Solid oxide fuel cell and manufacturing method thereof

Abstract

A solid oxide fuel cell according to the present invention is provided with: a first electrode structure; an electrolyte layer that is superposed on the first electrode structure; and a second electrode structure that is superposed on the electrolyte layer. The first electrode structure comprises a first porous metal support layer and a first electrode layer. With respect to this solid oxide fuel cell, the first electrode structure is provided with: a filled part; and a first dam which is positioned outside the filled part when viewed along the stacking direction, while being densified so as to prevent the leakage of a filler to the outside of the filled part.

Description

[Technical Field]

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

[0002] A solid oxide fuel cell is a fuel cell that uses a solid material as an electrolyte. A solid oxide fuel cell typically has an electrolyte layer, an anode electrode, and a cathode electrode. The anode electrode and the cathode electrode are arranged so as to sandwich the electrolyte layer. During power generation, an anode gas is supplied to the anode electrode, and a cathode gas is supplied to the cathode electrode. A metal support layer may be provided on the outside of the anode electrode and / or the cathode electrode as a support material. The metal support layer must be gas permeable so that gas from the outside can be supplied to the electrode. Therefore, the metal support layer is typically formed from a porous material.

[0003] Because the metal support layer is porous, the supplied gas may leak from the edges of the metal support layer, which may result in the gas mixing between the two electrodes. To achieve efficient power generation, it is necessary to prevent gas leakage at the edges so that the gas is separated between the two electrodes.

[0004] In relation to the above, Patent Document 1 (JP2008-159428A) describes that a gas sealing region is formed by filling at least one region of a porous body with metallic glass, and that a solid oxide fuel cell is manufactured using this porous body. Summary of the Invention

[0005] According to the technology described in Patent Document 1, gas leakage is prevented in a gas sealing region filled with metallic glass. However, solid oxide fuel cells can reach high temperatures during operation. As a result, the metallic glass filled therein may soften. Furthermore, during operation, the internal pressure of one of the electrodes may increase due to the supply of gas. As a result, the softened metallic glass may flow outward due to the increased internal pressure, potentially impairing the gas sealing properties.

[0006] Therefore, an object of the present invention is to provide a solid oxide fuel cell in which gas sealing properties are not impaired even at high temperatures and high internal pressures, and a method for manufacturing the same.

[0007] The solid oxide fuel cell according to the present invention comprises a porous first electrode structure, an electrolyte layer laminated on the first electrode structure, and a second electrode structure laminated on the electrolyte layer. The first electrode structure has a first porous metal support layer and a first electrode layer provided between the first porous metal support layer and the electrolyte layer. The first electrode structure is provided with a filling section and a first dam. The filling section is a region in which pores are filled with a filling material. The filling section is provided so as to have a ring shape when viewed along the stacking direction. The first dam is located outside the filling section when viewed along the stacking direction. The first dam is a densified portion to prevent the filling material from leaking outside the filling section. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a top view of a solid oxide fuel cell according to a first embodiment. [Figure 2] FIG. 2 is a cross-sectional view showing the solid oxide fuel cell according to the first embodiment. [Figure 3] FIG. 3 is a schematic cross-sectional view showing a solid oxide fuel cell during the manufacturing process. [Figure 4] FIG. 4 is a schematic cross-sectional view showing a solid oxide fuel cell during the manufacturing process. [Figure 5] FIG. 5 is a schematic cross-sectional view showing a solid oxide fuel cell during the manufacturing process. [Figure 6] FIG. 6 is a schematic cross-sectional view showing a solid oxide fuel cell during the manufacturing process. [Figure 7] FIG. 7 is a schematic cross-sectional view showing a solid oxide fuel cell during the manufacturing process. [Figure 8] FIG. 8 is a schematic cross-sectional view showing an end portion of a solid oxide fuel cell according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0010] [First embodiment] Fig. 1 is a diagram of a solid oxide fuel cell 1 according to a first embodiment, viewed along the stacking direction, i.e., a top view of the solid oxide fuel cell. Fig. 2 is a cross-sectional view of the solid oxide fuel cell 1, showing the AA cross section in Fig. 1.

[0011] 1 and 2, a solid oxide fuel cell 1 generally includes a metal frame 7, a stack 5, and a sealing material 6. The stack 5 is supported by the metal frame 7. The sealing material 6 is provided to cover the end of the stack 5.

