Electrochemical cell, electrochemical cell device, module, and module housing device

Abstract

This electrochemical cell comprises a porous portion, a metal member, a sealing material, and an intermediate material. The porous portion is electrically conductive. The metal member contains chromium. The sealing material is positioned on the porous portion and on the metal member. The intermediate material is positioned between the metal member and the sealing material. The intermediate material has two or more parts in different positions having different surface roughnesses or thicknesses.

Description

Technical Field

[0001] The present disclosure relates to an electrochemical cell, an electrochemical cell device, a module, and a module housing device.

Background Art

[0002] In recent years, various fuel cell stack devices having a plurality of fuel cells have been proposed as next-generation energy. A fuel cell is a type of electrochemical cell that can obtain electric power using a fuel gas such as a hydrogen-containing gas and an oxygen-containing gas such as air.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

[0004] An electrochemical cell according to one aspect of the embodiment includes a porous part, a metal member, a sealing material, and an intermediate material. The porous part has conductivity. The metal member contains chromium. The sealing material is located on the porous part and the metal member. The intermediate material is located between the metal member and the sealing material. The intermediate material has two or more portions with different surface roughnesses or thicknesses at different positions.

[0005] An electrochemical cell according to one aspect of the embodiment includes a porous part, a metal member, a sealing material, and an intermediate material. The porous part has conductivity. The metal member contains chromium. The sealing material is located on the porous part and the metal member. The intermediate material is located between the metal member and the sealing material. The surface roughness of the first interface of the intermediate material facing the sealing material is different from the surface roughness of the second interface of the intermediate material facing the metal member.

[0006] An electrochemical cell according to one aspect of the embodiment includes a porous part, a metal member, a sealing material, and an intermediate material. The porous part has conductivity. The metal member contains chromium. The sealing material is located on the porous part and the metal member. The intermediate material is located between the metal member and the sealing material. At least one element of Mn, Ti, Ca, and Al is located at the boundary between the metal member and the intermediate material. A first content rate, which is the total content rate of Mn, Ti, Ca, and Al at the boundary, is different from a second content rate, which is the total content rate of Mn, Ti, Ca, and Al inside the metal member or inside the intermediate material.

[0007] In addition, an electrochemical cell device of the present disclosure has a cell stack including the electrochemical cell described above.

[0008] In addition, a module of the present disclosure includes the electrochemical cell device described above and a storage container for storing the electrochemical cell device.

[0009] In addition, a module housing device of the present disclosure includes the module described above, auxiliary equipment for operating the module, and an exterior case for housing the module and the auxiliary equipment.

Brief Description of the Drawings

[0010]

Figure 1A

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Best Mode for Carrying Out the Invention

[0011] In the above fuel cell stack device, for example, it has a metal member that supports a plurality of fuel cells. In such a structure, there is room for improvement in the durability of the joint portion that fixes the metal member and seals the gas.

[0012] Therefore, there is an expectation for providing an electrochemical cell, an electrochemical cell device, a module, and a module housing device with high durability.

[0013] Hereinafter, with reference to the accompanying drawings, embodiments of the electrochemical cell, electrochemical cell device, module, and module housing device disclosed in the present application will be described in detail. Note that this disclosure is not limited by the embodiments shown below.

[0014] Also, note that the drawings are schematic, and it is necessary to be aware that the dimensional relationships between elements, the ratios of the elements, etc. may be different from reality. Furthermore, even between the drawings, there may be parts where the dimensional relationships and ratios between each other are different.

[0015] [First Embodiment] [Configuration of the Cell] First, with reference to FIGS. 1A to 1C, as an electrochemical cell according to the first embodiment, an example of a solid oxide type fuel cell will be used for explanation. The electrochemical cell device may include a cell stack having a plurality of electrochemical cells. An electrochemical cell device having a plurality of electrochemical cells is simply referred to as a cell stack device.

[0016] FIG. 1A is a cross-sectional view showing an example of an electrochemical cell according to the first embodiment, FIG. 1B is a side view of an example of an electrochemical cell according to the first embodiment as viewed from the air electrode side, and FIG. 1C is a side view of an example of an electrochemical cell according to the first embodiment as viewed from the interconnector side. Note that FIGS. 1A to 1C show a partial enlargement of each configuration of the electrochemical cell. Hereinafter, the electrochemical cell may also be simply referred to as a cell.

[0017] In the example shown in FIGS. 1A to 1C, the cell 1 is a hollow flat plate type and is an elongated plate shape. As shown in FIG. 1B, the shape of the entire cell 1 as viewed from the side is, for example, a rectangle with the length of the side in the length direction L being 5 cm to 50 cm and the length in the width direction W orthogonal to this length direction L being 1 cm to 10 cm. The thickness in the thickness direction T of the entire cell 1 is, for example, 1 mm to 5 mm.

[0018] As shown in FIG. 1A, the cell 1 includes a support substrate 2, an element portion 3, an interconnector 4, an adhesive 9, an intermediate material 24, and a sealing material 25. The support substrate 2 is columnar and has a pair of opposing flat surfaces n1, n2, and a pair of arcuate side surfaces m connecting such flat surfaces n1, n2.

[0019] The element portion 3 is located on the flat surface n1 of the support substrate 2. Such an element portion 3 has a fuel electrode 5, a solid electrolyte layer 6, and an air electrode 8. Also, in the example shown in FIG. 1A, the interconnector 4 is located on the flat surface n2 of the cell 1. Note that the cell 1 may include an intermediate layer 7 between the solid electrolyte layer 6 and the air electrode 8.

[0020] Also, as shown in FIG. 1B, the air electrode 8 does not extend to the upper and lower ends of the cell 1. At the lower end portion of the cell 1, only the solid electrolyte layer 6 is exposed on the surface. Also, as shown in FIG. 1C, the interconnector 4 may extend to the lower end of the cell 1. At the lower end portion of the cell 1, the interconnector 4 and the solid electrolyte layer 6 are exposed on the surface. Both end portions in the width direction W of the interconnector 4 are gas-sealed with the sealing material 25. Note that, as shown in FIG. 1A, the solid electrolyte layer 6 is exposed on the surface of the pair of arcuate side surfaces m of the cell 1. The interconnector 4 does not have to extend to the lower end of the cell 1.

