DE2614728A1 - COMPONENT FOR AN ELECTROCHEMICAL BATTERY - Google Patents

Description

BROWN, BOVERi & C! E ■ AKTIENGESELLSCHAFT 26 1 & 72

MANNHEIM "*" ~

Mp.- Kr. 524/76 Mannheim, March 10, 1976

ZFE / P1- ¥ g / Bt

Component for an electrochemical battery.

The invention relates to a component for an electrochemical battery, the cells of which have flat electrodes, each of which separated by an ion-conducting solid electrolyte and connected electrically in series.

Electrochemical batteries of this type are used for direct conversion the chemical energy released during the oxidation of a fuel gas into electrical energy "at high temperatures or for the electrolysis of water vapor. The components of a Such known batteries are tubular and have the electrodes on their outer surfaces. The production this component is complex and there is only one component contains a single cell, a large number of components must be inserted into the construction of high-performance batteries Sealed.— tjnd connecting means are strung together. These In addition to the electrical series connection of the electrodes, sealants and binders also provide sealing on the gas side. The disadvantage here is that the sealing and connecting means are not completely gas-tight and have little electrical properties Have conductivity, with the consequence of gas losses and high internal resistance of the battery.

703842/0133

P2i4fI? 2-3 £ 3G- "KEi

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524/76

ν, "* ~ 26HY28

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The invention is therefore based on the object of a component to specify for an electrochemical battery of the type mentioned, with a simple and inexpensive structure with as possible few other elements allow the easy assembly of electrochemical batteries of high power density, which can cope with the requirements that usually arise.

The solution to this problem is characterized in a component of the type mentioned by a gas-permeable, electrically non-conductive carrier body with at least one boundary surface which runs at a distance from one another, has open channels at the ends, on which the electrolytes and electrodes are arranged in the form of thin layers, with electrodes of opposite polarity of adjacent grooves and the free electrodes of the first and last troughs with electrical conductors, which delimit the troughs along their length Bridge bridges, are connected to one another or to electrical connections.

Since the electrodes and electrolysis are carried by the carrier body, it is sufficient to apply them in thin layers, preferably with a thickness between 10 and 100 μm, which results in a considerable saving in electrolyte material. Since the grooves and the webs of the carrier body are freely accessible, the electrolyte or electrode layers can be easily applied using the known thin-film processes. The same applies to the electrical conductors which connect electrodes of opposite poles of adjacent channels to one another or to electrical connections. Since the channels are preferably arranged next to each other with a very small distance,

709842/0133

ZFF./P 4 F 1 (675 5OOO / KE)

524/76 - * -

the carrier body is well used, and it can be used with the Assemble component batteries with high power density. The additional effort for the carrier body is negligible compared to the savings that are achieved in the construction of the component according to the invention.

As solid electrolytes in the context of the invention, should also be from a matrix absorbed electrolytes be understood.

For a particularly simple and clear structure of a battery, a preferred further development of the component is characterized in that the grooves, which are approximately semicircular in cross-section and are identical to one another, have their straight longitudinal axes parallel and with the same mutual spacing; run and in the case of a rectangular support body are also arranged parallel to a side surface of the support body. The thickness of the carrier body is in this case j is selected only in view of a sufficient mechanical \ strength.

In an advantageous manner, the webs which the grooves are on the longitudinal side limit, rounded at their longitudinal edges in such a way that the boundary surface has a wave-shaped profile.

Around the electrode carried directly by the channel, which is preferably the oxygen or air electrode to be better supplied with the associated reactants, has the opposite surface opposite the boundary surface to the Ends of open furrows that extend in the carrier body up to the vicinity of the grooves. As a result, the feed of the reac-: are secured even when several components are stacked on top of each other to form a battery and the weight of the component is reduced.

j - 4 -

709842/0133

ZrB ^- P 4 F 1 (6755Q00 / KE)

524/76

.j / "" 26H728

It is recommended that the straight furrows are symmetrical are arranged to a vertical plane bisecting the distance between two channels, parallel to the Grooves run and extend up to the vicinity of the boundary surface

A particularly preferred development now consists in ι that the mating surface has a wave profile, the wave troughs of which form the furrows.

