JP6137326B2 - Solid electrolyte fuel cell and manufacturing method thereof - Google Patents

Description

  The present invention generally relates to a solid oxide fuel cell and a method of manufacturing the same, and more particularly, to a solid oxide fuel cell having gas flow passage walls (ribs) for forming a flow passage for anode gas and cathode gas, and the method thereof. It relates to a manufacturing method.

  In general, a flat solid electrolyte fuel cell (also referred to as a solid oxide fuel cell (SOFC)) includes a plurality of flat plate-shaped power generation elements each composed of an anode (negative electrode), a solid electrolyte, and a cathode (positive electrode). And a separator (also referred to as an interconnector) disposed between a plurality of cells. The separator is a fuel gas as an anode gas specifically supplied to the anode in order to electrically connect the plurality of cells in series with each other and to separate the gas supplied to each of the plurality of cells. In order to separate (for example, hydrogen) and oxidant gas (for example, air) as cathode gas supplied to the cathode, it is disposed between the plurality of cells.

  For example, International Publication No. 2008/0444429 (hereinafter referred to as Patent Document 1) discloses a structure of a solid oxide fuel cell.

  The solid electrolyte fuel cell disclosed in Patent Document 1 is disposed between a plurality of cells (power generation element units) each including a fuel electrode layer (anode layer), a solid electrolyte layer, and an air electrode layer (cathode layer). And a gas passage structure having an air passage for supplying air to each cell, and a fuel gas passage for supplying fuel gas to each cell. The cell separation part, the gas passage structure part, and the cell are integrally formed. The main body of the gas passage structure that functions as a manifold is made of an electrical insulator that forms an inter-cell separator that functions as a separator, and is formed continuously with the electrical insulator that forms the inter-cell separator. The portions serving the two functions of the separator and the manifold are formed continuously.

International Publication No. 2008/044429

  In the solid oxide fuel cell disclosed in Patent Document 1, although not clearly shown, fuel gas (anode gas) is supplied to the fuel electrode layer between the inter-cell separator and the fuel electrode layer (anode layer). And a plurality of cathode gas flow passages for supplying air (cathode gas) to the air electrode layer are formed between the inter-cell separator and the air electrode layer (cathode layer). Has been. A plurality of anode gas flow passage walls (ribs) are formed so as to separate each of the plurality of anode gas flow passages from each other, and the plurality of cathode gas flow passages are spaced apart from each other. A plurality of cathode gas flow passage walls (ribs) are formed. Conductive portions are formed on the ribs in order to extract electric power generated in the cells.

  A solid electrolyte fuel cell includes a cell in which a fuel electrode layer, a solid electrolyte layer, and an air electrode layer are stacked, and an inter-cell separator. Then, a solid oxide fuel cell is manufactured by integrally firing the molded body in which the green sheets constituting each layer are laminated. When this molded body is fired, the temperature of each layer increases, whereby each layer thermally expands, and then contracts greatly by sintering. When the firing is finished, the layers are further contracted by cooling the obtained fired body as the temperature is lowered to room temperature. In this series of shrinkage behavior, since the separator and rib are the same material and the cell and separator or rib are different materials, the shrinkage rate of the cell and separator or rib is different, so after cooling to room temperature, The separator acts to pull the rib, or the rib acts to pull the cell or separator. Depending on the degree of the tensile stress, separation or separation occurs between the upper layer and the lower layer that are to be in close contact with each other, or cracks occur in the separator. In this case, particularly when a crack occurs in the separator, there is a problem that the fuel gas leaks and the power generation performance is lowered.

  Therefore, an object of the present invention is to provide a solid oxide fuel cell capable of preventing the occurrence of cracks in a separator and a method for manufacturing the same.

The solid oxide fuel cell according to the present invention includes a cell, an anode gas flow passage layer, a cathode gas flow passage layer, an anode side separation layer, a cathode side separation layer, and a porous layer. The cell is composed of a laminate of an anode layer, a solid electrolyte layer, and a cathode layer. The anode gas flow path layer is laminated on the outside of the anode layer of the cell, and a plurality of anode gases formed at intervals so as to separate each of the plurality of anode gas flow paths that supply the anode gas to the anode layer. It has a flow passage wall. The cathode gas flow passage layer is stacked on the outside of the cathode layer of the cell, and a plurality of cathode gases formed at intervals so as to separate each of the plurality of cathode gas flow passages for supplying the cathode gas to the cathode layer. It has a flow passage wall. The anode side separation layer is laminated outside the anode gas flow passage layer. The cathode side separation layer is laminated outside the cathode gas flow passage layer. The porous layer is disposed between at least one of the plurality of anode gas flow passage walls and the anode-side separation layer and between the plurality of cathode gas flow passage walls and the cathode-side separation layer. The porosity of the porous layer is 10% or more and 60% or less.

In the solid oxide fuel cell of the present invention, between the plurality of anode gas flow passage walls (ribs) and the anode side separation layer, and between the plurality of cathode gas flow passage walls (ribs) and the cathode side separation layer, A porous layer is disposed on at least one of the layers. Thus, the porous layer is interposed between the rib and the separator on at least one of the anode side and the cathode side. For this reason, in the series of shrinkage behavior from firing to cooling, the stress caused by the shrinkage rate of the cell and the separator or rib varies due to the shrinkage and fluctuation of the porous layer interposed between the rib and the separator. Can be relaxed. As a result, stress generated in the separator can be relieved and cracks can be prevented from occurring in the separator. Thereby, the fall of electric power generation performance can be suppressed. Moreover, since the porosity of the porous layer is 10% or more and 60% or less, the occurrence of cracks in the separator can be more effectively prevented.

