JP6484380B1 - Cell stack - Google Patents

Abstract

A cell stack capable of suppressing peeling of a coating film is provided. A current collecting member includes a base material made of an alloy material containing chromium, and a coating film covering the base material. The base material 302 is disposed in the main surface S1 facing the first fuel cell 300a, the side surface S2 continuous to the main surface S1, the concave portion 302b formed in the side surface S2, and the concave portion 302b, and is connected to the coating film 303. An anchor portion 302c. The anchor portion 302c extends in a direction away from the first fuel cell 300a, starting from an opening 302d formed in the side surface S2. [Selection] Figure 11

Description

  The present invention relates to a cell stack.

  Conventionally, a cell stack including a current collecting member that electrically connects two fuel cells is known (see Patent Document 1). The current collecting member of Patent Document 1 has a base material made of stainless steel and a coating film that covers the base material in order to suppress the volatilization of Cr (chromium) from the base material.

International Publication No. 2013/172451

  However, in the current collecting member described in Patent Document 1, there is a possibility that the coating film may be peeled off from the base material when an external force in a direction of pressing against the fuel cell is applied to the current collecting member.

  This invention is made | formed in view of the above-mentioned situation, and aims at providing the cell stack which can suppress peeling of a coating film.

  The cell stack according to the present invention includes an electrochemical cell and a current collecting member electrically connected to the electrochemical cell. The current collecting member has a base material made of an alloy material containing chromium and a coating film that covers at least a part of the base material. The substrate includes a main surface facing the electrochemical cell, a side surface continuous to the main surface, a recess formed in the side surface, and an anchor portion disposed in the recess and connected to the coating film. The anchor portion extends in a direction away from the electrochemical cell, starting from an opening formed on the side surface.

  ADVANTAGE OF THE INVENTION According to this invention, the cell stack which can suppress peeling of a coating film can be provided.

The perspective view of a cell stack apparatus. Sectional drawing of a cell stack apparatus. The perspective view of a fuel manifold. The perspective view of a fuel cell. Sectional drawing of a fuel cell. The elements on larger scale of FIG. The perspective view of a current collection member. AA sectional drawing of FIG. The enlarged view of area | region R1 of FIG. The enlarged view of area | region R2 of FIG. Partial enlarged view of FIG. Explanatory drawing of the manufacturing method of a current collection member Explanatory drawing of the manufacturing method of a current collection member Explanatory drawing of the manufacturing method of a current collection member Explanatory drawing of the manufacturing method of a current collection member Explanatory drawing of the manufacturing method of a current collection member Sectional drawing for demonstrating the structure of the modification 3. Sectional drawing which shows the structure of the coating film which concerns on the modification 11 Sectional drawing which shows the structure of the coating film which concerns on the modification 12.

  Hereinafter, an embodiment of a cell stack device using a current collecting member according to the present invention will be described with reference to the drawings. FIG. 1 is a perspective view of the cell stack apparatus 100. FIG. 2 is a cross-sectional view of the cell stack apparatus 100.

  As shown in FIGS. 1 and 2, the cell stack device 100 includes a fuel manifold 200 and a plurality of fuel cells 300.

[Fuel manifold]
FIG. 3 is a perspective view of the fuel manifold 200.

  As shown in FIG. 3, the fuel manifold 200 is configured to distribute fuel gas (for example, hydrogen) to each fuel cell 300. The fuel manifold 200 is hollow and has an internal space. Fuel gas is supplied to the internal space of the fuel manifold 200 through the introduction pipe 201. The fuel manifold 200 has a plurality of insertion holes 202 arranged at intervals. Each insertion hole 202 is formed in the top plate 203 of the fuel manifold 200. Each insertion hole 202 communicates with the internal space of the fuel manifold 200 and the outside.

[Fuel battery cell]
As shown in FIG. 2, each fuel cell 300 extends from the fuel manifold 200. Specifically, each fuel cell 300 extends upward (x-axis direction) from the top plate 203 of the fuel manifold 200. That is, the longitudinal direction (x-axis direction) of each fuel cell 300 extends upward. The length of each fuel cell 300 in the longitudinal direction (x-axis direction) can be about 100 to 300 mm.

The base end portion of each fuel cell 300 is inserted into the insertion hole 202 of the fuel manifold 200. Each fuel cell 300 is fixed to the insertion hole 202 by a bonding material 101. The fuel battery cell 300 is fixed to the fuel manifold 200 by the bonding material 101 in a state of being inserted into the insertion hole 202. The bonding material 101 is filled in a gap between the fuel battery cell 300 and the insertion hole 202. Examples of the bonding material 101 include crystallized glass, amorphous glass, brazing material, and ceramics. With crystallized glass, the ratio of “volume occupied by crystal phase” to the total volume (crystallinity) is 60% or more, and the ratio of “volume occupied by amorphous phase and impurities” to the total volume is less than 40%. Glass. Examples of such crystallized glass include SiO ₂ —B ₂ O ₃ system, SiO ₂ —CaO system, and SiO ₂ —MgO system.

  Each fuel cell 300 is formed in a plate shape extending in the longitudinal direction (x-axis direction) and the width direction (y-axis direction). The fuel cells 300 are arranged at intervals in the arrangement direction (z-axis direction). The interval between two adjacent fuel cells 300 is not particularly limited, but can be about 1 to 5 mm. Two adjacent fuel cells 300 are electrically connected by a current collecting member 301. A plurality of fuel cells 300 are connected by a current collecting member 301 to form a cell stack. The configuration of the current collecting member 301 will be described later.

  The fuel cell 300 includes a plurality of power generation element units 10 and a support substrate 20.

[Support substrate]
FIG. 4 is a perspective view of the fuel battery cell 300. FIG. 5 is a cross-sectional view of the fuel battery cell 300.

  As shown in FIG. 4, the support substrate 20 has a plurality of gas passages 21 extending along the longitudinal direction (x-axis direction) of the support substrate 20. Each gas flow path 21 extends from the proximal end side of the support substrate 20 toward the distal end side. Each gas channel 21 extends substantially parallel to each other. The base end side means the gas supply side of the gas flow path. Specifically, when the fuel battery cell 300 is attached to the fuel manifold 200, the side close to the fuel manifold 200 is meant. Further, the tip side means the side opposite to the gas supply side of the gas flow path. Specifically, when the fuel cell 300 is attached to the fuel manifold 200, it means the side far from the fuel manifold 200. For example, in the example shown in FIG. 2, the lower side is the proximal end side, and the upper side is the distal end side.

  As shown in FIG. 5, the support substrate 20 has a plurality of first recesses 22. In the present embodiment, each first recess 22 is formed on both main surfaces of the support substrate 20, but may be formed only on one main surface. The first recesses 22 are arranged at intervals in the longitudinal direction of the support substrate 20.

