DE4113049A1 - Gas feed for high temp. fuel cell stack - uses S=shaped flow path between diametrically opposing corners of fuel cell plates - Google Patents

Abstract

The gas feed allows O2 carrier gas and CH4 fuel gas to be fed between the ceramic, high temp. fuel cell plates, using (Zr, O2) as the fixed electrolyte (1), via channels at the corners of the plates, perpendicular to the plane of the latter, with similar removal of the ballast gas and the reaction products. The gas flow path within each fuel cell extends in a S-shape between diagonally opposing corners, the carrier and fuel gases and the ballast gas and reaction products flowing in the same or opposing directions. ADVANTAGE - Maintains electrode surfaces at constant temp.

Description

Technical area

High-temperature fuel cells for the conversion of chemical Energy into electrical energy. The electrochemical Energy conversion and the devices required for this purpose win thanks to their good efficiency over others Conversion types in importance.

The invention relates to the further development of electrochemical high-temperature cells using of ceramic solid electrolyte as an ion conductor, wherein the cells largely independent of the fuel used should be and grant a space-saving arrangement should.

In the narrower sense, the invention relates to a device to guide the gaseous media gaseous oxidizer (Symbol O₂) and gaseous fuel (symbol CH₄) in at least one stack consisting of plate-shaped planar ceramic high temperature fuel cells the basis of ZrO₂ as a solid electrolyte.  

State of the art

High temperature fuel cells with ceramic solid electrolyte are from numerous publications known. The actual elements for such cells can have a variety of shapes and dimensions. To keep the ohmic voltage losses small, is tried everywhere, the thickness of the electrolyte layer keep as low as possible. Shape and dimensions of the elements also comply with the requirement of possibility the electrical series connection of a plurality of cells, to get to the necessary terminal voltage and the currents comparatively low.

In the case of a stacked arrangement of a plurality of plate-shaped fuel cells similar to the filter press Principle, the current must be perpendicular to the plate plane of the Oxygen electrode of a cell to the fuel electrode the next cell. As essential Components are electrical for this function Connecting links to the electrodes (current collectors) and Separation plates (bipolar plates) required.

The previously known components, arrangements and gas ducts often satisfy with respect to the used Materials, design and fabrication as well as the Long-term behavior does not meet the modern requirements.

Furthermore, the currents must be supplied to the fuel cells gaseous media (symbol O₂ for oxygen carrier z. Air; Symbol CH₄ for gaseous fuel in the form a hydrocarbon, e.g. As methane) directed and be controlled so that the electrode surface as possible constant temperature, the temperature differences  the various components are kept low and a compact, space-saving arrangement can be realized can.

For conventionally guided streams of gaseous media in multi-unit fuel cell assemblies is - regardless of the type of arrangement - in Generally the temperature at the inlet is too low, at the outlet on the other hand, too high. This applies to all known units and arrangements: designs in the form of tubes, honeycombs, Waves or plates.

The known, for fuel cells and their arrangements Draw primitives used in larger associations mostly by a comparatively complicated geometry made the construction of compact, space-saving facilities difficult. In particular, one is missing for optimal Series connection and admission of the single cells with gaseous Media usable configuration that deals with simple Make manufacturing means realize and a compact Block construction allows.

There is therefore a great need for further development, Simplification and rationalization of construction and the production of fluidically functional Basic components and their optimal constructive and production-oriented design.

The prior art, the following publications called:

• O. Antonsen, W. Baukal and W. Fischer, Fuel Cell with Ceramic Electrolyte ", Brown Boveri releases 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, The Hague, Netherlands, October 26-29, 1987.
• - F.J. Pipe, High-Temperature Fuel Cells, Solid Electrolytes, 1987 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, 1989 Tucson, AZ, U.S. Department of Energy.

Presentation of the invention

The invention is based on the object, a device to guide the gaseous media oxygen carrier and Fuel in at least one stack consisting of plate-shaped ceramic high-temperature fuel cells indicate the basis of ZrO₂ as a solid electrolyte, which a uniform temperature distribution in guaranteed all components, fluidically advantageous and geometrically simple and clear sealing conditions creates. The device should be the highest possible Ensure space utilization and easy disassembly enable the entire fuel cell assembly. On cost-effective manufacturing options is value to lay.