[0021] Hereinafter, each constituent member constituting the cell 1 will be described.

[0022] The support substrate 2 has a gas flow path 2a inside through which gas flows. The example of the support substrate 2 shown in FIG. 1A has six gas flow paths 2a. The support substrate 2 has gas permeability and allows the fuel gas flowing through the gas flow path 2a to permeate to the fuel electrode 5. The support substrate 2 has electrical conductivity. The conductive support substrate 2 collects the electricity generated in the element part 3 and conducts it to the interconnector 4.

[0023] The material of the support substrate 2 includes, for example, an iron group metal component and an inorganic oxide. The iron group metal component may be, for example, Ni (nickel) and / or NiO. The inorganic oxide may be, for example, a specific rare earth element oxide. The rare earth element oxide may contain, for example, Y.

[0024] As the material of the fuel electrode 5, generally known materials can be used. The fuel electrode 5 may be made of a porous conductive ceramic, such as a ceramic containing an ion-conductive material such as ZrO2 in which a rare earth element oxide is dissolved, and Ni and / or NiO. This rare earth element oxide contains, for example, a plurality of rare earth elements selected from Sc, Y, La, Nd, Sm, Gd, Dy, and Yb. ZrO2 in which a rare earth element oxide is dissolved is sometimes referred to as stabilized zirconia. Stabilized zirconia also includes partially stabilized zirconia.

[0025] The solid electrolyte layer 6 is an electrolyte and transfers ions between the fuel electrode 5 and the air electrode 8. At the same time, the solid electrolyte layer 6 has gas barrier properties and makes it difficult for the fuel gas and the oxygen-containing gas to leak. exists.

[0026] The material of the solid electrolyte layer 6 may be, for example, an ion conductive material such as ZrO2 in which 3 mol% to 15 mol% of rare earth element oxides are solid-solved. The rare earth element oxide may contain, for example, one or more rare earth elements selected from Sc, Y, La, Nd, Sm, Gd, Dy, and Yb. The solid electrolyte layer 6 may contain, for example, ZrO2 in which Yb, Sc, or Gd is solid-solved, may contain CeO2 in which La, Nd, or Yb is solid-solved, may contain BaZrO3 in which Sc or Yb is solid-solved, or may contain BaCeO3 in which Sc or Yb is solid-solved.

[0027] The air electrode 8 has gas permeability. The open porosity (void fraction) of the air electrode 8 may be, for example, in the range of 20% to 50%, particularly 30% to 50%.

[0028] The material of the air electrode 8 is not particularly limited as long as it is generally used for air electrodes. The material of the air electrode 8 may be, for example, a conductive ceramic such as a so-called ABO3-type perovskite oxide.

[0029] The material of the air electrode 8 may be, for example, a composite oxide in which Sr (strontium) and La (lanthanum) coexist at the A site. Examples of such composite oxides include La x Sr 1-x Co y Fe 1-y O3, La x Sr 1-x MnO3, La x Sr 1-x FeO3, La x Sr 1-x CoO3, etc. Here, x is 0 < x < 1, and y is 0 < y < 1.

[0030] When the element portion 3 has the intermediate layer 7, the intermediate layer 7 has a function as a diffusion suppression layer. The intermediate layer 7 makes it difficult for Sr (strontium) contained in the air electrode 8 to diffuse into the solid electrolyte layer 6 containing Zr, for example, and thus makes it difficult to form a resistance layer of SrZrO3 in such a solid electrolyte layer 6.

[0031] The material of the intermediate layer 7 is not particularly limited as long as it generally makes it difficult for elements to diffuse between the air electrode 8 and the solid electrolyte layer 6. The material of the intermediate layer 7 may include, for example, cerium oxide (CeO2) in which rare earth elements excluding Ce (cerium) are solid-dissolved. As such rare earth elements, for example, Gd (gadolinium), Sm (samarium), etc. may be used.

[0032] The interconnector 4 is a dense metal member and hardly causes leakage of the fuel gas flowing through the gas flow path 2a inside the support substrate 2 and the oxygen-containing gas flowing outside the support substrate 2. The interconnector 4 is fixed to the support substrate 2 having the gas flow path 2a by an adhesive 9.

[0033] The interconnector 4 contains chromium. The interconnector 4 is, for example, stainless steel. The interconnector 4 may be, for example, stainless steel such as high heat-resistant ferritic stainless steel or austenitic stainless steel. The interconnector 4 may be, for example, a nickel-chromium alloy or an iron-chromium alloy. The interconnector 4 may contain, for example, a metal oxide. Such an interconnector 4 is an example of a metal member.

[0034] The adhesive 9 is located between the interconnector 4 and the support substrate 2. The adhesive 9 has conductivity. The adhesive 9 may have, for example, gas permeability.

[0035] The adhesive 9 may contain, for example, conductive particles such as Ni. The adhesive 9 may contain inorganic oxides such as TiO2, rare earth element oxides (Y2O3, CeO2, etc.), and transition metal oxides (Fe2O3, CuO, etc.).

[0036] The sealing material 25 is located on the end face of the interconnector 4. The sealing material 25 is located so as to straddle the interconnector 4 and the solid electrolyte layer 6 and seals the flow of the fuel gas between the fuel electrode 5, the adhesive 9, and the outside.

[0037] The sealing material 25 has electrical insulation properties. Hereinafter, electrical insulation properties may sometimes be simply referred to as insulation properties. As the sealing material 25, for example, oxides with low conductivity such as glass can be used. The material of the sealing material 25 may be, for example, amorphous glass or crystallized glass. As the crystallized glass, for example, any of materials such as SiO2-CaO system, MgO-B2O3 system, La2O3-B2O3-MgO system, La2O3-B2O3-ZnO system, SiO2-CaO-ZnO system may be used, and in particular, a material of SiO2-MgO system may be used.

