JP2018098186A - Cell stack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cell stack capable of controlling occurrence of cracks of a fuel battery cell.SOLUTION: A cell stack includes: first and second fuel battery cells 300a, 300b extending in the longitudinal direction; and a current collector member 301 for electrically connecting the first and second fuel battery cells 300a, 300b. The current collector member 301 includes: a flat plate-like first joint part a1 which is joined to the first fuel battery cell 300a; a flat plate-like second joint part a2 which is joined to the second fuel battery cell 300b; and curved plate-like first and second coupling parts b1, b2 which are coupled with the first joint part a1 and the second joint part a2. Each of the first and second coupling parts b1, b2 is arranged in the outside of a gap between the first joint part a1 and the second joint part a2 in the longitudinal direction.SELECTED DRAWING: Figure 7

Description

  The present invention relates to a cell stack.

  2. Description of the Related Art Conventionally, a cell stack including a plurality of fuel cells and a current collecting member that electrically connects two adjacent fuel cells is known. Patent Document 1 proposes a current collecting member in which a plurality of parallel portions and a plurality of inclined portions are alternately connected. According to the current collecting member of Patent Document 1, it is possible to suppress the occurrence of cracks in the fuel cell due to the pressing force of the current collecting member.

Japanese Patent Laying-Open No. 2015-76339

  However, since the current collecting member described in Patent Document 1 has a complicated structure, there is a demand for suppressing cracks in the fuel cell with a current collecting member having a simpler structure.

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

  The cell stack according to the present invention includes a first fuel cell extending in the longitudinal direction, a second fuel cell adjacent to the first fuel cell and extending in the longitudinal direction, and the first fuel cell and the second fuel cell. And a current collecting member that electrically connects the first fuel cell and the second fuel cell. The current collecting member includes a flat plate-like first joint portion joined to the first fuel cell, a flat plate-like second joint portion joined to the second fuel cell and facing the first joint portion, and a first A curved plate-like first coupling portion coupled to the joint portion and the second joint portion, and a curved plate-shaped second coupling portion coupled to the first joint portion and the second joint portion. Each of the first connecting portion and the second connecting portion is disposed outside the gap between the first joint portion and the second joint portion in the longitudinal direction.

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

The perspective view of a cell stack apparatus. Sectional drawing of a cell stack apparatus. The perspective view of a fuel manifold. The perspective view of a fuel cell. Sectional drawing of a fuel cell. Sectional drawing of the base end side of a fuel cell. The perspective view of a current collection member. A sectional view of FIG. The top view of a current collection member. The perspective view of a current collection member. The perspective view of a current collection member. B sectional drawing of FIG.

  Hereinafter, an embodiment of a cell stack using a current collecting member 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 fuel gas (for example, hydrogen) to each fuel cell 300. The fuel manifold 200 is hollow and has an internal space. Fuel gas is supplied to the internal space of the fuel manifold 200 through the introduction pipe 201. The fuel manifold 200 has a plurality of insertion holes 202 arranged at intervals. Each insertion hole 202 is formed in the top plate 203 of the fuel manifold 200. Each insertion hole 202 communicates with the internal space of the fuel manifold 200 and the outside.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

[Current collecting member]
As shown in FIG. 6, two adjacent fuel cells 300 (first fuel cell 300 a and second fuel cell 300 b) are electrically connected by a current collecting member 301. The current collecting member 301 is disposed between the first fuel cell 300a and the second fuel cell 300b. The current collecting member 301 is arranged closer to the base end side than the base end side power generating element part 10a arranged closest to the base end side among the plurality of power generating element parts 10 arranged on both main surfaces of the support substrate 20. Yes.

The current collecting member 301 is joined to the base end sides of the first fuel cell 300a and the second fuel cell 300b. Specifically, the current collecting member 301 includes the air electrode current collector 62 extending from the base power generation element portion 10a of the first fuel cell 300a and the base end of the second fuel cell 300b via the bonding material 102. It joins with the air electrode current collection part 62 extended from the side electric power generation element part 10a. The bonding material 102 is at least one selected from, for example, (Mn, Co) ₃ O ₄ , (La, Sr) MnO ₃ , and (La, Sr) (Co, Fe) O ₃ .

