JP5752287B1 - Fuel cell - Google Patents

Abstract

[PROBLEMS] To provide a fuel cell of “horizontal stripe type”, which prevents a fuel gas deficiency and an abnormal temperature rise in a power generation element portion at a fuel discharge end, and further has a large number of “a plurality of power generation element portions in a longitudinal direction”. To do. A plurality of power generating element portions A electrically connected in series along the longitudinal direction are formed on the front and back main surfaces of a flat support substrate 10 having a longitudinal direction (x-axis direction). Is done. Of the plurality of power generation element portions A in the longitudinal direction, the power generation element portion A that is closest to the gas discharge side end portion (x-axis negative direction side) of the support substrate 10 is particularly referred to as an end power generation element portion As. For each of the front and back surfaces of the support substrate 10, the areas contributing to power generation of the remaining power generation element portions A other than the end power generation element portions As are equal in area S1, and the areas contributing to power generation of the end power generation element portions As. S2 is larger than area S1. The ratio of the area S2 to the area S1 (S2 / S1) is preferably 1.1 to 2.2. [Selection] Figure 2

Description

  The present invention relates to a fuel cell.

  Conventionally, “a support substrate having a longitudinal direction and a gas flow path formed therein along the longitudinal direction” and “a plurality of locations on the surface of the support substrate separated from each other along the longitudinal direction” A plurality of power generation element portions each including at least a fuel electrode, a solid electrolyte membrane, and an air electrode, and “one fuel electrode and the other air electrode of the adjacent power generation element portions,” respectively. 2. Description of the Related Art A solid oxide fuel cell (SOFC) including an “electrically connecting portion that is electrically connected” is known (see, for example, Patent Documents 1 and 2). Such a configuration is also called a “horizontal stripe type”.

Japanese Patent No. 5095877 Japanese Patent No. 4541296

  In Patent Document 2, the areas of a plurality of power generation element portions provided on the support substrate along the longitudinal direction of the support substrate (area contributing to power generation; the area where the fuel electrode, the solid electrolyte membrane, and the air electrode face each other) are described. A configuration is disclosed in which the fuel gas gradually increases along the flow direction of the fuel gas. According to this configuration, the following two actions and effects can occur.

  First, firstly, the fuel gas flowing through the gas flow path formed inside the support substrate is gradually consumed in the process of moving from the inflow side to the discharge side of the gas flow path. Therefore, in the process in which the fuel gas moves from the inflow side to the discharge side, the concentration of the fuel gas gradually decreases. In other words, the concentration of the fuel gas supplied to the fuel electrodes of the plurality of power generation element portions provided on the support substrate along the longitudinal direction of the support substrate decreases sequentially along the fuel gas flow direction. If the concentration of the fuel gas supplied to the fuel electrode of the power generation element is too low, the oxygen moving from the air electrode through the solid electrolyte membrane to "near the interface with the solid electrolyte membrane in the fuel electrode" The fuel gas (specifically, hydrogen) that moves to the vicinity of the interface via the fuel electrode may be insufficient. Thus, when the fuel gas is insufficient, Ni present in the vicinity of the interface changes to NiO due to the atmosphere in the vicinity of the interface becoming an oxidizing atmosphere. As a result, there may occur a problem (hereinafter referred to as “first problem”) in which the reaction resistance in the vicinity of the interface increases and the power generation efficiency of the power generation element portion decreases. From the above, this first problem is likely to occur in the power generation element portion close to the end portion on the fuel gas discharge side in the longitudinal direction of the support substrate (hereinafter referred to as “support substrate discharge side end portion”). In particular, it is most likely to occur at the power generation element portion closest to the discharge side end portion of the support substrate.

  Here, it is known that the above-described “situation in which Ni changes to NiO due to a shortage of fuel gas” is less likely to occur as the current density through the power generation element portion decreases. In other words, the first problem is less likely to occur as the current density of the power generation element portion decreases. In this respect, since the plurality of power generation element portions provided on the support substrate along the longitudinal direction of the support substrate are electrically connected in series, the magnitudes of the currents passing through the power generation element portions are equal to each other. Accordingly, as described in Patent Document 2, when the areas of the plurality of power generation element portions are sequentially increased along the flow direction of the fuel gas, the current density of the plurality of power generation element portions becomes the flow direction of the fuel gas. It becomes small sequentially along. That is, the current density of the power generation element portion near the discharge side end portion of the support substrate is reduced. As a result, the first problem is less likely to occur in the “power generation element portion near the discharge side end of the support substrate” where the first problem is likely to occur.

  Secondly, excess fuel gas discharged from the discharge side end of the support substrate can react with air existing near the discharge side end of the support substrate and fuel. Since the heat resulting from the combustion is transmitted to the discharge side end of the support substrate, the temperature of the discharge side end of the support substrate (and hence the temperature of the power generation element near the discharge side end of the support substrate) is excessively high. (Hereinafter, referred to as “second problem”) may occur. In this regard, as the current density of the power generation element portion is smaller, the temperature increase of the power generation element portion due to the reaction can be suppressed. Therefore, as described in Patent Document 2, if the current density of the “power generation element portion close to the discharge-side end portion of the support substrate” is small, the second problem is likely to occur. The second problem is less likely to occur in the “power generation element portion close to”.

  By the way, in the above-described “horizontal stripe type” fuel cell, in order to obtain a larger output voltage, it is desired to increase the number of “a plurality of power generation element portions provided on the support substrate along the longitudinal direction of the support substrate” as much as possible. There is a request. In this regard, in the “configuration in which the area of the plurality of power generation element portions sequentially increases along the flow direction of the fuel gas” described in Patent Document 2, the “number of the plurality of power generation element portions in the longitudinal direction” There was room for improvement in terms of growth.

  The present invention is to cope with such a problem, and is a “horizontal stripe type” fuel cell having a longitudinal direction, in which the first and second problems are unlikely to occur, An object of the present invention is to provide a large number of power generating element parts.

  The fuel cell according to the present invention is a “horizontal stripe type” fuel cell having the same configuration as the fuel cell described in the “Background Art” section.