In order to make the series connection of the electrodes and the current consumption easy, it has proven itself when the electrical Heads are arranged on the webs.

The electrical contacting of the electrodes is special here safe, if on each of the thin ladders there is a lateral extension of the electrical components running transversely to the channels: Troden is guided up to about half the width of the conductor and hits the opposing electrode of the neighboring cell. The thickness of the conductors here preferably corresponds approximately to the thickness of the electrodes.

Another connection of the electrodes with little effort is achieved if the lateral ends of the conductors are connected to each other one electrode of adjacent grooves are butt-connected. In this case, the conductor preferably has a thickness such that which allows easy connection of the electrodes.

If the component is used to build a battery for the oxidation of a hydrogen and / or at least one gaseous, Fuel gas containing hydrogen-containing compound is provided, so it is advantageous if the conductors are made of nickel or consist of a nickel alloy and have the form of a foil or a vapor-deposited layer. Because the inevitable

709842 / 0Ϊ-33-

(b / f.büOO / KEi

¹ conductors that come into contact with the fuel gas take water- J

t substance or a hydrogen compound from the fuel gas, j

ι -

j which protect them from attack by oxygen or air at high temperatures, so that good electrical conductivity can be exploited by nickel or nickel alloys.

¹ The least problems related to the ladder then arise, j

if this comes from one against reducing and oxidizing atmos- pheric;

sphere-resistant material, which is also electrically good;

j is conductive. I.

The simplest overall structure of the component is available when the electrodes and the conductors are made from one anti-oxidant i and reducing atmosphere resistant material and • opposing polarity electrodes of adjacent channels! together with the

The ladders attached to the webs are formed from one piece: «Since this material is used as fuel and oxygen

bsw. Air electrode is usable, it does not matter which one Elelrtroden the fuel or oxygen or air supplied; will. !

- i

In order to achieve a good supply of the electrical current, it has proven to be useful if the electrical connection Je- _; J because of one on the thickness of the connected electrode Ί ! or the connected conductor coordinated, outwardly ι thin strips of metal or oxidic electrode

! I.

! material, the length of which is at least the length of the gutters

1 ί

I corresponds and its contacting with the respective associated! j Electrode corresponding to the other electrical connections!

i the battery is designed. I.

i i

! j

709842/0133

ZFB.'P 4 F 1 (SiSfCCGSiCe)

5? 4/76

-4 - I.

To further simplify the electrical connection, tried and tested
it is when the one arranged on the first and last Ste £
Head is led to the outside and extends at least j over part of the side surface of the base body | and forms the electrical connection. |

Further advantages of the invention emerge from the following description Practice of exemplary embodiments in connection with the drawing! which show the following schematically:

1 shows a component according to the invention with a carrier body '' in the form of a flat cuboid in a perspective front view with grooves pointing upwards, j

Fig. 2 the object of Figure 1 with on the opposite surface! arranged furrows as well as with another type of connection the electrodes and connections and downward j-pointing grooves,

3 shows the area III of FIG. 2 with an embodiment variant of the electrical connection on a larger scale
Hate wand,

FIG. 4 shows the object of FIG. 2 on the opposite surface

arranged furrows, which are co-formed by a corrugation are, as well as with a variant of the electrodes,

FIG. 5 shows a section corresponding to area V of FIG. 4 through a component with rounded webs
and another connection of the electrodes and

6 shows a compilation with components according to FIG
Battery.