This object is achieved in that in the above-mentioned Device per single fuel cell stack at least one each in a corner of a rectangular Fuel cell associated channel for the supply of  Oxygen carrier O₂ and the fuel CH₄ and for the Removal of the ballast gas N₂ and the reaction products CO₂ and H₂O is provided, whose main axis on the plate plane is vertical and - in the direction of the main axis seen - alternately on the oxygen side and on the fuel side of the respective to be acted upon Fuel cell feed openings at two corners of the rectangular Fuel cell base and discharge openings at the remaining two corners of the rectangular fuel cell Base surface, such that the flowing gaseous media in plan view - perpendicular to the Plate plane - describe S-shaped trajectories, wherein the oxygen carrier (O₂) at the entrance to the Fuel cell parallel in opposite directions or parallel in the same direction or across the fuel (CH₄) and midfield the fuel cell in cocurrent or countercurrent or in cross-flow to the fuel (CH₄) moves and the ballast gas (N₂) at the exit from the fuel cell in parallel in opposite directions or parallel in the same direction or transverse to the Reaction products (CO₂, H₂O) moves.

Way to carry out the invention

The invention will be described with reference to the following figures described embodiments described in more detail.

It shows

Fig. 1 is an elevation / section of a fuel cell assembly and the guide of the gaseous media (direct current in the middle),

Fig. 2 is a plan view / section of a fuel cell assembly and the guide of the gaseous media (direct current in the middle),

Fig. 3 is a perspective view of a section of two adjacent fuel cell stacks and the guide of the gaseous media (direct current in the middle),

Fig. 4 is an elevational view / partial cross-section of a detail of two adjacent fuel cell stacks,

Fig. 5 is a plan view / section of four adjacent fuel cell stacks with channels for guiding the gaseous media, fuel side (CH₄),

Fig. 6 is a plan view / section of four adjacent fuel cell stacks with channels for guiding the gaseous media, oxygen side (O₂; N₂),

Fig. 7 is a plan view / section of a plurality of juxtaposed fuel cells stacks with channels for guiding the gaseous media, fuel side (CH₄), direct current in the middle,

Fig. 8 is an elevation / section of a fuel cell assembly and the guide of the gaseous media (counter-current in the middle),

Fig. 9 is a plan view / section of a fuel cell assembly and the guide of the gaseous media (counter-current in the middle),

Fig. 10 is a perspective view of a section of two adjacent fuel cell stacks and the guide of the gaseous media (counter-current in the middle),

Fig. 11 is an elevation / section of a fuel cell assembly and the guide of the gaseous media (cross-flow in the middle),

Fig. 12 is a plan view / section of a fuel cell assembly and the guide of the gaseous media (cross-flow in the middle),

Fig. 13 is a perspective view of a section of two adjacent fuel cell stacks and the guide of the gaseous media (cross-flow in the middle),

Fig. 14 is a plan view / section of a plurality of juxtaposed fuel cells stacks of square cross section with channels for guiding the gaseous media, fuel side (CH₄), cross-flow in the middle,

Fig. 15 is a plan view / section of a plurality of juxtaposed fuel cell stacks rectangular in cross section with channels for guiding the gaseous media, fuel side (CH₄), cross-flow in the midfield.

In Fig. 1 is an elevation / section of a fuel cell assembly and the leadership of the gaseous media (DC in the midfield) is shown. The actual fuel cell consists of the ceramic solid electrolyte 1 of doped stabilized ZrO₂, the porous (positive) oxygen electrode 2 of a La / Mn perovskite and the porous (negative) fuel electrode 3 of a Ni / ZrO₂ cermet. 4 is a gas-tight electrically conductive partition plate, usually made of a metallic material. 5 represents a metallic or insulating spacer frame including elastic seal (the latter not separately drawn). AA represents a horizontal section through the fuel-side chamber: CH₄ stands as a symbol for gaseous fuel in general. CO₂; H₂O is the symbol for the reaction products. Figure 6 shows the trajectories (stylized) of the CH₄ stream on the fuel side (above the plane of the drawing in Figure 2). Figure 7 is the corresponding trajectories of the CO₂ / H₂O stream on the fuel side of the fuel cell. BB represents a horizontal section through the oxygen-side chamber: O₂; N₂ is a symbol of gaseous oxygen carrier (air) in general. N₂ is the symbol of the ballast gas (nitrogen). Fig. 8 illustrates the trajectories (stylized) of the O₂ / N₂ flow on the oxygen side (below the plane of the drawing in Fig. 2) of the fuel cell. Fig . 9 are the corresponding trajectories of the N₂ flow on the oxygen side of the fuel cell.