  In the solid oxide fuel cell of the present invention, the ratio of the thickness of the porous layer to the sum of the thickness of the anode gas flow passage wall or the cathode gas flow passage wall and the thickness of the porous layer is 0.09 or more and 0.00. It is preferable that it is 50 or less.

  By limiting the above ratio to a predetermined range, it is possible to more effectively prevent the separator from cracking.

  Furthermore, in the solid oxide fuel cell of the present invention, the thickness of the anode gas flow passage wall (rib) or the cathode gas flow passage wall (rib) is preferably 100 μm or more and 600 μm or less.

  If the thickness of the rib is within the above range, it is possible to more effectively prevent the separator from cracking.

  In the solid oxide fuel cell of the present invention, the cross-sectional area perpendicular to the laminating direction of the porous layer is substantially the same as the cross-sectional area perpendicular to the laminating direction of the anode gas flow passage wall or the cathode gas flow passage wall. Alternatively, the cross-sectional area perpendicular to the laminating direction of the porous layer may be substantially the same as the cross-sectional area perpendicular to the laminating direction of the anode-side separation layer or the cathode-side separation layer.

  In the solid oxide fuel cell of the present invention, the anode gas flow passage wall (rib), the cathode gas flow passage wall (rib), the anode-side separation layer, the cathode-side separation layer, and the porous layer have the same components. It is preferable to contain.

  In the solid oxide fuel cell of the present invention, the anode gas flow passage wall, the cathode gas flow passage wall, the anode side separation layer, and the cathode side separation layer are preferably formed from the same material.

  A solid oxide fuel cell according to the present invention includes a battery structure including a plurality of cells, an inter-cell separator disposed between the plurality of cells, and an anode gas supply for supplying an anode gas to the plurality of anode gas flow passages. A gas supply flow path structure having a flow path and a cathode gas supply flow path for supplying a cathode gas to the plurality of cathode gas flow paths. The inter-cell separator includes an anode gas flow passage layer, a cathode gas flow passage layer, an anode side separation layer, a cathode side separation layer, and a porous layer. A battery structure part, an inter-cell separation part, and a gas supply flow path structure part are integrally formed.

  By comprising in this way, the part which fulfill | performs the two functions of a separator and a manifold can be formed continuously.

  A method for producing a solid oxide fuel cell according to the present invention is a method for producing a solid oxide fuel cell as described above, wherein pores of a porous layer are formed by eliminating a filler made of carbon or an organic material by firing. To do.

  As described above, according to the present invention, stress generated in the separator can be relieved and cracks can be prevented from being generated in the separator, so that a decrease in power generation performance can be suppressed.

FIG. 1 is an exploded perspective view showing a schematic configuration of a unit module of a solid oxide fuel cell as one embodiment of the present invention. FIG. 2 is a partial cross-sectional view showing a rib and a porous layer disposed between a cell and a cathode side separation layer as one embodiment of the present invention. FIG. 3 is a partial cross-sectional view showing a rib and a porous layer disposed between a cell and an anode-side separation layer as another embodiment of the present invention. FIG. 4 is a partial cross-sectional view showing a rib and a porous layer disposed between a cell and a cathode-side separation layer as another embodiment of the present invention. FIG. 5 is a partial cross-sectional view showing a rib and a porous layer disposed between a cell and an anode side separation layer as still another embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is an exploded perspective view showing a schematic configuration of a unit module 1 of a solid oxide fuel cell as one embodiment of the present invention, in which a stacked molded body (green sheet) before firing is disassembled. Show.

  As shown in FIG. 1, the unit module 1 of the solid oxide fuel cell is configured by stacking the inter-cell separator 20, the cell 10, and the inter-cell separator 20 in order from the bottom. Two inter-cell separators 20 are arranged so as to sandwich a single cell 10. In the solid oxide fuel cell configured by providing a plurality of unit modules in FIG. 1, the inter-cell separator 20 is disposed between the plurality of cells 10.

  The cell 10 comprises a laminate of a fuel electrode layer 11 as an anode layer, a solid electrolyte layer 12 and an air electrode layer 13 as a cathode layer. The inter-cell separation portion 20 disposed on the air electrode layer 13 side of the cell 10 is formed of a laminate of a cathode-side separation layer 21a and an air flow passage layer 23 as a cathode gas flow passage layer. The inter-cell separation portion 20 disposed on the fuel electrode layer 11 side of the cell 10 is formed of a laminate of an anode-side separation layer 21b and a fuel gas flow passage layer 22 as an anode gas flow passage layer.

  In the stacked body of the inter-cell separator 20, the cell 10, and the inter-cell separator 20, there is a gas supply channel structure 30 for supplying anode gas (fuel gas) and cathode gas (air) to the cell 10. Is formed. The gas supply channel structure 30 includes a fuel gas supply channel 31 as an anode gas supply channel for supplying anode gas (fuel gas) to the fuel electrode layer 11, and a cathode gas (air) to the air electrode layer 13. And an air supply channel 32 as a cathode gas supply channel for supplying the gas.