  The fuel cell according to the present invention is characterized in that the remaining power generation elements other than the power generation element part (= end power generation element part) closest to the discharge side end of the support substrate among the plurality (three or more) of power generation element parts. The area contributing to power generation of the plurality of power generation element portions is a first area, and the area contributing to power generation of the end power generation element portion is a second area larger than the first area. In other words, for a plurality of power generation element portions in the longitudinal direction, the areas of a plurality of (two or more) power generation element portions other than the end power generation element portions are equal, and the area of the end power generation element portion is , Larger than the area of the power generation element portion other than the end power generation element portion.

  According to this, for example, “the areas of the respective power generation element portions located at both ends in the longitudinal direction of the plurality of power generation element portions” are described in the configuration according to the feature of the present invention and in Patent Document 2. Compared with the configuration described in Patent Document 2 above, the above-described configuration of the present invention is compared under the condition that “the areas of the plurality of power generation element portions are sequentially increased along the flow direction of the fuel gas”. With the configuration according to the feature, it is possible to increase the number of the plurality of power generation element portions in the longitudinal direction. In addition, the first and second problems are substantially generated in the power generation element portion (that is, the end power generation element portion) closest to the discharge side end portion of the support substrate, and the other problems It does not occur remarkably in the “power generation element portion near the discharge-side end portion of the support substrate”. Therefore, it is considered that the first and second problems can hardly occur by increasing the area of only the end power generation element portion and reducing the current density of only the end power generation element portion. As described above, according to the above configuration, it is possible to provide a device in which the first and second problems are unlikely to occur and the “number of the plurality of power generation element portions in the longitudinal direction” is large.

  When the ratio (S2 / S1) of the second area (S2) to the first area (S1) is 1.1 to 2.2, the inventor limits the limit fuel of the fuel cell. It has been found that the utilization rate is good and that the end power generation element portion hardly peels off (this will be described in detail later).

  In the fuel cell according to the present invention, a portion (hereinafter referred to as “end connection”) that electrically connects the end power generation element portion in the electrical connection portion and the power generation element portion adjacent to the end power generation element portion. The portion where the cross-sectional area (in the direction perpendicular to the direction in which electricity flows) is electrically connected between the adjacent power generation element portions other than the end power generation element portions in the electrical connection portion It is preferable that the cross-sectional area is larger.

  In the configuration according to the above feature of the present invention, only the power generation element portion adjacent in the longitudinal direction is electrically connected, which constitutes the “electrical connection portion” because only the area of the end power generation element portion is large. Among the plurality of portions, the length in the longitudinal direction of only the end connection portion is likely to be longer than the length in the longitudinal direction of the remaining portions. In other words, the resistance of only the end connection portion is likely to be larger than the resistance of the remaining portions. On the other hand, according to the said structure, since the cross-sectional area of the said edge part connection part is large, the resistance of the said edge part connection part can be made small. As a result, the power generation efficiency of the fuel cell as a whole can be increased.

1 is a perspective view showing a fuel cell according to the present invention. It is sectional drawing corresponding to the 2-2 line of FIG. It is sectional drawing to which a part of FIG. 2 was expanded. FIG. 4 is a cross-sectional view corresponding to line 4-4 of FIG. It is the top view which showed the state of the fuel electrode and interconnector which were embed | buried under the recessed part of the support substrate shown in FIG. FIG. 6 is a cross-sectional view corresponding to line 6-6 in FIG. It is a figure for demonstrating the operation state of the fuel cell shown in FIG. It is a figure for demonstrating the flow of the electric current in the operating state of the fuel cell shown in FIG. It is a perspective view which shows the support substrate shown in FIG. FIG. 4 is a cross-sectional view corresponding to FIG. 3 in a first stage in the manufacturing process of the fuel cell shown in FIG. 1. FIG. 4 is a cross-sectional view corresponding to FIG. 3 in a second stage in the manufacturing process of the fuel cell shown in FIG. 1. FIG. 4 is a cross-sectional view corresponding to FIG. 3 in a third stage in the manufacturing process of the fuel cell shown in FIG. 1. FIG. 4 is a cross-sectional view corresponding to FIG. 3 in a fourth stage in the manufacturing process of the fuel cell shown in FIG. 1. FIG. 4 is a cross-sectional view corresponding to FIG. 3 in a fifth stage in the manufacturing process of the fuel cell shown in FIG. 1. FIG. 4 is a cross-sectional view corresponding to FIG. 3 in a sixth stage in the manufacturing process of the fuel cell shown in FIG. 1. FIG. 6 is a cross-sectional view corresponding to FIG. 3 in a seventh stage in the manufacturing process of the fuel cell shown in FIG. 1. FIG. 4 is a cross-sectional view corresponding to FIG. 3 in an eighth stage in the manufacturing process of the fuel cell shown in FIG. 1. The areas of the plurality of power generation element parts A other than the end power generation element part As are equal, and the area of the end power generation element part As is larger than the area of the power generation element part A other than the end power generation element part As, It is a figure for demonstrating. It is a figure corresponding to FIG. 2 in the 1st modification of the fuel cell which concerns on this invention. It is a figure corresponding to FIG. 18 in the 1st modification shown in FIG. It is a figure corresponding to FIG. 2 in the 2nd modification of the fuel cell which concerns on this invention. It is a figure corresponding to FIG. 18 in the 2nd modification shown in FIG.

(Constitution)
1 and 2 show the whole of a solid oxide fuel cell (SOFC) according to an embodiment of the present invention. FIG. 3 is an enlarged view of a part of the cross section shown in FIG. This SOFC is electrically connected in series to each of the upper and lower surfaces (main surfaces (planes) on both sides parallel to each other) of the flat support substrate 10 having a longitudinal direction (x-axis direction) (this example). Then, the four power generating element portions A are arranged at a predetermined interval in the longitudinal direction, and have a so-called “horizontal stripe type” configuration.

