Battery stack device, module, module receiving device and coated metal component

Abstract

A battery stack device comprises a plurality of battery cells, a metal component, a coating and a bonding member. The plurality of battery cells have an element portion and include a first battery cell. The metal component contains chromium. The coating covers the metal component. The bonding member is located between the first battery cell and the coating. The battery stack device satisfies any one of (1) to (3). (1) The coating has at least two parts at different positions, and the at least two parts have different thicknesses or different surface roughnesses. (2) The surface roughness of the coating is different from the surface roughness of the metal component. (3) At least one element of Mn, Ti, Ca and Al is arranged at the interface between the metal component and the coating, and the content of at least one of Mn, Ti, Ca and Al at the interface is different from the content of Mn, Ti, Ca and Al in the metal component or the coating.

Description

Technical Field

[0001] The invention relates to a battery stack device, a module, a module receiving device and a metal component with a coating. Background Art

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

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2015-162357 Summary of the invention

[0006] A battery stack device according to one embodiment of the present invention comprises a plurality of battery cells, a metal component, a coating, and a bonding member. The plurality of battery cells have an element portion and include a first battery cell. The metal component contains chromium. The coating covers the metal component. The bonding member is located between the first battery cell and the coating. The battery stack device satisfies any one of the following (1) to (3).

[0007] (1) The coating has at least two portions at different locations, and the at least two portions have different thicknesses or different surface roughnesses.

[0008] (2) The surface roughness of the coating layer is different from the surface roughness of the metal member.

[0009] (3) At least one element among Mn, Ti, Ca and Al is arranged at the interface between the metal component and the coating, and the content of at least one of Mn, Ti, Ca and Al at the interface is different from the content of Mn, Ti, Ca and Al in the metal component or the coating.

[0010] Furthermore, a module of the present invention includes the battery stack device described above and a storage container for storing the battery stack device.

[0011] Furthermore, a module housing device according to the present invention includes the above-described module, an auxiliary machine for operating the module, and an outer casing for housing the module and the auxiliary machine. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1A This is a cross-sectional view showing an example of a battery cell according to an embodiment.

[0013] Figure 1B This is a side view of an example of a battery cell according to an embodiment viewed from the air electrode side.

[0014] Figure 1C This is a side view of an example of the battery unit according to the embodiment as viewed from the embedded connector side.

[0015] Figure 2A This is a perspective view showing an example of a battery stack device according to an embodiment.

[0016] Figure 2B yes Figure 2A A cross-sectional view along line XX is shown.

[0017] Figure 2C This is a plan view showing an example of a battery stack device according to an embodiment.

[0018] Figure 3A yes Figure 2C A cross-sectional view taken along line YY is shown.

[0019] Figure 3B It is schematically shown Figure 3A An enlarged cross-sectional view of the main parts of the battery stack is shown.

[0020] Figure 4 yes Figure 2C A cross-sectional view taken along line ZZ is shown.

[0021] Figure 5A It is a perspective view showing another example of the metal member.

[0022] Figure 5B It is a perspective view showing another example of the metal member.

[0023] Figure 5C This is an enlarged cross-sectional view of a joint portion between another example of a metal member and a battery cell.

[0024] Fig. 6A This is an enlarged cross-sectional view of a joint portion between a metal member and a battery cell according to Modification 1 of the embodiment.

[0025] Figure 6B This is an enlarged cross-sectional view of a joint portion between a metal member and a battery cell according to Modification 2 of the embodiment.

[0026] Figure 6C This is an enlarged cross-sectional view of a joint portion between a metal member and a battery cell according to Modification 3 of the embodiment.

[0027] Fig.6D It is a cross-sectional view showing a metal member according to Modification 4 of the embodiment.

[0028] Fig. 6E It is a cross-sectional view showing a metal member according to a fifth modification of the embodiment.

[0029] Fig. 7A This is an enlarged cross-sectional view of a joint portion between another example of a metal member according to Modification 6 of the embodiment and a battery cell.

[0030] Figure 7B This is an enlarged cross-sectional view of a joint portion between another example of a metal member according to Modification 7 of the embodiment and a battery cell.

[0031] Fig. 8A It is a front view showing an end current collecting member according to Modification 8 of the embodiment.

[0032] Figure 8B It is a cross-sectional view showing an end current collecting member according to Modification 9 of the embodiment.

[0033] Figure 8C This is an enlarged cross-sectional view of a joint portion between an end current collecting member and a metal member according to Modification 10 of the embodiment.

[0034] Fig.8D This is an enlarged cross-sectional view of a joint portion between an end current collecting member and a metal member according to Modification 11 of the embodiment.

[0035] Fig. 9 This is an external perspective view showing an example of a module according to the embodiment.

[0036] Fig.10 It is an exploded perspective view schematically showing an example of the module housing device according to the embodiment.

[0037] Fig.11A It is a perspective view showing a flat-plate type battery cell according to Modification 12 of the embodiment.

[0038] Fig. 11B yes Fig.11A A partial cross-sectional view of a planar battery cell is shown.

[0039] Fig. 11C yes Fig. 11B An enlarged view of area A is shown. DETAILED DESCRIPTION

[0040] Hereinafter, embodiments of the battery stack device, module, and module storage device disclosed in the present application will be described in detail with reference to the accompanying drawings. It should be noted that the present invention is not limited to the embodiments described below.

[0041] In addition, the drawings are schematic, and it should be noted that the relationship between the dimensions of each element, the ratio of each element, etc. may be different from the actual situation. In addition, the relationship between the dimensions, the ratio, etc. may be different between the drawings.

[0042] <Battery Cell Structure>

[0043] First, refer to Figure 1A to Figure 1C , an example of using a solid oxide fuel cell as a battery cell constituting the battery stack device of the embodiment will be described.

[0044] Figure 1A is a cross-sectional view showing an example of a battery cell 1 according to an embodiment, Figure 1B This is a side view of an example of the battery cell 1 according to the embodiment as viewed from the air electrode 5 side. Figure 1C This is a side view of an example of the battery unit 1 according to the embodiment as viewed from the embedded connector 6 side. Figure 1A to Figure 1C Part of each structure of the battery cell 1 is shown in an enlarged manner.

[0045] exist Figure 1A to Figure 1C In the example shown, the battery cell 1 is a hollow flat plate type and has an elongated plate shape. Figure 1B As shown, the shape of the battery cell 1 as a whole when viewed from the side is, for example, a rectangle with a side length of 5 cm to 50 cm in the longitudinal direction L and a length of 1 cm to 10 cm in the width direction W perpendicular to the longitudinal direction L. The thickness of the battery cell 1 as a whole in the thickness direction T is, for example, 1 mm to 5 mm.

[0046] like Figure 1A As shown, the battery cell 1 includes a conductive support substrate 2, a device portion, and an embedded connector 6. The support substrate 2 is a columnar structure having a pair of opposing flat surfaces n1 and n2 and a pair of arc-shaped side surfaces m connecting the flat surfaces n1 and n2.

[0047] The element part is provided on the flat surface n1 of the support substrate 2. The element part includes a fuel electrode 3, a solid electrolyte layer 4, and an air electrode 5. Figure 1A In the example shown, the embedded connector 6 is provided on the flat surface n2 of the support substrate 2 .

[0048] In addition, if Figure 1B As shown in FIG. 1 , the air electrode 5 does not extend to the upper and lower ends of the battery cell 1. At the lower end of the battery cell 1, only the solid electrolyte layer 4 is exposed on the surface. Figure 1C As shown in FIG. 1 , the embedded connector 6 may also extend to the upper and lower ends of the battery cell 1. At the lower end of the battery cell 1, the embedded connector 6 and the solid electrolyte layer 4 are exposed on the surface. Figure 1A As shown, the solid electrolyte layer 4 is exposed on the surface of the pair of arc-shaped side surfaces m of the battery cell 1. The embedded connector 6 does not necessarily need to extend to the lower end of the battery cell 1.

[0049] Hereinafter, each component constituting the battery unit 1 will be described.