  In the place where the fuel electrode layer 11 of the cell 10 is disposed, the fuel gas supply flow path 31 fits the rectangular flat plate-shaped fuel electrode layer 11 into the U-shaped plate-shaped electric insulator 110 and the fuel insulator 110 and the fuel. It corresponds to a gap formed between the pole layer 11 and is formed of an opening extending in one direction, that is, one elongated rectangular through hole. In the electrical insulator 110, the air supply flow path 32 is formed with a plurality of openings arranged at intervals in one direction, that is, a plurality of circular through holes.

  In the place where the air electrode layer 13 of the cell 10 is disposed, the air supply flow path 32 is formed by fitting the rectangular flat plate-shaped air electrode layer 13 to the U-shaped flat plate-shaped electric insulator 130, and the air insulator 130 and the air electrode. It corresponds to a gap formed between the layers 13 and is formed of an opening extending in one direction, that is, one elongated rectangular through hole. In the electrical insulator 130, the fuel gas supply channel 31 is formed with a plurality of openings arranged at intervals in one direction, that is, a plurality of circular through holes.

  In the solid electrolyte layer 12, each of the fuel gas supply channel 31 and the air supply channel 32 is formed by a plurality of openings arranged at intervals in one direction, that is, a plurality of circular through holes. Yes.

  In the cathode side separation layer 21a and the anode side separation layer 21b, the fuel gas supply flow path 31 and the air supply flow path 32 are each provided with a plurality of openings arranged at intervals in one direction, that is, a plurality of circles. It is formed with a through hole having a shape.

  The green sheet before firing of the fuel gas flow passage layer 22 includes a plurality of fuel gas flow passage formation layers (anode gas flow passage formation layers) 2210 and fuel gas flow passage wall portions (anode gas flow passage wall portions) arranged in a staggered manner. Rib) 222 is fitted to U-shaped flat electrical insulator 220. The fuel gas supply channel 31 corresponds to a gap formed between the electrical insulator 220, the plurality of fuel gas flow channel formation layers 2210, and the fuel gas flow channel wall 222, and extends in one direction. That is, it is formed by one elongated rectangular through hole. The fuel gas flow passage forming layer 2210 disappears after firing, thereby leading to the fuel gas supply channel 31 for supplying the fuel gas to the fuel electrode layer 11 and allowing the fuel gas to flow through the fuel electrode layer 11. It becomes a flow passage (anode gas flow passage). In the electrical insulator 220, the air supply flow path 32 is formed with a plurality of openings arranged at intervals in one direction, that is, a plurality of circular through holes.

  The green sheet before firing of the air flow passage layer 23 includes a plurality of air flow passage formation layers (cathode gas flow passage formation layers) 2310 and air flow passage wall portions (cathode gas flow passage wall portions; ribs) 232 arranged in a staggered manner. Are fitted into a U-shaped flat electrical insulator 230. The air supply flow path 32 corresponds to a gap formed between the electrical insulator 230 and the plurality of air flow passage forming layers 2310 and the air flow passage wall portion 232, and is an opening extending in one direction, that is, It is formed by one elongated rectangular through hole. The air flow passage forming layer 2310 disappears after firing, so that the air flow passage formation layer 2310 communicates with the air supply flow path 32 that supplies air to the air electrode layer 13 and flows air through the air electrode layer 13 (cathode gas). Flow passage). In the electrical insulator 230, the fuel gas supply channel 31 is formed with a plurality of openings arranged at intervals in one direction, that is, a plurality of circular through holes.

  In one embodiment of the solid oxide fuel cell configured as described above, as shown in FIG. 2, substantially the same cross-sectional area is provided between the cell 10 and the cathode-side separation layer 21a on the cathode side. The columnar air flow passage wall portion (cathode gas flow passage wall portion; rib) 232 and the porous layer 40 are arranged so as to contact each other. The air flow passage wall 232 is disposed on the cathode side of the cell 10, that is, is disposed so as to contact the air electrode layer 13 (FIG. 1). The porous layer 40 is disposed in contact with the cathode-side separation layer 21a.

  In another embodiment of the solid oxide fuel cell, as shown in FIG. 3, a columnar fuel gas flow having substantially the same cross-sectional area between the cell 10 and the anode-side separation layer 21b on the anode side. The passage wall portion (anode gas flow passage wall portion; rib) 222 and the porous layer 40 are disposed so as to contact each other. The fuel gas flow passage wall 222 is disposed on the anode side of the cell 10, that is, disposed so as to contact the fuel electrode layer 11 (FIG. 1). The porous layer 40 is disposed in contact with the anode side separation layer 21b.

  In another embodiment of the solid oxide fuel cell, as shown in FIG. 4, on the cathode side, a columnar air flow passage wall portion (cathode gas flow passage wall is provided between the cell 10 and the cathode side separation layer 21a. Part; rib) 232 and the flat porous layer 40 having a larger cross-sectional area than the columnar air flow passage wall part 232 and having substantially the same cross-sectional area as the cathode-side separation layer 21a. Has been placed. The air flow passage wall 232 is disposed on the cathode side of the cell 10, that is, is disposed so as to contact the air electrode layer 13 (FIG. 1). The flat porous layer 40 is disposed so as to be in contact with the cathode-side separation layer 21a.

