JP6554585B1 - Metal member for electrochemical cell, and electrochemical cell assembly using the same - Google Patents

Abstract

Provided is a metal member that can more reliably cover a second main surface of the metal member with a coating layer. A metal member for an electrochemical cell includes a main body part and a coating layer. The main body 311 has a first main surface Sa1, a second main surface Sa2, and a pair of side surfaces Sa3. The first main surface Sa1 faces the electrochemical cell 300a side. The second main surface Sa2 is a main surface opposite to the first main surface Sa1. The covering layer 317 covers the main body portion 311. The area of the second main surface Sa2 is smaller than the area of the first main surface Sa1. [Selection] Figure 8

Description

  The present invention relates to a metal member for an electrochemical cell and an electrochemical cell assembly using the same.

  In recent years, attention has been focused on cell stacks using fuel cells, which are a type of electrochemical cell, from the viewpoint of environmental problems and effective use of energy resources. Fuel cells generally have a fuel electrode, an air electrode, and a solid electrolyte layer. The cell stack has a plurality of fuel cells. In order to electrically connect adjacent fuel cells to each other, a current collecting member which is a metal member is joined to each fuel cell. In addition, a metal member may be joined to the fuel cell in other applications such as extracting current from the fuel cell.

JP 2014-127427 A

  The current collecting member has a main body and a covering layer covering the main body. The main body portion has a first main surface, a second main surface, and a side surface. The first main surface of the current collection member faces the fuel cell side, and is joined to the fuel cell via a bonding material. The second major surface is opposite to the first major surface. When the oxidant gas such as air is supplied to the outer surface of the fuel cell, the second principal surface of the pair of principal surfaces of the current collection member is the principal surface exposed to the oxidant gas. For this reason, it is preferable to cover the 2nd main surface side more reliably with a coating layer. Then, the subject of this invention is providing the metal member which can cover the 2nd main surface of a metal member more reliably by a coating layer.

  The metal member for an electrochemical cell according to the first aspect of the present invention is a metal member joined to the electrochemical cell. The electrochemical cell metal member comprises a main body and a cover layer. The main body portion has a first main surface, a second main surface, and a pair of side surfaces. The first major surface faces the electrochemical cell. The second main surface is the main surface opposite to the first main surface. The coating layer covers the main body. The area of the second major surface is smaller than the area of the first major surface.

  According to this configuration, of the pair of main surfaces of the metal member, the second main surface on the side exposed to the oxidant gas has a smaller area than the first main surface. For this reason, compared with the metal member which has the 2nd main surface of the same area as a 1st main surface like the past, a 2nd main surface can be more reliably covered with a coating layer. Moreover, since the area of the first main surface is larger than that of the second main surface, the bonding area between the metal member and the electrochemical cell is increased, and the electrical resistance can be reduced.

  Preferably, the pair of side surfaces slopes toward each other toward the second major surface. According to this configuration, since the bonding area between the pair of side surfaces and the coating layer is larger than when the pair of side surfaces are not inclined, the bonding strength with the coating layer can be improved.

  Preferably, an angle formed by the second main surface and at least one side surface 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 electrochemical cell. By making the angle of the corner between the second main surface and the side face an obtuse angle, the formation of the covering layer on the corner can be facilitated, and the covering layer can be formed more reliably.

  Preferably, the side surface has a first region on the first main surface side and a second region on the second main surface side.

  Preferably, the thickness of the covering layer in the second region is thicker than the thickness of the covering layer in the first region.

  Preferably, the thickness of the covering layer in the first region is thicker than the thickness of the covering layer in the second region.

  Preferably, the surface roughness in the second region is larger than the surface roughness in the first region.

  Preferably, the side surface has a stepped portion formed between the first region and the second region.

  Preferably, the main body has a through hole. And the inner wall surface of this through-hole is comprised by the side mentioned above.

  Preferably, the surface roughness in the second region is larger than the surface roughness in the first and second main surfaces.