[0038] The intermediate material 24 is located between the interconnector 4 and the sealing material 25. The intermediate material 24 may contain, for example, an insulating oxide such as forsterite that has higher heat resistance than the sealing material 25. Thereby, since the intermediate material 24 enhances the adhesion between the sealing material 25 and the interconnector 4, the durability of the cell 1 can be enhanced. The insulating oxide may have, for example, an electrical resistivity of 1×10 10 Ω·m or more at room temperature. Also, compared with the sealing material 25, the intermediate material 24 is less likely to cause dissolution or evaporation of components in high-temperature steam, so gas leakage and deterioration of electrode performance are less likely to occur. The intermediate material 24 contains an oxide that is less likely to cause desorption into the oxidation atmosphere of chromium contained in the interconnector 4.

[0039] FIG. 1D is a cross-sectional view showing another example of the electrochemical cell according to the first embodiment. In the example shown in FIG. 1D, unlike the example shown in FIG. 1A, the length of the interconnector 4 in the width direction W is larger than the length of the cell 1 in the width direction W. In the example shown in FIG. 1D, the configuration other than the above points is applied to the configuration in the example of FIG. 1A.

[0040] <Configuration of the cell stack device> Next, the cell stack device according to the present embodiment using the above-described cell 1 will be described with reference to FIGS. 2A to 2C. FIG. 2A is a perspective view showing an example of the cell stack device according to the embodiment, FIG. 2B is a cross-sectional view taken along the line X-X shown in FIG. 2A, and FIG. 2C is a top view showing an example of the cell stack device according to the embodiment.

[0041] As shown in FIG. 2A, the cell stack device 10 includes a cell stack 11 having a plurality of cells 1 arranged (stacked) in the thickness direction T (see FIG. 1A) of the cell 1, and a fixing member 12.

[0042] The fixing member 12 has a fixing material 13 and a support member 14. The support member 14 supports the cell 1. The fixing material 13 fixes the cell 1 to the support member 14. Further, the support member 14 has a support body 15 and a gas tank 16. The support body 15 and the gas tank 16, which are the support members 14, are made of metal and have conductivity.

[0043] As shown in FIG. 2B, the support body 15 has insertion holes 15a into which the lower ends of the plurality of cells 1 are inserted. The lower ends of the plurality of cells 1 and the inner wall of the insertion holes 15a are joined by a fixing material 13.

[0044] The gas tank 16 has an opening for supplying a reaction gas to the plurality of cells 1 through the insertion holes 15a, and a concave groove 16a located around such an opening. The end of the outer periphery of the support body 15 is joined to the gas tank 16 by a joining material 21 filled in the concave groove 16a of the gas tank 16.

[0045] In the example shown in FIG. 2A, fuel gas is stored in an internal space 22 formed by the support body 15 and the gas tank 16, which are the support members 14. A gas flow pipe 20 is connected to the gas tank 16. The fuel gas is supplied to the gas tank 16 through this gas flow pipe 20, and is supplied from the gas tank 16 to the gas flow path 2a (see FIG. 1A) inside the cell 1. The fuel gas supplied to the gas tank 16 is generated by a reformer 102 (see FIG. 7) described later.

[0046] A hydrogen-rich fuel gas can be generated by steam reforming or the like of a raw fuel. When generating a fuel gas by steam reforming, the fuel gas contains steam.

[0047] In the example shown in FIG. 2A, it includes two columns of cell stacks 11, two supports 15, and a gas tank 16. The two columns of cell stacks 11 each have a plurality of cells 1. Each cell stack 11 is fixed to each support 15. The gas tank 16 has two through holes on its upper surface. Each support 15 is disposed in each through hole. The internal space 22 is formed by one gas tank 16 and two supports 15.

[0048] The shape of the insertion hole 15a is, for example, oval in top view. The insertion hole 15a is such that, for example, the length in the arrangement direction of the cells 1, that is, the thickness direction T, is larger than the distance between the two end current collecting members 17 located at both ends of the cell stack 11. The width of the insertion hole 15a is, for example, larger than the length in the width direction W (see FIG. 1A) of the cells 1.

[0049] As shown in FIG. 2B, the joint portion between the inner wall of the insertion hole 15a and the lower end portion of the cell 1 is filled with a fixing material 13 and solidified. Thereby, the inner wall of the insertion hole 15a and the lower end portions of the plurality of cells 1 are joined and fixed respectively, and the lower end portions of the cells 1 are joined and fixed to each other. The gas flow path 2a of each cell 1 communicates with the internal space 22 of the support member 14 at the lower end portion.

[0050] As the fixing material 13 and the joining material 21, those with low conductivity such as glass can be used. As specific materials for the fixing material 13 and the joining material 21, amorphous glass or the like may be used, and particularly, crystallized glass or the like may be used.

[0051] As the crystallized glass, for example, any of materials such as SiO2-CaO system, MgO-B2O3 system, La2O3-B2O3-MgO system, La2O3-B2O3-ZnO system, SiO2-CaO-ZnO system may be used, and particularly, a material of SiO2-MgO system may be used.

[0052] Further, as shown in FIG. 2B, a conductive member 18 is interposed between adjacent cells 1 among the plurality of cells 1. The conductive member 18 electrically connects one adjacent cell 1 and the other cell 1 in series. More specifically, the conductive member 18 connects the fuel electrode 5 of one cell 1 and the air electrode 8 of the other cell 1.

[0053] Further, as shown in FIG. 2B, an end collector member 17 is electrically connected to the outermost cell 1 in the arrangement direction of the plurality of cells 1. The end collector member 17 is connected to a conductive portion 19 that protrudes outside the cell stack 11. The conductive portion 19 collects the electricity generated by the power generation of the cell 1 and draws it out to the outside. In FIG. 2A, the illustration of the end collector member 17 is omitted.

[0054] Further, as shown in FIG. 2C, the cell stack device 10 may be a single battery in which two cell stacks 11A and 11B are connected in series. In such a case, the conductive portion 19 of the cell stack device 10 may have a positive terminal 19A, a negative terminal 19B, and a connection terminal 19C.

[0055] The positive terminal 19A is the positive electrode when the cell stack 11 outputs the generated power to the outside, and is electrically connected to the end collector member 17 on the positive electrode side in the cell stack 11A. The negative terminal 19B is the negative electrode when the cell stack 11 outputs the generated power to the outside, and is electrically connected to the end collector member 17 on the negative electrode side in the cell stack 11B.

[0056] The connection terminal 19C electrically connects the end collector member 17 on the negative electrode side in the cell stack 11A and the end collector member 17 on the positive electrode side in the cell stack 11B.

