JP6039459B2 - Solid oxide fuel cell - Google Patents

Description

  The present invention relates to a solid oxide fuel cell.

  Conventionally, a flat porous support substrate having a gas flow path formed therein, and a plurality of power generating element portions respectively provided at a plurality of locations separated from each other on the main surface of the flat support substrate, An electrical connection part that electrically connects one fuel electrode and the other air electrode of the matching power generation element part, and a bottom wall and a side wall closed in the circumferential direction at a plurality of locations on the main surface of the flat support substrate There are known solid oxide fuel cells in which first electrode recesses are formed, and in each of the first recesses, a fuel electrode current collector of a corresponding power generation element unit is embedded (for example, a patent) Reference 1).

  In Patent Document 1, a second recess is formed on the outer surface of the fuel electrode current collector, an electrical connection is embedded in the second recess, and a third electrode formed on the outer surface of the fuel electrode current collector. The fuel electrode active part is embedded in the recess, and the solid electrolyte formed on the surface of the fuel electrode active part extends to the surface of the electrical connection part. The solid electrolyte and the electrical connection part are connected to the fuel electrode side. Mixing of the supplied fuel gas and the air supplied to the air electrode side was prevented.

JP 2012-38718 A

  However, in Patent Document 1 described above, the solid electrolyte formed on the surface of the fuel electrode active portion extends to the surface of the electrical connection portion and is connected and gas-sealed. When trying to improve the power generation performance of the part, cracks etc. are likely to enter the thin solid electrolyte, the gas seal performance is lowered, and conversely, if the thickness of the solid electrolyte is increased to improve the gas seal performance, There was a problem that the power generation performance deteriorated.

  It is an object of the present invention to provide a solid oxide fuel cell that can improve power generation performance and gas sealing performance.

The solid oxide fuel cell of the present invention is provided in a flat porous support substrate having a gas flow path formed therein, and at a plurality of locations separated from each other on the main surface of the flat support substrate. A plurality of power generation element units each formed by laminating at least a fuel electrode, a solid electrolyte, and an air electrode and the adjacent power generation element units, and the fuel electrode of one power generation element unit and the other power generation unit An electrical connection portion that electrically connects the air electrode of the element portion, and a first recess having a bottom wall and a side wall closed in the circumferential direction at the plurality of locations on the main surface of the support substrate. respectively provided on respective first recess, the collector portion of the corresponding power generating element of the fuel electrode is embedded respectively, formed on the outer surface of the fuel electrode current collector embedded in the first recess 2 With respect to the fuel electrode current collector Ion the solid electrolyte on the upper surface of the content is often anode active portion of the material having conductivity is embedded is laminated, the second recess of the anode current collector embedded in the first recess is formed The electrical connection portion is embedded in a third recess formed on the outer surface at a position different from the position, and the outer surface of the support substrate includes an outer surface of the electrical connection portion and an outer surface of the solid electrolyte. A gas seal layer is provided so as to be spanned.

Further, the solid oxide fuel cell of the present invention includes a flat porous support substrate having a gas flow path formed therein, and a plurality of locations separated from each other on the main surface of the flat support substrate. Provided between each of the plurality of power generation element portions, each of which is formed by laminating at least a fuel electrode, a solid electrolyte, and an air electrode, and the adjacent power generation element portion, and the fuel electrode of one power generation element portion and the other An electrical connection portion that electrically connects the air electrode of the power generation element portion, and a first wall having a bottom wall and a side wall closed in the circumferential direction at the plurality of locations on the main surface of the support substrate. recesses are provided respectively on the respective first recess, is embedded collector portion of the corresponding power generating element of the fuel electrode, respectively, are formed on the outer surface of the fuel electrode current collector embedded in the first recess In the second recess, the fuel electrode current collector On the other hand, the outer surface of the fuel electrode active part with a high content ratio of the substance having ion conductivity is embedded, and the outer surface of the fuel electrode current collector embedded in the first recess is different from the position where the second recess is formed. The electrical connection portion is embedded in the third recess formed in the second recess, and the solid electrolyte is embedded in the fourth recess formed in the outer surface of the fuel electrode active portion embedded in the second recess. A gas seal layer is provided on the outer surface of the substrate so as to span the outer surface of the electrical connection portion and the outer surface of the solid electrolyte.