  Here, FIG. 7 is a perspective view of the current collecting member 301. FIG. 7 shows a state where the current collecting member 301 is joined to the first fuel cell 300a. In FIG. 7, the second fuel battery cell 300b is omitted, but actually, the second fuel battery cell 300b is arranged so as to face the first fuel battery cell 300a.

  The current collecting member 301 is formed by bending a rectangular metal plate (for example, a stainless steel plate). The current collecting member 301 is disposed along the width direction (y-axis direction). The current collecting member 301 is disposed inside the gap between the first fuel cell 300a and the second fuel cell 300b, and does not protrude outside the gap.

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

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

  The 1st junction part a1 is formed in flat form. In this embodiment, the 1st junction part a1 is arrange | positioned so that it may extend in the width direction. Although the 1st junction part a1 is formed in the rectangular shape, it may be formed in the ellipse, the ellipse, the triangle, the polygon more than a pentagon, or complicated shapes other than these.

  A plurality of first through holes c1 are formed in the first joint portion a1. Each first through-hole c1 is filled with a bonding material 102. Thereby, the joining force of the 1st junction part a1 with respect to the 1st fuel cell 300a can be improved. The bonding material 102 may protrude to the outside of each first through hole c1, and may further spread on the outer surface of the first bonding portion a1. In the present embodiment, each first through hole c1 is formed in a rectangular shape extending along the width direction, but is circular, elliptical, triangular, square, pentagonal or more polygonal, or other complex It may be formed in a shape. In the present embodiment, the three first through holes c1 are provided, but the number of the first through holes c1 can be appropriately changed.

  Here, FIG. 8 is a cross-sectional view of FIG. The first joint portion a1 has a first main surface Sa1. The first main surface Sa1 of the first joint a1 faces the outer surface Ta side of the first fuel cell 300a. The first main surface Sa1 of the first joint portion a1 is joined to the first fuel cell 300a via the joining material 102.

  From the viewpoint of improving the bonding strength, the ratio A2 / A1 of the area A2 of the inner wall surface Sc1 that defines the through hole c1 to the area A1 of the first bonding portion a1 viewed from the first main surface Sa1 is 0.1 or more. Preferably there is. From the viewpoint of manufacturing the first joint a1, the ratio A2 / A1 is preferably 0.7 or less. In addition, when 1st junction part a1 has several through-hole c1 like this embodiment, area A2 of inner wall surface Sc1 means the total value of the area of inner wall surface Sc1 which defines each through-hole c1. . Further, the area A1 of the first joint a1 is an area including the through hole c1. For example, when the first joint part a1 is rectangular as in the present embodiment, the area A1 of the first joint part a1 is obtained by multiplying the height of the first joint part a1 by the width of the first joint part a1. Desired.

  The second joint portion a2 is joined to the second fuel cell 300b. Specifically, the second joint portion a2 is joined by the joining material 102 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. The second joint part a2 faces the first joint part a1 in the arrangement direction.

  The 2nd junction part a2 is formed in flat form. In this embodiment, the 2nd junction part a2 is arrange | positioned so that it may extend in the width direction. The second joint a2 is formed in a rectangular shape, but may be formed in an oval, an ellipse, a triangle, a polygon having five or more corners, or a complicated shape other than these. In the present embodiment, the length of the second joint part a2 in the width direction is equal to the length of the first joint part a1 in the width direction. The width of the second joint a2 in the longitudinal direction is equal to the width of the first joint a1 in the longitudinal direction. However, the shape of the second joint portion a2 may be different from the shape of the first joint portion a1.