[0057] <Joining of Metal Member and Sealing Material> Next, the joining of the interconnector 4 and the sealing material 25 will be described with reference to FIGS. 3A to 3Y. FIGS. 3A to 3J are enlarged cross-sectional views of the region A shown in FIG. 1A, and FIGS. 3K to 3Y are enlarged cross-sectional views of the region B shown in FIG. 1D.

[0058] As shown in FIG. 3A, the sealing material 25 is joined to the interconnector 4 via the intermediate material 24.

[0059] The intermediate material 24 has surfaces 241 and 242 that contact the sealing material 25 and surfaces 243 and 244 that contact the interconnector 4. The intermediate material 24 also has a surface 245 that is exposed to the external space 23. Surfaces 242 and 244 are positioned along the width direction W shown in FIG. 1A, and surfaces 241 and 243 are positioned along the thickness direction T shown in FIG. 1A. The external space 23 is a space where the air electrode 8 (see FIG. 1A) of the cell 1 is exposed and is filled with an oxygen-containing gas such as air. That is, the external space 23 is an oxidizing atmosphere.

[0060] As described above, the interconnector 4 contains chromium. For example, if the chromium contained in the interconnector 4 desorbs into the oxidizing atmosphere (external space 23), the durability of the interconnector 4 may decrease.

[0061] Therefore, in the present embodiment, the surface roughness of the intermediate material 24 located near the oxidizing atmosphere (external space 23) can be made smaller than the surface roughness of the intermediate material 24 closer to the support substrate 2, which is in a reducing atmosphere, that is, farther from the oxidizing atmosphere (external space 23). In the embodiment, the surface roughness of surface 245 is smaller than the surface roughness of surface 241.

[0062] Thereby, for example, even during high-temperature operation, the chromium contained in the interconnector 4 can be made less likely to desorb into the oxidizing atmosphere (external space 23). That is, by reducing the surface roughness of the surface 245 of the intermediate material 24, which is close to the oxidizing atmosphere and makes it difficult for chromium to desorb into the oxidizing atmosphere, it is possible to further make it difficult for chromium to desorb into the oxidizing atmosphere. Therefore, according to the present embodiment, since the durability of the cell 1 can be enhanced, the durability of the cell stack device 10 can be enhanced.

[0063] The surface roughness of the surface 245 located near the oxidizing atmosphere may be smaller than, for example, the normal surface roughness of 8 μm to 30 μm of insulating oxides such as forsterite provided on a metal surface. The surface roughness of the surface 241 may be the same as or larger than the normal surface roughness of such insulating oxides.

[0064] In addition, the surface roughness of the surface 242 located between the surface 241 and the surface 245 may be the same as the surface roughness of the surface 241 or the same as the surface roughness of the surface 245. Further, the surface 242 may have a surface roughness intermediate between the surface 241 and the surface 245.

[0065] The sealing material 25 is joined to the intermediate member 24. Depending on the operating environment, fuel gas may leak from a gap generated by the peeling of the sealing material 25 from the intermediate member 24, which may reduce the durability of the cell stack device 10.

[0066] Therefore, the surface roughness of the surface 242 can be made larger than the surface roughness of the surface 241. Thereby, for example, the adhesion between the surface 242 of the intermediate member 24 and the sealing material 25 can be enhanced. For this reason, for example, it becomes difficult for the sealing material 25 to peel from the side of the surface 242 close to the surface 245 exposed to the oxidizing atmosphere (external space 23), and it is possible to make it difficult for fuel gas to leak. Therefore, according to the present embodiment, the durability of the cell stack device 10 can be enhanced. Further, the sealing material 25 is also in contact with the surface 241. When the surface roughness of the surface 241 is large, the adhesion between the surface 241 and the sealing material 25 can be enhanced. The surface roughness of the surface 242 and the surface 245 may be larger than the normal surface roughness of the above-described insulating oxide.

[0067] As shown in FIGS. 3B to 3F, the sealing material 25 or the adhesive material 9 may be located between the intermediate member 24 and the solid electrolyte layer 6, between the respective components of the cell 1, etc. Further, as shown in FIGS. 3G to 3J, a gap S may exist between the sealing material 25 and the respective components of the cell 1. Even in such a case, the durability of the cell stack device 10 can be enhanced as shown in FIG. 3A.

[0068] Further, as shown in FIGS. 3K, 3L to 3S, a sealing material 25 or an adhesive 9 may be located between the intermediate member 24 and the solid electrolyte layer 6, or between each component member of the cell 1. Further, as shown in FIGS. 3T to 3Y, a gap S may exist between the sealing material 25 and each component member of the cell 1. Even in such a case, the durability of the cell stack device 10 can be enhanced as shown in FIG. 3A.

[0069] In the above-described embodiment, the durability of the cell 1 is enhanced by having portions with different surface roughnesses at different positions of the intermediate member 24. However, the durability of the cell 1 can also be enhanced by having portions with different thicknesses at different positions of the intermediate member 24.

[0070] FIG. 4 is a cross-sectional view showing another example of the electrochemical cell according to the first embodiment. As shown in FIG. 4, the intermediate member 24 may have a first portion P1 and a second portion P2. The first portion P1 is located between the surface 241 and the surface 243, and the second portion P2 is located between the surface 242 and the surface 244. The second portion P2 is a portion closer to the oxidizing atmosphere (external space 23). The first portion P1 is farther from the oxidizing atmosphere (external space 23) than the second portion P2 and is a portion closer to the support substrate 2 in a reducing atmosphere.

[0071] As shown in FIG. 4, the intermediate member 24 may have a thickness t2, which is the average thickness of the second portion P2, larger than the thickness t1, which is the average thickness of the first portion P1. Thereby, for example, even during high-temperature operation, chromium contained in the interconnector 4 can be made less likely to desorb into the oxidizing atmosphere (external space 23). Therefore, according to this configuration, since the durability of the cell 1 can be enhanced, the durability of the cell stack device 10 can be enhanced. The second portion P2 of the intermediate member 24 may have a thickness t1 of, for example, 30 μm or more.

