JPH01144570A - Solid electrolyte type fuel cell - Google Patents

Abstract

PURPOSE:To reduce the effect of the camber of a structure material due to heat by arranging multiple laminated bodies each constituted of a rectangular flat plate-shaped fuel electrode, a solid electrolyte and an air electrode in the lateral direction and airtightly connecting the fuel electrodes and the air electrodes of the adjacent laminated bodies with interconnectors. CONSTITUTION:Multiple laminated bodies each stacked with three layers of a rectangular flat plate-shaped fuel electrode 2, a solid electrolyte 3 and an air electrode 4 respectively are arranged in line in the lateral direction on a porous substrate 1, the fuel electrodes 2 and the air electrodes 4 of the adjacent laminated bodies are airtightly connected in series by interconnectors 5 to constitute a flat plate type cell 6. The flat plate type cells 6 are arranged in parallel as modules, fuel flows along one face of each flat plate type cell 6, air flows along the other face, thus even if some camber is generated on the flat plate type cell 6, its effect can be reduced.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to improvements in solid oxide fuel cells.

[Prior Art] Solid electrolyte fuel cells operate at a high temperature of about 1000° C., so their constituent materials are mainly ceramics. Therefore, cracks are likely to occur in the structural material due to differences in the coefficients of thermal expansion of the constituent materials. In order to alleviate this problem, the cell shape of conventional solid oxide fuel cells is mostly cylindrical. However, in a cylindrical solid oxide fuel cell,
There is a problem that the power density (electrical output per volume) of the cell is low. This is because in the case of a cylindrical shape, the only effective cell operating surface is the cylindrical surface, and when cells are assembled into a module, there will be a large amount of dead space.

[Problems to be solved by the invention] Therefore, in recent years, similar to phosphoric acid type and molten carbonate type fuel cells, flat cell structures, monolithic types (honeycomb types,
Solid electrolyte fuel cells with a full-gate (full-gate) cell structure are beginning to attract attention.

However, with the flat cell structure, warpage tends to occur in the flat cells, but the fragile structural material, which is mainly made of ceramics, cannot be held down and fixed with strong external force, making it difficult to stack them and collect current. There is a problem that. In addition, the monolithic cell structure has a problem in that thermal stress is generated due to the complicated structure, and the structural material is likely to crack. For this reason, there are major obstacles to putting either structure into practical use.

An object of the present invention is to provide a solid oxide fuel cell that can minimize the effects of warping of structural materials due to heat while taking advantage of the ease of manufacturing and high output density of a flat cell structure.

[Means for Solving the Problems] The solid oxide fuel cell of the present invention comprises a plurality of laminates formed by stacking three layers of a fuel electrode, a solid electrolyte, and an air electrode, each formed in a rectangular flat plate shape, in a horizontal direction. The fuel electrodes and air electrodes of adjacent laminates are arranged in a row, and the fuel electrodes and air electrodes of adjacent laminates are airtightly connected in series by interconnectors.

[Function] According to such a solid oxide fuel cell, a plurality of flat cells having a large area and high output density are arranged in parallel to form a module, and a large number of strip cells are connected in series. Since fuel or air is allowed to flow through the cell, there is little problem even if the flat cell is slightly warped.

Further, by utilizing the relatively low-temperature portion facing the manifold, electrical connection between flat cells can be established with low resistance, and power loss can be reduced.

[Example] Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view showing a flat cell forming a solid oxide fuel cell module according to the present invention, and FIG. 2 is a plan view of FIG. 1. 1 and 2, on a porous substrate 1, a plurality of laminates formed by stacking three layers of a fuel electrode 2, an electrolyte 3, and an air electrode 4, each in the shape of a rectangular flat plate, are arranged in rows in the horizontal direction. The fuel electrodes 2 and air electrodes 4 of adjacent stacked bodies are arranged in a stripe shape and are airtightly connected in series by an interconnector 5 to form a flat cell 6.

These flat cells 6 are arranged in parallel to form a module, and fuel flows along one side of each flat cell 6, and air flows along the other side. Note that the fuel electrode 2 and the air electrode 4 may be arranged in reverse. Further, the areas through which fuel and air flow may be reversed from those shown in FIG.

The porous substrate 1 is made of, for example, C8Z (calcia stabilized zirconia). The fuel electrode 2 is, for example, N itN
It is made of i/ZrO2 cermet and has a film thickness of several tens to 100 mm. The solid electrolyte 3 is made of, for example, YSZ (yttoria stabilized zirconia), and has a film thickness of 50 to 100 mm.
It is about 〇-. The air electrode 4 is made of, for example, LaC00g or LaMn0i, and has a film thickness of 50 to 1000. That's about it. Such a flat cell 6 can be produced by masking or laser etching, thermal spraying, slurry, CVD, P
It can be manufactured by forming each layer by combining film formation by an appropriate method such as a VD method, or by appropriately cutting each constituent material in the form of a green sheet, arranging them, pressing and sintering them.