  In the solid oxide fuel cell according to the present invention, since the solid electrolyte is embedded in the second recess of the fuel electrode current collector or the fourth recess of the fuel electrode active part, the solid electrolyte can be formed thinly. The power generation performance of the element portion can be improved, and the outer surface of the support substrate, the outer surface of the solid electrolyte, and the outer surface of the electrical connection portion embedded in the fuel electrode current collector are made to have almost no steps. It is possible to improve the gas sealing performance of the gas sealing layer provided on the outer surface of the support substrate so as to span the outer surface of the electrical connection portion and the outer surface of the solid electrolyte.

(A) is a perspective view which shows a solid oxide fuel cell, (b) is a top view which shows the state by which the fuel electrode and the interconnector were embed | buried in the recessed part. (A) is sectional drawing corresponding to the 2-2 line of the solid oxide fuel cell shown in FIG. 1 (a), (b) is sectional drawing which shows a 1st recessed part and its vicinity. It is a figure for demonstrating the operating state of the solid oxide fuel cell shown in FIG. It is a perspective view which shows the support substrate shown in FIG. (A) is sectional drawing corresponding to the 7-7 line | wire of FIG. 4, (b) is sectional drawing which shows the state which formed each layer in the recessed part. (A) is sectional drawing which shows the state which embedded the solid electrolyte in the 4th recessed part of a fuel electrode active part, (b) is solid electrolyte so that the outer peripheral part of a solid electrolyte may protrude from the outer periphery of the active part of a fuel electrode. It is sectional drawing which shows the state laminated | stacked on the active part of the fuel electrode.

  FIG. 1A shows a solid oxide fuel cell (hereinafter also referred to as a cell) according to an embodiment of the present invention. This cell has a flat plate shape having a longitudinal direction (x-axis direction). A plurality of (four in this embodiment) identical power generation element portions A electrically connected in series to the upper and lower surfaces (main surfaces (planes) on both sides parallel to each other) of the support substrate 10 in the longitudinal direction 1 have a structure called a “horizontal stripe type” arranged at a predetermined interval.

The shape of the cell viewed from above is, for example, a rectangle having a side length of 5 to 50 cm in the longitudinal direction and a length in the width direction (y-axis direction) orthogonal to the longitudinal direction of 1 to 10 cm. The thickness of this cell is 1-5 mm. This cell has a vertically symmetrical shape with respect to a plane passing through the center in the thickness direction and parallel to the main surface of the support substrate 10. Hereinafter, in addition to FIG. 1A, details of this cell will be described with reference to FIG. 2A which is a partial sectional view corresponding to line 2-2 shown in FIG. 1A of this cell. . FIG. 2A is a partial cross-sectional view showing a configuration (part of) each of a typical pair of adjacent power generation element portions A and A and a configuration between the power generation element portions A and A. The configuration between the other power generation element portions A and A of the other sets is the same as the configuration shown in FIG.

  The support substrate 10 is a flat plate-like fired body made of a porous material having no electron conductivity (insulating). Inside the support substrate 10, a plurality (six in this embodiment) of fuel gas passages 11 (through holes) extending in the longitudinal direction are formed at predetermined intervals in the width direction. In the present embodiment, first recesses 12 are formed at a plurality of locations on the main surface of the support substrate 10, and each first recess 12 extends over the entire circumference of the bottom wall made of the material of the support substrate 10. It is a rectangular parallelepiped depression defined by circumferentially closed side walls (two side walls along the longitudinal direction and two side walls along the width direction) made of the material of the support substrate 10.

  The support substrate 10 may be configured to include “transition metal oxide or transition metal” and insulating ceramics. As the “transition metal oxide or transition metal”, NiO (nickel oxide) or Ni (nickel) is suitable. The transition metal can function as a catalyst for promoting a reforming reaction of the fuel gas (hydrocarbon-based gas reforming catalyst).