  The shape of the entire SOFC as viewed from above is, for example, a rectangle whose length in the longitudinal direction is 50 to 500 mm and whose length in the width direction (y-axis direction) perpendicular to the longitudinal direction is 10 to 100 mm. The total thickness of this SOFC is 1-5 mm.

  The support substrate 10 is a flat plate-like fired body made of a porous material having no electronic conductivity. As shown in FIG. 9 to be described later, a plurality of (six in this example) fuel gas passages 11 (through holes) extending in the longitudinal direction are provided in the support substrate 10 at predetermined intervals in the width direction. Is formed. In addition, in each of the upper and lower surfaces (both main surfaces) of the support substrate 10, recesses 12 are formed at locations corresponding to the respective power generation element portions A. In this example, each recess 12 includes a bottom wall made of the material of the support substrate 10 and side walls closed in the circumferential direction made of the material of the support substrate 10 over the entire circumference (two side walls along the longitudinal direction and the width direction). A rectangular parallelepiped depression defined by two side walls).

The support substrate 10 can be made of, for example, CSZ (calcia stabilized zirconia). Alternatively, it may be composed of NiO (nickel oxide) and YSZ (8YSZ) (yttria stabilized zirconia), NiO (nickel oxide) and Y ₂ O ₃ (yttria), or MgO. (Magnesium oxide) and MgAl ₂ O ₄ (magnesia alumina spinel) may be used.

  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.

  As shown in FIGS. 3 to 5, the entire fuel electrode current collector 21 is embedded (filled) in each recess 12 formed on the upper and lower surfaces (both main surfaces) of the support substrate 10. Therefore, each fuel electrode current collector 21 has a rectangular parallelepiped shape. As shown in FIG. 5, a recess 21 a is formed on the upper surface (outer surface) of each fuel electrode current collector 21. Each recess 21a includes a bottom wall made of the material of the fuel electrode current collector 21 and a circumferentially closed side wall made of the material of the fuel electrode current collector 21 (two side walls and a width along the longitudinal direction). Two side walls extending in the direction), and a rectangular parallelepiped-shaped depression.

  The entire anode active portion 22 is embedded (filled) in each 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. The entire circumference and bottom surface of the “side wall closed in the circumferential direction” of each anode active portion 22 are in contact with the anode current collector 21 in the recess 21b.

  As shown in FIG. 5, a recess 21 b is formed on the upper surface (outer surface) of each fuel electrode current collector 21 except for the recess 21 a. Each recess 21b includes a bottom wall made of the material of the fuel electrode current collector 21 and a side wall made of the material of the fuel electrode current collector 21 over the entire circumference (two side walls and a width along the longitudinal direction). Two side walls extending in the direction), and a rectangular parallelepiped-shaped depression.

  The entire interconnector 30 is embedded (filled) in each 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 entire circumference and bottom surface of the “circumferentially closed sidewall” of each interconnector 30 are in contact with the fuel electrode current collector 21 in the recess 21b.

  As shown in FIG. 3, 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 Thus, one plane (the same plane as the main surface of the support substrate 10 when the recess 12 is not formed) is configured. 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 can be composed of, for example, NiO (nickel oxide) and YSZ (8YSZ) (yttria stabilized zirconia). Or you may comprise 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 (8YSZ) (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 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 oxygen ion conductivity. The “volume ratio of the substance having oxygen ion conductivity with respect to the entire volume excluding the pore portion” in the anode active portion 22 is “having oxygen ion conductivity with respect to the entire volume excluding the pore portion” in the anode current collecting portion 21. It is larger than the “volume ratio of the substance”.

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.

  The entire surface excluding the central portion of each portion where the plurality of interconnectors 30 are formed on the outer peripheral surface extending in the longitudinal direction of the support substrate 10 in a state where the fuel electrode 20 and the interconnector 30 are embedded in the respective recesses 12, The solid electrolyte membrane 40 is covered. That is, the solid electrolyte membrane 40 extends from the inside of the power generation element portion A to the outside of the power generation element portion A so as to cover the surface of the support substrate 10. In other words, the solid electrolyte membrane 40 is a portion excluding the region where the power generating element part A is provided on each of the main surfaces on the front and back sides of the support substrate 10 and the side end surface (width direction (y-axis direction)) of the support substrate 10. Are provided so as to cover the both end faces of the head. Here, in the solid electrolyte membrane 40, “a portion excluding the region where the power generating element portion A is provided on each of the main surfaces on the front and back sides of the support substrate 10 and the side end surface (width direction (y-axis direction) of the support substrate 10”. “Parts covering both end faces” correspond to “dense film”.

The solid electrolyte membrane 40 is a fired body made of a dense material having ion conductivity. The solid electrolyte membrane 40 can be made of, for example, YSZ (8YSZ) (yttria stabilized zirconia). That is, the solid electrolyte membrane 40 contains zirconia (ZrO ₂ ). The thickness of the solid electrolyte membrane 40 is 3 to 50 μm.

  Thus, the whole area of each main surface of the front and back of the support substrate 10 and the side end surface of the support substrate 10 are portions corresponding to the interconnector 30 and the solid electrolyte membrane 40 (inside (part) of the power generation element portion A). And a portion corresponding to the outside of the power generation element portion A (including the “dense film”) and a “dense film” composed of the dense element. This “dense membrane” exhibits a gas sealing function that prevents mixing of the fuel gas flowing in the space inside the membrane and the air flowing in the space outside the membrane. In order to exhibit this gas sealing function, the porosity of this “membrane made of dense material” (interconnector 30 + solid electrolyte membrane 40) is 10% or less. This “dense film” corresponds to a part of the “seal portion”.

  As shown in FIG. 2, in this example, the solid electrolyte membrane 40 includes the upper surface of the fuel electrode 20 (current collector 21 + active portion 22), the central portion of the upper surface of the interconnector 30, and the main surface of the support substrate 10. Covering. 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 is flattened. As a result, compared with the case where a step is formed in the solid electrolyte membrane 40, the generation of cracks in the solid electrolyte membrane 40 due to stress concentration can be suppressed, and the gas sealing function of the solid electrolyte membrane 40 is reduced. Can be suppressed.

