WO2009122768A1 - Solid electrolyte fuel cell and method for producing the same - Google Patents

Abstract

Provided is a solid electrolyte fuel cell which can be produced by co-sintering and can prevent cracks resulting from reduction shrinkage behavior during initial power generation. Also provided is a method for producing the solid electrolyte fuel cell. A solid electrolyte fuel cell (100) has a cell (10) composed of a laminate consisting of a fuel electrode layer (11), a solid electrolyte layer (12) and an air electrode layer (13) laminated sequentially, and an isolation portion (21b) for isolating a fuel gas and air supplied to the cell (10) from the outside air. The cell (10) and the isolation portion (21b) are formed by co-sintering. The contact edge of the fuel electrode layer (11) which is in contact with the surface of the solid electrolyte layer (12) in the section of the laminate is not in contact with the contact edge of the isolation portion (21b) which is in contact with the surface of the solid electrolyte layer (12), and is not aligned with the contact edge of the air electrode layer (13) which is in contact with the surface of the solid electrolyte layer (12).

Description

Solid electrolyte fuel cell and manufacturing method thereof

The present invention relates to a solid oxide fuel cell and a method for manufacturing the same.

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.

Conventionally, the separator is formed from a heat-resistant metal material or a conductive ceramic material such as lanthanum chromite (LaCrO ₃ ). When a separator is formed using such a conductive material, a member that performs the functions of electrical connection and gas separation can be formed using a single material.

On the other hand, the separator is joined to the three-layer members constituting the cell, that is, the three-layer members constituting the anode (fuel electrode), the electrolyte and the cathode (air electrode), and leakage of fuel gas and oxidant gas. In order to prevent this, the peripheral portions of the separator and the three-layer member are hermetically sealed.

Also, the laminate composed of separators and cells is connected to a manifold for supplying fuel gas and oxidant gas to each of the plurality of cells. Also in this case, in order to prevent the leakage of the fuel gas and the oxidant gas, the separator and the peripheral portions of the three-layer members and the manifold, and the manifolds are hermetically sealed.

Therefore, as a method for manufacturing a flat-plate solid electrolyte fuel cell that can eliminate the necessity of disposing a seal member between the separator and the cell-manifold, for example, Japanese Patent Laid-Open No. 6-68885 (hereinafter referred to as Patent Document). 1) proposes a method of manufacturing a solid electrolyte fuel cell by integrally sintering (co-sintering) each member of a solid electrolyte, an air electrode, a fuel electrode, a separator (interconnector), and a manifold. . In the solid electrolyte fuel cell proposed in this publication, yttria stabilized zirconia (YSZ) or the like as a solid electrolyte material, lanthanum manganite or lanthanum cobaltite as an air electrode material, NiO-YSZ as a fuel electrode material, Lanthanum chromite is used as a material for the separator.

For example, Japanese Patent Laid-Open No. 2003-132914 (hereinafter referred to as Patent Document 2) discloses a base material whose interconnector structure is made of YSZ and a plurality of conductive vias made of metal housed in the base material. What is comprised is illustrated.
JP-A-6-68885 JP 2003-132914 A

In the solid oxide fuel cell disclosed in Patent Document 1, the material forming the interconnector is lanthanum chromite. Lanthanum chromite and YSZ, which is a solid electrolyte material, are greatly different in heat shrinkage behavior during firing. Therefore, in Patent Document 1, by sandwiching the stress relaxation layer, the stress between the materials resulting from the difference in thermal shrinkage behavior during firing is relaxed by positively cracking the stress relaxation layer, thereby preventing the entire damage. Thus, a solid oxide fuel cell that is integrally sintered is manufactured. However, it is difficult to produce a solid oxide fuel cell without cracks or breakage by integral sintering even if a stress relaxation layer is used.

Incidentally, Patent Document 2 exemplifies using YSZ as a base material for an interconnector. When YSZ is used as the interconnector material instead of lanthanum chromite, the difference in thermal shrinkage behavior during firing between the interconnector and the solid electrolyte can be reduced, so that there is no crack or breakage in the solid oxide fuel cell Can be easily manufactured by integral sintering.

However, even if it is possible to manufacture a solid electrolyte fuel cell by integral sintering while reducing the difference in thermal shrinkage behavior during firing as described above, cracks are likely to occur during initial power generation. It was found by the inventor's experiment. According to the inventor of the present application, the cause of the occurrence of this crack is estimated as follows. Of the materials constituting NiO-YSZ (firing stage) used as the fuel electrode material, NiO (nickel oxide) is reduced to Ni (metallic nickel) by the hydrogen gas supplied to the anode during initial power generation. Is done. This is considered to be caused by stress between materials resulting from this reduction shrinkage behavior.

Accordingly, an object of the present invention is to provide a solid oxide fuel cell that can be manufactured by co-sintering and that can prevent cracks caused by reduction shrinkage behavior during initial power generation, and a method for manufacturing the same. is there.

A solid oxide fuel cell according to the present invention includes a cell composed of a stack of an anode layer, a solid electrolyte layer, and a cathode layer that are sequentially stacked, and the anode gas and cathode gas supplied to the cell are isolated from the outside air. And an isolation part. The cell and the isolation part are formed by co-sintering. The anode layer and the separator are formed so that the contact edge of the anode layer that contacts the surface of the solid electrolyte layer does not contact the contact edge of the separator that contacts the surface of the solid electrolyte layer in the cross section of the laminate. ing. The anode layer and the cathode layer are formed so that the anode layer contact edge is not aligned with the contact edge of the cathode layer contacting the surface of the solid electrolyte layer.

In the solid electrolyte fuel cell of the present invention, the anode layer contact edge that contacts the surface of the solid electrolyte layer is not in contact with the contact edge of the isolation portion that contacts the surface of the solid electrolyte layer. Also, the anode layer contact edge is not aligned with the contact edge of the cathode layer that contacts the surface of the solid electrolyte layer. For these reasons, even if the anode layer exhibits a reduction shrinkage behavior due to the hydrogen gas as the fuel gas supplied to the anode during initial power generation, and stress is generated from the reduction shrinkage behavior, the contact edge of the isolated portion is affected by the stress. Does not work to hold down the anode layer contact edge. Therefore, cracks resulting from the reduction shrinkage behavior during initial power generation can be prevented, and the cell is unlikely to be damaged during initial power generation.

In the solid oxide fuel cell according to the present invention, the separator includes an inter-cell separator disposed between a plurality of cells, and the inter-cell separator includes an anode gas and a cathode gas supplied to each of the plurality of cells. Are preferably formed from an electrical insulator that separates the cells from each other and an electrical conductor that is formed in the electrical insulator and electrically connects a plurality of cells to each other.

The solid oxide fuel cell of the present invention has an anode gas supply path for supplying anode gas to each of the plurality of cells, and a cathode gas supply path for supplying cathode gas to each of the plurality of cells. It is preferable that a gas supply path structure is further provided, and the cell, the inter-cell separation part, and the gas supply path structure are formed by co-sintering.

By configuring in this way, it is possible to integrally form the inter-cell separation part that functions as an interconnector and the gas supply path structure part that functions as a manifold, so that the battery as a whole is sealed against gas. The number of members can be reduced, and as a result, the number of manufacturing steps can be reduced.

Furthermore, in the solid oxide fuel cell according to the present invention, an anode gas flow passage is formed between the inter-cell separator and the anode layer so as to come into contact with the surface of the anode layer, and between the inter-cell separator and the cathode layer. The cathode gas flow passage is preferably formed so as to be in contact with the surface of the cathode layer.

With this configuration, the anode gas can be easily supplied to the surface of the anode layer, and the cathode gas can be easily supplied to the surface of the cathode layer.

In this case, in the solid oxide fuel cell of the present invention, the anode gas flow passage is arranged to extend in the first direction so as to supply the anode gas to the surface of the anode layer, and has a first width. The cathode gas flow passage is disposed to extend in a second direction intersecting the first direction to supply the cathode gas to the surface of the cathode layer, has a second width, the cell, and the anode The gas flow passage and the side wall portion of the cathode gas flow passage are formed by co-sintering, where x is the first width of the anode gas flow passage and x is the second width of the cathode gas flow passage. y preferably has a relationship of x ≧ 0.5 mm, y ≧ 0.5 mm, and x + 3y ≦ 8 mm.

By configuring in this way, in the solid electrolyte fuel cell of the type in which the flow of the anode gas and the flow of the cathode gas are orthogonal (cross flow type), the anode layer and the solid constituting the cell by the heat shrinkage behavior during firing The amount of warpage generated in the laminate of the electrolyte layer and the cathode layer can be suppressed, and as a result, both the pressure loss in the anode gas flow passage and the cathode gas flow passage can be suppressed.

