DE4033708A1 - Conductive part for interconnection of high temp. fuel cells - comprises sheet metal folded to form sepg. wall and contact area for fuel electrode of one cell and oxygen-electrode of another cell - Google Patents

Abstract

The part (4) has to conduct current between 2 adjacent solid electrolyte, high temp., fuel-cells which have a flat shape and are arranged in a stack. The fuel cells consist of a solid electrolyte membrane (1), an oxygen electrode (2) and a fuel-electrode (3). The part (4) connects dissimilar electrodes of 2 adjacent cells, forming a conductive hermetic, separating wall (5) between flows of the fuel and of the oxygen medium. The feature is that the part (4) consists of a single sheet of metal which has been folded more than once in such a way that the central part forms the separating wall (5) and the other parts are springy current collectors (6,7) with multiple contacts on the electrodes due to the presence of folds and raised dents. The collectors pref. extend over the entire electrode surface. They may be of any form, i.e. triangular, square, rectangular, interdigitated and consist of 2 parts which butt onto each other above each electrode and each cover half the electrode area. USE/ADVANTAGE - The part (4) can be formed in a simple operation, gives a good electrical contact at a temp. of up to 1000 deg. C and has a high conductivity. It can be used both in reducing and in oxidising ambients. The part has a low cost, can be made reproducibly and can be easily exchanged.

Description

High temperature fuel cells for converting chemical Energy in electrical energy. The electrochemical Energy conversion and the devices required for this win thanks to their good efficiency compared to others Types of conversions in importance.

The invention relates to the further development of using high temperature electrochemical cells of ceramic solid electrolytes as ion conductors, whereby the cells are largely independent of the fuel used should be and provide a space-saving arrangement should.

In the narrower sense, the invention relates to a component for Power transmission between neighboring flat, flat, stacked high-temperature fuel cells with solid electrolyte based on stabilized Zirconium oxide, with the oxygen electrode in each case Fuel cell with the fuel electrode of the next one Fuel cell electrically connected and the between  the gap between the electrodes through a gas-tight, electrically conductive separating wall in two, the different gaseous media fuel (CH₄) and Oxygen carrier (O₂) leading rooms is divided.

State of the art

High-temperature fuel cells with ceramic solid electrolytes are known from numerous publications. The actual elements for such cells can have a wide variety of shapes and dimensions. In order to keep the ohmic voltage losses small, everywhere tried the thickness of the electrolyte layer as possible to keep low. Shape and dimension of the elements are also based on the requirement of the possibility of electrical series connection of a variety of cells to to come to the necessary terminal voltage and the currents to keep comparatively low.

In the case of a stacked arrangement of a plurality of plate-shaped flat fuel cells similar to the filter press In principle, the current must be perpendicular to the plate level from the oxygen electrode of one cell to the fuel electrode the next succeeding cell. As essential components for this function are electrical Links to the electrodes (current collectors) and Separation plates (bipolar plates) required.

The previously known components are satisfactory in many respects the materials used, the construction and Manufacturing as well as the long-term behavior of the modern requirements Not.  

The known basic elements used for fuel cells are usually characterized by a comparative complicated geometry that required the construction of compact, space-saving systems difficult. In particular, one is missing usable for an optimal series connection of the single cells Configuration that can be done with simple manufacturing tools can be realized.

There is therefore a great need for further development, Simplification and rationalization of construction and the production of current-carrying basic components and their optimal design and production-oriented design.

The following publications become state of the art called:

• - O. Antonsen, W. Baukal and W. Fischer, "High temperature Fuel battery with ceramic electrolyte ", Brown Boveri Announcements January / February 1966, pages 21-30,
• - US-A-46 92 274
• - US-A-43 95 468
• - W. J. Dollard and W. G. Parker, "An overview of the Westinghouse Electric Corporation solid oxide fuel cell program ", Extended Abstracts, Fuel Cell Technology and Applications, International Seminar, Den Haag, Netherlands, October 26-29, 1987,
• - F. J. Rohr, High-Temperature Fuel Cells, Solid Electrolytes, 1978 by Academic Press, Inc. page 431 ff.
• - D.C. Fee et al., Monolithic Fuel Cell Development, Argonne National Laboratory, Paper presented at the 1986 Fuel Cell Seminar, Oct. 26-29, 1986 Tucson, AZ, U.S. Department of Energy.

Presentation of the invention

The invention has for its object a component for power transmission between neighboring levels, stacked high-temperature fuel cells indicate which has good electrical contact to the Electrodes of the fuel cells at temperatures up to Guaranteed 1000 ° C and in turn a high metallic has electrical conductivity and both in reducing, neutral as in an oxidizing atmosphere can be used and also a sufficient Has long-term stability. The component should be inexpensive, reproducibly and interchangeably manufactured can be.

This object is achieved in that the aforementioned Component from a single, multiple folded consists of a monolithic sheet metal part which is shaped in such a way that a middle part separates the wall and the two outer parts perpendicular to the plate plane of the fuel cell form fully elastic current collectors, which a variety of the electrically conductive points of contact to the neighboring electrodes in the form of waves, folds or nubs.

