Fuel cell and method for manufacturing the same

Abstract

To provide a fuel cell and a method of manufacturing the same that, when impregnating one electrode layer with a catalyst solution, can prevent the catalyst solution from permeating the other electrode layer with certainty.SOLUTION: A method of manufacturing a fuel cell includes the following steps of: preparing a laminate; forming a step at an end part of the laminate; forming an end dense ceramic layer so as to cover the step; and supporting a cathode catalyst and an anode catalyst on top of a porous metal layer and a porous ceramic layer.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] A known fuel cell has a ceramic electrolyte layer and an anode and a cathode arranged to sandwich the electrolyte layer. A known fuel cell has each electrode with a porous structure and a catalyst supported on each electrode.

[0003] One example of a method for manufacturing a fuel cell in which a catalyst is supported on an electrode is described in Patent Document 1 (U.S. Patent Application Publication No. 2018 / 0323443). Patent Document 1 describes a method in which a porous ceramic electrode layer is fabricated, a first surface of the fabricated electrode layer is impregnated with a cathode catalyst precursor (solution), and a second surface of the fabricated electrode layer is impregnated with an anode catalyst precursor (solution) (e.g., claim 13). Patent Document 1 also describes the application of an acrylic paint mask to areas not intended for impregnation when impregnating the electrode layer with the precursors of each catalyst (particularly, paragraphs 0032 to 0033 of Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] U.S. Patent Application Publication No. 2018 / 0323443 Summary of the Invention [Problem to be solved by the invention]

[0005] As described above, the anode and cathode electrodes are arranged to sandwich the electrolyte layer. When the electrodes are impregnated with the anode catalyst solution, the solution must not seep into the area that will become the cathode. Conversely, when the electrodes are impregnated with the cathode catalyst solution, it is necessary to prevent the solution from seeping into the area that will become the anode. According to the method described in Patent Document 1, an acrylic paint mask is used to protect the electrode layer on the side that is not intended to be impregnated. However, even if an acrylic paint mask is used, there is a possibility that the solution impregnated into one electrode layer will wrap around the edge of the electrolyte layer and reach the other electrode layer. As a result, there is a possibility that the anode and cathode electrodes will be short-circuited.

[0006] Therefore, an object of the present invention is to provide a fuel cell and a manufacturing method thereof that can prevent the catalyst solution from seeping into one electrode layer when the catalyst solution is impregnated into the other electrode layer. [Means for solving the problem]

[0007] A method for manufacturing a fuel cell according to the present invention includes the steps of: preparing a laminate having an electrolyte layer, which is a dense ceramic layer; first and second porous ceramic layers sandwiching the electrolyte layer; and first and second porous metal layers respectively disposed on the first and second porous ceramic layers; removing at least one of the first and second porous metal layers at the edge of the laminate to form a step; coating the edge of the laminate with a dense edge ceramic-forming material so as to cover the step; firing the coated dense edge ceramic-forming material to form a dense edge ceramic layer; and, after the dense edge ceramic layer is formed, impregnating the first porous metal layer and the first porous ceramic layer with a cathode catalyst solution to support the cathode catalyst, and impregnating the second porous metal layer and the second porous ceramic layer with an anode catalyst solution to support the anode catalyst.

[0008] Furthermore, a fuel cell according to the present invention includes a stack having an electrolyte layer that is a dense ceramic layer, and an anode electrode layer and a cathode electrode layer that are disposed so as to sandwich the electrolyte layer, and an end dense ceramic layer that is a dense ceramic layer and is disposed so as to cover an end of the stack. The anode electrode layer and the cathode electrode layer support an anode catalyst and a cathode catalyst, respectively. The anode electrode layer includes an anode porous ceramic layer disposed on the electrolyte layer, and an anode porous metal layer disposed on the anode porous ceramic layer. The cathode electrode layer includes a cathode porous ceramic layer disposed on the electrolyte layer, and a cathode porous metal layer disposed on the cathode porous ceramic layer. At least one end of the anode porous metal layer and the cathode porous metal layer is located inside the end of the electrolyte layer and is covered by the end dense ceramic layer. [Effects of the Invention]

