Metal member with coating layer

Abstract

To provide a metal member with a coating layer that has high durability.SOLUTION: A metal member with a coating layer comprises a metal member and a coating layer. The metal member contains chromium. The coating layer covers the metal member. The coating layer has a second outer face exposed to an oxidative atmosphere and a first outer face located separated from the oxidative atmosphere. The thickness of the coating layer where the second outer face is located is larger than the thickness of the coating layer where the first outer face is located, or the surface roughness of the second outer face is smaller than the surface roughness of the first outer face.SELECTED DRAWING: Figure 3B

Description

[Technical Field]

[0001] The present disclosure relates to a metal member with a coating layer. [Background technology]

[0002] In recent years, various fuel cell stack devices having multiple fuel cell units have been proposed as next-generation energy sources. A fuel cell unit is a type of cell that can generate electricity 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] Japanese Patent Application Laid-Open No. 2015-162357 Summary of the Invention

[0004] A metal member with a coating layer according to one aspect of the embodiment includes a metal member and a coating layer. The metal member contains chromium. The coating layer covers the metal member. The coating layer has a second outer surface exposed to an oxidizing atmosphere and a first outer surface located away from the oxidizing atmosphere. The thickness of the coating layer where the second outer surface is located is greater than the thickness of the coating layer where the first outer surface is located, or the surface roughness of the second outer surface is smaller than the surface roughness of the first outer surface. [Brief explanation of the drawings]

[0005] [Figure 1A] FIG. 1A is a cross-sectional view showing an example of a cell according to an embodiment. [Figure 1B] FIG. 1B is a side view of an example of a cell according to an embodiment, viewed from the air electrode side. [Figure 1C] FIG. 1C is a side view of an example of a cell according to an embodiment, viewed from the interconnector side. [Figure 2A] FIG. 2A is a perspective view showing an example of a cell stack device according to an embodiment. [Figure 2B]FIG. 2B is a cross-sectional view taken along line XX shown in FIG. 2A. [Figure 2C] FIG. 2C is a top view showing an example of a cell stack device according to an embodiment. [Figure 3A] FIG. 3A is a cross-sectional view taken along line YY shown in FIG. 2C. [Figure 3B] FIG. 3B is an enlarged cross-sectional view that schematically shows a main part of the cell stack shown in FIG. 3A. [Figure 4] FIG. 4 is a cross-sectional view taken along line ZZ shown in FIG. 2C. [Figure 5A] FIG. 5A is a perspective view showing another example of the metal member. [Figure 5B] FIG. 5B is a perspective view showing another example of the metal member. [Figure 5C] FIG. 5C is an enlarged cross-sectional view of a joint between another example of the metal member and the cell. [Figure 6A] FIG. 6A is an enlarged cross-sectional view of a joint between a metal member and a cell according to Modification 1 of the embodiment. [Figure 6B] FIG. 6B is an enlarged cross-sectional view of a joint between a metal member and a cell according to the second modification of the embodiment. [Figure 6C] FIG. 6C is an enlarged cross-sectional view of a joint between a metal member and a cell according to the third modification of the embodiment. [Figure 6D] FIG. 6D is a cross-sectional view showing a metal member according to a fourth modification of the embodiment. [Figure 6E] FIG. 6E is a cross-sectional view showing a metal member according to a fifth modification of the embodiment. [Figure 7A] FIG. 7A is an enlarged cross-sectional view of a joint between another example of a metal member according to the sixth modification of the embodiment and a cell. [Figure 7B] FIG. 7B is an enlarged cross-sectional view of a joint between another example of a metal member according to the seventh modification of the embodiment and a cell. [Figure 8A] FIG. 8A is a front view showing an end current collecting member according to Modification 8 of the embodiment. [Figure 8B] FIG. 8B is a cross-sectional view showing an end current collecting member according to Modification 9 of the embodiment. [Figure 8C]FIG. 8C is an enlarged cross-sectional view of a joint between an end current collecting member and a metal member according to the tenth modification of the embodiment. [Figure 8D] FIG. 8D is an enlarged cross-sectional view of a joint between an end current collecting member and a metal member according to Modification 11 of the embodiment. [Figure 9] FIG. 9 is an external perspective view showing an example of a module according to the embodiment. [Figure 10] FIG. 10 is an exploded perspective view schematically illustrating an example of a module housing device according to an embodiment. [Figure 11A] FIG. 11A is a perspective view showing a flat cell according to a twelfth modification of the embodiment. [Figure 11B] FIG. 11B is a partial cross-sectional view of the flat cell shown in FIG. 11A. [Figure 11C] FIG. 11C is an enlarged view of area A shown in FIG. 11B. DETAILED DESCRIPTION OF THE INVENTION

[0006] Hereinafter, embodiments of the metal member with a coating layer disclosed in the present application will be described in detail with reference to the accompanying drawings. However, the present disclosure is not limited to the embodiments described below.

[0007] It should also be noted that the drawings are schematic and that the dimensional relationships and ratios of elements may differ from reality. Furthermore, the drawings may contain parts whose dimensional relationships and ratios differ from one another.

[0008] <Cell configuration> First, with reference to FIGS. 1A to 1C, a description will be given using an example of a solid oxide fuel cell as a cell constituting a cell stack device according to an embodiment.

[0009] Fig. 1A is a cross-sectional view showing an example of a cell 1 according to an embodiment, Fig. 1B is a side view of the example of the cell 1 according to an embodiment as seen from the air electrode 5 side, and Fig. 1C is a side view of the example of the cell 1 according to an embodiment as seen from the interconnector 6 side. Figs. 1A to 1C show enlarged views of parts of each component of the cell 1.

[0010] 1A to 1C, cell 1 is a hollow, flat, elongated plate. As shown in Fig. 1B, the shape of the entire cell 1 as viewed from the side is, for example, a rectangle with sides measuring 5 cm to 50 cm in the length direction L and 1 cm to 10 cm in the width direction W perpendicular to the length direction L. The thickness of the entire cell 1 in the thickness direction T is, for example, 1 mm to 5 mm.

[0011] 1A, the cell 1 includes a conductive support substrate 2, an element section, and an interconnector 6. The support substrate 2 is columnar, having a pair of opposing flat surfaces n1, n2 and a pair of arc-shaped side surfaces m connecting the flat surfaces n1, n2.

[0012] The element portion is provided on a flat surface n1 of a support substrate 2. The element portion has a fuel electrode 3, a solid electrolyte layer 4, and an air electrode 5. In the example shown in FIG. 1A, an interconnector 6 is provided on the flat surface n2 of the cell 1.

[0013] As shown in FIG. 1B, the air electrode 5 does not extend to the upper and lower ends of the cell 1. At the lower end of the cell 1, only the solid electrolyte layer 4 is exposed on the surface. As shown in FIG. 1C, the interconnector 6 may extend to the upper and lower ends of the cell 1. At the lower end of the cell 1, the interconnector 6 and the solid electrolyte layer 4 are exposed on the surface. As shown in FIG. 1A, the solid electrolyte layer 4 is exposed on the surface of a pair of arc-shaped side surfaces m of the cell 1. The interconnector 6 does not have to extend to the lower end of the cell 1.

[0014] Each of the components that make up the cell 1 will be described below.

[0015] The support substrate 2 has gas flow channels 2a therein through which gas flows. The example of the support substrate 2 shown in FIG. 1A has six gas flow channels 2a. The support substrate 2 is gas permeable, allowing the fuel gas flowing in the gas flow channels 2a to permeate to the anode 3. The support substrate 2 may be conductive. The conductive support substrate 2 collects electricity generated in the element section to the interconnector 6.