Fig. 2 shows a plan view / section of a fuel cell assembly and the guidance of the gaseous media (DC in the midfield). This plan corresponds to the horizontal section AA through the fuel side chamber ( Fig. 1). 5 is the spacer frame including elastic seal having at the upper left corner of a rectangular opening for the entry of the CH₄ stream (trajectories 6 ) and at the bottom right corner such for the exit of the CO₂ / H₂O stream (trajectories 7 ) , The S-shaped course of the trajectories (streamlines) is clearly visible. The located below the plane of O₂ / N₂-stream with entry at the top right (trajectories 8 ) and the corresponding N₂-current with exit bottom left (trajectories 9 ) is also shown. It is clear that in the center of the fuel cell, the currents on the fuel side and on the oxygen side move in the same direction, which is indicated by arrowheads: DC principle! At the entrance as at the exit, the streams move in opposite directions.

Fig. 3 is a perspective view of a section of two adjacent fuel cell stacks and the guide of the gaseous media (DC in the midfield). The reference numerals 1 ; 2 ; 3 each represent an actual fuel cell constructed of three layers. 4 is the partition plate 5 of the spacer frames open at two diagonally opposite corners. 6 is the mean trajectory of the CH₄ stream on the fuel side, 8 that of the O₂ / N₂ stream on the oxygen side. Between two adjacent stacks a gas-tight intermediate wall 16 is provided in the form of a ceramic plate.

In FIG. 4 is an elevational view / partial cross-section of a detail of two adjacent fuel cell stacks is shown. The horizontal sections AA and BB correspond to those of FIG. 1. 1 ; 2 ; 3 is a plate-shaped fuel cell, 4 a gas-tight electrically conductive partition plate. 14 represents a vertical guide serving for the gaseous media outer channel body. 15 is a provided for the same purpose inner channel body. The spaces of the gaseous media CH₄ and O₂; N₂ are designated by the corresponding symbols.

In Fig. 5 is a plan view / section of four adjacent fuel cell stacks with channels for guiding the gaseous media, section through the fuel side (CH₄) shown. This plan corresponds to the horizontal section AA ( FIG. 4). The reference numerals 5 and 6 correspond exactly to those of the preceding Fig. 1 to 3. 10 is a vertical channel for the supply of the fuel (symbol CH₄), 11 a corresponding channel for the removal of the reaction products (symbol CO₂, H₂O). 12 is a vertical channel for the supply of the oxygen carrier (symbol O₂; N₂), in this case air. 13 represents a corresponding channel for the removal of the ballast gas (symbol N₂), in the present case nitrogen. The flow direction is perpendicular to the plane of the drawing, directed out of the latter, directed towards the viewer. This is indicated by circles with a central point (arrowhead seen from the front).

Fig. 6 shows a plan / section of four adjacent fuel cell stacks with channels for guiding the gaseous media, section through the oxygen side (O₂, N₂). This plan corresponds to the horizontal section BB ( Fig. 4). 8 is the mean trajectory of the O₂ / N₂ stream on the oxygen side of the fuel cells. All other reference numerals and symbols correspond exactly to those of FIG. 5.

Fig. 7 shows a plan / section of a plurality of juxtaposed fuel cell stacks with channels for guiding the gaseous media, section through the fuel side (CH₄) is: DC in the midfield! In principle, this figure is an extension of Figure 5: Numerous fuel cell stacks are combined into a compact block. The reference numerals correspond to those of FIG. 5.

In Fig. 8 is an elevation / section of a fuel cell assembly and the leadership of the gaseous media (countercurrent in the midfield) is shown. All reference numerals correspond to those of FIG. 1. The guidance of the gaseous media on the fuel side (horizontal section AA) is unchanged from that in FIG . On the oxygen side (horizontal section B-B), however, it is opposite to that of FIG . This is indicated by arrowheads and circles with crosses (arrow seen from behind).

In Fig. 9 is a plan view / section of a fuel cell assembly and the leadership of the gaseous media (countercurrent in the midfield) is shown. This plan corresponds to the horizontal section AA through the oxygen-side chamber ( FIG. 8). The located below the plane of O₂ / N₂ flow occurs here below left (trajectories 8 ) and the corresponding N₂ current occurs at the top right (trajectories 9 ). Everything else corresponds to FIG. 1. In the middle field of the fuel cell, the currents on the fuel side move in opposite directions to those on the oxygen side, which is indicated by arrowheads: Countercurrent principle! At the entrance as well as at the exit the streams move in the same direction.

Fig. 10 is a perspective view of a section of two adjacent fuel cell stacks and the guide of the gaseous media (counter-current in the middle). The representation and the reference numerals correspond exactly to those of Figure 3. The current command on the fuel side (CH₄) is unchanged, whereas that on the oxygen side (O₂; N₂). Just the reverse as shown in Fig 3. The countercurrent principle is made clear by the arrows. ,

Fig. 11 relates to an elevation / section of a fuel cell assembly and the guidance of the gaseous media (cross-flow in the midfield). All the reference numerals correspond to those of Fig. 1. The leadership of the gaseous media on the fuel side (horizontal section AA) is the same as in Fig. 1. On the oxygen side (horizontal section BB), however, it is opposite to that of Fig. 1 by 90 ° in the disk plane turned. This is indicated by arrowheads and circles with dots (arrow seen from the front).