[0012] The laminate 5 has an electrolyte layer 2, a first electrode structure 3, and a second electrode structure 4. These are laminated. That is, the electrolyte layer 2 is laminated on the first electrode structure 3, and the second electrode structure 4 is laminated on the electrolyte layer 2. In other words, the electrolyte layer 2 is sandwiched between the first electrode structure 3 and the second electrode structure 4. One of the first electrode structure 3 and the second electrode structure 4 functions as an anode, and the other functions as a cathode. Note that the first electrode structure 3 may be the anode, or the second electrode structure 4 may be the anode. During operation, an anode gas is supplied to one of the first electrode structure 3 and the second electrode structure 4, and a cathode gas is supplied to the other.

[0013] The laminate 5 is supported by a metal frame 7 on the side of the first electrode structure 3. Specifically, the outer periphery of the first electrode structure 3 is positioned on the rim of the metal frame 7. The laminate 5 is joined to the metal frame 7 at this outer periphery by welding. In FIG. 2, the welded portion is shown as weld 10.

[0014] Furthermore, the center of the underside of the first electrode structure 3 is located above the opening in the metal frame 7. That is, the underside of the first electrode structure 3 is exposed at the center. With this configuration, it is possible to supply gas (anode gas or cathode gas) to the first electrode structure 3 through the opening in the metal frame 7.

[0015] The electrolyte layer 2 is formed of a dense ceramic layer. Ceramics refers to a sintered body of an inorganic material, and is a concept that encompasses not only non-metallic 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 a solid oxide ceramic. The solid oxide ceramic is not particularly limited, but examples thereof include zirconia-containing materials. Examples of zirconia-containing materials include stabilized zirconia doped with yttria, neodymium oxide, samarium, gadolinium, scandium, etc. The thickness of the electrolyte layer 2 is, for example, 0.5 to 20 μm, preferably 1 to 10 μm.

[0016] The first electrode structure 3 and the second electrode structure 4 each have a porous structure. Each of the first electrode structure 3 and the second electrode structure 4 has a two-layer structure. Specifically, the first electrode structure 3 has a first electrode layer 3-1 and a first porous metal support layer 3-2. The second electrode structure 4 has a second electrode layer 4-1 and a second porous metal support layer 4-2. The first electrode layer 3-1 and the second electrode layer 4-1 are disposed to sandwich the electrolyte layer 2 and are joined to the electrolyte layer 2. The first porous metal support layer 3-2 and the second porous metal support layer 4-2 are disposed on the outside of the first electrode layer 3-1 and the second electrode layer 4-1, respectively.

[0017] The first electrode layer 3-1 and the second electrode layer 4-1 are layers through which electrons are exchanged during power generation. The first electrode layer 3-1 and the second electrode layer 4-1 are made of porous ceramic layers. These porous ceramic layers can be made of, for example, solid oxide ceramics. Examples of solid oxide ceramics include stabilized zirconia doped with yttria, neodymium oxide, samarium, gadolinium, scandium, etc. The thickness of each of the first electrode layer 3-1 and the second electrode layer 4-1 is, for example, 0.3 to 50 μm, preferably 0.5 to 30 μm.

[0018] The first porous metal support layer 3-2 and the second porous metal support layer 4-2 are provided for purposes such as shape retention. By providing these support layers, the shape is maintained even when the electrolyte layer 2, the first electrode layer 3-1, and the second electrode layer 4-1 are thin. The thickness of each porous metal support 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. Each porous metal support layer (3-2 and 4-2) can be formed from, for example, Fe, Cr, etc.

[0019] In this embodiment, the first electrode structure 3 is provided with a filling portion 11, a first dam 8, and a second dam 9.

[0020] The filling portion 11 is a region where pores are filled with a filling material. The filling portion 11 has a ring-like shape when viewed along the stacking direction. The filling portion 11 is provided on the outer periphery of the first electrode structure 3. Specifically, the filling portion 11 is provided in the region where the first electrode structure 3 and the metal frame 7 overlap. Therefore, the width of the filling portion 11 when viewed along the stacking direction is smaller than the width of the portion where the first electrode structure 3 and the metal frame 7 overlap.

[0021] The filling section 11 is provided to prevent gas from leaking from the outer peripheral edge of the first electrode structure 3. As described above, the first electrode structure 3 is porous. Therefore, if the filling section 11 is not provided, gas supplied to the first electrode structure 3 may leak from the outer peripheral edge to the outside. In particular, the first porous metal support layer 3-2 is designed to be gas permeable, so gas is likely to leak from its edge. Although a sealing material 6 is provided at the edge of the laminate 5, it is difficult to completely prevent gas leakage using the sealing material 6 alone. In contrast, in this embodiment, the filling section 11 is provided, so gas supplied to the first electrode structure 3 is less likely to leak from the edge to the outside.