Way of carrying out the invention

The invention is illustrated by the following figures described exemplary embodiments.

It shows

Fig. 1 is a schematic perspective view of the basic construction of adjacent fuel cells and an intermediate device for power transmission,

Fig. 2 is a plan view of a sheet member according to an unwound component prior to shaping,

Fig. 3 is a perspective view of a device for Stomübertragung with a rectangular ground plan,

Fig. 4 is a plan view of a plate member having rectangular cloth prior to shaping,

Fig. 5 is a plan view of abutting sheet metal elements (rectangular cloth) with little waste in the sheet metal section,

Fig. 6 is a perspective view of a device for power transmission with the current collectors with a triangular ground plan,

Fig. 7 is a plan view of a plate member with triangular flaps prior to shaping,

Fig. 8 is a plan view of abutting sheet metal elements (triangular lobes) with little waste in the sheet metal section,

Fig. 9 is a perspective view of a device for power transmission with the current collectors with a comb-like interlocking rectangular resilient lamellae,

Fig. 10 is a plan view of a plate member having rectangular lamellae before molding,

Fig. 11 is a plan view of abutting sheet metal elements (rectangular fins) with little waste in the sheet metal section,

Fig. 12 is a perspective view of a device for power transmission with the current collectors with a comb-like interlocking triangular resilient lamellae,

Fig. 13 is a plan view of a plate member with triangular lamellae before molding,

Fig. 14 is an elevation / section of a component for power transmission with current collectors as corrugated, butt-jointed rectangular resilient slats.

Fig. 1 relates to a schematic perspective view of the basic structure of two adjacent fuel cells and an intermediate component for power transmission. The actual fuel cell consists of the ceramic solid electrolyte 1 made of doped, stabilized ZrO₂, the porous (positive) oxygen electrode 2 made of doped La / Mn perovskite and the also porous (negative) fuel electrode 3 made of Ni / ZrO₂ cermet. In between is a monolithic component 4 for power transmission between adjacent fuel cells. 5 is the part of the monolithic component which acts as a separating wall (separating plate). 6 represents the part of the monolithic component which acts as a current collector on the fuel side. FIG. 7 is the part of the monolithic component which acts as a current collector on the oxygen side. The fold zone of the element is indicated by 9 .

The symbol CH₄ generally stands for that of the gaseous Flooded with fuel, the symbol O₂ for the gaseous Oxygen carrier (air) flooded space of the fuel cell. In the present case, the currents are the gaseous media directed in parallel: direct current principle for CH₄ and O₂!

In Fig. 2, a plan view of a sheet metal element corresponding to a developed component is basically shown before shaping. 8 is the developed rectangular component: plan of the corresponding sheet metal element. 5 is the middle part of the element which acts as a separating plate and to which the parts which act as current collectors after shaping are connected on both sides. The fold zones of the element are indicated by 9 in the form of dashed lines. 10 are the electrically conductive contact points (contact points) located at the top of the development of the elevations of the element on the oxygen side (not shown here). 11 are the corresponding contact points (contact points) of the elevations on the fuel side.

Fig. 3 relates to a perspective view of a component for power transmission with current collectors with a rectangular plan. 4 is the monolithic component consisting of a single sheet metal body. The part 6 , which acts as a current collector on the fuel side, consists of two rectangular halves meeting bluntly in the middle of the projection of the fuel cell. The same applies to part 7 , which acts as a current collector on the oxygen side, with the difference that the center line of the butt-meeting halves is perpendicular to that of part 6 . The fold zones 9 of the element thus form a right angle to one another. As a result, two channels for the flowing gaseous media are created between the part acting as the separating plate 5 and the part 6 on the one hand and the part 7 on the other hand, with their openings perpendicular to one another: cross-flow principle for CH₄ and O₂!

In FIG. 4 a plan view is shown of a plate member having a rectangular cloth before forming. The reference numerals correspond exactly to those of FIG. 2. Instead of only 2, however, there are 4 tabs for the part acting as current collectors. Accordingly, this results in a total of 4 folding zones 9 of the element. In order to take into account the material expenditure required for the folding with the greatest possible radius of curvature and for the profiling (waves, elevations, etc.) of the current collectors - not shown in the figure - the area of the current collector portion of the sheet metal element is greater than twice the value of the partition plate portion (projection corresponds to the fuel cell area).

Fig. 5 shows a plan of abutting sheet metal elements with rectangular lobes. From this it can be seen that with skilful stringing together of the unwound components 8 , only a small drop in sheet metal cutting can be expected.

Fig. 6 shows a perspective view of a component for power transmission with current collectors with a triangular plan again. 4 is the monolithic component consisting of a single sheet metal body. Part 6 , which acts as a current collector on the fuel side, consists of two triangular halves that meet bluntly in the diagonal of the projection of the fuel cell.

In the same way, the part 7 acting on the oxygen side as a current collector is formed. In the present case, the butt joints of the butt-meeting halves lie on parallel surface diagonals. Of course, they can also lie on intersecting diagonals. For the most waste-free sheet metal recycling, however, the first variant is better (see Fig. 7!). Otherwise, the reference numerals correspond exactly to those of Fig. 3. This also applies to the basic structure of the element: cross-flow principle for CH₄ and O₂!