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

The reaction preventing film 50 is a dense material containing ceria containing rare earth elements such as GDC = (Ce, Gd) O ₂ (gadolinium doped ceria) and SDC = (Ce, Sm) O ₂ (samarium doped ceria). Composed of materials. The thickness of the reaction preventing film 50 is 3 to 50 μm. The porosity of the reaction preventing film 50 is 10% or less. In the present embodiment, the reaction preventing film 50 made of a dense material corresponds to the remaining part of the “seal part”. In other words, in the present embodiment, the “seal portion” includes the interconnector 30, the solid electrolyte membrane 40 (including portions corresponding to the inside and outside of the power generation element portion A), and the reaction preventing membrane 50. .

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.

Note that the reaction preventing film 50 is interposed between the solid electrolyte membrane 40 and the air electrode 60 because the YSZ in the solid electrolyte membrane 40 and the Sr in the air electrode 60 in the SOFC being manufactured or in operation. This is to suppress the occurrence of a phenomenon in which a reaction layer (SrZrO ₃ ) having a large electric resistance is formed at the interface between the solid electrolyte membrane 40 and the air electrode 60 due to the reaction.

  Here, a laminated body in which the fuel electrode 20 (particularly, the fuel electrode active part 22), the solid electrolyte membrane 40, the reaction preventing film 50, and the air electrode 60 are laminated (more specifically, the laminated body). The region where the fuel electrode active part 22 and the air electrode 60 face each other) corresponds to the “power generation element part A” (see FIGS. 2 and 3). In the present embodiment, as shown in FIG. 2, a plurality (four in this example) of power generation element portions A are arranged at predetermined intervals in the longitudinal direction on each of the upper and lower surfaces of the support substrate 10. ing.

  As shown in FIG. 2, for the adjacent power generation element portions A and A, the air electrode 60, the solid state so as to straddle the air electrode 60 of one power generation element portion A and the interconnector 30 of the other power generation element portion A. An air electrode current collecting film 70 is formed on the electrolyte film 40 (= the “dense film”) and the upper surface of 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, LSC = (La, Sr) CoO ₃ (lanthanum strontium cobaltite) may be used. Or you may comprise from Ag (silver) and Ag-Pd (silver palladium alloy). Alternatively, it may be composed of La (Ni, Fe, Cu) O ₃ . That is, the air electrode current collector film 70 contains strontium (Sr) or lanthanum (La). 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 manner, as shown in FIG. 2, the air electrode 60 of one power generation element part A and the other of the adjacent power generation element parts A and A, as shown in FIG. The fuel electrode 20 (particularly, the fuel electrode current collector 21) of the power generation element part A is electrically connected via the “air electrode current collector film 70 and the interconnector 30” having electronic conductivity. As a result, a plurality (four in this example) of power generation element portions A disposed on the upper and lower surfaces 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 part”. 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%.

  In the configuration shown in FIG. 3, the reaction preventing film 50 is formed from the inside of the power generating element part A (that is, the portion between the solid electrolyte film 40 and the air electrode 60) (= in the solid electrolyte film 40). It extends to the outside of the power generation element part A so as to cover the surface of the part formed outside the power generation element part A) (so as to be in contact with the surface). The air electrode current collecting film 70 covers the surface of the reaction preventing film 50 (more specifically, the portion formed outside the power generating element part A in the reaction preventing film 50) (so as to be in contact with the surface). Is formed. In other words, the reaction preventing film 50 (more specifically, the part formed outside the power generation element part A in the reaction preventing film 50) in all the parts where the air electrode current collecting film 70 and the solid electrolyte film 40 face each other. Is intervening.

  As shown in FIGS. 1, 2, and 6, one end portion in the longitudinal direction of the support substrate 10 (end portion in the negative x-axis direction) is the one end in the longitudinal direction on the front and back main surfaces of the support substrate 10. A front-back connection member 80 that electrically connects the power generation element portions A provided on the side (x-axis negative direction side) is provided.

The front-back connection member 80 is made of, for example, the same material as the air electrode current collector film 70, that is, LSCF = (La, Sr) (Co, Fe) O ₃ (lanthanum strontium cobalt ferrite), LSC = (La, Sr) CoO. ₃ (lanthanum strontium cobaltite) or La (Ni, Fe, Cu) O ₃ or the like. In this case, the front-back connection member 80 is a fired body made of a perovskite-type conductive ceramic containing strontium (Sr) or lanthanum (La). The porosity of the front / back connection member 80 may be the same as or different from the porosity of the air electrode current collector film 70.

  As shown in FIG. 6, in this example, the front-back connection member 80 is provided so as to circulate around one end of the support substrate 10 in the longitudinal direction. Therefore, the front-back connection member 80 is provided so as to cover the surface of the “part covering the side end surface of the support substrate 10” (that is, the solid electrolyte membrane 40) in the “dense membrane”.

  In this example, the reaction preventing film 50 of the power generating element part A electrically connected by the front-to-back connection member 80 faces the front-back connection member 80 and the “dense film” (that is, the solid electrolyte film 40). It extends to the outside of the power generation element part A so as to be interposed in all parts. In other words, at one end in the longitudinal direction of the support substrate 10, the reaction is prevented so as to cover the surface of the “dense membrane” (solid electrolyte membrane 40) formed so as to cover the main surface and side end surfaces of the support substrate 10. A film 50 is formed, and a front-back connection member 80 is formed so as to cover the surface of the reaction preventing film 50.

  In the example shown in FIGS. 2 and 6, the front-back connection member 80 includes the air electrode 60 of the power generation element portion A formed on one of the upper and lower surfaces of the support substrate 10 (upper main surface in FIG. 2), and the support substrate. The fuel electrode 20 of the power generation element portion A formed on the other of the upper and lower surfaces (the lower main surface in FIG. 2) (more specifically, the interconnector 30 electrically connected to the fuel electrode 20). And are electrically connected. That is, the front-back connection member 80 electrically connects the power generation element portions provided on the upper and lower surfaces of the support substrate 10 in series.