[0050] The support substrate 2 has a gas flow path 2 a inside thereof through which a gas flows. Figure 1A The example of the support substrate 2 shown has six gas flow paths 2a. The support substrate 2 has gas permeability and allows the fuel gas flowing in the gas flow paths 2a to pass through the fuel electrode 3. The support substrate 2 may also have conductivity. The conductive support substrate 2 collects electricity generated in the element portion to the embedded connector 6.

[0051] 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.

[0052] The material of the fuel electrode 3 can use a generally known material. The fuel electrode 3 can also use a porous conductive ceramic, such as a ceramic containing ZrO2 in which calcium oxide, magnesium oxide, or a rare earth element oxide is solid-dissolved, and Ni and / or NiO. As the rare earth element oxide, for example, Y2O3, Yb2O3, etc. are used. ZrO2 in which calcium oxide, magnesium oxide, or a rare earth element oxide is solid-dissolved is sometimes referred to as stabilized zirconia. Stabilized zirconia also includes partially stabilized zirconia.

[0053] The solid electrolyte layer 4 is an electrolyte and bridges ions between the fuel electrode 3 and the air electrode 5. The solid electrolyte layer 4 has a gas barrier property and makes it difficult for the fuel gas and the oxygen-containing gas to leak.

[0054] The material of the solid electrolyte layer 4 may be, for example, ZrO2 in which 3 mol% to 15 mol% of a rare earth element oxide is solid-dissolved. As the rare earth element oxide, for example, Y2O3, Yb2O3, etc. are used. It should be noted that other materials may be used as long as they have the above-mentioned properties.

[0055] The material of the air electrode 5 is not particularly limited as long as it is a material 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.

[0056] 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 a composite oxide include La x Sr 1-x Co y Fe 1-y O3, La x Sr 1_x MnO3、La x Sr1-x FeO3、La x Sr 1-x CoO3, etc. It should be noted that x is 0<x<1, and y is 0<y<1.

[0057] The air electrode 5 has air permeability. The open porosity of the air electrode 5 may be, for example, 20% or more, and particularly may be in the range of 30% to 50%.

[0058] The material of the embedded connector 6 may also be lanthanum chromate-based perovskite oxide (LaCrO3-based oxide), lanthanum-doped strontium titanate-based perovskite oxide (LaSrTiO3-based oxide), etc. These materials are conductive and will not be reduced or oxidized even when in contact with fuel gas such as hydrogen-containing gas and oxygen-containing gas such as air.

[0059] In addition, the embedded connector 6 is dense, which makes it difficult for the fuel gas flowing in the gas flow path 2a located inside the support substrate 2 and the oxygen-containing gas flowing outside the support substrate 2 to leak. The embedded connector 6 may have a relative density of 93% or more, and in particular, a relative density of 95% or more.

[0060] <Structure of battery stack device>

[0061] Next, refer to Figure 2A to Figure 2C A battery stack device 10 according to the present embodiment using the above-described battery cell 1 will be described. Figure 2A is a perspective view showing an example of a battery stack device 10 according to an embodiment. Figure 2B yes Figure 2A The cross-sectional view of line XX is shown. Figure 2C It is a plan view showing an example of the battery stack device 10 according to the embodiment.

[0062] like Figure 2A As shown in the figure, the battery stack device 10 includes: a battery stack 11 having a thickness direction T of the battery cell 1 (refer to Figure 1A ) are arranged (stacked) on a plurality of battery cells 1; and a fixing member 12. It should be noted that the battery stack 11 only needs to have one or more battery cells 1. In the case of having only one battery cell 1 as a first battery cell, it is also referred to as a battery stack 11 or a battery stack device 10 for convenience.

[0063] The fixing member 12 includes a joint 13 and a support member 14. The support member 14 supports the battery cell 1. The joint 13 joins the battery cell 1 and the support member 14. In addition, the support member 14 includes a support body 15 and a gas tank 16. The support body 15 and the gas tank 16 as the support member 14 are made of metal and have conductivity.

[0064] like Figure 2B As shown, the support body 15 has an insertion hole 15a into which the lower end portions of the plurality of battery cells 1 are inserted. The lower end portions of the plurality of battery cells 1 are joined to the inner wall of the insertion hole 15a by a joint member 13.

[0065] The gas tank 16 has an opening for supplying reaction gas to the plurality of battery cells 1 through the insertion hole 15a and a groove 16a around the opening. The outer peripheral end of the support body 15 is fixed to the gas tank 16 by a fixing member 21 filling the groove 16a of the gas tank 16.

[0066] exist Figure 2B In the example shown, fuel gas is stored in an internal space 22 formed by a support body 15 as a support member 14 and a gas tank 16. A gas flow pipe 20 is connected to the gas tank 16. The fuel gas is supplied to the gas tank 16 through the gas flow pipe 20, and flows from the gas tank 16 to a gas flow path 2a (see FIG. 2 ) inside the battery cell 1. Figure 1A The fuel gas supplied to the gas tank 16 is supplied by the reformer 102 (see Fig. 9 )generate.

[0067] The hydrogen-rich fuel gas can be produced by steam reforming a raw fuel, etc. When the fuel gas is produced by steam reforming, the fuel gas contains water vapor.

[0068] exist Figure 2A In the example shown, the battery stack 11 having a plurality of battery cells 1 includes two rows of battery stacks 11, two supports 15, and a gas tank 16. The two rows of battery stacks 11 each include a plurality of battery cells 1. Each battery stack 11 is fixed to each support 15. The gas tank 16 has two through holes on the upper surface. Each support 15 is disposed in each through hole. An internal space 22 is formed by one gas tank 16 and two supports 15.

[0069] The shape of the insertion hole 15a is, for example, an oblong shape when viewed from above. The length of the insertion hole 15a in the arrangement direction of the battery 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 battery stack 11. The width of the insertion hole 15a is, for example, greater than the width direction W of the battery cells 1 (see Figure 1A It should be noted that the shape of the insertion hole 15a may also be a substantially rectangular shape that is longer in the arrangement direction of the battery cells 1.

[0070] like Figure 2BAs shown, the joint portion where the inner wall of the insertion hole 15a is joined to the lower end of the battery cell 1 is filled and cured with the joint material 13. Thus, the inner wall of the insertion hole 15a is joined and fixed to the lower ends of the plurality of battery cells 1, respectively, and the lower ends of the battery cells 1 are joined and fixed to each other. The gas flow path 2a of each battery cell 1 is connected to the internal space 22 of the support member 14 at the lower end.

[0071] A material with low conductivity such as glass can be used for the bonding material 13 and the fixing material 21. As specific materials of the bonding material 13 and the fixing material 21, amorphous glass and the like can be used, and in particular, crystallized glass and the like can be used.

[0072] As crystallized glass, for example, any of the materials such as SiO2-CaO system, MgO-B2O3 system, La2O3-B2O3-MgO system, La2O3-B2O3-ZnO system, SiO2-CaO-ZnO system can be used, and in particular, SiO2-MgO system materials can also be used.

[0073] In addition, if Figure 2B As shown, a conductive member 18 is interposed between adjacent battery cells 1 among the plurality of battery cells 1. The conductive member 18 electrically connects the fuel electrode 3 of one adjacent battery cell 1 to the air electrode 5 of the other battery cell 1 in series. More specifically, the embedded connector 6 electrically connected to the fuel electrode 3 of one adjacent battery cell 1 is connected to the air electrode 5 of the other battery cell 1.

[0074] In addition, if Figure 2B As shown in FIG. 1 , the outermost battery cell 1 in the arrangement direction of the plurality of battery cells 1 is electrically connected to an end current collecting member 17. The end current collecting member 17 is connected to a conductive portion 19 protruding to the outside of the battery stack 11. The conductive portion 19 collects the electricity generated by the battery cell 1 and leads it to the outside. Figure 2A In the figure, the end current collecting member 17 is omitted.

[0075] In addition, if Figure 2C As shown, the battery stack device 10 has two battery stacks 11A and 11B connected in series, and functions as one battery. Therefore, the conductive portion 19 of the battery stack device 10 is divided into a positive terminal 19A, a negative terminal 19B, and a connection terminal 19C.