In Fig. 7 is a plan view of a sheet metal element with triangular lobes before shaping. The reference numerals correspond exactly to those in FIG. 4. There are 4 triangular tabs for the part which acts as current collectors. The 4 folding zones 9 of the element enclose a square in the present case. Because of the material expenditure already described under FIG. 4, the tabs are longer than the dimensions of the partition plate portion.

Fig. 8 shows a plan of abutting sheet metal elements with triangular lobes. The optimal lining up of the unwound components 8 leads to little waste in sheet metal cutting.

Fig. 9 shows a perspective view of a component for power transmission with current collectors with comb-like interlocking rectangular slats. 4 again shows the monolithic component consisting of a single sheet metal body. The part 6 , acting as a current collector on the fuel side, consists of a large number of resilient rectangular lamellae 12 which engage from two opposite sides while maintaining lateral play. As a rule, these lamellae are designed as wavy tongues (not shown in FIG. 9). The part 7 acting on the oxygen side as a current collector is designed in the same way in the form of resilient rectangular lamellae 13 . Furthermore, the reference numerals correspond exactly to those of Fig. 3. Cross-flow principle for CH₄ and O₂!

In Fig. 10 a plan view is shown of a plate member having rectangular lamellae before molding. The reference numerals generally correspond to those of FIG. 4 and FIG. 9, for acting as a current collector part are comb-like rectangular resilient fins 12 on the fuel side and 13 just such available for the oxygen side. The lamellae on one side correspond to recesses on the opposite side, the latter being kept wider, so that a certain lateral play is ensured when bending together. For the cost of materials is true for FIG. 4 and FIG. 7 is said.

Fig. 11 shows a plan of abutting sheet metal elements with rectangular lamellas. The stringing together of the unwound components 8 can be designed so that a minimal waste arises through comb-like interlocking during sheet metal cutting.

Fig. 12 shows a perspective view of a component for power transmission with current collectors with comb-like interlocking triangular resilient slats. 4 is the monolithic component consisting of a single sheet metal body. The part 6 , which acts as a current collector on the fuel side, consists of a plurality of resilient triangular, tapering lamellae 12 which engage with one another from two opposite sides while maintaining a certain lateral play. In the present case, the lamellae are designed as wavy tongues (not shown in FIG. 12). The part 7 acting as a current collector is designed in the same way in the form of resilient triangular lamellae 13 . The remaining reference numerals correspond to those of Fig. 3. For the flows of the gaseous media CH₄ and O₂, the cross-flow principle applies!

In Fig. 13 is a plan view of a sheet metal element with triangular lamellae before shaping. The reference numerals correspond to those of FIG. 9. For the part acting as current collectors, comb-like, triangularly tapering, resilient slats 12 for the fuel side and corresponding slats 13 for the oxygen side are present. The lamellae on one side correspond to triangular recesses on the opposite side, with a certain amount of lateral play after bending. What was said earlier applies to the detailed design of these tongues (shafts, nubs, warts, elevations) and to the material expenditure.

Fig. 14 relates to an elevation / section of a component for power transmission with current collectors as corrugated, butt-jointed rectangular resilient slats. 5 the part of the monolithic component acting as a separating wall (separating plate) is seen from the edge. 6 shows that part of the monolithic component which acts as a current collector on the fuel side in the form of sinusoidally corrugated fins. The apexes of the waves are supported on the one hand on the fuel electrode and on the other hand on the separating plate part 5 . In Fig. 14, a symmetrical arrangement is shown. The lamellae can also be arranged asymmetrically and the waves of lamellae lying next to one another can be offset from one another. The vectors CH₄ indicate the direction of flow of the fuel perpendicular to the plane of the drawing, into it. 7 shows the part of the monolithic component acting as a current collector on the oxygen side in the form of sinusoidally corrugated lamellae (dashed vertical lines). The waveform is rotated in profile by 90 ° (side elevation) in the form of a dash-dotted sine curve. The vector O₂ for the oxygen carrier is perpendicular to the vector CH₄: cross-flow principle! 10 and 11 are the electrically conductive points of contact (contact points) to the electrodes.

Embodiment See Fig. 1 and 2!

A monolithic component 4 for power transmission was made from an oxide dispersion-hardened noble metal. The projection of the electrode area was a square with a side length of 100 mm. An aluminum alloy with Al₂O₃ as the dispersoid was chosen as the material. The composition was as follows:

Al₂O₃ = 1% by weight
Au = rest

First, an Au / Al alloy was melted, cast into an ingot and processed into a sheet with a thickness of 0.4 mm by hot and cold rolling. A rectangle (sheet metal element 8 ) 100 mm wide and 375 mm long was punched out of the sheet. The parts 6 and 7 (end flaps) provided as current collectors were pressed by pressing them into flat sinusoidal, parallel waves of 8 mm wavelength and 1 mm amplitude and provided with elevations on the wave apexes on the side facing the electrode. The latter were designed in the form of knobs 0.4 mm high and 1.5 mm in diameter with a lateral spacing of 6 mm. In this way, an orthogonal pattern of contact points 10, 11 was created both on the oxygen side and on the fuel side. In the diagonal in the middle between 4 neighboring knobs, holes of 5 mm diameter were punched into the corresponding wave crests (wave troughs) for the passage of the gaseous media. The sheet metal element 8 was then folded on the oxygen side by a mandrel with a radius of curvature of 3 mm by 180 ° and on the fuel side by a mandrel with a radius of curvature of 1 mm in the opposite direction, likewise by 180 °. The entire component thus had a total height including protruding knobs of 12 mm. An average clear height of 2 mm was available for the CHstrom fuel flow, and 6 mm for the oxygen carrier flow (air) O₂. The component 4 was then annealed under an O₂ partial pressure of 3 bar for 6 h at 850 ° C to form the Al₂O₃ dispersoid in a fine distribution.

Embodiment 2 See Fig. 1 and 2!

A monolithic component 4 was produced from an oxide dispersion-hardened Ni / Cr alloy with the trade name TD NiCr with the following composition:

Cr = 20% by weight
ThO₂ = 2% by weight
Ni = rest.

The procedure was analogous to Example 1. A commercially available sheet of 0.35 mm thickness was used for this purpose. The sheet metal element 8 stamped therefrom had the same surface dimensions as in Example 1. The arrangement of the shafts, knobs and holes was also the same. Now the part 6 of the sheet metal element 8 which later acts as a current collector on the fuel side, the part 5 which acts as a separating plate only on the fuel side and the part 7 which acts as a current collector on the oxygen side only on the oxygen electrode side with an intermediate layer consisting of Ni₃Si as Provide diffusion barrier. This intermediate layer was applied by sputtering to a thickness of 15 μm. A protective layer (electrical contact layer) of 40 μm thickness made of palladium was electrochemically deposited on this intermediate layer both on part 6 and on part 7 , but only on the sides lying on the electrodes. Then the sheet metal element 8 coated in this way was bent analogously to Example 1 along the folding zones 9 around corresponding mandrels and brought into the final shape. The component 4 shaped in this way was then finally subjected to an annealing treatment under an oxidizing atmosphere at a temperature of 950 ° C. for 10 h. A coherent protective layer of Cr₂O₃ was formed on the uncovered areas of the element and one made of SiO₂ on the areas covered with an intermediate layer of Ni₃Si. The areas coated with Pd remained bare. The Cr₂O₃ protects the underlying core material in operation against further oxidation, the SiO₂ likewise against carburization (carburization).

Embodiment 3 See Fig. 3 and 4!

A monolithic component 4 for power transmission was produced from an oxide dispersion hardened noble metal alloy. The projection of the electrode area was a square with a side length of 120 mm. An Au / Pd alloy with ThO₂ as the dispersoid was used as the material. The composition was chosen as follows:

ThO₂ = 2% by weight
Pd = 40% by weight
Au = rest

The alloy was chemically produced from the precious metal chlorides by precipitation and addition of the precipitation products to ThO₂ particles in suspension. The powder produced in this way, containing the ThO₂ as an ultrafine dispersoid, was further processed by powder metallurgical methods into a flat strand and into a sheet of 0.45 mm thickness. A sheet metal element 8 according to FIG. 4 was punched out of the sheet metal. The flaps adjoining the square area of 120 mm × 120 mm on the fuel side had a width of 70 mm, those on the oxygen side 80 mm. In each of the parts 6 and 7 provided as current collectors, a sinusoidal wave of 6 mm wavelength was pressed by pressing, which had an amplitude of 1.5 mm on the fuel side and 3 mm on the oxygen side. These single waves each formed a channel parallel to the direction of flow of the corresponding gaseous medium (CH₄ or O₂). In parts 6 and 7 , warts with a height of 0.3 mm and a center distance of 6 mm were pressed in according to an orthogonal grid. The convex sides of these warts each pointed in the direction of the corresponding electrode (electrically conductive contact points 10 and 11, respectively). Between these warts, holes of 4 mm diameter were punched on their diagonal connections for the gas to pass through. Then the sheet metal element 8 was bent around mandrels of 3 mm or 1.5 mm radius of curvature by 180 ° in each case. A clear height of 3 mm was available for the CHstrom fuel stream and 6 mm for the oxygen carrier stream O₂.

Embodiment 4 See Fig. 3 and 4!

The monolithic component 4 had exactly the same Area dimensions and was basically the same  Methods prepared as indicated in Example 3. An oxide dispersion-hardened precious metal was used as the material with the following composition:

ThO₂ = 1.8% by weight
Pd = rest

Similar to Example 1, the alloy was produced in a powder form by means of a precipitation reaction, compacted and hot and cold worked. The sheet metal element 8 had a thickness of 0.3 mm and was provided in its part 5, which acts as a dividing wall, with a large number of flat, 0.25 mm deep circular dents for the purpose of stiffening. Otherwise, the structure corresponded exactly to that of Example 3.

Embodiments 5 See Figs. 6 and 7!