[0022] The filler is not particularly limited, but may include, for example, at least one selected from the group consisting of metal powder, glass, and ceramics (ceria, zirconia, etc.).

[0023] The filling portion 11 is preferably provided at a depth that reaches from the surface (lower surface) of the first electrode structure 3 to the electrolyte layer 2. Providing the filling portion 11 at such a depth more reliably prevents gas from leaking sideways from between the metal frame 7 and the electrolyte layer 2. Even if the filling portion 11 cannot completely prevent gas leakage, the leak path is narrowed, thereby reducing the internal pressure applied to the sealing material 6. This prevents damage to the sealing material 6 due to an increase in internal pressure, and improves the reliability of the sealing function at the end of the stack 5.

[0024] When viewed in the stacking direction, the first dam 8 is located outside the filling portion 11. The first dam 8 is a densified portion that prevents the filling material from leaking out of the filling portion 11. When viewed in the stacking direction, the first dam 8 is provided in a ring shape along the outer periphery of the first electrode structure 3.

[0025] As described above, the solid oxide fuel cell 1 may reach a high temperature during operation. As a result, the filler material filled in the filling section 11 may soften. In addition, since gas is supplied to the first electrode structure 3, the internal pressure may increase. If the first dam 8 were not provided, the fluidized filler material would flow outward as the internal pressure increased, and the function of the filling section 11 may be impaired. However, according to this embodiment, the first dam 8 is provided, and the filler material is blocked. Therefore, the function of the filling section 11, i.e., gas sealing ability, is maintained even at high temperatures and high internal pressures.

[0026] The first dam 8 only needs to be dense enough to prevent fluidization even when the temperature reaches a level high enough to fluidize the filler. The first dam 8 can be formed, for example, by heating and melting the metal that constitutes the first porous metal support layer 3-2 and filling the pores with the molten metal. For example, the first dam 8 can be formed by wire electric discharge machining, laser welding beads, or the like.

[0027] The second dam 9 is provided inside the filling section 11 when viewed along the stacking direction. The second dam 9 is a densified portion that prevents the filling material from leaking inside the filling section 11. The second dam 9 can be formed by the same method as the first dam 8. The provision of the second dam 9 makes it possible to prevent the filling material from leaking not only outside but also inside.

[0028] The first dam 8 and the second dam 9 are both provided in the area where the first electrode structure 3 and the metal frame 7 overlap. The first dam 8 and the second dam 9 are spaced apart. That is, the width of the first dam 8 itself and the width of the second dam 9 itself are each smaller than 0.5 times the width of the area where the first electrode structure 3 and the metal frame 7 overlap.

[0029] The first dam 8 is preferably provided at a depth that extends from the surface (lower surface) of the first electrode structure 3 to the electrolyte layer 2. By providing the first dam 8 at such a depth, leakage of the filler material is more reliably prevented.

[0030] On the other hand, the second dam 9 is preferably provided at a shallower depth from the surface of the first electrode structure 3 than the first dam 8. In other words, the second dam 9 preferably does not reach the electrolyte layer 2. The deeper the dam, the easier it is to prevent leakage of the filler material. However, if the second dam 9 is formed deep enough to reach the electrolyte layer 2, the electrolyte layer 2 may be damaged. As a result, gas may leak through the damaged area. In contrast, if the second dam 9 is deep enough not to reach the electrolyte layer 2, damage to the electrolyte layer 2 is prevented. Therefore, gas leakage due to damage to the electrolyte layer 2 is prevented.

[0031] The first dam 8 is located in a region surrounded by the filling portion 11 and the sealing material 6. Therefore, even if the electrolyte layer 2 is damaged above the first dam 8, there is little concern about gas leakage through the damaged area. Therefore, from the viewpoint of more reliably preventing leakage of the filling material, the first dam 8 is preferably provided at a depth that reaches the electrolyte layer 2, as described above.

[0032] Next, the welded portion 10 will be described. As described above, the stack 5 is joined to the metal frame 7 by the welded portion 10. Here, the welded portion 10 is formed so as to have a ring shape when viewed along the stacking direction. Furthermore, the welded portion 10 is provided in the filling portion 11. That is, the welded portion 10 is provided between the first dam 8 and the second dam 9. By providing the welded portion 10 in such a position, it is possible to prevent gas from leaking to the outside through the interface between the first electrode structure 3 and the metal frame 7. Furthermore, when the filling portion 11 is filled with metal as a filler, the weld bead constituting the welded portion 10 becomes denser in the filling portion 11. Therefore, the gas is more reliably sealed in the welded portion 10.