A method for manufacturing a solid oxide fuel cell according to the present invention is a method for manufacturing a solid oxide fuel cell having any one of the above-described features, wherein an anode layer contact edge is formed on a disappeared material that disappears by heating. The anode layer so that the anode contact edge and the separator contact edge do not contact after sintering by filling between the material to be formed and the material forming the separator contact edge and then co-sintering And forming an isolation part.

By manufacturing in this way, the anode layer and the isolation part can be easily formed so that the anode layer contact edge and the isolation part contact edge do not contact each other.

As described above, according to the present invention, since it can be manufactured by co-sintering and cracks caused by reduction shrinkage behavior at the time of initial power generation can be prevented, the cell is less likely to be damaged at the time of initial power generation. An electrolyte fuel cell can be obtained.

1 is a plan view showing a schematic configuration of a unit module of a solid oxide fuel cell of a type (parallel flow type) in which fuel gas and air flow in the same direction as Embodiment 1 of the present invention. FIG. FIG. 2 is a cross-sectional view showing a cross section viewed from the direction along the line II-II in FIG. 1 as a schematic configuration of a solid oxide fuel cell including a plurality of unit modules of a parallel flow type solid oxide fuel cell. FIG. 3 is a cross-sectional view showing a cross section seen from the direction along line III-III in FIG. 1 as a schematic configuration of a solid oxide fuel cell including a plurality of unit modules of a parallel flow type solid oxide fuel cell. FIG. 4 is a cross-sectional view showing a cross section viewed from a direction along line IV-IV in FIG. 1 as a schematic configuration of a unit module of a parallel flow type solid oxide fuel cell. It is a top view which shows the schematic structure of a solid oxide form fuel cell as Embodiment 2 of this invention. FIG. 6 is a cross-sectional view showing a cross section seen from the direction along the line VI-VI in FIG. 5 as a schematic configuration of a solid oxide fuel cell including a plurality of unit modules. FIG. 6 is a cross-sectional view showing a cross section viewed from a direction along the line VII-VII in FIG. 5 as a schematic configuration of a solid oxide fuel cell including a plurality of unit modules. FIG. 6 is a plan view showing a schematic configuration of a solid oxide fuel cell as Embodiment 3 of the present invention. FIG. 9 is a cross-sectional view showing a cross section viewed from a direction along the line IX-IX in FIG. 8 as a schematic configuration of a solid oxide fuel cell including a plurality of unit modules. FIG. 9 is a cross-sectional view showing a cross section seen from a direction along the line XX in FIG. 8 as a schematic configuration of a unit module of a solid oxide fuel cell as Embodiment 3 of the present invention. It is a fragmentary sectional perspective view showing one cell which constitutes a unit module of a cross flow type solid oxide fuel cell. It is a top view which shows arrangement | positioning of the gas flow path in the unit module of the cross-flow type solid oxide fuel cell shown by FIG. It is sectional drawing which shows the part which comprises a solid oxide form fuel cell support structure. It is a figure which shows the relationship between the pressure loss of the air flow path measured in Example 2, and the fuel gas flow path width and the air flow path width. It is a figure which shows the relationship between the pressure loss of the air flow path measured in Example 3, and the fuel gas flow path width and the air flow path width. It is a figure which shows the relationship between the pressure loss of the airflow path measured in Example 2, and ratio of an airflow path width and a fuel gas flow path width.

Explanation of symbols

11: Fuel electrode layer, 11a: Gap, 12: Solid electrolyte layer, 13: Air electrode layer, 20: Solid electrolyte fuel cell support structure, 21: Electrical insulator, 21a: Inter-cell separator, 21b: Isolator 21c: gas supply path structure, 22: electric conductor, 23: fuel gas supply path, 23a: fuel gas flow path, 24: air supply path, 24a: air flow path, 100, 200, 300: solid electrolyte type Fuel cell.

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

(Embodiment 1)
FIG. 1 is a plan view showing a schematic configuration of a unit module of a solid oxide fuel cell of a type (parallel flow type) in which fuel gas and air flow in the same direction as Embodiment 1 of the present invention. FIG. 2 is a cross-sectional view showing a cross section seen from the direction along the line II-II in FIG. 1 as a schematic configuration of a solid electrolyte fuel cell having a plurality of unit modules of a parallel flow type solid oxide fuel cell. It is. FIG. 3 is a cross-sectional view showing a cross section viewed from the direction along the line III-III in FIG. 1 as a schematic configuration of a solid oxide fuel cell having a plurality of unit modules of a parallel flow type solid oxide fuel cell. It is.

FIG. 1 shows a schematic configuration of a unit module of a solid oxide fuel cell as one embodiment 1 of the present invention. In particular, a fuel electrode layer 11, a solid electrolyte layer 12, an air electrode layer 13 are shown. The planar arrangement is shown.

As shown in FIGS. 2 and 3, the solid oxide fuel cell 100 including a plurality of unit modules (solid electrolyte fuel cell modules) of a solid oxide fuel cell includes a solid oxide fuel cell support structure (hereinafter, “ A support structure 20). A plurality of unit modules are laminated inside the support structure 20. In each unit module, a fuel electrode layer 11 having a thickness of 100 to 300 μm as an anode layer constituting the cell 10, and a thickness. Is formed by sequentially laminating a solid electrolyte layer 12 having a thickness of 10 to 50 μm and an air electrode layer 13 having a thickness of 100 to 300 μm as a cathode layer. In FIG. 2, the unit module is configured by laminating the air electrode layer 13, the solid electrolyte layer 12, and the fuel electrode layer 11 sequentially in the upward direction inside the support structure 20. The unit module may be configured by sequentially laminating the fuel electrode layer 11, the solid electrolyte layer 12, and the air electrode layer 13 in the upward direction.

The solid oxide fuel cell 100 has a plurality of cells 10 and is arranged so that a current collector plate 30 having a thickness of 10 to 20 μm is electrically connected to the cell located at the uppermost position via a support structure 20. In addition, a current collector plate 40 having a thickness of 10 to 20 μm is disposed so as to be electrically connected to the cell located at the bottom via the support structure 20. Each of the plurality of cells 10 includes a fuel electrode layer 11, a solid electrolyte layer 12, and an air electrode layer 13 that are sequentially stacked. The support structure 20 includes an isolation part 21b including an inter-cell isolation part 21a having a thickness of about 100 μm arranged between the plurality of cells 10 and a gas supply path structure part 21c.

The inter-cell separator 21 a includes an electrical insulator 21 that separates the fuel gas as the anode gas and the air that is the oxidant gas as the cathode gas supplied to each of the plurality of cells 10. And a plurality of electrical conductors 22 electrically connecting the plurality of cells 10 to each other. The current collector plate 30 is electrically connected to the fuel electrode layer 11 of the uppermost cell through the electric conductor 22, and the current collector plate 40 is electrically connected to the air electrode layer 13 of the lowermost cell through the electric conductor 22. Has been.

The isolation part 21b is formed from the electrical insulator 21 so as to isolate the fuel gas and air supplied to each of the plurality of cells 10 from the outside air.

As shown in FIGS. 1 to 3, in the solid oxide fuel cell 100, the fuel gas supply path 23 is arranged so as to contact a part of one side surface of each fuel electrode layer 11 of the plurality of cells 10. Has been. The air supply path 24 is disposed so as to contact a part of one side surface of the air electrode layer 13 of each of the plurality of cells 10. The fuel gas is supplied through the fuel gas supply path 23, and the air is supplied through the air supply path 24. The fuel gas and air flow in the same direction from left to right in FIG.

As shown in FIGS. 2 and 3, the main body of the gas supply path structure 21c, that is, the wall part forming the fuel gas supply path 23 and the air supply path 24, is an electrical insulator 21 that forms the inter-cell separation part 21a. And is formed continuously with the electrical insulator 21 forming the inter-cell separation portion 21a. The electrical insulator that forms the isolation portion 21b is also made of the same electrical insulator as the electrical insulator 21 that forms the inter-cell isolation portion 21a, and is formed continuously with the electrical insulator 21 that forms the inter-cell isolation portion 21a. Yes.

The electrical insulator 21 is made of, for example, zirconia (ZrO ₂ ) (yttria stabilized zirconia: YSZ) stabilized with yttria (Y ₂ O ₃ ) with an addition amount of 3 mol%, or ceria with an addition amount of 12 mol% (YSZ). It is formed using zirconia (ZrO ₂ ) (ceria stabilized zirconia: CeSZ) stabilized with CeO ₂ ).

The electric conductor 22 may be, for example, a silver (Ag) -platinum (Pt) alloy, a silver (Ag) -palladium (Pd) alloy, or the like, or lanthanum chromite (LaCrO ₃ ) to which alkaline earth metal is added, lanthanum ferrate ( LaFeO ₃ ).