  A plurality of second through holes c2 are formed in the second joint portion a2. Although not shown in FIG. 7, each of the second through holes c <b> 2 is filled with the bonding material 102. Thereby, the joining force of the 2nd junction part a2 with respect to the 2nd fuel cell 300b can be improved. The bonding material 102 may protrude to the outside of each second through hole c2, and may further spread on the outer surface of the second bonding portion a2. In the present embodiment, each second through-hole c2 is formed in a rectangular shape extending in the width direction, but is circular, elliptical, triangular, square, pentagonal or more polygonal, or other complex It may be formed in a shape. Moreover, although the three 2nd through-holes c2 are provided, the number of the 2nd through-holes c2 can be changed suitably. The shape of the second through hole c2 may be the same as or different from the first through hole c1.

  The 1st connection part b1 is connected with the one end part P1 of the 1st junction part a1 in the width direction, and the one end part Q1 of the 2nd junction part a2 in the width direction. One end portion P1 of the first joint portion a1 and one end portion Q1 of the second joint portion a2 face each other in the arrangement direction.

  The first connecting part b1 is formed in a curved plate shape. That is, the first connecting portion b1 is formed to be smoothly curved as a whole. As a result, the flexibility of the current collecting member 301 can be improved, and the occurrence of cracks in the first fuel cell 300a and the second fuel cell 300b due to the pressing force from the current collecting member 301 is suppressed. it can. One end portion R1 of the first connecting portion b1 is smoothly connected to one end portion P1 of the first joint portion a1. The other end portion R2 of the first connecting portion b1 is smoothly connected to one end portion Q1 of the second joint portion a1.

  The first connecting part b1 is disposed outside the gap between the first joint part a1 and the second joint part a2 in the longitudinal direction. In this embodiment, the 1st connection part b1 is arrange | positioned at the base end side of the 1st junction part a1 and the 2nd junction part a2, and is formed in convex shape toward the base end side. Thus, since the 1st connection part b1 does not protrude to the outer side of the 1st junction part a1 and the 2nd junction part a2 in the width direction, it can suppress that the 1st connection part b1 interferes with a peripheral member. In addition, the 1st connection part b1 may be arrange | positioned at the front end side of the 1st junction part a1 and the 2nd junction part a2, and may be formed in convex shape toward the front end side.

  The second connecting portion b2 is disposed on the opposite side of the first connecting portion b1 in the width direction. By providing the second connecting portion b2 in addition to the first connecting portion b1, it is possible to suppress the current from being concentrated on one connecting portion, so that the electric power between the first fuel cell 300a and the second fuel cell 300b. Loss can be reduced.

  The second connecting portion b2 is connected to the other end portion P2 of the first joint portion a1 in the width direction and the other end portion Q2 of the second joint portion a2 in the width direction. The other end portion P2 of the first joint portion a1 and the other end portion Q2 of the second joint portion a2 face each other in the arrangement direction.

  The second connecting part b2 is formed in a curved plate shape. That is, the second connection part b2 is formed so as to be smoothly curved as a whole. As a result, the flexibility of the current collecting member 301 can be improved, and the occurrence of cracks in the first fuel cell 300a and the second fuel cell 300b due to the pressing force from the current collecting member 301 is suppressed. it can. One end S1 of the second connecting portion b2 is smoothly connected to the other end P2 of the first joint a1. The other end S2 of the second connecting part b2 is smoothly connected to the other end Q2 of the second joint part a1.

  The second connecting portion b2 is disposed outside the gap between the first joint portion a1 and the second joint portion a2 in the longitudinal direction. In this embodiment, the 2nd connection part b2 is arrange | positioned at the base end side of the 1st junction part a1 and the 2nd junction part a2, and is formed in convex shape toward the base end side. Thus, since the 2nd connection part b2 does not protrude outside the 1st joined part a1 and the 2nd joined part a2 in the width direction, it can control that the 2nd connected part b2 interferes with a peripheral member. In addition, the 1st connection part b1 may be arrange | positioned at the front end side of the 1st junction part a1 and the 2nd junction part a2, and may be formed in convex shape toward the front end side.

