JP6039463B2 - 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 according to the present invention includes a flat plate-like 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 plate-like support substrate. Provided between the plurality of power generation element portions in which at least the fuel electrode, the solid electrolyte, the intermediate film, and the air electrode are laminated, and the adjacent power generation element portion, and the fuel of one of the power generation element portions A plurality of electrical connection portions that electrically connect the electrode and the air electrode of the other power generation element portion, and the intermediate film is a dense body made of a ceria-based material having electrical conductivity , 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 current collector of the power generation element unit corresponding to each first recess is provided. Each part is buried, the first In the second recess formed in the outer surface of the fuel electrode current collector embedded in the part, a fuel electrode active part with a large content ratio of a substance having ion conductivity with respect to the fuel electrode current collector is embedded, Conductivity that constitutes a part of the electrical connection portion in the 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 conductive dense body is embedded, and the solid electrolyte laminated on the fuel electrode active portion is extended from both sides of the one and the other power generation element portions, and the conductive dense body is arranged in the arrangement direction of the power generation elements. laminated on both ends, both ends of the arrangement direction of the middle ligament Furthermore, characterized in that located above the conductive dense material through the solid electrolyte.

  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. A plurality of power generation element portions each provided in an array, each including at least a fuel electrode, a solid electrolyte, an intermediate film, and an air electrode, and each of the power generation element portions provided between the adjacent power generation element portions. And an electrical connection part for electrically connecting the air electrode of the other power generation element part, and the intermediate film is a dense body made of a ceria-based material, and the main surface of the support substrate Are provided with first recesses each having a bottom wall and a side wall closed in the circumferential direction, and corresponding fuel electrode current collectors of the power generation element unit are embedded in the first recesses, respectively. , The fuel embedded in the first recess In the second recess formed on the outer surface of the electrode current collector, a fuel electrode active part having a high content of a substance having ion conductivity with respect to the fuel electrode current collector is embedded, and embedded in the first recess. A conductive dense body constituting a part of the electrical connection portion is embedded in a third recess formed on an outer surface of the fuel electrode current collector that is different from the position where the second recess is formed. A dense sealing layer having an insulating property is disposed between the conductive dense body and the side wall of the third recess, and the solid electrolyte laminated on the fuel electrode active portion is formed between the one and the other. Extending from both sides of the power generation element portion and stacked on both ends of the seal layer in the arrangement direction of the power generation elements, and further, the end of the intermediate film in the arrangement direction is positioned above the seal layer The interlayer film is laminated on the solid electrolyte. .

  The solid oxide fuel cell according to the present invention forms a gas barrier layer with a conductive dense body, or a conductive dense body and a sealing layer, and a solid electrolyte / interlayer laminate. Even if the thickness is reduced, the gas barrier effect can be improved by laminating the intermediate film, the power generation performance can be improved, and the gas seal performance can be improved.

(A) is a perspective view showing a solid oxide fuel cell, (b) is a plan view showing a state in which a fuel electrode and an interconnector are embedded in a recess, and showing a region where an intermediate film is formed by an alternate long and short dash line is there. (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 top view which shows an interconnector and its vicinity in the state which removed the air electrode current collection part. 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 of FIG. (A) is sectional drawing corresponding to the 7-7 line | wire of FIG. 5, (b) is sectional drawing which shows the state which formed each layer in the 1st recessed part. FIG. 2 is a cross-sectional view of a solid oxide fuel cell in which seal layers are formed on four side surfaces of a third recess, where (a) shows a state in which an end of an intermediate film is located inside an end of a solid electrolyte membrane; ) Shows a state in which the end of the intermediate membrane and the end of the solid electrolyte membrane are substantially at the same position, and (c) shows a state in which the end of the solid electrolyte membrane is covered with the intermediate membrane.

  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 2 have a structure called a so-called “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 representative 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 generating element portions A and A in 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. A cuboid-shaped depression defined by a circumferentially closed side wall (two side walls along the longitudinal direction (x-axis direction) and two side walls along the width direction (y-axis direction)) made of the material of the support substrate 10 It is.

  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 (x-axis direction) are made of the material of the support substrate 10, and the two side walls along the width direction (y-axis direction) are the anode current collector 21. Made of material.

  The entire fuel electrode active portion 22 is embedded (filled) in each second recess 21a. Accordingly, each fuel electrode active portion 22 has 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 and a bottom surface along the width direction (y-axis direction) of each anode active portion 22 are in contact with the anode current collecting portion 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 (x-axis direction) are made of the material of the support substrate 10, and the two side walls along the width direction (y-axis direction) are the anode current collector 21. Made of material.