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 11 mol% scandia (Sc ₂ O ₃ ) (scandia stabilized zirconia: ScSZ), or yttria (Y ₂ O ₃ ) with 8 mol% addition It is formed using stabilized zirconia (ZrO ₂ ) (yttria stabilized zirconia: YSZ) or 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%. (Scandiaceria stabilized zirconia: ScCeSZ) or a mixture with zirconia (ZrO ₂ ) (yttria stabilized zirconia: YSZ) stabilized with 8 mol% of yttria (Y ₂ O ₃ ) added. The

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%. Zirconia (ZrO ₂ ) (scandiaceria stabilized zirconia: ScCeSZ) or a mixture with zirconia (ZrO ₂ ) (yttria stabilized zirconia: YSZ) stabilized with 8 mol% of yttria (Y ₂ O ₃ ) added, etc. It is formed using. Alternatively, La _0.8 Sr _0.2 Co _0.2 Fe _0.8 O ₃ may be used instead of La _0.8 Sr _0.2 MnO ₃ .

The current collector plates 30 and 40 are made of, for example, silver (Ag).

In the solid oxide fuel cell support structure 20 of the present invention configured as described above, the main body of the gas supply path structure portion 21c that functions as a manifold, and the isolation portion 21b that separates fuel gas and air from the outside air are provided. Since it is formed of an electrical insulator 21 that forms an inter-cell separation portion 21a that functions as a separator, and is formed continuously with the electrical insulator 21 that forms the inter-cell separation portion 21a, the two functions of a separator and a manifold are provided. The part which fulfills is formed continuously. For this reason, the sealing member between separators and a cell-manifold becomes unnecessary. Thereby, the sealing performance with respect to the gas as the whole battery can be improved, the number of members can be reduced, and as a result, the number of manufacturing steps can be reduced.

The solid oxide fuel cell module according to the present invention is provided on the surface of the solid oxide fuel cell support structure 20 having the above-described features and the inter-cell separation portion 21a of the solid oxide fuel cell support structure 20. The cell 10 is provided with a disposed air electrode layer 13, a solid electrolyte layer 12 formed on the air electrode layer 13, and a fuel electrode layer 11 formed on the solid electrolyte layer 12. Since it is supported by the inter-cell separator 21a of the battery support structure 20, the thickness of the solid electrolyte layer 12 can be reduced to, for example, 100 μm or less. As a result, the electrical resistance of the solid electrolyte layer 12 can be lowered.

Further, in the solid electrolyte fuel cell of the present invention, the material constituting the solid electrolyte layer 12 and the electrical insulator 21 contains stabilized zirconia or partially stabilized zirconia as a main component, so that a solid oxide fuel cell support structure is provided. Since the difference in coefficient of thermal expansion can be reduced between the material constituting the electrical insulator 21 of the body 20 and the material constituting the solid electrolyte layer 12, even if a heat cycle is given during operation, etc. Since the thermal stress acting on the electrolyte layer 12 is small, the destruction of the solid electrolyte layer 12 due to the thermal stress can be suppressed.

Further, since the sintering behavior can be made closer to the material constituting the electric insulator 21 of the solid electrolyte fuel cell support structure 20 and the material constituting the solid electrolyte layer 12, the solid oxide fuel cell support structure The electrical insulator 21 and the solid electrolyte layer 12 of the body 20, and thus the electrical insulator 21 of the solid electrolyte fuel cell support structure 20 and the cell 10 including the solid electrolyte layer 12 can be manufactured by co-sintering. That is, the cell 10, the inter-cell separation part 21a, the isolation part 21b, and the gas supply path structure part 21c are integrally formed by co-sintering.

As described above, when the material constituting the solid electrolyte layer 12 and the electrical insulator 21 contains stabilized zirconia or partially stabilized zirconia as a main component, the inter-cell separator 21a, the separator 21b, and the gas supply path structure Since the difference in heat shrinkage behavior during firing between the material constituting 21c and the solid electrolyte layer 12 can be reduced, it is easy to manufacture a solid electrolyte fuel cell free from cracks and breakage by co-sintering become.

However, even if a solid oxide fuel cell can be manufactured by co-sintering by reducing the difference in thermal shrinkage behavior during firing between materials as described above, cracks are likely to occur during initial power generation. A mixture of NiO (nickel oxide) used as the material of the fuel electrode layer 11 and stabilized zirconia or partially stabilized zirconia (firing stage) with hydrogen gas as the fuel gas supplied to the fuel electrode layer 11 during initial power generation Of these materials, NiO (nickel oxide) is reduced to Ni (nickel metal). The stress between the materials resulting from this reduction shrinkage behavior is considered to be the cause of the crack.

FIG. 4 is a cross-sectional view showing a cross section seen from the direction along line IV-IV in FIG. 1 as a schematic configuration of a unit module of a parallel flow type solid oxide fuel cell. In FIG. 4, (A) and (B) show comparative forms I and II for the present invention, and (C), (D) and (E) show embodiments I, II and III of the present invention.

As shown in FIG. 4A, there is no gas flow passage formed of a groove, an opening, or the like for flowing the fuel gas from the fuel gas supply path 23 to the surface of the fuel electrode layer 11. In addition, a gas flow path composed of a groove, an opening, or the like is not formed to allow air to flow from the air supply path 24 to the surface of the air electrode layer 13.

In this comparative form I, in the cross section of the laminate of the fuel electrode layer 11, the solid electrolyte layer 12, and the air electrode layer 13, the contact edge of the fuel electrode layer 11 that contacts the surface of the solid electrolyte layer 12, in other words, the solid electrolyte layer The outer wall end surface of the fuel electrode layer 11 reaching the surface of 12 is in contact with the contact edge of the isolation portion 21b that surrounds the vicinity of the contact edge of the fuel electrode layer 11 and contacts the surface of the solid electrolyte layer 12; In other words, the fuel electrode layer 11 and the isolating portion 21b are formed so as to be in contact with the inner wall end face of the isolating portion 21b reaching the surface of the solid electrolyte layer 12 so as to coincide with each other. In addition, the contact edge or outer wall end face of the fuel electrode layer 11 is aligned or aligned with the contact edge of the air electrode layer 13 in contact with the surface of the solid electrolyte layer 12, in other words, the solid electrolyte layer 12. The fuel electrode layer 11 and the air electrode layer 13 are formed so as to be aligned or aligned with the outer wall end face of the air electrode layer 13 reaching the surface.

In the comparative form I configured as described above, it has been found by experiments of the present inventor that cracks are likely to occur at the contact edge of the fuel electrode layer 11 in contact with the surface of the solid electrolyte layer 12 during initial power generation.

Further, as shown in FIG. 4B, in order to distribute the fuel gas from the fuel gas supply path 23 to the surface of the fuel electrode layer 11, the fuel electrode is interposed between the inter-cell separator 21 a and the fuel electrode layer 11. A plurality of fuel gas flow passages 23 a are formed so as to contact the surface of the layer 11. Specifically, in this embodiment, a fuel gas flow passage 23 a including a plurality of openings is formed in the fuel electrode layer 11 so as to be in contact with the inner surface of the fuel electrode layer 11. Further, in order to circulate air from the air supply path 24 to the surface of the air electrode layer 13, a plurality of air flows so as to contact the surface of the air electrode layer 13 between the inter-cell separation part 21 a and the air electrode layer 13. A path 24a is formed. Specifically, in this embodiment, an air flow passage 24 a including a plurality of openings is formed inside the air electrode layer 13 so as to contact the inner surface of the air electrode layer 13.

In this comparative embodiment II, in the cross section of the laminate of the fuel electrode layer 11, the solid electrolyte layer 12, and the air electrode layer 13, the contact edge of the fuel electrode layer 11 that contacts the surface of the solid electrolyte layer 12, in other words, the solid electrolyte layer The outer wall end surface of the fuel electrode layer 11 reaching the surface of 12 is in contact with the contact edge of the isolation portion 21b that surrounds the vicinity of the contact edge of the fuel electrode layer 11 and contacts the surface of the solid electrolyte layer 12; In other words, the fuel electrode layer 11 and the isolating portion 21b are formed so as to be in contact with the inner wall end face of the isolating portion 21b reaching the surface of the solid electrolyte layer 12 so as to coincide with each other. In addition, the contact edge or outer wall end face of the fuel electrode layer 11 is aligned or aligned with the contact edge of the air electrode layer 13 in contact with the surface of the solid electrolyte layer 12, in other words, the solid electrolyte layer 12. The fuel electrode layer 11 and the air electrode layer 13 are formed so as to be aligned or aligned with the outer wall end face of the air electrode layer 13 reaching the surface.

It has been found through experiments by the inventors of the present application that even in the comparative example II configured as described above, cracks are likely to occur at the time of initial power generation at the contact edge of the fuel electrode layer 11 in contact with the surface of the solid electrolyte layer 12.