Further, as the insulating ceramic, MgO (magnesium oxide) or “mixture of MgAl ₂ O ₄ (magnesia alumina spinel) and MgO (magnesium oxide)” is preferable. Further, CSZ (calcia stabilized zirconia), YSZ (8YSZ) (yttria stabilized zirconia), Y ₂ O ₃ (yttria) may be used as the insulating ceramic.

  As described above, since the support substrate 10 contains “transition metal oxide or transition metal”, the gas containing the residual gas component before the reforming is supplied to the fuel through the numerous pores inside the porous support substrate 10. In the process of being supplied from the gas flow path 11 to the fuel electrode, the catalytic action can promote the reforming of the residual gas component before the reforming. In addition, the insulating property of the support substrate 10 can be ensured by the support substrate 10 containing insulating ceramics. As a result, insulation between adjacent fuel electrodes can be ensured.

  The thickness of the support substrate 10 is 1 to 5 mm. Hereinafter, only the configuration on the upper surface side of the support substrate 10 will be described in consideration of the fact that the shape of the structure is vertically symmetrical. The same applies to the configuration of the lower surface side of the support substrate 10.

  As shown in FIG. 2, the entire fuel electrode current collector 21 is embedded (filled) in each first recess 12 formed in the upper surface (upper main surface) of the support substrate 10. Therefore, each fuel electrode current collector 21 has a rectangular parallelepiped shape. A second recess 21 a is formed on the upper surface (outer surface) of each fuel electrode current collector 21. As shown in FIG. 1B, each of the second recesses 21a has a bottom wall made of the material of the fuel electrode current collector 21, a side wall closed in the circumferential direction (two side walls along the longitudinal direction, and a width direction). A rectangular parallelepiped depression defined by two side walls). Of the side walls closed in the circumferential direction, two side walls along the longitudinal direction are made of the material of the support substrate 10, and two side walls along the width direction are made of the material of the fuel electrode current collector 21.

  Each of the second recesses 21 a is filled (filled) with the entire fuel electrode active portion 22, and further filled (filled) with the entire solid electrolyte 41, and the solid electrolyte 41 is laminated on the upper surface of the fuel electrode active portion 22. Yes. Therefore, each fuel electrode active part 22 and the solid electrolyte 41 have a rectangular parallelepiped shape. A fuel electrode 20 is configured by the fuel electrode current collector 21 and the fuel electrode active unit 22. The fuel electrode 20 (fuel electrode current collector 21 + fuel electrode active part 22) is a fired body made of a porous material having electron conductivity. Two side surfaces along the width direction of each anode active portion 22 and solid electrolyte 41 are in contact with the anode current collector 21 in the second recess 21a.

  A third recess 21b is formed in the upper surface (outer surface) of each fuel electrode current collector 21 except for the second recess 21a. Each of the third recesses 21b is defined by a bottom wall made of the material of the anode current collector 21 and side walls closed in the circumferential direction (two side walls along the longitudinal direction and two side walls along the width direction). It is a rectangular parallelepiped depression. Of the side walls closed in the circumferential direction, two side walls along the longitudinal direction are made of the material of the support substrate 10, and two side walls along the width direction are made of the material of the fuel electrode current collector 21. In FIG. 1B, the solid electrolyte 41 is laminated on the anode active portion 22 in the second recess 21a.

  An interconnector 30 is embedded (filled) in each third recess 21b. Accordingly, each interconnector 30 has a rectangular parallelepiped shape. The interconnector 30 is a fired body made of a dense material having electronic conductivity. The two side surfaces and the bottom surface along the width direction of each interconnector 30 are in contact with the fuel electrode current collector 21 in the recess 21b.

  One upper surface (outer surface) of the solid electrolyte 41, upper surface (outer surface) of the interconnector 30, and main surface of the support substrate 10, one flat surface (main surface of the support substrate 10 when the recess 12 is not formed) The same plane). That is, no step is formed between the upper surface of the solid electrolyte 41, the upper surface of the interconnector 30, and the main surface of the support substrate 10.

