion-conducting material contains, and
• b. two layers that contain catalytically active materials that are in intimate contact with ion-conducting material ( Fig. 10a); such as
  containing continuously produced composite materials
• a. a gas-tight layer containing ion-conducting material, and
• b. a layer that contains catalytically active material ( Fig. 9a); and
  containing continuously produced composite materials
• a. a gas-permeable layer containing electron-conducting material, and
• b. a layer that contains catalytically active material ( Fig. 8a).

Various continuous production processes are possible for the material composites mentioned. Methods are preferred in which ion conductors or electron conductors are continuously conveyed as flat, extensive structures. Such flat, extensive substrates are, for example, unreinforced or reinforced dense films which contain ion-conducting materials. Woven fabrics, nonwovens and papers which contain electron-conducting materials can also be used as flat, extensive substrates. Also suitable as flat, extensive substrates are flat finite pieces which contain electron-conducting materials, provided that they can be conveyed continuously on a flat, extensive support. Fig. 3 shows schematically examples of flat, extensive structures, which are preferably suitable for continuous conveying.

Flat structures which are particularly suitable for the continuous process according to the invention are, for example, electron conductors I or V, e.g. B. a) as an unsupported, flat extended structure (I₀ or V₀) or b) as a carrier tes, finite structure (I _T or V _T ) on a flat extended support T or ion conductor III, for example c) as an unreinforced, flat extended structure (III₀) or d) as a reinforced, flat, extended structure (III) _S with a centrally inserted support structure S ( Fig. 3).

Composites can also be used as a substrate or covering, if they are available as flat structures. Such composite materials can be separated (Continuous or discontinuous) or in one Operation can be generated continuously.

Functional materials usable according to the invention are e.g. B. ionic Materials, electron-conducting materials and catalytically active materials. Hydrophobing agents, catalyst supports, support structures, flat supports, adhesive materials or sealing materials and other similar Functional materials can be included in the composite materials.

Electronically conductive materials are used for the claimed composite materials Carbon in a conductive modification, preferably as graphite, carbon black, activated carbon, Vulcan black, carbonized or graphitized powder, granules, papers, fibers, fleeces, Felts, fabrics and composite structures or metals, preferably stainless steel, nickel and titanium, preferably as powder, granules, papers, fibers, nonwovens, fabrics, Sintered plates or combinations thereof are used.

If necessary, the electron-conducting materials or the material composites that contain electron-conducting materials, a conditioning subject. Such conditioning can serve to establish contact between to improve electron-conducting particles or structures and thereby the lower electrical resistance, permeability to gases or water too increase or the connection to catalytically active materials or ion-conducting Optimize materials. Such a conditioning step can u. a. Press, Annealing, watering, swelling and drying include.  

Electronically conductive materials are often called porous fabrics or thin Layers for gas-permeable structures used in composite materials. Prefers For example, fabrics are used that have an electrical conductivity <0.01 µm and have a porosity of 10% to 90%, the one allows sufficient diffusive gas transport in electrochemical applications.

Electronically conductive materials are often also called powders or granules used, provided they have electrical conductivity and good in the composite network Have gas diffusion properties. Electronically conductive materials can a. can be used as fluid preparations (e.g. as dispersions). Electron wire materials can be covered with a conductive protective layer (e.g. made of gold) be covered.

Catalytically active materials are e.g. B. Substances that (directly or after chemical conversion) have the ability to catalyze electrochemical reactions. A material that does not yet have a catalytic effect itself, but that acts as a catalyst after chemical conversion (e.g. reduction), is also a catalytically active material. Preferred catalytically active materials are those which, after suitable conditioning, the reactions H₂ 2 H⁺ + 2 e⁻ and / or 2 e⁻ + ½ O₂ O ^2- and / or H₂ + ½ O₂ H₂O and / or CH₃OH + H₂O 3H₂ + Catalyze CO₂. Such catalytically active materials often contain elements of subgroups 1, 2 and 8 of the periodic table as well as elements of other groups, in particular Pt, Ir, Cu, Ag, Au, Ru, Ni, Zn, Rh, Sn, Re, Ti, W , and Mon.

Catalytically active materials for composite materials can be supported and unsupported catalysts, colloidal systems and catalyst precursors contain. Catalytically active materials can be metals, oxides, alloys or Mixed oxides and acids, salts or complexes contain.

It may be necessary to use catalytically active materials as well as composite materials contain catalytically active materials to be subjected to conditioning. A such conditioning can e.g. B. serve to change oxidation levels Precipitation of the catalyst, converting it to its active form, from surface coverings genes and potential toxins, the accessibility or activity of the Increase catalyst or the connection to electron-conducting or ion-conducting optimize materials. Such a conditioning step can u. a. Reduction, oxidation, chemical or electrochemical deposition, tempering,  Include watering or drying.

Composites, the catalytically active material based on elements of the eighth Subgroup based, contain, often have a concentration of the catalyst on the 0.01 to 4.0 mg element of the 8th subgroup per cm² of coating area corresponds. Here, the upper limit of the assignment with catalytically active Material is given by the material price, the lower limit is given by the kata lytic activity set. Because of the often high price of catalysts a locally targeted introduction of the catalytically active material in one Material composite advantageous, where a close connection of a high Percentage of the catalytically active material in electron-conducting and ion-conducting material is guaranteed. Therefore, preparations contain the contain catalytically active material, often also ion-conducting and / or electrical tron-conducting material.

