Fuel cell and method for manufacturing fuel cell

Abstract

The present invention provides fuel cells which constitute a fuel cell stack by being stacked upon each other, with separators being interposed therebetween. Each of the fuel cells is configured by sequentially superposing, on a metal support that is arranged on a separator, an anode layer, a solid electrolyte layer and a cathode layer; the metal support and the anode layer are formed of a porous metal; and at least one of the metal support and the anode layer is internally provided with a reforming catalyst. A heat transfer suppression layer, which suppresses heat transfer from the separator to the metal support, is formed between the metal support and the separator, while being bonded to the separator at least in a portion where the metal support and the separator are bonded to each other.

Description

[Technical field]

[0001] The present invention relates to a fuel cell and a method for manufacturing a fuel cell. [Background technology]

[0002] JP2005-294152A discloses a solid oxide fuel cell (SOFC) cell that is stacked with a separator interposed therebetween. In this SOFC cell, a fuel electrode current collector is disposed on the outside of an anode layer, and a separator is disposed on the outside of the fuel electrode current collector. A porous metal body carrying a reforming catalyst is disposed between the separator and the fuel electrode current collector. This allows reforming of fuel gas (internal reforming) to occur inside the SOFC cell. Summary of the Invention

[0003] In JP2005-294152A, the reforming catalyst is supported on a metal body with high thermal conductivity and disposed between the separator and the fuel electrode current collector, so the reforming catalyst is easily affected by heat from the separator. In particular, when laser welding or the like is performed to strengthen the bond between the separator and the metal body, the heat required for bonding may cause sintering of the reforming catalyst in the metal body, which may result in a decrease in power generation efficiency.

[0004] In view of the above problems, an object of the present invention is to provide a fuel cell that prevents sintering of the reforming catalyst and has good power generation efficiency.

[0005] According to one aspect of the present invention, there is provided a fuel cell that is stacked via a separator to form a fuel cell stack. The fuel cell is configured by stacking an anode layer, a solid electrolyte layer, and a cathode layer in this order on a metal support on a separator, the metal support and the anode layer being made of porous metal, and a reforming catalyst being formed inside at least one of the metal support and the anode layer. Between the metal support and the separator, at least at the site where the metal support and the separator are joined, a heat conduction suppression layer is formed that is joined to the separator and suppresses heat conduction from the separator to the metal support. [Brief description of the drawings]

[0006] [Figure 1] FIG. 1 is a schematic diagram of a fuel cell according to a first embodiment. [Diagram 2] FIG. 2 is a schematic diagram illustrating the stack structure of the fuel cell. [Diagram 3] FIG. 3 is a flow chart illustrating the manufacturing process of the fuel cell. [Figure 4] FIG. 4 is a schematic diagram of a fuel cell according to the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0007] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0008] (First embodiment) 1 is a schematic diagram of a fuel cell 100 according to a first embodiment. The fuel cell 100 is a solid oxide fuel cell (SOFC) that receives anode gas and cathode gas to generate power. A plurality of fuel cells 100 are stacked to form a fuel cell stack, and plate-shaped separators 10 are provided between adjacent fuel cells 100.

[0009] A fuel cell stack formed by stacking the fuel cell units 100 is intended to be mounted on a mobile vehicle such as an electric vehicle or a hybrid vehicle, but may also be used as a power source for various electrical devices.

[0010] As shown in FIG. 1, a fuel cell 100 includes a solid electrolyte layer 20, a cathode layer 30 disposed on one side of the solid electrolyte layer 20, an anode layer 40 disposed on the other side of the solid electrolyte layer 20, and a metal support 50 provided to support the anode layer 40.

[0011] The solid electrolyte layer 20 is a thin film formed of an oxide having oxygen ion conductivity, and is sandwiched between the anode electrode layer 40 and the cathode electrode layer 30. As the oxide, for example, yttria-stabilized zirconia (YSZ), scandium-stabilized zirconia (SSZ), samarium-doped ceria (SDC), gadolinium-doped ceria (GDC), lanthanum strontium magnesium gallate (LSGM), etc. can be used.

[0012] The cathode layer 30 is a plate-shaped member formed of, for example, lanthanum strontium cobalt composite oxide (LSC), lanthanum strontium cobalt iron oxide (LSCF), or the like, and is provided so as to be in contact with the upper surface of the solid electrolyte layer 20. In the cathode layer 30, a reduction reaction occurs that reduces oxygen in the cathode gas (air).