[0076] The positive terminal 19A is the positive electrode when the power generated by the battery stack 11 is output to the outside, and is electrically connected to the end current collecting member 17 on the positive electrode side of the battery stack 11A. The negative terminal 19B is the negative electrode when the power generated by the battery stack 11 is output to the outside, and is electrically connected to the end current collecting member 17 on the negative electrode side of the battery stack 11B.

[0077] The connection terminal 19C electrically connects the end current collecting member 17 on the negative electrode side in the battery stack 11A and the end current collecting member 17 on the positive electrode side in the battery stack 11B.

[0078] <Joining of Support Body and Battery Cell>

[0079] Next, refer to Figure 3A , Figure 3B The joining of the support body 15 and the battery cell 1 will be described. Figure 3A yes Figure 2C A cross-sectional view taken along line YY is shown. Figure 3B It is schematically shown Figure 3A An enlarged cross-sectional view of the main parts of the battery stack is shown. Figure 3B In FIG. 1 , the surface of the substrate 151 constituting the support body 15 is simplified and illustrated as a plane.

[0080] like Figure 3A , Figure 3B As shown, the support body 15 is joined to the battery cell 1 via a joining member 13 .

[0081] The support body 15 has a substrate 151 and a coating layer 152. The substrate 151 has electrical conductivity and heat resistance. The substrate 151 contains chromium. The substrate 151 is, for example, stainless steel. The substrate 151 is an example of a metal member. The substrate 151 may also contain, for example, a metal oxide.

[0082] The coating layer 152 covers the base material 151. The coating layer 152 is arranged so as to be in contact with the first surface 151a and the second surface 151b of the base material 151.

[0083] The coating 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.

[0084] The material of the coating 152 is, for example, an inorganic oxide. The inorganic oxide may be, for example, aluminum oxide (aluminum oxide), magnesium oxide (magnesium oxide), silicon oxide (silicon dioxide), zirconium oxide (zirconium oxide), chromium oxide (chromia), titanium oxide (titanium dioxide), and composite oxides thereof. Zirconium oxide may also be stabilized zirconium oxide. Composite oxides may be selected, for example, from forsterite and cordierite. The material of the coating 152 may be a material with low electrical conductivity or an insulating material. By making the material of the coating 152 a material with low electrical conductivity or an insulating material, the battery stack device 10 may have a high withstand voltage and a high insulation resistance.

[0085] In particular, the difference in thermal expansion coefficient between alumina and forsterite and the substrate 151 is small, and the thermal stress caused by the temperature difference is reduced. Therefore, the coating layer 152 can be firmly bonded to the substrate 151, and the coating layer 152 is unlikely to be peeled off from the substrate 151.

[0086] The coating layer 152 is located between the bonding member 13 and the base material 151 , thereby alleviating stress generated between the bonding member 13 and the base material 151 due to, for example, a difference in thermal expansion coefficient, and reducing the occurrence of cracks in the bonding member 13 .

[0087] The second surface 152b of the coating 152 where the bonding material 13 is not disposed is exposed to the external space 23. The external space 23 is a space where the air electrode 5 (see FIG. 1 ) of the battery cell 1 is exposed and is filled with oxygen-containing gas (air, etc.). That is, the external space 23 is an oxidizing atmosphere.

[0088] In addition, as described above, the substrate 151 contains chromium (Cr). For example, if the chromium (Cr) contained in the substrate 151 is released into the oxidizing atmosphere (external space 23), the performance of the air electrode 5 may be deteriorated.

[0089] Therefore, in the embodiment, the thickness of the coating layer 152 facing the oxidizing atmosphere (external space 23) can be increased. Figure 3B As shown, the thickness t2 of the coating layer 152 on the second surface 152 b is greater than the thickness t1 of the coating layer 152 on the first surface 152 a .

[0090] This makes it difficult for chromium contained in the substrate 151 to escape 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 thus the durability of the battery stack device 10 can be improved.

[0091] On the other hand, the coating 152 is bonded to the bonding material 13 , and there is a possibility that the fuel gas leaks from a gap generated between the support body 15 and the bonding material 13 due to the peeling of the coating 152 from the bonding material 13 depending on the operating environment, thereby reducing the durability of the battery stack device 10 .

[0092] Therefore, in the embodiment, the surface roughness of the coating layer 152 can be made greater than the surface roughness of the substrate 151. Specifically, for example, the surface roughness of the first surface 152a of the coating layer 152 can be made greater than the surface roughness of the first surface 151a of the substrate 151.

[0093] Thus, the adhesion between the coating 152 and the bonding member 13 can be improved. Therefore, for example, the support body 15 can be made difficult to be peeled off from the bonding member 13, and leakage of fuel gas is difficult to occur. Therefore, according to the embodiment, the durability of the support body 15 can be improved, and thus the durability of the battery stack device 10 can be improved.

[0094] It should be noted that the surface roughness of the second surface 152b of the coating 152 may be the same as or different from the surface roughness of the first surface 152a. In addition, the surface roughness of the second surface 151b of the substrate 151 may be the same as or different from the surface roughness of the first surface 151a.

[0095] In addition, in the embodiment, the bonding strength between the coating 152 and the substrate 151 can also be improved by adjusting the porosity of the coating 152. The thickness of the coating 152 located between the second surface 152b and the substrate 151 is greater than the thickness of the coating 152 located between the first surface 152a and the substrate 151, so that a greater stress is easily generated in the coating 152 located on the second surface 152b, and it is easier to peel off from the substrate 151 than the coating 152 located on the first surface 152a. Specifically, for example, the coating 152 located between the second surface 152b and the substrate 151 (the second surface 151b) can have a larger porosity than the coating 152 located between the first surface 152a and the substrate 151 (the first surface 151a).

[0096] Thus, stress relaxation in the coating 152 located on the second surface 152b can be improved, so the bonding strength between the coating 152 and the substrate 151 can be improved. Therefore, for example, the coating 152 can be made difficult to peel off from the substrate 151, so that the chromium contained in the substrate 151 is difficult to escape into the oxidizing atmosphere (external space 23). Therefore, according to the embodiment, the durability of the air electrode 5 can be improved, and thus the durability of the battery stack device 10 can be improved.

[0097] Furthermore, in an embodiment, the bonding strength between the coating 152 and the bonding member 13 can also be improved by adjusting the content of the metal element at the interface between the substrate 151 and the coating 152. Specifically, for example, at least one element of Mn, Ti, Ca and Al is configured on the first surface 151a and the second surface 151b corresponding to the interface between the substrate 151 and the coating 152. In addition, in the case where the coating 152 does not contain any of Mn, Ti, Ca and Al as the main component, the content of Mn, Ti, Ca and Al located on the first surface 151a and the second surface 151b can also be greater than the content of Mn, Ti, Ca and Al located on the substrate 151 and the coating 152. These metal elements can also diffuse mutually between the substrate 151 and the coating 152.

[0098] Thus, the adhesion between the substrate 151 and the coating 152 can be improved. Therefore, for example, it is possible to make it difficult for the substrate 151 and the coating 152 to peel off, thereby making it difficult for the fuel gas to leak. Therefore, according to the embodiment, the durability of the support body 15 can be improved, and thus the durability of the battery stack device 10 can be improved.

[0099] It should be noted that the above-mentioned metal element located at the interface between the substrate 151 and the coating 152 can be configured as a single substance, an alloy, a metal oxide or a composite oxide. In addition, the metal element can be located on either the substrate 151 side or the coating 152 side, or can be configured in a manner that straddles the substrate 151 and the coating 152.

[0100] In particular, Mn may be located in the convex portion of the substrate 151 or in the concave portion or pores of the coating 152. Ti may be located in the concave portion of the substrate 151 or in the pores of the coating 152. Ca may be located in the convex portion of the substrate 151 or in the concave portion or pores of the coating 152. Al may be located in the convex portion of the substrate 151 or in the concave portion or pores of the coating 152.

[0101] <Joining of Support Body and End Current Collecting Member>

[0102] Next, refer to Figure 4 The joining of the support body 15 and the end current collecting member 17 will be described. Figure 4 yes Figure 2C A cross-sectional view taken along line ZZ is shown.