[0072] FIG. 5 is a cross-sectional view showing another example of the electrochemical cell according to the first embodiment. The intermediate member 24 may enhance the durability of the cell 1 by having different surface roughnesses at the first interface 24a facing the sealing member 25 and the second interface 24b facing the interconnector 4.

[0073] Specifically, the surface roughness of the first interface 24a may be greater than the surface roughness of the second interface 24b. Thereby, the adhesion between the intermediate member 24 and the sealing member 25 can be enhanced. For this reason, it becomes difficult for the sealing member 25 to peel off from the intermediate member 24, and it is possible to hardly cause a leak of the fuel gas. Therefore, according to this configuration, since the durability of the cell 1 can be enhanced, the durability of the fuel cell stack device 10 can be enhanced.

[0074] As shown in FIG. 5, the first interface 24a includes interfaces 24a1 and 24a2, and the second interface 24b includes interfaces 24b1 and 24b2. The surface roughness of the first interface 24a can be, for example, the average value of the surface roughnesses of the interfaces 24a1 and 24a2. The surface roughness of the second interface 24b can be, for example, the average value of the surface roughnesses of the interfaces 24b1 and 24b2.

[0075] The sealing member 25 is considered to be more likely to peel off from the interface 24a2 side of the intermediate member 24 as compared with the interface 24a1. The surface roughness of the interface 24a2 may be greater than the surface roughness of the interface 24b2. Thereby, the sealing member 25 becomes difficult to peel off from the interface 24a2 side, and it is possible to hardly cause a leak of the fuel gas. Therefore, since the durability of the cell 1 can be enhanced, the durability of the fuel cell stack device 10 can be enhanced.

[0076] FIG. 6 is a cross-sectional view showing another example of the electrochemical cell according to the first embodiment. By adjusting the content rate of a specific metal element located at the boundary between the interconnector 4 and the intermediate member 24 to be different from the content rate of the metal element in the interconnector 4 or the intermediate member 24, the durability of the cell 1 may be enhanced. The boundary between the interconnector 4 and the intermediate member 24 is a part of the interconnector 4 and a part of the intermediate member 24 located near the interface between the interconnector 4 and the intermediate member 24, and includes the interface between the interconnector 4 and the intermediate member 24.

[0077] Specifically, at least one element among Mn, Ti, Ca, and Al may be located near the interface 24i which is the boundary between the interconnector 4 and the intermediate member 24. Also, the first content rate which is the total content rate of Mn, Ti, Ca, and Al near the interface 24i may be larger than the second content rate which is the total content rate of Mn, Ti, Ca, and Al inside the interconnector 4 or inside the intermediate member 24. Note that the inside of the interconnector 4 may be a part of the interconnector 4 sufficiently separated from the interface 24i, for example, a part located equidistant from the intermediate member 24 and the adhesive 9 or a part closer to the adhesive 9 than that. The inside of the intermediate member 24 may be a part of the intermediate member 24 sufficiently separated from the interface 24i, for example, a part located equidistant from the interconnector 4 and the sealant 25 or a part closer to the sealant 25 than that. Also, the vicinity of the interface 24i may be, for example, a region where the distance from the interface 24i is 300 nm or less.

[0078] Thereby, the adhesion between the interconnector 4 and the intermediate member 24 can be enhanced. For this reason, it becomes difficult for the interconnector 4 and the intermediate member 24 to peel off, and it becomes difficult for fuel gas to leak. Therefore, since the durability of the cell 1 can be enhanced, the durability of the fuel cell stack device 10 can be enhanced.

[0079] The above-described specific element located near the interface 24i can be located as a single substance, an alloy, or a metal oxide. Further, such an element may be located on either the interconnector 4 side or the intermediate member 24 side, or may be located so as to straddle the interconnector 4 and the intermediate member 24. Further, such an element may be located over the entire interface 24i, or may be located only on one of, for example, the interface 24i1 or the interface 24i2.

[0080] <Module> Next, a module according to an embodiment of the present disclosure using the above-described cell stack device 10 will be described with reference to FIG. 7. FIG. 7 is an external perspective view showing a module according to the first embodiment. FIG. 7 shows a state in which a front surface and a rear surface, which are parts of the storage container 101, are removed, and the cell stack device 10 of the fuel cell stored inside is taken out backward.

[0081] As shown in FIG. 7, the module 100 includes a storage container 101 and a cell stack device 10 stored in the storage container 101. Further, a reformer 102 is disposed above the cell stack device 10.

[0082] Such a reformer 102 reforms a raw fuel such as natural gas or kerosene to generate a fuel gas and supplies it to the cell 1. The raw fuel is supplied to the reformer 102 through the raw fuel supply pipe 103. The reformer 102 may include a vaporization unit 102a that vaporizes water and a reforming unit 102b. The reforming unit 102b includes a reforming catalyst (not shown) and reforms the raw fuel into a fuel gas. Such a reformer 102 can perform steam reforming, which is an efficient reforming reaction.

[0083] Then, the fuel gas generated by the reformer 102 is supplied to the gas flow path 2a (see FIG. 1A) of the cell 1 through the gas flow pipe 20, the gas tank 16, and the support member 14.

[0084] In addition, in the module 100 with the above-described configuration, the temperature inside the module 100 during normal power generation becomes about 500°C to 1000°C due to the combustion of gas and the power generation of the cell 1.

[0085] In such a module 100, as described above, by incorporating the highly durable cell stack device 10, a highly durable module 100 can be achieved.

[0086] <Module housing device> FIG. 8 is an exploded perspective view showing an example of a module housing device according to the first embodiment. The module housing device 110 according to this embodiment includes an exterior case 111, the module 100 shown in FIG. 7, and auxiliary equipment (not shown). The auxiliary equipment operates the module 100. The module 100 and the auxiliary equipment are housed inside the exterior case 111. Note that a part of the configuration is omitted in FIG. 8.

[0087] The exterior case 111 of the module housing device 110 shown in FIG. 8 has support columns 112 and an exterior plate 113. A partition plate 114 vertically divides the inside of the exterior case 111. The space above the partition plate 114 inside the exterior case 111 is a module housing chamber 115 for housing the module 100, and the space below the partition plate 114 inside the exterior case 111 is an auxiliary equipment housing chamber 116 for housing the auxiliary equipment that operates the module 100. Note that in FIG. 8, the auxiliary equipment housed in the auxiliary equipment housing chamber 116 is omitted.