[0013] The anode layer 40 is a porous metal plate member formed of a metal such as nickel (Ni) and an oxide such as yttria-stabilized zirconia (YSZ). The anode layer 40 is provided in contact with the lower surface of the solid electrolyte layer 20 and placed on a metal support 50. In the anode layer 40, an oxidation reaction occurs in which the oxide ions conducted through the solid electrolyte layer 20 oxidize the anode gas containing hydrogen and the like. The fuel cell 100 generates power based on the electrode reaction in the cathode layer 30 and the anode layer 40.

[0014] The metal support 50 is a porous plate-like member formed of a metal such as stainless steel, iron (Fe), or nickel (Ni). The metal support 50 is provided to support the anode layer 40, and functions as a structural member for reinforcing the strength of the fuel cell 100. In this manner, the fuel cell 100 is configured as a so-called metal-supported fuel cell in which the anode layer 40, solid electrolyte layer 20, and cathode layer 30 are laminated in this order on the metal support 50 as a support.

[0015] A reforming catalyst that reforms a raw fuel containing a hydrocarbon into an anode gas mainly composed of hydrogen is formed inside the anode layer 40 and the metal support 50. The raw fuel containing a hydrocarbon is supplied from a fuel flow passage 15 (described later) through the metal support 50 to the anode layer 40, and during the supply process, the raw fuel is reformed into an anode gas mainly composed of hydrogen by the reforming catalyst in the metal support 50 and the anode layer 40. In other words, the fuel cell 100 is an internal reforming type fuel cell.

[0016] The separator 10 is a plate-like member provided between adjacent fuel cell cells 100 in the stacked fuel cell cells 100. The material forming the separator 10 is not particularly limited as long as it is an electrically conductive and thermally conductive material, and for example, an alloy or metal containing iron (Fe) or chromium (Cr) is used. The separator 10 is a plate-like member formed by press-molding the above-mentioned electrically conductive and thermally conductive material, and is electrically connected to the fuel cell cells 100.

[0017] The separator 10 has a first abutment portion 11 that abuts against the lower surface of one of two adjacent fuel cell cells 100, a second abutment portion 12 that abuts against the upper surface of the other fuel cell 100, and a connection portion 13 that connects the first abutment portion 11 and the second abutment portion 12.

[0018] The separator 10 is configured as an uneven member by connecting the first contact parts 11 and the second contact parts 12 arranged alternately (in order) in a predetermined direction (separator width direction) with the connecting parts 13. By having such an uneven structure, the separator 10 has a plurality of air flow paths 14 on one side surface and a plurality of fuel flow paths 15 on the other side surface. In FIG. 1, the connecting parts 13 are formed in a straight line and the fuel flow paths 15 are formed so that the front cross-sectional area of ​​the flow path is trapezoidal, but this is not necessarily limited to this. For example, the connecting parts 13 may be formed in a curved line and the fuel flow paths 15 may be configured so that the flow path cross-sectional area is curved. That is, the uneven shape referred to here includes a curved shape. In this way, since the separator 10 has an uneven (including curved) structure, even if the fuel cell 100 is displaced, the separator 10 can follow the displacement.

[0019] The first contact portion 11 of the separator 10 is formed as a flat surface and contacts the metal support 50 of one of the fuel cell cells 100 via a heat conduction suppressing layer 60 described below. The separator 10 is fixed to the one of the fuel cell cells 100, for example, by welding the first contact portion 11 and the heat conduction suppressing layer 60.

[0020] The second contact portion 12 of the separator 10 is formed as a flat surface and contacts the cathode layer 30 of the other fuel cell 100. The separator 10 is fixed to the other fuel cell 100, for example, by welding the second contact portion 12 and a part of the cathode layer 30.

[0021] The connecting portion 13 of the separator 10 is formed as a wall portion connecting an end portion of the first contact portion 11 and an end portion of the second contact portion 12. The space formed by the connecting portion 13, the second contact portion 12, and the metal support 50 becomes a fuel flow path 15 for supplying fuel to the anode layer 40. On the other hand, the space formed by the connecting portion 13, the first contact portion 11, and the cathode layer 30 becomes an air flow path 14 for supplying oxygen to the cathode layer 30.