The fuel electrode active part 22 may be composed of, for example, NiO (nickel oxide) and YSZ (yttria stabilized zirconia). Or you may be comprised from NiO (nickel oxide) and GDC (gadolinium dope ceria). The fuel electrode current collector 21 can be composed of, for example, NiO (nickel oxide) and YSZ (yttria stabilized zirconia). Alternatively, it may be composed of NiO (nickel oxide) and Y ₂ O ₃ (yttria), or may be composed of NiO (nickel oxide) and CSZ (calcia stabilized zirconia). The thickness of the anode active portion 22 is 5 to 30 μm, and the thickness of the anode current collecting portion 21 (that is, the depth of the first recess 12) is 50 to 500 μm.

  As described above, the fuel electrode current collector 21 includes a substance having electronic conductivity. The fuel electrode active part 22 includes a substance having electron conductivity and a substance having oxidative ion (oxygen ion) conductivity. The “volume ratio of the substance having oxidative ion conductivity relative to the total volume excluding the pore portion” in the anode active portion 22 is “the oxidative ion conductivity relative to the entire volume excluding the pore portion” in the anode current collecting portion 21. Greater than the volume fraction of the substance having

The interconnector 30 can be composed of, for example, LaCrO ₃ (lanthanum chromite). Alternatively, it may be composed of (Sr, La) TiO ₃ (strontium titanate). The thickness of the interconnector 30 is 10 to 100 μm.

  On the outer peripheral surface extending in the longitudinal direction of the support substrate 10 in a state where the fuel electrode 20 is embedded in each of the first recesses 12, the central portion in the longitudinal direction of each portion where the plurality of interconnectors 30 are formed, and the solid electrolyte 41 The entire surface excluding the central portion in the longitudinal direction is covered with a gas seal layer 40. The solid electrolyte 41 is a fired body made of a dense material having ionic conductivity and no electronic conductivity. The solid electrolyte 41 can be composed of, for example, YSZ (yttria stabilized zirconia). Or you may comprise from LSGM (lantern gallate). The thickness of the solid electrolyte 41 is 3 to 50 μm.

The gas seal layer 40 is a fired body made of an electrically insulating dense material. For example, the gas seal layer 40 is mainly made of insulating ceramics, and MgO (magnesium oxide) and MgAl ₂ O ₄ (magnesia spinel) are suitable. Also, CSZ, 3YSZ, Y ₂ O ₃ (yttria), TiO ₂ or the like may be used. The thickness is desirably 20 to 100 μm,
It is formed thicker than the thickness of the solid electrolyte 41.

  That is, the entire outer peripheral surface extending in the longitudinal direction of the support substrate 10 in a state where the fuel electrode 20 is embedded in each recess is covered with a dense layer composed of the interconnector 30, the solid electrolyte 41, and the gas seal layer 40. It has been broken. This dense layer exhibits a gas sealing function that prevents mixing of the fuel gas flowing in the space inside the dense layer and the air flowing in the space outside the dense layer.

  As shown in FIG. 2, in this embodiment, the gas seal layer 40 includes both longitudinal end portions on the upper surface of the solid electrolyte 41, both longitudinal end portions on the upper surface of the interconnector 30, and the support substrate 10. Covers the main surface. Here, as described above, no step is formed between the upper surface of the solid electrolyte 41, the upper surface of the interconnector 30, and the main surface of the support substrate 10. Therefore, the gas seal layer 40 is flattened. As a result, compared with the case where a step is formed in the gas seal layer 40, the generation of cracks in the gas seal layer 40 due to stress concentration can be suppressed, and the gas seal function of the gas seal layer 40 can be reduced. Can be suppressed.

  Further, since the gas seal layer 40 is provided separately from the solid electrolyte 41, the thickness of the solid electrolyte 41 and the gas seal layer 40 can be controlled separately, and the thickness of the solid electrolyte 41 is reduced, and the gas seal layer 40 is reduced. As a result, the power generation performance can be improved and the gas sealing performance by the gas sealing layer 40 can be improved.

  An air electrode 60 is formed on the upper surface of the solid electrolyte 41 through a reaction preventing film 50. The reaction preventing film 50 is a fired body made of a dense material, and the air electrode 60 is a fired body made of a porous material having electron conductivity. The shape of the reaction preventing film 50 and the air electrode 60 viewed from above is substantially the same rectangle as the fuel electrode active part 22.