As described above, as shown in FIG. 7, 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. 8, current flows as indicated by an arrow in each pair of adjacent power generation element portions A and A. As a result, as shown in FIG. 7, the entire SOFC (specifically, the interconnector 30 of the power generating element portion A on the front side in FIG. 7 and the air electrode 60 of the power generating element portion A on the farthest side in FIG. Power).

(Production method)
Next, an example of a method for manufacturing the “horizontal stripe type” SOFC shown in FIG. 1 will be briefly described with reference to FIGS. 9 to 17, “g” at the end of the reference numeral of each member represents that the member is “before firing”.

  First, a support substrate molded body 10g having the shape shown in FIG. 9 is produced. The molded body 10g of the support substrate is manufactured 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, CSZ). obtain. Hereinafter, the description will be continued with reference to FIGS. 10 to 17 showing partial cross sections corresponding to line 10-10 shown in FIG. 9.

  When the support substrate molded body 10g is manufactured as shown in FIG. 10, next, as shown in FIG. 11, fuel electrode current collectors are formed in the recesses formed on the upper and lower surfaces of the support substrate molded body 10g. Each of the molded parts 21g is embedded and formed. Next, as shown in FIG. 12, a molded body 22g of the fuel electrode active portion is embedded and formed in each recess formed in 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 each of the fuel electrode active parts 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), It is embedded and formed using printing methods.

Subsequently, as shown in FIG. 13, in each recess formed in “a portion excluding the portion where the molded body 22 g of the fuel electrode active portion is embedded” on the outer surface of the molded body 21 g of each fuel electrode current collector. The interconnector molded bodies 30g are respectively embedded and formed. The molded body 30g of each interconnector is embedded and formed by 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, as shown in FIG. 14, the outer periphery extending in the longitudinal direction of the molded body 10g of the support substrate in a state where the molded body (21g + 22g) of the plurality of fuel electrodes and the molded body 30g of the plurality of interconnectors are respectively embedded and formed. A solid electrolyte membrane molding film 40g is formed on the entire surface excluding the central portion of each portion where the plurality of interconnector moldings 30g are formed on the surfaces (ie, the upper and lower main surfaces and the side end surfaces on both sides). Is done. The molded membrane 40g of the solid electrolyte membrane is formed using, for example, a printing method, a dipping method, etc., 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). The

  Next, as shown in FIG. 15, a reaction preventing film forming film 50 g is formed on the entire outer surface of the solid electrolyte film forming body 40 g. The molded film 50g of each reaction preventing film is formed using a slurry obtained by adding a binder or the like to the powder of the material (for example, GDC) of the reaction preventing film 50, 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 in air at 1500 ° C. for 3 hours. As a result, a structure in which the air electrode 60 and the air electrode current collector film 70 are not formed in the SOFC shown in FIG. 1 is obtained. Hereinafter, the laminated fired body at this stage is referred to as an “intermediate fired body”.

  Next, as shown in FIG. 16, an air electrode forming film 60 g is formed on the outer surface of each reaction preventing film 50. The molded film 60g 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, as shown in FIG. 17, for each pair of adjacent power generation element portions, air is formed so as to straddle the air electrode forming film 60 g of one power generation element portion and the interconnector 30 of the other power generation element portion. On the outer surface of the electrode forming film 60 g, the solid electrolyte film 40, and the interconnector 30, the air electrode current collecting film forming film 70 g is formed. The molded film 70g of each air electrode current collector film is, for example, 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, La (Ni, Fe, Cu) O ₃ ). Is formed using a printing method or the like.

Further, a molding film of the front-back connection member is formed so as to go around the periphery of one end of the support substrate 10 in the longitudinal direction (see FIGS. 2 and 6). For example, the molded film of the front-back connection member is made of 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, La (Ni, Fe, Cu) O ₃ ). It is formed using a printing method or the like.

  And the support substrate 10 in the state in which the molded films 60g and 70g and the molded film of the front-back connection member are thus formed is baked in air at 1050 ° C. for 3 hours. Thereby, the SOFC shown in FIG. 1 is obtained. At this point, the Ni component in the fuel electrode 20 (current collector 21 + active portion 22) is NiO due to firing in an oxygen-containing atmosphere. Therefore, in order to acquire the electron conductivity of the fuel electrode 20 (current collector 21 + active part 22), a reducing fuel gas is then flowed from the support substrate 10 side, and NiO is heated at 800 to 1000 ° C. for 1 to 10 hours. The reduction treatment is performed over a period of time. This reduction process may be performed during power generation. In the above, an example of the manufacturing method of SOFC shown in FIG. 1 was demonstrated.

(Action / Effect)
Hereinafter, the operation and effect of this embodiment will be described. As shown in FIGS. 2 and 18, for each of the front and back surfaces of the support substrate 10, the end portion on the fuel gas discharge side in the longitudinal direction (x-axis direction) of the support substrate 10 (the discharge side end portion of the support substrate). The power generation element portion A that is closest to is particularly referred to as an “end power generation element portion As”. In addition, as shown in FIG. 2, a plurality of air electrode current collector films 70 (a plurality of portions that electrically connect the power generating element portions A adjacent in the longitudinal direction) constituting a part of the “electrical connection portion”. Among them, the air electrode current collector film 70 that electrically connects the “end power generation element portion As” and the “power generation element portion A adjacent to the end power generation element portion As”, This is referred to as “electrofilm 70s”.