[0033] Next, the configuration of the second electrode structure 4 will be described.

[0034] As shown in FIG. 2 , the second porous metal support layer 4-2 is not provided on the outer periphery of the second electrode structure 4. That is, when viewed along the stacking direction, the outer shape of the second porous metal support layer 4-2 is located inside the outer shapes of the second electrode layer 4-1 and the electrolyte layer 2. As a result, the second electrode layer 4-1 is exposed on the outer periphery of the laminate 5. A sealant 6 is provided to cover the exposed portion of the second electrode layer 4-1 and the end of the laminate 5. The exposed portion of the second electrode layer 4-1 is formed by removing the second porous metal support layer 4-2 by etching or the like, and is rougher than the surface of the second porous metal support layer 4-2. This configuration allows the sealant 6 to firmly adhere to the exposed portion of the second electrode layer 4-1 by an anchor effect.

[0035] In the example shown in FIG. 2, the second electrode layer 4-1 is exposed at the outer periphery, but the electrolyte layer 2 may be exposed instead of the second electrode layer 4-1, and the exposed portion of the electrolyte layer 2 may be covered with the sealing material 6.

[0036] The above has described the configuration of the solid oxide fuel cell 1 according to the first embodiment. In the above example, the configuration of the battery cell of the solid oxide fuel cell 1 has been described, but the solid oxide fuel cell 1 may also be provided as a battery module in which a plurality of battery cells are stacked.

[0037] Next, an example of a method for manufacturing the solid oxide fuel cell 1 according to this embodiment will be described. Figures 3 to 7 are schematic cross-sectional views showing the solid oxide fuel cell 1 during the manufacturing process.

[0038] (Step S1) Preparation of green sheet laminate First, as shown in FIG. 3, a green sheet laminate 5′ is prepared by laminating a green sheet 3′ for the first electrode structure, a green sheet 2′ for the electrolyte layer, and a green sheet 4′ for the second electrode structure. The green sheet 3′ for the first electrode structure includes a green sheet 3-2′ for the first porous metal support layer and a green sheet 3-1′ for the first electrode layer. The green sheet 4′ for the second electrode structure includes a green sheet 4-2′ for the second porous metal support layer and a green sheet 4-1′ for the second electrode layer. The green sheet laminate 5′ can be formed, for example, by tape casting. Specifically, first, a slurry containing the raw materials for each layer to be included in the laminate is prepared. Then, each prepared slurry is formed into a sheet. This results in a green sheet for each layer. The obtained green sheets are then stacked. This results in a green sheet laminate 5′.

[0039] (Step S2) Firing Next, the green sheet laminate 5' is fired. This results in a fired laminate in which the first porous metal support layer 3-2, the first electrode layer 3-1, the electrolyte layer 2, the second electrode layer 4-1, and the second porous metal support layer 4-2 are stacked in this order. Note that, since the fired laminate has a symmetrical structure with the electrolyte layer 2 sandwiched therebetween, warping of the laminate 5 during firing can be prevented.

[0040] (Step S3) Forming exposed parts Next, as shown in FIG. 4, at least a portion of the second electrode structure 4 is removed from the periphery of the sintered laminate to expose the second electrode layer 4-1 or the electrolyte layer 2. This forms an exposed portion 12. The second electrode structure 4 can be chemically removed, for example, by etching using a solution (e.g., acid). Alternatively, the second electrode structure 4 may be removed by mechanical processing. The exposed portion 12 thus formed has a surface roughness greater than that of the second porous metal support layer 4-2. Therefore, when a sealing material 6 is formed in a subsequent process, the sealing material 6 can be firmly bonded to the laminate 5 due to the anchor effect.

[0041] (Step S4) Dam formation 5, the first dam 8 and the second dam 9 are formed on the first electrode structure 3. As described above, the first dam 8 and the second dam 9 can be formed by wire electric discharge machining, laser welding beads, or the like. In this case, as described above, the first dam 8 is preferably formed to a depth that reaches the electrolyte layer 2. The second dam 9 is preferably formed to a depth that does not reach the electrolyte layer 2.

[0042] (Step S5) Formation of filling part 6, a filler material is supplied between the first dam 8 and the second dam 9 to form a filled portion 11. At this time, the presence of the first dam 8 and the second dam 9 prevents the filler material from unintentionally leaking outside the first dam 8 or inside the second dam 9.