In Fig. 12 is a plan view / section of a fuel cell assembly and the leadership of the gaseous media (cross-flow in the midfield) is shown. This plan corresponds to the horizontal section AA through the fuel-side chamber ( FIG. 11). The located below the plane O₂ / N₂ current occurs here above left (trajectories 8 ), ie in the same corner as the CH₄- power but transverse to the latter and the corresponding N₂- current occurs below right (trajectories 9 ), ie in the same corner as the CO₂ / H₂O stream but across the latter. The remaining details and reference numerals correspond to FIG. 1. In the middle field of the fuel cell, the currents on the fuel side move transversely to those on the oxygen side, which is indicated by arrowheads: Cross-flow principle! At the entrance as well as at the exit, the streams also move across each other.

Fig. 13 shows a perspective view of a section of two adjacent fuel cell stacks and the guide of the gaseous media (cross-flow in the middle). The representation and the reference numerals generally correspond to those of Figure 3. For clarity, the flow guide on the oxygen side. (O₂; N₂) has been retained in the space (corresponds exactly to the Fig. 3), while the current command on the fuel side (CH₄) to 90 ° relative to that in Fig. 3 is offset. The cross-flow principle in the midfield is clearly visible by appropriately drawn arrows. The intermediate wall 16 is omitted in this arrangement.

In Fig. 14 is a plan view / section of a plurality of juxtaposed fuel cells square cross section with channels for guiding the gaseous media, section through the fuel side (CH₄), (cross-flow in the midfield) shown. In principle, the reference numerals correspond to those of FIG. 5. According to the cross-flow principle, a symmetrical arrangement with complete space utilization by the active components is implemented here. No additional channel walls or partitions are required. The channel walls are formed by the respective adjoining part of the insulating spacer frame 5 including elastic seal of each fuel cell. The latter consist of square plates. As a result, all channels are also square and have the same cross-section. In accordance with the different flow rates of the gaseous media, the flow rates in the different channels are also different.

Fig. 15 shows a plan view / section of a plurality of juxtaposed fuel cell stacks rectangular section with channels for guiding the gaseous media, section through the fuel side (CH₄), cross-flow in the center panel. The reference numerals correspond in principle to those of FIG. 5. The channel cross sections are square in order to obtain as low as possible pressure losses through the flow. In order to become more fluidly suitable for the different gas quantities, the channel cross sections are designed differently in size - at least in pairs. The channel cross section for the CH₄ stream (channel 10 ) and for the CO₂ / H₂O stream (channel 11 ) is smaller than that for the O₂ / N₂ stream (channel 12 ) and the N₂ stream (channel 13 ). This reduces the degree of symmetry of the overall cross section of the complete stacking block. The fuel cell or the insulating spacer frame 5 are designed rectangular. As a result, full utilization of space by the active components can be achieved despite the lower degree of symmetry. There are no passive, merely supporting or filling function performing components required. The channel walls are again formed by the respective corresponding part of the insulating spacer frame 5 including elastic seal. The cross-flow principle is illustrated by the arrowheads of the trajectories 6 (CH₄-stream) and 8 (O₂ / N₂-stream).

Embodiment 1 (See Figures 1, 2 and 3)

A fuel cell assembly was constructed as follows: Several of solid electrolyte 1 and electrodes 2 and 3 existing fuel cells were combined with the interposition of spacer frame 5 with separator plates 4 into a stack. The cross-section of the stack (seen perpendicular to the direction of the electric current) was square and measured 100 mm × 100 mm. The solid electrolyte 1 was made of doped stabilized ZrO₂ and had a thickness of 60 microns. The porous (positive) oxygen electrode 2 consisted of a La / Mn perovskite and had a thickness of 70 microns, the porous (negative) fuel electrode 3 of a Ni / ZrO₂ cermet with a thickness of 40 microns. The separator plate 4 and the spacer frames 5 (in the present case without sealing) consist of a nickel-base superalloy with the trade name Nimonic 90 having the following composition:

Cr = 19.5% by weight Co = 16.5% by weight al = 1.45% by weight Ti = 2.45% by weight Mn = 0.30% by weight Si = 0.30% by weight Zr = 0.06% by weight C = 0.07% by weight B = 0.003% by weight Ni = Rest