[0016] The material of the support substrate 2 includes, for example, an iron group metal component and an inorganic oxide. For example, the iron group metal component may be Ni (nickel) and / or NiO. The inorganic oxide may be, for example, a specific rare earth element oxide.

[0017] A commonly known material can be used for the fuel electrode 3. The fuel electrode 3 may be made of porous conductive ceramics, such as ceramics containing calcium oxide, magnesium oxide, or ZrO2 solid-solubilized with a rare earth element oxide, and Ni and / or NiO. Examples of rare earth element oxides include Y2O3 and Yb2O3. Calcium oxide, magnesium oxide, or ZrO2 solid-solubilized with a rare earth element oxide is sometimes called stabilized zirconia. Stabilized zirconia also includes partially stabilized zirconia.

[0018] The solid electrolyte layer 4 is an electrolyte and acts as a bridge for ions between the fuel electrode 3 and the air electrode 5. At the same time, the solid electrolyte layer 4 has gas barrier properties, making it difficult for leakage of fuel gas and oxygen-containing gas to occur.

[0019] The material of solid electrolyte layer 4 may be, for example, ZrO2 in which 3 mol % to 15 mol % of a rare earth element oxide is dissolved. Examples of the rare earth element oxide include Y2O3 and Yb2O3. However, other materials may be used for solid electrolyte layer 4 as long as they have the above properties.

[0020] There are no particular restrictions on the material of the air electrode 5 as long as it is one that is generally used for air electrodes. The material of the air electrode 5 may be, for example, a conductive ceramic such as a so-called ABO3-type perovskite oxide.

[0021] The material of the air electrode 5 may be, for example, a composite oxide in which Sr and La 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. Note that x is 0 <x<1、yは0<y<1である。

[0022] The air electrode 5 is gas permeable. The open porosity of the air electrode 5 may be, for example, 20% or more, and particularly in the range of 30% to 50%.

[0023] Lanthanum chromite-based perovskite oxides (LaCrO3-based oxides), lanthanum strontium titanium-based perovskite oxides (LaSrTiO3-based oxides), etc. may be used as the material for the interconnector 6. These materials are conductive and are not reduced or oxidized even when in contact with fuel gases such as hydrogen-containing gases and oxygen-containing gases such as air.

[0024] Furthermore, the interconnector 6 is dense and makes it difficult for leakage of the fuel gas flowing through the gas flow channel 2a located inside the support substrate 2 and the oxygen-containing gas flowing outside the support substrate 2 to occur. The interconnector 6 may have a relative density of 93% or more, particularly 95% or more.

[0025] <Configuration of cell stack device> Next, a cell stack device 10 according to this embodiment using the above-described cell 1 will be described with reference to Figures 2A to 2C. Figure 2A is a perspective view showing an example of the cell stack device 10 according to this embodiment, Figure 2B is a cross-sectional view taken along line AA shown in Figure 2A, and Figure 2C is a top view showing an example of the cell stack device 10 according to this embodiment.

[0026] 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 of the cells 1 (see Fig. 1A), and a fixing member 12. Note that the cell stack 11 only needs to have one or more cells 1. Even when there is only one cell 1 as the first cell, the cell stack 11 and cell stack device 10 will be referred to for convenience.

[0027] The fixing member 12 has a bonding material 13 and a support member 14. The support member 14 supports the cell 1. The bonding material 13 bonds the cell 1 and the support member 14. The support member 14 also has a support 15 and a gas tank 16. The support 15 and the gas tank 16, which are the support member 14, are made of metal and are electrically conductive.

[0028] 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 with a joining material 13.

[0029] The gas tank 16 has an opening for supplying a reaction gas to the cells 1 through the insertion holes 15a, and a recessed groove 16a located around the opening. The outer peripheral edge of the support 15 is fixed to the gas tank 16 by a fixing material 21 filled in the recessed groove 16a of the gas tank 16.

[0030] In the example shown in Fig. 2A, fuel gas is stored in an internal space 22 formed by a support 15, which is the support member 14, and a gas tank 16. A gas circulation pipe 20 is connected to the gas tank 16. The fuel gas is supplied to the gas tank 16 through this gas circulation pipe 20, and is supplied from the gas tank 16 to a gas flow path 2a (see Fig. 1A) inside the cell 1. The fuel gas supplied to the gas tank 16 is generated in a reformer 102 (see Fig. 9), which will be described later.

[0031] The hydrogen-rich fuel gas can be produced by steam reforming the raw fuel, etc. When the fuel gas is produced by steam reforming, the fuel gas contains water vapor.

[0032] The example shown in FIG. 2A includes two rows of cell stacks 11 each having a plurality of cells 1, two supports 15, and a gas tank 16. Each of the two rows of cell stacks 11 has a plurality of cells 1. Each cell stack 11 is fixed to a respective support 15. The gas tank 16 has two through holes on its top surface. A respective support 15 is disposed in each through hole. An internal space 22 is formed by one gas tank 16 and two supports 15.

[0033] The shape of the insertion hole 15a is, for example, an oval shape when viewed from above. For example, the length of the insertion hole 15a in the arrangement direction of the cells 1, i.e., the thickness direction T, is greater 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, greater than the length of the cell 1 in the width direction W (see FIG. 1A). Note that the shape of the insertion hole 15a may also be a substantially rectangular shape that is longer in the arrangement direction of the cells 1.

[0034] 2B, a bonding material 13 is filled and solidified in the joints between the inner walls of the insertion holes 15a and the lower ends of the cells 1. This bonds and fixes the inner walls of the insertion holes 15a to the lower ends of the multiple cells 1, respectively, and also bonds and fixes the lower ends of the cells 1 to each other. The gas flow path 2a of each cell 1 communicates with the internal space 22 of the support member 14 at its lower end.

[0035] A material with low conductivity, such as glass, can be used for the bonding material 13 and the fixing material 21. Specific materials for the bonding material 13 and the fixing material 21 include amorphous glass, and in particular, crystallized glass.

[0036] As the crystallized glass, for example, any of materials such as SiO2-CaO, MgO-B2O3, La2O3-B2O3-MgO, La2O3-B2O3-ZnO, and SiO2-CaO-ZnO may be used, and in particular, SiO2-MgO materials may be used.

[0037] 2B, a conductive member 18 is interposed between adjacent cells 1 among the plurality of cells 1. The conductive member 18 electrically connects the fuel electrode 3 of one adjacent cell 1 to the air electrode 5 of the other cell 1 in series. More specifically, the conductive member 18 connects the interconnector 6 electrically connected to the fuel electrode 3 of one adjacent cell 1 to the air electrode 5 of the other cell 1.

[0038] 2B, an end current collecting member 17 is electrically connected to the cell 1 located at the outermost position in the arrangement direction of the multiple cells 1. The end current collecting member 17 is connected to a conductive part 19 that protrudes to the outside of the cell stack 11. The conductive part 19 collects electricity generated by power generation in the cells 1 and extracts it to the outside. Note that the end current collecting member 17 is not shown in FIG. 2A.

[0039] 2C, the cell stack device 10 has two cell stacks 11A and 11B connected in series to function as a single battery. Therefore, the conductive part 19 of the cell stack device 10 is divided into a positive terminal 19A, a negative terminal 19B, and a connection terminal 19C.

[0040] The positive electrode terminal 19A is a positive electrode when the power generated by the cell stack 11 is output to the outside, and is electrically connected to the positive electrode side end current collecting member 17 of the cell stack 11A. The negative electrode terminal 19B is a negative electrode when the power generated by the cell stack 11 is output to the outside, and is electrically connected to the negative electrode side end current collecting member 17 of the cell stack 11B.