[0009] According to the present invention, a fuel cell and a manufacturing method thereof are provided that can prevent the catalyst solution from seeping into one electrode layer when the other electrode layer is impregnated with the catalyst solution. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic cross-sectional view showing the main parts of a fuel cell according to a first embodiment. [Figure 2] FIG. 2 is a flow chart that schematically shows a method for manufacturing a fuel cell. [Figure 3] FIG. 3 is a schematic cross-sectional view showing the laminate produced in step S1. [Figure 4] FIG. 4 is a schematic cross-sectional view showing the shape of the laminate after the step is formed. [Figure 5] FIG. 5 is a schematic cross-sectional view showing a fuel cell according to the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] [First embodiment] The first embodiment will be described below with reference to the drawings.

[0012] (1)Fuel cell First, the configuration of a fuel cell 1 manufactured in this embodiment will be described. Fig. 1 is a schematic cross-sectional view showing a main part (electrolyte electrode assembly) of a fuel cell 1 according to the first embodiment. The fuel cell 1 according to this embodiment is a solid oxide fuel cell. The fuel cell 1 has a laminate 10 and an end dense ceramic layer 5.

[0013] The laminate 10 has an electrolyte layer 2, a cathode electrode 3, and an anode electrode 4. The electrolyte layer 2 is a dense ceramic layer. On the other hand, the cathode electrode 3 and the anode electrode 4 are both porous. The cathode electrode 3 and the anode electrode 4 are disposed so as to sandwich the electrolyte layer 2. The cathode electrode 3 and the anode electrode 4 support a cathode catalyst and an anode catalyst, respectively. The cathode electrode 3 has a cathode porous ceramic layer 3-1 disposed on the electrolyte layer 2 and a cathode porous metal layer 3-2 disposed on the cathode porous ceramic layer 3-1. Similarly, the anode electrode 4 has an anode porous ceramic layer 4-1 disposed on the electrolyte layer 2 and an anode porous metal layer 4-2 disposed on the anode porous ceramic layer 4-1. The ends of each porous metal layer (3-2 and 4-2) are located inside the ends of the electrolyte layer 2. This forms steps at the ends of the laminate 10. The ends of the porous ceramic layers (3-1 and 4-1) are aligned with the ends of the electrolyte layer 2. When viewed from above, the distance from the end of the electrolyte layer 2 to the end of each porous metal layer (3-2 and 4-2) is, for example, 0.2 to 5 mm, and preferably 0.5 to 2 mm.

[0014] The end dense ceramic layer 5 is composed of a dense ceramic layer and covers the end of the laminate 10. Specifically, the end dense ceramic layer 5 covers the above-mentioned steps. The end face of the electrolyte layer 2 is also covered by the end dense ceramic layer 5. The end dense ceramic layer 5 is provided around the entire periphery of the end of the laminate 10. Moreover, the end dense ceramic layer 5 is provided only on the outer peripheral edge of the laminate 10. In other words, the upper surfaces of the cathode electrode 3 and the anode electrode 4 are exposed to the outside. In this specification, the upper surface of each electrode (3 and 4) refers to the upper surface when the surface on the electrolyte layer 2 side is considered to be the lower surface.

[0015] In the fuel cell 1 according to this embodiment, a cathode gas is supplied to the cathode electrode 3, and an anode gas is supplied to the anode electrode 4. A cell reaction using the cathode gas and the anode gas proceeds at the cathode electrode 3 and the anode electrode 4, allowing the cell to function as a cell. To improve cell performance, the gas must be separated between the cathode electrode 3 and the anode electrode 4. In this regard, in this embodiment, a step is provided at the end of the stack 10, which lengthens the path from the end of the cathode porous metal layer 3-2 around the end of the electrolyte layer 2 to the anode porous metal layer 4-2. This prevents gas from traveling from one electrode around the end to the other electrode. This results in improved gas sealing.