The reaction preventing film 50 can be made of, for example, GDC = (Ce, Gd) O ₂ (gadolinium-doped ceria). The thickness of the reaction preventing film 50 is 3 to 50 μm. The air electrode 60 can be made of, for example, LSCF = (La, Sr) (Co, Fe) O ₃ (lanthanum strontium cobalt ferrite). Alternatively, from LSF = (La, Sr) FeO ₃ (lanthanum strontium ferrite), LNF = La (Ni, Fe) O ₃ (lanthanum nickel ferrite), LSC = (La, Sr) CoO ₃ (lanthanum strontium cobaltite), etc. It may be configured. Further, the air electrode 60 may be configured by two layers of a first layer (inner layer) made of LSCF and a second layer (outer layer) made of LSC. The thickness of the air electrode 60 is 10 to 100 μm.

  The reaction preventing film 50 is interposed because the YSZ in the solid electrolyte 41 reacts with the Sr in the air electrode 60 in the cell at the time of manufacturing the cell or in operation, and the solid electrolyte 41 and the air electrode 60 This is to suppress the occurrence of a phenomenon in which a reaction layer having a large electric resistance is formed at the interface.

  Here, the laminated body formed by laminating the fuel electrode 20, the solid electrolyte 41, the reaction preventing film 50, and the air electrode 60 corresponds to the “power generation element portion A” (see FIG. 2). That is, on the upper surface of the support substrate 10, a plurality (four in this embodiment) of power generation element portions A are arranged at predetermined intervals in the longitudinal direction.

  Regarding the adjacent power generation element portions A and A, the air electrode 60 of the other power generation element portion A (on the left side in FIG. 2A) and one power generation element portion A (on the right side in FIG. 2A). An air electrode current collecting film 70 is formed on the air electrode 60, the gas seal layer 40, and the upper surface of the interconnector 30 so as to straddle the interconnector 30. The air electrode current collector film 70 is a fired body made of a porous material having electron conductivity. The shape of the air electrode current collector film 70 as viewed from above is a rectangle.

The air electrode current collector film 70 can be made of, for example, LSCF = (La, Sr) (Co, Fe) O ₃ (lanthanum strontium cobalt ferrite). Alternatively, it may be composed of LSC = (La, Sr) CoO ₃ (lanthanum strontium cobaltite). Or you may comprise from Ag (silver) and Ag-Pd (silver palladium alloy). The thickness of the air electrode current collector film 70 is 50 to 500 μm.

  By forming each air electrode current collecting film 70 in this way, the air electrode 60 of the other power generation element part A (on the left side in FIG. 2A) for the adjacent power generation element parts A and A, One (on the right side in FIG. 2 (a)) the fuel electrode 20 (particularly the fuel electrode current collector 21) of the power generating element part A is electronically conductive. ”Is electrically connected.

  As a result, a plurality (four in this embodiment) of power generating element portions A arranged on the upper surface of the support substrate 10 are electrically connected in series. Here, “air electrode current collector film 70 and interconnector 30” having electronic conductivity corresponds to “electrical connection portion”.

  The interconnector 30 corresponds to the “first portion made of a dense material” in the “electrical connection portion”, and has a porosity of 10% or less. The air electrode current-collecting film 70 corresponds to the “second portion made of a porous material” in the “electrical connection portion”, and has a porosity of 20 to 60%.

  As described above, as shown in FIG. 3, the fuel gas (hydrogen gas or the like) flows through the fuel gas passage 11 of the support substrate 10 and the upper and lower surfaces of the support substrate 10 ( In particular, by exposing each air electrode current collector film 70) to “gas containing oxygen” (air or the like) (or flowing a gas containing oxygen along the upper and lower surfaces of the support substrate 10), both sides of the solid electrolyte 41 are provided. An electromotive force is generated by an oxygen partial pressure difference generated between the surfaces. Furthermore, when this structure is connected to an external load, chemical reactions shown in the following formulas (1) and (2) occur, and current flows (power generation state).