[0043] When metal powder is used as the filler, the metal can be filled into the pores by, for example, placing the metal powder in a predetermined location and melting the metal powder using an LMD (Laser Metal Deposition) method. When glass is used as the filler, the glass can be filled into the pores by melting it through calcination. When ceramics is used as the filler, the filling portion 11 can be formed, for example, by supplying a liquid containing powdered ceramics between the first dam 8 and the second dam 9 and then firing it.

[0044] As already mentioned, the filler is preferably supplied to a depth that reaches the electrolyte layer 2.

[0045] (Step S6) Joining the metal frame 7 and the laminate 5 Next, as shown in Fig. 7, the laminate 5 is placed on the metal frame 7. Then, the filling portion 11 and the metal frame 7 are joined by welding. This forms a welded portion 10, and the laminate 5 is fixed to the metal frame 7. The welded portion 10 can be formed by, for example, laser welding or brazing.

[0046] (Step S7) Formation of sealing material 6 Next, a sealing material 6 is formed so as to cover the exposed portion 12 and the end portion of the laminate 5. This results in a solid oxide fuel cell having the structure shown in Figures 1 and 2. At this time, as described above, the exposed portion 12 has a rough surface, so that the sealing material 6 can be firmly bonded to the laminate 5 by an anchor effect.

[0047] When glass is used as the sealing material 6, for example, glass powder can be placed in the position where the sealing material 6 is to be formed and melted by heating to form the sealing material 6. Alternatively, the sealing material 6 can be formed by preparing a binder resin in which glass powder is dispersed, applying this binder resin to a predetermined position on the laminate 5, and firing the binder resin. Alternatively, the sealing material 6 can be formed by placing a green sheet containing glass powder in a predetermined position and firing the green sheet.

[0048] According to the above-described method, the green sheet laminate 5' is fired all at once in steps S1 and S2. Then, the exposed portion 12, the first dam 8, the second dam 9, and the filled portion 11 are formed. According to such a method, it is not necessary to perform separate firing steps for forming each layer, and only one firing step is required, thereby minimizing the cost required for firing.

[0049] In the above example, the case has been described where the exposed portion 12 is formed in step S3, and then the dam and the filling portion 11 are formed in steps S4 and S5. However, the order of these steps is not limited to this. For example, the exposed portion 12 may be formed after the first dam 8, the second dam 9, and the filling portion 11 are formed.

[0050] The first embodiment has been described above. The following summarizes the representative configuration and effects of this embodiment.

[0051] According to this embodiment, a solid oxide fuel cell 1 includes a porous first electrode structure 3, an electrolyte layer 2 stacked on the first electrode structure 3, and a second electrode structure 4 stacked on the electrolyte layer 2. The first electrode structure 3 includes a first porous metal support layer 3-2 and a first electrode layer 3-1 disposed between the first porous metal support layer 3-2 and the electrolyte layer 2. The first electrode structure 3 includes a filling section 11, which is a region in which pores are filled with a filler and is provided so as to have a ring shape when viewed along the stacking direction, and a first dam 8, which is located outside the filling section 11 when viewed along the stacking direction and is a densified portion to prevent the filler from leaking outside the filling section 11. By adopting this configuration, even if the filler in the filling section 11 softens at high temperatures, the softened filler is blocked by the first dam 8. Therefore, gas sealing performance is maintained even at high temperatures and high internal pressures.

[0052] In a preferred embodiment, the first electrode structure 3 further includes a second dam 9, which is provided inside the filling section 11 when viewed along the stacking direction and is a densified portion to prevent the filler from leaking inside the filling section 11. By adopting such a configuration, the filler is blocked by the second dam 9 when filling the filling section 11, thereby preventing the filler from unintentionally leaking inside. In addition, it is also possible to prevent the softened filler from leaking inside during operation.

[0053] In a preferred embodiment, the first dam 8 is provided at a depth from the surface of the first electrode structure 3 to the electrolyte layer 2. The second dam 9 is provided at a depth from the surface of the first electrode structure 3 that is shallower than the first dam 8. With this configuration, the first dam 8 is provided at a depth that reaches the electrolyte layer 2, which more reliably prevents the filler from leaking to the outside. Furthermore, the second dam 9 does not reach the electrolyte layer 2, which prevents the electrolyte layer 2 from being damaged. This prevents gas leakage between the two electrodes through a damaged electrolyte layer 2.