Catalytically active materials can u. a. as fluid preparations (e.g. Dispersio solutions) can be used.

Ion-conducting materials are substances that alone or in the presence of water, an aqueous electrolyte, an acid or an alkali, the ability to Have transport of ions. Also a material that alone or no allows low ion transport, but after swelling in water or another suitable substance, e.g. B. H₃PO₄ or H₂SO₄, is capable of ion transport, is thus an ion-conducting material. The same goes for a material that is in a salt form relevant conductivities are present and only after conversion into an acid form for specific ions.

Ion-conducting materials that are used, among other things, for the construction of the gas-tight, ion-conducting layer are suitable, for example, contain polymers that are ionic have dissociable groups. Ionic materials preferably contain Polymers that have disassociable acidic groups, either covalent bound functional groups such as -SO₃M, -PO₃MM ′, -COOM u. a. (M, M ′ = H, NH₄, metals, especially alkali and alkaline earth metals) or acids as sources solvents such as H₃PO₄ or H₂SO₄.  

Ion-conducting materials preferably contain polyarylenes, with functional ones Groups such as -SO₃H (see formula (I)). Particularly preferred polyarylenes have a polyether ketone, a polyether sulfone or a polyarylene sulfide as the main chain on. Perfluorinated polymers with a sulfonic acid group are also preferred side chains used. Polybenzimidazoles (PBI) are also preferred contain dissociable acidic groups (e.g. PBI swollen with H₃PO₄). Ion conducting de Materials also preferably contain polymer mixtures that at least contain one of the above-mentioned polymers.

X = (in any order) O, CO, SO₂, SO, S, C (CH₃) ₂, O (CO), NH (CO)
Y = (in any order) H, SO₃M, PO₃MM ′, COOM
M, M ′ = H, NH₄, metals.

It may be necessary to use ion conducting materials as well as films or material composites that contain ion-conducting materials for conditioning subject. Such conditioning can serve to be specifically preferred Adjust water, electrolyte, ion, solvent or swelling agent contents or the connection to catalytically active materials or electron-conducting Optimize materials.

Such a conditioning step can be the entry or the removal of Represent auxiliary substances (e.g. water, solvents, swelling agents), for example (A) by steam treatment, by spraying more suitable  Fluids, by squeegees or slit nozzle application of suitable fluids or by Dip in a suitable conditioning bath or (B) by drying or through extractive exchange (for example coupled with phase inversion). Of the Conditioning step can also be a thermal treatment, e.g. B. heating in Convection chambers, irradiation with IR or MW radiation or diving into one Bathroom, include.

Conditioning can also be used to remove ion-conducting materials from to convert a salt form into the acid form or vice versa from the acid in a salt form. Such a conditioning step preferably includes that Dipping in acidic, alkaline or saline solutions. The in this and in The conditioning steps described in the previous paragraph can be done individually or in combination with each other.

Ion conducting materials can a. as fluid preparations (pastes, solutions or dispersions or aerosols based on solutions or dispersions) be used. Suitable auxiliaries can be water and aprotic dipolar solvents (e.g. N-methylpyrrolidone (NMP), dimethylformamide (DMF), Dimethylacetamide (DMAc), dimethyl sulfoxide (DMSO)) or acids (e.g. sulfur acid).

For example, fluorine-containing polymers (e.g. Polytetrafluoroethylene (PTFE), CTFE) or silicones are used. Hydrophobization materials can be used as fluids (e.g. dispersions).

Catalytically active materials can u. a. Catalyst carrier included. Catalyst In addition to a high specific surface area, carriers often have a high porosity with a defined pore size distribution. To ensure a good connection of the catalytic active material to ion-conducting material and electron-conducting material porous carbon particles (e.g. Activated carbon or Vulcan black, e.g. B. ®XC-72 and ®XC-72R from E-TEK) used. These can U. also contain ion-conducting material.

Fabrics or nonwovens of polymers are used as support structures. Before are fed monofilament fabrics made of high-performance polymers such. B. polyarylenes, used. But also nonwovens or microporous membranes from other polymer materials  materials such as B. polyethylene terephthalate (PET) or polytetrafluoroethylene (PTFE) are often suitable.

Films, fabrics or nonwovens of polymers are used as support structures. Films, fabrics or nonwovens made of carbon are also used as support structures or metals used. Films made of PET or polyamide (e.g. Mylar®), monofilament made of PET or high-performance polymers (e.g. Polyethe retherketone (PEEK)) is used. Aluminum foils are also preferred or stainless steel or thin-mesh stainless steel mesh.

Adhesive materials often contain solvents and / or swelling agents for ion conducting materials. Adhesives can optionally be used as a liquid or be used in vapor form. Adhesives also often contain ion-conducting agents Materials. Adhesives can be used as fluid preparations, i.e. as pastes, Solutions and dispersions and as aerosols of solutions or dispersions, be used.