[0103] like Figure 4 As shown, the end current collecting member 17 is joined to the support body 15 via the joining material 13 .

[0104] The end current collecting member 17 has a base material 171 and a cover 172. By covering the surface of the base material 171 with the cover 172, chromium (Cr) contained in the base material 171 is less likely to escape into the oxidizing atmosphere (external space 23) during high-temperature operation, thereby improving the durability of the end current collecting member 17.

[0105] The base material 171 is, for example, a conductive material containing chromium (Cr). The base material 171 may be, for example, stainless steel.

[0106] The material of the cover 172 may be, for example, an inorganic oxide. The cover 172 may also be a conductive oxide containing manganese (Mn) (eg, Mn 1.5 Co 1.5 O4, ZnMnCoO4, etc.). The covering member 172 can be located on the surface of the base material 171 by, for example, electrodeposition coating or the like.

[0107] The cover 172 covers the base material 171. The cover 172 is arranged to cover the surfaces 171a and 171b of the base material 171. The cover 172 has a surface 172a facing the bonding material 13 and a surface 172b exposed to the oxidizing atmosphere (external space 23).

[0108] The cover member 172 is located between the joining member 13 and the base material 171 , thereby alleviating stress generated between the joining member 13 and the base material 171 due to, for example, a difference in thermal expansion coefficient, and reducing the occurrence of cracks in the joining member 13 .

[0109] The base material 171 has a surface 171c adjacent to the surface 171a and facing the fastener 13. That is, one end (lower end) 172e of the cover member 172 faces the fastener 13, but does not face the internal space 22.

[0110] In the embodiment, the surface roughness of the cover 172 facing the bonding material 13 can be greater than the surface roughness of the cover 172 not facing the bonding material 13. Specifically, for example, the surface roughness of the surface 172a of the cover 172 can be greater than the surface roughness of the surface 172b.

[0111] Thus, the close contact between the cover 172 and the joint 13 can be improved. Therefore, for example, the end current collecting member 17 can be made difficult to be separated from the joint 13, thereby making it difficult for the fuel gas to leak. Therefore, according to the embodiment, the durability of the end current collecting member 17 can be improved, and thus the durability of the battery stack device 10 can be improved.

[0112] In the embodiment, the surface roughness of the base material 171 facing the bonding material 13 can be greater than the surface roughness of the cover material 172 facing the bonding material 13. Specifically, for example, the surface roughness of the surface 171c of the base material 171 can be greater than the surface roughness of the surface 172a.

[0113] Thus, the close contact between the end current collecting member 17 and the joint 13 can be improved. Therefore, for example, the end current collecting member 17 can be made difficult to be separated from the joint 13, thereby making it difficult for the fuel gas to leak. Therefore, according to the embodiment, the durability of the end current collecting member 17 can be improved, and thus the durability of the battery stack device 10 can be improved.

[0114] In addition, by making the surface roughness of the surface 172a smaller than the surface roughness of the surface 171c, it is possible to make it difficult for chromium contained in the base material 171 to escape into the oxidizing atmosphere (external space 23) through the cover 172 during high-temperature operation, for example. Therefore, according to the embodiment, the durability of the end current collecting member 17 can be improved, and thus the durability of the battery stack device 10 can be improved.

[0115] Furthermore, in the embodiment, the area of ​​the surface 171 c may be smaller than the area of ​​the surface 172 a. Specifically, for example, the area S2 of the surface 171 c may be smaller than the area S1 of the surface 172 a.

[0116] Thus, for example, during high-temperature operation, chromium contained in the base material 171 can be prevented from escaping to the oxidizing atmosphere (external space 23) via the cover 172, and leakage of fuel gas can be prevented from occurring by preventing the end current collecting member 17 from being peeled off from the joint 13. Therefore, according to the embodiment, the durability of the end current collecting member 17 can be improved, and thus the durability of the battery stack device 10 can be improved.

[0117] It should be noted that the surface roughness of the surface 171b of the base material 171 can be smaller than the surface roughness of the surface 171a. For example, if the surface roughness of the surface 171b is smaller than the surface roughness of the surface 171a, it is possible to make it difficult for the chromium contained in the base material 171 to escape into the oxidizing atmosphere (external space 23) through the surface 172b of the cover 172 during high-temperature operation. It should be noted that the surface roughness of the surfaces 171a and 171b can also be the same.

[0118] Furthermore, the base material 171 may include an oxide layer 173 disposed so as to face the cover material 172 and the bonding material 13. The oxide layer 173 may be, for example, a natural oxide film composed of chromium oxide (Cr2O3).

[0119] The constituent elements of the oxide layer 173 hardly undergo a reduction reaction, for example, in a reducing atmosphere. 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 separate from the surface exposed in the reducing atmosphere (internal space 22). Therefore, according to the embodiment, the durability of the end current collecting member 17 can be improved, and thus the durability of the battery stack device 10 can be improved.

[0120] On the other hand, the support body 15 is as Figure 2C As shown in FIG. 1 , the support body 15 is arranged so as to surround the periphery of the bonding member 13 filling the oblong insertion hole 15a in a plan view. The insertion hole 15a of the support body 15 has a first direction along the arrangement direction of the battery cells 1, that is, the thickness direction T (see FIG. 1 ). Figure 1A ) is a straight portion (first portion 15A) extending straightly and a curved portion (second portion 15B) curved in a first direction. The battery cell 1 is arranged opposite to the first portion 15A of the support body 15, and the end current collecting member 17 is arranged opposite to the second portion 15B of the support body 15.

[0121] In an embodiment, the thickness of the coating 152 located in the second portion 15B of the support body 15 may be greater than the thickness of the coating 152 located in the first portion 15A. Specifically, the thickness t1 of the coating 152 located on the first surface 152a (see Figure 3B ), the second portion 15B is larger than the first portion 15A.

[0122] In the second portion 15B of the support body 15 that is curved in a plan view, stress caused by the difference in thermal expansion of each member is easily concentrated compared to the first portion 15A. In this way, by making the thickness of the coating 152 where the first surface 152a is located different according to the plan view shape of the support body 15, especially the insertion hole 15a, for example, it is possible to alleviate the concentration of stress in the second portion 15B. Therefore, according to the embodiment, the durability of the support body 15 can be improved, and thus the durability of the battery stack device 10 can be improved.

[0123] In addition, in the embodiment, the inner surface 151e is described as being exposed in the reducing atmosphere (internal space 22), but the present invention is not limited to this. For example, a coating layer arranged so as to cover the inner surface 151e may be provided.

[0124] <Various Modifications>

[0125] Next, refer to Figure 5A to Figure 7B The support body 15 according to various modified examples of the embodiment will be described. Figure 5A , Figure 5B It is a perspective view showing another example of the metal member.

[0126] In use Figure 5A In the case of a flat plate-shaped support body 15 as shown, for example, by placing a gas tank 16 (see Figure 2A ) is joined to the lower surface or side surface of the flat support 15 to form an internal space 22 (refer to Figure 2B ).in addition, Figure 5B The support body 15 shown has a plurality of insertion holes 15 a. In this case, one battery cell 1 may be inserted into each of the plurality of insertion holes 15 a of the support body 15, or a plurality of battery cells 1 may be inserted into each of the plurality of insertion holes 15 a of the support body 15.

[0127] Figure 5C FIG. 2 is an enlarged cross-sectional view of a joint portion where another example of a metal member is joined to a battery cell. Figure 5C As shown, the support body 15 has a flat plate shape and is joined to the battery cell 1 via a joining member 13 .

[0128] 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).

[0129] The coating 152 covers the substrate 151. The coating 152 is located between the first surface 151a of the substrate 151 and the bonding member 13. In addition, the coating 152 is located between the second surface 151b of the substrate 151 and the oxidizing atmosphere (external space 23). The coating 152 has a first surface 152a and a second surface 152b. The first surface 152a faces the bonding member 13. The second surface 152b faces the oxidizing atmosphere (external space 23).