[0054] In a preferred embodiment, a metal frame 7 is provided below the first electrode structure 3. The first electrode structure 3 is joined to the metal frame 7 at the filling portion 11. More preferably, the first electrode structure 3 is joined to the metal frame 7 by welding. By employing such a configuration, the first electrode structure 3 can be firmly joined to the metal frame 7, thereby increasing the mechanical strength.

[0055] In a preferred embodiment, the filling section 11 is provided to a depth that reaches from the surface of the first electrode structure 3 to the electrolyte layer 2. By employing such a configuration, leakage of the gas supplied to the first electrode structure 3 is more reliably prevented.

[0056] In a preferred embodiment, the second electrode structure 4 has a second porous metal support layer 4-2 and a second electrode layer 4-1 provided between the second porous metal support layer 4-2 and the electrolyte layer 2. With this configuration, a metal support layer is also provided on the second electrode structure 4 side, so that the laminate 5 has a symmetrical structure with respect to the electrolyte layer 2. This symmetrical structure can reduce warpage of the laminate 5 when the green sheet laminate 5' is fired.

[0057] In a preferred embodiment, the solid oxide fuel cell 1 further includes a sealing material 6. An exposed portion 12 where the second electrode layer 4-1 or the electrolyte layer 2 is exposed is provided on the outer periphery on the second electrode structure 4 side. The sealing material 6 is provided so as to cover the end of the laminate 5 and the exposed portion 12. With this configuration, the sealing material 6 is bonded to the second electrode layer 4-1 or the electrolyte layer 2 at the exposed portion 12, so that the sealing material 6 can be firmly bonded to the end of the laminate 5.

[0058] The method for manufacturing a solid oxide fuel cell 1 according to this embodiment includes the steps of: preparing a green sheet laminate 5′ by stacking a green sheet 3′ for a first electrode structure, a green sheet 2′ for an electrolyte layer, and a green sheet 4′ for a second electrode structure; firing the green sheet laminate 5′ to prepare a fired laminate; and, after the step of preparing the fired laminate, forming a first dam 8 on the first electrode structure 3 so that the first dam 8 has a ring shape when viewed along the stacking direction; and supplying a filler material to the first electrode structure 3 in a region inside the first dam 8 when viewed along the stacking direction to form a filling portion 11. This method requires only one firing step to obtain the laminate 5, thereby reducing the cost required for firing.

[0059] In a preferred embodiment, the manufacturing method according to the present embodiment further includes, after the step of producing the fired laminate, a step of forming an annular second dam 9 in a region that is inside the first dam 8 when viewed along the stacking direction. The step of forming the filling portion 11 includes a step of supplying a filler material between the first dam 8 and the second dam 9. According to this method, the filler material is blocked by the first dam 8 and the second dam 9 when being filled. This prevents the filler material from leaking into unintended regions during manufacturing.

[0060] In a preferred embodiment, the second electrode structure 4 includes a second porous metal support layer 4-2 and a second electrode layer 4-1 disposed between the second porous metal support layer 4-2 and the electrolyte layer 2. After preparing the sintered laminate, at least a portion of the second electrode structure 4 is removed from the periphery of the sintered laminate to expose the second electrode layer 4-1 or the electrolyte layer 2, forming an exposed portion 12. A sealing material 6 is also formed to cover the exposed portion 12 and the edge of the sintered laminate. This method allows the exposed portion 12 with a rough surface to be formed by removing a portion of the protruding portion of the second electrode structure 4 after sintering. Bonding the sealing material 6 to the exposed portion 12 provides an anchor effect, allowing the sealing material 6 to be firmly bonded to the laminate 5. Furthermore, the exposed portion 12 can be formed by processing the sintered laminate after sintering the green sheet laminate 5′. Forming the exposed portion 12 through simple processing is advantageous in terms of manufacturing costs.

[0061] [Second embodiment] Next, a second embodiment will be described. In this embodiment, the configuration of the filling section 11 is further improved. Note that, in this embodiment, the same configuration as in the first embodiment can be adopted, and therefore a description thereof will be omitted.

[0062] 8 is a schematic cross-sectional view showing an end portion of a solid oxide fuel cell 1 according to this embodiment. In this embodiment, the first electrode layer 3-1 is a porous ceramic layer. The pore diameter of the first electrode layer 3-1 is smaller than the pore diameter of the first porous metal support layer 3-2. The filling section 11 is provided at a depth that reaches from the surface (lower surface) of the first electrode structure 3 to the electrolyte layer 2.

[0063] In the above-described configuration, the first electrode structure 3 has two layers with different pore diameters, making it difficult to uniformly fill both layers with filler. Therefore, in this embodiment, the following measures are taken.