  An electrochemical cell assembly according to a second aspect of the present invention includes an electrochemical cell, any one of the above-described electrochemical cell metallic members, and a conductive bonding material. The electrochemical cell metal member is disposed with the first major surface facing the electrochemical cell. The conductive bonding material bonds the metal member to the electrochemical cell.

  According to the present invention, the second main surface of the metal member can be more reliably covered with the coating layer.

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. Sectional drawing of the base end side of a fuel cell. The perspective view of a current collection member. AA sectional drawing of FIG. The top view of a 1st junction part. Sectional drawing of the part between a pair of side surfaces among 1st junction parts. Sectional drawing of the current collection member which concerns on a modification. Sectional drawing which shows an example of the manufacturing method of the 1st junction part which concerns on a modification. The expanded sectional view of the side surface of the 1st junction part which concerns on a modification. The expanded sectional view of the side surface of the 1st junction part which concerns on a modification.

  Hereinafter, an embodiment of a cell stack device using a current collecting member which is an example of a metal member for an electrochemical cell according to the present invention will be described with reference to the drawings.

  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]
As shown in FIG. 3, the fuel manifold 200 is configured to distribute a fuel gas (for example, hydrogen or the like) to each of the fuel cells 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 via the inlet pipe 201. The fuel manifold 200 has a plurality of insertion holes 202 spaced apart from one another. 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 cell]
As shown in FIG. 2, each fuel cell 300 extends from the fuel manifold 200. Specifically, each fuel cell 300 extends upward (in the 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 in the longitudinal direction (x-axis direction) of each fuel cell 300 can be about 100 to 300 mm.

The proximal end 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 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 the gap between the fuel 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 total volume (crystallinity) is 60% or more, and the ratio of “volume occupied by amorphous phase and impurities” to total volume is less than 40% It is a glass of 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 distance between two adjacent fuel cells 300 is not particularly limited, but may be about 1 to 5 mm. Two adjacent fuel cells 300 are electrically connected by a current collecting member 310. A plurality of fuel cells 300 are connected by a current collecting member 310 to form a cell stack. The configuration of the current collecting member 310 will be described later.

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

[Support substrate]
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 passage 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 cell 300 is attached to the fuel manifold 200, it means the side closer to the fuel manifold 200. 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 side, and the upper side is the distal 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) It may be made of MgO (magnesium oxide) and MgAl ₂ O ₄ (magnesia alumina spinel). 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 generation element unit 10 is formed on both main surfaces of the support substrate 20, but may be formed only on one main surface. The respective power generation element units 10 are spaced apart from each other 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 type fuel cell. The power generation element units 10 adjacent in the longitudinal direction are electrically connected to each other by the 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 prevention 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. In detail, the anode collecting portion 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. In the second recess 411, the fuel electrode active portion 42 is disposed. Further, in the third recess 412, the interconnector 31 is disposed.

  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 collector 41 may be made 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 electron conductivity. The fuel electrode active portion 42 has a larger content of the substance having oxygen ion conductivity than the fuel electrode current collector 41. Specifically, in the fuel electrode active portion 42, the volume ratio of the substance having oxygen ion conductivity to the total volume excluding the pores is equal to the oxygen ion conductivity to the total volume excluding the pores in the anode 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 anode active portion 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 next interconnector 31. That is, in the longitudinal direction (x-axis direction) of the support substrate 20, the electrolytes 5 and the interconnectors 31 are alternately and continuously arranged. The electrolyte 5 is configured to cover the first and second main surfaces of the support substrate 20.

  The electrolyte 5 is a sintered body composed of a dense material having ion conductivity and no electron conductivity. The electrolyte 5 can be made of, for example, YSZ (8YSZ) (yttria stabilized zirconia). Alternatively, the electrolyte 5 may be made of 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 prevention film 7 is disposed between the electrolyte 5 and the cathode active portion 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. Provided in

The reaction prevention film 7 is made of a material containing ceria containing a rare earth element. The reaction prevention film 7 may 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 sintered 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 has an air electrode active portion 61 and an air electrode current collecting portion 62.