The separator plate 4 had a thickness of 0.5 mm, the spacer frame 5 on the oxygen side a height of 6 mm, on the fuel side, one of 3 mm. The legs of the L-shaped spacer frame 5 had a width in the plate plane of 8 mm. The longer leg measured outside 100 mm, the shorter 60 mm. The spacer frame 5 were firmly connected on both sides of the partition plate 4 with this over a high-temperature solder to a monolithic whole. The spacer frame 5 were both on the oxygen side as well as on the fuel side depending on lying in the plane of the plate L-shaped boundary surface using a ceramic adhesive with a 0.3 mm thick fleece of Al₂O₃ fibers as a seal (not shown). In this way, a stack of a total of 10 individual fuel cells ( 1 , 2 , 3 ), 9 separating plates 4 , soldered together with their adjacent spacer frame 5 and 2 end plates was assembled.

The stack was according to flow pattern Fig. 2 on the respective oxygen side with air (trajectories 8 ) acted as an oxygen carrier and on the corresponding fuel side with methane CH₄ (trajectories 6 ) as a fuel. The amount of supplied gaseous media was such that the oxygen side of each cell a flow rate of 58.8 cc / s (O₂ + 4 N₂) and the fuel side such a 0.6 cc / s (1/2 CH₄) under standard conditions received. The average velocity in the center field of the separator plate 4 was 11.8 cm / s under standard conditions on the oxygen side, and 0.24 cm / s on the fuel side. The oxygen carrier was supplied to the fuel cells at a temperature of about 650 ° C, the fuel with a temperature of about 450 ° C. According to the flow conditions (DC midfield) left the ballast gas (symbol N₂) the fuel cell with a temperature of about 820 ° C, while the reaction products (symbol CO₂; H₂O) had such of about 950 ° C. The electrical power was about 7 W / cell (0.10 W / cm²).

Embodiment 2 (See Figures 8, 9 and 10)

The fuel cell arrangement basically corresponded to that of Example 1. The main dimensions in the plate plane of 100 mm × 100 mm were the same. Also, the fuel cells made of the electrolyte 1 and the electrodes 2 and 3 had the same dimensions as in Example 1. The partition plate 4 and the adjacent spacer frames 5 (without seal) were made of a single pressed forging and had the shape shown in FIG The thickness of the partition plate 4 was 1.5 mm. The flow area for the gaseous media was unchanged. As a result, the height of the forging (Reference 4 + 5 + 5 ) became 1.5 + 6 + 3 = 10.5 mm. The forging consisted of the nickel-base superalloy with the trade name Nimonic 90.

The stack was acted upon in accordance with flow pattern Fig. 9 with the gaseous media. The volume flows were the same as given in Example 1. The same was true for the inlet temperatures. According to the flow conditions (countercurrent in midfield) the ballast gas (symbol N₂) left the fuel cell at a temperature of about 800 ° C, while the reaction products (symbol CO₂; H₂O) had such of about 900 ° C. The electrical power of the entire stack was 71 W (0.10 W / cm 2), the current 10 A, the cell voltage 0.71 V.

Embodiment 3 (See Figs. 11, 12 and 13)

Basically, the arrangement corresponded to that of Example 1. The cross section of the stack of 10 fuel cells including accessories stack was square (80 mm × 80 mm). The existing of doped ZrO₂ solid electrolyte 1 had a thickness of 70 microns, the oxygen electrode 2 from La / Mn-perovskite one of 50 microns and the fuel electrode 3 of Ni / ZrO₂ cermet one of 30 microns. The separator plate 4 consisted of a 0.5 mm thick sheet of a nickel-base superalloy with the trade name Hastelloy "X" having the following composition:

Cr = 27.0% by weight Co = 1.5% by weight Mo = 9.0% by weight W = 0.6% by weight Mn = 0.50% by weight Si = 0.50% by weight Fe = 18.5% by weight C = 0.10% by weight Ni = Rest

The sintered Al₂O₃ existing L-shaped spacer frame 5 had on the oxygen side a height of 7 mm, on the fuel side such a 2.5 mm. The thighs were 7 mm wide. The longer leg measured outside 80 mm, the shorter 48 mm. The spacer frame 5 were planked on both contact surfaces (fuel cell on the one hand, partition plate on the other hand) with 0.3 mm thick ceramic nonwovens using ceramic adhesive. In one variant, the separator plate-side fleeces have basically been dispensed with and the spacer frames 5 are fastened directly to the separator plate 4 by means of ceramic adhesive.