[0064] That is, in this embodiment, the filling section 11 has a first filling section 11-1 and a second filling section 11-2.

[0065] The first filling section 11-1 is a region where the pores in the first electrode layer 3-1 are filled. The first filling section 11-1 is filled with first particles as a filler. The first particles have a particle size smaller than the pore size of the first electrode layer 3-1. Ceramic particles such as ceria are used as the first particles.

[0066] On the other hand, the second filling section 11-2 is a region where the pores in the first porous metal support layer 3-2 are filled. The second filling section 11-2 is filled with second particles as a filler. The second particles have a larger particle size than the first particles. However, the particle size of the second particles is smaller than the pore size of the first porous metal support layer 3-2.

[0067] As described above, in this embodiment, the first electrode layer 3-1, which has a small pore size, is filled with first particles having a small particle size. The first porous metal support layer 3-2, which has a large pore size, is filled with second particles having a large particle size. Because particles having a particle size corresponding to the pore size are used as the filler, the filler can be densely packed throughout the entire filling portion 11.

[0068] Furthermore, the second filling section 11-2 is filled with a mixture of ceramic and metal (cermet) as second particles. The ratio of ceramic to metal in the filling material varies in the depth direction of the second filling section 11-2. Specifically, the ratio of ceramic to metal is higher in a position close to the first electrode layer 3-1 (region A in the figure), and lower in a position close to the metal frame 7 (region B in the figure) than in region A (the ratio of metal is higher than in region A).

[0069] As described above, the first electrode layer 3-1 is made of ceramic. In this embodiment, the proportion of ceramic is higher in a position closer to the first electrode layer 3-1, which increases the affinity between the second filling portion 11-2 and the first electrode layer 3-1. On the other hand, the proportion of metal is higher in a position closer to the metal frame 7, which increases the affinity between the second filling portion 11-2 and the metal frame 7 and makes it easier to form the weld 10.

[0070] Next, a method for manufacturing the solid oxide fuel cell 1 according to this embodiment will be described. The solid oxide fuel cell 1 according to this embodiment can be obtained by modifying the processing of the step of forming the filling section 11 (step S5) in the first embodiment.

[0071] Specifically, in this embodiment, the first electrode layer 3-1 is impregnated in advance with a liquid (slurry) containing first particles as a filler, thereby filling the pores of the first electrode layer 3-1 with the first particles. Filling with the first particles may be performed at any stage after the firing of the green sheet laminate (step S2). For example, after firing the green sheet laminate 5′ and before the formation of the exposed portion 12, a liquid containing the first particles is supplied to the outer periphery of the first electrode structure 3. At this time, a liquid having a viscosity that allows the liquid to permeate the first porous metal support layer 3-2 is used as the liquid containing the first particles. This allows the liquid containing the first particles to permeate the first porous metal support layer 3-2 and reach the first electrode layer 3-1. Thereafter, a heating treatment or the like is performed as necessary to remove the solvent. This allows the first particles to fill the pores of the first electrode layer 3-1, thereby forming first filling portions 11-1 in the first electrode layer 3-1.

[0072] After the first dam 8 and the second dam are formed (after step S4), a mixture of metal and ceramic is filled between the first dam 8 and the second dam 9 as second particles. The second particles are supplied between the first dam 8 and the second dam 9, for example, dispersed in a binder or the like. After supplying, if necessary, firing or the like is performed to remove the binder or the like. At this time, a raw material with a high ratio of ceramic to metal is first supplied. Next, a raw material with a low ratio of ceramic to metal is filled. This allows the second filling section 11-2 to be formed so that the ratio of ceramic to metal varies in the depth direction.

[0073] As described above, in this embodiment, the filling section 11 is provided at a depth that extends from the surface of the first electrode structure 3 to the electrolyte layer 2. Furthermore, the pore diameter in the first electrode layer 3-1 is smaller than the pore diameter in the first porous metal support layer 3-2. In the filling section 11, the first electrode layer 3-1 is filled with first particles as a filler, and the first porous metal support layer 3-2 is filled with second particles having a larger particle diameter than the first particles as a filler. Because particles having a particle diameter corresponding to the pore diameter are filled, the filler can be densely filled throughout the entire filling section 11, despite the difference in pore diameter between the first electrode layer 3-1 and the first porous metal support layer 3-2.