[0088] In addition, the partition plate 114 has an air circulation port 117 for flowing the air in the auxiliary equipment housing chamber 116 to the module housing chamber 115 side. The exterior plate 113 constituting the module housing chamber 115 has an exhaust port 118 for exhausting the air inside the module housing chamber 115.

[0089] In such a module housing device 110, as described above, by providing the highly durable module 100 in the module housing chamber 115, a highly durable module housing device 110 can be achieved.

[0090] [Second Embodiment] FIG. 9 is a cross-sectional view showing an example of an electrochemical cell according to the second embodiment. The cell 1A includes an element portion 3, a support substrate 2, an adhesive 9, an interconnector 4, a sealing material 25, and an intermediate member 44.

[0091] The support substrate 2 is a flat metal plate having one surface and the other surface facing it. The support substrate 2 has a gas flow path 2a on one surface side. The element portion 3 is located on the other surface side of the support substrate 2. The support substrate 2 has through holes or pores at a portion in contact with the element portion 3, and can allow gas to flow between the gas flow path 2a and the element portion 3. The material of the metal plate may be the same as or similar to the material of the interconnector 4 containing chromium. In the present embodiment, the support substrate 2 is an example of a metal member.

[0092] The interconnector 4 is provided on one surface side of the support substrate 2 where the gas flow path 2a is located.

[0093] The sealing material 25 is located at the end faces of the element portion 3 and the adhesive 9. The sealing material 25 fixes the element portion 3 and the support substrate 2 and makes it difficult for fuel gas to leak. The sealing material 25 may be located away from the air electrode 8.

[0094] The intermediate member 44 is located between the support substrate 2 and the sealing material 25. Since the intermediate member 44 enhances the adhesion between the sealing material 25 and the support substrate 2, the durability of the cell 1A can be enhanced. The material of the intermediate member 44 may be the same as the material of the intermediate member 24 according to the above-described embodiment.

[0095] [Joining of Metal Member and Sealing Material] FIG. 10 is an enlarged cross-sectional view of the region C shown in FIG. 9. As shown in FIG. 10, the sealing material 25 is joined to the support substrate 2 via the intermediate member 44.

[0096] The intermediate member 44 has a surface 441 that contacts the sealing member 25, a surface 442 that contacts the support substrate 2, and a surface 443 that contacts the adhesive 9. Further, the intermediate member 44 has a surface 444 located on the external space 23 side.

[0097] As described above, the support substrate 2 contains chromium. For example, if the chromium contained in the support substrate 2 desorbs into the oxidizing atmosphere (external space 23), the durability of the support substrate 2 may decrease.

[0098] Therefore, in the present embodiment, the surface roughness of the intermediate member 44 located near the oxidizing atmosphere (external space 23) can be made smaller than the surface roughness of the intermediate member 44 closer to the fuel electrode 5 or the adhesive 9, which is in a reducing atmosphere, i.e., farther from the oxidizing atmosphere (external space 23). In the embodiment, the surface roughness of the surface 444 is smaller than the surface roughness of the surface 443.

[0099] Thereby, for example, even during high-temperature operation, it is possible to make it difficult for the chromium contained in the support substrate 2 to desorb into the oxidizing atmosphere (external space 23). Therefore, according to the present embodiment, since the durability of the cell 1A can be enhanced, the durability of the fuel cell stack device 10 can be enhanced.

[0100] Note that the surface roughness of the surface 441 located between the surface 444 and the surface 443 may be the same as the surface roughness of the surface 444 or may be the same as the surface roughness of the surface 443. Further, the surface 441 may have a surface roughness intermediate between the surface 444 and the surface 443.

[0101] The sealing member 25 is joined to the intermediate member 44, and depending on the operating environment, fuel gas may leak from a gap generated by peeling of the sealing member 25 from the intermediate member 44, which may reduce the durability of the fuel cell stack device 10.

[0102] Therefore, the surface roughness of surface 441 can be made greater than that of surface 444. Thereby, for example, the adhesion between surface 441 of intermediate member 44 and sealing material 25 can be enhanced. For this reason, for example, the sealing material 25 is less likely to peel from surface 441 located on the side of surface 444 that is exposed to the oxidizing atmosphere (external space 23), and it is possible to make it less likely for fuel gas to leak. Therefore, according to the present embodiment, the durability of the cell stack device 10 can be enhanced.

[0103] In the above-described embodiment, the durability of cell 1A is enhanced by having portions with different surface roughnesses at different positions of intermediate member 44. However, the durability of cell 1A can also be enhanced by having portions with different thicknesses at different positions of intermediate member 44.

[0104] FIG. 11 is a cross-sectional view showing another example of the electrochemical cell according to the second embodiment. The intermediate member 44 shown in FIG. 11 has a surface 443 as a first portion and a surface 444 as a second portion. Surface 444 is a portion close to the oxidizing atmosphere (external space 23). Surface 443 is farther from the oxidizing atmosphere (external space 23) than surface 444 and is a portion close to the reducing atmosphere. Fuel electrode 5 or adhesive 9 is a portion close to

[0105] As shown in FIG. 11, for the intermediate member 44, the thickness t22, which is the average thickness of surface 444, may be greater than the thickness t21, which is the average thickness of surface 443. Thereby, for example, even during high-temperature operation, it is possible to make it difficult for the chromium contained in the support substrate 2 to desorb into the oxidizing atmosphere (external space 23). Therefore, according to this configuration, since the durability of cell 1A can be enhanced, the durability of the cell stack device 10 can be enhanced.

[0106] FIG. 12 is a cross-sectional view showing another example of the electrochemical cell according to the second embodiment. The durability of cell 1A may be enhanced by having different surface roughnesses at the first interface 44a of intermediate member 44 facing the sealing material 25 and the second interface 44b of intermediate member 44 facing the support substrate 2.

[0107] Specifically, the surface roughness of the first interface 44a may be greater than the surface roughness of the second interface 44b. Thereby, the adhesion between the intermediate member 44 and the sealing member 25 can be enhanced. For this reason, it becomes difficult for the sealing member 25 to peel from the intermediate member 44, and it is possible to make it difficult for fuel gas to leak. Therefore, according to this configuration, since the durability of the cell 1A can be enhanced, the durability of the fuel cell stack device 10 can be enhanced.