  The cathode active portion 61 is disposed on the reaction prevention film 7. The cathode active portion 61 has oxygen ion conductivity and electron conductivity. The content ratio of the substance having oxygen ion conductivity is larger in the cathode active part 61 than in the cathode collection 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 cathode active part 61 may be made of, for example, LSCF = (La, Sr) (Co, Fe) O ₃ (lanthanum strontium cobalt ferrite). Alternatively, the cathode active portion 61 may be formed of 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 cathode active portion 61 may be constituted 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 collector portion 62 is disposed on the air electrode active portion 61. Further, the air electrode current collecting portion 62 extends from the air electrode active portion 61 toward the adjacent power generating element portion. The anode current collector 41 and the cathode current collector 62 extend from the power generation region to opposite sides. The power generation area is an area where the fuel electrode active portion 42, the electrolyte 5 and the air electrode active portion 61 overlap.

  The air current collecting portion 62 is a fired body made of a porous material having electron 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 configured of LSC = (La, Sr) CoO ₃ (lanthanum strontium cobaltite). Alternatively, the air electrode current collector 62 may be made of Ag (silver) or 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 generation element units 10 adjacent in the longitudinal direction (x-axis direction) of the support substrate 20. In detail, the air electrode current collector portion 62 of one power generation element portion 10 extends toward the other power generation element portion 10. Further, the fuel electrode collector portion 41 of the other power generation element portion 10 extends toward the one power generation element portion 10. The interconnector 31 electrically connects the air electrode current collector portion 62 of one power generation element portion 10 and the fuel electrode current collector portion 41 of the other power generation element portion 10. The interconnector 31 is disposed in the third recess 412 of the fuel electrode 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 electron 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]
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 310. The current collecting member 310 is disposed between the first fuel cell 300a and the second fuel cell 300b. The current collecting member 310 is disposed closer to the base end side than the base end side power generating element portion 10 a disposed closest to the base end side among the plurality of power generating element portions 10 disposed on both main surfaces of the support substrate 20. Yes.

  The current collection member 310 is joined to the base end side of each of the first fuel cell 300a and the second fuel cell 300b. Specifically, the current collecting member 310 is connected to the electrical connection part 110 extending from the base-end-side 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 an air current collecting portion 62 extending from the end side power generating element portion 10a. The first fuel cell 300a, the conductive bonding material 102, and the current collecting member 310 constitute an electrochemical cell assembly.

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

  FIG. 7 is a perspective view of the current collecting member 310. FIG. 7 shows a state in which the current collecting member 310 is joined to the first fuel cell 300a. Although the second fuel cell 300b is omitted in FIG. 7, the second fuel cell 300b is actually disposed to face the first fuel cell 300a.

  The current collecting member 310 has a plate shape. For example, the current collecting member 310 can be configured of a bent metal plate (for example, a stainless steel plate). The current collecting member 310 includes a first joint 311, a second joint 312, a first connecting portion 313, and a second connecting portion 314.

  The first bonding portion 311 is bonded to the first fuel cell 300a. Specifically, the first joint portion 311 is joined to the electrical connection portion 110 extending from the base-end power generation element portion 10a (see FIG. 6) of the first fuel cell 300a by the conductive joint material 102. The electrical connection portion 110 has a first connection portion 111 and a second connection portion 112. The 1st connection part 111 can be set as the structure and material similar to the interconnector 31 mentioned above. In addition, the second connection portion 112 can be made of the same material as that of 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.

  The 1st junction part 311 is formed in flat form. In the present embodiment, the first joint portion 311 is formed in a rectangular shape extending in the width direction, but the shape of the first joint portion 311 is not particularly limited, and is a triangle or more polygon, circle, ellipse, or Other complicated shapes may be used.