[0022] In the fuel cell 100 configured as described above, fuel is supplied from the fuel flow path 15 to the anode layer 40 via the metal support 50 connected to the separator 10, and the fuel is reformed by the reforming catalyst formed inside the metal support 50 and the anode layer 40.

[0023] Incidentally, the porous metal constituting the metal support 50 has high thermal conductivity, and when the metal support 50 and the separator 10 are in contact with each other, the reforming catalyst inside the metal support 50 is easily affected by heat from the separator 10. In particular, when the separator 10 and the metal support 50 are joined by laser welding, the heat required for joining may cause sintering of the reforming catalyst inside the metal support 50, resulting in a decrease in power generation efficiency.

[0024] Therefore, in this embodiment, a heat conduction suppression layer 60 that suppresses heat conduction from the separator 10 to the metal support 50 is provided between the metal support 50 and the separator 10. This increases the distance from the separator 10 to the metal support 50, and reduces the effect of heat conducted from the separator 10 to the metal support 50. This prevents sintering of the reforming catalyst inside the metal support 50, and suppresses a decrease in power generation efficiency.

[0025] The heat conduction suppressing layer 60 will be described in detail below.

[0026] The thermal conduction suppression layer 60 is made of, for example, the same material as the metal support 50, and is formed between the first contact portion 11 of the separator 10 that contacts the lower surface of the fuel cell 100 and the metal support 50, as shown in FIG. 1. By forming the thermal conduction suppression layer 60 between the separator 10 and the metal support 50, the distance from the separator 10 to the metal support 50 becomes longer, and the reforming catalyst inside the metal support 50 becomes less susceptible to the influence of heat from the separator 10 and the interface between the separator 10 and the thermal conduction suppression layer 60 (hereinafter referred to as heat from the separator 10). Furthermore, by making the thermal conduction suppression layer 60 out of the same material as the metal support 50, the bond at the interface between the thermal conduction suppression layer 60 and the metal support 50 (current collecting bond on the anode side) becomes stronger, improving power generation performance.

[0027] FIG. 2 is a schematic diagram illustrating the layered structure of the fuel cell 100, and is a cross-sectional view taken along line AA in FIG.

[0028] As described above, the thermal conduction suppression layer 60 is formed between the first contact portion 11 of the separator 10 and the metal support 50. The thermal conduction suppression layer 60 is a porous metal body made of the same material as the metal support 50, but the thermal conduction suppression layer 60 is configured to have a larger porosity than the metal support 50. For this reason, the thermal conduction area of ​​the thermal conduction suppression layer 60 is smaller than that of the metal support 50, and heat from the separator 10, such as welding heat, is less likely to be transmitted to the metal support 50. Therefore, the reforming catalyst in the metal support 50 is more effectively prevented from being affected by heat, and sintering and the like are more reliably prevented.

[0029] The thermal conduction suppression layer 60 also supports a material having a lower thermal conductivity than the material constituting the metal support 50, such as an oxide of cerium (Ce), zirconium (Zr), aluminum (Al), barium (Ba), or yttrium (Y). This makes the thermal conductivity of the thermal conduction suppression layer 60 lower than that of the metal support 50, making it difficult for the metal support 50 to transmit heat from the separator 10. This further suppresses the reforming catalyst in the metal support 50 from being affected by heat, and more reliably prevents sintering and the like. The anode layer 40 may also support the oxides having a low thermal conductivity as described above.

[0030] Moreover, the separator 10 is fixed to one of the fuel cell cells 100 by welding the first contact portion 11 and the heat conduction suppression layer 60, and the weld bead 16 formed by this welding is formed from the separator 10 to the heat conduction suppression layer 60. As shown in FIG. 2, the vicinity of the weld bead 16 is covered by the heat conduction suppression layer 60, and the weld bead 16 is formed only in the heat conduction suppression layer 60 and does not extend into the inside of the metal support 50. The weld bead 16 serves as a heat conduction path for transmitting heat from the separator 10, but in this embodiment, since the heat conduction suppression layer 60 is formed in the vicinity of the portion where the weld bead 16 is generated, the heat from the separator 10 is less likely to be transmitted to the metal support 50. Therefore, the reforming catalyst in the metal support 50 is less likely to be affected by the heat from the separator 10, and sintering and the like are prevented. Furthermore, if the weld beads 16 were formed up to the inside of the metal support 50, heat from the separator 10 would be easily conducted to the metal support 50, but in this embodiment, the weld beads 16 are formed only within the heat conduction suppression layer 60. Therefore, heat from the separator 10 is less likely to be conducted to the reforming catalyst in the metal support 50, and sintering and the like are prevented.