[0130] The bonding member 13 bonds the battery cell 1 to the support 15. The bonding member 13 is located on the solid electrolyte layer 4 (see Figure 1A ) between the coating layer 152 of the support body 15, and the battery cell 1 is bonded to the first surface 152a of the coating layer 152 which is the first outer surface.

[0131] In the support body 15 of the embodiment, the thickness t2 of the coating layer 152 on the second surface 152b of the coating layer 152 exposed in the oxidizing atmosphere (external space 23) is greater than the thickness t1 of the coating layer 152 on the first surface 152a facing the bonding material 13.

[0132] This makes it difficult for chromium contained in the substrate 151 to escape 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 thus the durability of the battery stack device 10 can be improved.

[0133] On the other hand, the coating 152 is bonded to the bonding material 13 , and there is a possibility that fuel gas leakage may occur from a gap generated between the support body 15 and the bonding material 13 due to peeling of the coating 152 from the bonding material 13 depending on the operating environment, thereby reducing the durability of the battery stack device 10 .

[0134] Therefore, in the embodiment, the surface roughness of the coating layer 152 can be greater than that of the substrate 151. Specifically, for example, the surface roughness of the first surface 152a of the coating layer 152 can be greater than that of the first surface 151a and the second surface 151b of the substrate 151.

[0135] Thus, the adhesion between the coating 152 and the joint 13 can be improved. Therefore, for example, it is possible to make it difficult for the support body 15 to be peeled off from the joint 13, thereby making it difficult for the fuel gas to leak. Therefore, according to the embodiment, the durability of the support body 15 can be improved, and thus the durability of the battery stack device 10 can be improved.

[0136] It should be noted that the surface roughness of the second surface 151b of the substrate 151 may be the same as or different from the surface roughness of the first surface 151a. In addition, the surface roughness of the second surface 152b of the coating 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. Thus, for example, during high-temperature operation, it is difficult for the chromium (Cr) contained in the substrate 151 to escape into the oxidizing atmosphere (external space 23) through the second surface 152b of the coating 152. Therefore, the durability of the support body 15 can be improved, and thus the durability of the battery stack device 10 can be improved.

[0137] In addition, in the embodiment, the bonding strength between the coating 152 and the bonding member 13 can be improved by adjusting the porosity of the coating 152. Specifically, for example, the coating 152 located between the second surface 152b and the second surface 151b of the substrate 151 can have a larger porosity than the coating 152 located between the first surface 152a and the first surface 151a of the substrate 151.

[0138] Thus, stress relaxation in the coating layer 152 located on the second surface 152b can be improved, and thus the bonding strength between the coating layer 152 and the bonding member 13 can be improved. Therefore, it is possible to make it difficult for the support body 15 to be peeled off from the bonding member 13, and thus it is difficult for the fuel gas to leak. Therefore, according to the embodiment, the durability of the support body 15 can be improved, and thus the durability of the battery stack device 10 can be improved.

[0139] Furthermore, in the embodiment, the bonding strength between the coating 152 and the bonding member 13 can also be improved by adjusting the content of the metal element at the interface between the substrate 151 and the coating 152. Specifically, for example, at least one element of Mn, Ti, Ca, and Al is configured on the first surface 151a and the second surface 151b corresponding to the interface between the substrate 151 and the coating 152. In addition, the content of Mn, Ti, Ca, and Al at the first surface 151a and the second surface 151b may be greater than the content of Mn, Ti, Ca, and Al at the substrate 151 and the coating 152.

[0140] Thus, the adhesion between the substrate 151 and the coating 152 can be improved. Therefore, for example, it is possible to make it difficult for the substrate 151 and the coating 152 to peel off, thereby making it difficult for the fuel gas to leak. Therefore, according to the embodiment, the durability of the support body 15 can be improved, and thus the durability of the battery stack device 10 can be improved.

[0141] It should be noted that the above-mentioned metal element located at the interface between the substrate 151 and the coating 152 can be configured as a single body, an alloy or a metal oxide. In addition, the metal element can be located on either the substrate 151 side or the coating 152 side, or can be configured in a manner that straddles the substrate 151 and the coating 152.

[0142] in addition, Figure 5B The insertion hole 15a of the support body 15 shown in the figure has a first portion 15A extending in the width direction W of the battery cell 1 (see Figure 1A ) extends; a second portion 15B, which is bent from the first direction; and a third portion 15C, which is arranged along the direction of the battery cell 1, that is, the thickness direction T (reference Figure 1A )extend.

[0143] In the embodiment, the thickness of the coating 152 located in the second portion 15B of the support body 15 may be greater than the thickness of the coating 152 located in the first portion 15A and the third portion 15C. Figure 5C ), the second portion 15B is larger than the first portion 15A and the third portion 15C.

[0144] In the second portion 15B of the support body 15 that is curved in a plan view, stress caused by the difference in thermal expansion of each member is easily concentrated compared to the first portion 15A and the third portion 15C. In this way, by making the thickness of the coating 152 where the first surface 152a is located different according to the plan view shape of the support body 15, especially the insertion hole 15a, for example, the concentration of stress in the second portion 15B can be alleviated. Therefore, according to the embodiment, the durability of the support body 15 can be improved, and thus the durability of the battery stack device 10 can be improved.

[0145] Figure 6A to Figure 6E This is an enlarged cross-sectional view of a joint portion between a metal member and a battery cell according to Modifications 1 to 5 of the embodiment. Fig. 7A , Figure 7B This is an enlarged cross-sectional view of a joint portion between another example of a metal member and a battery cell according to Modifications 6 and 7 of the embodiment.

[0146] like Fig. 6A , Fig. 7A As shown, the coating 152 of the support body 15 may also further include an intermediate surface 152c located between the first surface 152a and the second surface 152b.

[0147] The intermediate surface 152c faces the joining member 13. The intermediate surface 152c may also have a smaller surface roughness than the first surface 152a, for example. The intermediate surface 152c is located at a position closer to the oxidizing atmosphere than the first surface 152a. By making the surface roughness of the intermediate surface 152c in the coating 152 facing the joining member 13 smaller than the first surface 152a located at a position away from the oxidizing atmosphere, it is possible to make it difficult for the chromium (Cr) contained in the substrate 151 to escape to the oxidizing atmosphere (external space 23) through the coating 152 during high-temperature operation, for example. Therefore, according to the embodiment, the durability of the support body 15 can be improved, and thus the durability of the battery stack device 10 can be improved. It should be noted that the surface roughness of the coating 152 located at the intermediate surface 152c may also be the same as the surface roughness of the second surface 152b, for example. In addition, the intermediate surface 152c may also have a surface roughness between the first surface 152a and the second surface 152b, for example.

[0148] In addition, the coating 152 where the intermediate surface 152c is located may, for example, be thicker than the coating 152 where the first surface 152a is located. The intermediate surface 152c is located at a position closer to the oxidizing atmosphere than the first surface 152a. By making the thickness of the intermediate surface 152c in the coating 152 facing the joint 13 larger than that of the first surface 152a located at a position away from the oxidizing atmosphere, it is possible to make it difficult for the chromium (Cr) contained in the substrate 151 to escape into the oxidizing atmosphere (external space 23) through the coating 152 during high-temperature operation, for example. Therefore, according to the embodiment, the durability of the support body 15 can be improved, and thus the durability of the battery stack device 10 can be improved. It should be noted that the thickness of the coating 152 located at the intermediate surface 152c may, for example, be the same as the thickness t2 of the second surface 152b (refer to Figure 3B ) are the same. In addition, the intermediate surface 152c may have a thickness intermediate between the thicknesses t1 and t2, for example.

[0149] On the other hand, Figure 6B , Figure 7B As shown, the coating 152 of the support body 15 may also further include an intermediate surface 152d located between the first surface 152a and the second surface 152b.