The support substrate 20 is made of a porous material that does not have electronic conductivity. The support substrate 20 can be made of, for example, CSZ (calcia stabilized zirconia). Alternatively, the support substrate 20 may be composed of NiO (nickel oxide) and YSZ (8YSZ) (yttria-stabilized zirconia), or composed of NiO (nickel oxide) and Y ₂ O ₃ (yttria). Alternatively, MgO (magnesium oxide) and MgAl ₂ O ₄ (magnesia alumina spinel) may be used. The porosity of the support substrate 20 is, for example, about 20 to 60%.

[Power generation element]
Each power generation element unit 10 is supported by a support substrate 20. In the present embodiment, each power generating element unit 10 is formed on both main surfaces of the support substrate 20, but may be formed only on one main surface. The power generation element units 10 are arranged at intervals in the longitudinal direction of the support substrate 20. That is, the fuel cell 300 according to the present embodiment is a so-called horizontal stripe fuel cell. The power generating element portions 10 adjacent in the longitudinal direction are electrically connected to each other by an interconnector 31.

  The power generation element unit 10 includes a fuel electrode 4, an electrolyte 5, and an air electrode 6. In addition, the power generation element unit 10 further includes a reaction preventing film 7.

[Fuel electrode]
The fuel electrode 4 is a fired body made of a porous material having electron conductivity. The fuel electrode 4 includes a fuel electrode current collector 41 and a fuel electrode active part 42.

  The fuel electrode current collector 41 is disposed in the first recess 22. Specifically, the fuel electrode current collector 41 is filled in the first recess 22 and has the same outer shape as the first recess 22. The fuel electrode current collector 41 has a second recess 411 and a third recess 412. A fuel electrode active portion 42 is disposed in the second recess 411. Further, the interconnector 31 is disposed in the third recess 412.

  The fuel electrode current collector 41 has electronic conductivity. The fuel electrode current collector 41 preferably has higher electron conductivity than the fuel electrode active part 42. The fuel electrode current collector 41 may or may not have oxygen ion conductivity.

The fuel electrode current collector 41 can be composed of, for example, NiO (nickel oxide) and YSZ (8YSZ) (yttria stabilized zirconia). Alternatively, the fuel electrode current collector 41 may be composed of NiO (nickel oxide) and Y ₂ O ₃ (yttria), or composed of NiO (nickel oxide) and CSZ (calcia stabilized zirconia). Also good. The thickness of the fuel electrode current collector 41 and the depth of the first recess 22 are about 50 to 500 μm.

  The fuel electrode active portion 42 has oxygen ion conductivity and electronic conductivity. The anode active part 42 has a higher content of oxygen ion conductive material than the anode current collector 41. Specifically, the volume ratio of the substance having oxygen ion conductivity with respect to the total volume excluding the pore portion in the fuel electrode active portion 42 is determined by the oxygen ion conduction in the total volume excluding the pore portion in the fuel electrode current collector 41. It is larger than the volume ratio of the substance having the property.

  The fuel electrode active part 42 may be composed of, for example, NiO (nickel oxide) and YSZ (8YSZ) (yttria stabilized zirconia). Alternatively, the fuel electrode active part 42 may be composed of NiO (nickel oxide) and GDC (gadolinium-doped ceria). The thickness of the fuel electrode active part 42 is 5 to 30 μm.

[Electrolytes]
The electrolyte 5 is disposed so as to cover the fuel electrode 4. Specifically, the electrolyte 5 extends in the longitudinal direction from one interconnector 31 to the adjacent interconnector 31. That is, the electrolyte 5 and the interconnector 31 are alternately and continuously arranged in the longitudinal direction (x-axis direction) of the support substrate 20. The electrolyte 5 is configured to cover the first main surface 23 a and the second main surface 23 b of the support substrate 20.

  The electrolyte 5 is a fired body made of a dense material that has ionic conductivity and no electronic conductivity. The electrolyte 5 can be made of, for example, YSZ (8YSZ) (yttria stabilized zirconia). Or the electrolyte 5 may be comprised from LSGM (lanthanum gallate). The thickness of the electrolyte 5 is, for example, about 3 to 50 μm.

[Reaction prevention film]
The reaction preventing film 7 is a fired body composed of a dense material. The reaction preventing film 7 is disposed between the electrolyte 5 and the air electrode active part 61. The reaction preventing film 7 suppresses occurrence of a phenomenon in which YSZ in the electrolyte 5 and Sr in the air electrode 6 react to form a reaction layer having a large electric resistance at the interface between the electrolyte 5 and the air electrode 6. Is provided.

The reaction preventing film 7 is made of a material containing ceria containing a rare earth element. The reaction preventing film 7 can be made of, for example, GDC = (Ce, Gd) O ₂ (gadolinium-doped ceria). The thickness of the reaction preventing film 7 is, for example, about 3 to 50 μm.

[Air electrode]
The air electrode 6 is a fired body composed of a porous material having electron conductivity. The air electrode 6 is disposed on the opposite side of the fuel electrode 4 with respect to the electrolyte 5. The air electrode 6 includes an air electrode active part 61 and an air electrode current collector 62.

  The air electrode active part 61 is disposed on the reaction preventing film 7. The air electrode active part 61 has oxygen ion conductivity and electron conductivity. The air electrode active part 61 has a higher content of a substance having oxygen ion conductivity than the air electrode current collecting part 62. Specifically, the volume ratio of the substance having oxygen ion conductivity with respect to the total volume excluding the pore portion in the air electrode active portion 61 is determined by the oxygen ion conductivity in the air electrode current collector 62 with respect to the total volume excluding the pore portion. It is larger than the volume ratio of the substance having the property.

The air electrode active part 61 can be composed of, for example, LSCF = (La, Sr) (Co, Fe) O ₃ (lanthanum strontium cobalt ferrite). Alternatively, the air electrode active part 61 may have LSF = (La, Sr) FeO ₃ (lanthanum strontium ferrite), LNF = La (Ni, Fe) O ₃ (lanthanum nickel ferrite), or LSC = (La, Sr) CoO. ₃ (lanthanum strontium cobaltite) or the like. The air electrode active part 61 may be configured by two layers of a first layer (inner layer) composed of LSCF and a second layer (outer layer) composed of LSC. The thickness of the air electrode active part 61 is, for example, 10 to 100 μm.

  The air electrode current collector 62 is disposed on the air electrode active part 61. The air electrode current collector 62 extends from the air electrode active part 61 toward the adjacent power generation element part. The fuel electrode current collector 41 and the air electrode current collector 62 extend from the power generation region to opposite sides. The power generation region is a region where the fuel electrode active part 42, the electrolyte 5, and the air electrode active part 61 overlap.