A monolithic component 4 for power transmission was made from a dispersion-hardened noble metal. The projection of the electrode area was a square with a side length of 100 mm. A precious metal with the following composition was selected as the material:

TiC = 0.06% by weight (approx.0.15% by volume)
Pd = rest

Powder metallurgical processes were used to produce the alloy. Pd powder with a maximum particle size of 10 µm was ground with 0.06% by weight TiC powder with a maximum particle size of 0.8 µm for 30 hours under toluene in an attritor (high-speed ball mill) and alloyed mechanically. The powder, which was cold worked to saturation, was dried and filled into a soft iron can, evacuated and sealed gas-tight. The filled can was extruded at a temperature of 1150 ° C. with a reduction ratio of 30: 1 into a flat bar 50 mm wide and 6 mm thick. The workpiece was further processed into a sheet 0.35 mm thick by hot and cold rolling. A sheet metal element 8 according to FIG. 7 was punched out of the sheet metal. The triangular lobes adjoining the square area of 100 mm × 100 mm had a width (height of the right-angled triangle) of 150 mm on the fuel side and a width of 160 mm on the oxygen side. In the parts 6 and 7 provided as current collectors (triangular lobes), waves and knobs were alternately pressed in such a way that the wave fronts each came to lie parallel to the corresponding flow direction of the gaseous medium (CH₄ or O₂). The wavelength was 7 mm, the amplitude on the fuel side 1.6 mm, on the oxygen side 3.2 mm. The knobs in between had a height of 0.4 mm. In this way, electrically conductive contact points 10 and 11 were created with a center distance of approximately 7 mm. In between, holes of 5 mm in diameter were punched for the passage of the gaseous media. Now the sheet metal element 8 was folded by mandrels of 3.2 mm or 1.6 mm radius of curvature by 180 ° in each case. Finally, the entire component 4 was annealed for 2 hours at 1280 ° C. under argon as a protective gas.

Embodiment 6 See Figs. 6 and 7!

The monolithic component 4 had exactly the same area dimensions as that of example 5. An oxide dispersion-hardened noble metal with the following composition was chosen as the material:

Al₂O₃ = 0.8% by weight
Pt = rest

A Pt / Al alloy was first melted, cast into an ingot and processed into a sheet with a thickness of 0.4 mm by rolling. A sheet metal element 8 according to FIG. 7 was punched out of the sheet and brought into the shape described in Example 5 by pressing, punching and bending. The finished component 4 was finally annealed under an O₂ partial pressure of 4 bar for 5 h at a temperature of 1200 ° C. The aluminum oxidized completely to ultrafine Al₂O₃ particles. These dispersoids were very finely distributed in the platinum matrix.

Embodiment 7 See Figs. 9 and 10!

A monolithic component 4 for power transmission was manufactured from an oxide dispersion-hardened noble metal. The projection of the electrode area was a square with a side length of 120 mm. A Pt alloy with MgO as the dispersoid was chosen as the material. The composition was as follows:

MgO = 1.2% by weight
Pt = rest

A Pt / Mg alloy was produced by melt metallurgy, cast into an ingot and processed into a sheet with a thickness of 0.35 mm by hot and cold rolling. A sheet metal element 8 according to FIG. 10 was punched out of this sheet. The resilient lamellae 12 and 13 adjoining the square surface (part 5 acting as separating plate) of 120 mm × 120 mm had a width of 3 mm and a length of 180 mm on the fuel side and a length of 190 mm on the oxygen side. The clear width of the recess lying between two adjacent slats was 4 mm, so that a clearance of 0.5 mm was provided in the finished state. The parts 6 and 7 provided as current collectors (fins 12 and 13 ) were pressed into wave-like structures, a larger number of waves with a smaller amplitude (0.3 mm) having a smaller number of waves with a larger amplitude (1.6 mm) on the fuel side, 3 mm on the oxygen side). The wavelength was 6 mm throughout. The waves from two adjacent lamellae in the finished component were offset by half a wavelength. In this way, contact points 10 and 11 were created, which had a distance of 6 mm in the longitudinal direction of the slats, and a distance of 3.5 mm transversely thereto. The sheet metal element 8 was brought into the shape shown in FIG. 9 by means of thorns by folding. Then the whole component 4 was annealed for 3 h under an O₂ partial pressure of 4 bar for 3 h at a temperature of 1250 ° C. The magnesium completely oxidized to ultrafine, finely divided MgO dispersoids. The latter are particularly stable.

Embodiment 8 See Figs. 9 and 10!