[0016] Next, each part will be described in detail.

[0017] (electrolyte layer) As described above, the electrolyte layer 2 is formed of a dense ceramic layer. Ceramics refers to sintered bodies of inorganic materials, and is a concept that encompasses not only nonmetallic oxides but also metal oxides. The electrolyte layer 2 is only required to be capable of conducting oxide ions while being impermeable to gases. For example, the electrolyte layer 2 can be formed of solid oxide ceramics. Examples of solid oxide ceramics include, but are not limited to, zirconia-containing materials. Examples of zirconia-containing materials include stabilized zirconia doped with yttria, neodymium oxide, samarium, gadolinium, scandium, and the like. More preferably, the electrolyte layer 2 contains 5 to 97% zirconia by volume. The thickness of the electrolyte layer 2 is, for example, 0.5 to 20 μm, preferably 1 to 10 μm.

[0018] (Cathode and anode electrodes) The cathode electrode 3 is a part that converts oxygen molecules contained in the cathode gas into oxide ions, while the anode electrode 4 is a part that causes an anode gas such as hydrogen to react with the oxide ions to generate electrons.

[0019] As described above, a cathode catalyst is supported on the cathode electrode 3. For example, praseodymium oxide or the like is used as the cathode catalyst. The cathode catalyst is supported on both the cathode porous ceramic layer 3-1 and the cathode porous metal layer 3-2.

[0020] An anode catalyst is supported on the anode electrode 4. Examples of the anode catalyst include nickel (Ni), palladium (Pd), platinum (Pt), ruthenium (Ru), a Ni-Fe alloy, a Ni-Co alloy, a Fe-Co alloy, a Ni-Cu alloy, and a Pd-Pt alloy. The anode catalyst is supported on both the anode porous ceramic layer 4-1 and the anode porous metal layer 4-2.

[0021] In addition to functioning as an electrode, each of the porous ceramic layers (3-1 and 4-1) has the function of joining each of the porous metal layers (3-2 and 4-2) to the electrolyte layer 2. Each of the porous ceramic layers (3-1 and 4-1) also has the function of conducting oxide ions.

[0022] The material for the porous ceramic layers (3-1 and 4-1) is not particularly limited, but may be, for example, a solid oxide ceramic, such as stabilized zirconia doped with yttria, neodymium oxide, samarium, gadolinium, scandium, or the like.

[0023] In a preferred embodiment, the electrolyte layer 2 contains zirconia, and at least one of the porous ceramic layers (3-1 and 4-1) also contains zirconia. More preferably, the electrolyte layer 2 and all of the porous ceramic layers (3-1 and 4-1) contain zirconia. The layers containing zirconia are firmly bonded to each other due to the interdiffusion of zirconia. When both the electrolyte layer 2 and the porous ceramic layers (3-1 and 4-1) contain zirconia, they can be firmly bonded to each other. Furthermore, when each of the porous ceramic layers (3-1 and 4-1) contains zirconia, the oxide ion conduction function of each of the porous ceramic layers (3-1 and 4-1) is improved. The zirconia content in each of the porous ceramic layers (3-1 and 4-1) is preferably 50% or more by volume fraction.

[0024] The thickness of each of the porous ceramic layers (3-1 and 4-1) is, for example, 0.3 to 50 μm, preferably 0.5 to 30 μm.

[0025] The porous metal layers (3-2 and 4-2) are provided for purposes such as maintaining the shape. That is, the porous metal layers (3-2 and 4-2) are provided as metal supports. By providing the porous metal layers (3-2 and 4-2), the overall shape can be maintained even when the electrolyte layer 2 and the porous ceramic layers (3-1 and 4-1) are thin.

[0026] The thickness of each porous metal layer (3-2 and 4-2) is determined from the viewpoint of shape retention, and is, for example, 50 to 1000 μm, preferably 100 to 500 μm.