[0150] The intermediate surface 152d is exposed to the oxidizing atmosphere (external space 23). The intermediate surface 152d has a larger surface roughness than the second surface 152b, for example. In this way, in the case of having the intermediate surface 152d, for example, it is possible to make it difficult for the chromium (Cr) contained in the substrate 151 to escape into the oxidizing atmosphere (external space 23) during high-temperature operation. Therefore, according to the embodiment, the durability of the support body 15 can be improved, and thus the durability of the battery stack device 10 can be improved. It should be noted that the surface roughness of the intermediate surface 152d can be, for example, the same as the surface roughness of the first surface 152a. In addition, the intermediate surface 152d can also have a surface roughness intermediate between the first surface 152a and the second surface 152b.

[0151] In addition, Fig. 6A , Figure 6B , Fig. 7A , Figure 7B In each of the modified examples shown, an example is 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.

[0152] In addition, if Figure 6C As shown, the second surface 152 b of the coating layer 152 exposed to the oxidizing atmosphere (external space 23 ) may include surfaces 152 b 1 and 152 b 2 having different thicknesses of the coating layer 152 .

[0153] The surface 152b2 is located farther from the element portion of the battery cell 1 than the surface 152b1. The surface 152b1 near the element portion is more likely to become high temperature than the surface 152b2 far from the element portion, and the chromium (Cr) contained in the substrate 151 is more likely to escape into the oxidizing atmosphere (external space 23). Therefore, the thickness of the coating 152 where the surface 152b1 is located can be made larger than the thickness of the coating 152 where the surface 152b2 far from the element portion is located.

[0154] By making the thickness of the coating 152 where the surface 152b1 is located greater than the thickness of the coating 152 where the surface 152b2 is located, it is possible to make it difficult for chromium (Cr) contained in the substrate 151 to escape into the oxidizing atmosphere (external space 23) during high-temperature operation, for example. Therefore, according to the embodiment, the durability of the support body 15 can be improved, and thus the durability of the battery stack device 10 can be improved.

[0155] In addition, the surface roughness of the surface 152b1 close to the element portion can be made greater than the surface roughness of the surface 152b2 away from the element portion. By increasing the surface roughness of the surface 152b1, the flow of the oxygen-containing gas (air) located near the element portion can be changed to extend 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, so the reaction efficiency of the battery stack device 10 can be improved.

[0156] It should be noted that in Figure 6C In the example shown, the boundary between the surfaces 152b1 and 152b2 is located at the upper end of the support body 15, but the present invention is not limited to this. Figure 2C As shown in the figure, the upper surface that can be visually confirmed when looking down at the battery stack device 10 is set as surface 152b1, and the side surface located on the side of surface 152b1 is set as surface 152b2. In addition, the part that reaches a temperature above a specified value during high-temperature operation can be set as surface 152b1, and the other part can be called surface 152b2. In addition, the part facing the flow path (not shown) of the oxygen-containing gas (air) can be set as surface 152b1, and the other part can be set as surface 152b2.

[0157] In addition, if Fig.6D As shown in the figure, the coating 152 of the support body 15 may also 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 coating 152. In this way, the coating 152 has the connecting surface 152f, so that the durability of the support body 15 can be improved, and thus the durability of the battery stack device 10 can be improved.

[0158] It should be noted that the connection surface 152f may also face the bonding member 13 together with the first surface 152a. In addition, the connection surface 152f may also be exposed in the oxidizing atmosphere (external space 23) together with the second surface 152b. Furthermore, the connection surface 152f may also have a portion facing the bonding member 13 and a portion exposed in the oxidizing atmosphere (external space 23).

[0159] In addition, if Fig. 6E As shown in FIG. 1 , the thickness of the coating layer 152 may be constant. In this 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 improved, and thus the durability of the battery stack device 10 can be improved. In addition, 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 different as described above, the durability of the support body 15 can be improved, and thus the durability of the battery stack device 10 can be improved.

[0160] In addition, if Fig. 6EAs shown in FIG. 1 , the surface 152g located between the first surface 152a and the second surface 152b may also have a surface roughness intermediate between the first surface 152a and the second surface 152b. In addition, the porosity in the portion P3 of the coating 152 where the surface 152g is located may also have a porosity intermediate between the portions P1 and P2. In this way, by configuring the surface 152g, the durability of the support body 15 can be improved, and thus the durability of the battery stack device 10 can be improved.

[0161] Fig. 8A It is a front view showing an end current collecting member according to Modification 8 of the embodiment. Figure 8B It is a cross-sectional view showing an end current collecting member according to Modification 9 of the embodiment.

[0162] like Fig. 8A As shown, the upper end 17a of the end current collecting member 17 which can be visually recognized when viewed from the upper surface may be chamfered at the corner 17a1.

[0163] In addition, if Figure 8B As shown, the lower end 17b of the end current collecting member 17 has an end surface 17f inclined with respect to the direction in which the battery cells 1 are arranged so that the width of the end 17e is smaller than the thickness of the end current collecting member 17. Therefore, the end current collecting member 17 can be smoothly inserted into the bonding material 13 before curing.

[0164] Figure 8C , Fig.8D This is an enlarged cross-sectional view of a joint portion between an end current collecting member and a metal member according to Modifications 10 and 11 of the embodiment.

[0165] like Figure 8C As shown, the cover 172 may have a surface 172f located at one end (lower end) 172e of the cover 172 of the end current collecting member 17 and connecting the surface 171a (surface 171c) of the base material 171 and the surface 172a of the cover 172.

[0166] In addition, if Fig.8D As shown, the cover 172 may include a protrusion 172 g located on one end (lower end) 172 e side of the cover 172 of the end current collecting member 17 and protruding in a direction away from the surface 172 a and facing the joining member 13 .

[0167] Thus, the contact area between the cover 172 and the joint 13 is increased by the cover 172 having the surface 172f or the protrusion 172g. This can improve the durability of the end current collecting member 17, and thus improve the durability of the battery stack device 10. Figure 8C as well as Fig.8DIn the figure, the cover 172 is shown to have the surface 172f or the protrusion 172g, but the cover 172 may have the surface 172f and the protrusion 172g.

[0168] <Evaluation method>

[0169] Here, the thickness of each surface of the above-mentioned support body 15 and the end current collecting member 17 and each surface described later is calculated by image analysis of a cross section perpendicular to each surface. First, the support body 15 and the joint member 13, or the end current collecting member 17 and the joint member 13 are cut out and embedded in resin, and the cross section perpendicular to the surface for measuring the surface roughness is polished using abrasive grains, polishing paper (#8000 degree), etc. to obtain a cross section in a mirror state. The obtained cross section is photographed using a SEM (scanning electron microscope), an optical microscope, etc., and the obtained image is analyzed, so that the thickness of each surface can be measured separately.

[0170] The surface roughness of each surface of the support 15 and the end current collecting member 17 and each surface described later 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, similarly to the thickness of each surface.

[0171] The porosity in each portion of the coating 152 can be calculated as the ratio of the total area of ​​pores to the area of ​​the entire image by, for example, analyzing an image obtained by observing a cross section of each portion of the coating 152 using a SEM (scanning electron microscope).

[0172] In addition, the content of Mn, Ti, Ca and Al in each part of the support body 15 can be confirmed by, for example, cutting or scraping each part of the support body 15 from the battery cell 1 and performing elemental analysis such as ICP emission spectrometry. In addition, it can be calculated by performing elemental analysis on the cross section of the support body 15 using an electron probe microanalyzer (EPMA), a wavelength dispersive X-ray spectrometer (WDS) or an energy dispersive X-ray spectrometer (EDS).

[0173] (Thickness of coating)

[0174] The thickness of the coating layer 152 calculated as described above can be set to, for example, 2 μm to 400 μm on average over the entire support body 15 .

[0175] (Surface roughness of each surface)

[0176] 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 surface roughness (arithmetic mean roughness Ra) of each surface described later may be the same as that of the above-mentioned surfaces.

[0177] (Porosity of coating)

[0178] The porosity of the coating layer 152 and the coating layer described later calculated as described above can be set to, for example, 10% by area to 40% by area on average over the entire support body 15 .

[0179] It should be noted that the coating 152 may have a crack with an opening width of 10 μm or less, for example. In addition, the joint 13 may be arranged inside the crack. By arranging the joint 13 inside the crack, for example, the durability of the support body 15 can be improved, and thus the durability of the battery stack device 10 can be improved.