  The air electrode current collector 62 is a fired body made of a porous material having electronic conductivity. The air electrode current collector 62 preferably has higher electron conductivity than the air electrode active part 61. The air electrode current collector 62 may or may not have oxygen ion conductivity.

The air electrode current collector 62 can be made of, for example, LSCF = (La, Sr) (Co, Fe) O ₃ (lanthanum strontium cobalt ferrite). Alternatively, the air electrode current collector 62 may be made of LSC = (La, Sr) CoO ₃ (lanthanum strontium cobaltite). Or the air electrode current collection part 62 may be comprised from Ag (silver) and Ag-Pd (silver palladium alloy). The thickness of the air electrode current collector 62 is, for example, about 50 to 500 μm.

[Interconnector]
The interconnector 31 is configured to electrically connect the power generating element portions 10 adjacent in the longitudinal direction (x-axis direction) of the support substrate 20. Specifically, the air electrode current collector 62 of one power generation element unit 10 extends toward the other power generation element unit 10. Further, the fuel electrode current collector 41 of the other power generating element unit 10 extends toward the one power generating element unit 10. The interconnector 31 electrically connects the air electrode current collector 62 of one power generating element unit 10 and the fuel electrode current collector 41 of the other power generating element unit 10. The interconnector 31 is disposed in the third recess 412 of the fuel electrode current collector 41. Specifically, the interconnector 31 is embedded in the third recess 412.

The interconnector 31 is a fired body composed of a dense material having electronic conductivity. The interconnector 31 can be made of, for example, LaCrO ₃ (lanthanum chromite). Alternatively, the interconnector 31 may be made of (Sr, La) TiO ₃ (strontium titanate). The thickness of the interconnector 31 is, for example, 10 to 100 μm.

[Current collecting member]
FIG. 6 is a partially enlarged view of FIG. In FIG. 6, the vicinity of the base end portion of each fuel cell 300 in the cell stack device 100 is illustrated.

  As shown in FIG. 6, two adjacent fuel cells 300 (first fuel cell 300 a and second fuel cell 300 b) are electrically connected by a current collecting member 301.

  The current collecting member 301 is disposed between the first fuel cell 300a and the second fuel cell 300b. The current collecting member 301 is arranged closer to the base end side than the base end side power generating element part 10a arranged closest to the base end side among the plurality of power generating element parts 10 arranged on both main surfaces of the support substrate 20. Yes.

  The current collecting member 301 is joined to the base end sides of the first fuel cell 300a and the second fuel cell 300b. Specifically, the current collecting member 301 includes the electrical connection part 110 extending from the base-end power generation element part 10a of the first fuel cell 300a and the base of the second fuel battery cell 300b via the conductive bonding material 102. It is joined to the air electrode current collector 62 extending from the end-side power generating element portion 10a.

As the conductive bonding material 102, known conductive ceramics or the like can be used. For example, the conductive bonding material 102 is composed of at least one selected from (Mn, Co) ₃ O ₄ , (La, Sr) MnO ₃ , and (La, Sr) (Co, Fe) O _3. Can do.

  Here, FIG. 7 is a perspective view of the current collecting member 301, and FIG. 8 is a cross-sectional view taken along the line AA of FIG. FIG. 7 shows a state where the current collecting member 301 is joined to the first fuel cell 300a. In FIG. 7, the second fuel battery cell 300b is omitted, but actually, the second fuel battery cell 300b is arranged so as to face the first fuel battery cell 300a.

  The current collecting member 301 includes a first joint part a1, a second joint part a2, a first connection part b1, and a second connection part b2.

  The first joint part a1 is joined to the first fuel cell 300a. Specifically, the first joint portion a1 is joined to the electrical connection portion 110 that extends from the base-end-side power generation element portion 10a (see FIG. 6) of the first fuel cell 300a by the conductive joint material 102. The electrical connection unit 110 includes a first connection unit 111 and a second connection unit 112. The 1st connection part 111 can be set as the structure and material similar to the interconnector 31 mentioned above. The second connection portion 112 can be made of the same material as the air electrode current collector 62 described above. The second connection portion 112 is electrically connected to the first connection portion 111 and extends downward. As shown in FIG. 8, the first joint a1 has a main surface Sa that faces the outer surface Ta of the first fuel cell 300a.

  The 1st junction part a1 is formed in flat form. Although the thickness in particular of 1st junction part a1 in az axis direction is not restrict | limited, For example, it can be set as 0.1-2.0 mm. In the present embodiment, the first joint portion a1 is formed in a rectangular shape extending in the width direction, but the shape of the first joint portion a1 is not particularly limited, and is a triangle or more polygon, a circle, an ellipse, or Other complicated shapes may be used.

  A plurality of first through holes c1 are formed in the first joint portion a1. As shown in FIG. 8, each first through hole c <b> 1 has an inner wall surface Sc that is continuous with the main surface Sa. Each first through-hole c1 is filled with the conductive bonding material 102. Thereby, the joining force of the 1st junction part a1 with respect to the 1st fuel cell 300a can be improved. The conductive bonding material 102 may protrude outward from each first through hole c1, and may further spread on the outer surface of the first bonding portion a1.

  In the present embodiment, each first through-hole c1 is formed in a rectangular shape extending along the width direction, but the shape of each first through-hole c1 is not particularly limited, and is more than a circle, an ellipse, a triangle or more It may be a polygon or a complex shape other than these. In the present embodiment, three first through holes c1 are provided, but the number and position of the first through holes c1 can be changed as appropriate.

  The second joint a2 is electrically connected to the first joint a1. The second joint portion a2 is joined to the second fuel cell 300b. Specifically, the second joint portion a2 is joined to the air electrode current collector 62 extending from the base-end-side power generation element portion 10a (see FIG. 6) of the second fuel cell 300b by the conductive joint material 102. The second joint part a2 faces the first joint part a1 in the arrangement direction.

  The 2nd junction part a2 is formed in flat form. Although the thickness in particular of 2nd junction part a2 in az axis direction is not restrict | limited, For example, it can be set as 0.1-2.0 mm. In the present embodiment, the second joint part a2 has the same shape as the first joint part a1, but may have a different shape from the first joint part a1. There is no restriction | limiting in particular in the shape of 2nd junction part a2, Polygon more than a triangle, circular, an ellipse, or complicated shapes other than these may be sufficient.