Hydrophobic polymers are often used as sealing materials. Prefers are fluorinated polymers such. B. PTFE, and also cross-linked or crosslinkable thermoplastic polymers, such as. B. polysiloxanes or polyurethanes. Sealing materials can be sheet-like structures (e.g. die-cuts), fluids (e.g. Solutions, pastes or dispersions) or in bulk.

In this application, auxiliaries are understood to be substances which, as solvents, Dispersing agents, swelling agents, plasticizers, non-solvents, release agents and the like find use during the manufacturing process. Generally will they only temporarily d. H. for shaping, for setting physical properties shaft or used to achieve a suitable composite. Tools can remain in the resulting composite (e.g. water) or completely or almost completely removed (e.g. precipitant).

A number of manufacturing processes are suitable using composite materials continuous manufacturing quality. Here is a Continuously conveyed substrate and provided with a covering.  

The substrate is preferably used as a flat, extensive structure, preferably with a thickness in the range from 5 μm to 5 mm, in particular 10 μm to 1 mm, a width in the range of 5 cm to 300 cm, preferably 10 cm to 100 cm, and a length of well over 300 cm.

Large substrates ( Fig. 4 (a)) or extensive flat structures, e.g. B. as a carrier, on which flat finite structures are arranged ( Fig. 4 (b)).

For example, on a flat, extensive support, in regular Arrangement of flat finite pieces containing electron-conducting material, be upset.

The flat finite structures have a thickness of 5 µm to 5 mm, preferably from 10 μm to 1 mm, their width is 5 cm to 300 cm, preferably 10 cm to 100 cm, their length is 5 cm to 300 cm, preferably 10 cm to 100 cm. The flat, extensive carrier has a thickness of 5 μm to 5 mm, preferably from 10 µm to 1 mm, its width is 5 cm to 300 cm, preferably 10 cm to 100 cm, its length is significantly more than 300 cm.

The product can be removed as a flat, extensive material composite, another continuous coating process or after a dicing process, e.g. B. punching or cutting, as a variety of flat finite material composites arise.

The covering can be fed continuously as a flat structure and with the substrate get connected.

The covering is used, for example, as a flat, extensive structure, i. H. his Thickness is 5 µm to 5 mm, preferably 10 µm to 1 mm, its width is 5 cm to 300 cm, preferably 10 cm to 100 cm, its length is significantly more than 100 cm. Furthermore, the covering can be a flat, extensive structure, on the flat finite one Structures made of functional materials are used. The flat In this case, finite structures preferably have a thickness of 5 m to 5 mm on, in particular from 10 microns to 1 mm, their width is 5 cm to 100 cm, preferred 10 cm to 60 cm, their length is 5 cm to 100 cm, preferably 10 cm to 60 cm. The flat, extensive carrier has a thickness of 5 μm to 5 mm, preferably from 10 μm to 1 mm, its width is 5 cm to 100 cm, preferably  10 cm to 60 cm, its length is significantly more than 100 cm.

If the covering is supplied as a flat structure, it can with the flat substrate under the influence of increased pressure and / or elevated temperature and / or adhesive laminated, glued or otherwise suitably connected. Contains the topping and that Substrate-like finite structures, the two become positionally precise, for example merged.

The coating can be supplied as a fluid or powdery preparation or continuously and be connected to the substrate. The preparation can be 100% Functional material exist or contain this between 1% and 99%. As a fluid apply liquid, low-viscosity and liquid, viscous and liquid or pasty, highly viscous preparation forms (solutions and dispersions) and, if necessary Spray droplets or aerosols (from solutions and dispersions) as well as given if gases or vapors.

The covering is used, for example, as a solution or dispersion. A low-viscous Solution or dispersion is, for example, by wet coating, such as. B. spraying, applied. For example, a viscous solution or dispersion becomes wet coat such. B. doctor blade or slot nozzle application. It can Covers or masks are used so that the fluid preparation only in selected areas of the substrate is applied.

The covering is used, for example, as a paste or solution or dispersion. On such fluid is, for example, by printing techniques such as high, low, flat or Screen printing applied. It can be shaped printing tools or covers or Masks are used so that the fluid preparation only in selected ones Areas of the substrate is printed.

The covering is used, for example, as a solid powder and on a liquid wetted or swollen substrate applied by sanding. It can Covers or masks are used so that the powdery preparation only is applied in selected areas of the substrate.

If the coating is supplied as a fluid or powder, it can be used with the flat substrate suitably connected under the influence of increased pressure and / or elevated temperature will.  

A substrate can be coated on one or both sides with a covering. Fig. 5 shows schematically the possibilities of the order. In the continuous coating method according to the invention, the coating can be carried out in three different ways ( Fig. 5):

• a) one-sided coating of the substrate with coating,
• b) two-sided two-stage coating (possibly with intermediate conditioning steps),
• c) two-sided single-stage coating.