[0031] Next, the manufacturing process of the fuel cell 100 will be described.

[0032] Fig. 3 is a flow chart illustrating the manufacturing process of the fuel cell 100. As shown in Fig. 3, the manufacturing process of the fuel cell 100 includes a lamination step (S10), a sintering step (S20), a catalyst formation step (S30), and a bonding step (S40).

[0033] In the lamination step (S10), an anode layer 40, a solid electrolyte layer 20, and a cathode layer 30, all made of porous metal, are laminated in this order on a metal support 50 made of porous metal. At this time, each layer may be bonded together by a method such as roll pressing.

[0034] In the sintering step (S20), the heat conduction suppression layer 60 made of porous metal is integrated with the metal support 50, anode layer 40, solid electrolyte layer 20, and cathode layer 30 laminated in the lamination step (S10) by co-sintering from the lower surface side of the metal support 50 to form a laminate. By co-sintering the heat conduction suppression layer 60 with the metal support 50, anode layer 40, solid electrolyte layer 20, and cathode layer 30 in this manner, the bonding between the layers can be strengthened compared to when each layer is sintered separately, and the manufacturing process can be simplified.

[0035] As described above, since the thermal conduction suppression layer 60 and the metal support 50 are made of the same material, the interface between the thermal conduction suppression layer 60 and the metal support 50 is firmly bonded by co-sintering. That is, the current collecting bond on the anode side is strengthened, and the power generation performance of the fuel cell 100 is improved.

[0036] After forming the laminate in the sintering step (S20), in the catalyst formation step (S30), a reforming catalyst is formed on the anode layer 40 and the metal support 50 by an impregnation method. Specifically, the catalyst formation step (S30) is performed as follows. First, a metal solution (catalyst solution) containing reforming catalyst materials such as nickel (Ni), platinum (Pt), rhodium (Rh), palladium (Pd), iridium (Ir), manganese (Mn), cobalt (Co), etc. is prepared. Next, the catalyst solution is dropped onto the laminate from the outside (anode side) of the metal support 50 to permeate the porous skeleton of the metal support 50 and the anode layer 40. Next, a heat treatment is performed to precipitate catalyst particles. As a result, a reforming catalyst is formed on the anode layer 40 and the metal support 50. By forming the reforming catalyst using the impregnation method in this way, the catalyst permeates into the inside of the porous metal, and the specific surface area of ​​the catalyst is increased, compared to when the catalyst is formed by a spray coating method or the like. Therefore, the catalytic activity is increased, and the catalytic performance is improved. The reforming catalyst can also be formed in the heat conduction suppression layer 60 made of a porous metal.

[0037] After the reforming catalyst is formed, in a bonding step (S40), the lower surface of the thermal conduction suppression layer 60 in the laminate consisting of the thermal conduction suppression layer 60, the metal support 50, the anode layer 40, the solid electrolyte layer 20, and the cathode layer 30 is bonded to the first contact portion 11 of the separator 10. The bonding to the separator 10 can be performed by laser welding or the like. At this time, heat from the laser welding is input to the laminate, but the thermal conduction suppression layer 60 suppresses the conduction of the welding heat to the metal support 50, and prevents the reforming catalyst in the metal support 50 from being sintered. Note that if a reforming catalyst is also formed in the thermal conduction suppression layer 60, the reforming catalyst in the thermal conduction suppression layer 60 may be sintered by the welding heat, but it is sufficient that no sintering occurs in the reforming catalyst in the metal support 50 and the anode layer 40.

[0038] As described above, the fuel cell 100 is manufactured by stacking the anode layer 40, the solid electrolyte layer 20, and the cathode layer 30 on the metal support 50, co-sintering them with the heat conduction suppression layer 60, forming a reforming catalyst by an impregnation method, and welding the heat conduction suppression layer 60 to the separator 10.