  A plurality of first through holes 315 are formed in the first bonding portion 311. Each first through hole 315 is filled with the conductive bonding material 102. Thus, the bonding strength of the first bonding portion 311 to the first fuel cell 300a can be improved. The conductive bonding material 102 may protrude outward from each of the first through holes 315, and may further spread on the outer surface of the first bonding portion 311.

  In the present embodiment, each first through-hole 315 is formed in a rectangular shape extending along the width direction, but the shape of each first through-hole 315 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 first through holes 315 are provided, but the number and position of the first through holes 315 can be changed as appropriate.

  The second bonding portion 312 is electrically connected to the first bonding portion 311. The second joint portion 312 is joined to the second fuel cell 300b. Specifically, the second joint portion 312 is joined to the air electrode current collector 62 extending from the proximal power generation element portion 10a (see FIG. 6) of the second fuel cell 300b by the conductive joint material 102. The second bonding portion 312 faces the first bonding portion 311 in the arrangement direction.

  The second bonding portion 312 is formed in a flat plate shape. In the present embodiment, the second joint portion 312 has the same shape as the first joint portion 311, but may have a different shape from the first joint portion 311. There is no restriction | limiting in particular in the shape of the 2nd junction part 312, The polygon more than a triangle, circular, an ellipse, or complicated shapes other than these may be sufficient.

  A plurality of second through holes 316 are formed in the second joint portion 312. Each second through hole 316 is filled with a conductive bonding material 102. Thus, the bonding strength of the second bonding portion 312 to the second fuel cell 300b can be improved. The conductive bonding material 102 may protrude outward from each second through hole 316, and may further spread on the outer surface of the second bonding portion 312.

  In the present embodiment, each second through-hole 316 is formed in a rectangular shape extending along the width direction, but there is no particular limitation on the shape of each second through-hole 316, and it is circular, elliptical, triangular or more It may be a polygon or a complex shape other than these. In the present embodiment, three second through holes 316 are provided, but the number and position of the second through holes 316 can be changed as appropriate.

  The first and second connection parts 313 and 314 are connected to the first bonding part 311 and the second bonding part 312, respectively. In the present embodiment, the first and second connection parts 313 and 314 are respectively curved, but the present invention is not limited to this. Each of the first and second connecting portions 313 and 314 may have a flat plate shape, or may be bent at at least one location.

  In the present embodiment, the first and second connecting portions 313 and 314 are disposed at both ends of the current collecting member 310, but the positions of the first and second connecting portions 313 and 314 are not particularly limited.

[Cross-sectional shape of joint]
FIG. 8 is an enlarged view of the AA cross section of FIG. In FIG. 8, a cross-sectional view of a portion between the adjacent first through holes 315 in the first bonding portion 311 is shown.

  The first joint portion 311 of the current collection member 310 has a first main surface Sa1, a second main surface Sa2, and a pair of side surfaces Sa3. The first bonding portion 311 corresponds to the main body portion of the present invention. The thickness of the first bonding portion 311 is, for example, about 0.1 to 2.0 mm.

  The first main surface Sa1 of the first bonding portion 311 faces the first fuel cell 300a. The first main surface Sa1 of the first bonding portion 311 is bonded to the first fuel cell 300a via the conductive bonding material 102.

  The second major surface Sa2 faces the side opposite to the first major surface Sa1. That is, the second main surface Sa2 faces the space between the first fuel cell 300a and the second fuel cell 300b. In addition, when flowing oxidant gas, such as air, on the outer surface of the fuel cell 300, such as between the first fuel cell 300a and the second fuel cell 300b, the oxidant gas of the second main surface Sa2 It faces the flowing space.