[0108] FIG. 13 is a cross-sectional view showing another example of the electrochemical cell according to the second embodiment. By adjusting the content ratio of a specific metal element located at the boundary between the support substrate 2 and the intermediate member 44 to be different from the content ratio of the metal element in the support substrate 2 or the intermediate member 44, the cell 1 A may have enhanced durability.

[0109] Specifically, at least one element among Mn, Ti, Ca, and Al is located in the vicinity of the interface 44i, which is the boundary between the support substrate 2 and the intermediate member 44. Further, the first content ratio, which is the total content ratio of Mn, Ti, Ca, and Al in the vicinity of the interface 44i, may be greater than the second content ratio, which is the total content ratio of Mn, Ti, Ca, and Al inside the support substrate 2 or inside the intermediate member 44.

[0110] Thereby, the adhesion between the support substrate 2 and the intermediate member 44 can be enhanced. For this reason, it becomes difficult for the support substrate 2 and the intermediate member 44 to peel from each other, and it becomes difficult for fuel gas to leak. Therefore, since the durability of the cell 1A can be enhanced, the durability of the fuel cell stack device 10 can be enhanced.

[0111] Note that the above-described specific element located in the vicinity of the interface 44i can be located as a single substance, an alloy, or a metal oxide. Further, such an element may be located on either the support substrate 2 side or the intermediate member 44 side, or may be located so as to straddle the support substrate 2 and the intermediate member 44. Further, such an element may be located over the entire interface 44i, or may be located only in a part of the interface 44i, for example.

[0112] <Evaluation method> Here, the thicknesses of the respective parts of the above-described intermediate materials 24 and 44 are calculated by image analysis of a cross-section perpendicular to the surface of each part. First, the intermediate materials 24 and 44, the interconnector 4, the support substrate 2, and the sealing material 25 are cut out, embedded in resin, and a cross-section perpendicular to the surface of each part is polished using abrasive grains, a lapping film (about #8000), etc. to obtain a mirror-like cross-section. The obtained cross-section is photographed using an SEM (scanning electron microscope), an optical microscope, etc., and the thicknesses of the respective parts can be measured by image analysis of the obtained image. Note that the thickness of each part of the intermediate materials 24 and 44 can be, for example, the average value of the thicknesses measured at three arbitrary locations of each part.

[0113] Also, the magnitudes of the surface roughnesses of the respective surfaces of the above-described intermediate materials 24 and 44 can be determined based on the arithmetic mean roughness Ra defined in JIS B0633;2001. The arithmetic mean roughness Ra can be calculated by image analysis of a cross-section perpendicular to the surface for measuring the surface roughness, as in the case of measuring the thickness of each part. Note that the surface roughness of each surface of the intermediate materials 24 and 44 can be, for example, the average value of the surface roughnesses measured at three arbitrary locations of each surface.

[0114] In addition, the contents of Mn, Ti, Ca, and Al in each part of the intermediate materials 24 and 44, the interconnector 4, the support substrate 2, and the sealing material 25 can be confirmed, for example, by cutting or scraping each part from cells 1 and 1A and performing elemental analysis such as ICP emission spectrometry. Whether specific elements are present at the boundary of each member can be determined by using a scanning electron microscope (SEM), a transmission electron microscope (TEM), a scanning transmission electron microscope (STEM), etc., and an electron probe microanalyzer (EPMA), wavelength-dispersive X-ray spectroscopy (WDS), or energy-dispersive X-ray spectroscopy (EDS), etc., for elemental analysis of a cross-section including the boundary, such as specific element mapping. Further, the contents of Mn, Ti, Ca, and Al in each member and at the boundary of each member can be calculated by performing elemental analysis on the cross-sections of the intermediate materials 24 and 44, the interconnector 4, the support substrate 2, and the sealing material 25 using an electron probe microanalyzer (EPMA), wavelength-dispersive X-ray spectroscopy (WDS), or energy-dispersive X-ray spectroscopy (EDS), etc.

[0115] (Thickness of intermediate material) As calculated above, the thickness of the intermediate materials 24 and 44 can be, for example, 2 μm to 400 μm on average for the entire intermediate materials 24 and 44.

[0116] (Surface roughness of each surface) As calculated above, the surface roughness (arithmetic mean roughness Ra) of each surface of the intermediate materials 24 and 44 may be, for example, 0.1 μm to 30 μm. Among the surfaces of the intermediate materials 24 and 44, the surface roughness (arithmetic mean roughness Ra) of some surfaces may be, for example, 0.1 μm to 30 μm.

[0117] (Contents of Mn, Ti, Ca, and Al) The content ratios of Mn, Ti, Ca, and Al in each part of the intermediate materials 24 and 44, the interconnector 4, the support substrate 2, and the sealing material 25 calculated as described above can be, for example, 0.01% by mass to 10% by mass. Further, the content ratios of Mn, Ti, Ca, and Al in the intermediate materials 24 and 44, the interconnector 4, the support substrate 2, and the boundary parts between the intermediate materials 24 and 44 and the interconnector 4 and the support substrate 2 can be, for example, 0.01% by mass to 10% by mass (for the intermediate materials 24 and 44), 0.01% by mass to 10% by mass (for the interconnector 4 and the support substrate 2), and 0.1% by mass to 30% by mass (for the boundary parts), respectively.

[0118] (Manufacturing method) The intermediate materials 24 and 44 according to the embodiment can be positioned by methods such as a spraying method, a vapor deposition method, an electrodeposition method, and a sputtering method. Further, for example, a coating material may be applied to the surface of the interconnector 4 or the support substrate 2 and then fired to form the intermediate materials 24 and 44.

[0119] Further, the surface roughness of each surface of the intermediate materials 24 and 44 and / or the thickness of each part of the intermediate materials 24 and 44 may be polished, for example, to have desired values. Further, desired values may be obtained by changing various conditions during the formation of the intermediate materials 24 and 44 described above. Further, for other surfaces, they can be formed by appropriately combining the manufacturing methods of the intermediate materials 24 and 44 described above and known techniques.