Among others, the following techniques can be used in conjunction with the listed Functional materials for the continuous production of composite materials can be used:

Catalytically active material can be applied in fluid or powdery preparations or can be made as a flat structure as part of a material composite. Preparations can contain catalytically active material as supported catalysts, unsupported catalysts, catalyst precursors or mixtures thereof. Catalytically active material can include
by sputtering, chemical vapor deposition, physical vapor deposition or plasma deposition etc. of metal, by wet coating, such as. B. doctor blades or slot nozzle application of fluid preparations that contain catalytically active material by wet coating, such as. B. spraying of fluid preparations containing catalytically active material, by printing techniques (letterpress, gravure, flat, screen printing) with fluid preparations containing catalytically active material, by chemical deposition or precipitation from solutions containing catalytically active material contained, by electrochemical deposition from solutions which contain catalytically active material, by sanding with powdery preparations which contain catalytically active material, or by laminating a flat structure which contains catalytically active material,
possibly applied in a continuous manner to surfaces or in porous structures of a substrate using elevated pressure and / or elevated temperature and / or an adhesive. Here, aids can be used, which can be removed by evaporation or extractive exchange.

Catalytically active material can be in flat structures (substrate or covering) be included and continuously managed. The flat structure is prefers a material composite itself and can be extended or flat to be finite; it can be supported or unsupported. The flat structure can contain a support structure. The microstructure of the flat structure carries the The fact that the catalytically active material may have a have intimate contact with ion-conducting and electron-conducting material should, as well as, if appropriate, transport and removal of reactants in one allows electrochemical cell.

Ion-conducting material can be applied in fluid or powdery preparations or can be carried out as a flat structure. Ion-conducting material can include
by wet coating, such as. B. doctor blade or slot nozzle application of fluid preparations containing ion-conducting material,
by wet coating, such as. B. spraying of fluid preparations containing ion-conducting material,
through printing techniques (high, low, flat, screen printing) with preparations containing ion-conducting material,
by laminating a flat structure which contains ion-conducting material,
possibly applied in a continuous manner to surfaces or in porous structures of other materials using elevated pressure and / or elevated temperature and / or an adhesive or by extrusion of fusible ion-conducting material. Liquids can be used as aids here, which can be removed by evaporation or extractive exchange, among other things.

Ion-conducting material can be contained in flat structures (substrate or coating) be and be managed continuously. The flat structure can be flat  to be extended or finite; it can be supported or unsupported. The flat structures can contain a support structure, which is preferably in the center of the ion-conducting material is introduced. The microstructure of the flat structure, if it is to function as layer III in the material composite, this fact Calculation that layer III has a high diffusion resistance for gases should have, so should be largely gas-tight.

Electron-conducting material can be applied in fluid or powdery preparations or can be carried out as a flat structure. Electronically conductive material can include
by wet coating, such as. B. doctor blade or slot nozzle application, of dispersions containing electron-conducting material,
by wet coating, such as. B. spraying of dispersions containing electron-conducting material,
by printing techniques (high, low, flat, screen printing) with fluid preparations containing electron-conducting material, or
by laminating a flat structure which contains electron-conducting material,
Possibly be applied to surfaces or in porous structures of other materials in a continuous manner using elevated pressure and / or elevated temperature and / or an adhesive. Liquids can be used as aids here, which can be removed by evaporation or extractive exchange, among other things.

Electron-conducting material can be used in flat structures (substrate or covering) be included and continuously managed. The flat structure can be extensive or finite; it can be supported or unsupported be. The microstructure of the flat structures, provided that they are in the material composite Layer I or V is to function takes into account the fact that the layers I and V should have a low transport resistance for gases, so should be gas permeable.

Hydrophobing material can e.g. B. applied in fluid preparations. Hydrophobing material can include
by wet coating, such as. B. squeegees or slot nozzle application, of fluids that contain hydrophobic material,
by wet coating, such as. B. spraying, of fluids containing hydrophobic material, or
by printing techniques (high, low, flat, screen printing) with preparations that contain hydrophobic material,
applied to surfaces or in porous structures of other materials in a continuous manner. Liquids can be used as aids here, which can be removed by evaporation or extractive exchange, among other things.

Water-repellent material can be contained at different points in a composite. Fig. 6 shows various surfaces that can contain water repellents using the example of a membrane-electrode unit. Thus, water repellents (H) can be contained in layers I, II, III, IV, V or in the surfaces of such layers, or can partially penetrate the layers (H _I outside on layer I, H _{I / II} between layers I and II , H _{II / III} between layers II and III, H _{II / IV} between layers III and IV, H _{IV / V} between layers IV and V, H _V outside on layer V).

Support structures may be in flat structures that are ion-conducting or contain electron-conducting material used. Support structures can with ion-conducting or electron-conducting materials according to the above Techniques.

Support structures are u. a. used to make flat finite structures that e.g. B. contain electron-conducting material, continuously as a flat extended To be able to promote structures. Support structures can be finite with flat Formations, the z. B. contain electron-conducting material, according to the above Techniques.

Flat structures that contain support or support structures can be separated (Continuous or discontinuous) or in one Operation can be generated continuously.

Adhesive can be brought into contact with materials as a fluid. The adhesive can include
by immersing in baths containing adhesives, or
by vapor deposition with fluids (e.g. solvents or swelling agents)
by wet coating, such as. B. doctor blades or slot nozzle application, of fluid preparations containing adhesives,
by wet coating, such as. B. spraying, of fluid preparations containing adhesives,
through printing techniques (high, low, flat, screen printing) with fluid preparations containing adhesives,
continuously brought into contact on surfaces or in porous structures of other materials.