709842/0133

ZFE / P 4 F 1 (675 5000 / KE)

524/76

~ ^γ - 26,728

The component shown in Figure 1 has a flat cuboid support body 1 made of a gas-permeable and electrically non-conductive material, such as magnesium oxide or zirconium-calcium oxide. The upper large perimeter area 2 has three grooves 3, 4, 5, which one narrow end face 6 of the support body with the opposite end face associate. The grooves are straight, run parallel to the side surface 7 and point one below the other in each case the same distance. The cross-sections of the channels 3 to 5 are identical to one another and are semicircular and its radius is chosen so that there is sufficient space between the bottom of the channel and the counter surface 9 of the support body Material thickness ensuring the strength of the component remains. The bridges remaining between the gutters or the webs 11, which delimit the first channel 3 and the last channel 5 to the outside, are only with their thickness Consideration of the strength of the support body and the safe electrical connection of the electrodes laid out, i.e. the carrier body is provided with as many channels as possible. The side length of a carrier body is each According to the radius of the gutters, about 5 cm to 100 cm. On the walls of the channels 3 to 5, which preferably have a radius between 1 and 25 mm, is initially in each case an electrode 12, preferably designed as an oxygen or air electrode, is applied, each of which in turn, with the thin electrolyte 13 is made of an oxygen ion conductive material such as doped zirconium oxide, which each of the opposite polarity electrode 14 carries. The electrodes are separated from the solid electrolyte.

On the surfaces of the webs 10, 11 each is an electrical Conductor 15, 16 applied, which each over [ j extends the entire surface.

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: 709842/0133 ι

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¥ ie further shown in Figure 1, opposing polarity electrodes of adjacent grooves with their lateral ends 17 » 18 out to half the width of the electrical conductor 15, where they meet. Since these ends 17 »18 immediately run on conductor 15 and extend the entire axial length of the grooves is an overlapped electrical one Connection of the electrodes of opposite polarity established

According to FIG. 1, the electrical connections 19 used for current discharge consist of thin metal strips that extend over extend the entire axial length of the grooves. These strips are used for connection to the respective electrodes on the conductors 16 up to about half the width of the webs 11 where they meet the extended lateral ends of the electrodes, i.e. the connection between the terminals 19 and the elel "+ clearing is here just as trained as the connection of electrodes of opposite polarity in adjacent channels.

In order to avoid short circuits, there is in each case between the left end of the electrodes 12 and the electrical conductor 15 »16 a safety distance 20 maintained from the electrolyte j

13 is completed. ;

In the exemplary embodiment according to FIG. 1, the electrical conductors 15, 16 consist of gas-tight sintered lanthanum-manganese oxide or lanthanum-chromium oxide, which are doped with strontium and have an addition of bismuth oxide. Is the electrical \ conductor not gastight executable, the top must each j surface of the webs 10, 11 may be gas-tight, for example ^by! Sintering or glazing in order to avoid that the reactants assigned to each electrode come into contact with the counter electrode. This is particularly important for nickel electrodes, which are very sensitive to gases containing oxygen at high temperatures.

709842 / 013-39-

Zf t / P 4 F 1 (b75 5000 / KEi

524/76

~ ' 2B14728

If the conductors are made of nickel or a nickel alloy and come into contact with oxygen or air, they must Heads for a hydrogen and / or at least one gaseous, hydrogen-containing compound atmosphere containing it. The hydrogen diffuses into the nickel baw * nickel alloy and protects so from corrosion at high temperatures. An additional special supply of such gases for reasons of corrosion protection is not required if it is guaranteed that the fuel gases supplied contain hydrogen and that the Touch kick parts.

The carrier body 1 is produced in the pressing process and the electrodes and electrolytes are made with the aid of thin-film processes, such as plasma spray processes or CYD processes (chemical vapor deposition processes), one after the other Walls of the gutters applied. The conductors 15, 16 are also made in the same way. the surfaces of the webs 10, 11 have been arranged, if these are made of electrode material exist. The connections 19 are made, for example, by welding processes or sintering process attached to the conductors 16.