  In still another embodiment of the solid oxide fuel cell, as shown in FIG. 5, on the anode side, a columnar fuel gas flow passage wall (anode gas flow path) is provided between the cell 10 and the anode side separation layer 21b. (Road wall portion; rib) 222 and a flat porous layer 40 having a cross-sectional area larger than that of the columnar fuel gas flow passage wall portion 222 and having substantially the same cross-sectional area as the anode-side separation layer 21b. It is arranged to touch. The fuel gas flow passage wall 222 is disposed on the anode side of the cell 10, that is, disposed so as to contact the fuel electrode layer 11 (FIG. 1). The porous layer 40 is disposed in contact with the anode side separation layer 21b.

  The cathode side may be configured as shown in FIG. 2 and the anode side may be configured as shown in FIG. 3, or the cathode side may be configured as shown in FIG. 4 and the anode side may be configured as shown in FIG. It may be configured as shown. Only the cathode side may be configured as shown in FIG. 2 or FIG. 4, and only the anode side may be configured as shown in FIG. 3 or FIG.

  As described above, in the solid oxide fuel cell of the present invention, the porous layer 40 is interposed between the rib and the separator on at least one of the anode side and the cathode side. For this reason, in a series of shrinkage behaviors from firing to cooling, the stress caused by the shrinkage variation of the porous layer 40 interposed between the rib and the separator and the shrinkage rate of the cell and the separator or rib being different. Can be relaxed. As a result, stress generated in the separator can be relieved and cracks can be prevented from occurring in the separator. Thereby, the fall of electric power generation performance can be suppressed. In addition, when manufacturing the laminated body of a solid oxide form fuel cell by integral baking, the shrinkage rate of each material is 20 +/- 5%.

  In the solid oxide fuel cell of the present invention, as shown in FIGS. 2 to 5, the thickness Tr of the fuel gas flow passage wall (rib) 222 or the air flow passage wall (rib) 232 and the thickness of the porous layer 40 are shown. The ratio (Tp / (Tp + Tr)) of the thickness Tp of the porous layer 40 to the total with Tp is preferably 9% or more and 50% or less. By limiting the above ratio to a predetermined range, it is possible to more effectively prevent the separator from cracking.

  In the solid oxide fuel cell of the present invention, the porosity of the porous layer 40 is preferably 10% or more and 60% or less. By limiting the porosity of the porous layer 40 to the above range, it is possible to more effectively prevent cracks from occurring in the separator.

  In addition, the pores of the porous layer 40 are formed by mixing and filling a material described later forming the porous layer 40 with carbon or an organic substance, and erasing the filler by firing. The porosity of the porous layer 40 obtained after firing can be adjusted by changing the amount of the carbon component or organic component contained in the material. The electrical insulator 210 forming the main body of the cathode side separation layer 21a and the anode side separation layer 21b is a dense body through which gas cannot pass and is not a porous body. The dense body here has a porosity of 0% or more and 9% or less.

  Furthermore, in the solid oxide fuel cell of the present invention, the thickness Tr of the fuel gas flow passage wall (rib) 222 or the air flow passage wall (rib) 232 is preferably 100 μm or more and 600 μm or less. If the rib thickness Tr is within the above range, it is possible to more effectively prevent the separator from cracking.

  As shown in FIG. 1, conductors 211, 223, and 233 are arranged to take out the electric power generated in the cell 10 and to electrically connect the plurality of cells 10 to each other. The conductor 211 is filled in a plurality of via holes formed in the electric insulator 210 constituting the main body of the anode side separation layer 21b and the cathode side separation layer 21a. The conductor 223 is filled in a plurality of via holes formed in the fuel gas flow passage wall (rib) 222. The conductor 233 is filled in a plurality of via holes formed in the air flow passage wall (rib) 232. In the above case, the fuel gas flow passage wall (rib) 222 and the air flow passage wall (rib) 232 are formed of, for example, an electrically insulating ceramic material, and the anode side separation layer 21b and the cathode side separation layer. It is preferably formed from the same material as the electric insulator 210 constituting the main body 21a, the electric insulator 220 constituting the fuel gas flow passage layer 22, and the electric insulator 230 constituting the air flow passage layer 23. . By comprising in this way, it can form integrally continuously by baking.

  Note that the fuel gas flow passage wall (rib) 222 and the air flow passage wall (rib) 232 need to be functionally conductive, so do not form via holes that fill the conductor. You may form from electroconductive ceramics.

  The electrical insulator 210, the fuel gas flow passage wall (rib) 222, and the air flow passage wall (rib) 232 that constitute the main body of the anode side separation layer 21b and the cathode side separation layer 21a are stabilized zirconia, part Electrolyzed materials such as stabilized zirconia, rare earth element doped ceria, rare earth element doped lanthanum gallate; lanthanum chromite doped with alkaline earth metal elements, rare earth element, niobium or tantalum doped strontium titanate Conductive ceramic materials such as lanthanum ferrate, lanthanum ferrate substituted with aluminum, etc .; electrically insulating ceramic materials such as alumina, magnesia, strontium titanate, and mixed materials thereof.