[0027] The material of each porous metal layer (3-2 and 4-2) is not particularly limited as long as it is a metallic material having electrical conductivity. Preferably, each porous metal layer (3-2 and 4-2) contains Fe and Cr. The inclusion of Fe and Cr improves oxidation resistance and enables the layer to withstand high-temperature operation. Preferably, the material of each porous metal layer (3-2 and 4-2) is SUS.

[0028] (Dense ceramic layer at the edge) The end dense ceramic layer 5 is provided to protect the end of the laminate 10. By providing the end dense ceramic layer 5, it is possible to suppress vapor phase diffusion of the metal constituting the porous metal layers (3-2 and 4-2) from the end.

[0029] The constituent material of the end dense ceramic layer 5 is not particularly limited, and may be, for example, the same material as that of the electrolyte layer 2. Preferably, the end dense ceramic layer 5 contains zirconia. The content of zirconia in the end dense ceramic layer 5 is, for example, 5 to 50% by volume fraction.

[0030] In a preferred embodiment, at least one of the porous ceramic layers (3-1 and 4-1) and the electrolyte layer 2 contains zirconia, and the end dense ceramic layer 5 also contains zirconia. By adopting such a configuration, the end dense ceramic layer 5 can be more firmly bonded to the laminate 10 due to interdiffusion of zirconia. In a more preferred embodiment, all of the porous ceramic layers (3-1 and 4-1), the electrolyte layer 2, and the end dense ceramic layer 5 contain zirconia.

[0031] In a preferred embodiment, the surface roughness R2 of the end surface of each porous metal layer (3-2 and 4-2) is greater than the surface roughness R1 of the upper surface thereof. By adopting such a configuration, the bonding between each porous metal layer (3-2 and 4-2) and the end dense ceramic layer 5 becomes stronger due to the anchor effect.

[0032] (2) Fuel cell manufacturing method Next, a method for manufacturing the fuel cell 1 according to this embodiment will be described. FIG. 2 is a flowchart that outlines the method for manufacturing the fuel cell. The manufacturing method according to this embodiment includes a step of producing a laminate (step S1), a step of forming a step (step S2), a step of coating the end portion with a material for forming a dense ceramic (step S3), a step of firing the material for forming the end portion with a dense ceramic (step S4), and a step of impregnating with a catalyst solution (step S5). Each step will be described in detail below.

[0033] Step S1: Fabrication of laminate First, a laminate is fabricated. FIG. 3 is a schematic cross-sectional view showing the laminate 10 fabricated in this step. This laminate has an electrolyte layer 2, first and second porous ceramic layers (3-1-a and 4-1-a), and first and second porous metal layers (3-2-a and 4-2-a). The first and second porous ceramic layers (3-1-a and 4-1-a) are the portions that will eventually become the anode and cathode porous ceramic layers (3-1 and 4-1), respectively. The first and second porous metal layers (3-2-a and 4-2-a) are the portions that will eventually become the anode and cathode porous metal layers (3-2 and 4-2), respectively.

[0034] In detail, first, a green laminate is formed (step S1-1). The green laminate is a laminate at a stage before the ceramic layers are formed by firing. The green laminate can be formed, for example, by tape casting. Specifically, first, slurries serving as raw materials for each layer included in the laminate are prepared. Then, each prepared slurry is molded into a sheet, and the obtained sheets are laminated. This results in a green laminate. Note that if the sheet is in the shape of a long piece, the green laminate is cut to the desired size as needed. It is preferable that all five layers of the green laminate are approximately the same size. This makes it less likely that warping will occur during cell firing (step S1-2), which will be described later.

[0035] Next, the green laminate is fired (step S1-2). This forms a ceramic layer, and a laminate having the configuration shown in FIG. 3 is obtained. The firing process in this step is preferably carried out in a reducing atmosphere. For example, the firing process is carried out in an inert gas atmosphere containing hydrogen. The firing temperature may be any temperature at which a ceramic layer is formed. The firing temperature is, for example, 1000 to 1500°C, preferably 1200 to 1400°C.