  An interconnector (conductive dense body) 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 third recess 21b.

  The upper surface (outer surface) of the fuel electrode 20 (the fuel electrode current collector 21 and the fuel electrode active unit 22), the upper surface (outer surface) of the interconnector 30, and the main surface of the support substrate 10 form one plane (recessed portion). The same plane as the main surface of the support substrate 10 when 12 is not formed) is formed. That is, no step is formed between the upper surface of the fuel electrode 20, 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. More 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.

Each of the portions where the plurality of interconnectors 30 are formed on the outer peripheral surface extending in the longitudinal direction (the arrangement direction of the power generating element portions A) of the support substrate 10 in a state where the fuel electrode 20 is embedded in each of the first recesses 12. The entire surface excluding the central portion in the longitudinal direction is covered with the solid electrolyte membrane 40. The solid electrolyte membrane 40 is a fired body made of a dense material having ion conductivity and not electron conductivity (insulating property). The solid electrolyte membrane 40 can be made of, for example, YSZ (yttria stabilized zirconia). Or you may comprise from LSGM (lantern gallate). The thickness of the solid electrolyte membrane 40 is 3 to 50 μm.

  Almost the entire outer surface of the solid electrolyte membrane 40 is covered with an intermediate film 50. The intermediate film 50 is a fired body made of a dense ceria-based material, is a layer that suppresses a reaction between the solid electrolyte film 40 and the air electrode 60, and is also referred to as a reaction prevention film.

  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 first recess 12 is formed from the interconnector 30 and the laminate of the solid electrolyte membrane 40 and the intermediate membrane 50. It is covered with a dense gas barrier layer. This gas barrier layer exhibits a gas seal function that prevents mixing of the fuel gas flowing in the space inside the gas barrier layer and the air flowing in the space outside the gas barrier layer.

The intermediate film 50 is a dense body made of a ceria-based (CeO ₂ -based) material and has a porosity of 10% or less, particularly 1 to 5%. The intermediate film 50 can be formed with a composition containing Ce and another rare earth element other than Ce. For example, (CeO ₂ ) _1-x (REO _1.5 ) _x (wherein RE is Sm , Y, Yb, and Gd, and x preferably has a composition represented by the following formula: 0 <x ≦ 0.3. Furthermore, from the viewpoint of reducing electric resistance, it is preferable to use Sm or Gd as RE, and for example, it is preferable to consist of CeO ₂ in which 15 to 25 mol% of SmO _1.5 or GdO _1.5 is dissolved. . The thickness of the intermediate film 50 is set to 1.5 to 50 μm from the viewpoint of preventing peeling and maintaining high power generation performance.

  By interposing the intermediate film 50 between the solid electrolyte membrane 40 and the air electrode 60, YSZ in the solid electrolyte membrane 40 and Sr in the air electrode 60 react in the cell during cell production or in operation. Thus, the occurrence of a phenomenon in which a reaction layer having a large electric resistance is formed at the interface between the solid electrolyte membrane 40 and the air electrode 60 can be suppressed.

  In addition, since the intermediate film 50 is laminated not only between the solid electrolyte film 40 and the air electrode 60 but also as a gas barrier layer, the solid electrolyte film 40 is thinned to improve power generation performance. Even if it makes it, the intermediate film 50 is laminated | stacked on the outer surface, the gas leakage from the solid electrolyte membrane 40 can be suppressed with the intermediate film 50, and gas sealing performance can be improved.

  2A, in this embodiment, the solid electrolyte membrane 40 and the intermediate membrane 50 are provided on the upper surface of the fuel electrode 20 (the fuel electrode current collector 21 + the fuel electrode active portion 22) and the upper surface of the interconnector 30. The both side ends in the longitudinal direction and the main surface of the support substrate 10 are covered. Here, as described above, no step is formed between the upper surface of the fuel electrode 20, the upper surface of the interconnector 30, and the main surface of the support substrate 10. Therefore, the solid electrolyte membrane 40 and the intermediate membrane 50 are flattened. As a result, the generation of cracks in the solid electrolyte film 40 and the intermediate film 50 due to stress concentration can be suppressed as compared with the case where a step is formed in the solid electrolyte film 40 and the intermediate film 50. And the fall of the gas seal function which the intermediate film 50 has can be suppressed.