  The material forming the porous layer 40 includes an electrical insulator 210 that constitutes the main body of the anode side separation layer 21b and the cathode side separation layer 21a, a fuel gas flow passage wall (rib) 222, and an air flow passage wall ( Rib) 232 is preferably the same material as that forming 232, and may be the same material and a material containing nickel oxide. The material of the electric insulator 210 constituting the main body of the anode side separation layer 21b and the cathode side separation layer 21a, and the material forming the fuel gas flow passage wall (rib) 222 and the air flow passage wall (rib) 232 When a different material is a combination of an electrically insulating ceramic material and a conductive ceramic material, due to interdiffusion, the fuel gas flow passage wall (rib) 222 and the air flow passage wall (rib) 232 Conductivity may be impaired. Ceria doped with rare earth elements is chemically stable and can be used in combination with many other materials.

  In summary, in the solid oxide fuel cell of the present invention, the fuel gas flow passage wall (rib) 222, the air flow passage wall (rib) 232, the anode-side separation layer 21b, the cathode-side separation layer 21a, and the porous The quality layer 40 preferably contains the same components. In the solid oxide fuel cell of the present invention, the fuel gas flow passage wall (rib) 222, the air flow passage wall (rib) 232, the anode-side separation layer 21b, and the cathode-side separation layer 21a are the same. It is preferably formed from a material.

  The solid oxide fuel cell according to the present invention includes a battery structure including a plurality of cells 10, an inter-cell separation unit 20 disposed between the plurality of cells 10, and a fuel gas in a plurality of fuel gas flow passages. The fuel gas supply flow path 31 to supply and the gas supply flow path structure part 30 which has the air supply flow path 32 which supplies air to a some air flow path are provided. In this case, the inter-cell separation unit 20 includes a fuel gas flow passage layer 22, an air flow passage layer 23, and a porous layer 40, and includes a battery structure unit including a plurality of cells 10, an inter-cell separation unit 20, and The gas supply flow path structure 30 is integrally formed.

  By comprising in this way, the part which fulfill | performs the two functions of a separator and a manifold can be integrally formed continuously.

The electrical insulators 110, 130, 210, 220, and 230 are, for example, zirconia (ZrO ₂ ) (yttria-stabilized zirconia: YSZ) stabilized with yttria (Y ₂ O ₃ ) added in an amount of 3 mol%. It is formed using zirconia (ZrO ₂ ) (ceria stabilized zirconia: CeSZ) stabilized with ceria (CeO ₂ ) having an addition amount of 12 mol%. The conductors 211, 223, and 233 are formed using, for example, a silver (Ag) -platinum (Pt) alloy, a silver (Ag) -palladium (Pd) alloy, or the like. The solid electrolyte layer 12 includes, for example, zirconia (ZrO ₂ ) (scandia ceria stabilized zirconia stabilized with 10 mol% scandia (Sc ₂ O ₃ ) and 1 mol% ceria (CeO ₂ ) added: ScCeSZ), zirconia (ZrO ₂ ) stabilized with scandia (Sc ₂ O ₃ ) with an addition amount of 11 mol% (scandia stabilized zirconia: ScSZ), and the like. The fuel electrode layer 11 is made of, for example, nickel oxide (NiO), zirconia (ZrO ₂ ) stabilized with scandia (Sc ₂ O ₃ ) added in an amount of 10 mol% and ceria (CeO ₂ ) added in an amount of 1 mol%. It is formed using a mixture with (scandiaceria stabilized zirconia: ScCeSZ) or the like. The air electrode layer 13 is stabilized with, for example, La _0.8 Sr _0.2 MnO ₃ , scandia (Sc ₂ O ₃ ) added in an amount of 10 mol%, and ceria (CeO ₂ ) added in an amount of 1 mol%. It is formed using a mixture with zirconia (ZrO ₂ ) (scandiaceria stabilized zirconia: ScCeSZ) or the like.

(Example)
Hereinafter, as an example of producing the solid oxide fuel cell of the present invention based on the above-described embodiment, the ratio of the thickness Tp of the porous layer to the total of the thickness Tr of the rib and the thickness Tp of the porous layer (Tp / Examples 1 to 15 having different (Tp + Tr)) and comparative examples in which a solid oxide fuel cell without a porous layer was prepared for comparison with the structure of the present invention will be described.

  First, material powders of members (A) to (E) constituting the unit module of the solid oxide fuel cell of the embodiment shown in FIGS. 1 to 5 were prepared as follows.