Hydrophobic polymers are often used as sealing materials. Prefers are fluorinated polymers such. B. PTFE, and also cross-linked or crosslinkable thermoplastic polymers, such as. B. polysiloxanes or polyurethanes. Sealing materials can be used as die cuts, pastes, solutions, dispersions or be used in substance.

The sealing material can be applied as a fluid preparation or as a flat structure. The sealing material can include
by wet coating, such as. B. squeegees or slot nozzle application, of fluids containing sealing material,
by wet coating, such as. B. spraying of fluids containing sealing material,
by printing techniques (high, low, flat, screen printing) with preparations containing sealing material, or
by introducing a flat structure that contains sealing material,
possibly applied to other materials in a continuous manner using elevated pressure and / or elevated temperature and / or an adhesive. Liquids that can be removed by evaporation or extractive exchange can be used as an aid.

Flat structures can the sealing material in the form of finite flat Die cuts included. The sealing material can be used in a targeted form partially overlap adjacent functional materials. Sealing material can be contained at different points in a material composite.

Fig. 7 shows the example of a membrane electrode assembly (MEA) different surfaces that may contain sealing material (schematic representation of some surfaces a) of a membrane electrode assembly that can be provided with sealing material (D); b) D _I outside on layer I, D _V outside on layer V; c) D _{I / III} between layers I and III, D _{III / V} between layers III and V; possible positions of layers II and IV are indicated). The sealing layers can partially overlap with adjacent layers.

Auxiliaries, ie solvents, dispersants, swelling agents, plasticizers, non-solvents, release agents, can be introduced by the above-mentioned techniques. Aids can
by drying (evaporation or vacuum evaporation),
through extractive exchange (possibly with phase inversion) or
can be removed from composite materials by a combination of both methods.

Fig. 8 shows schematically a) a catalyst-coated electron conductor and b) a preferred manufacturing process. Such material composites consisting at least of a gas-permeable layer (I or V) which contains electron-conducting material and of a layer (II or IV) which contains catalytically active material (in intimate contact with electron-conducting material of layer I or V) can by continuous processes with uniform manufacturing quality can be produced. Production methods are preferred in which a flat structure which contains electron-conducting material is guided as a substrate and is coated on one side with a coating which contains catalytically active material.

Fig. 9 shows schematically a) a one-sided catalyst-coated ion conductor and b) a preferred manufacturing process. Such material composites consisting at least of a gas-tight layer (III), which contains ion-conducting material, and of a layer (II or IV), which contains catalytically active material (in intimate contact with the ion-conducting material of layer III), can be obtained by continuous processes with uniform Manufacturing quality can be manufactured. Production methods are preferred in which a flat structure which contains ion-conducting material is guided as a substrate and is coated on one side with a covering which contains catalytically active material.

Fig. 10 shows schematically a) a catalyst conductor coated on both sides with catalyst and b) a preferred manufacturing process. The composition of layers II and IV can be different. Such material composites consisting at least of a gas-tight layer (III), which contains ion-conducting material, and of two layers (II and IV), each containing catalytically active materials, which are in intimate contact with the ion-conducting material of layer III, can by continuous processes with uniform manufacturing quality can be produced. Production methods are preferred in which a flat structure which contains ion-conducting material is guided as a substrate and is coated on both sides with coatings which each contain catalytically active materials.

Figure II shows schematically a) a semi-finished membrane electrode and b-g) six preferred manufacturing processes. Are material composites as a substrate or topping, they can be used separately or in one operation getting produced. Such composite materials consisting of at least one gas-tight layer (III), which contains ion-conducting material, from a gas through allowable layers (I or V), which contains electron-conducting material, and from a layer (II or IV) that contains catalytically active material that is both in intimate contact with the electron-conducting layer as well as with the ion-conducting the layer (III) is located by continuous methods with the same moderate manufacturing quality. Manufacturing is preferred here procedures in which the substrate and covering are promoted as flat structures and be connected to each other; a flat structure contains ion-conducting Material, the other electron-conducting material. In a particularly preferred Embodiment an adhesive is used, the catalytically active material contains. Also preferred are manufacturing processes in which a flat substrate, which contains electron-conducting material, as a coating a fluid  is applied, which contains ion-conducting material. Are also preferred Here manufacturing processes in which a substrate as a flat structure is promoted, which contains electron-conducting material, on which only a coating that contains catalytically active material, and later a coating, the ion-conducting Contains material to be applied.

Fig. 12 shows schematically a) a membrane electrode assembly and bh) seven preferred manufacturing processes. If composite materials are used as a substrate or covering, they can be produced separately or in one operation. The composition of all layers can be different. Such material composites consisting at least of a gas-tight layer (III), which contains ion-conducting material, of two gas-permeable layers (I and V), which contain electron-conducting materials, of two layers (II and IV), each containing catalytically active materials, which are both in intimate contact with an electron-conducting layer (I or V) and with the ion-conducting layer (III) can be produced by continuous processes with uniform manufacturing quality. Manufacturing processes are preferred in which the substrate and at least one covering are conveyed as flat structures and connected to one another; one flat structure contains ion-conducting material, at least one other contains electron-conducting material; at least one flat structure itself already represents a composite material in the sense of the present application. Also preferred here are production processes in which flat structures are connected using an adhesive which contains catalytically active material; the flat structure to be introduced in the middle contains ion-conducting material, two further flat structures contain electron-conducting material. Also preferred here are production processes in which a substrate is conveyed as a flat structure which contains electron-conducting material, to which coatings which contain catalytically active material are applied first, and coatings which contain ion-conducting materials later.