[0041] The connection terminal 19C electrically connects the end current collecting member 17 on the negative electrode side of the cell stack 11A and the end current collecting member 17 on the positive electrode side of the cell stack 11B.

[0042] <Joining of support and cell> Next, the bonding between the support 15 and the cell 1 will be described with reference to Figures 3A and 3B. Figure 3A is a cross-sectional view taken along line YY in Figure 2C. Figure 3B is an enlarged cross-sectional view schematically showing a main part of the cell stack shown in Figure 3A. In Figure 3B, the surface of the substrate 151 constituting the support 15 is illustrated in a simplified planar form.

[0043] As shown in FIGS. 3A and 3B, the support 15 is bonded to the cell 1 via a bonding material 13.

[0044] The support 15 has a base material 151 and a coating layer 152. The support 15 is an example of a metal member with a coating layer. The base material 151 is electrically conductive and heat resistant. The base material 151 contains chromium. The base material 151 is, for example, stainless steel. The base material 151 is an example of a metal member. The base material 151 may contain, for example, a metal oxide.

[0045] The covering layer 152 covers the base material 151. The covering layer 152 is located so as to be in contact with the first surface 151a and the second surface 151b of the base material 151.

[0046] The coating layer 152 has a first surface 152a facing the bonding material 13 and a second surface 152b exposed to the oxidizing atmosphere (external space 23). The first surface 152a is an example of a first outer surface or a third outer surface. The second surface 152b is an example of a second outer surface or a fourth outer surface.

[0047] The material of the coating layer 152 is, for example, an inorganic oxide. The inorganic oxide may be, for example, aluminum oxide (alumina), magnesium oxide (magnesia), silicon oxide (silica), zirconium oxide (zirconia), chromium oxide (chromia), titanium oxide (titania), or a composite oxide thereof. The zirconia may be stabilized zirconia. The composite oxide may be selected from, for example, forsterite and cordierite. The material of the coating layer 152 may be a material with low conductivity or an insulating material. Using a material with low conductivity or an insulating material for the coating layer 152 allows the cell stack device 10 to have a high withstand voltage and high insulation resistance.

[0048] In particular, alumina and forsterite have a small difference in thermal expansion coefficient from base material 151, and the thermal stress caused by the temperature difference is small. Therefore, coating layer 152 can be firmly bonded to base material 151, and coating layer 152 is less likely to peel off from base material 151.

[0049] By being located between the bonding material 13 and the base material 151, the coating layer 152 relieves stress that occurs between the bonding material 13 and the base material 151 due to, for example, differences in thermal expansion coefficients, and reduces the occurrence of cracks in the bonding material 13.

[0050] Incidentally, the second surface 152b of the coating layer 152, where the bonding material 13 is not located, is exposed to the external space 23. The external space 23 is a space where the air electrode 5 (see FIG. 1) 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.

[0051] As described above, the base material 151 contains chromium (Cr). For example, if the chromium (Cr) contained in the base material 151 is desorbed into the oxidizing atmosphere (external space 23), the performance of the air electrode 5 may be reduced.

[0052] Therefore, in the embodiment, the thickness of the coating layer 152 facing the oxidizing atmosphere (external space 23) can be increased. In the embodiment, as shown in Fig. 3B, the thickness t2 of the coating layer 152 where the second surface 152b is located is greater than the thickness t1 of the coating layer 152 where the first surface 152a is located.

[0053] This makes it difficult for chromium contained in the base material 151 to be desorbed into the oxidizing atmosphere (external space 23) during high-temperature operation, for example. Therefore, according to the embodiment, the durability of the air electrode 5 can be improved, and therefore the durability of the cell stack device 10 can be improved.

[0054] On the other hand, the coating layer 152 is bonded to the bonding material 13, and depending on the operating environment, the coating layer 152 may peel off from the bonding material 13, causing fuel gas to leak through the gap between the support 15 and the bonding material 13, which may reduce the durability of the cell stack device 10.

[0055] Therefore, in the embodiment, the surface roughness of the coating layer 152 can be made larger than the surface roughness of the base material 151. Specifically, for example, the surface roughness of the first surface 152a of the coating layer 152 may be made larger than the surface roughness of the first surface 151a of the base material 151.

[0056] This can improve the adhesion between the coating layer 152 and the bonding material 13. As a result, for example, the support body 15 is less likely to peel off from the bonding material 13, making it less likely that fuel gas will leak. Therefore, according to the embodiment, the durability of the support body 15 can be improved, and therefore the durability of the cell stack device 10 can be improved.

[0057] The surface roughness of the second surface 152b of the coating layer 152 may be the same as or different from the surface roughness of the first surface 152a. The surface roughness of the second surface 151b of the base material 151 may be the same as or different from the surface roughness of the first surface 151a.

[0058] Furthermore, in the embodiment, the bonding strength between the coating layer 152 and the substrate 151 may be increased by adjusting the porosity of the coating layer 152. The thickness of the coating layer 152 located between the second surface 152b and the substrate 151 is greater than the thickness of the coating layer 152 located between the first surface 152a and the substrate 151. Therefore, a large stress is likely to be generated in the coating layer 152 located on the second surface 152b, and the coating layer 152 is more likely to peel off from the substrate 151 than the coating layer 152 located on the first surface 152a. Specifically, for example, the porosity of the coating layer 152 located between the second surface 152b and the substrate 151 (the second surface 151b of the substrate 151) can be made greater than the porosity of the coating layer 152 located between the first surface 152a and the substrate 151 (the first surface 151a of the substrate 151).

[0059] This can improve stress relaxation in the coating layer 152 facing the second surface 152b, thereby increasing the bonding strength between the coating layer 152 and the substrate 151. This makes it difficult for the coating layer 152 to peel off from the support 15, for example, and makes it difficult for chromium contained in the substrate 151 to be desorbed into the oxidizing atmosphere (external space 23). Therefore, according to the embodiment, the durability of the air electrode 5 can be improved, and therefore the durability of the cell stack device 10 can be improved.

[0060] Furthermore, in the embodiment, the bonding strength between the coating layer 152 and the bonding material 13 may be increased by adjusting the content of metal elements located at the interface between the base material 151 and the coating layer 152. Specifically, for example, at least one element selected from Mn, Ti, Ca, and Al is located on the first surface 151a and the second surface 151b corresponding to the interface between the base material 151 and the coating layer 152. Furthermore, when the coating layer 152 does not contain any of Mn, Ti, Ca, and Al as a main component, the content of Mn, Ti, Ca, and Al located on the first surface 151a and the second surface 151b may be greater than the content of Mn, Ti, Ca, and Al located on the base material 151 and the coating layer 152. These metal elements may be interdiffused between the base material 151 and the coating layer 152.

[0061] This can improve adhesion between the base material 151 and the coating layer 152. As a result, for example, the base material 151 and the coating layer 152 are less likely to peel off, making it less likely that fuel gas will leak. Therefore, according to the embodiment, the durability of the support body 15 can be improved, and therefore the durability of the cell stack device 10 can be improved.

[0062] The metal element located at the interface between the substrate 151 and the coating layer 152 may be located as a simple substance, an alloy, a metal oxide, or a composite oxide. The metal element may be located on either the substrate 151 side or the coating layer 152 side, or may be located so as to straddle the substrate 151 and the coating layer 152.

[0063] In particular, Mn may be located in the protruding portions of the substrate 151 or in the recessed portions or pores of the coating layer 152. Ti may be located in the recessed portions of the substrate 151 or in the pores of the coating layer 152. Ca may be located in the protruding portions of the substrate 151 or in the recessed portions or pores of the coating layer 152. Al may be located in the protruding portions of the substrate 151 or in the recessed portions or pores of the coating layer 152.