  Here, FIG. 9 is a plan view of the current collecting member 301 viewed from the first joint a1 side. In the width direction (y-axis direction), the length L1 of the first joint part a1 is greater than the total length L4 of the length L2 of the first connection part b1 and the length L3 of the second connection part b2.

  From the viewpoint of further improving the flexibility of the current collecting member 301 and further suppressing cracks, the ratio L4 / L1 of the total length L4 of the connecting portions b1 and b2 with respect to the length L1 of the first joint portion a1 is: It is preferable that it is 0.4 or less. The ratio L4 / L1 is preferably 0.05 or more from the viewpoint of suppressing current concentration in each of the connecting portions b1 and b2 and smoothing the flow of current between the joint portions a1 and a2.

[Modification]
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 case where the current collecting member 301 according to the present invention is applied to a horizontally-striped fuel cell has been described, but it can also be applied to a so-called vertically-striped fuel cell. Vertically-striped fuel cells are arranged on an insulating support substrate, a power generation unit (fuel electrode, solid electrolyte layer, and air electrode) disposed on one main surface of the support substrate, and on the other main surface of the support substrate. Interconnector.

Modification 2
In the said embodiment, although the 1st junction part a1 of the current collection member 301 was supposed to have the some 1st through-hole c1, you may have only the 1st 1st through-hole c1, or the 1st The through hole c1 may not be provided. Similarly, the second joint portion a2 of the current collecting member 301 has a plurality of second through holes c2, but may have only one second through hole c2, or the second through hole. It may not have c2.

Modification 3
In the above embodiment, the first through hole c1 formed in the first joint portion a1 of the current collecting member 301 extends in the width direction, but may extend in the longitudinal direction as shown in FIG. In this case, the number and size of the first through holes c1 can be appropriately changed. Similarly, the second through hole c2 formed in the second joint portion a2 of the current collecting member 301 extends in the width direction, but may extend in the longitudinal direction as shown in FIG. In this case, the number and size of the second through holes c2 can be changed as appropriate.

Modification 4
In the said embodiment, although the 1st connection part b1 did not have a through-hole, you may have at least 1 through-hole. As a result, the flexibility of the first connecting portion b1 itself can be improved, so that the occurrence of cracks in the first fuel cell 300a and the second fuel cell 300b can be further suppressed. Similarly, the second connecting part b2 has no through hole, but may have at least one through hole. As a result, the flexibility of the second connecting part b2 itself can be improved, so that the occurrence of cracks in the first fuel cell 300a and the second fuel cell 300b can be further suppressed.

Modification 5
In the said embodiment, although the 1st connection part b1 decided to be connected with the one end part P1 of the 1st junction part a1, and the one end part Q1 of the 2nd junction part a2, the 1st junction part a1 and the 2nd junction The position in the width direction is not particularly limited as long as it is connected to the part a2. Similarly, the second connecting part b2 is connected to the other end part P2 of the first joining part a1 and the other end part Q2 of the second joining part a2, but the first joining part a1 and the second joining part The position in the width direction is not particularly limited as long as it is connected to the part a2.

Modification 6
In the above embodiment, each of the first joint part a1, the second joint part a2, the first connection part b1, and the second connection part b2 is arranged to extend in the width direction. It may be inclined.

Modification 7
In the said embodiment, although the current collection member 301 decided to have two connection parts (1st connection part b1 and 2nd connection part b2), as shown in FIG. 11, three connection parts (1st connection part). Part b1, second connecting part b2, and third connecting part b3). In the example shown in FIG. 11, the third connecting portion b3 is disposed at the center in the width direction, but may be disposed between the first connecting portion b1 and the second connecting portion b2, and the position thereof is not particularly limited. . Further, the current collecting member 301 may have four or more connecting portions. Thus, even when the current collecting member 301 has three or more connecting portions, as described in the above embodiment, the total length of each connecting portion with respect to the length L1 of the first joint portion a1. The ratio L4 / L1 of L4 is preferably 0.05 or more and 0.4 or less.