[0036] Step S2: Step formation Next, a step is formed at the end of the stack. Fig. 4 is a schematic cross-sectional view showing the shape of the stack after the step is formed. As shown in Fig. 4, the first porous metal layer 3-2-a and the second porous metal layer 4-2-a are removed from the end of the stack.

[0037] The method for removing the porous metal layers (3-2-a and 4-2-a) is not particularly limited, and a chemical method or a mechanical method may be used.

[0038] Preferably, the porous metal layers (3-2-a and 4-2-a) are removed by etching using a liquid. By performing etching using a liquid, the end surfaces of the porous metal layers (3-2-a and 4-2-a) become rough. As a result, as described above, the dense ceramic end layer 5 can be more firmly bonded to the porous metal layers (3-2-a and 4-2-a) due to the anchor effect. The liquid used for etching may be any liquid that dissolves the porous metal layers (3-2-a and 4-2-a), but typically an acid is used. In this step, a mask material may be provided, if necessary, in areas that are not intended to be removed.

[0039] Step S3: Coating the edge with material for forming dense ceramics Next, a material for forming a dense edge ceramic is coated onto the edge of the laminate 10. The material for forming a dense edge ceramic is coated onto the region where the dense edge ceramic layer 5 is to be formed. That is, the material for forming a dense edge ceramic is coated so as to cover the step formed in step S2.

[0040] Preferably, a slurry is prepared as the material for forming the dense edge ceramic layer, and the edge of the laminate 10 is dipped into this slurry, thereby making it possible to coat the material for forming the dense edge ceramic uniformly.

[0041] Step S4: Firing (forming a dense ceramic layer at the edge) Next, the coated end dense ceramic-forming material is fired, whereby the coated end dense ceramic-forming material is densified and an end dense ceramic layer 5 is formed.

[0042] The firing temperature in this step may be any temperature at which the coated material for forming dense edge ceramics is sintered and densified. The firing in this step is preferably carried out in a reducing atmosphere, similar to step S1-2.

[0043] Preferably, the firing temperature in this step is lower than the firing temperature in step S1-2. By firing at a temperature lower than the firing temperature in step S1-2, repeated application of high-temperature heat input to the laminate 10 is prevented. As a result, bending of the laminate 10 and densification of the porous layer can be prevented. The firing temperature in this step is, for example, 900 to 1400°C, preferably 1100 to 1300°C.

[0044] Step S5: Impregnation with catalyst solution Next, the first porous metal layer 3-2-a and the first porous ceramic layer 3-1-a are impregnated with a cathode catalyst solution to support the cathode catalyst, and the second porous metal layer 4-2-a and the second porous ceramic layer 4-1-a are impregnated with an anode catalyst solution to support the anode catalyst, thereby obtaining the structure (electrolyte electrode assembly) shown in FIG.

[0045] Specifically, a cathode catalyst solution is first supplied to the upper surface of the first porous metal layer 3-2-a and allowed to soak into the first porous metal layer 3-2-a and the first porous ceramic layer 3-1-a. An anode catalyst solution is then supplied to the upper surface of the second porous metal layer 4-2-a and allowed to soak into the second porous metal layer 4-2-a and the second porous ceramic layer 4-1-a. Heat treatment is then performed to deposit the cathode catalyst and the anode catalyst. This allows the cathode catalyst and the anode catalyst to be supported on each electrode. As a result, the first porous metal layer 3-2-a and the first porous ceramic layer 3-1-a function as the cathode electrode 3, and the second porous metal layer 4-2-a and the second porous ceramic layer 4-1-a function as the anode electrode 4.

[0046] During impregnation with each catalyst solution, the presence of the end dense ceramic layer 5 prevents the catalyst solution from flowing out from the outer peripheral edge of the porous metal layer (3-2-a and 4-2-a).