[0064] <Joining of support body and end current collecting member> Next, the joining of the support body 15 and the end current collecting member 17 will be described with reference to Fig. 4. Fig. 4 is a cross-sectional view taken along line ZZ shown in Fig. 2C.

[0065] As shown in FIG. 4, the end current collecting member 17 is joined to the support body 15 via the joining material 13 .

[0066] End current collecting member 17 has base material 171 and coating material 172. By covering the surface of end current collecting member 17 with coating material 172, it is possible to make it difficult for chromium (Cr) contained in base material 171 to be released into an oxidizing atmosphere (external space 23) during high-temperature operation, for example, and therefore the durability of end current collecting member 17 can be improved.

[0067] The base material 171 is, for example, a conductive material containing chromium (Cr). The base material 171 may also be, for example, stainless steel.

[0068] The material of the coating material 172 may be, for example, an inorganic oxide. The coating material 172 may be a conductive oxide containing manganese (Mn) (for example, Mn 1.5 CO 1.5 The coating material 172 may be formed on the surface of the base material 171 by, for example, electrodeposition coating.

[0069] The coating material 172 coats the base material 171. The coating material 172 is positioned so as to cover the surfaces 171a and 171b of the base material 171. The coating material 172 has a surface 172a that faces the bonding material 13 and a surface 172b that is exposed to the oxidizing atmosphere (external space 23).

[0070] By being positioned between the bonding material 13 and the base material 171, the coating material 172 relieves stress that occurs between the bonding material 13 and the base material 171 due to, for example, differences in thermal expansion coefficients, thereby reducing the occurrence of cracks in the bonding material 13.

[0071] The base material 171 also has a surface 171c adjacent to the surface 171a and facing the bonding material 13. That is, one end (lower end) 172e of the covering material 172 faces the bonding material 13 and does not face the internal space 22.

[0072] In the embodiment, the surface roughness of the covering material 172 facing the bonding material 13 can be made larger than the surface roughness of the covering material 172 not facing the bonding material 13. Specifically, for example, the surface roughness of the surface 172a of the covering material 172 may be made larger than the surface roughness of the surface 172b.

[0073] This can improve the adhesion between the covering material 172 and the bonding material 13. As a result, for example, the end current collecting member 17 is less likely to peel off from the bonding material 13, making it less likely that fuel gas will leak. Therefore, according to the embodiment, the durability of the end current collecting member 17 can be improved, and therefore the durability of the cell stack device 10 can be improved.

[0074] In addition, in the embodiment, the surface roughness of the base material 171 facing the bonding material 13 can be made larger than the surface roughness of the coating material 172 facing the bonding material 13. Specifically, for example, the surface roughness of the surface 171c of the base material 171 may be made larger than the surface roughness of the surface 172a.

[0075] This can improve the adhesion between the end current collecting member 17 and the bonding material 13. Therefore, for example, the end current collecting member 17 is less likely to peel off from the bonding material 13, making it less likely that fuel gas will leak. Therefore, according to the embodiment, the durability of the end current collecting member 17 can be improved, and therefore the durability of the cell stack device 10 can be improved.

[0076] Furthermore, by making the surface roughness of the surface 172a smaller than the surface roughness of the surface 171c, for example, during high-temperature operation, it is possible to make it difficult for chromium contained in the base material 171 to be desorbed into the oxidizing atmosphere (external space 23) via the coating material 172. Therefore, according to the embodiment, the durability of the end current collecting member 17 can be increased, and therefore the durability of the cell stack device 10 can be increased.

[0077] Furthermore, in the embodiment, the area of ​​the surface 171c may be smaller than the area of ​​the surface 172a. Specifically, for example, the area S2 of the surface 171c may be smaller than the area S1 of the surface 172a.

[0078] This makes it difficult for chromium contained in the base material 171 to be desorbed into the oxidizing atmosphere (external space 23) through the coating material 172 during high-temperature operation, and also makes it difficult for the end current collecting member 17 to peel off from the bonding material 13, thereby making it difficult for fuel gas to leak. Therefore, according to the embodiment, the durability of the end current collecting member 17 can be increased, and therefore the durability of the cell stack device 10 can be increased.

[0079] The surface roughness of surface 171b of base material 171 can be made smaller than the surface roughness of surface 171a. For example, if the surface roughness of surface 171b is made smaller than the surface roughness of surface 171a, it becomes possible to make it difficult for chromium contained in base material 171 to be desorbed into the oxidizing atmosphere (external space 23) through surface 171b of coating material 172 during high-temperature operation, for example. The surface roughnesses of surfaces 171a and 171b may be the same.

[0080] Furthermore, the base material 171 may have an oxide layer 173 located so as to face the coating material 172 and the bonding material 13. The oxide layer 173 may be, for example, a natural oxide film made of chromium oxide (Cr2O3).

[0081] The oxide layer 173 hardly causes a reduction reaction of the constituent elements, even in a reducing atmosphere, for example. By having the oxide layer 173, for example, it is possible to make it difficult for the constituent elements of the base material 171 to be desorbed from the surface exposed to the reducing atmosphere (internal space 22). Therefore, according to the embodiment, the durability of the end current collecting member 17 can be improved, and therefore the durability of the cell stack device 10 can be improved.

[0082] 2C, the support 15 is positioned so as to surround the periphery of the bonding material 13 filling the insertion hole 15a, which has an oval shape in top view. The insertion hole 15a of the support 15 has a linear portion (first portion 15A) that extends linearly along the arrangement direction of the cells 1 as a first direction, i.e., the thickness direction T (see FIG. 1A), and a bent portion (second portion 15B) that bends from the first direction. The cell 1 is positioned so as to face the first portion 15A of the support 15, and the end current collecting member 17 is positioned so as to face the second portion 15B of the support 15.

[0083] In the embodiment, the thickness of the covering layer 152 located in the second portion 15B of the support 15 may be greater than the thickness of the covering layer 152 located in the first portion 15A. Specifically, the thickness t1 (see FIG. 3B) of the covering layer 152 where the first surface 152a is located is greater in the second portion 15B than in the first portion 15A.

[0084] In the second portion 15B of the support body 15, which is bent in top view, stress due to differences in thermal expansion of the components is more likely to concentrate than in the first portion 15A. In this way, by varying the thickness of the covering layer 152 where the first surface 152a is located depending on the shape of the support body 15, particularly the insertion hole 15a, in top view, it is possible to alleviate stress concentration in, for example, the second portion 15B. Therefore, according to the embodiment, the durability of the support body 15 can be improved, and therefore the durability of the cell stack device 10 can be improved.

[0085] In the embodiment, the inner surface 151e is described as being exposed to the reducing atmosphere (internal space 22), but this is not limiting, and for example, the inner surface 151e may have a coating layer positioned so as to cover it.

[0086] <Various modified examples> Next, support bodies 15 according to various modified examples of the embodiment will be described with reference to Figures 5A to 7B. Figures 5A and 5B are perspective views showing other examples of metal members.

[0087] When a flat support 15 as shown in Fig. 5A is used, for example, a gas tank 16 (see Fig. 2A) is joined to the underside or side of the flat support 15 to form an internal space 22 (see Fig. 4C). The support 15 shown in Fig. 5B has a plurality of insertion holes 15a. In this case, one cell 1 may be inserted into each of the plurality of insertion holes 15a of the support 15, or a plurality of cells 1 may be inserted into each of the plurality of insertion holes 15a of the support 15.

[0088] 5C is an enlarged cross-sectional view of the joint between another example of the metal member and the cell. As shown in FIG. 5C, the support 15 has a flat plate shape. The support 15 is joined to the cell 1 via the joining material 13.