  A plurality of second through holes c2 are formed in the second joint portion a2. Each second through-hole c2 is filled with the conductive bonding material 102. Thereby, the joining force of the 2nd junction part a2 with respect to the 2nd fuel cell 300b can be improved. The conductive bonding material 102 may protrude outward from each second through hole c2, and may further spread on the outer surface of the second bonding portion a2.

  In the present embodiment, each second through hole c2 is formed in a rectangular shape extending along the width direction, but the shape of each second through hole c2 is not particularly limited, and may be a circle, an ellipse, or a triangle or more. It may be a polygon or a complex shape other than these. In the present embodiment, three second through holes c2 are provided, but the number and position of the second through holes c2 can be changed as appropriate.

  The first and second connection parts b1 and b2 are connected to the first joint part a1 and the second joint part a2, respectively. In the present embodiment, the first and second connecting portions b1 and b2 are curved, but are not limited thereto. Each of the first and second connecting portions b1 and b2 may have a flat plate shape or a shape that bends at least at one place.

  In the present embodiment, the first and second connecting portions b1 and b2 are disposed at both ends of the current collecting member 301, but the positions of the first and second connecting portions b1 and b2 are not particularly limited.

[Internal structure of current collector]
Next, a detailed configuration of the current collecting member 301 (specifically, the first joint portion a1) will be described with reference to the drawings. FIG. 9 is an enlarged view of a region R1 in FIG.

  The current collecting member 301 includes a base material 302 and a coating film 303. The coating film 303 includes a chromium oxide film 303a and a coating film 303b.

  The base material 302 is made of an alloy material containing Cr (chromium). As such a metal material, Fe—Cr alloy steel (such as stainless steel) and Ni—Cr alloy steel can be used. Although the content rate of Cr in the base material 302 is not particularly limited, it can be 4 to 30% by mass.

The base material 302 may contain Ti (titanium) or Al (aluminum). The Ti content in the substrate 302 is not particularly limited, but is 0.01 to 1.0 at. %. The Al content in the substrate 302 is not particularly limited, but is 0.01 to 0.4 at. %. The base material 302 may contain Ti as TiO ₂ (titania) or may contain Al as Al ₂ O ₃ (alumina).

  The base material 302 has a main surface S1 facing the first fuel cell 300a (an example of a “fuel cell”), and a side surface S2 connected to the main surface S1. The main surface S1 is formed along the main surface Sa of the first joint a1. The side surface S2 is formed along the inner wall surface Sc of the first through hole c1 formed in the first joint portion a1. The main surface Sa of the first joint portion a1 and the inner wall surface Sc of the first through hole c1 are the outer surfaces of the coating film 303, respectively. The side surface S2 may be inclined with respect to the main surface S1, or may be substantially perpendicular to the main surface S1. The term “substantially vertical” means that not only the case of being vertical in a physically strict sense but also the case of being connected at an inclination of 15 ° or less. The main surface S1 extends along the xy plane. The side surface S2 extends along the yz plane. Each of the main surface S1 and the side surface S2 may be a substantially flat surface. The term “substantially flat” means not only the case of a plane in a physically strict sense, but also includes the case where there are minute irregularities and the case where there is a minute distortion entirely or partially.

  The base material 302 includes a base material main body 302a, a plurality of concave portions 302b (an example of “first concave portion”), and a plurality of anchor portions 302c (an example of “first anchor portion”). The substrate main body 302 a is a main body portion of the substrate 302. Each recess 302b is formed on the side surface S2. Each anchor portion 302 c is disposed in each recess 302 b and connected to the coating film 303. The configuration of each recess 302b and each anchor 302c will be described later.

  The coating film 303 covers at least a part of the base material 302 and is connected to each anchor portion 302c. In the present embodiment, the coating film 303 includes a chromium oxide film 303a and a coating film 303b.

  The chromium oxide film 303 a is formed on the base material 302. The chromium oxide film 303 a covers the base material 302. The chromium oxide film 303 a may cover a part of the substrate 302 or may cover the entire substrate 302.

  The chromium oxide film 303a is composed of chromium oxide. The thickness of the chromium oxide film 303a is not particularly limited, but can be, for example, 0.5 to 10 μm.

  The covering film 303b is formed on the chromium oxide film 303a. The coating film 303 b covers the base material 302. Specifically, the coating film 303 b covers a chromium oxide film 303 a formed on the base material 302. The coating film 303b may cover a part of the substrate 302 or may cover the entire substrate 302. The coating film 303b preferably covers a region of the base material 302 that comes into contact with the oxidant gas during the operation of the cell stack apparatus 100.

  The coating film 303 b suppresses Cr poisoning in the air electrode 6 of each fuel cell 300 by suppressing the volatilization of Cr from the base material 302. As a material constituting the coating film 303b, a ceramic material can be used. The specific type of the ceramic material can be appropriately selected according to the application location. In the present embodiment, since the current collecting member 301 is required to have conductivity, the ceramic material is composed of a perovskite complex oxide containing La and Sr, and a transition metal such as Mn, Co, Ni, Fe, and Cu. Spinel type complex oxide can be used. However, the coating film 303b only needs to suppress the volatilization of Cr, and the constituent material is not limited to the ceramic material. The thickness of the coating film 303b is not particularly limited, but may be 1 to 200 μm, for example.

[Configuration of recess and anchor part]
Next, the configuration of each concave portion 302b (an example of “concave portion”) and each anchor portion 302c (an example of “anchor portion”) included in the base material 302 will be described with reference to the drawings. FIG. 10 is an enlarged view of a region R2 in FIG. FIG. 10 corresponds to a cross section perpendicular to the side surface S <b> 2 of the substrate 302.

  The recess 302b is formed on the side surface S2 of the substrate 302. The recess 302b extends from the opening 302d formed in the side surface S2 toward the inside of the base body 302a. As shown in FIG. 10, the recess 302b extends from the opening 302d in the direction away from the first fuel cell 300a.

  The anchor portion 302c is disposed in the recess 302b. The anchor portion 302c is connected to the coating film 303 in the vicinity of the opening 302d of the recess 302b. In this embodiment, since the chromium oxide film 303a is interposed between each anchor portion 302c and the coating film 303b, each anchor portion 302c is connected to the chromium oxide film 303a. However, when the chromium oxide film 303a is not interposed between each anchor portion 302c and the coating film 303b, each anchor portion 302c is connected to the coating film 303b.