[0180] (Contents of Mn, Ti, Ca and Al)

[0181] The content of Mn, Ti, Ca and Al in the support body 15 and the support member described later calculated as described above can be set to, for example, 0.01% by mass to 10% by mass on average for the entire support body 15. In addition, the content of Mn, Ti, Ca and Al in the interface between the substrate 151 and the coating 152, the substrate 151 and the coating 152 can be set to, for example, 0.1% by mass to 30% by mass (interface), 0.01% by mass to 10% by mass (substrate 151), and 0.01% by mass to 10% by mass (coating 152), respectively.

[0182] (Preparation method)

[0183] The coating layer 152 of the embodiment can be disposed by, for example, spraying, vapor deposition, electrodeposition, sputtering, etc. Alternatively, for example, the coating layer 152 may be formed by coating the surface of the substrate 151 with a covering material and then firing it.

[0184] In addition, the first surface 152a and the second surface 152b of the coating 152 can be formed based on the difference in surface roughness of the first surface 151a and the second surface 151b of the substrate 151 corresponding to the first surface 152a and the second surface 152b, for example. In addition, it can also be formed by making the thickness of the portion corresponding to the second surface 152b larger than the thickness of the portion corresponding to the first surface 152a. In addition, for example, the second surface 152b can be formed by grinding the portion corresponding to the second surface 152b on the surface of the coating 152, and the remaining portion is set as the first surface 152a. In addition, the first surface 152a and the second surface 152b can also be formed respectively by changing various conditions when the above-mentioned coating 152 is formed. In addition, with respect to other surfaces, the manufacturing methods of the above-mentioned first surface 152a and the second surface 152b and known methods can also be appropriately combined to form.

[0185] <Module>

[0186] Next, use Fig. 9 A module 100 according to an embodiment of the present invention using the above-described battery stack device 10 will be described. Fig. 9 It is a perspective view showing the appearance of the module according to the embodiment, and shows a state in which the front surface and the rear surface as a part of the storage container 101 are removed and the cell stack device 10 of the fuel cell stored inside is taken out to the rear.

[0187] like Fig. 9 As shown, the module 100 includes a storage container 101 and a battery stack device 10 stored in the storage container 101. In addition, a reformer 102 is arranged above the battery stack device 10.

[0188] The reformer 102 reforms a raw fuel such as natural gas or kerosene to generate a fuel gas, and supplies it to the battery cell 1. The raw fuel is supplied to the reformer 102 through a raw fuel supply pipe 103. It should be noted that the reformer 102 may also include a gasification unit 102a and a reforming unit 102b for vaporizing water. 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 as a reforming reaction with a relatively high efficiency.

[0189] Then, the fuel gas generated by the reformer 102 is discharged into the gas flow path 2a (see FIG. 1 ) of the battery cell 1 through the gas flow pipe 20, the gas tank 16, and the support member 14. Figure 1A )supply.

[0190] In the module 100 having the above-described structure, the temperature inside the module 100 during power generation usually reaches about 500° C. to 1000° C. as the gas is combusted and the battery cells 1 generate power.

[0191] In such a module 100 , as described above, the battery stack device 10 that reduces the reduction in battery performance is accommodated and configured, so that the module 100 that reduces the reduction in battery performance can be achieved.

[0192] <Module Storage Device>

[0193] Fig.10 1 is an exploded perspective view showing an example of a module storage device according to an embodiment. The module storage device 110 according to the embodiment includes an outer casing 111, Fig. 9 The module 100 shown in the figure and the auxiliary machine not shown in the figure. The auxiliary machine operates the module 100. The module 100 and the auxiliary machine are accommodated in the outer casing 111. It should be noted that Fig.10 In the figure, part of the structure is omitted.

[0194] Fig.10 The outer casing 111 of the module housing device 110 shown in the figure has pillars 112 and an outer panel 113. The partition plate 114 divides the outer casing 111 into upper and lower parts. The space above the partition plate 114 in the outer casing 111 is a module housing chamber 115 for housing the module 100, and the space below the partition plate 114 in the outer casing 111 is an auxiliary machine housing chamber 116 for housing auxiliary machines for operating the module 100. It should be noted that Fig.10 In FIG. 1 , the auxiliary machines accommodated in the auxiliary machine accommodation chamber 116 are omitted and shown.

[0195] The partition plate 114 has an air flow port 117 for allowing air in the auxiliary machine accommodation chamber 116 to flow toward the module accommodation chamber 115. The exterior plate 113 constituting the module accommodation chamber 115 has an exhaust port 118 for exhausting air in the module accommodation chamber 115.

[0196] In such a module housing device 110 , as described above, by providing the module 100 that reduces the degradation of battery performance in the module housing chamber 115 , it is possible to achieve the module housing device 110 that reduces the degradation of battery performance.

[0197] <Other Modifications>

[0198] Next, refer to Figures 11A to 11C A battery stack device according to another modified example of the embodiment will be described.

[0199] In the above-mentioned embodiment, a so-called "vertical stripe type" is exemplified in which only one element portion including a fuel electrode, a solid electrolyte layer and an air electrode is provided on the surface of a supporting substrate, but it can be applied to a so-called "horizontal stripe type" battery stack device in which element portions are respectively provided at a plurality of mutually separated portions on the surface of a supporting substrate and adjacent element portions are electrically connected.

[0200] In addition, in the present embodiment, the case of using a hollow flat support substrate is exemplified, but it can also be applied to a battery stack device using a cylindrical support substrate. In addition, as described later, it can also be applied to a flat battery stack device in which so-called "flat" battery cells are stacked in the thickness direction.

[0201] In addition, in the above embodiment, an example is shown in which a fuel electrode is provided on a supporting substrate and an air electrode is arranged on the surface of a battery cell, but it can also be applied to a battery stack device with the opposite configuration, that is, an air electrode is provided on a supporting substrate and a fuel electrode is arranged on the surface of a battery cell.

[0202] In addition, in the above-mentioned embodiment, a fuel cell unit, a fuel cell stack device, a fuel cell module, and a fuel cell device are shown as an example of a "battery unit", a "battery stack device", a "module", and a "module housing device", but as another example, they may be an electrolysis cell unit, an electrolysis cell stack device, an electrolysis module, and an electrolysis device, respectively.

[0203] Fig.11A It is a perspective view showing a flat-plate type battery cell according to Modification 12 of the embodiment. Fig. 11B yes Fig.11A A partial cross-sectional view of a planar battery cell is shown. Fig. 11C yes Fig. 11B An enlarged view of area A is shown.

[0204] like Fig.11A As shown in FIG. 1 , the battery stack device includes a battery cell 1A in which a fuel electrode 3, a solid electrolyte layer 4, and an air electrode 5 are stacked. Fig. 11B As shown in the figure, the battery cell 1A has an element portion 90 in which the solid electrolyte layer 4 is sandwiched by the fuel electrode 3 and the air electrode 5. In a battery stack device in which a plurality of flat-plate-type battery cells are stacked, for example, the element portions 90 of the plurality of battery cells 1A are electrically connected by conductive members 91 and 92, which are adjacent metal layers. The conductive members 91 and 92 electrically connect the element portions 90 of the adjacent battery cells 1A to each other, and have a gas flow path for supplying gas to the fuel electrode 3 or the air electrode 5.

[0205] like Fig. 11B As shown, the flat-plate type battery stack has a seal that hermetically seals the fuel gas flow path 98 and the oxygen-containing gas flow path 97. The seal is a fixing member 96 of the battery cell, and has a joint 93 and supporting members 94 and 95 as a frame. The joint 93 can be glass or a metal material such as silver solder.

[0206] The support member 94 may also be a so-called diaphragm that divides the flow path 98 of the fuel gas and the flow path 97 of the oxygen-containing gas. The material of the support members 94 and 95 may be, for example, a conductive metal or an insulating ceramic. When the bonding member 93 is insulating, such as glass, the support members 94 and 95 may be made of metal on both sides or an insulating material on either side. When the bonding member 93 is a conductive metal, the support members 94 and 95 may be made of insulating materials on both sides or on either side. When the support members 94 and 95 are metal, the support members 94 and 95 may also be integrated with the conductive member 92.