The state in which such a flat cell 6 is made into a module is shown in the third example.
This will be explained in more detail with reference to the figures and FIG. As shown in FIG. 3, a plurality of flat cells 6 are fixed to the module outer box 7 in a manner that they are arranged in parallel at predetermined intervals. Fuel passage holes 8 and air passage holes 9 are provided between each flat cell 6 in directions orthogonal to each other. A fuel electrode manifold 10, a fuel electrode exhaust gas manifold 11, an air electrode manifold 12, and an air electrode exhaust gas manifold 13 are attached to the four sides of the module outer box 7, respectively, so that fuel and air can flow as shown by the arrows in the figure. It will be done. Further, as shown in FIG. 4, a lead portion 14 connected to the interconnector 5 is formed at the end of each flat cell 6.
An airtight film 15 is formed thereon. The lead parts 14 are connected to each other by a connector 16 at the surface of the module outer box 7 that contacts the manifold, as shown in FIG.

Although FIG. 3 shows an orthogonal type module, by changing the manifold structure, it can also be made into a parallel flow or countercurrent type module.

According to such a solid oxide fuel cell, a plurality of flat cells 6 having a large area and high output density are arranged in parallel on a single substrate 1 to form a module, in which a large number of strip cells are connected in series. Since fuel or air is allowed to flow between them, there is little problem even if the flat cell 6 warps to some extent.

Further, a lead part 14 is provided at the end of the flat cell 6, and the electrical connection of the flat cell 611 is made using the relatively low temperature part facing the manifold. Since the resistance is low at low temperatures, power loss can be reduced. Further, by using such an external electrical connection method, it is possible to connect flat cells in series or in parallel, taking into consideration the reliability, power loss, and electrical balance of each flat cell.

The structure of the solid oxide fuel cell according to the present invention is not limited to that shown in FIG. 1, but may be, for example, shown in FIG. 5 or 6.

FIG. 5 shows a flat cell 6 having the same structure as in FIG. 1 and a flat cell 11 in which the fuel electrode 2 and air electrode 4 are arranged in reverse. It is arranged. According to such a solid oxide fuel cell, unlike the case shown in FIG. 1, the laminates exist in the same direction with respect to the substrate 1 in all flat cells, so thermal expansion and warpage of each flat cell can be avoided. The deformations such as these are almost in the same direction, which is advantageous for sealing with manifolds when modularized.

FIG. 6 uses a flat cell 18 whose basic structure is a waveform. According to such a solid oxide fuel cell, the effective area can be increased and the output density of the module can be further increased.

Furthermore, without using the porous substrate 1, a flat plate consisting of a laminate in which 3WIs of a fuel electrode, a solid electrolyte, and an air electrode are stacked together, and an interconnector that airtightly connects the fuel electrode and air electrode of adjacent laminates in series. By using a flat cell, the thickness of a flat cell can be significantly reduced, resulting in a lightweight module with high power density, and the cost required for a porous substrate can be reduced, as well as inhibiting thermal expansion of electrodes and electrolyte. thermal stress can be alleviated.

[Effects of the Invention] As detailed above, according to the solid oxide fuel cell of the present invention, while taking advantage of the ease of manufacturing and high output density of the flat cell structure, it is possible to suppress the effects of warping of structural materials due to heat. It can be reduced as much as possible.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of a flat cell that constitutes a solid oxide fuel cell module in an embodiment of the present invention, Figure 2 is a plan view of the flat cell, and Figure 3 is a solid state cell using the flat cell. FIG. 4 is an exploded perspective view of an electrolyte fuel cell module, FIG. 4 is a perspective view showing an end of the flat cell, and FIG. 5 is a flat cell constituting a solid oxide fuel cell module in another embodiment of the present invention. FIG. 6 is a cross-sectional view of a flat cell forming a solid oxide fuel cell module in still another embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Porous substrate, 2... Fuel electrode, 3... Solid electrolyte, 4... Air electrode, 5... Interconnector, 6.
17.18...Flat cell, 7...Module outer box, 8...Fuel passage hole, 9...Air passage hole, 10...
- Fuel electrode manifold, 11... Fuel electrode exhaust gas manifold, 12... Air electrode manifold, 13... Air electrode exhaust gas manifold, 14... Lead part, 15.
...Airtight membrane, 16...connector. Applicant's agent Patent attorney Takehiko Suzue Figure 1 Figure 2 Figure 4

Claims (1)

[Claims] A plurality of laminates each consisting of three layers of a fuel electrode, a solid electrolyte, and an air electrode, each formed in a rectangular flat plate shape, are arranged in a row in the horizontal direction, and the fuel electrodes and air electrodes of adjacent laminates are interconnected. Solid electrolyte fuel cells are characterized by being airtightly connected in series using connectors.