As shown in FIG. 4C, in the embodiment I of the present invention, a gas flow path including a groove and an opening is formed to circulate the fuel gas from the fuel gas supply path 23 to the surface of the fuel electrode layer 11. It has not been. In addition, a gas flow path composed of a groove, an opening, or the like is not formed to allow air to flow from the air supply path 24 to the surface of the air electrode layer 13.

In the embodiment I, in the cross section of the laminate of the fuel electrode layer 11, the solid electrolyte layer 12 and the air electrode layer 13, the contact edge of the fuel electrode layer 11 contacting the surface of the solid electrolyte layer 12, in other words, the solid electrolyte layer. The outer wall end surface of the fuel electrode layer 11 that reaches the surface of 12 surrounds the vicinity of the contact edge of the fuel electrode layer 11 and does not contact the contact edge of the isolation portion 21b that contacts the surface of the solid electrolyte layer 12. Thus, the fuel electrode layer 11 and the isolating portion 21b are formed so as not to coincide with each other, in other words, so as not to contact the inner wall end face of the isolating portion 21b reaching the surface of the solid electrolyte layer 12. . In this embodiment, in order to realize the configuration as described above, the contact edge or inner wall end surface of the isolation part 21b is separated from the contact edge or outer wall end surface of the fuel electrode layer 11, There is a gap 11 a between the contact edge or inner wall end surface of the isolation part 21 b and the contact edge or outer wall end surface of the fuel electrode layer 11. The gap 11a may be filled with a material different from that of the electrical insulator 21 forming the isolation part 21b.

Further, the contact edge or the outer wall end face of the fuel electrode layer 11 is not aligned with the contact edge of the air electrode layer 13 that contacts the surface of the solid electrolyte layer 12, in other words, the solid electrolyte. The fuel electrode layer 11 and the air electrode layer 13 are formed so as not to align with the outer wall end face of the air electrode layer 13 that reaches the surface of the layer 12 so as not to align. In this embodiment, in order to realize the configuration as described above, the contact edge or inner wall end surface of the isolation portion 21b is aligned or aligned with the contact edge or outer wall end surface of the air electrode layer 13. In addition, the isolation part 21b and the air electrode layer 13 are formed.

In the embodiment I configured as described above, it is possible to prevent the occurrence of cracks during initial power generation at the contact edge of the fuel electrode layer 11 in contact with the surface of the solid electrolyte layer 12. I understood.

As shown in FIG. 4D, in Embodiment II of the present invention, in order to circulate the fuel gas from the fuel gas supply path 23 to the surface of the fuel electrode layer 11, the inter-cell separator 21a and the fuel electrode layer 11 are provided. A plurality of fuel gas flow passages 23 a are formed so as to be in contact with the surface of the fuel electrode layer 11. Specifically, in this embodiment, a fuel gas flow passage 23 a including a plurality of openings is formed in the fuel electrode layer 11 so as to be in contact with the inner surface of the fuel electrode layer 11. Further, in order to circulate air from the air supply path 24 to the surface of the air electrode layer 13, a plurality of air flows so as to contact the surface of the air electrode layer 13 between the inter-cell separation part 21 a and the air electrode layer 13. A path 24a is formed. Specifically, in this embodiment, an air flow passage 24 a including a plurality of openings is formed inside the air electrode layer 13 so as to contact the inner surface of the air electrode layer 13.

In the embodiment II, in the cross section of the laminate of the fuel electrode layer 11, the solid electrolyte layer 12, and the air electrode layer 13, the contact edge of the fuel electrode layer 11 that contacts the surface of the solid electrolyte layer 12, in other words, the solid electrolyte layer The outer wall end surface of the fuel electrode layer 11 that reaches the surface of 12 surrounds the vicinity of the contact edge of the fuel electrode layer 11 and does not contact the contact edge of the isolation portion 21b that contacts the surface of the solid electrolyte layer 12. Thus, the fuel electrode layer 11 and the isolating portion 21b are formed so as not to coincide with each other, in other words, so as not to contact the inner wall end face of the isolating portion 21b reaching the surface of the solid electrolyte layer 12. . In this embodiment, in order to realize the configuration as described above, the contact edge or inner wall end surface of the isolation part 21b is separated from the contact edge or outer wall end surface of the fuel electrode layer 11, There is a gap 11 a between the contact edge or inner wall end surface of the isolation part 21 b and the contact edge or outer wall end surface of the fuel electrode layer 11. The gap 11a may be filled with a material different from that of the electrical insulator 21 forming the isolation part 21b. A material that shrinks when reduced, such as NiO, or a material that acts to press down the contact edge of the anode layer, such as dense Al ₂ O ₃ , is not suitable as a material to be filled. The material to be filled is preferably one that relieves stress without shrinking due to reduction, and examples of applicable materials include porous Al ₂ O ₃ .

Further, the contact edge or the outer wall end face of the fuel electrode layer 11 is not aligned with the contact edge of the air electrode layer 13 that contacts the surface of the solid electrolyte layer 12, in other words, the solid electrolyte. The fuel electrode layer 11 and the air electrode layer 13 are formed so as not to align with the outer wall end face of the air electrode layer 13 that reaches the surface of the layer 12 so as not to align. In this embodiment, in order to realize the configuration as described above, the contact edge or inner wall end surface of the isolation portion 21b is aligned or aligned with the contact edge or outer wall end surface of the air electrode layer 13. In addition, the isolation part 21b and the air electrode layer 13 are formed.

In the embodiment II configured as described above, it is possible to prevent the occurrence of cracks at the time of initial power generation at the contact edge of the fuel electrode layer 11 in contact with the surface of the solid electrolyte layer 12. I understood.

In addition, even if the fuel electrode layer 11 is formed so as to extend above the gap 11a as in the embodiment III shown in FIG. 4E, the same effects as those in the embodiment II described above can be obtained. It has been found by experiments of the present inventor that this can be achieved.

In Embodiments I to III of the solid electrolyte fuel cell module of the present invention, as shown in FIGS. 4C to 4E, the contact edge of the fuel electrode layer 11 that contacts the surface of the solid electrolyte layer 12 is used. However, it does not touch the contact edge of the isolation part 21b that covers the contact edge of the fuel electrode layer 11 and contacts the surface of the solid electrolyte layer 12. Further, the contact edge of the fuel electrode layer 11 is not aligned with the contact edge of the air electrode layer 13 that contacts the surface of the solid electrolyte layer 12. From these, even if the fuel electrode layer 11 exhibits the reduction contraction behavior by the hydrogen gas supplied to the fuel electrode layer 11 at the time of initial power generation, and stress is generated from the reduction contraction behavior, The contact edge of the isolation part 21 b does not work so as to press down the contact edge of the fuel electrode layer 11. Therefore, cracks resulting from the reduction shrinkage behavior during initial power generation can be prevented, and the cell is unlikely to be damaged during initial power generation.

In Embodiments I to III of the solid oxide fuel cell module of the present invention, as shown in FIGS. 4C to 4E, the fuel electrode layer 11 is interposed between the inter-cell separation portion 21a and the fuel electrode layer 11. A fuel gas flow passage 23a is formed so as to be in contact with the surface, and an air flow passage 24a is formed between the inter-cell separation portion 21a and the air electrode layer 13 so as to be in contact with the surface of the air electrode layer 13. It is preferable.

With this configuration, the fuel gas can be easily supplied to the surface of the fuel electrode layer 11 and the air can be easily supplied to the surface of the air electrode layer 13.

Further, Embodiment 1 of the solid oxide fuel cell according to the present invention includes a fuel gas supply path 23 for supplying fuel gas to each of the plurality of cells 10 as shown in FIGS. A gas supply path structure portion 21c having an air supply path 24 for supplying air to each of the cells, and the cell 10, the inter-cell separation portion 21a and the gas supply path structure portion 21c are formed by co-sintering. Is preferred.

With this configuration, the inter-cell separation portion 21a that functions as an interconnector and the gas supply path structure portion 21c that functions as a manifold can be integrally formed. As a result, the number of members can be reduced, and as a result, the number of manufacturing steps can be reduced.

In the first embodiment, even in the cross-sectional structure shown in FIG. 3, the contact edge of the fuel electrode layer 11 that contacts the surface of the solid electrolyte layer 12, in other words, the fuel electrode layer 11 that reaches the surface of the solid electrolyte layer 12. In other words, the outer wall end surface of the outer wall surrounds the vicinity of the contact edge of the fuel electrode layer 11 and does not coincide with the contact edge of the isolation portion 21b that contacts the surface of the solid electrolyte layer 12. The fuel electrode layer 11 and the isolation part 21b are formed so as not to coincide with each other so as not to contact the inner wall end face of the isolation part 21b reaching the surface of the solid electrolyte layer 12. In this embodiment, in order to realize the configuration as described above, the contact edge or inner wall end surface of the isolation part 21b is separated from the contact edge or outer wall end surface of the fuel electrode layer 11, There is a gap 11 a between the contact edge or inner wall end surface of the isolation part 21 b and the contact edge or outer wall end surface of the fuel electrode layer 11.