[0089] The support 15 has a base material 151 and a coating layer 152. The base material 151 has a first surface 151a, a second surface 151b, and an inner surface 151e. The first surface 151a and the second surface 151b face the coating layer 152. The inner surface 151e faces the reducing atmosphere (internal space 22).

[0090] The coating layer 152 coats the base material 151. The coating layer 152 is located between a first surface 151a of the base material 151 and the bonding material 13. The coating layer 152 is also located between a second surface 151b of the base material 151 and the oxidizing atmosphere (external space 23). The coating layer 152 has a first surface 152a and a second surface 152b. The first surface 151a faces the bonding material 13. The second surface 151b faces the oxidizing atmosphere (external space 23).

[0091] The bonding material 13 bonds the cell 1 to the support 15. The bonding material 13 is located between the solid electrolyte layer 4 (see FIG. 1A) of the cell 1 and the coating layer 152 of the support 15, and bonds the cell 1 to a first surface 152a serving as a first outer surface of the coating layer 152.

[0092] In the support 15 of the embodiment, the thickness t2 of the coating layer 152 where the second surface 152b of the coating layer 152 exposed to the oxidizing atmosphere (external space 23) is located is greater than the thickness t1 of the coating layer 152 where the first surface 152a facing the bonding material 13 is located.

[0093] This makes it difficult for chromium contained in the base material 151 to be desorbed into the oxidizing atmosphere (external space 23) during high-temperature operation, for example. Therefore, according to the embodiment, the durability of the air electrode 5 can be improved, and therefore the durability of the cell stack device 10 can be improved.

[0094] On the other hand, the coating layer 152 is bonded to the bonding material 13, and depending on the operating environment, the coating layer 152 may peel off from the bonding material 13, causing a gap between the support 15 and the bonding material 13 to leak fuel gas, which may reduce the durability of the cell stack device 10.

[0095] Therefore, in the embodiment, the surface roughness of the coating layer 152 can be made larger than the surface roughness of the base material 151. Specifically, for example, the surface roughness of the first surface 152a of the coating layer 152 may be made larger than the surface roughness of the first surface 151a and the second surface 151b of the base material 151.

[0096] This can improve the adhesion between the coating layer 152 and the bonding material 13. As a result, for example, the support body 15 is less likely to peel off from the bonding material 13, making it less likely that fuel gas will leak. Therefore, according to the embodiment, the durability of the support body 15 can be improved, and therefore the durability of the cell stack device 10 can be improved.

[0097] The surface roughness of the second surface 151b of the base material 151 may be the same as or different from the surface roughness of the first surface 151a. The surface roughness of the second surface 152b of the coating layer 152 may be the same as or different from the surface roughness of the first surface 152a. For example, the surface roughness of the second surface 152b may be smaller than that of the first surface 152a. This makes it difficult for chromium (Cr) contained in the base material 151 to be desorbed into the oxidizing atmosphere (external space 23) via the second surface 152b of the coating layer 152, for example, during high-temperature operation. This therefore increases the durability of the support 15, thereby increasing the durability of the cell stack device 10.

[0098] In the embodiment, the bonding strength between the coating layer 152 and the bonding material 13 may be increased by adjusting the porosity of the coating layer 152. Specifically, for example, the porosity of the coating layer 152 located between the second surface 152b and the second surface 151b of the base material 151 can be made larger than the porosity of the coating layer 152 located between the first surface 152a and the first surface 151a of the base material 151.

[0099] This can improve stress relaxation in the coating layer 152 facing the second surface 152b, thereby increasing the bonding strength between the coating layer 152 and the bonding material 13. This makes it difficult for the support 15 to peel off from the bonding material 13, making it difficult for fuel gas to leak. Therefore, according to the embodiment, the durability of the support 15 can be improved, and therefore the durability of the cell stack device 10 can be improved.

[0100] Furthermore, in the embodiment, the bonding strength between the coating layer 152 and the bonding material 13 may be increased by adjusting the content of a metal element located at the interface between the base material 151 and the coating layer 152. Specifically, for example, at least one element selected from Mn, Ti, Ca, and Al is located on the first surface 151a and the second surface 151b, which correspond to the interface between the base material 151 and the coating layer 152. The content of Mn, Ti, Ca, and Al located on the first surface 151a and the second surface 151b may be greater than the content of Mn, Ti, Ca, and Al located on the base material 151 and the coating layer 152.

[0101] This can improve adhesion between the base material 151 and the coating layer 152. As a result, for example, the base material 151 and the coating layer 152 are less likely to peel off, making it less likely that fuel gas will leak. Therefore, according to the embodiment, the durability of the support body 15 can be improved, and therefore the durability of the cell stack device 10 can be improved.

[0102] The metal element located at the interface between the substrate 151 and the coating layer 152 can be located as a simple substance, an alloy, or a metal oxide. The metal element may be located on either the substrate 151 side or the coating layer 152 side, or may be located so as to straddle the substrate 151 and the coating layer 152.

[0103] Furthermore, the insertion hole 15a of the support 15 shown in Figure 5B has a first portion 15A extending in the width direction W of the cell 1 (see Figure 1A), a second portion 15B bending from the first direction, and a third portion 15C extending in the arrangement direction of the cell 1, i.e., the thickness direction T (see Figure 1A).

[0104] In the embodiment, the thickness of the covering layer 152 located in the second portion 15B of the support 15 may be greater than the thickness of the covering layer 152 located in the first portion 15A and the third portion 15C. Specifically, the thickness t1 (see FIG. 5C ) of the covering layer 152 where the first surface 152a is located is greater in the second portion 15B than in the first portion 15A and the third portion 15C.

[0105] In the second portion 15B of the support body 15, which is bent in top view, stress due to differences in thermal expansion of the respective members is more likely to concentrate than in the first portion 15A and the third portion 15C. In this way, by varying the thickness of the coating layer 152 according to the shape of the support body 15, particularly the insertion hole 15a, in top view, it is possible to alleviate stress concentration on the first surface 152a, for example, according to the second portion 15B. Therefore, according to the embodiment, the durability of the support body 15 can be improved, and therefore the durability of the cell stack device 10 can be improved.

[0106] 6A to 6E are enlarged cross-sectional views of the joint between the cell and the metal member according to Modifications 1 to 5 of the embodiment. Figures 7A and 7B are enlarged cross-sectional views of the joint between the cell and another example of the metal member according to Modifications 6 and 7 of the embodiment.

[0107] As shown in FIGS. 6A and 7A, the coating layer 152 of the support 15 may further have an intermediate surface 152c located between the first surface 152a and the second surface 152b.

[0108] The intermediate surface 152c faces the coating layer 152. The intermediate surface 152c may have a smaller surface roughness than the first surface 152a. The intermediate surface 152c is located closer to the oxidizing atmosphere than the first surface 152a. By making the surface roughness of the intermediate surface 152c smaller than that of the first surface 152a, which is located farther from the oxidizing atmosphere among the coating layer 152 facing the bonding material 13, it is possible to, for example, make it less likely that chromium (Cr) contained in the base material 151 will be desorbed into the oxidizing atmosphere (external space 23) through the coating layer 152 during high-temperature operation. Therefore, according to the embodiment, the durability of the support 15 can be improved, thereby improving the durability of the cell stack device 10. Note that the surface roughness of the coating layer 152 located at the intermediate surface 152c may be the same as that of the second surface 152b, for example. Alternatively, the intermediate surface 152c may have a surface roughness intermediate between that of the first surface 152a and that of the second surface 152b, for example.

