JP6507290B1 - Metal member for electrochemical cell, and electrochemical cell assembly using the same - Google Patents

Abstract

[Object] To suppress oxidation in a region on a second main surface side of a side surface of a metal member when an oxidant gas is supplied to the outer surface of an electrochemical cell. An electrochemical cell metal member (310) includes a main body (311) and a covering layer (317). The main body portion 311 has a first main surface Sa1, a second main surface Sa2, and a side surface Sa3. The first major surface Sa1 faces the electrochemical cell 300a. 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 side surface Sa3 has a first region R1 on the side of the first main surface Sa1 and a second region R2 on the side of the second main surface Sa2. The surface roughness in the second region R2 is larger than the surface roughness in the first region R1. [Selected figure] 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, a cell stack using a fuel cell, which is a type of electrochemical cell, has attracted attention 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 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 an oxidant gas such as air is supplied to the outer surface of the fuel cell, the region on the second major surface side of the side surface of the current collector is exposed to the oxidant gas compared to the region on the first major surface May be easily oxidized. Then, when oxidizing agent gas is supplied to the outer surface of an electrochemical cell, let it be a subject to suppress the oxidation in the area | region at the side of the 2nd main surface among the side surfaces of a metal member.

  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 side surface. The first major surface faces the electrochemical cell. The second main surface is the main surface opposite to the first main surface. The covering layer covers the main body. The side surface has 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 larger than the surface roughness in the first region.

  According to this configuration, of the side surfaces of the metal member, the surface roughness in the second region is larger than the surface roughness in the first region. For this reason, the cover layer is likely to be formed more preferentially in the second region than in the first region among the side surfaces of the metal member. As a result, since the second region is reliably covered by the covering layer, the oxidation in the second region can be suppressed even if the oxidant gas is supplied to the outer surface of the electrochemical cell. In particular, the side surface tends to be difficult to form a covering layer because the area is smaller than the first and second main surfaces, but the above-described configuration can more reliably suppress oxidation in the second region. .

  Preferably, the thickness of the covering layer in the second region is thicker than the thickness of the covering layer in the first region. With such a configuration, oxidation can be further suppressed in a region easily exposed to the oxidant gas.

  Preferably, the thickness of the covering layer in the first region is thicker than the thickness of the covering layer in the second region. With this configuration, the following effects can be obtained in the case where the main body is a metal containing chromium. That is, by further suppressing the volatilization of chromium from the main body in the region closer to the electrochemical cell, chromium poisoning in the electrochemical cell can be further suppressed.

  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 major 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, when the oxidizing gas is supplied to the outer surface of the electrochemical cell, it is possible to suppress the oxidation in the region on the second main surface side among the side surfaces of the metal member.

The perspective view of a cell stack device. Sectional drawing of a cell stack apparatus. FIG. 2 is a perspective view of a fuel manifold. FIG. 2 is a perspective view of a fuel cell. Sectional drawing of a fuel cell. Sectional drawing of the proximal end side of a fuel cell. The perspective view of a current collection member. AA sectional drawing of FIG. Sectional drawing which shows an example of a manufacturing method. Sectional drawing of the current collection member 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. 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 the 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 Such crystallized glass, for _example, SiO 2 _-B 2 _{O 3 system,} SiO 2 -CaO-based, or _SiO 2 -MgO systems.

  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. The two adjacent fuel cells 300 are electrically connected by the current collecting member 310. A cell stack is formed by connecting a plurality of fuel cells 300 with a current collecting member 310. 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.

[Supporting substrate]
As shown in FIG. 4, the support substrate 20 internally has a plurality of gas flow paths 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. The respective gas channels 21 extend substantially parallel to one another. The term “proximal side” means the gas supply side of the gas flow channel. Specifically, when the fuel cell 300 is attached to the fuel manifold 200, it means the side closer to the fuel manifold 200. Moreover, a front end side means the opposite side to the gas supply side of a 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 spaced apart from each other in the longitudinal direction of the support substrate 20.

The support substrate 20 is made of a porous material having no electron 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 sintered body composed of a porous material having electron conductivity. The fuel electrode 4 has a fuel electrode current collector 41 and a fuel electrode active unit 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 collector 41 has electron conductivity. It is preferable that the fuel electrode current collecting unit 41 have electron conductivity higher than that of the fuel electrode active unit 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) It is 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 sex.

  The fuel electrode active portion 42 can be made of, for example, NiO (nickel oxide) and YSZ (8 YSZ) (yttria stabilized zirconia). Alternatively, the anode 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 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.