(Embodiment 2)
FIG. 5 shows a schematic configuration of a solid oxide fuel cell as Embodiment 2 of the present invention, and in particular, a plan view showing a planar arrangement of the fuel electrode layer 11, the solid electrolyte layer 12, and the air electrode layer 13. It is. FIG. 6 is a cross-sectional view showing a cross section seen from the direction along line VI-VI in FIG. 5 as a schematic configuration of a solid oxide fuel cell having a plurality of unit modules. FIG. 7 is a cross-sectional view showing a cross section seen from a direction along the line VII-VII in FIG. 5 as a schematic configuration of a solid oxide fuel cell having a plurality of unit modules. The solid oxide fuel cell 200 of the second embodiment is of a type in which fuel gas and air flow in opposite directions (counterflow type).

As shown in FIGS. 5 to 7, in the solid oxide fuel cell 200, the fuel gas supply path 23 is disposed so as to be in contact with part of both side surfaces of each fuel electrode layer 11 of the plurality of cells 10. Yes. The air supply path 24 is disposed so as to contact a part of both side surfaces of the air electrode layer 13 of each of the plurality of cells 10. The fuel gas is supplied through the fuel gas supply path 23, and the air is supplied through the air supply path 24. In FIG. 5, the fuel gas flows to the right from the fuel gas supply path 23 arranged on the left side, and flows to the left from the fuel gas supply path 23 arranged on the right side. On the other hand, in FIG. 5, air flows from the air supply path 24 arranged on the left side toward the right and flows from the air supply path 24 arranged on the right side toward the left.

Other configurations are the same as those of the solid oxide fuel cell 100 shown in FIGS. Further, FIG. 4 shows a cross-sectional view taken along the line IV-IV in FIG. 5 as a schematic configuration of a solid oxide fuel cell having a plurality of unit modules of a counter flow type solid oxide fuel cell. The cross section is the same.

Also in the second embodiment, the same operational effects as those of the first embodiment can be achieved.

In the second embodiment, even in the cross-sectional structures shown in FIGS. 6 and 7, the contact edge of the fuel electrode layer 11 that contacts the surface of the solid electrolyte layer 12, in other words, the fuel that reaches the surface of the solid electrolyte layer 12. The end face of the outer wall of the electrode layer 11 surrounds the vicinity of the contact edge of the fuel electrode layer 11 and does not coincide with the contact edge of the isolation portion 21 b that contacts the surface of the solid electrolyte layer 12. In other words, the fuel electrode layer 11 and the isolation part 21b are formed so as not to be in contact with each other so as not to contact the end face of the inner wall of the isolation part 21b reaching the surface of the solid electrolyte layer 12. In this embodiment, in order to realize the configuration as described above, the contact edge or inner wall end surface of the isolation part 21b is separated from the contact edge or outer wall end surface of the fuel electrode layer 11, There is a gap 11 a between the contact edge or inner wall end surface of the isolation part 21 b and the contact edge or outer wall end surface of the fuel electrode layer 11.

(Embodiment 3)
FIG. 8 shows a schematic configuration of a solid oxide fuel cell as Embodiment 3 of the present invention, and in particular, a plan view showing a planar arrangement of the fuel electrode layer 11, the solid electrolyte layer 12, and the air electrode layer 13. It is. FIG. 9 is a cross-sectional view showing a cross section seen from the direction along line IX-IX in FIG. 8 as a schematic configuration of a solid oxide fuel cell including a plurality of unit modules. FIG. 10 is a cross-sectional view showing a cross section of the unit module of the solid oxide fuel cell as viewed from the direction along the line XX in FIG. 8 as Embodiment 3 of the present invention. In FIG. 10, the electric conductor 22 is not shown.

As shown in FIGS. 8 to 10, in the solid oxide fuel cell 300, the gas supply path structure portion 21c is disposed so as to contact one side surface of each fuel electrode layer 11 of the plurality of cells 10. A fuel gas supply path 23 as an anode gas supply path for supplying fuel gas, and a cathode gas path for supplying air, arranged so as to be in contact with a side surface on one side of the air electrode layer 13. And an air supply path 24. In FIG. 8, the fuel gas flows from the fuel gas supply path 23 disposed on the left side toward the right, and the air flows downward from the air supply path 24 disposed on the upper side. As described above, the solid oxide fuel cell 300 according to the third embodiment is a type in which the flow of fuel gas and the flow of air are orthogonal (cross flow type).

Further, the cross section shown in FIG. 10 as a schematic configuration of the unit module of the cross flow type solid oxide fuel cell is similar to the cross section shown in FIG.

As shown in FIGS. 9 to 10, in the third embodiment of the present invention, in order to circulate the fuel gas from the fuel gas supply path 23 to the surface of the fuel electrode layer 11, the inter-cell separator 21a, the fuel electrode layer 11, A plurality of fuel gas flow passages 23 a are formed so as to be in contact with the surface of the fuel electrode layer 11. Specifically, in this embodiment, a fuel gas flow passage 23 a including a plurality of openings is formed in the fuel electrode layer 11 so as to be in contact with the inner surface of the fuel electrode layer 11.

Further, as shown in FIGS. 9 to 10, in order to distribute air from the air supply path 24 to the surface of the air electrode layer 13, the air electrode layer 13 is interposed between the inter-cell separation portion 21a and the air electrode layer 13. A plurality of air flow passages 24a are formed so as to contact the surface. Specifically, in this embodiment, an air flow passage 24 a including a plurality of openings is formed inside the air electrode layer 13 so as to contact the inner surface of the air electrode layer 13.

In Embodiment 3, in the cross section of the laminate of the fuel electrode layer 11, the solid electrolyte layer 12, and the air electrode layer 13 shown in FIG. 10, the contact edge of the fuel electrode layer 11 that contacts the surface of the solid electrolyte layer 12, In other words, the outer wall end face of the fuel electrode layer 11 that reaches the surface of the solid electrolyte layer 12 covers the contact edge of the fuel electrode layer 11 and contacts the contact edge of the isolation portion 21 b that contacts the surface of the solid electrolyte layer 12. The fuel electrode layer 11 and the isolating portion 21b are formed so as not to coincide with each other, so as not to coincide with each other, in other words, so as not to make contact with the inner wall end face of the isolating portion 21b reaching the surface of the solid electrolyte layer 12. Has been. In this embodiment, in order to realize the configuration as described above, the contact edge or inner wall end surface of the isolation part 21b is separated from the contact edge or outer wall end surface of the fuel electrode layer 11, There is a gap 11 a between the contact edge or inner wall end surface of the isolation part 21 b and the contact edge or outer wall end surface of the fuel electrode layer 11. The gap 11a may be filled with a material different from that of the electrical insulator 21 forming the isolation part 21b.

Further, the contact edge or the outer wall end face of the fuel electrode layer 11 is not aligned with the contact edge of the air electrode layer 13 that contacts the surface of the solid electrolyte layer 12, in other words, the solid electrolyte. The fuel electrode layer 11 and the air electrode layer 13 are formed so as not to align with the outer wall end face of the air electrode layer 13 that reaches the surface of the layer 12 so as not to align.

In the third embodiment configured as described above, it is possible to prevent the occurrence of cracks at the time of initial power generation at the contact edge of the fuel electrode layer 11 in contact with the surface of the solid electrolyte layer 12. I understood.

Other configurations are the same as those of the solid oxide fuel cell 100 shown in FIGS.

Also in the third embodiment, the same operational effects as those of the first embodiment can be achieved.

(Embodiment 4)
As Embodiment 4 of the present invention, in Embodiment 3 shown in FIGS. 8 to 10, the relationship between the first width y of the fuel gas flow passage 23a and the second width x of the air flow passage 24a is defined. The

FIG. 11 is a partial cross-sectional perspective view showing one cell constituting a unit module of a cross-flow type solid oxide fuel cell. FIG. 12 is a plan view showing the arrangement of the gas flow passages.

As shown in FIGS. 11 to 12, the cells constituting the unit module of the cross-flow type solid oxide fuel cell extend in the first direction so as to supply the fuel gas to the surface of the fuel electrode layer 11. A plurality of fuel gas flow passages 23a having a first width y arranged substantially in parallel and extending in a second direction intersecting the first direction for supplying air to the surface of the air electrode layer 13. And a plurality of air flow passages 24a having a second width x, which are arranged substantially parallel to each other. The cell and the side walls of the plurality of fuel gas flow passages 23a and the air flow passages 24a are formed by co-sintering. Assuming that the first width of the fuel gas flow passage 23a is y and the second width of the air flow passage 24a is x, x and y have a relationship of x ≧ 0.5 mm, y ≧ 0.5 mm, and x + 3y ≦ 8 mm. It is preferable to have.