[0109] Furthermore, the coating layer 152 where the intermediate surface 152c is located may be thicker than the coating layer 152 where the first surface 152a is located. The intermediate surface 152c is located closer to the oxidizing atmosphere than the first surface 152a. By making the thickness of the intermediate surface 152c of the coating layer 152 facing the bonding material 13 thicker than the first surface 152a, which is located farther from the oxidizing atmosphere, it is possible to, for example, make it less likely that chromium (Cr) contained in the base material 151 will be desorbed into the oxidizing atmosphere (external space 23) through the coating layer 152 during high-temperature operation. Therefore, according to the embodiment, the durability of the support 15 can be improved, and therefore the durability of the cell stack device 10 can be improved. Note that the thickness of the coating layer 152 located at the intermediate surface 152c may be the same as the thickness t2 of the second surface 152b (see FIG. 3B), for example. Furthermore, the intermediate surface 152c may have a thickness intermediate between the thicknesses t1 and t2.

[0110] On the other hand, as shown in FIGS. 6B and 7B, the covering layer 152 of the support 15 may further have an intermediate surface 152d located between the first surface 152a and the second surface 152b.

[0111] The intermediate surface 152d is exposed to the oxidizing atmosphere (external space 23). The intermediate surface 152d has a surface roughness greater than that of the second surface 152b, for example. Even when the intermediate surface 152d is provided, it is possible to make it difficult for chromium (Cr) contained in the base material 151 to be desorbed into the oxidizing atmosphere (external space 23), for example, during high-temperature operation. Therefore, according to the embodiment, the durability of the support 15 can be improved, and therefore the durability of the cell stack device 10 can be improved. Note that the surface roughness of the intermediate surface 152d may be the same as that of the first surface 152a, for example. Alternatively, the intermediate surface 152d may have a surface roughness intermediate between that of the first surface 152a and that of the second surface 152b, for example.

[0112] Furthermore, in each of the modified examples shown in FIGS. 6A, 6B, 7A, and 7B, examples have been shown in which only one of the intermediate surfaces 152c and 152d is provided, but both the intermediate surfaces 152c and 152d may be provided.

[0113] Furthermore, as shown in FIG. 6C, second surface 152b of coating layer 152 exposed to the oxidizing atmosphere (external space 23) may have surfaces 152b1 and 152b2 of coating layer 152 with different thicknesses.

[0114] The surface 152b2 is located farther from the element portion of the cell 1 than the surface 152b1. The surface 152b1 closer to the element portion is more likely to reach a higher temperature than the surface 152b2 further from the element portion, and chromium (Cr) contained in the base material 151 is more likely to be desorbed into the oxidizing atmosphere (external space 23). Therefore, the thickness of the coating layer 152 where the surface 152b1 is located can be made larger than the thickness of the coating layer 152 where the surface 152b2 further from the element portion is located.

[0115] By making the thickness of the coating layer 152 where the surface 152b1 is located greater than the thickness of the coating layer 152 where the surface 152b2 is located, it is possible to make it difficult for chromium (Cr) contained in the base material 151 to be desorbed into the oxidizing atmosphere (external space 23) during high-temperature operation, for example. Therefore, according to the embodiment, the durability of the support 15 can be increased, and therefore the durability of the cell stack device 10 can be increased.

[0116] Furthermore, the surface roughness of the surface 152b1 close to the element unit may be greater than the surface roughness of the surface 152b2 away from the element unit. By increasing the surface roughness of the surface 152b1, the flow of the oxygen-containing gas (air) near the element unit can be changed, thereby lengthening the residence time of the oxygen-containing gas (air). Therefore, according to the embodiment, the intake of oxygen by the air electrode 5 can be promoted, thereby improving the reaction efficiency of the cell stack device 10.

[0117] In the example shown in FIG. 6C, the boundary between surfaces 152b1 and 152b2 is located at the upper end portion of support body 15, but this is not limited thereto. For example, as shown in FIG. 2C, the upper surface visible when viewing cell stack device 10 from above may be surface 152b1, and the side surface located to the side of surface 152b1 may be surface 152b2. Also, the portion whose temperature reaches a predetermined value or higher during high-temperature operation may be surface 152b1, and the other portion may be surface 152b2. Furthermore, the portion facing a flow path (not shown) for oxygen-containing gas (air) may be surface 152b1, and the other portion may be surface 152b2.

[0118] 6D, the covering layer 152 of the support body 15 may further have a connecting surface 152f located between the first surface 152a and the second surface 152b. The connecting surface 152f continuously connects the first surface 152a and the second surface 152b by gradually varying the thickness of the covering layer 152. By having the covering layer 152 have the connecting surface 152f in this way, the durability of the support body 15 can be increased, and therefore the durability of the cell stack device 10 can be increased.

[0119] The connection surface 152f may face the bonding material 13 together with the first surface 152a. The connection surface 152f may be exposed to the oxidizing atmosphere (external space 23) together with the second surface 152b. Furthermore, the connection surface 152f may have a portion facing the bonding material 13 and a portion exposed to the oxidizing atmosphere (external space 23).

[0120] 6E, the thickness of the coating layer 152 may be constant. Even in such a case, by making the surface roughness of the first surface 152a and the second surface 152b different as described above, the durability of the support body 15 can be increased, and therefore the durability of the cell stack device 10 can be increased. Furthermore, by making the porosity of the coating layer 152 in the portions P1 and P2 where the first surface 152a and the second surface 152b are located, respectively, different as described above, the durability of the support body 15 can be increased, and therefore the durability of the cell stack device 10 can be increased.

[0121] 6E, a surface 152g located between the first surface 152a and the second surface 152b may have a surface roughness intermediate between that of the first surface 152a and that of the second surface 152b. The porosity of a portion P3 of the coating layer 152 where the surface 152g is located may be intermediate between that of portions P1 and P2. By positioning the surface 152g in this manner, the durability of the support body 15 can be increased, and therefore the durability of the cell stack device 10 can be increased.

[0122] Fig. 8A is a front view showing an end current collecting member according to Modification 8 of the embodiment, and Fig. 8B is a cross-sectional view showing an end current collecting member according to Modification 9 of the embodiment.

[0123] As shown in FIG. 8A, upper ends 17a of end current collecting members 17 that can be seen when viewed from above may have rounded corners 17a1.

[0124] 8B, the lower end 17b of the end current collecting member 17 has an end face 17f that is inclined with respect to the arrangement direction of the cells 1, and is therefore positioned so that the width of the end 17e is smaller than the thickness of the end current collecting member 17. This allows the end current collecting member 17 to be smoothly inserted into the bonding material 13 before solidification.

[0125] 8C and 8D are enlarged cross-sectional views of the joint between the end current collecting member and the metal member according to Modifications 10 and 11 of the embodiment.

[0126] As shown in FIG. 8C, the covering material 172 may be located at one end (lower end) 172e of the covering material 172 of the end current collecting member 17, and may have a surface 172f connecting the surface 171a (surface 171c) of the base material 171 and the surface 172a of the covering material 172.

[0127] Also, as shown in FIG. 8D, the covering material 172 may be located on one end (lower end) 172e side of the covering material 172 of the end current collecting member 17, protrude in a direction away from the surface 172a, and have a protrusion 172g facing the bonding material 13.

[0128] By providing the covering material 172 with the surface 172f or the protruding portion 172g in this manner, the contact area between the covering material 172 and the bonding material 13 is increased. This increases the durability of the end current collecting member 17, thereby increasing the durability of the cell stack device 10. Note that although Figures 8C and 8D illustrate the covering material 172 as having the surface 172f or the protruding portion 172g, the covering material 172 may also have the surface 172f and the protruding portion 172g.