[0074] Furthermore, according to this embodiment, the first electrode layer 3-1 is a porous ceramic layer. In addition, in the filling section 11, the first porous metal support layer 3-2 is filled with a mixture of ceramic and metal as a filler. The ratio of ceramic to metal in the filler filled in the first porous metal support layer 3-2 is high in a position close to the first electrode layer 3-1 and low in a position close to the metal frame 7. This configuration can increase the affinity between the second filling section 11-2 and the first electrode layer 3-1. Furthermore, the affinity between the metal frame 7 and the filling section 11 can also be increased, making welding easier.

Claims

1. a porous first electrode structure; an electrolyte layer laminated on the first electrode structure; a second electrode structure laminated on the electrolyte layer; Equipped with The first electrode structure is a first porous metal support layer; a first electrode layer disposed between the first porous metal support layer and the electrolyte layer; The first electrode structure includes: a filling portion that is a region where the pores are filled with a filler and is provided so as to have an annular shape when viewed along the stacking direction; a ring-shaped first dam that is located outside the filling portion when viewed along the stacking direction and is a densified portion that prevents the filling material from leaking outside the filling portion; a ring-shaped second dam that is provided inside the filling portion when viewed along the stacking direction and is a densified portion that prevents the filling material from leaking into the filling portion; are provided, Solid oxide fuel cell.

2. 2. The solid oxide fuel cell according to claim 1, the first dam is provided at a depth that reaches the electrolyte layer from a surface of the first electrode structure, the second dam is provided at a shallower depth from the surface of the first electrode structure than the first dam; Solid oxide fuel cell.

3. 2. The solid oxide fuel cell according to claim 1, The semiconductor device further includes a metal frame provided below the first electrode structure, the first electrode structure is joined to the metal frame at the filling portion; Solid oxide fuel cell.

4. 4. The solid oxide fuel cell according to claim 3, the first electrode structure is joined to the metal frame by welding; Solid oxide fuel cell.

5. 5. The solid oxide fuel cell according to claim 4, the first electrode layer is a porous ceramic layer, In the filling section, the first porous metal support layer is filled with a mixture of ceramics and metal as the filler, a ratio of ceramic to metal in the filler filled in the first porous metal support layer is large at a position close to the first electrode layer and is small at a position close to the metal frame; Solid oxide fuel cell.

6. 2. The solid oxide fuel cell according to claim 1, the filling portion is provided to a depth that reaches from the surface of the first electrode structure to the electrolyte layer. Solid oxide fuel cell.

7. 7. The solid oxide fuel cell according to claim 6, the pore size in the first electrode layer is smaller than the pore size in the first porous metal support layer; In the filling section, the first electrode layer is filled with first particles as the filler, and the first porous metal support layer is filled with second particles having a particle size larger than that of the first particles as the filler. Solid oxide fuel cell.

8. 2. The solid oxide fuel cell according to claim 1, The second electrode structure is a second porous metal support layer; a second electrode layer provided between the second porous metal support layer and the electrolyte layer; Solid oxide fuel cell.

9. 9. The solid oxide fuel cell according to claim 8, Further, the device has a sealing material, an exposed portion in which the second electrode layer or the electrolyte layer is exposed is provided at an outer periphery of the electrolyte layer on the second electrode structure side, the sealing material is provided so as to cover an end portion of a stacked body including the first electrode structure, the electrolyte layer, and the second electrode structure, and the exposed portion. Solid oxide fuel cell.

10. A method for producing the solid oxide fuel cell according to claim 1, comprising: a step of preparing a green sheet laminate in which a green sheet for the first electrode structure, a green sheet for the electrolyte layer, and a green sheet for the second electrode structure are laminated; firing the green sheet laminate to produce a fired laminate including the first electrode structure, the electrolyte layer, and the second electrode structure; After the step of preparing the fired laminate, forming the first dam on the first electrode structure so as to have a ring shape when viewed along the lamination direction; supplying the filler material to the first electrode structure in a region inside the first dam when viewed along the stacking direction to form the filling portion; Manufacturing method.

11. The method of claim 10, Furthermore, forming a ring-shaped second dam in a region that is inside the first dam when viewed along the stacking direction after the step of producing the fired stacked body; forming the filling portion includes supplying the filling material between the first dam and the second dam; Manufacturing method.

12. The method of claim 10, The second electrode structure is a second porous metal support layer; a second electrode layer disposed between the second porous metal support layer and the electrolyte layer, The manufacturing method further comprises: After the step of preparing the fired laminate, a step of removing at least a portion of the second electrode structure at an outer periphery of the fired laminate so as to expose the second electrode layer or the electrolyte layer, thereby forming an exposed portion; and forming a sealant to cover the exposed portion and an end portion of the fired laminate. Manufacturing method.

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