  In the said embodiment, as shown in FIG.2 and FIG.18, about each of the electric power generation element part A in a longitudinal direction about each of the front and back of the support substrate 10, several (this example) other than the edge part electric power generation element part As. Then, the areas S1 of the three power generation element portions A are equal, and the area S2 of the end power generation element portion As is larger than the area S1. In this example, the length in the width direction (y-axis direction) of the end power generation element portion As is equal to the length in the width direction of the power generation element portions A other than the end power generation element portion As, while the end power generation element portion As. Since the length in the longitudinal direction (x-axis direction) is larger than the length in the longitudinal direction of the power generation element portion A other than the end power generation element portion As, the area S2 is larger than the area S1. In the above embodiment, as shown in FIGS. 2 and 18, the positions in the longitudinal direction of the plurality (four) power generation element portions A on the front side of the support substrate 10 correspond to the back side of the support substrate 10. Each of the power generation element portions A coincides with the position in the longitudinal direction. Here, the “position in the longitudinal direction of the power generation element portion A” refers to an end portion on the fuel gas discharge side in the longitudinal direction in which the power generation element portion A is located (occupied) (hereinafter referred to as the present specification). The same).

  For example, “the areas of the respective power generation element portions A located at both ends in the longitudinal direction of the plurality of power generation element portions A in the longitudinal direction” are described in the configuration according to the above embodiment and the above-mentioned Patent Document 2. A case is assumed where the areas of the plurality of power generation element portions are equal in “a configuration in which the areas sequentially increase along the flow direction of the fuel gas”. In this case, as compared with the configuration described in Patent Document 2, the configuration according to the above embodiment can increase the number of the plurality of power generation element portions in the longitudinal direction. Specifically, for example, in the above-described embodiment, four power generation element portions A are formed in the longitudinal direction. However, in the configuration described in Patent Document 2, only three or less power generation element portions A are formed in the longitudinal direction. There is a high possibility that it cannot be formed.

  In addition, the first and second problems described in the “Summary of the Invention” section are substantially generated in the end power generation element portion As, and other “support substrate discharge” It does not occur remarkably in the power generation element portion A ”near the side end portion. Therefore, it is considered that the first and second problems can hardly occur by increasing the area of only the end power generation element portion As and reducing the current density of only the end power generation element portion As. . As described above, according to the embodiment, it is possible to provide a device in which the first and second problems are unlikely to occur and the “number of the plurality of power generation element portions in the longitudinal direction” is large.

In addition, in the above embodiment, only the area of the end power generation element portion As is large,
Of the plurality of air electrode current collector films 70 (a plurality of portions electrically connecting the power generating element portions A adjacent in the longitudinal direction) constituting a part of the “electrical connection part”, the end air electrode current collectors The length in the longitudinal direction (x-axis direction) of only the membrane 70s is longer than the length in the longitudinal direction of the remaining air electrode current collector membrane 70. In other words, the resistance of only the end air electrode current collector film 70s tends to be larger than the resistance of the remaining air electrode current collector films 70. In this regard, according to the above-described embodiment, as shown in FIG. 2, the cross-sectional area of the end air electrode current collector film 70 s (in the direction (yz plane direction) perpendicular to the direction in which electricity flows (longitudinal direction)). The cross-sectional area) is larger than the cross-sectional area of the remaining air electrode current collector film 70. Accordingly, the resistance of the end air electrode current collector film 70s can be reduced. As a result, the power generation efficiency of the SOFC as a whole can be increased.

(Optimal ratio of areas S1, S2)
The present inventor has found that the SOFC limit fuel utilization rate has a strong correlation with the value “S2 / S1” in the SOFC according to the above embodiment. Hereinafter, test A in which this has been confirmed will be described.

<Test A>
In this test A, for the SOFC shown in FIG. 1 (and FIG. 2 and FIG. 18), the combination of the area S1 (mm ² ) and the area S2 (mm ² ), and thus the value “S2 / S1”. Several samples with different values were produced. Specifically, as shown in Table 1, seven kinds of levels (combinations) were prepared. Ten samples (N = 10) were made for each level.

  Each sample (SOFC shown in FIGS. 1, 2, and 18) was produced by the same procedure as in the above embodiment. That is, first, a laminate (green body) composed of the support substrate 10, the fuel electrode 20 (the current collector 21 + the active part 22), the interconnector 30, the solid electrolyte film 40, and the reaction prevention film 50 is co-fired, An “intermediate fired body” was produced. The air electrode 60 and the air electrode current collector film 70 (green body) were formed on the “intermediate fired body”, and the air electrode 60 and the air electrode current collector film 70 (green body) were fired. The reduction treatment described above was applied to this fired body, and each sample was obtained.

For each sample, MgO—Y ₂ O ₃ , NiO / Ni—MgO—Y ₂ O ₃ , MgO—MgAl ₂ O ₄ , NiO / Ni—MgO—MgAl ₂ O _4, etc. are used as the material of the support substrate 10. It was done. NiO / Ni—YSZ, NiO / Ni—CSZ, NiO / Ni—Y ₂ O ₃ or the like was used as a material for the fuel electrode current collector 21 and the fuel electrode active part 22. As a material of the interconnector 30, LaCrO ₃ was adopted. As the material of the solid electrolyte membrane 40, YSZ (8YSZ) was adopted. As a material of the reaction preventing film 50, GDC = (Ce, Gd) O ₂ , SDC = (Ce, Sm) O ₂ or the like was adopted. As a material of the air electrode current collector film 70, LSCF = (La, Sr) (Co, Fe) O ₃ , LSC = (La, Sr) CoO ₃ , La (Ni, Fe, Cu) O ₃ or the like is adopted. It was.

  The length of each sample in the longitudinal direction (x-axis direction) was 50 to 500 mm, the length in the width direction (y-axis direction) was 10 to 100 mm, and the thickness (z-axis direction) was 1 to 5 mm. . The shape of the air electrode current collector film 70 excluding the end air electrode current collector film 70s as viewed from above (z-axis direction) is 10 to 40 mm in the longitudinal direction (x-axis direction), and the width direction (y-axis direction). ) Was a rectangle having a length of 5 to 80 mm. The shape of the end air electrode current collector film 70s as viewed from above (z-axis direction) is 10 to 80 mm in the longitudinal direction (x-axis direction) and 5 to 80 mm in the width direction (y-axis direction). It was a rectangle. The thickness of the air electrode current collector film 70 excluding the end air electrode current collector film 70 s was 50 to 500 μm. The thickness of the end air electrode current collector film 70 s was 80 to 600 μm.