With this configuration, in the solid electrolyte fuel cell 300 of a type in which the flow of fuel gas and the flow of air are orthogonal (cross flow type), the fuel electrode layer 11 constituting the cell is formed by the thermal contraction behavior during firing. Further, it is possible to suppress the amount of warpage generated in the laminate of the solid electrolyte layer 12 and the air electrode layer 13, and as a result, it is possible to suppress both the pressure loss in the fuel gas flow passage 23a and the air flow passage 24a.

In the solid oxide fuel cell manufacturing method according to the above-described first to third embodiments, the disappearing material that disappears by heating, for example, the carbon-containing material, and the material that forms the contact edge of the fuel electrode layer 11 are used. By filling between the materials forming the contact edge of the isolation part 21b and then co-sintering, the contact edge of the fuel electrode layer 11 and the contact edge of the isolation part 21b do not contact after sintering. For example, the fuel electrode layer 11 and the isolation part 21b are formed so that the gap 11a is formed as shown in FIGS. 4C to 4E and FIG.

By manufacturing in this way, the fuel electrode layer 11 and the isolation part 21b can be easily formed so that the contact edge of the fuel electrode layer 11 and the contact edge of the isolation part 21b do not contact each other.

Hereinafter, embodiments of the present invention will be described.

Example 1
First, the material powder of each member constituting the unit module of the parallel flow type solid oxide fuel cell shown in FIGS. 1 to 3 was prepared as follows.

Fuel electrode layer 11: Zirconia (ZrO ₂ ) 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% (Scandiaceria stabilized zirconia: ScCeSZ) A mixture with 40% by weight.

Solid electrolyte layer 12: zirconia (ZrO ₂ ) (scandiaceria stabilized zirconia: ScCeSZ) stabilized with scandia (Sc ₂ O ₃ ) with an addition amount of 10 mol% and ceria (CeO ₂ ) with an addition amount of 1 mol%.

Air electrode layer 13: stabilized with 60 wt% La _0.8 Sr _0.2 MnO ₃ , 10 mol% scandia (Sc ₂ O ₃ ) and 1 mol% ceria (CeO ₂ ) Mixture with 40% by weight of zirconia (ZrO ₂ ) (scandiaceria stabilized zirconia: ScCeSZ).

For the part 20a in the solid oxide fuel cell support structure 20 shown in FIG. 2, various raw material powders for preparing the following materials were prepared.

10% by weight of zircon (ZrSiO ₄ ) added to zirconia (ZrO ₂ ) (ceria stabilized zirconia: CeSZ) stabilized with 12 mol% of ceria (CeO ₂ ) (electrical insulating material).

Using the materials prepared as described above, first, as shown in FIG. 2, a green sheet was produced as follows for the portion 20a constituting the solid oxide fuel cell support structure 20.

For part 20a, various raw material powders, polyvinyl butyral binder, and a mixture of ethanol and toluene as an organic solvent (weight ratio is 1: 4) are mixed with solid electrolyte form by doctor blade method. A green sheet of the portion 20a of the fuel cell support structure 20 was produced.

In the green sheet of the portion 20a, through holes for forming a plurality of electric conductors 22 were formed in the electric insulator 21, as shown in FIGS.

Specifically, as shown in FIG. 13B, two types of through-holes are formed on the two sheets 25a and 25b so that the positions of the through-holes do not overlap, and these through-holes are formed. A conductive paste filling layer for forming the electric conductors 22a and 22b arranged at two kinds of positions was prepared by filling 50% by weight of silver and 50% by weight of palladium. On the surface of the sheet 25b on which the conductive paste filling layer for forming the electric conductor 22b is arranged so that the conductive paste filling layers for forming the electric conductors 22a and 22b are connected to each other, A paste having the same composition as described above was printed so as to be connected to the conductive paste filling layer arranged to form the electric conductor 22a on the sheet 25a. Thereafter, as shown in FIG. 13B, the two sheets 25a and 25b were laminated to produce a green sheet of the portion 20a.

As shown in FIG. 13A, as the green sheet of the portion 20a, a conductive paste filling layer for forming the electric conductors 22 of one kind of arrangement is formed on one sheet 25. Also good.

Further, in the portion 20a, an elongated through hole for forming the fuel gas supply passage 23 and the air supply passage 24 was formed as shown in FIGS. 2 to 3 by drilling with a mechanical puncher.

Next, with respect to the portion constituting the solid oxide fuel cell support structure 20 other than the portion 20a, various raw material powders, a polyvinyl butyral binder, and a mixture of ethanol and toluene as an organic solvent (mixing ratio by weight ratio) Was mixed with 1: 4), and then a green sheet of a portion of the solid oxide fuel cell support structure 20 was prepared by a doctor blade method.

In the portion of the green sheet constituting the solid oxide fuel cell support structure 20 other than the portion 20a, the fuel gas supply passage 23 and the air supply passage 24 shown in FIGS. A green sheet made of the electrical insulator 21 was produced so that the green sheets of the electrode layer 11 and the air electrode layer 13 could be fitted together. Further, the green sheet is drilled by a mechanical puncher to form a long and narrow through hole for forming a fuel gas supply path 23 and an air supply path 24 in the electrical insulator 21 as shown in FIGS. Formed.

Next, green sheets of the air electrode layer 13, the solid electrolyte layer 12, and the fuel electrode layer 11 shown in FIGS. 1 to 3 were produced as follows. Note that the combinations of the shapes of the air electrode layer 13, the solid electrolyte layer 12, and the fuel electrode layer 11 are four of Comparative Examples I and II, and Embodiments I and II, as shown in FIGS. Kinds were made.

After firing, 20 to 40 parts by weight of carbon powder was added to 100 parts by weight of each material powder of the fuel electrode layer 11 and the air electrode layer 13 so that pores necessary for gas diffusion were sufficiently formed. After mixing this mixed powder, a polyvinyl butyral binder, and a mixture of ethanol and toluene as an organic solvent (mixing ratio is 1: 4 by weight), the fuel electrode layer 11 and the air electrode are mixed by a doctor blade method. A green sheet of layer 13 was produced.

After mixing various raw material powders of the solid electrolyte layer 12, polyvinyl butyral binder, and a mixture of ethanol and toluene as an organic solvent (weight ratio is 1: 4), the solid electrolyte layer is obtained by a doctor blade method. Twelve green sheets were produced.

Specifically, green sheets of the fuel electrode layer 11, the solid electrolyte layer 12, and the air electrode layer 13 were produced in the shape shown in FIG. In the green sheet of the solid electrolyte layer 12, elongated through holes for forming the fuel gas supply passage 23 and the air supply passage 24 were formed as shown in FIG.

Further, in order to form the fuel electrode layer 11 having the shape shown in FIGS. 4B to 4D, a strip-shaped sheet made of carbon powder and a fuel are formed at the positions where the gap 11a and the fuel gas flow passage 23a are formed. The strip-shaped green sheets constituting the polar layer 11 were alternately arranged.

Furthermore, in order to form the air electrode layer 13 having the shape shown in FIGS. 4B and 4D, a strip-shaped sheet made of carbon powder and the air electrode layer 13 are formed at the location where the air flow passage 24a is formed. The strip-shaped green sheets to be placed are alternately sandwiched.

The width of the fuel gas flow passage 23a and the air flow passage 24a was 2 mm, the distance between the flow passages was 2 mm, the height was 0.15 mm, and the width of the gap 11a was 1 mm.

The green sheets of the solid oxide fuel cell support structure 20 produced as described above are laminated in order, and the green sheets of the air electrode layer 13, the solid electrolyte layer 12, and the fuel electrode layer 11 are further laminated thereon. 2 in order, the solid oxide fuel cell support structure 20 shown in FIG. 2 (the thickness of the inter-cell separation part 21a after firing: 100 μm) / the air electrode layer 13 (thickness after firing: 300 μm) / solid electrolyte 5 solid oxide fuel cell unit modules each having a layer 12 (thickness after firing: 50 μm) / fuel electrode layer 11 (thickness after firing: 300 μm) are stacked, and a gas passage is not formed at the top. The portion 20a of the electrolyte fuel cell support structure 20 was laminated. This laminate was pressure bonded by cold isostatic pressing (CIP) for 2 minutes at a pressure of 1000 kgf / cm ² and a temperature of 80 ° C. This pressure-bonded body was degreased at a temperature in the range of 400 to 500 ° C., and then fired by being held at a temperature in the range of 1300 to 1400 ° C. for 2 hours. As a result of the firing, the carbon powder disappeared, and the gap 11a, the fuel gas flow passage 23a, and the air flow passage 24a could be formed.