(A) Fuel electrode layer 11: zirconia stabilized with 60% by weight of nickel oxide (NiO), scandia (Sc ₂ O ₃ ) with an addition amount of 10 mol% and ceria (CeO ₂ ) with an addition amount of 1 mol% ( ZrO ₂ ) (scandiaceria stabilized zirconia: ScCeSZ) with 40% by weight

(B) Solid electrolyte layer 12: zirconia (ZrO ₂ ) (scandia ceria stabilized zirconia stabilized with 10 mol% scandia (Sc ₂ O ₃ ) and 1 mol% ceria (CeO ₂ ) added: ScCeSZ)

(C) The air electrode layer _13: Stable in _{La 0.8} Sr 0.2 _MnO 3 60 wt% and the addition amount 10 mol% of scandia _(Sc 2 _{O 3)} and the addition amount 1 mol% of ceria (CeO ₂₎ With Zirconia Zirconia (ZrO ₂ ) (Scandiaceria Stabilized Zirconia: ScCeSZ) 40 wt%

(D) The electric insulator 110, the electric insulator 130, the electric insulator 210 of the separator 21, the electric insulator 220 of the fuel gas flow passage layer 22, the fuel gas flow passage wall (rib) 222, and the air flow passage layer 23 of electric insulator 230 and air flow passage wall (rib) 232: zirconia (ZrO ₂ ) stabilized with yttria (Y ₂ O ₃ ) added at 3 mol% (yttria stabilized zirconia: 3YSZ)

(E) Porous layer 40: zirconia (ZrO ₂ ) (yttria-stabilized zirconia: 3YSZ) stabilized with yttria (Y ₂ O ₃ ) added in an amount of 3 mol%, or nickel oxide (NiO) 70 wt% Zirconia (ZrO ₂ ) (scandiaceria stabilized zirconia: ScCeSZ) stabilized with 10 mol% scandia (Sc ₂ O ₃ ) and 1 mol% ceria (CeO ₂ ) Mixture (NiO-ScCeSZ)

  First, as shown in FIG. 1, the member (D) was produced as follows.

  Electrical insulation 210 of the cathode side separation layer 21 a and anode side separation layer 21 b, electrical insulation 220 of the fuel gas flow passage layer 22, fuel gas flow passage wall (rib) 222, and electrical insulation of the air flow passage layer 23 For the body 230 and the air flow passage wall (rib) 232, the above-mentioned material powder, polyvinyl butyral binder, and a mixture of ethanol and toluene as the organic solvent (mixing ratio by weight is 1: 4). After mixing, green sheets for each member were produced.

  Electrical insulator 210 of cathode side separation layer 21a and anode side separation layer 21b, fuel gas flow passage wall portion (rib) 222 of fuel gas flow passage layer 22, and air flow passage wall portion (rib) of air flow passage layer 23 ) In the green sheet of 232, as shown in FIG. 1, through holes for forming a plurality of conductors 211, 223, and 233 were formed in the electrical insulator. A conductive paste filling layer for forming the conductors 211, 223, and 233 was prepared by filling these through holes with a paste made of 70 wt% silver and 30 wt% palladium.

  Further, as shown in FIG. 1, the electric insulator 210 of the cathode side separation layer 21a and the anode side separation layer 21b, the electric insulator 220 of the fuel gas flow passage layer 22, and the electric insulator 230 of the air flow passage layer 23. In order to form the fuel gas supply channel 31 and the air supply channel 32, a circular through hole was formed. Five circular through holes were evenly arranged with a diameter of 4.5 mm and an interval of 12 mm.

  In the green sheet of the fuel gas flow passage layer 22, as shown in FIG. 1, a fuel gas flow passage made of polyethylene terephthalate (PET) so as to be connected to a rectangular through hole for forming the fuel gas supply flow passage 31. A formation layer 2210 was formed. The fuel gas flow passage forming layer 2210 disappears after firing, thereby leading to the fuel gas supply flow passage 31 for supplying the fuel gas and serving as a fuel gas flow passage for allowing the fuel gas to flow through the fuel electrode layer 11. . In FIG. 1, three fuel gas flow passages are formed. Actually, however, the fuel gas flow passages 221 having a width of 0.8 mm and a length of 61.5 mm are arranged at intervals of 0.8 mm (see FIG. Many ribs were arranged. The rectangular through hole had a width of 4.5 mm and a length of 61.5 mm.

  In the green sheet of the air flow passage layer 23, as shown in FIG. 1, an air flow passage formation layer 2310 made of polyethylene terephthalate (PET) is connected to a rectangular through hole for forming the air supply flow path 32. Formed. The air flow passage forming layer 2310 disappears after firing, and thereby becomes an air flow passage that leads to the air supply flow path 32 for supplying air and allows air to flow through the air electrode layer 13. In FIG. 1, three air flow passages are formed. Actually, the air flow passages 231 having a width of 0.8 mm and a length of 61.5 mm are arranged at intervals of 0.8 mm (ribs). Many were arranged. The rectangular through hole had a width of 4.5 mm and a length of 61.5 mm.

  Next, with respect to the electrical insulator 130, the electrical insulation material powder, the polyvinyl butyral binder, and a mixture of ethanol and toluene as an organic solvent (mixing ratio by weight is 1: 4) are mixed with the doctor. A green sheet of the electrical insulator 130 was produced by a blade method.

  In the green sheet of the electrical insulator 130, the green sheet of the air electrode layer 13 is fitted with a rectangular gap having a width of 4.5 mm and a length of 61.5 mm in order to form the air supply channel 32. As shown in FIG. 1, a substantially U-shaped sheet was produced. Further, as shown in FIG. 1, in order to form the fuel gas supply channel 31 in the electric insulator 130, a circular through hole having the same size as the above was formed in the green sheet of the electric insulator 130.