Modification 8
Although not particularly mentioned in the above embodiment, the first joint portion a1 of the current collecting member 301 can be configured as shown in FIG. FIG. 12 is a cross-sectional view of FIG.

  As shown in FIG. 12, the first joint a <b> 1 of the current collecting member 301 is joined to the outer surface Ta of the first fuel cell 300 a through the joining material 102. The first joint portion a1 includes a base material 301X and a chromium oxide film 301Y.

  The substrate 301X is formed in a plate shape. The thickness of the base material 301X is not particularly limited, but can be, for example, 0.1 to 4.0 mm.

  The substrate 301X is made of an alloy containing Cr (chromium). As such an alloy, Fe—Cr alloy steel (stainless steel, etc.), Ni—Cr alloy steel, or the like can be used. Although the content rate of Cr in the base material 301X is not particularly limited, it can be, for example, 4 to 30% by mass.

The base material 301X may contain Ti (titanium) or Al (aluminum). The content ratio of Ti in the base material 301X is not particularly limited, but is 0.01 to 1.0 at. %. Although the content rate of Al in the base material 301X is not particularly limited, for example, 0.01 to 0.4 at. %. The base material 301X may contain Ti as TiO ₂ (titania), or may contain Al as Al ₂ O ₃ (alumina).

  The chromium oxide film 301Y is formed on the base material 301X. The chromium oxide film 301Y covers the base material 301X. The chromium oxide film 301Y preferably covers the entire surface of the base material 301X, but may not partially cover the surface of the base material 301X. The thickness of the chromium oxide film 301Y is not particularly limited, but can be, for example, 1 μm to 20 μm.

The chromium oxide film 301Y contains chromium oxide (Cr ₂ O ₃ ) as a main component. Specifically, the chromium oxide film 301Y contains 50 wt% or more of chromium oxide. The chromium oxide film 301Y may contain Mn, Fe, Cr, Mo, Si, or the like as impurities. The chromium oxide film 301Y can be formed by depositing an oxide film by reacting with a reactive gas (for example, oxygen) by sputtering the Cr target using an RF (radio-frequency) magnetron sputtering apparatus.

  As shown in FIG. 12, the current collecting member 301 includes a first surface Y1, a second surface Y2, and a corner portion Y3 in a cross section perpendicular to the outer surface Ta of the first fuel cell 300a.

  The first surface Y1 has an angle with respect to the outer surface Ta of the first fuel cell 300a. That is, the first surface Y1 is not parallel to the outer surface Ta but is inclined with respect to the outer surface Ta. The first surface Y1 approaches the outer surface Ta as it goes toward the corner Y3. The angle θ1 of the first surface Y1 with respect to the outer surface Ta is not particularly limited, but can be, for example, 0.5 degrees to 45 degrees. In the example shown in FIG. 12, the first surface Y1 is formed flat. However, actually, minute unevenness may be formed.

  In the first surface Y1, the chromium oxide film 301Y preferably covers the base member 301X. The thickness of the chromium oxide film 301 </ b> Y formed on the first surface Y <b> 1 may be formed thicker as it approaches the corner Y <b> 3.

  The second surface Y2 is continuous with the first surface Y1. The second surface Y2 has an angle with respect to the outer surface Ta of the first fuel cell 300a. That is, the second surface Y2 is not parallel to the outer surface Ta but is inclined with respect to the outer surface Ta. The second surface Y2 approaches the outer surface Ta as it goes toward the corner Y3. The angle θ2 of the second surface Y2 with respect to the outer surface Ta is not particularly limited, but can be, for example, 45 degrees to 135 degrees.

  The second surface Y2 has an angle with respect to the first surface Y1. That is, the second surface Y2 is not parallel to the first surface Y1, but is inclined with respect to the first surface Y1. The angle θ3 of the second surface Y2 with respect to the first surface Y1 is not particularly limited, but can be, for example, 30 degrees to 135 degrees. In the example shown in FIG. 12, the second surface Y2 is formed flat, but in actuality, minute irregularities may be formed.