In this manner, a solid oxide fuel cell sample including the cross-sectional structures of Comparative Examples I and II and Embodiments I and II was produced.

As shown in FIG. 2, current collector plates 30 and 40 made of silver and having a thickness of 20 μm were fixed to the upper and lower surfaces of each sample of the solid oxide fuel cell produced as described above.

The open circuit voltage (OCV) of the fuel cell of each obtained sample was measured. Specifically, the fuel cell of each sample is heated to 800 ° C., hydrogen gas containing 5% water vapor and air are supplied through the fuel gas supply path 23 and the air supply path 24, respectively, and the air is supplied. The open circuit voltage when supplied at normal pressure (1 atm) was measured. Each sample was checked for cracks and gas leaks. Further, the pressure loss at a gas flow rate of 1.0 L / min was evaluated. If the pressure loss was 0.1 kgf / cm ² or less, it was determined that there was no problem in operation. Furthermore, the uniformity of gas flow rate was evaluated by simulation.

Table 1 shows the measurement results.

From Table 1, the open circuit voltage at normal pressure of Embodiments I and II is higher than that of Comparative Embodiments I and II. Therefore, by adopting the structure of the solid oxide fuel cell of the present invention, the seal as the whole battery is obtained. It can be seen that the property can be improved. From this, in the solid electrolyte fuel cell having the cross-sectional structure of Embodiments I and II, cracks caused by reduction shrinkage behavior at the time of initial power generation can be prevented. You can see that they are not. In Embodiment I and Comparative Embodiment I, since no gas flow passage is formed, the pressure loss is higher than in Embodiment II and Comparative Embodiment II. Further, in Embodiment I, there is a gap 11a between the contact edge or inner wall end surface of the isolation part 21b and the contact edge or outer wall end surface of the fuel electrode layer 11, so that it is compared with Comparative Example I. Therefore, fuel gas flows easily and pressure loss is small. On the other hand, in Embodiment I, there is no gap between the contact edge or inner wall end surface of the isolation part 21b and the contact edge or outer wall end surface of the fuel electrode layer 11 even though no gas flow passage is formed. Since 11a exists, the fuel gas flows through this gap, and the in-plane uniformity of the gas flow velocity is lower than that of the comparative form I.

(Example 2)
First, the material powder of each member constituting the unit module of the cross flow type solid oxide fuel cell shown in FIGS. 8 to 10 was prepared as follows.

Fuel electrode layer 11: Zirconia (ZrO ₂ ) 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% (Scandiaceria stabilized zirconia: ScCeSZ) A mixture with 40% by weight.

Solid electrolyte layer 12: zirconia (ZrO ₂ ) (scandiaceria stabilized zirconia: ScCeSZ) stabilized with scandia (Sc ₂ O ₃ ) with an addition amount of 10 mol% and ceria (CeO ₂ ) with an addition amount of 1 mol%.

Air electrode layer 13: stabilized with 60 wt% La _0.8 Sr _0.2 MnO ₃ , 10 mol% scandia (Sc ₂ O ₃ ) and 1 mol% ceria (CeO ₂ ) Mixture with 40% by weight of zirconia (ZrO ₂ ) (scandiaceria stabilized zirconia: ScCeSZ).

For the part 20a in the solid oxide fuel cell support structure 20 shown in FIG. 2, various raw material powders for preparing the following materials were prepared.

10% by weight of zircon (ZrSiO ₄ ) added to zirconia (ZrO ₂ ) (ceria stabilized zirconia: CeSZ) stabilized with 12 mol% of ceria (CeO ₂ ) (electrical insulating material).

Using the materials prepared as described above, first, as shown in FIG. 9, a green sheet was produced as follows for the portion 20a constituting the solid oxide fuel cell support structure 20.

For part 20a, various raw material powders, polyvinyl butyral binder, and a mixture of ethanol and toluene as an organic solvent (weight ratio is 1: 4) are mixed with solid electrolyte form by doctor blade method. A green sheet of the portion 20a of the fuel cell support structure 20 was produced.

In the green sheet of the portion 20a, through holes for forming a plurality of electrical conductors 22 were formed in the electrical insulator 21 as shown in FIG.

Specifically, as shown in FIG. 13B, two types of through-holes are formed on the two sheets 25a and 25b so that the positions of the through-holes do not overlap, and these through-holes are formed. A conductive paste filling layer for forming the electric conductors 22a and 22b arranged at two kinds of positions was prepared by filling 50% by weight of silver and 50% by weight of palladium. On the surface of the sheet 25b on which the conductive paste filling layer for forming the electric conductor 22b is arranged so that the conductive paste filling layers for forming the electric conductors 22a and 22b are connected to each other, A paste having the same composition as described above was printed so as to be connected to the conductive paste filling layer arranged to form the electric conductor 22a on the sheet 25a. Thereafter, as shown in FIG. 13B, the two sheets 25a and 25b were laminated to produce a green sheet of the portion 20a.

As shown in FIG. 13A, as the green sheet of the portion 20a, a conductive paste filling layer for forming the electric conductors 22 of one kind of arrangement is formed on one sheet 25. Also good.

Further, in the portion 20a, an elongated through hole for forming the fuel gas supply passage 23 and the air supply passage 24 was formed as shown in FIGS. 9 to 10 by drilling with a mechanical puncher.

Next, with respect to the portion constituting the solid oxide fuel cell support structure 20 other than the portion 20a, various raw material powders, a polyvinyl butyral binder, and a mixture of ethanol and toluene as an organic solvent (mixing ratio by weight ratio) Was mixed with 1: 4), and then a green sheet of a portion of the solid oxide fuel cell support structure 20 was prepared by a doctor blade method.

In the portion of the green sheet constituting the solid oxide fuel cell support structure 20 other than the portion 20a, the fuel gas supply passage 23 and the air supply passage 24 shown in FIGS. A green sheet made of the electrical insulator 21 was produced so that the green sheets of the electrode layer 11 and the air electrode layer 13 could be fitted together. Further, the green sheet is drilled by a mechanical puncher to form a long and narrow through hole for forming a fuel gas supply path 23 and an air supply path 24 in the electrical insulator 21 as shown in FIGS. Formed.

Next, green sheets of the air electrode layer 13, the solid electrolyte layer 12, and the fuel electrode layer 11 shown in FIGS. 8 to 10 were produced as follows.

After firing, 20 to 40 parts by weight of carbon powder was added to 100 parts by weight of each material powder of the fuel electrode layer 11 and the air electrode layer 13 so that pores necessary for gas diffusion were sufficiently formed. After mixing this mixed powder, a polyvinyl butyral binder, and a mixture of ethanol and toluene as an organic solvent (mixing ratio is 1: 4 by weight), the fuel electrode layer 11 and the air electrode are mixed by a doctor blade method. A green sheet of layer 13 was produced.

After mixing various raw material powders of the solid electrolyte layer 12, polyvinyl butyral binder, and a mixture of ethanol and toluene as an organic solvent (weight ratio is 1: 4), the solid electrolyte layer is obtained by a doctor blade method. Twelve green sheets were produced.

Specifically, green sheets of the fuel electrode layer 11, the solid electrolyte layer 12, and the air electrode layer 13 were produced in the shape shown in FIG. In the green sheet of the solid electrolyte layer 12, elongated through holes for forming the fuel gas supply path 23 and the air supply path 24 were formed as shown in FIG.

Further, in order to form the fuel electrode layer 11 having the shape shown in FIG. 10, a strip-like sheet made of carbon powder and a strip shape constituting the fuel electrode layer 11 are formed at the positions where the gap 11 a and the fuel gas flow passage 23 a are formed. The green sheets were alternately sandwiched.

Further, in order to form the air electrode layer 13 having the shape shown in FIG. 9, a strip-shaped sheet made of carbon powder and a strip-shaped green sheet constituting the air electrode layer 13 are formed at a position where the air flow passage 24 a is formed. Are placed alternately.

In addition, the height of the fuel gas flow passage 23a and the air flow passage 24a was 0.10 mm, the distance between the flow passages was 2 mm, and various widths were produced. The width of the gap 11a was 1 mm.

The green sheets of the solid oxide fuel cell support structure 20 produced as described above are laminated in order, and the green sheets of the air electrode layer 13, the solid electrolyte layer 12, and the fuel electrode layer 11 are further laminated thereon. 2 in order, the solid oxide fuel cell support structure 20 shown in FIG. 2 (thickness of the inter-cell separation part 21a after firing: 100 μm) / air electrode layer 13 (thickness after firing: 300 μm) / solid electrolyte 5 solid oxide fuel cell unit modules each having a layer 12 (thickness after firing: 50 μm) / fuel electrode layer 11 (thickness after firing: 300 μm) are stacked, and a gas passage is not formed at the top. The portion 20a of the electrolyte fuel cell support structure 20 was laminated. This laminate was pressure bonded by cold isostatic pressing (CIP) for 2 minutes at a pressure of 1000 kgf / cm ² and a temperature of 80 ° C. This pressure-bonded body was degreased at a temperature in the range of 400 to 500 ° C., and then fired by being held at a temperature in the range of 1300 to 1400 ° C. for 2 hours. As a result of the firing, the carbon powder disappeared, and the gap 11a, the fuel gas flow passage 23a, and the air flow passage 24a could be formed.