(1/2) · O ₂ + 2e ⁻ → O ²⁻ (where: air electrode 60) (1)
H ₂ + O ²⁻ → H ₂ O + 2e ⁻
(At: Fuel electrode 20) (2)
In the power generation state, as shown in FIG. 2A, the current flows as indicated by the arrows in the adjacent power generation element portions A and A. As a result, electric power is extracted from the entire cell (specifically, via the interconnector 30 of the power generating element portion A on the frontmost side and the air electrode 60 of the power generating element portion A on the farthest side in FIG. 3).

(Production method)
Next, an example of a manufacturing method of the “horizontal stripe type” cell shown in FIG. 1 will be briefly described with reference to FIGS. 4 to 5, “g” at the end of the reference numeral of each member indicates that the member is “before firing”.

First, a support substrate molded body 10g having the shape shown in FIG. 4 is prepared. This support substrate molded body 10g uses, for example, a method such as extrusion molding or cutting using a slurry obtained by adding a binder or the like to the powder of the material of the support substrate 10 (for example, NiO + MgO + MgAl ₂ O ₄ ). To make.

Next, as shown in FIG. 5, a molded body 21 g of the fuel electrode current collector is embedded and formed in each first recess. Next, a molded body 22g of the fuel electrode active part and a molded film 41g of the solid electrolyte 41 are embedded and formed in each second recess formed on the outer surface of the molded body 21g of each fuel electrode current collector. The molded body 21g of each fuel electrode current collector and the molded body 22g of each fuel electrode active part are obtained, for example, by adding a binder or the like to the powder of the material of the fuel electrode 20 (for example, Ni and YSZ). The slurry is embedded and formed using a printing method or the like.

  The solid electrolyte molding film 41g is formed by using a slurry obtained by adding a binder or the like to a powder of the material of the solid electrolyte 41 (for example, YSZ), using a printing method, a dipping method, or the like.

Subsequently, each third electrode formed on the outer surface of the molded body 21g of each fuel electrode current collector section “excluding the section where the molded body 22g of the fuel electrode active section and the solid electrolyte molded film 41g are embedded”. The interconnector molded bodies 30g are respectively embedded and formed in the recesses. The molded body 30g of each interconnector is embedded and formed using a slurry obtained by adding a binder or the like to the material of the interconnector 30 (for example, LaCrO ₃ ) using a printing method or the like.

  Next, the outer circumference extending in the longitudinal direction of the molded body 10g of the support substrate in a state where the molded body of the plurality of fuel electrodes (21g + 22g), the molded film 41g of the solid electrolyte, and the molded body 30g of the plurality of interconnectors are respectively embedded and formed. On the surface, a molded film of the gas seal layer is formed on the entire surface excluding the central portion in the longitudinal direction of each portion where the plurality of interconnector molded bodies 30g are formed and the central portion in the longitudinal direction of the solid electrolyte molded body 41g. .

The molded film of the gas seal layer is obtained by using a slurry obtained by adding a binder or the like to the powder of the material of the gas seal layer 40 (for example, NiO + MgO + MgAl ₂ O ₄ ), using a printing method, a dipping method, or the like. Form.

  Next, a molded film of a reaction preventing film is formed on the outer surface of the solid electrolyte molded body 41g. The molded film of each reaction prevention film is formed using a slurry obtained by adding a binder or the like to the powder of the material of the reaction prevention film 50 (for example, GDC), using a printing method or the like.

  Then, 10 g of the support substrate molded body in which various molded films are thus formed is fired at 1500 ° C. for 3 hours in air, for example. Thereby, the structure in a state where the air electrode 60 and the air electrode current collector film 70 are not formed in the cell shown in FIG. 1 is obtained.

  Next, an air electrode forming film is formed on the outer surface of each reaction preventing film 50. The molded film of each air electrode is formed using a slurry obtained by adding a binder or the like to the powder of the material of the air electrode 60 (for example, LSCF) using a printing method or the like.

  Next, with respect to the adjacent power generation element part A, the molded film of the air electrode current collector film so as to straddle the molding film of the air electrode 60 of the other power generation element part A and the interconnector 30 of the one power generation element part A. Form. The molded film of each air electrode current collector film is formed using a slurry obtained by adding a binder or the like to the powder of the material of the air electrode current collector film 70 (for example, LSCF), using a printing method or the like. To do.