[0047] In addition, because a step is formed in step S2, the path from one porous metal layer (3-2-a or 4-2-a) around the edge to the other porous metal layer (4-2-a or 3-2-a) is longer than when there is no step. Therefore, the catalyst solution impregnated in one electrode is less likely to reach the opposite electrode. As a result, short circuits are more reliably prevented.

[0048] It is noted that the order in which the cathode catalyst solution and the anode catalyst solution are impregnated may not matter, and the impregnation and heat treatment with the cathode catalyst solution and the anode catalyst solution may each be carried out multiple times in order to support a desired amount of catalyst.

[0049] The method described above can obtain the structure (electrolyte electrode assembly) shown in Fig. 1. The obtained electrolyte electrode assembly can be combined with other members as needed and used as a fuel cell 1.

[0050] Next, the configuration and effects of this embodiment will be summarized below.

[0051] According to this embodiment, a laminate is fabricated (Step S1), which includes a dense ceramic electrolyte layer, first and second porous ceramic layers sandwiching the electrolyte layer, and first and second porous metal layers respectively disposed on the first and second porous ceramic layers. Next, at least one of the first and second porous metal layers is removed from the edge of the laminate, forming a step (Step S2). Next, a dense edge ceramic-forming material is coated on the edge of the laminate so as to cover the step (Step S3). Next, the coated dense edge ceramic-forming material is fired to form a dense edge ceramic layer (Step S4). Next, the first porous metal layer and the first porous ceramic layer are impregnated with a cathode catalyst solution to support the cathode catalyst. Furthermore, the second porous metal layer and the second porous ceramic layer are impregnated with an anode catalyst solution to support the anode catalyst (Step S5). By employing such a process, it is possible to prevent the impregnated catalyst solutions from permeating around the ends and seeping into the opposite side in step S5.

[0052] Furthermore, according to this embodiment, the number of manufacturing steps can be reduced compared to, for example, the method described in Patent Document 1. In the method described in Patent Document 1, when the cathode electrode side is impregnated with a catalyst solution, the anode side electrode must be protected with an acrylic paint mask, and conversely, when the anode electrode side is impregnated with a catalyst solution, the cathode side electrode must be protected. This method requires repeated formation and removal of the acrylic paint mask. In contrast, according to this embodiment, the end dense ceramic layer 5 functions as a mask during impregnation with each catalyst solution. There is no need to repeatedly form and remove the end dense ceramic layer 5. Therefore, the method according to this embodiment is advantageous in terms of shortening the manufacturing steps.

[0053] In a preferred embodiment, at least one of the porous ceramic layers (3-1 and 4-1) contains zirconia in a volume fraction of 50% or more. This improves the oxide ion conductivity of the porous ceramic layer. Furthermore, when the electrolyte layer 2 contains zirconia and the porous ceramic layer (3-1 or 4-1) also contains zirconia, the porous ceramic layer (3-1 or 4-1) can be firmly bonded to the electrolyte layer 2.

[0054] In a preferred embodiment, at least one of the porous ceramic layers (3-1 and 4-1) and the electrolyte layer 2 contains zirconia, and the end dense ceramic layer 5 contains zirconia. By adopting such a configuration, the end dense ceramic layer 5 can be firmly bonded to the laminate 10.

[0055] In a preferred embodiment, at least one of the porous metal layers (3-2 and 4-2) contains Fe and Cr, which improves oxidation resistance and enables the porous metal layer to withstand high temperature operation.

[0056] In a preferred embodiment, the surface roughness R2 of the end face of at least one of the porous metal layers (3-2 and 4-2) is greater than the surface roughness R1 of the upper face. With this configuration, the end dense ceramic layer 5 can be firmly bonded to the end of the porous metal layer (3-2 and 4-2) by the anchor effect.