[0039] According to the fuel cell 100 and the manufacturing method for the fuel cell 100 of the first embodiment described above, the following effects can be obtained.

[0040] In the fuel cell 100, a heat conduction suppression layer 60 that suppresses heat conduction from the separator 10 to the metal support 50 is formed between the metal support 50 and the separator 10 at the site where the fuel cell 100 and the separator 10 are joined. This increases the distance from the separator 10 to the metal support 50, and suppresses heat from the separator 10, such as welding heat, from being transmitted to the metal support 50 and affecting the reforming catalyst inside the metal support 50. This prevents sintering of the reforming catalyst inside the metal support 50, and prevents a decrease in power generation efficiency.

[0041] In the fuel cell 100, the porosity of the thermal conduction suppression layer 60 is greater than the porosity of the metal support 50. Therefore, the thermal conduction area of ​​the thermal conduction suppression layer 60 is smaller than that of the metal support 50, and heat from the separator 10, such as welding heat, is less likely to be transmitted to the metal support 50. Therefore, the reforming catalyst in the metal support 50 is more likely to be prevented from being affected by heat, and sintering and the like can be more effectively prevented.

[0042] In the fuel cell 100, the thermal conduction suppression layer 60 is made of the same material as the metal support 50. This strengthens the bond at the interface between the thermal conduction suppression layer 60 and the metal support 50 (current collecting bond on the anode side), improving power generation performance.

[0043] In the fuel cell 100, the thermal conduction suppression layer 60 carries a substance having a lower thermal conductivity than the material constituting the metal support 50. This makes the thermal conduction suppression layer 60 lower in thermal conductivity than the metal support 50, making it more difficult for heat from the separator 10 to be transmitted to the metal support 50. This further suppresses the reforming catalyst in the metal support 50 from being affected by heat, making it possible to further prevent sintering and the like.

[0044] In the fuel cell 100, the separator 10 is made of an uneven member having a first contact portion 11 that contacts the lower surface of one of the adjacent fuel cells 100, a second contact portion 12 that contacts the upper surface of the other fuel cell 100, and a connecting portion 13 that connects the first contact portion 11 and the second contact portion 12, and the heat conduction suppression layer 60 is formed at a portion of the fuel cell 100 that contacts the first contact portion 11. In this way, since the heat conduction suppression layer 60 is formed between the separator 10 and the metal support 50 at the portion where the separator 10 and the fuel cell 100 contact each other, the distance from the separator 10 to the metal support 50 is increased. Therefore, the reforming catalyst inside the metal support 50 is less susceptible to the effect of heat from the separator 10, and sintering and the like can be prevented.

[0045] In the fuel cell 100, the weld beads 16 are formed only within the heat conduction suppression layer 60. In other words, the weld beads 16, which serve as a heat conduction path for transmitting heat from the separator 10, do not extend into the interior of the metal support 50. Therefore, the heat from the separator 10 is not easily transmitted to the reforming catalyst in the metal support 50, and sintering of the reforming catalyst is prevented.

[0046] In the fuel cell 100, the heat conduction suppression layer 60 is formed in the vicinity of the portion where the weld bead 16 is formed. Therefore, heat from the separator 10 is not easily conducted to the reforming catalyst in the metal support 50, and sintering of the reforming catalyst is prevented.

[0047] The manufacturing method of the fuel cell 100 includes the following steps. That is, the anode layer 40, the solid electrolyte layer 20, and the cathode layer 30 are laminated in this order on the metal support 50, and then the metal support 50 is co-sintered with the heat conduction suppression layer 60 from the lower surface side thereof to form a laminate. Then, a reforming catalyst is formed on the anode layer 40 and the metal support 50, and the lower surface of the heat conduction suppression layer 60 in the laminate is bonded to the separator 10. In this way, since the heat conduction suppression layer 60 is co-sintered with the metal support 50, the anode layer 40, the solid electrolyte layer 20, and the cathode layer 30, the bonding between the layers can be made stronger than when each layer is sintered separately, and the manufacturing process can be simplified.

[0048] The manufacturing method of the fuel cell 100 involves impregnating the anode layer 40 and the metal support 50 with a reforming catalyst solution to form the reforming catalyst. By forming the reforming catalyst using the impregnation method, the catalyst penetrates into the interior of the porous metal, and the specific surface area of ​​the catalyst becomes larger, compared to when the catalyst is formed by a spray coating method or the like. This increases the catalytic activity, improves the catalytic performance, and improves the power generation efficiency of the fuel cell 100.