  The anchor portion 302c extends in a direction away from the first fuel cell 300a, starting from the opening 302d of the recess 302b. Thus, the anchor effect is generated in the coating film 303 by the anchor portion 302c being locked to the recess 302b. Therefore, since the adhesion of the coating film 303 to the base material 302 is improved, the coating film 303 can be prevented from peeling from the base material 302. In particular, since the anchor portion 302c extends obliquely in a direction away from the first fuel battery cell 300a, even if an external force in a direction to be pressed against the first fuel battery cell 300a is applied to the current collecting member 301, the coating film It can suppress effectively that 303 peels. In addition, since the anchor portion 302c extends obliquely in the direction away from the first fuel battery cell 300a, it is possible to prevent the current path from being hindered by the anchor portion 302c and the base material 302 from being heated and deteriorated.

  The anchor portion 302c may be filled in the entire recess 302b, or may be disposed in a part of the recess 302b. Therefore, pores do not have to exist in the recess 302b, or pores may partially exist.

  Here, FIG. 11 is a partially enlarged view of FIG.

  The base material 302 according to the present embodiment has three recesses 302b (an example of “plurality of first recesses”) and three anchor portions 302c (an example of “plurality of first anchor portions”) in a cross section perpendicular to the side surface S2. ). The two recesses 302b are formed in a linear wedge shape and extend substantially parallel to each other. The remaining one recess 302b is formed in a generally curved shape.

  Here, the side surface S2 includes a first region S21 and a second region S22. The first region S21 is separated from the main surface S1. The second region S22 is continuous with the main surface S1 and the first region S21. That is, the first region S21 is a region away from the first fuel cell 300a in the side surface S2, and the second region S22 is a region near the first fuel cell 300a in the side surface S2. Although 1st area | region S21 is not specifically limited, For example, it occupies the range of about 10 to 90% among side surface S2. Although 2nd area | region S22 is not specifically limited, For example, it occupies the range of about 10 to 90% among side surface S2. The boundary between the first region S21 and the second region S22 is defined by a line along a direction substantially parallel to the boundary between the first main surface S1 and the side surface S2 (that is, the y-axis direction).

  In the present embodiment, each recess 302b is formed in the second region S22 of the side surface S2. Accordingly, the anchor portion 302c is disposed at a position relatively close to the first fuel cell 300a in the base body 302a. As described above, since the anchor portion 302c is located in the second region S22 in which high stress is generated due to the thermal expansion of the first fuel battery cell 300a and the coating film 303 is likely to be peeled off, the coating film 303 is peeled off. Can be efficiently suppressed.

  Anchor portion 302c preferably contains an oxide of an element having an equilibrium oxygen pressure lower than that of Cr (chromium) (hereinafter referred to as “low equilibrium oxygen pressure element”). That is, the anchor portion 302c preferably contains an oxide of a low equilibrium oxygen pressure element that has a higher affinity with oxygen than Cr and is easily oxidized. As a result, during operation of the cell stack 100, oxygen that permeates the coating film 303b can be preferentially taken into the anchor portion 302c, so that the base body 302a surrounding the anchor portion 302c is oxidized and the anchor portion 302c is oxidized. Can suppress the enlargement. As a result, since the anchor effect can be maintained over a long period by maintaining the shape of the anchor portion 302c, the peeling of the coating film 303 can be suppressed over a long period.

Examples of the low equilibrium oxygen pressure element include Al (aluminum), Ti (titanium), Ca (calcium), Si (silicon), Mn (manganese), and the oxides include Al ₂ O ₃ and TiO _2. , CaO, SiO ₂ , MnO, MnCr ₂ O _{4 and the} like, but are not limited thereto.

  The content of the low equilibrium oxygen pressure element in the anchor portion 302c is not particularly limited, but when the molar ratio of each element to the total of the elements other than oxygen among all the constituent elements is defined as the cation ratio, the cation ratio is 0.01 or more. Is preferred. Thereby, since the oxidation of the base body 302a surrounding the anchor portion 302c can be further suppressed, the adhesion of the chromium oxide film 303a to the base 302 can be maintained for a longer period. The content of the element having an equilibrium oxygen pressure lower than that of Cr in the anchor portion 302c is more preferably 0.05 or more, and particularly preferably 0.10 or more in terms of cation ratio.

  The content of the low equilibrium oxygen pressure element in the anchor portion 302c is obtained as follows. First, about 20 anchor portions 302c randomly selected from images in which the cross section of the substrate 302 was magnified 1000 to 20000 times by FE-SEM (Field Emission-Scanning Electron Microscope). Using an EDS (energy dispersive X-ray spectrometer), the content of low equilibrium oxygen pressure elements at 10 points that divide the actual length L1 of the anchor portion 302c into 11 parts is measured by a cation ratio. Next, the maximum value is selected from the content rates measured at 10 points for every 20 anchor portions 302c. Next, the maximum value selected for each of the 20 anchor portions 302c is arithmetically averaged. The value obtained by this arithmetic average is the content of the low equilibrium oxygen pressure element in the anchor portion 302c. When 20 anchor portions 302c cannot be observed in one cross section, 20 anchor portions 302c may be selected from a plurality of cross sections. As shown in FIG. 11, the actual length L1 of the anchor portion 302c is the portion of the anchor portion 302c embedded in the recess 302b in the direction parallel to the side surface S2 of the base material 302 (z-axis direction). The length of the line connecting the midpoints.

The anchor portion 302c may contain only one kind of oxide of a low equilibrium oxygen pressure element, or may contain two or more kinds. For example, the anchor portion 302c may contain only Al ₂ O ₃ as an oxide of a low equilibrium oxygen pressure element, or may contain a mixture of Al ₂ O ₃ and TiO ₂ .

  In addition, the anchor part 302c may contain chromium oxide. However, the chromium content in the anchor portion 302c is preferably 0.95 or less, more preferably 0.90 or less in terms of cation ratio.

  The actual length L1 of the anchor portion 302c is not particularly limited, but is preferably 15 μm or more. Thereby, a sufficient anchor effect can be produced by the anchor portion 302c. The actual length L1 of the anchor portion 302c is more preferably 20 μm or more, and particularly preferably 30 μm or more.

  The vertical depth D1 of the anchor portion 302c is not particularly limited, but is preferably 15 μm or more. Thereby, a sufficient anchor effect can be produced by the anchor portion 302c. As shown in FIG. 11, the vertical depth D1 of the anchor portion 302c is the depth of the portion embedded in the recess 302b in the anchor portion 302c in the direction perpendicular to the side surface S2 of the base material 302 (x-axis direction). It is. The vertical depth D1 of the anchor portion 302c is more preferably 17 μm or more, and particularly preferably 20 μm or more.

  The width W1 of the anchor portion 302c is not particularly limited, but is preferably 0.5 μm or more. Thereby, a sufficient anchor effect can be produced by the anchor portion 302c. As shown in FIG. 11, the width W1 of the anchor portion 302c is determined by measuring the shortest width of the anchor portion 302c at four locations that divide the actual length L1 into five equal parts. It is a value obtained by arithmetically averaging Wc and Wd. The width W1 of the anchor portion 302c is more preferably 0.7 μm or more, and particularly preferably 1.0 μm or more.