In the continuous production of composite materials, this is among other things Process with which the covering is applied to the substrate, quality determining. In the continuous production of composite materials with Uniform manufacturing quality are the following parameters for the different Particular attention should be paid to procedural steps.  

For example, the spraying process depends on the amount Fluid or aerosol to be applied per area of the substrate Nozzle type, the nozzle geometry, the distance nozzle to substrate, the substrate conveying speed, the composition of the fluid to be sprayed, the active same differential pressure and other parameters must be carefully selected. Its viscosity depends on the composition of the fluid to be sprayed and thus the preferred type of nozzle and its operating parameters. At the Applying fluids to substrates can be single-substance or two-substance nozzles be used. Suitable nozzle geometries are u. a. Swirl chamber nozzles, Hollow-cone or full-cone nozzles, flat jet nozzles, impact nozzles and rotary nozzles dust. It can spray angles between 30 and 160, volume flow rates of the fluid from 100 ml / h to 100 I / h and average droplet diameter of 5 µm up to 1 mm. Average droplet diameters of less than 100 µm. Static pressures in front of the nozzle or differential pressures above the The nozzle is between 0.2 bar and 100 bar, preferably between 1 bar and 5 bar. Rotary atomizers are suitable for atomizing viscous fluids. At Disc diameters of 2-50 cm can be speeds from 60 to 1000 rpm will be realized.

For example, for wet coating with slot nozzles, doctor blades, etc. that depending on the amount of pressure preparation per surface of the substrate to be applied, the type of coating (e.g. slot nozzle, squeegee, etc.), the Substrate conveying speed, the composition of the coating preparation and other operating parameters (e.g. slot width, temperature, etc.) must be selected. Depending on the composition of the preparation their viscosity and thus the preferred type of wet coating and their Operating parameters. The preparation is used, for example, as a paste or solution or dispersion used. Static pressures in front of the nozzle or differential pressures The nozzle is between 0.01 bar and 10 bar. It will make you tion thicknesses from 1 µm to 300 µm, preferably from 5 µm to 100 µm. As Slot nozzles according to the invention are suitable nozzles that have a width in the range of 0.1 up to 5 m and have a slot width in the range of 10 to 1000 mm. The substrate becomes wet coating either in the horizontal direction (above or below the Nozzle) or in the vertical direction (ascending or descending) at the slot nozzle passed by. If the substrate is conditioned on both sides, the Applying the covering accordingly by carrying out the substrate  between two slot nozzles or by an immersion bath with suitable wipers respectively. Alternatively, the substrate can be coated by using a squeegee is led past. The width of the doctor blade is preferably in the range from 0.1 to 5 m with a slot width in the range of 5 to 500 mm. The substrate conveying speed is between 0.5 mm / s to 10 m / s, preferably 5 mm / s to 1 m / s.

For example, the printing process depends on the quantity Printing preparation to be applied per surface of the substrate, the type of printing, the substrate conveying speed, the composition of the print preparation and other operating parameters (e.g. temperature, contact pressure, contact time, etc.) must be selected. Depend on the composition of the print preparation their viscosity and thus the preferred type of printing and their operating parameters. The Print preparation is used, for example, as a paste or solution or dispersion. Such a preparation is, for example, by printing techniques such as high, flat, Gravure or screen printing applied.

The print preparation can e.g. B. with the help of rollers locally unselective on the substrate be transmitted. The print preparation can u. a. with the help of a printing form locally be selectively transferred to the substrate. The preparation of pressure is by the Transfer printing form to the substrate possibly using an intermediate switched elastic roller or surface. Rotary printing techniques are preferred, which allow continuous printing with finite covering surfaces. The Substrate conveying speed is up to 10 m / s, preferably up to 0.5 m / s.

The printing preparation can be done with the help of inking rollers on raised surfaces a printing form (high pressure). The printing form can be made of metal (e.g. Stainless steel) or plastics (e.g. Nyloprint, from BASF; Dycril, from DuPont). Likewise, the print preparation can be wetted with the help of inking rollers Surfaces of a printing form are applied (planographic printing). The printing form can be made Metal or plastics exist.

It is also possible for the printing preparation to be introduced into the depressions of a printing form with the aid of rollers and doctor blades (gravure printing). Here, too, the printing form can consist of metal and have depressions of 3 to 60 nm in a density of 40 to 80 cm ^-2 .

Other alternatives are e.g. B. that the pressure preparation with the help of rollers on a Printing form is applied (screen printing). The printing form can be made of silk, synthetic fiber or metal wire mesh, covering non-printing parts.  