[0057] In a preferred embodiment, in step S2, the steps are formed by etching using a liquid. By employing such a process, the surface roughness of the end faces of the porous metal layers (3-2-a and 4-2-a) becomes greater. As a result, the end dense ceramic layers 5 can be firmly bonded to the ends of the porous metal layers (3-2-a and 4-2-a) due to the anchor effect.

[0058] In a preferred embodiment, in step S3, the edge of the laminate 10 is coated with the material for forming the dense edge ceramic layer by dipping the edge of the laminate 10 in a slurry for forming the dense edge ceramic layer. By employing this step, the material for forming the dense edge ceramic layer can be uniformly coated.

[0059] In a preferred embodiment, the firing temperature in step S4 is lower than the firing temperature in step S1-2. By adopting such a configuration, it is possible to prevent bending of the laminate 10 and densification of the porous layer.

[0060] [Second embodiment] Next, a second embodiment will be described. Fig. 5 is a schematic cross-sectional view showing a fuel cell 1 according to a second embodiment. In the fuel cell 1 according to this embodiment, a metal frame 6 is added to the first embodiment.

[0061] The metal frame 6 is used to support the stack 10. That is, the stack 10 is placed on the metal frame 6. Specifically, the stack 10 is placed on the metal frame 6 so that the anode porous metal layer 4-2 faces the metal frame 6. The metal frame 6 is also arranged so that its opening overlaps the center of the upper surface of the anode porous metal layer 4-2. Therefore, the center of the upper surface of the anode porous metal layer 4-2 is exposed through the opening of the metal frame 6.

[0062] The metal frame 6 and the stack 10 are joined by welds 7. Specifically, the outer periphery of the upper surface of the anode porous metal layer 4-2 overlaps the frame portion of the metal frame 6. The outer periphery of the upper surface of the anode porous metal layer 4-2 and the metal frame 6 are joined by welds 7. The welds 7 may be provided in the form of spots or in a ring shape.

[0063] Furthermore, a sealing material 8 is provided on the metal frame 6, more peripherally than the welded portion 7. Specifically, the laminate 10 is arranged so that the end dense ceramic layer 5 is placed on the periphery of the metal frame 6. The sealing material 8 is provided so as to fill the gap between the end dense ceramic layer 5 and the metal frame 6. More specifically, the sealing material 8 is arranged so as to fill the gap between the outer periphery of the end dense ceramic layer 5 and the metal frame 6. For example, a glass material can be used as the sealing material 8.

[0064] The fuel cell 1 according to this embodiment can be obtained, for example, by the method described below. After the catalyst is supported in step S5 of the first embodiment, the stack 10 is placed on the metal frame 6 so that the anode porous metal layer 4-2 faces the metal frame 6. The metal frame 6 and the anode porous metal layer 4-2 are then joined by welding. Furthermore, a sealant 8 is placed on the outer periphery of the welded portion to seal between the end dense ceramic layer 5 and the metal frame 6. The sealant 8 can be formed, for example, by applying and drying a slurry for forming the sealant.

[0065] The fuel cell 1 according to this embodiment can be obtained by the method described above.

[0066] According to this embodiment, the metal frame 6 is joined to the stack 10 by welding, which increases the strength of the fuel cell 1. In addition, the provision of the sealant 8 prevents gas and other substances from leaking from the side of the anode electrode 4.

[0067] In this embodiment, the laminate 10 is placed on the metal frame 6 so that the anode electrode 4 faces the metal frame 6, but the laminate 10 may be placed so that the cathode electrode 3 faces the metal frame 6.

[0068] Furthermore, the metal frame 6 may be provided on both sides of the anode electrode 4 and the cathode electrode 3, rather than on only one side of the anode electrode 4 or the cathode electrode 3. In other words, the fuel cell 1 may have a configuration in which the stack 10 is sandwiched between a pair of metal frames 6.