  And the support substrate 10 in the state in which the molded film is formed in this way is baked, for example, in air at 1050 ° C. for 3 hours. As a result, the cell shown in FIG. 1 is obtained.

(Action / Effect)
In the cell of the above form, the gas seal layer 40 covers both longitudinal end portions of the outer surface of the solid electrolyte 41, both longitudinal end portions of the outer surface of the interconnector 30, and the main surface of the support substrate 10. Yes. Here, no step is formed between the outer surface of the solid electrolyte 41, the outer surface of the interconnector 30, and the main surface of the support substrate 10. Therefore, the gas seal layer 40 is flattened. As a result, compared with the case where a step is formed in the gas seal layer 40, the generation of cracks in the gas seal layer 40 due to stress concentration can be suppressed, and the gas seal function of the gas seal layer 40 can be reduced. Can be suppressed. Furthermore, since the gas seal layer 40 is provided separately from the solid electrolyte 41, the thickness of the solid electrolyte 41 can be reduced, and at the same time the thickness of the gas seal layer 40 can be increased, and the power generation performance can be improved and the gas seal performance can be improved. Can be improved.

  Further, each of the plurality of first recesses 12 embedded in the upper and lower surfaces of the support substrate 10 for embedding the fuel electrode 20 (fuel electrode current collector 21) is made of the material of the support substrate 10 over the entire circumference. It has a side wall closed in the circumferential direction. In other words, a frame surrounding each first recess 12 is formed on the support substrate 10. Therefore, this structure is not easily deformed when the support substrate 10 receives an external force.

  Further, the support substrate 10 and the embedded structure are filled and embedded in the respective recesses of the support substrate 10 such as the fuel electrode 20 (the fuel electrode current collector 21 + the fuel electrode active part 22) and the interconnector 30 without any gaps. The formed member is co-sintered. Therefore, a sintered body having high bondability between members and high reliability can be obtained.

  Further, in the above-described embodiment, a plurality of power generation element portions A are provided on each of the upper and lower surfaces of the flat support substrate 10. Thereby, compared with the case where a plurality of power generation element portions are provided only on one side surface of the support substrate, the number of power generation element portions in the structure can be increased, and the power generation output of the fuel cell can be increased.

  In addition, this invention is not limited to the said embodiment, A various modification can be employ | adopted within the scope of the present invention. For example, in the above embodiment, as shown in FIG. 4 and the like, the planar shape of the first recess 12 formed in the support substrate 10 (the shape when viewed from the direction perpendicular to the main surface of the support substrate 10) is rectangular. However, it may be, for example, a square, a circle, an ellipse, or a long hole shape.

  Further, in the above embodiment, a plurality of first recesses 12 are formed on each of the upper and lower surfaces of the flat support substrate 10 and a plurality of power generating element portions A are provided, but only one side of the support substrate 10 is provided. A plurality of first recesses 12 may be formed and a plurality of power generation element portions A may be provided.

  Further, in the above embodiment, the fuel electrode current collector 21 and the solid electrolyte 41 are embedded in the second recess 21a. However, the fuel electrode current collector 21, the solid electrolyte 41, and the reaction preventing layer 50 are embedded in the second recess 21a. You may do it. In this case, the gas seal layer 40 is further flattened, and the gas seal performance of the gas seal layer 40 can be improved.

  FIG. 6A shows another embodiment. In this embodiment, the solid electrolyte 41 is embedded in the fourth recess 45 formed on the outer surface of the anode active portion 22 embedded in the second recess 21a. A gas seal layer 40 is provided on the outer surface of the support substrate 10 so as to span the partial outer surface of the interconnector 30 and the partial outer surface of the solid electrolyte 41.

  In such a cell, since the fuel electrode active part 22 covers the lower surface and the side surface of the solid electrolyte 41, the power generation area increases and the power generation performance can be improved. Also in this case, it goes without saying that the solid electrolyte 41 and the reaction preventing layer 50 may be embedded in the fourth recess 45.