  In this embodiment, the end in the arrangement direction (x-axis direction) of the intermediate film 50 laminated on the solid electrolyte membrane 40 is positioned above the interconnector 30 and laminated on both ends of the interconnector 30. The solid electrolyte membrane 40 is located on the inner side by a predetermined distance L1 from the end in the arrangement direction. Since the end of the intermediate film 50 in the arrangement direction is positioned above the interconnector 30, the solid electrolyte film 40 and the intermediate film 50 are laminated on the surfaces of the porous fuel electrode 20 and the support substrate 10. In addition, the portion of only the solid electrolyte membrane 40 is eliminated, and the gas sealing performance can be further improved.

  Further, as shown in FIG. 3, solid electrolyte membranes 40 are stacked on both ends of the interconnector 30 in the array orthogonal direction (y-axis direction) orthogonal to the array direction, and the end of the intermediate film 50 in the array orthogonal direction is The intermediate film 50 is laminated on the solid electrolyte 40 so as to be located above the connector 30 and to be located at a predetermined distance B1 from the end of the solid electrolyte film 40 in the direction orthogonal to the arrangement. The predetermined distances L1 and B1 are, for example, 0.01 to 0.5 mm.

  That is, the upper surface of the outer peripheral portion of the interconnector 30 is covered with the solid electrolyte membrane 40, and the intermediate membrane 50 is laminated on the upper surface of the solid electrolyte membrane 40 so that the solid electrolyte membrane 40 is exposed in an annular shape. Thereby, gas seal performance and power generation performance can be further improved.

  An air electrode 60 is formed on the upper surface of a portion of the solid electrolyte membrane 40 that is in contact with each fuel electrode active portion 22 via an intermediate film 50. The intermediate 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 air electrode 60 viewed from above is substantially the same rectangle as the fuel electrode active part 22.

  Here, the laminated body formed by laminating the fuel electrode 20, the solid electrolyte membrane 40, the intermediate membrane 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.

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.

  Regarding the adjacent power generation element portions A and A, the air electrode 60 of one power generation element portion A (left side in FIG. 2A) and the other power generation element portion A (right side in FIG. 2A). An air electrode current collector film 70 is formed on the air electrode 60, the intermediate film 50, 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, the “air electrode current collector film 70 and the interconnector 30” having electronic conductivity correspond to the “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. 4, the fuel gas (hydrogen gas or the like) flows through the fuel gas flow path 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 “a gas containing oxygen” (air or the like) (or flowing a gas containing oxygen along the upper and lower surfaces of the support substrate 10), the solid electrolyte membrane 40 An electromotive force is generated by a difference in oxygen partial pressure generated between the two side 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 ⁻ (in the 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 part A on the frontmost side and the air electrode 60 of the power generating element part A on the farthest side in FIG. 4).

(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. 5 to 6, “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. 5 is prepared. The support substrate molded body 10g is produced by using a method such as extrusion molding or cutting using a slurry obtained by adding a binder or the like to the material of the support substrate 10 (for example, NiO + MgO). .

  Next, as shown in FIG. 6B, the molded body 21g of the fuel electrode current collector is embedded and formed in each first recess formed in the upper and lower surfaces of the molded body 10g of the support substrate. Next, a molded body 22g of the fuel electrode active part is embedded and formed in each second recess formed on the outer surface of the molded body 21g of each fuel electrode current collector. Further, the molded body 21g of each fuel electrode current collector and each fuel electrode active part 22g use, for example, a slurry obtained by adding a binder or the like to the powder of the material of the fuel electrode 20 (for example, Ni and YSZ). Then embed and form using printing methods.

Subsequently, the interconnector is molded in each third recess formed in the “surface portion excluding the portion where the molded body 22g of the fuel electrode active portion is embedded” on the outer surface of the molded body 21g of each fuel electrode current collector. Each body 30g is embedded and formed. 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 plurality of interconnectors are formed on the outer peripheral surface extending in the longitudinal direction of the molded body 10g of the support substrate in which the plurality of molded fuel electrode bodies (21g + 22g) and the plurality of interconnector molded bodies 30g are embedded and formed. A molded membrane of a solid electrolyte membrane is formed on the entire surface excluding the central portion in the longitudinal direction of each portion where the molded body 30g is formed. The molded membrane of the solid electrolyte membrane is formed by using a slurry obtained by adding a binder or the like to the powder of the material of the solid electrolyte membrane 40 (for example, YSZ), using a printing method, a dipping method, or the like.

Next, a molded film of an intermediate film is formed on the outer surface of the molded film of the solid electrolyte film. The formed film of each intermediate film is formed using a slurry obtained by adding a binder or the like to the powder of the material of the intermediate 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 of the state in which the air electrode 60 and the air electrode current collection part 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 intermediate 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, for adjacent power generation element parts, the air electrode molding film, the intermediate film 50, and the air electrode molding film of the other power generation element part A and the interconnector 30 of one power generation element part A are straddled. And the molding film of an air electrode current collection part is formed in the outer surface of the interconnector 30. FIG.