  The area of the second major surface Sa is smaller than the area of the first major surface Sa1. For example, the area of the second main surface Sa2 can be about 50.00 to 99.99% of the area of the first main surface Sa1. Here, as shown in FIG. 9, the area of the first main surface Sa1 or the second main surface Sa2 means an area in a portion (shaded portion in FIG. 9) surrounded by a pair of side surfaces Sa3. Further, the ratio of the area of the second main surface Sa2 to the area of the first main surface Sa1 can be determined, for example, as follows. First, the first main surface Sa1 and the second main surface as shown in FIG. 10 are respectively divided into 10 parts along the direction (y-axis direction) in which the side surface Sa3 extends in the portion surrounded by the pair of side surfaces Sa3. A cross section (xz cross section) orthogonal to the plane Sa2 is created. In each of the nine cross sections, the length L1 of the first main surface Sa1 and the length L2 of the second main surface Sa2 are measured. The ratio of the average value of the length L2 of the second main surface Sa2 to the average value of the lengths L1 of the first main surface Sa1 is the ratio of the area of the second main surface Sa2 to the area of the first main surface Sa1. A percentage.

  The pair of side surfaces Sa3 is a surface extending in the thickness direction (z-axis direction) of the first bonding portion 311. Each side surface Sa3 extends between the first main surface Sa1 and the second main surface Sa2. Each side surface Sa3 is inclined so as to approach each other toward the second main surface Sa2. For example, an angle α between the side surface Sa3 and the first main surface Sa1 can be approximately 45.0 to 89.9 degrees. Thus, the cross-sectional shape of the first bonding portion 311 surrounded by the first main surface Sa1, the second main surface Sa2, and the pair of side surfaces Sa3 is trapezoidal.

  An angle β between the side surface Sa3 and the second main surface Sa2 is an obtuse angle. Specifically, an angle β between the side surface Sa3 and the second main surface Sa2 can be about 90.1 to 135.0 degrees. Note that the side surface Sa3 illustrated in FIG. 8 is an inner wall surface that defines the first through hole 315.

  In addition, the measurement method of the angle α and the angle β can be obtained, for example, from the cross section acquired when obtaining the ratio of the area of the second main surface Sa2 to the area of the first main surface Sa1 described above. Specifically, in each cross section, a straight line is obtained by approximating the first main surface Sa1 and the side surface Sa3 by the least square method, and the average value of the angles formed by the respective straight lines is taken as the angle α. Similarly, in each cross section, a straight line is obtained by approximating the second main surface Sa2 and the side surface Sa3 by the least square method, and the average value of the angles formed by the respective straight lines is taken as the angle β.

  The side surface Sa3 has a first region R1 and a second region R2. The first region R1 is a region on the first main surface Sa1 side of the side surface Sa3. That is, the first region R1 is a region on the first fuel cell 300a side in the side surface Sa3. Although not particularly limited, for example, the first region R1 occupies a range of about 10 to 90% of the side surface Sa3.

  The second region R2 is a region on the second main surface Sa2 side of the side surface Sa3. That is, the second region R2 is a region on the side of the side surface Sa3 away from the first fuel cell 300a. Although not particularly limited, for example, the second region R2 occupies about 10 to 90% of the side surface Sa3.

  The first joint portion 311 is made of an alloy material containing Cr (chromium). As such a metal material, Fe-Cr alloy steel (stainless steel etc.), Ni-Cr alloy steel, etc. can be used. The content ratio of Cr in the first bonding portion 311 is not particularly limited, but can be 4 to 30% by mass.

The first bonding portion 311 may contain Ti (titanium) or Al (aluminum). The Ti content in the first joint portion 311 is not particularly limited, but is 0.01 to 1.0 at. %. The Al content in the first joint 311 is not particularly limited, but is 0.01 to 0.4 at. %. The first bonding portion 311 may contain Ti as TiO ₂ (titania) or Al as Al ₂ O ₃ (alumina).

  In addition, the 2nd junction part 312, the 1st connection part 313, and the 2nd connection part 314 can also be comprised with the material similar to the 1st junction part 311.

  The current collecting member 310 has a coating layer 317. The covering layer 317 covers the first joint portion 311, the second joint portion 312, the first connection portion 313, and the second connection portion 314. As described above, the covering layer 317 covers the first joint portion 311, the second joint portion 312, the first connection portion 313, and the second connection portion 314, thereby suppressing the volatilization of Cr therefrom. As a result, Cr poisoning at the air electrode 6 of each fuel cell 300 is suppressed.