[0129] <Evaluation method> Here, the thickness of each surface of the support 15 and the end current collecting member 17 described above and each surface described below is calculated by image analysis of a cross section perpendicular to each surface. First, the support 15 and the bonding material 13, or the end current collecting member 17 and the bonding material 13, are cut out and embedded in resin, and the cross section perpendicular to the surface whose surface roughness is to be measured is polished using abrasive grains, lapping film (approximately #8000), etc. to obtain a mirror-finished cross section. The obtained cross section is photographed using an SEM (scanning electron microscope), an optical microscope, etc., and the obtained image is analyzed to measure the thickness of each surface.

[0130] The surface roughness of each surface of the support 15 and the end current collecting member 17 described above and each surface described below can be determined based on the arithmetic mean roughness Ra specified in JIS B0633; 2001. The arithmetic mean roughness Ra can be calculated by image analysis of a cross section perpendicular to each surface, similar to the thickness of each surface.

[0131] In addition, the porosity of each part of the coating layer 152 can be calculated, for example, by analyzing an image of the cross section of each part of the coating layer 152 observed with an SEM (scanning electron microscope) and calculating it as the ratio of the total area of ​​the pores to the area of ​​the entire image.

[0132] The Mn, Ti, Ca, and Al contents in each portion of the support 15 can be confirmed by, for example, cutting or scraping each portion of the support 15 from the cell 1 and performing elemental analysis such as ICP optical emission spectroscopy. Alternatively, the contents can be calculated by performing elemental analysis on a cross section of the support 15 using an electron probe microanalyzer (EPMA), wavelength dispersive X-ray spectroscopy (WDS), energy dispersive X-ray spectroscopy (EDS), or the like.

[0133] (Coating layer thickness) The thickness of the coating layer 152 calculated as above can be set to, for example, 2 μm to 400 μm on average over the entire support 15.

[0134] (Surface roughness of each surface) The surface roughness (arithmetic mean roughness Ra) of each surface calculated as described above may be, for example, 0.1 μm to 30 μm. The surface roughness (arithmetic mean roughness Ra) of one of the first surface 152a and the second surface 152b may be, for example, 0.1 μm to 30 μm. Furthermore, the surfaces described below may also have a surface roughness (arithmetic mean roughness Ra) similar to that of the surfaces described above.

[0135] (Porosity of coating layer) The porosity of the coating layer 152 calculated as above and the coating layer described below can be, for example, 10% to 40% by area on average across the entire support 15.

[0136] The coating layer 152 may have cracks with an opening width of, for example, 10 μm or less. The bonding material 13 may be located inside the cracks. By having the bonding material 13 located inside the cracks, for example, the durability of the support body 15 can be increased, and therefore the durability of the cell stack device 10 can be increased.

[0137] (Mn, Ti, Ca and Al content) The Mn, Ti, Ca, and Al contents in support 15 and a support member described below calculated as above can be, for example, 0.01% to 10% by mass on average throughout support 15. The Mn, Ti, Ca, and Al contents in the interface between substrate 151 and coating layer 152, substrate 151, and coating layer 152 can be, for example, 0.1% to 30% by mass (interface), 0.01% to 10% by mass (substrate 151), and 0.01% to 10% by mass (coating layer 152), respectively.

[0138] (Manufacturing method) The coating layer 152 according to the embodiment can be formed by, for example, a thermal spraying method, a vapor deposition method, an electrodeposition method, a sputtering method, etc. Alternatively, the coating layer 152 may be formed by, for example, applying a coating material to the surface of the base material 151 and then baking the applied coating material.

[0139] The first surface 152a and the second surface 152b of the coating layer 152 can be formed, for example, based on the difference in surface roughness between the first surface 151a and the second surface 151b of the base material 151, which correspond to the first surface 152a and the second surface 152b. Alternatively, the thickness of the portion corresponding to the second surface 152b may be made greater than the thickness of the portion corresponding to the first surface 152a. Alternatively, the second surface 152b may be formed by polishing the portion of the surface of the coating layer 152 corresponding to the second surface 152b, and the remaining portion may be the first surface 152a. The first surface 152a and the second surface 152b may be formed by changing the various conditions used in forming the coating layer 152. The other surfaces may also be formed by appropriately combining the manufacturing methods for the first surface 152a and the second surface 152b described above and known techniques.

[0140] <module> Next, a module 100 according to an embodiment of the present disclosure using the above-described cell stack device 10 will be described with reference to Fig. 9. Fig. 9 is an external perspective view showing the module according to the embodiment, with the front and rear surfaces, which are part of the storage container 101, removed and the cell stack device 10 of the fuel cell stored inside removed to the rear.

[0141] 9, the module 100 includes a storage container 101 and a cell stack device 10 housed in the storage container 101. A reformer 102 is disposed above the cell stack device 10.

[0142] The reformer 102 reforms raw fuel such as natural gas or kerosene to generate fuel gas, which is then supplied to the cell 1. The raw fuel is supplied to the reformer 102 through a raw fuel supply pipe 103. The reformer 102 may include a vaporizer 102a that vaporizes water, and a reformer 102b. The reformer 102b includes a reforming catalyst (not shown) and reforms the raw fuel into fuel gas. Such a reformer 102 can perform steam reforming, which is a highly efficient reforming reaction.

[0143] The fuel gas produced in the reformer 102 is supplied to the gas flow channel 2a of the cell 1 (see FIG. 1A) through the gas distribution pipe 20, the gas tank 16, and the support member 14.

[0144] Furthermore, in the module 100 having the above-described configuration, the temperature inside the module 100 during normal power generation becomes approximately 500°C to 1000°C due to the combustion of gas and the power generation of the cells 1.

[0145] In such a module 100, as described above, by accommodating the cell stack device 10 that reduces the degradation of battery performance, the module 100 can be made to reduce the degradation of battery performance.

[0146] <Module storage device> Fig. 10 is an exploded perspective view showing an example of a module housing device according to an embodiment. The module housing device 110 according to the embodiment includes an outer case 111, the module 100 shown in Fig. 11, and auxiliary equipment (not shown). The auxiliary equipment operates the module 100. The module 100 and the auxiliary equipment are housed in the outer case 111. Note that some components are omitted in Fig. 10.

[0147] An exterior case 111 of a module accommodating device 110 shown in Fig. 10 has support columns 112 and an exterior plate 113. A partition plate 114 divides the interior of the exterior case 111 into upper and lower sections. The space above the partition plate 114 in the exterior case 111 is a module accommodating chamber 115 that accommodates the module 100, and the space below the partition plate 114 in the exterior case 111 is an accessory accommodating chamber 116 that accommodates accessories that operate the module 100. Note that in Fig. 10, the accessories accommodated in the accessory accommodating chamber 116 are omitted from the illustration.

[0148] The partition plate 114 also has an air flow port 117 for allowing air from the auxiliary equipment housing chamber 116 to flow toward the module housing chamber 115. The exterior plate 113 that constitutes the module housing chamber 115 has an exhaust port 118 for exhausting air from within the module housing chamber 115.

[0149] In such a module accommodating device 110, as described above, the module 100 that reduces the degradation of battery performance is provided in the module accommodating chamber 115, thereby making it possible to make the module accommodating device 110 reduce the degradation of battery performance.

[0150] <Other variations> Next, a cell stack device according to another modified example of the embodiment will be described with reference to FIGS. 11A to 11C.

[0151] In the above-described embodiment, a so-called "vertical stripe type" cell is exemplified, in which only one element unit including a fuel electrode, a solid electrolyte layer, and an air electrode is provided on the surface of a support substrate. However, the present invention can also be applied to a horizontal stripe type cell stack device in which so-called "horizontal stripe type" cells are stacked, in which element units are provided at multiple locations spaced apart from each other on the surface of a support substrate, and adjacent element units are electrically connected.