  And about the electrical insulator 110, after mixing an electrical insulation material powder, a polyvinyl butyral binder, and a mixture of ethanol and toluene as an organic solvent (mixing ratio is 1: 4 by weight), a doctor blade A green sheet of the electrical insulator 110 was produced by the method.

  In the green sheet of the electric insulator 110, the green sheet of the fuel electrode layer 11 is fitted with a rectangular gap having a width of 4.5 mm and a length of 61.5 mm to form the fuel gas supply channel 31. As shown in FIG. 1, a substantially U-shaped sheet was produced. Further, as shown in FIG. 1, in order to form the air supply channel 32 in the electrical insulator 110, a circular through hole having the same size as described above was formed in the green sheet of the electrical insulator 110.

  Next, green sheets of the air electrode layer 13, the fuel electrode layer 11, and the solid electrolyte layer 12 shown in FIG. 1 were produced as follows.

  After mixing each material powder of the fuel electrode layer 11 and the air electrode layer 13, a polyvinyl butyral binder, and a mixture of ethanol and toluene as an organic solvent (mixing ratio by weight is 1: 4), the doctor The green sheet of the fuel electrode layer 11 and the air electrode layer 13 was produced by the blade method.

  After mixing the material powder of the solid electrolyte layer 12, the polyvinyl butyral binder, and a mixture of ethanol and toluene as an organic solvent (weight ratio is 1: 4), the solid electrolyte layer 12 is mixed by a doctor blade method. A green sheet was prepared. In the green sheet of the solid electrolyte layer 12, as shown in FIG. 1, circular through holes having the same size as described above for forming the fuel gas supply channel 31 and the air supply channel 32 were formed.

  Furthermore, for the green sheet of the columnar or flat porous layer 40 shown in FIG. 2 to FIG. 5, a mixture (by weight ratio) of the above material powder, a polyvinyl butyral binder, and ethanol and toluene as an organic solvent. After mixing the mixing ratio of 1: 4), a columnar or flat green sheet was produced. In addition, the porosity of the porous layer 40 obtained after baking was adjusted by changing the amount of the carbon component or the organic component contained in the material of the green sheet.

  The anode-side separation layer 21b, the fuel gas flow passage layer 22, the support layer 40, the electric insulator 110 in which the fuel electrode layer 11 is fitted, the solid electrolyte layer 12, and the air electrode layer 13 are fitted. The green sheets of the combined electrical insulator 130, airflow passage layer 23, and cathode-side separation layer 21a were laminated in order from the bottom as shown in FIG.

  As shown in Table 1 below, in Examples 1, 2, 5, 8, and 10, as shown in FIG. 4, the cathode-side separation layer 21a and the air flow passage layer 23 (air flow passage wall (rib) 232 are formed. The flat porous layer 40 having a flat plate shape is disposed between the two layers. In Examples 3, 4, 6, 7, and 9, as shown in FIG. 2, a columnar porous material between the cathode-side separation layer 21a and the air flow passage layer 23 (air flow passage wall (rib) 232). Layer 40 was placed. In Examples 10 and 13 to 15, as shown in FIG. 5, a flat plate-like porous layer is provided between the anode-side separation layer 21b and the fuel gas flow passage layer 22 (fuel gas flow passage wall (rib) 222). 40 was placed. In Example 11 and BR> A12, as shown in FIG. 3, a columnar porous layer 40 is provided between the anode-side separation layer 21b and the fuel gas flow passage layer 22 (fuel gas flow passage wall (rib) 222). Arranged.

  As shown in Table 1 below, in Examples 1 to 10 in which the porous layer 40 is disposed between the cathode side separation layer 21a and the air flow passage layer 23 (air flow passage wall (rib) 232), the porous layer 40 is porous. 3YSZ was used as the material for the quality layer 40. In Examples 10-15 in which the porous layer 40 is disposed between the anode-side separation layer 21b and the fuel gas flow passage layer 22 (fuel gas flow passage wall (rib) 222), NiO is used as the material of the porous layer 40. -ScCeSZ was used.

  In this way, cathode side separation layer 21a (thickness after firing: 300 μm) / air flow passage layer 23 / air electrode layer 13 (thickness after firing: 80 μm) / solid electrolyte layer 12 (thickness after firing: 40 μm) A unit module 1 of a solid oxide fuel cell comprising: / fuel electrode layer 11 (thickness after firing: 80 μm) / fuel gas flow passage layer 22 / anode-side separation layer 21b (thickness after firing: 300 μm) was constructed.

  Note that, after firing, the thickness Tp of the porous layer 40, the thickness Tr of the air flow passage layer 23 or the fuel gas flow passage layer 22 (rib) where the porous layer 40 is disposed, the porosity of the porous layer 40, The ratio of the thickness Tp of the porous layer to the sum of the thickness Tr of the rib and the thickness Tp of the porous layer 40 (Tp / (Tp + Tr)) is shown in Table 1 below. It should be noted that the thickness of the air flow passage layer 23 (air flow passage wall (rib) 232) or the fuel gas flow passage layer 22 (fuel gas flow passage wall (rib) 222) is 500 μm at the location where the porous layer is not disposed. It was.