  The forming film of each air electrode current collector is formed by using a printing method or the like using a slurry obtained by adding a binder or the like to the powder of the material of the air electrode current collector 70 (for example, LSCF), for example. 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)
As described above, in the “horizontal stripe type” cell according to the embodiment of the present invention, the entire outer peripheral surface extending in the longitudinal direction of the support substrate 10 has the interconnector 30, the solid electrolyte membrane 40, and the intermediate membrane 50. The intermediate membrane 50 reinforces the thin solid electrolyte membrane 40 and flows through the space inside the gas barrier layer and the space outside the gas barrier layer. The air can be reliably shut off. Even if the solid electrolyte membrane 40 is thinned to improve the power generation performance, the gas sealing performance can be improved because the intermediate film 50 is formed on the outer surface of the solid electrolyte membrane 40.

  Furthermore, although the intermediate film 50 made of a ceria-based material has not only ionic conductivity but also electrical conductivity, the solid electrolyte film 40 in which the end of the intermediate film 50 in the arrangement direction is stacked on both ends of the interconnector 30. Therefore, the intermediate film 50 and the interconnector 30 do not come into contact with each other, and therefore no short circuit occurs between the adjacent power generation element portions A.

  In addition, 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 (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 is filled and embedded with the members such as the fuel electrode 20 (the fuel electrode current collector 21 + the fuel electrode active portion 22) and the interconnector 30 in the first recesses 12 of the support substrate 10 without any gaps. And the embedded member are co-sintered. Therefore, a sintered body having high bondability between members and high reliability can be obtained.

Further, the interconnector 30 is embedded in a third recess 21b formed on the outer surface of the fuel electrode current collector 21, and as a result, two side surfaces along the width direction (y-axis direction) of the rectangular interconnector 30 are formed. And the bottom surface are in contact with the anode current collector 21 in the recess 21b. Therefore, the fuel electrode 20 (the current collector 21) and the interconnector 30 are compared to the case where a configuration in which the rectangular parallelepiped interconnector 30 is laminated (contacted) on the outer plane of the fuel electrode current collector 21 is employed. The area of the interface with can be increased. Therefore, the electronic conductivity between the fuel electrode 20 and the interconnector 30 can be increased, and as a result, the power generation output of the fuel cell can be increased.

  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. 5 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 20 is composed of two layers of the fuel electrode current collector 21 and the fuel electrode active portion 22, but the fuel electrode 20 is a single layer corresponding to the fuel electrode active portion 22. It may be configured.

  FIG. 7 shows another embodiment, and a dense sealing layer 75 having insulating properties is formed between the side wall of the third recess 21 b and the interconnector 30. The seal layer 75 surrounds the periphery of the interconnector 30, and the upper surface constitutes a flat surface having no step from the upper surface of the support substrate 10, the fuel electrode 20, and the interconnector 30. The solid electrolyte membrane 40 and the intermediate membrane 50 are laminated so as to extend to both ends of the sealing layer 75 in the arrangement direction of the power generating element portion A, and are not laminated on the interconnector 30. In other words, the end of the intermediate film 50 in the arrangement direction of the power generation element portion A is located above the seal layer 75 and does not exist above the interconnector 30.

That is, the seal layer 75 is a fired body made of a dense material having electrical insulation. The seal layer 75 contains, for example, a metal oxide, and preferably contains a metal oxide as a main component. Specifically, the metal oxide contains at least one oxide selected from the group consisting of (AE) ZrO ₃ , MgO, MgAl ₂ O ₄ , and Ce _x Ln _1-x O _2. Also good. Here, AE is an alkaline earth metal, Ln is at least one element selected from the group consisting of Y and a lanthanoid, and x satisfies 0 <x ≦ 0.3. Examples of elements corresponding to AE include Mg, Ca, Sr, and Ba. Moreover, transition metal oxides (for example, NiO, Mn ₃ O ₄ , Fe ₂ O ₃ , Cr ₂ O ₃ , CoO) may be included as a trace component. These components may exist as an oxide, or at least one selected from the group consisting of “(AE) ZrO ₃ , MgO, MgAl ₂ O ₄ , and Ce _x Ln _1-x O _2. It may be present in the form of a solid solution in the oxide. The average particle size of the metal oxide is preferably from 0.1 to 5.0 μm, more preferably from 0.3 to 4.0 μm. The thickness of the seal layer 75 is 10 to 100 μm.