  In the second surface Y2, the chromium oxide film 301Y preferably covers the base material 301X. The thickness of the chromium oxide film 301Y formed on the second surface Y2 may be formed thicker as it approaches the corner Y3.

  The corner Y3 is formed by the first surface Y1 and the second surface Y2. In the present embodiment, “formed by the first surface Y1 and the second surface Y2” means “defined by the first surface Y1 and the second surface Y2”, “the first surface Y1 and the second surface. It means at least one of “partitioned by Y2” and “provided between the first surface Y1 and the second surface Y2.”

  The corner portion Y3 may be formed such that the first surface Y1 and the second surface Y2 are bent so that the first surface Y1 and the second surface Y2 are one or more other surfaces (curved). (A surface or a bent surface).

  In the corner portion Y3, the chromium oxide film 301Y preferably covers the base member 301X. The chromium oxide film 301Y formed at the corner portion Y3 may be formed thicker than the other portions around the corner portion Y3.

  The corner Y3 is closer to the outer surface Ta of the first fuel cell 300a than each of the first surface Y1 and the second surface Y2. In the present modification, the corner Y3 is a part of the current collecting member 301 that is closest to the outer surface Ta of the first fuel cell 300a. The distance D from the corner Y3 to the outer surface Ta is not particularly limited, but can be 0.5 to 2000 μm.

  The current flowing from the first fuel cell 300a to the current collecting member 301 or the current flowing from the current collecting member 301 to the first fuel cell 300a is applied to the outer surface Ta of the first fuel cell 300a in the current collecting member 301. Concentrate on the adjacent corner Y3. When current concentrates on the corner Y3, the temperature of the chromium oxide film 301Y formed on the corner Y3 increases, and the electrical resistance of the chromium oxide film 301Y decreases. As a result, since the current can flow smoothly from the first fuel cell 300a to the current collecting member 301 or from the current collecting member 301 to the first fuel cell 300a, the first fuel cell 300a and the current collecting member The electrical connectivity with 301 can be improved.

  Further, since each of the first surface Y1 and the second surface Y2 forming the corner portion Y3 has an angle with respect to the outer surface Ta, the joining material 102 is inserted when the corner portion Y3 is inserted into the joining material 102. The bubbles inside can be excluded from the periphery of the corner Y3. As a result, the electrical connectivity between the first fuel cell 300a and the current collecting member 301 can be further improved.

  The modification of the configuration of the first joint portion a1 of the current collecting member 301 has been described above. However, such a configuration can also be applied to the second joint portion a2 of the current collection member 301.

  An example is shown below and the suitable size of the through-hole formed in the junction part of a current collection member is demonstrated concretely. In addition, this invention is not limited to the following Example.

  A plurality of current collecting members 301 configured as shown in FIGS. 7 to 9 were produced. However, the ratio A2 / A1 of the area A2 of the inner wall surface Sc1 that defines the through hole c1 with respect to the area A1 of the first joint a1 was changed for each current collecting member 301. Table 1 shows the area A1 of the first joint portion a1 of each current collecting member 301, the total value A2 of the areas of the inner wall surface Sc1 of the plurality of through holes c1, and the ratio A2 / A1.

  Each current collecting member 301 produced as described above was joined to the air electrode current collector 62 of the first fuel cell 300a via the joining material 102. Then, the bonding material 102 was solidified by heat treatment. The heat treatment temperature at this time was 900 ° C., and the heat treatment time was 1 hr.

  As shown in FIG. 8, the bonding material 102 is filled between the first main surface Sa1 of the first bonding portion a1 and the outer surface Ta of the first fuel cell 300a and in each through hole c1. Note that the bonding material 102 does not protrude from the outer surface of the first bonding portion a1. The materials of the bonding material 102, the current collector 301 and the air electrode current collector 62 are as shown in Table 1, and the materials of the end current collector 3 are SUS445J1 (Cr content 22 wt.%), SUS430 (Cr content). 16 wt.%) Was used. Other conditions were basically the same for each sample.