[0069] Furthermore, the fuel cell 1 may have a stack type configuration in which a plurality of units are stacked, with the configuration shown in FIG. 5 being one unit. [Explanation of symbols]

[0070] 1 fuel cell, 2 electrolyte layer, 3 cathode electrode layer, 3-1 cathode porous ceramic layer, 3-2 cathode porous metal layer, 3-1-a first porous ceramic layer, 3-2-a first porous metal layer, 4 anode electrode layer, 4-1 anode porous ceramic layer, 4-2 anode porous metal layer, 4-1-a second porous ceramic layer, 4-2-a second porous metal layer, 5 end dense ceramic layer, 6 metal frame, 7 welded portion, 8 sealing material, 10 laminate

Claims

1. a step of producing a laminate including an electrolyte layer which is a dense ceramic layer, first and second porous ceramic layers provided so as to sandwich the electrolyte layer, and first and second porous metal layers provided on the first and second porous ceramic layers, respectively; removing at least one of the first and second porous metal layers at an end of the stack to form a step; a step of coating the end portion of the laminate with a material for forming an end dense ceramic so as to cover the step; sintering the coated end dense ceramic-forming material to form an end dense ceramic layer; After the end dense ceramic layer is formed, a step of impregnating the first porous metal layer and the first porous ceramic layer with a cathode catalyst solution to support a cathode catalyst, and impregnating the second porous metal layer and the second porous ceramic layer with an anode catalyst solution to support an anode catalyst; Equipped with A method for manufacturing a fuel cell.

2. The method of claim 1, the step of forming the step is performed by etching using a liquid; Manufacturing method.

3. The manufacturing method according to claim 1 or 2, The coating step includes a step of dipping the end portion of the laminate in a slurry for forming the end dense ceramic layer. Manufacturing method.

4. The manufacturing method according to claim 1 or 2, The step of preparing the laminate includes: preparing a green laminate; a green laminate firing step of firing the green laminate to form the laminate, a firing temperature in the step of forming the end dense ceramic layer is lower than a firing temperature in the step of firing the green laminate; Manufacturing method.

5. The manufacturing method according to claim 1 or 2, Furthermore, a step of placing the laminate on a metal frame such that the first or second porous metal layer faces the metal frame after the supporting step, and joining the metal frame and the first or second porous metal layer by welding; a step of disposing a sealing material so as to seal between the end dense ceramic layer and the metal frame at a portion outer than the welded portion; A manufacturing method comprising:

6. a laminate including an electrolyte layer that is a dense ceramic layer, and an anode electrode and a cathode electrode that are provided so as to sandwich the electrolyte layer; an end dense ceramic layer, which is a dense ceramic layer and is provided so as to cover an end of the laminate; and an anode catalyst and a cathode catalyst are supported on the anode electrode and the cathode electrode, respectively; The anode electrode is an anode porous ceramic layer provided on the electrolyte layer; an anode porous metal layer provided on the anode porous ceramic layer, The cathode electrode is a cathode porous ceramic layer provided on the electrolyte layer; a cathode porous metal layer provided on the cathode porous ceramic layer, at least one end of the anode porous metal layer and the cathode porous metal layer is located inside the end of the electrolyte layer and is covered with the end dense ceramic layer; fuel cell.

7. 7. The fuel cell according to claim 6, At least one of the anode porous ceramic layer and the cathode porous ceramic layer contains zirconia at a volume fraction of 50% or more. fuel cell.

8. 8. The fuel cell according to claim 6 or 7, At least one of the anode porous metal layer and the cathode porous metal layer contains Fe and Cr. fuel cell.

9. 8. The fuel cell according to claim 6 or 7, at least one layer among the anode porous ceramic layer, the cathode porous ceramic layer, and the electrolyte layer contains zirconia; The end dense ceramic layer contains zirconia. fuel cell.

10. 8. The fuel cell according to claim 6 or 7, At least one of the anode porous metal layer and the cathode porous metal layer has a surface roughness of an end surface greater than a surface roughness of an upper surface. fuel cell.

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