A monolithic component 4 for power transmission was produced from a dispersion-hardened precious metal alloy. The projection of the electrode area was a square with a side length of 100 mm. A Pt / Rh alloy with TiC as the dispersoid was chosen as the material. The composition was as follows:

TiC = 0.05% by weight (approx.0.25% by volume)
Rh = 10% by weight
Pt = rest

The alloy was produced by powder metallurgy. 90% by weight of Pt powder with a maximum particle size of 5 µm and Rh powder with a maximum particle size of 3 µm were mixed with 0.05% by weight of TiC powder with a maximum particle size of 0.6 µm during 24 hours ground under toluene in the attritor and mechanically alloyed. The powder, which was cold worked to saturation, was dried and filled into a capsule made of soft steel, evacuated and welded gas-tight. The encapsulated powder was extruded at a temperature of 1250 ° C with a reduction ratio of 36: 1 to a flat profile 60 mm wide and 8 mm thick. A part of 120 mm in length was sawed off and processed alternately in the longitudinal and transverse directions, first in the warm, then in the cold state on a sheet metal with a thickness of 0.32 mm. A sheet metal element 8 according to FIG. 10 was punched out of the sheet metal. The resilient lamellae 12 and 13 adjoining the square area of 100 mm × 100 mm acting as a separating plate (part 5 ) had a width of 2.8 mm and a length of 160 mm on the fuel side and 170 mm on the oxygen side mm. The clear width between two lamellae was 3.5 mm, so that each side play of 0.35 mm was present in the finished component 4 . The parts 6 and 7 provided as current collectors (lamellae 12 and 13 ) were pressed into structures in which a series of spherical spherical knobs with a height of 0.25 mm each followed a steep sinusoidal wave of 5 mm wavelength. The amplitude of the wave was 1.4 mm on the fuel side and 3.2 mm on the oxygen side, so that on the first one a passage of 2.8 mm clear height for the passage of the CH₄ and on the latter for the O₂ carrier ( Air) was 6.4 mm. The sheet metal element 8 was brought into the shape shown in FIG. 9 by folding. The component 4 now present was annealed for 3 hours at 1350 ° C. under argon as a protective gas.

Embodiment 9 See Figs. 12 and 13!

A monolithic component 4 was manufactured from an oxide dispersion hardened Fe / Cr alloy with the trade name MA 956 (INCO). The alloy had the following composition:

Cr = 20% by weight
Al = 4.5% by weight
Ti = 0.5% by weight
Y₂O₃ = 0.5% by weight
Fe = rest

A sheet metal element 8 was punched out of a commercially available sheet metal of 0.4 mm thickness as shown in FIG . The projection of the electrode area was a square with a side length of 100 mm. The resilient lamellae 12 and 13 adjoining this part 5 were designed triangularly tapering and had a width of 5 mm at their base. The fins 12 had a length of 140 mm on the fuel side, and the fins 13 had a length of 150 mm on the oxygen side. The slats 12 and 13 were cut in such a way that after folding on the finished component 4 there was a lateral play of 0.4 mm between two oppositely directed slats. The parts 6 and 7 (lamellae 12 and 13 ) provided as current collectors were each provided with three longitudinal roof-like elevations by pressing, on the vertices of which a wart of 0.2 mm in height was pressed at a distance of 7 mm. In addition, three steep trapezoidal shafts of 6 mm wavelength were pressed into the slats 12 and 13 for support on the part 5 acting as a separating plate. The amplitude of this trapezoidal wave measured 1.5 mm on the fuel side and 3 mm on the oxygen side. Holes with a diameter of 2 mm had previously been punched into the waves representing the flanks for better distribution of the flowing gaseous media.

Now the part 6 of the sheet metal element 8 acting as a current collector on the fuel side was provided on both sides, the part 7 acting as a current collector on the oxygen side only on the side resting on the oxygen electrode with an intermediate layer of Ni₃Si acting as a diffusion barrier. Likewise, part 5 acting as a separating plate was coated with the same material only on the fuel side. This intermediate layer was applied by sputtering to a thickness of 20 μm. A protective layer (electrical contact layer) of 30 μm thick made of platinum was electrochemically deposited on this intermediate layer on the sides of parts 6 and 7 lying on the electrodes. The sheet metal element 8 coated in this way was then bent along the folding zones 9 by mandrels of 1.5 mm or 3 mm radius of curvature and brought into the final shape (component 4 , FIG. 12). The component 4 was then annealed at a temperature of 850 ° C. for 24 hours in an oxidizing atmosphere. On the parts of element 4 not covered by Ni₃Si nor by Pt, ie on the oxygen side of part 5 and on the side of part 7 facing the O₂ stream, a coherent protective layer of Cr₂O₃ was formed. On the areas covered with an intermediate layer of Ni₃Si (fuel side of part 5 , the CH₄ current side of part 6 ) a protective layer of SiO₂ was formed. The places covered with Pt remained blank. In this way, the entire component 4 is protected from further premature oxidation or carburization, and a long service life can be expected. In order to achieve high heat resistance, component 4 was subjected to recrystallization annealing at 1300 ° C. for 1/2 h.

Embodiment 10 See Fig. 14!