  For each sample, the front and back area S1 and the front and back area S2 of the support substrate 10 were the same. Further, the longitudinal positions of the plurality of (four) power generation element portions A on the front side of the support substrate 10 were respectively matched with the corresponding longitudinal positions of the power generation element portions A on the back side of the support substrate 10. For each of the front and back surfaces of the support substrate 10, the shape of the power generation element portion A excluding the end power generation element portion As viewed from above (z-axis direction) has a length in the longitudinal direction (x-axis direction) of 10 to 35 mm and a width. The length of the direction (y-axis direction) was a rectangle of 5 to 80 mm. The shape of the end power generation element portion As viewed from above (z-axis direction) is a rectangle having a length in the longitudinal direction (x-axis direction) of 10 to 45 mm and a length in the width direction (y-axis direction) of 5 to 80 mm. Met. The length in the width direction (y-axis direction) of the end power generation element portion As was equal to the length in the width direction of the power generation element portions A other than the end power generation element portion As. Therefore, the value “S2” is adjusted by adjusting the ratio between the length in the longitudinal direction (x-axis direction) of the end power generation element portion As and the length in the longitudinal direction of the power generation element portions A other than the end power generation element portion As. / S1 "has been adjusted.

In this test A, the limit fuel utilization rate of SOFC was measured for each sample after the reduction treatment (SOFC shown in FIGS. 1, 2, and 18). This measurement was performed under the conditions that the temperature was 750 ° C. and the current density of the current flowing through the power generation element portion A other than the end power generation element portion As was 0.25 A / cm ² . The results of this measurement are as shown in Table 1.

  As can be understood from Table 1, when the value “S2 / S1” is less than 1.0, the limit fuel utilization rate of SOFC is greatly reduced, and the value “S2 / S1” is 1.0 or more and less than 1.1. In this case, the limit fuel utilization rate of the SOFC is slightly reduced, while if the value “S2 / S1” is 1.1 or more, the limit fuel utilization rate of the SOFC becomes good. Thus, when the value “S2 / S1” is small, the limit fuel utilization rate of the SOFC decreases because when the value “S2 / S1” is small, the current density of the current flowing through the end power generation element portion As is relative. This is considered to be due to the fact that the “first problem” described above (see the summary of the invention) is likely to occur in the end power generation element portion As.

  From the above, it can be said that when the value “S2 / S1” is 1.1 or more, the SOFC limit fuel utilization rate can be maintained better than in the case where the value is not so.

  By the way, in the SOFC according to the above-described embodiment, when operated in a normal environment, the end power generation element portion As is peeled (particularly, peeling at the interface between the support substrate 10 and the fuel electrode current collector 21). Does not occur. However, when this SOFC is operated under a severe environment in terms of thermal stress, peeling of the end power generation element portion As may occur. The present inventor has found that the presence or absence of such peeling of the end power generation element portion As has a strong correlation with the value “S2 / S1”. Hereinafter, test B in which this has been confirmed will be described.

<Test B>
In this test B as well as the above test A, for the SOFC shown in FIG. 1 (and FIG. 2 and FIG. 18), the combination of area S1 (mm ² ) and area S2 (mm ² ), and therefore A plurality of samples having different values “S2 / S1” were produced. Specifically, as shown in Table 2, eight levels (combinations) were prepared. Ten samples (N = 10) were made for each level.

  The production procedure of each sample (SOFC shown in FIGS. 1, 2 and 18) and the specifications of each sample (shape, size, material, etc. of each component) are used in Test A above. It was the same as the sample.

  In this test, for each sample, “reducing fuel gas was passed through the fuel electrode 20 and air was passed through the air electrode 60 while raising the ambient temperature from room temperature to 750 ° C. in 2 hours and 30 minutes. Is constant at 750 ° C., a constant current is supplied to the SOFC using a constant current generator (ie, the SOFC is operated (power generation)), and then the supply of fuel gas and air is stopped (ie, the SOFC The so-called “shutdown test” was repeated 10 times, with the pattern of “decreasing the ambient temperature from 750 ° C. to room temperature in 4 hours” with “one cycle” in a state where the operation of the system was stopped). And about each sample, the presence or absence of generation | occurrence | production of peeling of the edge part electric power generation element part As was confirmed. This confirmation was made by visual observation as well as observation using a microscope. The results are as shown in Table 2.

  As can be understood from Table 2, when the value “S2 / S1” is larger than 2.2, the end power generation element portion As is peeled off as compared with the case where the value “S2 / S1” is 2.2 or less. Easy to do. This is considered based on the following reasons. That is, in the above-described cut-down test, the support substrate 10 and the fuel electrode 20 are exposed to the reducing atmosphere in a state where the reducing fuel gas is supplied to the fuel electrode 20, while the supply of the fuel gas is stopped. In the state, it can be exposed to an oxidizing atmosphere. For this reason, the support substrate 10 and the fuel electrode 20 undergo dimensional changes due to Ni oxidation / reduction. Between the support substrate 10 and the fuel electrode 20, there is a difference in the rate of dimensional change caused by Ni oxidation / reduction. In addition, in the cut-down test, the ambient temperature of the support substrate 10 and the fuel electrode 20 varies greatly. For this reason, a dimensional change due to thermal strain occurs in the support substrate 10 and the fuel electrode 20. There is a difference in the rate of dimensional change caused by thermal strain between the support substrate 10 and the fuel electrode 20. From the above, at the interface between the support substrate 10 and the fuel electrode current collector 21, there may be a difference in the amount of dimensional change between both due to oxidation / reduction and thermal strain. Here, when the value “S2 / S1” is large, the area of the interface between the fuel electrode current collector 21 and the support substrate 10 of the end power generation element portion As is relatively large, and thus the end power generation element portion As of The difference in the amount of dimensional change between the fuel electrode current collector 21 and the support substrate 10 due to oxidation / reduction and thermal strain increases. As a result, it is considered that separation of the end power generation element portion As (especially, separation at the interface between the support substrate 10 and the fuel electrode current collector 21) is likely to occur.