The stack was acted upon in accordance with flow pattern Fig. 12 with the gaseous oxidizer and the fuel. On the oxygen side, a volume flow of 36.2 cc / s (O₂ + 4 N₂) was supplied per cell and on the fuel side such a 0.36 cc / s (1/2 CH₄) under standard conditions. The average velocity in the center field of the separation plate 4 was 1.02 cm / s under standard conditions on the oxygen side, and 0.14 cm / s on the fuel side. The oxygen carrier was supplied to the fuel cells at a temperature of about 700 ° C, the fuel with a temperature of about 500 ° C. According to the flow conditions (cross-flow in midfield) the ballast gas (symbol N₂) left the fuel cell at a temperature of about 860 ° C, while the reaction products (symbol CO₂; H₂O) assumed such a 970 ° C. The electrical power was about 4.3 W / cell (0.10 W / cm²), the current about 6.1 A.

Embodiment 4 (See Figs. 6 and 7)

It was first compiled according to Example 1, a fuel cell assembly. The stack consisted of 20 cells with accessories and had a square cross section of 100 mm × 100 mm. Separation plate 4 and spacer frame 5 (without seals) formed as in Example 1, a unit formed from the material Nimonic 90. A total of 16 stacks were shown in FIG. 7 with their longitudinal axes parallel juxtaposed and supplemented by correspondingly shaped outer channel body 14 and inner channel body 15 , which were provided with ceramic fleece seals (not shown). To avoid short circuits with irregular thermal expansions, the channel body 14 and 15 were made of sintered Al₂O₃.

In one variant, these channel bodies were made of a heat- and scale-resistant iron-based alloy with the designation Cr Al 20 5 according to German standard with material number 1.4767 executed and on all sides with a ceramic fleece of 0.5 mm thick covered with ceramic adhesive. The material had the following composition:

Cr = 20% by weight al = 5% by weight Si = 0.8% by weight Mn = 0.4% by weight P = 0.045% by weight S = 0.030% by weight C = 0.10% by weight Fe = Rest

The inner channel bodies 15 were made as strips with a cross section of 8 mm × 15 mm, while the outer channel bodies 14 were cast with multiple U-section and mechanically machined at the butt joints to the active part of the cell stacking unit.

The whole, consisting of 16 stacked battery was so loaded by gaseous media that in each case exactly the same conditions prevailed per fuel cell as in Example 1. Taking into account a flow rate of 58.8 cm³ / s (O₂ + 4 N₂) per cell and of 0.6 cm3 / s (1/2 CH₄) per cell under standard conditions, the total volume flow at the bottom of the vertical channel 12 for the oxygen carrier was 4700 cc / s and at the channel 10 for the fuel a total volume flow 48 cc / s. The corresponding mean velocities at the lower entrance were 302 cm / s (channel 12 ) and 4 cm / s (channel 10 ). The flow conditions (DC in the midfield compare Fig. 2) gave the same temperatures as in Example 1. The performance of the entire, consisting of 320 cells battery reached the value of 2240 W.

Embodiment 5 (See Figs. 12 and 14)

Similar to Example 1, a fuel cell assembly was assembled. A single stack consisted of 25 cells with accessories and had a square cross section of 100 mm x 100 mm. The partition 4 consisted of a 0.5 mm thick sheet of Hastelloy "X". The spacer frame 5 consisted of sintered Al₂O₃. The L-shaped legs measured 100 mm and 60 mm and were 8 mm wide. On the oxygen side they had a height of 6 mm, on the fuel side, one of 3 mm. This basically resulted in the same dimensions as in Example 1. The spacer frame 5 were glued directly to the partition plate 4 by means of an elastic ceramic adhesive. On the end faces touching the fuel cells, they were covered with a 0.3 mm thick ceramic fleece. Since the vertical channels 10 , 11 , 12 and 13 for the gaseous media were formed directly by the staggered and stump abutting spacer frame 5 , accounted for the channel body according to Example 4. As shown in FIG. 14, a total of 16 stacks with their longitudinal axes parallel to each other. For each fuel cell, the same geometric conditions prevail as in Example 1. In contrast, the whole battery was fluidically switched so that in the middle of the partition plate 4, the flow conditions as shown in FIG. 12 prevailed (cross flow principle). At a flow rate of 58.8 cc / s (O₂ + 4 N₂) per cell on the oxygen side under standard conditions had to be supplied below per channel 5880 cc / s. On the fuel side, the volume flow was 0.6 cc / s (1/2 CH₄) per cell, with 60 cc / s down per channel. The total power of the battery was 2.8 kW (400 cells), the specific power density about 0.07 kW / dm³ (net).