A monolithic component for power transmission was created made of an oxide dispersion hardened nickel-based superalloy manufactured. The alloy had the trade name MA 754 (INCO) and had the following composition:

Cr = 20% by weight
Al = 0.3% by weight
Ti = 0.5% by weight
Fe = 1% by weight
C = 0.05% by weight
Y₂O₃ = 0.6% by weight
Ni = rest

A commercially available sheet of 1 mm thickness was hot-rolled to 0.3 mm and a sheet-metal element 8 similar to FIG. 4 was punched from it. The projection of the electrode area was a square with a side length of 100 mm. The rectangular lobes adjoining this part 5 were each 80 mm wide on the fuel side and 110 mm wide on the oxygen side. The flaps were each slotted perpendicular to the folding zone 9 in such a way that resilient lamellae (similar to 12 or 13 in FIG. 10) were formed with a lateral play of 0.2 mm each. The lamellae were then pressed into sinusoidal waves of 6 mm wavelength in such a way that 2 adjacent waves were offset by half a wavelength. On the fuel side (part 6 ) these waves had an amplitude of 1.6 mm, on the oxygen side (part 7 ) that of 3.2 mm. The entire part 5 , which acts as a separating plate, was coated on both sides and the apex of the shaft of the parts 6 and 7, which act as current collectors, with a Pt layer using the paste method. The paste consisted of a slurry of Pt powder with max. 2 µm particle size in a solvent with residue-free organic binder. The sheet metal element 8 coated in this way was dried at 400 ° C. for 1/2 h and then annealed at 900 ° C. in an oxidizing atmosphere for 20 h. A 5 µm thick intermediate layer consisting of conductive Cr₂O₃ and a more or less coherent Pt surface layer with an average thickness of 15 µm were formed. The coated sheet metal element was then bent around corresponding mandrels and brought into the shape shown in FIG. 14. In this way, a component was created that defies further oxidation both on the oxygen side (O₂ flow) and on the fuel side (CH₄ flow) of carburization. To achieve the highest possible heat resistance, the component was finally subjected to a recrystallization annealing at 1280 ° C. for 1 h.

The invention is not restricted to the exemplary embodiments.

The component 4 for power transmission between adjacent flat, flat, stacked high-temperature fuel cells ( 1; 2; 3 ) with solid electrolyte 1 based on stabilized zirconium oxide, with the oxygen electrode 2 of one fuel cell being electrically connected to the fuel electrode 3 of the next fuel cell and the space between electrodes 2 and 3 is divided by a gas-tight, electrically conductive partition into two, the different gaseous media fuel (CH₄) and oxygen carrier (O₂) leading spaces, consists of a single, multi-folded monolithic sheet metal part, the is shaped in such a way that a central part 5 forms the separating wall and the two outer parts form the fully elastic current collectors 6 and 7 perpendicular to the plate plane of the fuel cell, which collectors form a multiplicity of the electrically conductive points of contact 10 and 11 to the neighboring E. electrodes 2 and 3 ensuring elevations in the form of waves, folds or nubs. The part forming the current collector on each side is preferably rectangular, square or trapezoidal and covers the entire projection of the electrode surface in a coherent manner.

In a first variant, the part that forms the current collector 6 and 7 on each side consists of two opposing rectangular or square halves that buttly meet in the center line of the electrode surface, each covering the projection of half the electrode surface. In a second variant, the part that forms the current collector 6 and 7 on each side consists of two opposing triangular halves that buttly meet in the diagonal of the electrode surface, each covering the projection of half the electrode surface. In a third variant, the part forming the current collector 6 and 7 consists of a multiplicity of narrow, rectangular tongues 12 and 13 , the clear distance between them in the transverse direction is at least equal to the tongue width. In a fourth variant, the part forming the current collector 6 and 7 consists of a multiplicity of triangularly tapering tongues 12 and 13 .

The component is advantageously designed in such a way that the current collectors 6 and 7 also have a large number of elevations in the form of waves, folds or knobs or their negative shape on the side facing away from the electrodes 2 and 3 , these elevations forming on the wall forming the separating wall Support the middle part 5 and guarantee a variety of electrically conductive contact points.

The component preferably consists of a dispersion-hardened precious metal selected from the group Au, Pd or Pt or of an alloy of at least two of these elements or of a dispersion-hardened, largely Al, Si and Ti-free high-chromium nickel or iron-based alloy, the die Points of contact 10 and 11 forming points of the elevations and their immediate surroundings are provided with an electrically conductive Cr₂O₃ intermediate layer and a noble metal surface layer.

The method for producing a component for power transmission is carried out by punching out a sheet metal element 8 from a high-temperature alloy or a heat-resistant dispersion-hardened noble metal such that it is rectangular, square, trapezoidal, triangular or protruding on all sides around a rectangular, square or trapezoidal base area has a plurality of rectangular or triangular tongues 12 and 13 containing flaps which are folded and bent with a bending radius <2 times the sheet thickness by 180 ° C against the base and by cutting the flaps into individual strips before, during or after this operation and / or can be provided with punching and / or pressing with elevations on one or both sides in the form of waves, folds or knobs. The component is preferably made of a sheet element 8 doped with ThO₂, Al₂O₃, MgO, Y₂O₃ or TiC made of Au, an Au / Pd alloy, or made of Pd or Pt or a Pt / Rh alloy in a thickness of 50 µm to 500 µm. In another embodiment, the component is made of a sheet metal element 8 consisting of a heat-resistant, dispersion-hardened, high-chromium Al and Ti-free nickel-base superalloy and, after shaping to form Cr₂O₃, an annealing treatment at 800 to 1000 ° C. for at least 24 hours under an oxidizing atmosphere subjected and provided at the contact points 10 and 11 intended for contact with the electrodes and on the part 5 forming the separating wall with a dense or porous surface layer made of Au or a Pt metal or an alloy of at least two of these elements. In a further embodiment, the component is made of a sheet-metal element 8 consisting of a heat-resistant Ni or Fe base alloy and the latter is provided with a diffusion barrier and after shaping at the contact points 10 and 11 intended for contact with the electrodes and at which the separating points Wall-forming part 5 with a surface layer made of Au or a Pt metal or an alloy of at least two of these elements.