The embodiment variant of a component shown in FIG. 2 with grooves pointing downwards has in principle the the same structure as the component according to FIG. However, there are differences here with regard to the electrical Series connection of electrodes with opposite polarity and the formation of the carrier body 1. The carrier body also has here Grooves 37 "of V-shaped cross-section, which the mating surface 9 and penetrate into the carrier body. The longitudinal axes of these furrows run parallel to the grooves and connect the shell face 6 with the opposite

- 10 709842/0133

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lying face. The tips of these furrows each end at such a distance in front of the conductor 35 »dai> a sufficient mechanical cohesion of the carrier body is maintained. The maximum allowable vertical widening of the cross-section of the furrows is also determined by the strength of the remaining carrier material. The cross section the furrow is symmetrical about a vertical plane 21 passing through the top of the furrow which defines the distance the grooves halved and indicated as a dash-dotted line. The purpose of these grooves is for the only having to guide the electrodes 12 specific reactants over a short path through the porous component. For the same The side surfaces 7 are also beveled.

The electrical conductors 35, 36, which roughly correspond in their design to the conductors according to the exemplary embodiment according to FIG. 1, are butt-connected to electrodes 12, 14 of opposite polarity. The electrodes 12 and 14 are the first and last channel 3 or 5 sen with the Anschlüs- 'are connected 39 to the same type, which are formed corresponding to the terminals in accordance with \ the embodiment according to FIG. 1 The thickness of the conductors is designed so that an easy connection with the electrodes or connections is possible.

FIG. 3 shows a detail according to III of FIG. 2 on a larger scale and in an embodiment variant of connection 39 is shown. In order to form the connection, the conductor 36 is guided and extended to the outside in each case extends with its end region 38 over part of the side surface 7 and thus forms the electrical connection. These The embodiment of the electrical connection can of course also be used in the other exemplary embodiments shown here.

- 11 -709842 / 01 * 5

ZFE / P 4 F 1 (675 500O / KE)

524/76

The variant embodiment of FIG 4 according corresponds in its basic design of the component 2, a sub j difference is that the upper edges of the grooves are rounded off j I, so that the counter surface 9 which in Figure 4 DAR I \ Asked wave profile contains and each a wave trough 24! a groove 37 forms. The electrodes 42 and 44 contain ^! here with strontium doped lanthanum manganese oxide with a

j I

ι addition of bismuth oxide. Since this material is against oxidizing! i and the reducing atmosphere is resistant, the electrodes produced therewith can be used either as anode or cathode, it is therefore irrelevant whether the fuel gas is fed to the electrode 42 or 44. The addition of bismuth j I oxide (Bi ₂ O) facilitated the processing of the material and \ j increases its adhesiveness. When using this material jj there is also the advantage that with it too! j the electrical conductors 45, 46 can be produced, j which bridge the webs 40. As can be seen from FIG. 4, electrodes of opposite polarity of adjacent cells are produced together with the conductors 45 from one piece and from the same material. The electrodes 42 and 44 of the first and last troughs 3 and 5, respectively, are also produced in one piece together with the conductors 46 and the connections 49 are formed in accordance with FIG. In order to avoid losses of reactants, the conductors 45, 46 are also made gas-tight here or the carrier body is sintered gas-tight in the area of these conductors (webs).

For the production of the material for the electrodes * will be Lanthanum oxide, manganese oxide or chromium oxide and strontium oxide or strontium carbonate ground and in the proportions

* or head

• - 12 -

709842/0133

ZFE / P 4 F 1 (675 5000 / KE)

524/76

2814728

which are specified in claims 18 and 19, respectively, mixed and about 10% bismuth oxide (Bi ₂ O ₅ ), based on the weight of the mixture, added and mixed again. After about 5 to 10 hours of heating in air to about 150O ⁰ C, the mixture is cooled, whereby it solidifies. The proportion of Bi ₃ O ₅ has dropped to about 2% as a result of the heating. After grinding and sieving according to grain size, the material for the electrodes is ready for use. This material is applied to the electrolyte to form the electrodes in a known manner, for example by plasma spraying or sintering. Here, the proportion of Bi ₂ O falls further to values between 0.1 and 136.