Embodiment 6 (See Figs. 12 and 15)

Similar to Example 5, a fuel cell assembly was assembled. A single stack consisted of 40 cells with accessories and had a rectangular cross-section of 100 mm x 112.5 mm. The separator plate 4 consisted of a 0.4 mm thick sheet of the material Inconel 690 with the following composition:

Cr = 30% by weight Fe = 9.5% by weight C = 0.03% by weight Ni = Rest

The spacer frame 5 consisted of sintered Al₂O₃. The L-shaped legs had on the outside a length of 112.5 mm and 60 mm and a width of 8 mm. On the oxygen side they had a height of 6 mm, on the fuel side, one of 3 mm. The spacer frames 5 were fixed on the partition plate 4 by means of an elastic ceramic adhesive. On the end faces facing the fuel cells, the spacer frame 5 were pasted with a consisting of Al₂O₃ fiber fleece. There were no additional channel body required as described in Example 5. A total of 9 stacks of individual fuel cells were arranged parallel to one another according to FIG. 15 with their longitudinal axes parallel. In this way, a battery of a total of 360 cells was formed. Therefore, the conditions were similar to those in Example 5, except that the vertical channels for the oxygen carrier and for the fuel had different cross sections. The former measured 52.5 mm × 52.5 mm (27.5 cm²), the latter 40 mm × 40 mm (16 cm²). Technically speaking, the whole battery was switched so that in the middle of the partition plate 4, the flow conditions as shown in FIG. 12 prevailed (cross-flow principle). At a flow rate of 66 cc / s (O₂ + 4 N₂) per cell on the oxygen side under standard conditions below 10560 cc / s were fed per channel. On the fuel side, the volume flow under standard conditions was 0.675 cc / s (1/2 CH₄) per cell, with the channel having to be supplied at 108 cc / s. The total output of the 360 cell battery was approximately 2.84 kW.

The invention is not limited to the embodiments.

The device for guiding the gaseous media gaseous oxygen carrier (symbol O₂, N₂) and gaseous fuel (symbol CH₄) consists of at least one stack of plate-shaped planar ceramic high temperature fuel cells ( 1 , 2 , 3 ) based on ZrO₂ as solid electrolyte 1 , wherein for each fuel cell stack at least one in a corner of a rectangular fuel cell ( 1 ; 2 ; 3 ) arranged channel ( 10 ; 11 ; 12 ; 13 ) for the supply of the oxygen carrier O₂; N₂ ( 12 ) and the fuel CH₄ ( 10 ) and for the discharge of the ballast N₂ ( 13 ) and the reaction products CO₂ and H₂O ( 11 ) is provided, whose main axis is perpendicular to the plate plane and - seen in the direction of the main axis - alternately on the oxygen side and on the fuel side of the respective fuel cell ( 1 ; 2 ; 3 ) to be supplied to at least one at least one corner abutting side in the immediate vicinity of the corner of the rectangular fuel cell base and discharge openings on at least one of at least one of the others Corning abutting side in the immediate vicinity of the corner of the rectangular fuel cell base, such that the flowing gaseous media in plan view - viewed perpendicular to the plate plane - describe S-shaped trajectories, wherein the oxygen carrier (O₂, N₂) at the entrance to the Fuel cell ( 1 , 2 , 3 ) para llel in opposite directions or parallel in the same direction or transverse to the fuel (CH₄) and midfield of the fuel cell ( 1 ; 2 ; 3 ) in cocurrent or in countercurrent or cross-flow to the fuel (CH₄) moves and the ballast gas (N₂) at the outlet of the fuel cell ( 1 ; 2 ; 3 ) in opposite directions in parallel or in the same direction or transverse to the reaction products (CO₂; H₂O) emotional.

In a first embodiment of the device, the supply openings are in the immediate vicinity of two located on the same side of the fuel cell base corners, but on opposite sides and the discharge openings in the immediate vicinity of these supply openings diagonally opposite corners arranged and the oxygen carrier (O₂, N₂) at the entrance to the fuel cell ( 1 , 2 , 3 ) moves parallel in opposite directions to the fuel (CH₄) and in the center of the fuel cell ( 1 , 2 , 3 ) in the DC to the fuel (CH₄) with the ballast gas (N₂) at the outlet of the fuel cell ( 1 ; 2 ; 3 ) moves in parallel opposite to the reaction products (CO₂, H₂O). In a second embodiment of the device, the supply openings are arranged in the immediate vicinity of two corners located on the same side of the fuel cell base and on the same side and the discharge openings in the immediate vicinity of these feed openings diagonally opposite corners and the oxygen carrier (O₂, N₂) at the entrance to the fuel cell ( 1 , 2 , 3 ) moves in the same direction in the same direction to the fuel (CH₄) and in the middle of the fuel cell ( 1 , 2 , 3 ) in countercurrent to the fuel (CH₄), wherein the ballast gas (N₂) at the outlet From the fuel cell ( 1 , 2 , 3 ) in parallel in the same direction to the reaction products (CO₂, H₂O) moves. In a further embodiment of the device, the feed openings are located in the immediate vicinity of a single corner formed by two abutting sides of the fuel cell base and on both sides and the discharge openings in the immediate vicinity of these feed openings diagonally opposite corners and the oxygen carrier (O₂, N₂ ) at the entrance to the fuel cell ( 1 , 2 , 3 ) moves transversely to the fuel (CH₄) and midfield of the fuel cell ( 1 , 2 , 3 ) in short-flow to the fuel (CH₄), wherein the ballast gas (N₂) at the outlet From the fuel cell ( 1 , 2 , 3 ) transversely to the reaction products (CO₂, H₂O) moves.