Next, the unit module 1 of the solid oxide fuel cell was crimped by cold isostatic pressing at a pressure of 1000 kgf / cm ² and a temperature of 80 ° C. for 2 minutes. The pressure-bonded body was degreased at a temperature in the range of 400 to 500 ° C, and then fired by holding it at a temperature in the range of 1000 to 1300 ° C for 2 hours. Thus, the solid electrolyte fuel cell samples of Examples 1 to 15 and the comparative example (the area of the planar region in which the fuel electrode layer 11, the solid electrolyte layer 12, and the air electrode layer 13 overlap in the laminate (power generation area) ): 65 mm × 65 mm).

(Evaluation)
A separator gas leak test was performed on the obtained fuel cells of Examples 1 to 15 and Comparative Examples. The gas leak test was performed by introducing nitrogen gas into the fuel cell at a pressure of 50 kPa and measuring the internal pressure with the gas outlet of the fuel cell sealed. If no gas leak occurs, the internal pressure is maintained at 50 kPa, and if a gas leak occurs, the internal pressure drops below 50 kPa. The measurement results are shown in Table 1 below.

  From the above results, it can be seen that the internal pressure could be maintained at 50 kPa in Examples 1 to 15 and the internal pressure was reduced in the comparative example. In the fuel cell of the comparative example, since there was no porous layer, a crack was generated in the separator, and it is considered that the internal pressure was reduced.

  It should be considered that the embodiments and examples disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is shown not by the above embodiments and examples but by the scope of claims, and is intended to include all modifications and variations within the meaning and scope equivalent to the scope of claims. .

1: Unit module 10 of a solid electrolyte fuel cell 10: cell 11: fuel electrode layer 12: solid electrolyte layer 13: air electrode layer 20: inter-cell separation part 21a: cathode side separation layer 21b: anode side separation layer 22: fuel gas Flow path layer 23: Air flow path layer 30: Gas supply flow path structure 31: Fuel gas supply flow path 32: Air supply flow path 40: Porous layers 211, 223, 233: Conductor 222: Fuel gas flow path wall Part (rib)
232: Air flow passage wall (rib)
Tp: thickness of porous layer Tr: thickness of rib

Claims (9)

A cell comprising a laminate of an anode layer, a solid electrolyte layer and a cathode layer;
A plurality of anode gas flow passage walls formed on the outside of the anode layer of the cell and spaced apart from each other to separate each of the plurality of anode gas flow passages supplying the anode gas to the anode layer; An anode gas flow passage layer having;
A plurality of cathode gas flow passage walls formed on the outside of the cathode layer of the cell and spaced apart from each other to separate each of the plurality of cathode gas flow passages for supplying cathode gas to the cathode layer. A cathode gas flow passage layer having;
An anode-side separation layer laminated outside the anode gas flow passage layer;
A cathode-side separation layer laminated outside the cathode gas flow passage layer;
A porous layer disposed between at least one of the plurality of anode gas flow passage walls and the anode-side separation layer and between the plurality of cathode gas flow passage walls and the cathode-side separation layer; ,
Wherein the porous layer porosity of, Ru der 60% or less than 10%, the solid electrolyte fuel cell.   The ratio of the thickness of the porous layer to the sum of the thickness of the anode gas flow passage wall or the cathode gas flow passage wall and the thickness of the porous layer is 0.09 or more and 0.50 or less. Item 2. The solid electrolyte fuel cell according to Item 1. 3. The solid oxide fuel cell according to claim 1, wherein a thickness of the anode gas flow passage wall portion or the cathode gas flow passage wall portion is 100 μm or more and 600 μm or less. The cross-sectional area perpendicular to the stacking direction of the porous layer, the anode gas flow path wall or the cross-sectional area perpendicular to the stacking direction of the cathode gas flow path wall portion to be approximately equal, claims 1 to 3 The solid oxide fuel cell according to any one of the above. The cross-sectional area orthogonal to the stacking direction of the porous layer is substantially identical to the cross-sectional area perpendicular to the stacking direction of the anode-side separator layer or the cathode-side separation layer, any of claims 1 to 3 2. The solid electrolyte fuel cell according to item 1. The anode gas flow path wall portions, the cathode gas flow path wall portion, said anode-side separator layer, the cathode-side separation layer, and said porous layer comprises the same components, claims 1 to 5, The solid oxide fuel cell according to any one of the above. The anode gas flow path wall portions, the cathode gas flow path wall portion, said anode-side separation layer, and the cathode-side separation layer is formed of the same material, any of claims 1 to 6 2. The solid oxide fuel cell according to claim 1. A battery structure including a plurality of the cells;
An inter-cell separator disposed between the plurality of cells;
A gas supply flow path structure having an anode gas supply flow path for supplying an anode gas to the plurality of anode gas flow paths, and a cathode gas supply flow path for supplying a cathode gas to the plurality of cathode gas flow paths. ,
The inter-cell separator includes the anode gas flow passage layer, the cathode gas flow passage layer, the anode side separation layer, the cathode side separation layer, and the porous layer,
The solid oxide fuel cell according to any one of claims 1 to 7 , wherein the battery structure part, the inter-cell separation part, and the gas supply flow path structure part are integrally formed. . A method for producing a solid oxide fuel cell according to any one of claims 1 to 8 , comprising:
A method for producing a solid oxide fuel cell, wherein pores of the porous layer are formed by eliminating a filler made of carbon or an organic substance by firing.

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