  Specifically, the covering layer 317 is formed on the first main surface Sa1, the second main surface Sa2, and the side surface Sa3 of the first joint portion 311. The thickness of the covering layer 317 is not particularly limited, but can be, for example, 1.0 to 200 μm.

  On the side surface Sa3, the thickness of the covering layer 317 in the first region R1 and the thickness of the covering layer 317 in the second region R2 may be different from each other. For example, the thickness of the covering layer 317 in the second region R2 is thicker than the thickness of the covering layer 317 in the first region R1. In this case, the thickness of the covering layer 317 in the second region R2 can be about 1.1 to 200 μm, and the thickness of the covering layer 317 in the first region R1 can be about 1.0 to 100 μm. The ratio of the thickness of the coating layer 317 in the second region R2 to the thickness of the coating layer 317 in the first region R1 can be about 1.1 to 50. Note that the thickness of the coating layer 317 can be adjusted to be greater than the thickness in the first region R1, for example, by adjusting the thickness when the coating layer forming slurry is applied. it can.

  The thickness of the coating layer 317 in the first region R1 can be measured as follows. First, after the first bonding portion 311 is filled with resin, mechanical polishing is performed in parallel with the first main surface Sa1. Specifically, the polishing is performed from the first main surface Sa1 side in three steps of 2.5% (T / 40) of the thickness T of the first joint portion 311. Then, every three polishings, the thickness of the coating layer 317 is measured at any 10 locations by image processing from the cross-sectional shape obtained by SEM observation. Then, the average value of the thickness of the covering layer 317 in total of 30 points is taken as the thickness of the covering layer 317 in the first region R1.

  The thickness of the covering layer 317 in the second region R2 can be measured as follows. First, after the first bonding portion 311 is filled with resin, mechanical polishing is performed in parallel with the second main surface Sa2. More specifically, the polishing is performed from the second main surface Sa2 side in three steps of 2.5% (T / 40) of the thickness T of the first joint 311. Then, every three polishings, the thickness of the coating layer 317 is measured at any 10 locations by image processing from the cross-sectional shape obtained by SEM observation. Then, the average value of the thickness of the covering layer 317 in total of 30 points is taken as the thickness of the covering layer 317 in the second region R2.

  As a material for forming the covering layer 317, a ceramic material can be used. The specific type of ceramic material can be appropriately selected according to the application site. In the present embodiment, since the current collecting member 310 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 covering layer 317 only needs to suppress the volatilization of Cr, and the constituent material thereof is not limited to the ceramic material.

  The conductive bonding material 102 covers the entire first main surface Sa1 of the first bonding portion 311 and the side surface Sa3 via the coating layer 317. The conductive bonding material 102 mainly covers the first region R1 of the side surface Sa3 via the covering layer 317. The conductive bonding material 102 covers only a part of the side surface Sa3 on the second region R2 side. Alternatively, the conductive bonding material 102 does not cover the second region R2.

  The configuration of the first joint portion 311 of the current collecting member 310 has been described above, but this configuration is preferably applied to the second joint portion 312 of the current collector member 310.

(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 embodiment, the current collecting member 310, which is an embodiment of the metal member for an electrochemical cell according to the present invention, is applied to a horizontally striped fuel cell, but also to a so-called vertically striped fuel cell or the like. Can be applied. The vertically-striped fuel cell unit includes a conductive support substrate, a power generation unit (fuel electrode, solid electrolyte layer, and air electrode) disposed on one main surface of the support substrate, and the other 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 first and second joint portions 311 and 312 are connected by the first and second connection portions 313 and 314, but the present invention is not limited to this. The current collecting member 310 only needs to have the first and second joint portions 311 and 312 that are electrically connected, and the connecting means of the first and second joint portions 311 and 312 is not limited. For example, the 1st and 2nd junction parts 311 and 312 may be connected by three or more connection parts, and may be connected by one connection part.