  The angle θ1 of the anchor portion 302c with respect to the side surface S2 is not particularly limited, but is preferably 60 degrees or less. Thereby, a sufficient anchor effect can be produced by the anchor portion 302c. As shown in FIG. 11, the angle θ1 of the anchor portion 302c is an angle formed by a straight line connecting the center point of the opening 302d and the deepest point of the anchor portion 302c and the side surface S2. The angle θ1 of the anchor portion 302c is more preferably 50 degrees or less, and particularly preferably 40 degrees or less.

  In addition, the base material 302 should just have the recessed part 302b and the anchor part 302c at least 1 each, and the number can be changed suitably. Moreover, when the base material 302 has the some recessed part 302b and the some anchor part 302c, each anchor part 302c may be extended in the mutually parallel direction, and may be extended in a different direction. Moreover, the cross-sectional shape and size of each anchor part 302c may be the same as each other, or may be different. In FIG. 11, the anchor portion 302c formed in a linear wedge shape and the anchor portion 302c formed in a curved wedge shape are illustrated, but the cross-sectional shape of the anchor portion 302c is not limited thereto. The cross-sectional shape of the anchor portion 302c may be curved or bent entirely or partially, or may have a shape other than a wedge shape (frustum shape, rectangular shape, other complex shape, etc.).

[Manufacturing method of current collecting member]
A method for manufacturing the current collecting member 301 will be described with reference to the drawings.

  First, as shown in FIG. 12, a desired number of recesses 302b are formed in the second region S22 of the side surface S2 of the substrate 302. The concave portion 302b can be formed, for example, by spraying sandblast obliquely. At this time, the actual length L1 and the width W1 of the recess 302b can be adjusted by adjusting the particle size of the abrasive or leveling the side surface S2 with a roller.

  Next, as shown in FIG. 13, a paste containing an oxide of a low equilibrium oxygen pressure element is applied onto the side surface S <b> 2 of the base material 302, thereby filling the inside of the recess 302 b with the paste. The paste is prepared by adding ethyl cellulose and terpineol to an oxide powder of a low equilibrium oxygen tension element.

  Next, as shown in FIG. 14, the excess paste remaining on the side surface S2 is removed using, for example, a squeegee.

  Next, as shown in FIG. 15, the base material 302 is heat-treated (800 to 900 ° C. for 5 to 20 hours) in an air atmosphere to solidify the paste filled in the recess 302 b to form the anchor portion 302 c. At the same time, a chromium oxide film 303a covering the substrate 302 is formed.

  Next, as shown in FIG. 16, a coating film 303b is formed by applying a ceramic material paste on the chromium oxide film 303a and then performing heat treatment (800 to 900 ° C. for 1 to 5 hours).

(Modification of the embodiment)
As mentioned above, although embodiment of this invention was described, this invention is not limited to these, A various change is possible unless it deviates from the meaning of this invention.

[Modification 1]
In the above-described embodiment, the case where the current collecting member 301 according to the present invention is applied to a horizontally-striped fuel cell has been described. However, the present invention can also be applied to a so-called vertically-striped fuel cell. Vertically-striped fuel cells are arranged on the other main surface of the conductive support substrate, the power generation unit (fuel electrode, solid electrolyte layer, and air electrode) disposed on one main surface of the support substrate. Interconnector. The metal member for an electrochemical cell according to the present invention can be applied to a solid oxide electrochemical cell including a solid oxide electrolytic cell in addition to a fuel cell.

[Modification 2]
In the above embodiment, the configuration of the current collecting member 301 has been described with reference to FIG. 7, but the specific configuration of the current collecting member 301 can be changed as appropriate. For example, the current collecting member 301 may have three or more joint portions, and a through hole may not be formed in the joint portion.

[Modification 3]
In the above embodiment, the concave portion is not formed in the first region S21 of the side surface S2 of the base material 302. However, the concave portion may also be formed in the first region S21 of the side surface S2.

  For example, as shown in FIG. 17, the base material 302 includes a base body 302a, a plurality of first recesses 302e, a plurality of first anchor portions 302f, a plurality of second recesses 302g, and a plurality of second anchors. Part 302h.

  Each first recess 302e has the same configuration as the recess 302b according to the above embodiment, and each first anchor portion 302f has the same configuration as the anchor portion 302c according to the above embodiment.

  Each 2nd recessed part 302g is formed in 1st area | region S21 among the side surfaces S2. Each second recess 302g extends from the opening 302k formed in the first region S21 of the side surface S2 toward the inside of the base body 302a. In FIG. 17, each second recess 302g extends in a direction substantially perpendicular to the side surface S2, but the direction in which each second recess 302g extends is not particularly limited.

  Each second anchor portion 302h is disposed in the second recess 302g. The second anchor portion 302h is connected to the coating film 303 in the vicinity of the opening 302k of the recess 302g. By providing such a second anchor portion 302h, it is possible to further improve the adhesion of the coating film 303 to the base material 302, so that the coating film 303 can be further prevented from peeling from the base material 302.

  The numbers of the first anchor part 302f and the second anchor part 302h are not particularly limited. Therefore, the base material 302 may have only one second recess 302g in a cross section perpendicular to the side surface S2.

  The actual length of the second anchor portion 302h is preferably shorter than the actual length L1 of the first anchor portion 302f. As a result, not only the effect of preventing the peeling of the coating film 303 due to the anchor effect can be improved, but also the current interruption by the anchor portion can be reduced. The actual length of the second anchor portion 302h is measured by the same method as the actual length L1 of the anchor portion 302c described in the above embodiment.

  The vertical depth of the second anchor portion 302h is preferably shorter than the vertical depth D1 of the first anchor portion 302f. Thereby, it can suppress that the flow of the electric current between the current collection member 301 and the 1st fuel cell 300a is inhibited by the 2nd anchor part 302h. The vertical depth of the second anchor portion 302h is measured by the same method as the vertical depth D1 of the anchor portion 302c described in the above embodiment.

  The width of the second anchor portion 302h is preferably narrower than the width W1 of the first anchor portion 302f. Thereby, it can be reduced that the second anchor portion 302h hinders the flow of current in the side surface S2. The width of the second anchor portion 302h is measured by the same method as the width W1 of the anchor portion 302c described in the above embodiment.

[Modification 4]
In the above embodiment, each recess 302b is formed only in the second region S22 of the side surface S2, but the present invention is not limited to this. Each recessed part 302b may be formed only in 1st area | region S21 among side surface S2, and may be formed in both 1st area | region S21 and 2nd area | region S22.