[0049] In this embodiment, the thermal conduction suppressing layer 60 is formed only between the metal support 50 and the first contact portion 11 of the separator 10, but the thermal conduction suppressing layer 60 may also be formed in other portions of the lower surface of the metal support 50. For example, the thermal conduction suppressing layer 60 may be formed on the entire lower surface of the metal support 50.

[0050] In this embodiment, the separator 10 is fixed to the fuel cell 100 by welding the first contact portion 11 and the heat conduction suppressing layer 60, but the method of joining the separator 10 and the fuel cell 100 is not limited to welding. For example, a method such as electric current joining, which is performed by Joule heat when electricity is passed through, may be used.

[0051] As in the present embodiment, the thermal conduction suppression layer 60 is preferably made of a porous metal having a higher porosity than the metal support 50, but is not necessarily limited to this. For example, the thermal conduction suppression layer 60 and the metal support 50 may have substantially the same porosity.

[0052] Furthermore, as in this embodiment, it is preferable that the thermal conduction suppression layer 60 is made of the same material as the metal support 50, but this is not necessarily limited to this, and the thermal conduction suppression layer 60 may be formed of a material different from the metal support 50 (including materials other than porous materials) as long as the distance between the metal support 50 and the separator 10 can be increased.

[0053] Furthermore, as in this embodiment, it is preferable that the thermal conduction suppression layer 60 is supported by a substance having a lower thermal conductivity than the material constituting the metal support 50, but this is not necessarily limited to this, and the thermal conduction suppression layer 60 does not necessarily have to support such a substance.

[0054] In addition, in this embodiment, the separator 10 is made of an uneven member, but the shape of the separator 10 is not necessarily limited to this as long as the shape allows the air flow path 14 and the fuel flow path 15 to be formed.

[0055] In addition, as in this embodiment, the method of manufacturing the fuel cell 100 preferably involves stacking the anode layer 40, the solid electrolyte layer 20, and the cathode layer 30 in this order on the metal support 50, and then co-sintering them with the heat conduction suppression layer 60; however, this is not necessarily limited to this, and each layer may be sintered separately.

[0056] In addition, as in this embodiment, the manufacturing method for the fuel cell 100 is preferably to form the reforming catalyst using an impregnation method, but this is not necessarily limited to this, and any known method for forming the reforming catalyst may be used.

[0057] In addition, in this embodiment, the reforming catalyst is formed inside the anode layer 40 and the metal support 50, but the present invention is not limited to this, and the reforming catalyst may be formed on either the anode layer 40 or the metal support 50. Even when the reforming catalyst is formed on either the anode layer 40 or the metal support 50, the heat conduction suppression layer 60 prevents sintering of the reforming catalyst inside the anode layer 40 or the metal support 50.

[0058] Second embodiment A fuel cell 100 according to the second embodiment will be described with reference to Fig. 4. Note that the same elements as those in the first embodiment are given the same reference numerals, and the description thereof will be omitted.

[0059] 4 is a schematic configuration diagram of a fuel cell 100 according to a second embodiment. This embodiment differs from the first embodiment in that the fuel cell 100 has a reforming layer 70.

[0060] As in the first embodiment, a heat conduction suppression layer 60 is formed on the underside of the fuel cell 100 in a portion that abuts against the first contact portion 11 of the separator 10. Meanwhile, as shown in Fig. 4, a modified layer 70 is formed on the underside of the fuel cell 100 in a portion that does not abut against the first contact portion 11 of the separator 10 (i.e., a portion where the heat conduction suppression layer 60 is not formed).

[0061] The reforming layer 70 is made of a reforming catalyst in which a catalytic metal is supported on a catalyst support. The catalyst support of the reforming catalyst constituting the reforming layer 70 is made of cerium oxide (CeO2), aluminum oxide (Al2O3), zirconia (ZrO2), barium oxide (BaO), yttrium oxide (Y2O3), solid solution oxides of these, etc. The catalytic metal of the reforming catalyst constituting the reforming layer 70 includes nickel (Ni), platinum (Pt), rhodium (Rh), palladium (Pd), iridium (Ir), manganese (Mn), cobalt (Co), etc.