Modification 3
The first joint portion 311 may not have the first through hole 315. In this case, the side surface Sa3 of the first bonding portion 311 is a side surface that constitutes the outer edge of the first bonding portion 311. Similarly, the second joint portion 312 may not have the second through hole 316.

Modification 4
The current collecting member 310 may further include an oxide film. For example, it is preferable that the first bonding portion 311 be covered with an oxide film, and a covering layer cover the oxide film. For example, the first bonding portion 311 is covered with a chromium oxide film. The chromium oxide film is composed of chromium oxide. The thickness of the chromium oxide film is not particularly limited, but can be, for example, 0.5 to 10 μm. In this case, the covering layer 317 is formed on the chromium oxide film.

Modification 5
The metal member for an electrochemical cell of the present invention is not limited to the current collecting member 310. For example, the metal member for an electrochemical cell of the present invention may be an end portion current collecting member for extracting an electric current from a fuel cell disposed at an end portion in the arrangement direction.

Modification 6
As shown in FIG. 11, the thickness of the coating layer 317 in the first region R1 may be configured to be thicker than the thickness of the coating layer 317 in the second region R2. In this case, the thickness of the coating layer 317 in the first region R1 can be about 1.1 to 200 μm, and the thickness of the coating layer 317 in the second region R2 can be about 1.0 to 100 μm. The ratio of the thickness of the covering layer 317 in the first region R1 to the thickness of the covering layer 317 in the second region R2 can be about 1.1 to 50.

Modification 7
In the side surface Sa3 of the first bonding portion 311, the surface roughness in the second region R2 can be larger than the surface roughness in the first region R1. In detail, the arithmetic mean roughness in the second region R2 can be larger than the arithmetic mean roughness in the first region R1. According to this configuration, on the side surface Sa3, the covering layer 317 tends to be formed more intensively in the second region Sa2 than in the first region Sa1.

  For example, the arithmetic average roughness in the second region R2 can be made larger than the arithmetic average roughness in the first region R1 by blasting. Specifically, as shown in FIG. 12, the second main surface Sa2 of the first joint portion 311 is masked, and the abrasive is struck from obliquely above with the second main surface Sa2 side facing up. The arrows in FIG. 12 indicate the discharge direction of the abrasive. By this blasting, the arithmetic mean roughness in the second region R2 can be made larger than the arithmetic mean roughness in the first region R1. In addition, although not particularly limited, the surface roughness in the second region R2 of the side surface Sa3 is larger than the surface roughness of the first and second main surfaces Sa1, Sa2.

  For example, the arithmetic average roughness in the second region R2 is about 0.12 to 10 μm, and the arithmetic average roughness in the first region R1 is about 0.10 to 2.0 μm. Moreover, it is preferable that the ratio of the arithmetic mean roughness in 2nd area | region R2 with respect to the arithmetic mean roughness in 1st area | region R1 shall be about 1.2-30.

  The surface roughness of the first region R1 can be measured as follows. First, after the first bonding portion 311 is filled with resin, mechanical polishing is performed in parallel with the first main surface Sa1. Specifically, the polishing is performed from the first main surface Sa1 side in three steps of 2.5% (T / 40) of the thickness T of the first joint portion 311. The surface roughness (arithmetic mean roughness) in the first region R1 is measured by image processing from the cross-sectional shape obtained by SEM observation every three polishings. And the value which averaged these three surface roughness (arithmetic mean roughness) can be made into surface roughness of 1st field R1.

  In addition, the surface roughness of the second region R2 can be measured as follows. First, after the first bonding portion 311 is filled with resin, mechanical polishing is performed in parallel with the second main surface Sa2. More specifically, the polishing is performed from the second main surface Sa2 side in three steps of 2.5% (T / 40) of the thickness T of the first joint 311. The surface roughness (arithmetic average roughness) in the second region R2 is measured by image processing from the cross-sectional shape obtained by SEM observation every three polishings. And the value which averaged these three surface roughness (arithmetic mean roughness) can be made into surface roughness of 2nd field R2.