(Evaluation method)
A thermal cycle test was performed on each of the samples 1 to 26 produced as described above. Specifically, first, the temperature was raised from room temperature to 800 ° C. at a rate of temperature rise of 300 ° C./hr, maintained at 800 ° C. for 2 hr, and then the cycle of lowering the temperature to 300 ° C./hr to 50 ° C. was repeated 20 times.

  Then, the presence or absence of peeling in each sample was confirmed. Specifically, it was confirmed by observing with an optical microscope whether peeling occurred between the first bonding part a1 and the bonding material 102 or not.

  The above results are shown in Table 1 as evaluation. The evaluation “◯” in Table 1 means that no peeling occurred in the thermal cycle test. The evaluation “Δ” in Table 1 means that peeling occurred in the thermal cycle test.

  As shown in Table 1, the ratio A2 / A1 of the area A2 of the inner wall surface Sc1 that defines the through hole c1 to the area A1 of the first joint a1 viewed from the first main surface Sa1 side is 0.1 or more. Thus, it was found that peeling between the first joint portion a1 and the joining material 102 can be suppressed.

100 cell stack 102 bonding material 200 fuel manifold 300 fuel cell 300a first fuel cell 300b second fuel cell 301 current collecting member a1 first joint a2 second joint b1 first connection b2 second connection c1 1st through-hole c2 2nd through-hole

Claims (10)

A first fuel cell extending in the longitudinal direction;
A second fuel cell adjacent to the first fuel cell and extending in the longitudinal direction;
A current collecting member disposed between the first fuel cell and the second fuel cell and electrically connecting the first fuel cell and the second fuel cell;
With
The current collecting member is
A flat plate-like first joint joined to the first fuel cell;
A flat plate-like second joint joined to the second fuel cell and facing the first joint;
A curved plate-like first coupling portion coupled to the first joint portion and the second joint portion;
A curved plate-like second connecting portion connected to the first connecting portion and the second connecting portion;
Have
Each of the first connecting portion and the second connecting portion is disposed outside the gap between the first joint portion and the second joint portion in the longitudinal direction.
Cell stack. Each of the first joint and the second joint extends in a width direction perpendicular to the longitudinal direction.
The cell stack according to claim 1. The first connecting portion is connected to one end portion of the first joint portion in the width direction and one end portion of the second joint portion in the width direction,
The second connecting portion is connected to the other end portion of the first joint portion in the width direction and the other end portion of the second joint portion in the width direction.
The cell stack according to claim 2. The first joint is joined to the first fuel cell via a joining material,
The first joint has a through hole filled with the joining material.
The cell stack according to claim 1. The first joint portion has a main surface joined to the first fuel cell via the joining material,
The ratio of the area of the inner wall surface that defines the through hole to the area of the first joint portion viewed from the main surface side is 0.1 or more.
The cell stack according to claim 4. The first joint is joined to the first fuel cell via a joining material,
The first joint has a base material made of an alloy containing Cr, and a chromium oxide film covering the base material,
In a cross section perpendicular to the outer surface of the first fuel cell, the first joint portion includes a first surface having an angle with respect to the outer surface, and a second surface having an angle with respect to the outer surface; Including a corner formed by the first surface and the second surface;
The corner is closer to the outer surface than each of the first surface and the second surface;
The cell stack according to claim 1. The second joint is joined to the second fuel cell via a joining material,
The second joint has a through hole filled with the joining material.
The cell stack according to claim 1. The current collecting member has a curved plate-like third connecting portion connected to the first connecting portion and the second connecting portion.
The cell stack according to claim 1. When the first joint is viewed in plan, the ratio of the total length of the first joint and the second joint with respect to the length of the first joint in the width direction perpendicular to the longitudinal direction is: 0.4 or less,
The cell stack according to claim 1. When the first joint is viewed in plan, the ratio of the total length of the first joint and the second joint with respect to the length of the first joint in the width direction perpendicular to the longitudinal direction is: 0.05 or more,
The cell stack according to claim 1.

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