In this way, solid oxide fuel cell samples were produced in which the widths of the fuel gas flow passage 23a and the air flow passage 24a were variously changed.

Current collector plates 30 and 40 made of silver and having a thickness of 20 μm were fixed to the upper and lower surfaces of each sample of the solid oxide fuel cell produced as described above, as shown in FIG.

The obtained fuel cell of each sample was heated to 900 ° C., hydrogen gas containing 5% water vapor and air were supplied through the fuel gas supply path 23 and the air supply path 24, respectively, and the gas flow rate was 1 The pressure loss at 0.0 L / min was evaluated.

The measurement results of the pressure loss in the air flow passage 24a are shown in Table 2 and FIG.

From FIG. 14, assuming that the first width of the fuel gas flow passage 23a is y and the second width of the air flow passage 24a is x, x and y are x ≧ 0.5 mm, y ≧ 0.5 mm, and x + 3y ≦. In the sample having the relationship of 8 mm (the region where y ≦ −1 / 3 * x + 8/3 mm in FIG. 14), it can be seen that the pressure loss of the air flow passage 24a is 0.5 kgf / cm ² or less. On the other hand, in the sample (region of y> −1 / 3 * x + 8/3 mm in FIG. 14) where x and y have a relationship of x ≧ 0.5 mm, y ≧ 0.5 mm and x + 3y> 8 mm, the air flow path It can be seen that the pressure loss of 24a is 0.7 kgf / cm ² or more. In these samples, the laminated body of the fuel electrode layer 11, the solid electrolyte layer 12, and the air electrode layer 13 in the region where the fuel gas supply path 23 and the air supply path 24 intersect greatly warps toward the air electrode layer 13. Was observed. In any solid oxide fuel cell sample, the pressure loss in the fuel gas flow passage 23a was 0.1 kgf / cm ² or less.

From these results, when the first width y of the fuel gas flow passage 23a and the second width x of the air flow passage 24a satisfy x ≧ 0.5 mm, y ≧ 0.5 mm, and x + 3y ≦ 8 mm, The amount of warpage of the stacked body of the fuel electrode layer 11, the solid electrolyte layer 12, and the air electrode layer 13 in the region where the fuel gas supply path 23 and the air supply path 24 intersect can be greatly reduced. As a result, the fuel gas It turns out that it becomes possible to suppress both the pressure loss of the flow path 23a and the air flow path 24a.

(Example 3)
A solid electrolyte fuel in which the widths of the fuel gas flow passage 23a and the air flow passage 24a are variously changed in the same manner as in Example 2 except that the height of the fuel gas flow passage 23a and the air flow passage 24a is 0.15 mm. A battery sample was prepared.

The obtained fuel cell of each sample was heated to 900 ° C., hydrogen gas containing 5% water vapor and air were supplied through the fuel gas supply path 23 and the air supply path 24, respectively, and the gas flow rate was 1 The pressure loss at 0.0 L / min was evaluated.

FIG. 15 shows the measurement result of the pressure loss in the air flow passage 24a.

From FIG. 15, assuming that the first width of the fuel gas flow passage 23a is y and the second width of the air flow passage 24a is x, x and y are x ≧ 0.5 mm, y ≧ 0.5 mm, and x + 3y ≦. In the sample having the relationship of 8 mm (in the region of y ≦ −1 / 3 * x + 8/3 mm in FIG. 15), it can be seen that the pressure loss of the air flow passage 24a is 0.1 kgf / cm ² or less. On the other hand, in the sample in which x and y have a relationship of x ≧ 0.5 mm, y ≧ 0.5 mm, and x + 3y> 8 mm (y> −1 / 3 * x + 8/3 mm), the pressure loss of the air flow passage 24a is 0. It can be seen that it is 0.7 kgf / cm ² or more. In these samples, the laminated body of the fuel electrode layer 11, the solid electrolyte layer 12, and the air electrode layer 13 in the region where the fuel gas supply path 23 and the air supply path 24 intersect greatly warps toward the air electrode layer 13. Was observed. Further, the height of the fuel gas flow passage 23a and the air flow passage 24a was increased by 0.05 mm compared to the second embodiment, but x and y were x ≧ 0.5 mm, y ≧ 0.5 mm, and x + 3y> 8 mm. In the sample having the relationship (y> -1 / 3 * x + 8/3 mm in FIG. 15), the above-described warpage of the laminate cannot be suppressed, and the pressure loss of the air flow passage 24a can be reduced. I could not. In any solid oxide fuel cell sample, the pressure loss in the fuel gas flow passage 23a was 0.1 kgf / cm ² or less.

Note that FIG. 16 shows that among the samples prepared in Example 2, x and y are x ≧ 0.5 mm, y ≧ 0.5 mm, and x + 3y ≦ 8 mm (y ≦ −1 / 3 * x + 8/3 mm). It is a figure which shows the relationship between ratio of x / y and the pressure loss of the airflow path 24a about the sample which has a relationship. FIG. 16 shows that the pressure loss of the air flow passage 24a can be further reduced in the sample having the relationship of x / y ≧ 3/2 (the region where y ≦ 2/3 * x in FIG. 14).

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 scope and meaning equivalent to the scope of claims.

The solid electrolyte fuel cell according to the present invention eliminates the need for the seal member between the separator and the cell-manifold, which is necessary in the conventional solid oxide fuel cell, and therefore improves the sealing performance against gas as a whole battery. In addition to reducing the number of components, it is possible to prevent cracks arising from the reduction and shrinkage behavior during initial power generation, so that the cell is less likely to be damaged during initial power generation. An electrolyte fuel cell can be obtained.

Claims (6)

1. A cell composed of a laminate of an anode layer, a solid electrolyte layer, and a cathode layer, which are sequentially laminated;
   An isolator for isolating anode gas and cathode gas supplied to the cell from outside air;
   The cell and the isolation part are formed by co-sintering,
   The anode layer so that the contact edge of the anode layer that contacts the surface of the solid electrolyte layer and the contact edge of the isolation portion that contacts the surface of the solid electrolyte layer do not contact each other in the cross section of the laminate. And the isolation part is formed,
   The solid oxide fuel cell, wherein the anode layer and the cathode layer are formed such that the anode layer contact edge does not match the contact edge of the cathode layer that contacts the surface of the solid electrolyte layer.
2. The isolation unit includes an inter-cell separation unit disposed between the plurality of cells, and the inter-cell separation unit separates anode gas and cathode gas supplied to each of the plurality of cells from each other. The solid oxide fuel cell according to claim 1, wherein the solid oxide fuel cell is formed from a body and an electrical conductor formed in the electrical insulator and electrically connecting a plurality of cells to each other.
3. A gas supply path structure having an anode gas supply path for supplying an anode gas to each of the plurality of cells, and a cathode gas supply path for supplying a cathode gas to each of the plurality of cells;
   The solid oxide fuel cell according to claim 2, wherein the cell, the inter-cell separator and the gas supply path structure are formed by co-sintering.
4. An anode gas flow path is formed between the inter-cell separator and the anode layer so as to contact the surface of the anode layer, and between the inter-cell separator and the cathode layer, on the surface of the cathode layer. The solid oxide fuel cell according to claim 2 or 3, wherein a cathode gas flow passage is formed so as to be in contact with each other.
5. The anode gas flow passage is disposed to extend in a first direction to supply anode gas to a surface of the anode layer, and has a first width;
   The cathode gas flow passage is disposed to extend in a second direction intersecting the first direction to supply cathode gas to the surface of the cathode layer, and has a second width;
   The cell and the side walls of the anode gas flow path and the cathode gas flow path are formed by co-sintering,
   When the first width of the anode gas flow passage is y and the second width of the cathode gas flow passage is x, x and y are in a relationship of x ≧ 0.5 mm, y ≧ 0.5 mm, and x + 3y ≦ 8 mm. The solid oxide fuel cell according to claim 4, comprising:
6. A method for producing a solid oxide fuel cell according to any one of claims 1 to 5, comprising:
   The anode layer that has disappeared by heating is filled between the material that forms the anode layer contact edge and the material that forms the isolation contact edge, and then co-sintered, thereby the anode layer after sintering. A method for manufacturing a solid oxide fuel cell, wherein the anode layer and the isolation part are formed so that the contact edge and the isolation part contact edge do not contact each other.

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