Catalytically active material can U. can be applied as metal, the metallization taking place on dry, physical paths. Metal can be evaporated onto a substrate in vacuo at a pressure of approx. 10 ^-5 -10 ^-3 -1 mbar. Finely distributed metal is generated by a high voltage discharge from a cathode or by a plasma from a suitable source and condensed on the substrate.

Furthermore, catalytically active material can be applied as metal, the Metallization takes place via wet, chemical processes. These can a. Precipitations and include reductions. As a reducing agent u. a. Formaldehyde, glyoxal, Hydrazine, sodium hypophosphite, diethylaminoborane in question.

An additional possibility is the application of the catalytically active material as a precipitate, which the metals in the form of compounds, salts, acids, Contains bases, complexes.

Likewise, the catalytically active material in mixtures with ion-conducting and / or with electron-conducting materials or combinations with both be applied (inktechnics).

In the continuous production of composite materials, this is among other things Processes of how covering and substrate are connected, quality determining. The connection may be done by lamination or by Pressing and / or by gluing.

When laminating, the substrate and covering are arranged in an arrangement of rolls and Rolls connected together. Parallelized pairs of rollers are particularly suitable with adjustable distance. The lamination is done with suitable prints, preferably as in the range of 10⁷ to 10¹² Pa, in particular 10⁸ to 10¹⁰ Pa and suitable temperatures, preferably in the range from 5 to 300 ° C., in particular 25 to 200 ° C. It should be noted that the contact pressure when using Rolls is often heavily dependent on the roll material and diameter. Of the The diameter of the rolls used according to the invention is preferably in the range from 0.1 to 2 m.

When pressing, the substrate and coating are arranged in an arrangement of pressure transducer and parallelized counterpart connected together. Presses can be discontinuous  or fed and emptied continuously; as opposed to laminating during the actual pressing process there is no transport of substrate and covering instead of. The pressing is carried out with suitable prints, preferably in the range of 10⁷ up to 10¹² Pa, in particular 10⁸ to 10¹⁰ Pa and at suitable temperatures, preferably in the range from 5 to 300 ° C, in particular 25 to 200 ° C.

In lamination as in pressing, the substrate and / or covering can be suitably Conditioning steps contain solvents or swelling agents and thereby be partially plasticized. Adhesives can also be used when laminating or pressing be placed between the substrate and the covering.

Adhesives cause bodies to stick together through adhesion and cohesion get connected. Fluid adhesives can be made by various techniques in Brought into contact with the substrate: dipping, vapor deposition, wet coating, To press. Depending on the amount of adhesive per surface area of the substrate the type of application, the substrate conveying speed, the composition of the adhesive and operating parameters (drying temperature, drying time, contact pressure, contact time etc.) can be selected. The Adhesive preparation is used, for example, as a paste or solution or dispersion. The preferred application technique depends. a. on the viscosity of the preparation. For Relatively low-viscosity adhesives are suitable application methods for spraying techniques.

The process according to the invention for the continuous production of material combined has a number of advantages: the economic advantage of claimed process is particularly reflected in the low manufacturing cost reflected, the technical advantage on the other hand especially in the uniform manufacturing quality of the material combinations obtained can be seen.

The material composites produced according to the invention are suitable due to their high Manufacturing quality especially for use in electrochemical cells, preferably in fuel cells and electrolysers. The use of the Compounds preferred in electrolytic capacitors.

Claims (41)

1. Continuously manufactured material composites with even
Containing manufacturing quality

• a. at least one layer containing ion-conducting and / or electron-conducting material,
• b. at least one layer containing one or more other functional materials which are in intimate contact with an electron-conducting

and or
ion-conducting layer,
the relative fluctuation range of at least one composite property Δx / x, selected from the group: thickness of the composite material, direct current conductivity, alternating current capacity and surface roughness, is <25%. 2. Continuously produced composite materials according to claim 1, characterized records that this, if necessary after transfer into a membrane Electrode unit, a swan in a fuel cell at maximum power kungsbreite the electrical power ΔP₀ have, which is small compared to the electrical power P₀ and preferably ΔP₀ / P₀ <25%. 3. Continuously produced composite materials according to claim 1 and / or 2 containing

• a. at least one centrally arranged gas-tight layer which contains ion-conducting material and at least two gas-permeable layers which contain electron-conducting materials, and
• b. at least two layers which contain, as further functional materials, catalytically active materials which are in intimate contact both with an electron-conducting layer and with an ion-conducting layer.

4. Continuously produced composite materials according to claim 1 containing

• a. a gas-tight layer which contains ion-conducting material and a gas-permeable layer which contains electron-conducting material, and
• b. a layer which contains, as a further functional material, catalytically active material which is in intimate contact with an electron-conducting and / or ion-conducting layer.

5. Continuously produced composite materials according to claim 1 containing

• a. a centrally arranged gas-tight layer which contains ion-conducting material, and
• b. two layers that contain catalytically active materials and both are in intimate contact with ion-conducting material.

6. Continuously produced composite materials according to claim 1 containing

• a. a gas-tight layer containing ion-conducting material, and
• b. a layer that contains catalytically active material.

7. Continuously produced composite materials according to claim 1 containing

• a. a gas-permeable layer containing electron-conducting material, and
• b. a layer that contains catalytically active material.