[0120] [Other embodiments] In the above-described embodiments, a fuel cell, a fuel cell stack device, a fuel cell module, and a fuel cell device are shown as examples of an "electrochemical cell", an "electrochemical cell device", a "module", and a "module housing device". However, as other examples, an electrolytic cell, an electrolytic cell stack device, an electrolytic module, and an electrolytic device may be used, respectively. The electrolytic cell has a first electrode and a second electrode, and decomposes water vapor into hydrogen and oxygen or decomposes carbon dioxide into carbon monoxide and oxygen by supplying power. Further, in the above-described embodiments, an oxide ion conductor or a hydrogen ion conductor is shown as an example of the electrolyte material of the electrochemical cell, but a hydroxide ion conductor may also be used. Even in such an electrolytic cell, an electrolytic cell stack device, an electrolytic module, and an electrolytic device, the durability can be enhanced.

[0121] As described above in detail, the present disclosure is not limited to the above-described embodiments, and various changes, improvements, etc. are possible without departing from the gist of the present disclosure.

[0122] As described above, the electrochemical cell according to the embodiment (for example, cell 1) includes a porous part (for example, support substrate 2), a metal member (for example, interconnector 4), a sealing material (for example, sealing material 25), and an intermediate material (for example, intermediate material 24). The porous part has conductivity. The metal member contains chromium. The sealing material is located on the porous part and the metal member. The intermediate material is located between the metal member and the sealing material. The intermediate material has two or more portions with different surface roughnesses or thicknesses at different positions. Thereby, the durability of the electrochemical cell can be enhanced.

[0123] Further, the electrochemical cell according to the embodiment (for example, cell 1) includes a porous portion (for example, support substrate 2), a metal member (for example, interconnect 4), a sealing material (for example, sealing material 25), and an intermediate member (for example, intermediate member 24). The porous portion has conductivity. The metal member contains chromium. The sealing material is located on the porous portion and the metal member. The intermediate member is located between the metal member and the sealing material. The surface roughness of the first interface of the intermediate member facing the sealing material is different from the surface roughness of the second interface of the intermediate member facing the metal member. Thereby, the durability of the electrochemical cell can be enhanced.

[0124] Further, the electrochemical cell according to the embodiment (for example, cell 1) includes a porous portion (for example, support substrate 2), a metal member (for example, interconnect 4), a sealing material (for example, sealing material 25), and an intermediate member (for example, intermediate member 24). The porous portion has conductivity. The metal member contains chromium. The sealing material is located on the porous portion and the metal member. The intermediate member is located between the metal member and the sealing material. At least one element of Mn, Ti, Ca, and Al is located at the boundary between the metal member and the intermediate member. A first content rate, which is the total content rate of Mn, Ti, Ca, and Al at the boundary, is different from a second content rate, which is the total content rate of Mn, Ti, Ca, and Al inside the metal member or inside the intermediate member. Thereby, the durability of the electrochemical cell can be enhanced.

[0125] Further, the electrochemical cell device of the present disclosure (for example, cell stack device 10) has a cell stack including the electrochemical cell described above. Thereby, an electrochemical cell device with high durability can be obtained.

[0126] Further, the module 100 of the present disclosure includes the electrochemical cell device described above and a storage container 101 for storing the electrochemical cell device. Thereby, a module 100 with high durability can be obtained.

[0127] In addition, the module housing device 110 of the present disclosure includes the module 100 described above, auxiliary equipment for operating the module 100, and an exterior case for housing the module 100 and the auxiliary equipment. Thereby, a highly durable module housing device 110 can be obtained.

[0128] It should be considered that all aspects of the embodiments disclosed this time are illustrative and not restrictive. Indeed, the above-described embodiments can be embodied in various forms. Also, the above embodiments may be omitted, replaced, or changed in various forms without departing from the scope and spirit of the appended claims.

Explanation of Reference Numerals

[0129] 1, 1A cells 4 interconnect 10-cell stack device 11-cell stack 12 fixing member 13 fixing material 14 supporting member 15 support 16 gas tank 17 end current collecting member 18 conductive member 23 external space 24, 44 intermediate material 25 sealing material 100 module 110 module housing device

Claims

1. A porous part having conductivity, A metal member containing chromium, A sealing material located on the porous part and the metal member, An intermediate material located between the metal member and the sealing material and comprising, The intermediate material has two or more parts with different surface roughnesses or thicknesses at different positions An electrochemical cell.

2. The intermediate material is an insulating oxide The electrochemical cell according to claim 1.

3. The intermediate material has a first surface closer to a reducing atmosphere and a second surface closer to an oxidizing atmosphere than the first surface, The surface roughness of the second surface is smaller than the surface roughness of the first surface The electrochemical cell according to claim 1.

4. The intermediate material has a first part closer to a reducing atmosphere and a second part closer to an oxidizing atmosphere than the first part, The thickness of the second part is larger than the thickness of the first part The electrochemical cell according to claim 1.

5. A porous part having conductivity, A metal member containing chromium, A sealing material located on the porous part and the metal member, An intermediate material located between the metal member and the sealing material and comprising, The surface roughness of the first interface of the intermediate material facing the sealing material is different from the surface roughness of the second interface of the intermediate material facing the metal member An electrochemical cell.

6. The surface roughness of the first interface is larger than the surface roughness of the second interface The electrochemical cell according to claim 5.

7. A porous part having conductivity, A metal member containing chromium, A sealing material located on the porous part and the metal member, An intermediate material located between the metal member and the sealing material and comprising, At least one element of Mn, Ti, Ca, and Al is located at the boundary between the metal member and the intermediate material, and a first content rate that is the total content rate of Mn, Ti, Ca, and Al at the boundary is different from a second content rate that is the total content rate of Mn, Ti, Ca, and Al inside the metal member or inside the intermediate material An electrochemical cell.

8. The first content rate is larger than the second content rate The electrochemical cell according to claim 7.

9. Having a cell stack comprising the electrochemical cell according to any one of claims 1 to 8 An electrochemical cell device.

10. The electrochemical cell device according to claim 9, A storage container for storing the electrochemical cell device and comprising.

11. The module according to claim 10, Auxiliary equipment for operating the module, An exterior case that houses the module and the auxiliary machine, and A module housing device comprising the same.

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