Modification 8
FIG. 13 is an enlarged view of the side surface Sa3 of the first joint portion 311. FIG. As shown in FIG. 13, the first bonding portion 311 has a step portion 318 formed between the first region R1 and the second region R2. The stepped portion 318 faces in the direction (upper direction in FIG. 13) in which the second main surface Sa2 faces. In this case, the side surface Sa3 may or may not be inclined so as to approach each other toward the second main surface Sa2.

  The step portion 318 is, for example, a step (dimension in the x-axis direction) of about 1 to 400 μm. The step portion 318 may extend continuously in the direction in which the side surface Sa3 extends (y-axis direction) or may be formed intermittently. The stepped portion 318 can be formed, for example, by press working with a die provided with a desired stepped shape.

  As shown in FIG. 14, the step portion 318 may be configured such that the first region R1 and the second region R2 overlap each other on the side surface Sa. Specifically, when the side surface Sa3 is viewed along the direction (x-axis direction) orthogonal to the side surface Sa3, the end portion R11 on the second main surface Sa2 side of the first region R1 and the first portion of the second region R2 The step portion 318 is configured such that the end portion R21 on the main surface Sa1 side overlaps with each other.

102: Conductive bonding material 300: Fuel cell 310: Current collecting member 311: First bonding portion 317: Coating layer R1: First region R2: Second region Sa1: First main surface Sa2: Second main surface Sa3: side

Claims (11)

A metal member joined to a pair of electrochemical cells,
First main surface facing one of said electrochemical cell, a first joint portion having a second major surface, and a pair of side surfaces opposite to the first main surface,
A first main surface facing the other electrochemical cell side, a second main surface opposite to the first main surface, and a second joint portion having a pair of side surfaces;
A coating layer covering the first and second joints ;
Equipped with
The area of the second major surface of the first junction, rather smaller than the area of the first main surface of the first joint portion,
The area of the second main surface of the second bonding portion is smaller than the area of the first main surface of the second bonding portion.
Metal parts for electrochemical cells.
The pair of side surfaces are inclined toward each other toward the second main surface,
The metal member for electrochemical cells according to claim 1.
The angle between the second main surface and at least one of the side surfaces is an obtuse angle,
The metal member for an electrochemical cell according to claim 1 or 2.
The side surface has a first region on the first main surface side and a second region on the second main surface side.
The metal member for electrochemical cells according to any one of claims 1 to 3.
The thickness of the covering layer in the second region is thicker than the thickness of the covering layer in the first region,
The metal member for electrochemical cells of Claim 4.
The thickness of the covering layer in the first region is thicker than the thickness of the covering layer in the second region,
The metal member for electrochemical cells of Claim 4.
The surface roughness in the second region is greater than the surface roughness in the first region,
The metal member for an electrochemical cell according to any one of claims 4 to 6.
The side surface has a stepped portion formed between the first region and the second region.
The metal member for electrochemical cells according to any one of claims 4 to 7.
The body portion has a through hole,
The side surface constitutes an inner wall surface of the through hole,
The metal member for electrochemical cells according to any one of claims 1 to 8.
A pair of electrochemical cells,
The first main surface of the first joint portion is disposed toward one of the electrochemical cells , and the first main surface of the second joint portion is disposed toward the other electrochemical cell. The metal member for an electrochemical cell according to any one of 9,
A conductive bonding material for bonding the metal member to the electrochemical cell;
An electrochemical cell assembly comprising:
  A metal member joined to an electrochemical cell,
  A main body having a first main surface facing the electrochemical cell side, a second main surface opposite to the first main surface, and a pair of side surfaces;
  A coating layer covering the body portion;
Equipped with
  The area of the second main surface is smaller than the area of the first main surface
  The side surface includes a first region on the first main surface side and a second region on the second main surface side,
  The surface roughness in the second region is greater than the surface roughness in the first region,
Metal parts for electrochemical cells.

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