8. Continuously manufactured composite materials according to at least one of the Claims 1 to 6, characterized in that the gas-tight, ion conducting de layer contains a polymer with dissociable groups. 9. Continuously produced composite materials according to claim 8 thereby characterized in that the gas-tight, ion-conducting layer of a polymer contains the group of sulfonated polyarylenes. 10. Continuously produced composite materials according to claim 8, characterized characterized in that the gas-tight, ion-conducting layer with a polymer a polyether ketone, polyether sulfone or polyphenylene sulfide main chain contains. 11. Continuously manufactured composite materials according to at least one of the Claims 3, 4 or 7, characterized in that the electron-conducting Layer of metals or carbon in conductive modification or mixtures contains from this.   12. Continuously produced composite materials according to claim 11, characterized characterized in that the gas-permeable, electron-conducting layer Papers, fibers, nonwovens, fabrics, powders, granules, felts or sintered plates Made of metal, especially stainless steel, nickel, titanium, or carbon in conductive modification, in particular graphite, activated carbon, carbon black, or Contains mixtures thereof. 13. Continuously produced composite materials according to at least one of the Claims 3 to 7, characterized in that the catalytically active Material at least one element of the 1st, 2nd or 8th subgroup of the Periodic table, in particular Pt, or compounds of such Contains element. 14. Continuously produced composite materials according to at least one of the Claims 3 to 7, characterized in that the catalytically active Material at least one supported catalyst and ion-conducting Contains material. 15. Continuously produced composite materials according to at least one of the Claims 3 to 7, characterized in that the catalytically active Material contains a supported catalyst, the support of which is ion-conducting Contains material. 16. Process for the continuous production of material composites with constant manufacturing quality, with at least one flat structure, which contains ion-conducting or electron-conducting material, continuously performed and contacted with at least one other structure or material and is connected, which contains another functional material. 17. The method according to claim 16, characterized in that the relative Fluctuation range of the compound properties Δx / x, selected from the Group: thickness of the composite material, direct current conductivity, alternation current capacity and surface roughness in the material obtained connected <25%.   18. The method according to claim 16, characterized in that the obtained Composites, if necessary after transfer into a membrane Electrode unit, in a fuel cell at the maximum power Have fluctuation range of electrical power ΔP₀, which is small compared to the electrical power P₀ and preferably ΔP₀ / P₀ <25%. 19. The method according to claim 16, characterized in that the further Functional material is an electron or ion conducting and / or catalytic is active material. 20. The method according to claim 16, characterized in that the flat, continuously guided structures contains ion-conducting material. 21. The method according to claim 16, characterized in that the flat, continuously guided structures contains electron-conducting material. 22. The method according to claim 16, characterized in that at least one Composite material according to claims 1, 2 or 4 to 7 as a flat Structure is used. 23. The method according to claim 16, characterized in that two planar extensive structures continuously promoted and connected will. 24. The method according to claim 16, characterized in that three planar extensive structures continuously promoted and connected will. 25. The method according to at least one of claims 23 or 24, characterized characterized in that two material composites according to claims 4 and / or 7 can be used as flat structures. 26. The method according to at least one of claims 24 or 25, characterized characterized in that two material composites according to claims 4 and / or 7 with the central introduction of a gas-tight flat Formed, which contains ion-conducting material, combined into a composite  will. 27. The method according to at least one of claims 24 or 25, characterized characterized in that two material composites according to claims 4 and / or 7 with the central introduction of a composite material Claim 5, to be combined into a network. 28. The method according to claim 16, characterized in that at least one flat, continuously guided structure by wet coating, Spraying or printing is contacted with a fluid that is another Contains functional material. 29. The method according to claim 28, characterized in that for coating tion solutions or dispersions containing one or more catalytically active Contain materials used. 30. The method according to claim 16, characterized in that at least two flat structures by laminating and / or using a Adhesive can be combined into a composite. 31. The method according to claim 30, characterized in that the adhesive, contains ion-conducting and / or catalytically active material. 32. The method according to claim 16, characterized in that a flat A structure containing ion-conducting material on one or both sides a preparation is contacted and connected, the catalytically active Contains material. 33. The method according to claim 16, characterized in that a flat Structure containing electron-conducting material by sputtering, Chemical Vapor deposition, physical vapor deposition or plasma deposition with another functional material is contacted. 34. The method according to claim 16, characterized in that a flat Structure containing electron-conducting material with a paste, solution, Dispersion or an aerosol containing catalytically active material, is contacted and connected.   35. The method according to claim 34, characterized in that the elec tron-conducting material contains carbon in a conductive modification. 36. The method according to claim 34, characterized in that the elec tron-conducting material contains metal, preferably stainless steel, nickel, titanium. 37. The method according to at least one of claims 34 to 36, characterized characterized in that the flat structure with a paste, a solution, a dispersion or an aerosol containing catalytically active material and / or ion-conducting material is wet-coated. 38. Material composites obtainable by a process according to at least one of claims 16 to 37. 39. Use of composite materials according to at least one of the Claims 1 to 15 and 38 in electrochemical cells, in particular in Fuel cells and electrolysers. 40. Use of composite materials according to at least one of the Claims 1 to 15 and 38 in electrolytic capacitors.