[Reactive film]
The reaction prevention film 7 is a sintered 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 the occurrence of a phenomenon in which a reaction layer having a large electric resistance is formed at the interface between the electrolyte 5 and the air electrode 6 by the reaction between YSZ in the electrolyte 5 and Sr in 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 prevention film 7 is, for example, about 3 to 50 μm.

[Air pole]
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, in the cathode active part 61, the volume ratio of the substance having oxygen ion conductivity to the total volume excluding the pores is equal to the oxygen ion conduction to the total volume excluding the pores in the cathode current collecting part 62. It is larger than the volume ratio of the substance having sex.

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) etc. may be comprised. 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 cathode active portion 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. It is preferable that the air electrode current collecting portion 62 have electron conductivity higher than that of the air electrode active portion 61. The air electrode current collector 62 may or may not have oxygen ion conductivity.

The air electrode current collector 62 may 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 current collecting portion 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 (a first fuel cell 300 a and a 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. Of the plurality of power generation element units 10 disposed on both main surfaces of the support substrate 20, the current collection member 310 is disposed on the more proximal side than the proximal end power generation element unit 10a disposed on the most proximal side. There is.

  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. In detail, the current collecting member 310 includes an electrical connection portion 110 extending from the proximal end power generating element portion 10a of the first fuel cell 300a via the conductive bonding material 102, and a base of the second fuel cell 300b. It is joined to the air electrode current collection part 62 extended from the end side electric power generation element part 10a. The first fuel cell 300 a, 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.

  FIG. 7 is a perspective view of the current collecting member 310. FIG. 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 collection member 310 is plate-shaped. 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 bonding portion 311 is bonded by the conductive bonding material 102 to the electrical connection portion 110 extending from the proximal end power generating element portion 10a (see FIG. 6) of the first fuel cell 300a. The electrical connection portion 110 has a first connection portion 111 and a second connection portion 112. The first connection portion 111 can have the same configuration and material as the interconnector 31 described 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 first bonding portion 311 is formed in a flat plate shape. In the present embodiment, the first bonding portion 311 is formed in a rectangular shape extending in the width direction, but the shape of the first bonding portion 311 is not particularly limited, and may be a polygon having a triangle or more, a circle, an ellipse, or Complex shapes other than these 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 circular, elliptical, triangular or more. It may be a polygon or a complex shape other than these. Further, in the present embodiment, the 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 bonding portion 312 is bonded by the conductive bonding material 102 to the air electrode current collecting portion 62 extending from the proximal end power generating element portion 10 a (see FIG. 6) of the second fuel cell 300 b. 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 bonding portion 312 has the same shape as the first bonding portion 311, but may have a shape different from that of the first bonding portion 311. There is no restriction | limiting in particular in the shape of the 2nd junction part 312, A polygon more than a triangle, a circle, an ellipse, or complex 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 the shape of each second through hole 316 is not particularly limited, and may be circular, elliptical, triangular or more. It may be a polygon or a complex shape other than these. Further, 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. The first and second connection parts 313 and 314 may be flat or may be bent at at least one place.

  Furthermore, in the present embodiment, the first and second connection parts 313 and 314 are disposed at both ends of the current collection member 310, but the positions of the first and second connection parts 313 and 314 are not particularly limited.

[Cross-sectional shape of joint]
FIG. 8 is an enlarged view of an A-A cross section of FIG. 7. 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 side surface 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 I'm facing a flowing space.

  The side surface Sa3 is a surface extending in the thickness direction (z-axis direction) of the first bonding portion 311. The side surface Sa3 extends between the first main surface Sa1 and the second main surface Sa2. The side surface Sa3 shown in FIG. 8 is an inner wall surface that defines the first through hole 315.

  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 side of the first fuel battery cell 300a 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.

  In the second region R2, a plurality of asperities are formed on the side surface Sa3. For example, the plurality of asperities are arranged along the direction in which the first and second main surfaces Sa1 and Sa2 extend (y-axis direction or x-axis direction).

  The surface roughness of the side surface Sa3 is different between the first region R1 and the second region R2. The surface roughness in the second region R2 is larger than the surface roughness in the first region R1. In detail, the arithmetic mean roughness in the second region R2 is larger than the arithmetic mean roughness in the first region R1.