Claims (4)

1. Device for guiding the gaseous media gaseous oxidizer (symbol O₂, N₂) and gaseous fuel (symbol CH₄) in at least one stack consisting of plate-shaped planar ceramic high-temperature fuel cells ( 1 , 2 , 3 ) based on ZrO₂ as a solid electrolyte ( 1 ), characterized in that per each fuel cell stack at least one in a corner of a rectangular fuel cell ( 1 ; 2 ; 3 ) arranged channel ( 10 ; 11 ; 12 ; 13 ) for the supply of the oxygen carrier (O₂; N₂) ( 12 ) and the fuel CH₄ ( 10 ) and for the discharge of the ballast gas N₂ ( 13 ) and the reaction products CO₂ and H₂O ( 11 ) is provided, whose main axis is perpendicular to the plate plane and - seen in the direction of the main axis - alternately on the oxygen side and on the fuel side of the respective fuel cell ( 1 , 2 , 3 ) to be acted upon supply openings on at least one having at least one corner abutting side in the immediate vicinity of the corner of the rectangular fuel cell base and discharge openings on at least one abutting at least one of the remaining corners side in the immediate vicinity of the corner of the rectangular fuel cell base area, such that the flowing gaseous media in plan view - Seen perpendicular to the plane of the plate - describe S-shaped trajectories, wherein the oxygen carrier (O₂; N₂) in the fuel cell ( 1 , 2 , 3 ) parallel in opposite directions or parallel in the same direction or transverse to the fuel (CH₄) and midfield of the fuel cell ( 1 , 2 , 3 ) in cocurrent or countercurrent or in cross-flow to the fuel (CH₄ Moves and the ballast gas (N₂) at the outlet of the fuel cell ( 1 , 2 , 3 ) in parallel in the same direction or in parallel in the same direction or transversely to the reaction products (CO₂, H₂O) moves. 2. Apparatus according to claim 1, characterized in that the feed openings are arranged in the immediate vicinity of two located on the same side of the fuel cell base corners, but on opposite sides and the discharge openings in the immediate vicinity of these feed openings diagonally opposite corners, and that the oxygen carrier (O₂; N₂) (3 1; 2) for fuel in the direct current (CH₄) moves and which at the inlet into the fuel cell (1; 2 3) in parallel in the opposite direction to the fuel (CH₄) and in the middle of the fuel cell Ballast gas (N₂) at the outlet of the fuel cell ( 1 ; 2 ; 3 ) moves in parallel opposite to the reaction products (CO₂, H₂O). 3. A device according to claim 1, characterized in that the supply openings are arranged in the immediate vicinity of two located on the same side of the fuel cell base corners and on the same side and the discharge openings in the immediate vicinity of these feed openings diagonally opposite corners, and that the oxygen carrier (O₂; N₂) (3 1; 2) for fuel in countercurrent (CH₄) moves and which at the inlet into the fuel cell (1; 2 3) in parallel in the same direction to the fuel (CH₄) and the center of the fuel cell Ballast gas (N₂) at the outlet of the fuel cell ( 1 ; 2 ; 3 ) moves in the same direction in parallel with the reaction products (CO₂, H₂O). 4. The device according to claim 1, characterized in that the supply openings are arranged in the immediate vicinity of a single, formed by two abutting sides of the fuel cell base corner and on both sides and the discharge openings in the immediate vicinity of these feed openings diagonally opposite corners, and that the oxygen carrier (O₂; N₂) moves at the entrance to the fuel cell ( 1 ; 2 ; 3 ) transversely to the fuel (CH₄) and in the middle of the fuel cell ( 1 ; 2 ; 3 ) in short-flow to the fuel (CH₄) and the Ballast gas (N₂) at the outlet of the fuel cell ( 1 , 2 , 3 ) transversely to the reaction products (CO₂, H₂O) moves.