Claims (13)

1. Component ( 4 ) for power transmission between adjacent flat, flat, stacked high-temperature fuel cells ( 1; 2; 3 ) with solid electrolyte ( 1 ) based on stabilized zirconium oxide, each with the oxygen electrode ( 2 ) of the one fuel cell with the Fuel electrode ( 3 ) of the next fuel cell is electrically connected and the space between the electrodes ( 2; 3 ) is divided by a gas-tight, electrically conductive partition into two, the different gaseous media fuel (CH₄) and oxygen (O₂) containing rooms, characterized in that the component ( 4 ) consists of a single, multiply folded monolithic sheet metal part which is shaped in such a way that a central part ( 5 ) separates the wall and the two outer parts form the fully elastic current collectors ( 6; 7 ) form a variety of the electrical conductive contact points ( 10; 11 ) to the adjacent electrodes ( 2; 3 ) ensuring elevations in the form of waves, folds or knobs. 2. Component according to claim 1, characterized in that the one that forms the current collector on one side Part rectangular, square or trapezoidal and the whole projection of the electrode surface is connected covers. 3. Component according to claim 1, characterized in that the current collector ( 6; 7 ) on each side forming part of two opposing, in the center line of the electrode surface butt-meeting rectangular or square halves, each projecting half the electrode surface covers. 4. The component according to claim 1, characterized in that the current collector ( 6; 7 ) on each side forming part of two opposing, in the diagonal of the electrode surface butting triangular halves, each covering the projection of half the electrode surface. 5. The component according to claim 1, characterized in that the part of the current collector ( 6; 7 ) forming a plurality of narrow, rectangular tongues ( 12; 13 ), the clear distance in the transverse direction is at least equal to the tongue width. 6. The component according to claim 1, characterized in that the part of the current collector ( 6; 7 ) forming a plurality of triangularly tapering tongues ( 12; 13 ). 7. The component according to claim 1, characterized in that the current collectors ( 6; 7 ) are designed such that they also on the side facing away from the electrodes ( 2; 3 ) a plurality of elevations in the form of waves, folds or knobs or their Have negative form, these elevations being supported on the central part ( 5 ) forming the dividing wall and guaranteeing a plurality of electrically conductive contact points relative to the latter. 8. The component according to claim 1, characterized in that it is made from a dispersion hardened precious metal  selected from the group Au, Pd or Pt or from one Alloy of at least two of these elements consists. 9. The component according to claim 1, characterized in that it consists of a dispersion-hardened, largely Al, Si and Ti-free high-chromium nickel or iron-based alloy, and that the points of contact ( 10; 11 ) forming the points of the elevations and their immediate Environment are provided with an electrically conductive Cr₂O₃ intermediate layer and a precious metal surface layer. 10. A method for producing a component according to claim 1, characterized in that a sheet metal element ( 8 ) is punched out of a high-temperature alloy or a heat-resistant dispersion-hardened noble metal in such a way that it has a rectangular, square or trapezoidal base on all sides projecting rectangular, square , trapezoidal, triangular or several rectangular or triangular tongues ( 12; 13 ) containing tabs, which are folded and bent with a bending radius <2 times the sheet thickness by 180 ° C against the base and that the tabs before, during or after this operation cut into individual strips and / or provided with punching and / or pressing with elevations on one or both sides in the form of waves, folds or knobs. 11. The method according to claim 10, characterized in that the component consists of a sheet element ( 8 ) doped with Au, an Au / Pd alloy, or made of Pd or Pt or with a dispersoide of ThO₂, Al₂O₃, MgO, Y₂O₃ or TiC a Pt / Rh alloy is manufactured in a thickness of 50 µm to 500 µm. 12. The method according to claim 10, characterized in that the component made of a heat-resistant dispersion-hardened high-chromium Al and Ti-free nickel-base superalloy existing sheet metal element ( 8 ) and after the shaping to form Cr₂O₃ for at least 24 h in an oxidizing atmosphere subjected to an annealing treatment at 800 to 1000 ° C and at the contact points ( 10; 11 ) provided for contact with the electrodes and on the part ( 5 ) forming the separating wall with a dense or porous surface layer made of Au or a Pt metal or an alloy of at least two of these elements is provided. 13. The method according to claim 10, characterized in that the component made of a heat-resistant Ni or Fe base alloy sheet metal element ( 8 ) and the latter covered with a diffusion barrier made of an intermetallic compound and after shaping to the for contact with the contact points ( 10; 11 ) provided on the electrodes and on which the part ( 5 ) representing the separating wall is provided with a surface layer made of Au or a Pt metal or an alloy of at least two of these elements.