  For example, by blasting, the arithmetic average roughness in the second region R2 can be made larger than the arithmetic average roughness in the first region R1. Specifically, as shown in FIG. 9, the second main surface Sa2 of the first bonding portion 311 is masked, and an abrasive is applied obliquely from above with the second main surface Sa2 side up. The arrows in FIG. 9 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. In detail, 2.5% (T / 40) of thickness T of the 1st joined part 311 is divided into 3 times, and it grinds from the 1st principal surface Sa1 side. And surface roughness (arithmetic mean roughness) in 1st area | region R1 is measured by image processing from the cross-sectional shape obtained by carrying out SEM observation for every 3 times of grinding | polishing. 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. In detail, 2.5% (T / 40) of thickness T of the 1st joined part 311 is divided into 3 times, and it grinds from the 2nd principal surface Sa2 side. And surface roughness (arithmetic mean roughness) in 2nd area | region R2 is measured by image processing from the cross-sectional shape obtained by carrying out SEM observation for every grinding | polishing of 3 times. And the value which averaged these three surface roughness (arithmetic mean roughness) can be made into surface roughness of 2nd field R2.

  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 content ratio of Ti in the first bonding portion 311 is not particularly limited, but the content ratio of 0.01 to 1.0 at. It can be%. Although the content ratio of Al in the first bonding portion 311 is not particularly limited, the content ratio of 0.01 to 0.4 at. It can be%. The first bonding portion 311 may contain Ti as TiO ₂ (titania) or Al as Al ₂ O ₃ (alumina).

  The second bonding portion 312, the first connecting portion 313, and the second connecting portion 314 can also be made of the same material as the first bonding portion 311.

  The current collecting member 310 has a covering layer 317. The covering layer 317 covers the first bonding portion 311, the second bonding portion 312, the first connecting portion 313, and the second connecting portion 314. By covering the first bonding portion 311, the second bonding portion 312, the first connecting portion 313, and the second connecting portion 314 in this manner, the volatilization of Cr from these can be suppressed. As a result, Cr poisoning at the air electrode 6 of each fuel cell 300 is suppressed.

  In detail, 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 bonding portion 311. The thickness of the covering layer 317 is not particularly limited, but can be, for example, 1.0 to 200 μm.

  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 on the side surface Sa3. 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 covering layer 317 in the second region R2 to the thickness of the covering layer 317 in the first region R1 can be about 1.1 to 50. The thickness of the covering layer 317 may be adjusted to a thickness in the second region R2 thicker than that in the first region R1 by, for example, adjusting a thickness at the time of applying the slurry for forming a covering layer. it can.

  The thickness of the covering layer 317 in the first region R1 can be measured from the cross-sectional shape used when measuring the surface roughness in the first region R1 described above. Specifically, in each cross-sectional shape, the thickness of the covering layer 317 is measured at any ten places. 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 from the cross-sectional shape used when measuring the surface roughness in the second region R2 described above. Specifically, in each cross-sectional shape, the thickness of the covering layer 317 is measured at any ten places. 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 this embodiment, since the current collecting member 310 is required to have conductivity, the ceramic material is made of a perovskite type complex oxide containing La and Sr, and transition metals such as Mn, Co, Ni, Fe, and Cu. Spinel type composite 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 also covers the side surface Sa3 via the covering 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.

  As mentioned above, although the structure of the 1st joined part 311 of current collection member 310 was explained, it is preferred to apply also to the 2nd joined part 312 of current collection 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. It can apply. 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. And an interconnector. In addition to the fuel cell, the metal member for an electrochemical cell according to the present invention is applicable to a solid oxide electrochemical cell including a solid oxide electrolytic 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 collection member 310 may have the first and second junctions 311 and 312 electrically connected, and the connection means of the first and second junctions 311 and 312 is not limited. For example, the first and second joints 311 and 312 may be connected by three or more connection parts, or 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 collection member 310 may further have 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. 10, the thickness of the covering layer 317 in the first region R1 may be configured to be thicker than the thickness of the covering layer 317 in the second region R2. In this case, the thickness of the covering layer 317 in the first region R1 can be about 1.1 to 200 μm, and the thickness of the covering 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.

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 (6)

A metal member joined to the electrochemical cell, wherein
A main portion having a first main surface facing the electrochemical cell side, a second main surface opposite to the first main surface, and side surfaces;
A covering layer covering the main body;
Equipped with
The side surface has 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 members for electrochemical cells.
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 according to claim 1.
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 according to claim 1.
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 3.
The surface roughness in the second region is larger than the surface roughness in the first and second main surfaces,
The metal member for electrochemical cells according to any one of claims 1 to 4.
An electrochemical cell,
The metal member for an electrochemical cell according to any one of claims 1 to 5, which is disposed with the first main surface facing the electrochemical cell.
A conductive bonding material for bonding the metal member to the electrochemical cell;
An electrochemical cell assembly comprising:

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