[0207] The joint 93 and any of the supporting members 94 and 95 are insulating, and electrically insulate the two conductive members 91 and 92 sandwiching the flat battery cell from each other.

[0208] The flat battery cell of this modification example is as follows Fig. 11C As shown in the figure, it is provided with a support member 94 and a bonding member 93. The support member 94 has a substrate 941 and a coating 942. The substrate 941 has a first surface 941a and a second surface 941b, and contains chromium. The coating 942 covers the first surface 941a and the second surface 941b of the substrate 941. The bonding member 93 is located between the solid electrolyte layer 4 of the element part 90 and the first surface 942a of the coating 942.

[0209] Furthermore, the second surface 942b of the coating 942 is exposed in the oxidizing atmosphere (flow path 97). The thickness of the coating 942 where the second surface 942b is located is greater than the thickness of the coating 942 where the first surface 942a is located. Thus, it is possible to make it difficult for chromium (Cr) contained in the substrate 941 to escape 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 thus the durability of the battery stack device can be improved.

[0210] In addition, the surface roughness of the first surface 942a can also be greater than the surface roughness of the second surface 942b. Thus, it is possible to make the joint 93 difficult to peel off from the coating 942, or it is possible to make the joint 93 difficult to break and difficult to produce leakage of fuel gas. Therefore, according to the embodiment, the durability of the support member 94 can be improved.

[0211] Furthermore, the porosity of the coating 942 where the second surface 942b is located may be greater than the porosity of the coating 942 where the first surface 942a is located. Thus, it is possible to make it difficult for chromium (Cr) contained in the substrate 941 to escape into the oxidizing atmosphere (flow path 97) via the coating 942 during high-temperature operation. Therefore, according to the embodiment, the durability of the support member 94 can be improved, and thus the durability of the battery stack device can be improved.

[0212] It should be noted that in Fig. 11CIn the example shown, the coating layer 942 is arranged to cover the surface 941e of the substrate 941 facing the reducing atmosphere (flow path 98), but the present invention is not limited thereto, and the surface 941e may be exposed to the reducing atmosphere (flow path 98).

[0213] As mentioned above, although this invention was demonstrated in detail, this invention is not limited to the said embodiment, Various changes, improvements, etc. can be made within the range which does not deviate from the summary of this invention.

[0214] As described above, the battery stack device 10 of the embodiment includes a plurality of battery cells 1, a metal member (substrate 151), a coating 152, and a bonding member 13. The plurality of battery cells 1 have an element portion and include a first battery cell. The metal member (substrate 151) contains chromium. The coating 152 covers the metal member (substrate 151). The bonding member 13 is located between the first battery cell and the coating 152. The battery stack device 10 satisfies any one of (1) to (3). (1) The coating 152 has at least two portions at different positions, and the at least two portions have different thicknesses or different surface roughnesses. (2) The surface roughness of the coating 152 is different from the surface roughness of the metal member. (3) At least one element of Mn, Ti, Ca, and Al is arranged at the interface between the metal member and the coating, and the content of at least one of Mn, Ti, Ca, and Al at the interface is different from the content of Mn, Ti, Ca, and Al of the metal member or the coating. Thus, the durability of the battery stack device 10 can be improved.

[0215] Furthermore, the module 100 of the embodiment includes the battery stack device 10 described above and the storage container 101 that stores the battery stack device 10. Thus, the module 100 can reduce the degradation of battery performance.

[0216] The module housing device 110 of the embodiment includes the module 100 described above, auxiliary equipment for operating the module 100, and an outer casing housing the module 100 and the auxiliary equipment. Thus, the module housing device 110 can reduce the degradation of battery performance.

[0217] The embodiments disclosed this time are illustrative in all aspects and should not be considered as restrictive. In fact, the above-mentioned embodiments can be embodied in various ways. In addition, the above-mentioned embodiments can also be omitted, replaced, and changed in various ways without departing from the technical solution and its purpose.

[0218] Description of Reference Numerals

[0219] 1 Battery Cell

[0220] 10 Battery stack device

[0221] 11 Battery stack

[0222] 12 Fixed components

[0223] 13 Joints

[0224] 14 Supporting member

[0225] 15 Support

[0226] 16 Gas Tanks

[0227] 17 End current collecting member

[0228] 18 Conductive components

[0229] 23 External Space

[0230] 100 modules

[0231] 110 Module containment device.

Claims

1. A battery stack device, wherein: The battery stack device comprises: a plurality of battery cells having a component portion and including a first battery cell; a supporting member that supports the first battery cell and includes: a metal member that contains chromium; and a coating that covers the metal member; and a bonding member located between the first battery cell and the coating, The material of the coating is any one of aluminum oxide, magnesium oxide, silicon dioxide, titanium oxide, forsterite and cordierite. The coating layer has a second outer surface exposed to the 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.

2. The battery stack device according to claim 1, wherein: The thickness of the coating layer where the second outer surface is located is greater in a portion facing the flow path of the oxygen-containing gas than in a portion located away from the flow path.

3. The battery stack device according to claim 1, wherein: The thickness of the coating layer where the second outer surface is located is greater in a portion close to the element portion than in a portion far from the element portion.

4. The battery stack device according to any one of claims 1 to 3, wherein: The coating layer located between the second outer surface and the metal member has a greater porosity than the coating layer located between the first outer surface and the metal member.

5. The battery stack device according to any one of claims 1 to 3, wherein: The metal component has an upper surface and a side surface, The coating layer covering the upper surface has a thickness greater than the coating layer covering the side surfaces.

6. The battery stack device according to any one of claims 1 to 3, wherein: The metal member has a hole for fixing the first battery cell, the edge of the hole has a straight portion and a bent portion bent from the straight portion, and the coating layer covering the bent portion is thicker than the coating layer covering the straight portion.

7. The battery stack device according to any one of claims 1 to 3, wherein: The coating layer has a larger surface roughness than that of the metal member.

8. The battery stack device according to any one of claims 1 to 3, wherein: The engaging member is located between the first battery unit and the first outer surface, The surface roughness of the second outer surface is greater in a portion facing the flow path of the oxygen-containing gas than in a portion located away from the flow path.

9. The battery stack device according to any one of claims 1 to 3, wherein: The engaging member is located between the first battery unit and the first outer surface, The surface roughness of the second outer surface is greater at a portion close to the first battery cell than at a portion far from the first battery cell.

10. The battery stack device according to any one of claims 1 to 3, wherein: At least one element selected from the group consisting of Mn, Ti, Ca and Al is disposed at the interface between the metal component and the coating. The content of at least one of Mn, Ti, Ca and Al located at the interface is greater than the content of Mn, Ti, Ca and Al located at the metal member and the coating layer.

11. A module, wherein: The module has: The battery stack device according to any one of claims 1 to 10; and A storage container stores the battery stack device.

12. A module receiving device, wherein: The module receiving device comprises: The module according to claim 11; Auxiliary machines, used to operate the modules; and An outer casing houses the module and the auxiliary machine.

13. A coated metal member for supporting a battery cell of a battery stack device, wherein: The coated metal component comprises: Metal components containing chromium; and a coating covering the metal member, The material of the coating is any one of aluminum oxide, magnesium oxide, silicon dioxide, titanium oxide, forsterite and cordierite. The coating layer has a second outer surface exposed to the oxidizing atmosphere and a first outer surface located away from the oxidizing atmosphere, The thickness of the coating layer on the second outer surface is greater than the thickness of the coating layer on the first outer surface, or the surface roughness of the second outer surface is less than the surface roughness of the first outer surface.

14. The coated metal component according to claim 13, wherein: The thickness of the coating layer where the second outer surface is located is greater in a portion facing the flow path of the oxygen-containing gas than in a portion located away from the flow path.

15. The coated metal component according to claim 13 or 14, wherein: The coating layer located between the second outer surface and the metal member has a greater porosity than the coating layer located between the first outer surface and the metal member.

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