[Modification 5]
The current collecting member 301 has a main body portion constituted by a base material 302 and a chromium oxide film 303a. The main body has a first main surface facing the first fuel cell 300a side, a second main surface opposite to the first main surface, and side surfaces continuous to the first main surface and the second main surface. The side surface includes a first region on the first fuel cell 300a side and a second region on the opposite side to the first fuel cell 300a. The first region occupies a range of about 10 to 90% of the side surface. The second region occupies a range of about 10 to 90% of the side surface.

  Here, the surface roughness in the second region can be made larger than the surface roughness in the first region. According to this configuration, the coating film 303b is more easily formed on the side surface of the current collecting member 301 in the second region than in the first region. As a result, since the second region is surely covered with the coating film 303b, the oxidation in the second region can be suppressed even if the oxidizing gas is supplied to the outer surface of the first fuel cell 300a.

  In the present modification, the thickness of the coating film 303b in the second region is preferably thicker than the thickness of the coating film 303b in the first region. By comprising in this way, oxidation can be further suppressed in a region that is easily exposed to the oxidant gas. The thickness of the coating film 303b in the first region is preferably larger than the thickness of the coating film 303b in the second region. By comprising in this way, when the base-material main-body part 302a is the metal containing chromium, by suppressing the volatilization of chromium from a main-body part in the area | region near the 1st fuel cell 300a, it is 1st. Chromium poisoning in the fuel cell 300a can be further suppressed. In addition, the surface roughness in the second region is preferably larger than the surface roughness in the first and second main surfaces.

[Modification 6]
The current collecting member 301 has a main body portion constituted by a base material 302 and a chromium oxide film 303a. The main body has a first main surface facing the first fuel cell 300a side, a second main surface opposite to the first main surface, and side surfaces continuous to the first main surface and the second main surface. The side surface includes a first region on the first fuel cell 300a side and a second region on the opposite side to the first fuel cell 300a. The first region occupies a range of about 10 to 90% of the side surface. The second region occupies a range of about 10 to 90% of the side surface.

  Here, the surface roughness in the first region can be larger than the surface roughness in the second region. According to this configuration, since the surface roughness in the first region is larger than the surface roughness in the second region among the side surfaces of the current collecting member 301, peeling of the coating film 303b in the first region can be suppressed. . Further, since the surface roughness of the second region is smaller than the surface roughness of the first region, the surface area of the second region, which is easily oxidized when an oxidant gas is flowed to the outer surface of the first fuel cell 300a, is reduced. Can suppress oxidation.

  In this modification, it is preferable that the thickness of the coating film 303b in the first region is thicker than the thickness of the coating film 303b in the second region. By comprising in this way, when the base-material main-body part 302a is a metal containing chromium, the chromium poisoning in the 1st fuel cell 300a is suppressed more by suppressing the volatilization of chromium from a main-body part more. be able to. The thickness of the coating film 303b in the second region is preferably thicker than the thickness of the coating film 303b in the first region. By comprising in this way, oxidation can be further suppressed in a region that is easily exposed to the oxidant gas. In addition, the surface roughness in the first region is preferably larger than the surface roughness in the first and second main surfaces.

[Modification 7]
The current collecting member 301 has a main body portion constituted by a base material 302 and a chromium oxide film 303a. The main body has a first main surface facing the first fuel cell 300a side, a second main surface opposite to the first main surface, and a pair of side surfaces continuous to the first main surface and the second main surface. .

  Here, the area of the second main surface can be made smaller than the area of the first main surface. According to this configuration, the second main surface on the side exposed to the oxidant gas among the pair of main surfaces of the current collecting member 301 has a smaller area than the first main surface. For this reason, compared with the current collection member 301 which has the 2nd main surface of the same area as a 1st main surface like the past, the 2nd main surface can be more reliably covered with the coating film 303b. Moreover, since the first main surface has a larger area than the second main surface, the junction area between the current collecting member 301 and the first fuel cell 300a is increased, and the electrical resistance can be reduced.

  In the present modification, in the cross section perpendicular to the first main surface, the pair of side surfaces are preferably inclined so as to approach each other toward the second main surface. According to this configuration, since the bonding area between the pair of side surfaces and the coating film 303b is larger than when the pair of side surfaces are not inclined, the bonding strength with the coating film 303b can be improved. Moreover, it is preferable that the angle which a 2nd main surface and at least one side surface make is an obtuse angle. A corner portion which is a boundary portion between the second main surface and the side surface is disposed at a position where it is easily exposed to the oxidant gas flowing on the outer surface of the first fuel cell 300a. By making the angle of the corner between the second main surface and the side surface an obtuse angle, the coating film 303b can be easily formed on the corner, and the coating film 303b can be more reliably formed.

[Modification 8]
The current collecting member 301 has a main body portion constituted by a base material 302 and a chromium oxide film 303a. The main body has a first main surface facing the first fuel cell 300a side, a second main surface opposite to the first main surface, and side surfaces continuous to the first main surface and the second main surface.

  Here, the main body portion further includes a protruding portion protruding in a direction in which the first main surface faces from a corner portion formed by the first main surface and the side surface, and a curved surface connecting the second main surface and the side surface. It may be. According to this configuration, since the main body portion has the protruding portion that protrudes toward the first fuel cell 300a, the adhesion between the main body portion and the coating film 303b can be improved. As a result, peeling of the coating film 303b can be suppressed. In addition, since the corner opposite to the protrusion is formed by a curved surface, it is easy to form the coating film 303b, and the coating film 303b can be more reliably formed.

[Modification 9]
The current collecting member 301 has a main body portion constituted by a base material 302 and a chromium oxide film 303a. The main body has a first main surface facing the first fuel cell 300a side, a second main surface opposite to the first main surface, and side surfaces continuous to the first main surface and the second main surface.

  Here, the main body further includes a protruding portion that protrudes in a direction in which the second main surface faces from a corner portion formed by the second main surface and the side surface, and a curved surface that connects the first main surface and the side surface. It may be. According to this configuration, since the first main surface and the side surface are connected by the curved surface on the first fuel cell 300a side, the first main surface and the side surface are directly connected to form a corner portion. As compared with the main body portion, current concentration can be suppressed. As a result, oxidation in this part can be suppressed. In addition, since the protruding portion protrudes in a direction in which the second main surface faces from the corner portion formed by the second main surface and the side surface, the protruding portion is preferentially oxidized to suppress oxidation of other portions. it can.