[0062] The modified layer 70 is formed on the underside of the metal support 50 by spray coating in a portion of the underside of the fuel cell 100 that does not come into contact with the first contact portion 11 of the separator 10.

[0063] By providing the reforming layer 70 made of the reforming catalyst in a portion of the underside of the fuel cell 100 that does not come into contact with the first contact portion 11 of the separator 10 in this manner, the catalytic activity of the fuel cell 100 is improved.

[0064] Furthermore, the catalyst carrier made of an oxide can suppress carbon deposition in the fuel cell 100.

[0065] In this embodiment, the reforming layer 70 is formed by a spray coating method, but this is not necessarily limited to this, and the reforming layer 70 made of the reforming catalyst may be formed by any known method.

[0066] Although the embodiments of the present invention have been described above, the above-mentioned embodiments merely show some of the application examples of the present invention, and it is not intended that the technical scope of the present invention be limited to the specific configurations of the above-mentioned embodiments.

[0067] Although the above-described embodiments have been described as separate embodiments, they may be combined as appropriate.

Claims

1. A fuel cell stack is formed by stacking fuel cells with separators interposed therebetween, The battery is constructed by stacking an anode layer, a solid electrolyte layer, and a cathode layer in that order on a metal support on a separator. the metal support and the anode layer are made of porous metal, and a reforming catalyst is formed inside at least one of the metal support and the anode layer; a heat conduction suppression layer is formed between the metal support and the separator at least at a portion where the fuel cell and the separator are joined, the heat conduction suppression layer being joined to the separator and suppressing heat conduction from the separator to the metal support; Fuel cell.

2. The fuel cell according to claim 1 , The thermal conduction suppression layer is made of a porous metal, The thermal conduction suppression layer has a larger porosity than the metal support. Fuel cell.

3. 3. The fuel cell according to claim 1 or 2, The heat conduction suppression layer is made of the same material as the metal support. Fuel cell.

4. 4. The fuel cell according to claim 1, The thermal conduction suppression layer carries a substance having a thermal conductivity lower than that of a material constituting the metal support. Fuel cell.

5. 5. A fuel cell according to claim 1, the separator is made of an uneven member having a first contact portion that contacts a lower surface of one of the adjacent fuel cell units, a second contact portion that contacts an upper surface of the other of the adjacent fuel cell units, and a connecting portion that connects the first contact portion and the second contact portion, the heat conduction suppression layer is formed in a portion of the fuel cell that contacts the first contact portion, Fuel cell.

6. 5. A fuel cell according to claim 1, the separator is made of an uneven member having a first contact portion that contacts a lower surface of one of the adjacent fuel cell units, a second contact portion that contacts an upper surface of the other of the adjacent fuel cell units, and a connecting portion that connects the first contact portion and the second contact portion, the heat conduction suppression layer is formed in a portion of the fuel cell that contacts the first contact portion, a reforming layer made of a catalyst in which a catalytic metal is supported on a catalyst support made of an oxide is formed on a portion of the lower surface of the fuel cell that is not in contact with the first contact portion; Fuel cell.

7. 7. A fuel cell according to claim 1, the separator and the thermal conduction suppression layer are joined by welding, and a weld bead formed by the welding is formed only within the thermal conduction suppression layer. Fuel cell.

8. A fuel cell according to any one of claims 1 to 7, the separator and the heat conduction suppressing layer are joined by welding, The heat conduction suppression layer is formed in the vicinity of a portion where a weld bead is generated by the welding. Fuel cell.

9. an anode layer, a solid electrolyte layer, and a cathode layer, each made of a porous metal, are laminated in this order on a metal support made of a porous metal, and then the anode layer, the solid electrolyte layer, and the cathode layer are co-sintered with a heat conduction suppression layer made of a porous metal from the lower surface side of the metal support to be integrated together to form a laminate; forming a reforming catalyst on at least one of the anode layer and the metal support; a lower surface of the thermal conduction suppressing layer of the laminate is joined to a separator; A method for manufacturing a fuel cell.

10. A method for producing a fuel cell according to claim 9, comprising the steps of: The reforming catalyst is formed on at least one of the anode layer and the metal support by impregnating the anode layer and the metal support with a reforming catalyst solution. A method for manufacturing a fuel cell.

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