  From the above, when the value “S2 / S1” is 2.2 or less, compared with the case where the value is not so, separation of the end power generation element portion As (particularly at the interface between the support substrate 10 and the fuel electrode current collector 21). It can be said that the detachment of the film is difficult to occur. As described above, from the results of tests A and B, when the value “S2 / S1” is 1.1 to 2.2, the limit fuel utilization rate of the SOFC is good and the end portion is compared to the case where the value is not so. It can be said that exfoliation of the power generation element portion As hardly occurs.

  In addition, the present inventor has values when the above embodiment is used under normal conditions and environment (for example, a pattern in which the temperature is raised from room temperature to 750 ° C. in 4 hours and then lowered from 750 ° C. to room temperature in 12 hours). It has been separately confirmed that even when “S2 / S1” is larger than 2.2, the above-described end power generation element portion As does not peel off.

  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 FIGS. 2 and 18, for each of the front and back sides of the support substrate 10, a plurality of power generation element portions A (a plurality of power generation element portions A (area S <b> 1) and end portions in the longitudinal direction) The power generation element portion As (area S2)) is formed, but as shown in FIGS. 19 and 20, a plurality of power generation element portions A (a plurality of power generation elements A in the longitudinal direction are provided only on one side of the front and back of the support substrate 10. The element part A (area S1) and the end power generation element part As (area S2)) may be formed. Also in this case, as in the above-described embodiment, when the value “S2 / S1” is 1.1 to 2.2, the limit fuel utilization rate of the SOFC is good and the end portion is compared to the case where the value is not so. It has been found that peeling of the power generating element portion As hardly occurs.

  Moreover, in the said embodiment, as shown in FIG.2 and FIG.18, the position of the longitudinal direction of several (4) electric power generation element part A of the front side of the support substrate 10 respond | corresponds on the back side of the support substrate 10. FIG. Although it corresponds with the position of the longitudinal direction of the electric power generation element part A respectively, as shown in FIG.21 and FIG.22, the position of the longitudinal direction of several (4) electric power generation element part A of the front side of the support substrate 10 is shown. However, they may be shifted to the same longitudinal side with respect to the longitudinal position of the corresponding power generation element portion A on the back side of the support substrate 10. In the example shown in FIGS. 21 and 22, the longitudinal positions of the (four) power generation element portions A on the front side of the support substrate 10 are the longitudinal directions of the corresponding power generation element portions A on the back side of the support substrate 10. Are shifted to the fuel gas discharge side in the longitudinal direction. That is, the end power generation element portion As on the front side of the support substrate 10 is arranged on the fuel gas discharge side in the longitudinal direction as compared with the end power generation element portion As on the back side of the support substrate 10.

  In the example shown in FIG. 21 and FIG. 22, the area S2 of the front-side end power generation element portion As of the support substrate 10 has a plurality of power generation element portions A other than the front-end end power generation element portion As of the support substrate 10. The area S2 ′ of the end power generation element portion As on the back side of the support substrate 10 is larger than the area S1, and is larger than the areas S1 of the plurality of power generation element portions A other than the end power generation element portion As on the back side of the support substrate 10, and It is preferable that the area is smaller than the area S2 of the end power generation element portion As on the front side of the support substrate 10. The front and back areas S1 of the support substrate 10 may be the same or different.

  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.

  In addition, in the above-described embodiment, the support substrate 10 has a “flat shape having a longitudinal direction”, but the support substrate may have a “cylindrical shape having a longitudinal direction”.

  DESCRIPTION OF SYMBOLS 10 ... Support substrate, 12 ... Recess, 20 ... Fuel electrode, 21 ... Fuel electrode current collector, 21a, 21b ... Recess, 22 ... Fuel electrode active part, 30 ... Interconnector, 40 ... Solid electrolyte membrane, 50 ... Reaction prevention Membrane, 60 ... Air electrode, 70 ... Air electrode current collector film, 70s ... End air electrode current collector film, A ... Power generation element part, As ... End power generation element part

Claims (2)

A support substrate having a longitudinal direction and having a gas flow path formed therein along the longitudinal direction;
A plurality of power generating element portions each provided at a plurality of locations separated from each other along the longitudinal direction on the surface of the support substrate, each of which is formed by laminating at least a fuel electrode, a solid electrolyte membrane, and an air electrode;
An electrical connection portion that electrically connects one fuel electrode and the other air electrode of the adjacent power generation element portions;
A fuel cell comprising:
Among the plurality of power generation element portions, the remaining plurality other than the end power generation element portion which is the power generation element portion closest to the end portion on the discharge side of the fuel gas flowing in the gas flow path in the longitudinal direction of the support substrate The areas contributing to the power generation of the power generation element part are first areas, and the area contributing to the power generation of the end power generation element part is a second area larger than the first area,
The cross-sectional area of the portion that electrically connects the end power generation element portion and the power generation element portion adjacent to the end power generation element portion in the electrical connection portion is the end power generation element in the electrical connection portion. A fuel cell having a larger cross-sectional area than a portion that electrically connects adjacent power generating element portions other than the portion. The fuel cell according to claim 1 , wherein
The support substrate has a flat plate shape,
The plurality of power generation element portions and the electrical connection portions are respectively provided on the main surfaces of the front and back surfaces of the support substrate,
The end power generation element portion on one side of the front and back sides of the support substrate is disposed on the fuel gas discharge side in the longitudinal direction as compared to the end power generation element portion on the other side of the front and back sides of the support substrate,
About the plurality of power generation element portions on the one side of the front and back of the support substrate,
The areas contributing to power generation of the remaining plurality of power generation element parts other than the end power generation element parts are each the first area, and the area contributing to power generation of the end power generation element parts is larger than the first area. The second area,
About the plurality of power generation element portions on the other side of the front and back of the support substrate,
The areas contributing to power generation of the remaining plurality of power generation element parts other than the end power generation element parts are each third areas, the area contributing to power generation of the end power generation element parts is larger than the third area, and A fuel cell having a fourth area smaller than the second area.

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