[Modification 10]
The current collecting member 301 has a main body portion constituted by a base material 302 and a chromium oxide film 303a. The main body has a first main surface facing the first fuel cell 300a side, a second main surface opposite to the first main surface, and side surfaces continuous to the first main surface and the second main surface. The side surface includes a first region on the first fuel cell 300a side and a second region on the opposite side to the first fuel cell 300a. The first region occupies a range of about 10 to 90% of the side surface. The second region occupies a range of about 10 to 90% of the side surface.

  Here, the side surface may have a step portion formed between the first region and the second region. According to this configuration, the stepped portion can improve the adhesion with the coating film 303b, and therefore, the peeling of the coating film 303b from the main body portion can be suppressed.

  In this modification, it is preferable that the step portion is oriented in the direction in which the second main surface is oriented. In this case, in the cross section perpendicular to the first main surface, the pair of side surfaces of the main body portion is preferably inclined so as to approach each other toward the second main surface. If the angle formed by the direction in which the step portion faces and the direction in which the second main surface faces is within 45 degrees, it can be said that the step portion faces in the direction in which the second main surface faces. Further, the step portion faces the direction in which the first main surface faces. In this case, in a cross section perpendicular to the first main surface, it is preferable that the pair of side surfaces of the main body portion be inclined so as to approach each other toward the first main surface. If the angle between the direction in which the step portion faces and the direction in which the first main surface faces is within 45 degrees, it can be said that the step portion faces in the direction in which the first main surface faces.

  In this modification, when the side surface is viewed along the direction orthogonal to the side surface, the end portion of the first region on the second main surface side and the end portion of the second region on the first main surface side overlap each other. Thus, it is preferable that the step portion is configured. According to this configuration, since the adhesion between the stepped portion and the coating film 303b is further improved, the peeling of the coating film 303b from the main body portion can be more reliably suppressed.

[Modification 11]
In the above embodiment, the coating film 303 includes the chromium oxide film 303a and the coating film 303b. However, it is sufficient that the coating film 303 includes at least the coating film 303b. For example, as shown in FIG. 18, the coating film 303 may substantially include only the coating film 303b. The actual length L1, the vertical depth D1, and the bonding width W1 of each anchor portion 302c are as described in the above embodiment. Even in the configuration shown in FIG. 18, it is assumed that an external force applied to the first fuel cell 300a is applied to the current collecting member 301 by extending each anchor portion 302c in a direction away from the first fuel cell 300a. Moreover, it can suppress that the coating film 303 peels. The coating film 303 including only the coating film 303b can be formed by embedding a paste for a buried portion in the recess 302b, and then applying a heat treatment by applying the paste for the coating film.

[Modification 12]
In the above embodiment, each anchor portion 302 c is connected to the chromium oxide film 303 a in the coating film 303. However, as shown in FIG. 19, each anchor portion 302 c is a coating film in the coating film 303. It may be connected to 303b. In this case, a part of each anchor portion 302 c protrudes from the recess 302 b of the base material 302, and the remaining portion of each anchor portion 302 c is embedded in the recess 302 b of the base material 302. It is a portion of each anchor portion 302c that is embedded in the recess 302b that exerts an anchor effect on the base material 302. Therefore, the actual length L1, the vertical depth D1, and the joining width W1 of each anchor portion 302c are calculated using only the portion embedded in the concave portion 302b of each anchor portion 302c as a measurement target. Even in the configuration shown in FIG. 19, it is assumed that an external force in a direction to be pressed against the first fuel cell 300a is applied to the current collecting member 301 by extending each anchor portion 302c in a direction away from the first fuel cell 300a. Moreover, it can suppress that the coating film 303 peels. In order to connect each anchor portion 302 c to the coating film 303 b of the coating film 303, the anchor portion paste is embedded in the recess 302 b, and then the coating film paste is applied onto the substrate 302. The chromium oxide film 303a may be deposited between the base material 302 and the coating film 303b by further heat treatment while forming the coating film 303b by heat treatment.

DESCRIPTION OF SYMBOLS 100 Cell stack 102 Conductive joining material 200 Fuel manifold 300 Fuel cell 300a 1st fuel cell 300b 2nd fuel cell 301 Current collecting member 302 Base material 302a Base material main part 302b Recessed part 302c Anchor part 302d Opening 302e 1st recessed part 302f 1st anchor part 302g 2nd recessed part 302h 2nd anchor part 302k Opening S1 Main surface S2 Side surface 303 Coating film 303a Chromium oxide film 303b Coating film

Claims (10)

An electrochemical cell;
A current collecting member electrically connected to the electrochemical cell;
With
The current collecting member is
A substrate composed of an alloy material containing chromium;
A coating film covering at least a part of the substrate;
Have
The substrate is
A main surface facing the electrochemical cell;
A side surface continuous with the main surface;
A first recess formed in the side surface;
A first anchor portion disposed in the first recess and connected to the coating film;
Including
The first anchor portion starts from an opening formed in the side surface and extends in a direction away from the electrochemical cell,
The first anchor portion contains an oxide containing an element having a lower equilibrium oxygen pressure than chromium.
Cell stack. An electrochemical cell;
A current collecting member electrically connected to the electrochemical cell;
With
The current collecting member is
A substrate composed of an alloy material containing chromium;
A coating film covering at least a part of the substrate;
Have
The substrate is
A main surface facing the electrochemical cell;
A side surface continuous with the main surface;
A first recess formed in the side surface;
A first anchor portion disposed in the first recess and connected to the coating film;
Including
The first anchor portion starts from an opening formed in the side surface and extends in a direction away from the electrochemical cell,
In a cross section perpendicular to the side surface, an angle of the first anchor part with respect to the side surface is 60 degrees or less.
Cell stack. The side surface includes a first region separated from the main surface, and a second region continuous with the main surface and the first region,
The first recess is formed in the second region of the side surface.
The cell stack according to claim 1 or 2 . The actual length of the first anchor portion is 15 μm or more.
Cell stack according to any one of claims 1 to 3. The first anchor portion has a width of 0.5 μm or more.
Cell stack according to any one of claims 1 to 4. The substrate is
A plurality of first recesses including the first recess;
A plurality of first anchor portions each including the first anchor portion and extending in a direction away from the electrochemical cell starting from an opening formed in the side surface;
The cell stack according to any one of claims 1 to 5 . In a cross section perpendicular to the side surface, each of the plurality of first anchor portions is parallel.
The cell stack according to claim 6 . The substrate is
A second recess formed in the first region;
A second anchor portion disposed in the second recess and connected to the coating film;
Having
The cell stack according to claim 3 . The actual length of the second anchor part is shorter than the actual length of the first anchor part,
The cell stack according to claim 8 . The width of the second anchor part is narrower than the width of the first anchor part,
The cell stack according to claim 8 or 9 .

Images