FIG. 5 shows a section of a component which corresponds to the bordered area Ύ of FIG. 4, but shows a different design of the web 50 and the electrode connection. The edges of the web 50 are rounded here, so that the boundary surface 2 is given a wave profile. Such a design can also advantageously be transferred to all other exemplary embodiments.

The electrode 52, which is the oxygen or air electrode, extends with a lateral extension in each case over the web 50 and forms the conductor 55. The conductor is made gas-tight, e.g. by applying the Electrode material in the plasma spray process and impregnation; with an aqueous nitrate solution of the electrode material concerned. The counter electrode is also extended laterally and extends in the area of the web 50 over the electrode 52. Since the electrode 52 in the area of the web 50 is gas-tight is, the electrode 54 is protected against corrosion by the oxygen or air.

- 13 -

709842/0133

I 167SS000 / KE)

524/76

6 shows an electrochemical battery assembled with components according to FIG. For this purpose, two components with their grooves are attached to one another in such a way that circular channels 22 are formed. It is not necessary here to insert sealing means between the electrical conductors 35 of the upper and lower part, since there may be a gap between the two components on both sides which each lead the same reactants opens into the channels 22. The only essential thing is a gas-tight connection of the two components in the area of the conductors 36 in order to prevent the reactants from escaping to the outer space 23 .

When assembling the individual components, care must also be taken that only conductors with the same name carry the same voltage come to lie on top of one another, so that electrodes of the same name of a channel 22 are connected in parallel and one cell j

of the battery. !

In Figure 6, the components are overlooked because of low i Distance shown, but for use they must be attached to one another in the aforementioned manner.

- 14 -

709842/0133

ZFE / P 4 F 1 (675SO00 / KE)

Claims (1)