FIG. 7A shows the case where the end in the arrangement direction (x-axis direction) of the intermediate film 50 laminated on the solid electrolyte membrane 40 is separated from the interconnector 30 by a predetermined distance L2. ) In the arrangement direction (x-axis direction), the end of the intermediate film 50 and the end of the solid electrolyte membrane 40 are substantially at the same position, and the end of the intermediate film 50 in the arrangement direction is a predetermined distance L2 from the interconnector 30. 7C, the end of the solid electrolyte membrane 40 is covered with the intermediate film 50, and the end of the intermediate film 50 in the arrangement direction is separated from the interconnector 30 by a predetermined distance L2. Shows the case. The air electrode current collector 70 is formed between the adjacent power generation element portions A and separated from the one intermediate film 50.

  Even in such a cell, the power generation performance can be improved, the gas seal performance can be improved, and the intermediate film 50 and the interconnector 30 are not in contact with each other. Short circuit can be surely prevented.

  Even in this case, the solid electrolyte membrane 40 is laminated on both ends of the seal layer 75 in the arrangement orthogonal direction orthogonal to the arrangement direction, and the end of the intermediate film 50 in the arrangement orthogonal direction is a predetermined distance from the interconnector 30. The intermediate film 50 is desirably laminated on the solid electrolyte film 40 so as to be separated by B.

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 (conductive dense body)
40 ... Solid electrolyte membrane 50 ... Intermediate membrane 60 ... Air electrode 70 ... Air electrode current collector 75 ... Seal layer A ... Power generation element

Claims (5)

A flat porous support substrate having a gas flow path formed therein;
A plurality of power generating element portions each provided in a plurality of locations separated from each other on the main surface of the plate-like support substrate, wherein at least a fuel electrode, a solid electrolyte, an intermediate film, and an air electrode are laminated;
A plurality of electrical connection portions that are provided between the adjacent power generation element portions and electrically connect the fuel electrode of one of the power generation element portions and the air electrode of the other power generation element portion;
The intermediate film is a dense body made of a ceria-based material having electrical conductivity ,
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 assembly of the corresponding power generation element unit is provided in each first recess. Each electrical part is 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. A portion of the electrical connection portion is embedded in a third recess formed on the outer surface of the fuel electrode current collector that is embedded and embedded in the first recess, the position being different from the position where the second recess is formed. The conductive dense body that constitutes it is embedded,
The solid electrolyte laminated on the anode active portion is laminated on both end portions of the conductive dense body in the arrangement direction of the power generating element and said one and extends from both sides of the other of the power generating element, the further both ends of the arrangement direction of the middle ligament is, the solid solid oxide fuel cell, wherein the electrolyte through the positioned above the conductive dense material. Both ends of the arrangement direction of the intermediate membrane, and being located inwardly from both ends of the arrangement direction of the solid electrolyte laminated on both end portions of the conductive dense material by a predetermined distance L1 The solid oxide fuel cell according to claim 1. A flat porous support substrate having a gas flow path formed therein;
A plurality of power generating element portions each provided in a plurality of locations separated from each other on the main surface of the plate-like support substrate, wherein at least a fuel electrode, a solid electrolyte, an intermediate film, and an air electrode are laminated;
A plurality of electrical connection portions that are provided between the adjacent power generation element portions and electrically connect the fuel electrode of one of the power generation element portions and the air electrode of the other power generation element portion;
The intermediate film is a dense body made of a ceria-based material having electrical conductivity ,
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 assembly of the corresponding power generation element unit is provided in each first recess. Each electrical part is 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. A portion of the electrical connection portion is embedded in a third recess formed on the outer surface of the fuel electrode current collector that is embedded and embedded in the first recess, the position being different from the position where the second recess is formed. A conductive dense body is embedded, and a dense sealing layer having insulating properties is disposed between the conductive dense body and the side wall of the third recess,
The solid electrolyte laminated on the fuel electrode active part is extended from both sides of the one and the other power generation element part and laminated on both end parts of the seal layer in the arrangement direction of the power generation element, and the intermediate film the so that both ends in the array direction is located above the sealing layer through the solid electrolyte, the solid oxide fuel cell, wherein an intermediate layer is laminated on the solid electrolyte. Wherein both ends of the arrangement direction of the intermediate membrane, solid oxide fuel cell according to claim 3, characterized in that spaced apart by a predetermined distance L2 from the conductive dense material. The solid electrolyte is laminated on both end portions of the sealing layer in the array direction orthogonal to the array direction, both ends of the arrangement direction perpendicular to the intermediate film, spaced apart from said conductive dense material by a predetermined distance B2 The solid oxide fuel cell according to claim 3 or 4, wherein