FIG. 6B shows still another embodiment. In this embodiment, the second recess 21a is composed of a recess 21a1 for the fuel electrode active portion and a recess 21a2 for the solid electrolyte. When viewed, the solid electrolyte recess 21a2 is formed larger than the area of the fuel electrode active portion recess 21a1, and the fuel electrode active portion 22 and the solid electrolyte 41 are embedded in the respective recesses 21a1 and 21a2. The solid electrolyte 41 is laminated on the fuel electrode active part 22 so that the outer peripheral part of the solid electrolyte 41 protrudes from the outer periphery of the fuel electrode active part 22.

  In such a cell, the interface between the fuel electrode active part 22 and the fuel electrode current collector 21 and the interface between the solid electrolyte 41 and the fuel electrode current collector 21 do not overlap with each other, thereby preventing the occurrence of interface peeling due to firing shrinkage or the like. In addition, since the interface sealed by the gas seal layer 40 does not increase, the gas sealability can be improved, and the fuel utilization rate and the like can be improved.

DESCRIPTION OF SYMBOLS 10 ... Support substrate 11 ... Fuel gas flow path 12 ... 1st recessed part 20 ... Fuel electrode 21 ... Fuel electrode current collection part 21a ... 2nd recessed part 21b ... 3rd recessed part 22 ... Fuel electrode active part 30 ... Interconnector 40 ... Gas seal layer 41 ... Solid electrolyte 45 ... Fourth recess A ... Power generation element

Claims (4)

A flat porous support substrate having a gas flow path formed therein;
A plurality of power generating element portions each provided at a plurality of locations separated from each other on the main surface of the flat support substrate, and at least a fuel electrode, a solid electrolyte, and an air electrode;
Each provided between the adjacent power generation element parts, and having an electrical connection part for electrically connecting the fuel electrode of one of the power generation element parts and the air electrode of the other power generation element part,
A first recess having a bottom wall and a side wall closed in the circumferential direction is provided at each of the plurality of locations on the main surface of the support substrate, and the fuel electrode of the power generation element unit corresponding to each first recess is provided. Current collectors are buried,
In the second recess formed on the outer surface of the anode current collector embedded in the first recess, the anode active portion having a high content ratio of a substance having ion conductivity with respect to the anode current collector . The solid electrolyte is laminated and embedded on the upper surface ,
The electrical connection portion is embedded in a third recess formed on the outer surface of the fuel electrode current collector embedded in the first recess at a position different from the position where the second recess is formed,
A solid oxide fuel cell, wherein a gas seal layer is provided on an outer surface of the support substrate so as to span between an outer surface of the electrical connection portion and an outer surface of the solid electrolyte. 2. The solid oxide fuel cell according to claim 1, wherein the solid electrolyte is stacked on the fuel electrode active part such that the outer peripheral part of the solid electrolyte protrudes from the outer periphery of the fuel electrode active part. 3. cell. A flat porous support substrate having a gas flow path formed therein;
A plurality of power generating element portions each provided at a plurality of locations separated from each other on the main surface of the flat support substrate, and at least a fuel electrode, a solid electrolyte, and an air electrode;
Each provided between the adjacent power generation element parts, and having an electrical connection part for electrically connecting the fuel electrode of one of the power generation element parts and the air electrode of the other power generation element part,
A first recess having a bottom wall and a side wall closed in the circumferential direction is provided at each of the plurality of locations on the main surface of the support substrate, and the fuel electrode of the power generation element unit corresponding to each first recess is provided. Current collectors are buried,
In the second recess formed on the outer surface of the fuel electrode current collector embedded in the first recess, a fuel electrode active part having a high content ratio of a substance having ion conductivity with respect to the fuel electrode current collector is provided. Buried,
The electrical connection portion is embedded in a third recess formed on the outer surface of the fuel electrode current collector embedded in the first recess at a position different from the position where the second recess is formed,
The solid electrolyte is embedded in a fourth recess formed on the outer surface of the fuel electrode active portion embedded in the second recess;
A solid oxide fuel cell, wherein a gas seal layer is provided on an outer surface of the support substrate so as to span between an outer surface of the electrical connection portion and an outer surface of the solid electrolyte. The solid oxide fuel cell according to any one of claims 1 to 3, wherein the gas seal layer is thicker than a thickness of the solid electrolyte.