524/76 26U728 Claims 1 Component for an electrochemical battery, the cells of which have flat electrodes, which are each separated by an ion-conducting solid electrolyte and electrically connected in series, characterized by a gas-permeable, electrically non-conducting carrier body (1) with at least one boundary surface (2) which is spaced apart each "extending, on the ends \ offenene grooves (3, 4, 5), on which the electrolytes (13) and electrodes (12, 14; 42, 44; 52, 54) are arranged in the form of thin layers I, where; opposite polarity electrodes of adjacent grooves and the free j electrodes of the first and last grooves (3, 5) with electrical conductors (15, 16; 35, 36: 45, 46; 55), which webs (10, 11 ; 30, 31; 40; 50), are connected to one another or to electrical connections (19} 39J 49). 2. Component according to claim 1, characterized in that the grooves in a top surface of approximately the shape of a rectangular plate having support body formed Component according to claim 1 or 2, characterized in that the cross-section is approximately semicircular and one below the other same grooves (3, 4 »5) with their straight longitudinal axes parallel and with the same mutual Distance run and in the case of a rectangular Support body are additionally arranged parallel to a side surface (7) of the support body. - 15 - ORfQlNAL INSPECTED 700842/0133 524/76 4 «component according to claim 3, characterized in that the Bridges (5ö) i which delimit the grooves along the length their Läsgskanten are rounded so that the boundary surface (2) has an undulating profile. (Fig. 5) 5. Component according to one of claims 1 to 4, characterized in that the mating surface (9) opposite the boundary surface (2) has open grooves (37) at the ends »which extend in the support body up to the vicinity of the grooves (3 to 5 ) extend »(Fig _s 2} 6. Component according to claim 3 and 5 » characterized in that the straight grooves (37) are arranged symmetrically to a vertical plane bisecting the distance between two grooves ₉ run parallel to the grooves and extend into the vicinity of the boundary surface (2) . (Fig. 2) 7. Component according to claim 6 _S, characterized in that the counter surface has a wave profile, the wave troughs (24) form the grooves (37) «(Fig. 4) S. component according to one of claims 1 to 7 _f, characterized in that the oxygen or air electrodes are placed directly on the channels. (3 to 5) are arranged. 9. Component according to one of claims 1 to 8, characterized in that that the ladder (15, 16? 35, 36; 45, 46; 55) are arranged on the webs (10, 11; 30, 31; 40 »50). 10. Component according to claim 9, characterized in that the conductors are gas-tight. - 16 - 709842/01 ti FM ί 1 (67tiSC-5j-i> iLi 524/76 11. Component according to claim 9, characterized in that the The conductors are gas-permeable and the webs in the area of the conductors are gas-tight, e.g. by sintering or Glazing. 12. Component according to one of claims 9 to 11, characterized in that that on the thin conductors (15) each a transverse to the grooves (3 to 5) extending, lateral ■ Extension (17 »18) of the electrodes about halfway Width of the conductor (15) is guided and abuts the opposing electrode of the adjacent channel. (Fig. 1) 13. Component according to one of Claims 9 to 11, characterized in that that the appropriate ends of the conductors (35) each to an electrode of adjacent grooves (3 to 5) are butt connected. (Fig. 2) 14 »Component according to claim 12 or 13, for building a battery ^ for the oxidation of a hydrogen and / or at least one gaseous, hydrogen-containing compound Fuel gas, characterized in that the conductors consist of nickel or a nickel alloy and the Have the form of a film or a vapor-deposited layer. $ 1. Component according to Claim 10, with a nickel-containing fuel electrode, characterized in that the conductors (55 are each supported by a lateral extension of the oxygen or Air electrodes (5 2) are formed by lateral extensions of the fuel electrodes (54) the neighboring cells are covered. (Fig. 5) - 17 - 709842/0133 ZFE / P 4 F 1 (675.5000 / KE) . *. 26H728 16. Component according to one of claims 9 to 13, characterized in that that the conductors are made of a material that is resistant to reducing and oxidizing atmospheres. 17. Component according to one of claims 1 to 8, characterized in that that the electrodes (42, 44) and the conductors (45, 46) from an anti-oxidizing and reducing Atmosphere-resistant material and opposing electrodes of adjacent channels (3 to 5) together with the conductors (45) attached to the webs are formed in one piece. (Fig. 4) 18. Component according to claim 16 or 17, characterized in that a 0.1 to 1 $ Bi ₂ O _5- containing material of the formula for the electrodes or conductors La "Me? Me ¹¹ O ,, is used, Me strontium and Me manganese, nickel! or chromium and χ has the values 0.74 to 0.92, y has the values 0.08 to 0.26. 19. Component according to claim 18, characterized in that χ has the values 0.82 to 0.86 and y has the values 0.14 to 0.18. 20. Component according to one of claims 12 to 15, characterized in that> characterized in that the electrical connection (19, 39) each consists of one on the thickness of the connected Electrode (12, 14) or the connected conductor (36) matched thin strips of metal or oxidic electrode material that lead outwards consists, the length of which corresponds approximately to the length of the grooves (3, 5) and its contact with the respectively associated electrodes is formed in accordance with the other electrical connections of the component. (Fig. 1, 2) 709842/0133 - 18 - ZFE / P 4 F 1 (675.5000 / KE) 524/76 . * 26U728 21. Component according to claim 20, characterized in that the conductor arranged on the first and last webs (36, 46) is each led to the outside and extends at least over part of the side surface (7) of the base body extends and forms the electrical connection. (Fig. 3, 4) 22. Composed of components according to one of claims 1 to 21 Solid electrolyte battery, characterized in that two components with overlapping grooves placed on top of one another and connected to one another in a gas-tight manner at least in the region of the first and last webs (31) are. (Fig. 6) ! 709842/0133 ZFE / P 4 F 1 (675.5000 / KEj