[0152] In addition, although the present embodiment illustrates the use of a hollow flat-plate type support substrate, the present invention can also be applied to a cell stack device that uses a cylindrical support substrate. Furthermore, as will be described later, the present invention can also be applied to a flat-plate type cell stack device in which so-called "flat-plate type" cells are stacked in the thickness direction.

[0153] In addition, in the above embodiment, an example was shown in which the fuel electrode was provided on the support substrate and the air electrode was arranged on the surface of the cell, but the present invention can also be applied to a cell stack device in which the opposite arrangement is used, i.e., the air electrode is provided on the support substrate and the fuel electrode is arranged on the surface of the cell.

[0154] In addition, in the above embodiments, a fuel cell, a fuel cell stack device, a fuel cell module, and a fuel cell device are shown as examples of a "cell," a "cell stack device," a "module," and a "module accommodating device," but other examples may be an electrolytic cell, an electrolytic cell stack device, an electrolytic module, and an electrolytic device, respectively.

[0155] Fig. 11A is a perspective view showing a flat cell according to Modification 12 of the embodiment, Fig. 11B is a partial cross-sectional view of the flat cell shown in Fig. 11A, and Fig. 11C is an enlarged view of region A shown in Fig. 11B.

[0156] As shown in FIG. 11A, the cell stack device has a cell 1A in which an anode 3, a solid electrolyte layer 4, and an air electrode 5 are stacked. Furthermore, as shown in FIG. 11B, the cell 1A has an element unit 90 in which the solid electrolyte layer 4 is sandwiched between the anode 3 and the air electrode 5. In a cell stack device in which a plurality of flat-type cells are stacked, for example, the element units 90 of the plurality of cells 1A are electrically connected by conductive members 91, 92, which are adjacent metal layers. The conductive members 91, 92 electrically connect the element units 90 of adjacent cells 1A and have gas flow paths that supply gas to the anode 3 or the air electrode 5.

[0157] 11B, the flat cell stack has a sealing material that airtightly seals a fuel gas flow path 98 and an oxygen-containing gas flow path 97. The sealing material is a fixing member 96 for the cells, and has a bonding material 93 and support members 94 and 95 that serve as a frame. The bonding material 93 may be glass or a metal material such as silver solder.

[0158] The support member 94 may be a so-called separator that separates the fuel gas flow path 98 from the oxygen-containing gas flow path 97. The material of the support members 94, 95 may be, for example, a conductive metal or an insulating ceramic. If the bonding material 93 is an insulating material, such as glass, both of the support members 94, 95 may be metal, or one of them may be an insulating material. If the bonding material 93 is a conductive metal, both or one of the support members 94, 95 may be an insulating material. If the support members 94, 95 are metal, the support members 94, 95 may be integrated with the conductive member 92.

[0159] Either the bonding material 93 or the support members 94 and 95 is insulating, and electrically insulates the two conductive members 91 and 92 that sandwich the flat cell from each other.

[0160] As shown in FIG. 11C , the flat cell according to this modification includes a support member 94 and a bonding material 93. The support member 94 includes a base material 941 and a covering layer 942. The base material 941 has a first surface 941a and a second surface 941b and contains chromium. The covering layer 942 covers the first surface 941a and the second surface 941b of the base material 941. The bonding material 93 is located between the solid electrolyte layer 4 of the element section 90 and the first surface 942a of the covering layer 942.

[0161] The second surface 942b of the coating layer 942 is exposed to the oxidizing atmosphere (flow path 97). The thickness of the coating layer 942 where the second surface 942b is located is greater than the thickness of the coating layer 942 where the first surface 942a is located. This makes it difficult for chromium (Cr) contained in the base material 941 to be desorbed into the oxidizing atmosphere (flow path 97) during high-temperature operation. Therefore, according to the embodiment, the durability of the support member 94 can be improved, and therefore the durability of the cell stack device can be improved.

[0162] Furthermore, the surface roughness of the first surface 942a may be greater than the surface roughness of the second surface 942b. This makes it difficult for the coating layer 942 to peel off from the bonding material 93 or for the bonding material 93 to break, thereby preventing fuel gas leakage. Therefore, according to the embodiment, the durability of the support member 94 can be improved.

[0163] Furthermore, the porosity of the coating layer 942 where the second surface 942b is located may be greater than the porosity of the coating layer 942 where the first surface 942a is located. This makes it difficult for chromium (Cr) contained in the base material 941 to be desorbed into the oxidizing atmosphere (flow path 97) through the coating layer 942 during high-temperature operation. Therefore, according to the embodiment, the durability of the support member 94 can be increased, and therefore the durability of the cell stack device can be increased.

[0164] In the example shown in Figure 11C, the coating layer 942 is positioned so as to cover the surface 941e of the substrate 941 facing the reducing atmosphere (flow path 98), but this is not limited thereto, and the surface 941e may be exposed to the reducing atmosphere (flow path 98).

[0165] The present disclosure has been described in detail above, but the present disclosure is not limited to the above-described embodiments, and various modifications, improvements, etc. are possible within the scope that does not deviate from the gist of the present disclosure.

[0166] As described above, the metal member with a coating layer according to the embodiment includes a metal member (substrate 151) and a coating layer 152. The metal member (substrate 151) contains chromium. The coating layer 152 covers the metal member (substrate 151). The coating layer 152 has a second outer surface exposed to an oxidizing atmosphere and a first outer surface located away from the oxidizing atmosphere. The thickness of the coating layer 152 where the second outer surface is located is greater than the thickness of the coating layer where the first outer surface is located, or the surface roughness of the second outer surface is smaller than the surface roughness of the first outer surface. This can increase the durability of the metal member with a coating layer.

[0167] The disclosed embodiments should be considered in all respects as illustrative and not restrictive. Indeed, the above-described embodiments may be embodied in various forms. Furthermore, the above-described embodiments may be omitted, substituted, or modified in various ways without departing from the scope and spirit of the appended claims. [Explanation of symbols]

[0168] 1 cell 10 Cell stack device 11 Cell stack 12 Fixing member 13 Bonding material 14 Support member 15 Support 16 Gas Tank 17 End current collecting member 18 Conductive material 23 Exterior Space 100 modules 110 Module storage device

Claims

1. a metal member containing chromium; a coating layer that covers the metal member; Equipped with the coating layer has a second outer surface exposed to an oxidizing atmosphere and a first outer surface located away from the oxidizing atmosphere; The thickness of the coating layer where the second outer surface is located is greater than the thickness of the coating layer where the first outer surface is located, or the surface roughness of the second outer surface is smaller than the surface roughness of the first outer surface. Metallic components with a coating layer.

2. a metal member containing chromium; a coating layer that covers the metal member; Equipped with the coating layer has a second outer surface exposed to an oxidizing atmosphere and a first outer surface located away from the oxidizing atmosphere, and the coating layer is located so as to contact the first surface and the second surface of the metal member; The surface roughness of the first outer surface of the coating layer is greater than the surface roughness of the first surface and / or the second surface of the metal member. Metallic components with a coating layer.

3. The thickness of the coating layer where the second outer surface is located is greater in a portion facing a flow path of an oxygen-containing gas than in a portion located away from the flow path. The metal member with a coating layer according to claim 1 or 2.

4. The coating layer located between the second outer surface and the metal member has a higher porosity than the coating layer located between the first outer surface and the metal member. The metal member with a coating layer according to any one of claims 1 to 3.

5. a metal member containing chromium; a coating layer that covers the metal member; Equipped with At least one element of Mn, Ti, Ca, and Al is located at the interface between the metal member and the coating layer, and the content of Mn, Ti, Ca, and Al at the interface is greater than the content of Mn, Ti, Ca, and Al in the metal member or the coating layer. Metallic components with a coating layer.

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