JP6378742B2 - Fuel cell stack - Google Patents

Description

  The present invention relates to a fuel cell stack.

  The fuel cell stack includes a manifold and at least one fuel cell. At least one fuel battery cell has a gas flow path. The manifold is configured to distribute gas to the fuel cells. Specifically, the manifold has a bottom wall, a side wall, and a top wall. The bottom wall, the side wall, and the top wall define an internal space of the manifold. The side wall of the manifold has a gas inlet. Gas is introduced into the internal space of the manifold through this gas inlet. This gas is introduced along the depth direction of the internal space of the manifold. The fuel battery cell is attached to the upper wall of the manifold.

Japanese Patent Laying-Open No. 2015-76339

  It is preferable that the stress generated in each fuel cell due to the deformation or displacement of the gas inlet is small. In particular, cracks presumed to be caused by stress derived from the displacement of the gas inlet, etc., originated from the gas flow path closest to the gas inlet. Therefore, an object of the present invention is to reduce the stress generated in the gas flow path closest to the gas inlet.

The fuel cell stack according to the first aspect of the present invention includes a manifold and at least one fuel cell. The fuel battery cell is attached to the manifold. At least one fuel battery cell has a plurality of gas flow paths as a whole. For example, when the fuel cell stack includes only one fuel cell, the one fuel cell has a plurality of gas flow paths. Further, when the fuel cell stack includes a plurality of fuel cells, each fuel cell may have one gas flow path, or each fuel cell may have a plurality of gas flow paths. Good. The manifold has a bottom wall, a side wall, and a top wall. The side wall has a gas inlet opening that opens in the first direction. The side wall extends upward from the bottom wall. Each fuel battery cell is attached to the upper wall. A first line formed between a line connecting the center of the lower end surface of the gas flow path closest to the gas introduction port and the center of the gas introduction port and a plane passing through the center of the gas introduction port and parallel to the bottom wall. The angle is 77 ° or less.

According to this configuration, since the first angle is set to 77 ° or less, stress generated in the gas flow path closest to the gas introduction port due to deformation or displacement of the gas introduction port is reduced, and cracks are less likely to occur. .

  Preferably, the first angle is 13 ° or more. According to this configuration, when a plurality of gas flow paths are spaced from each other in the first direction and communicate with the manifold, it is possible to suppress an excessive gas supply amount to the flow path closest to the gas inlet. can do. In addition, the plurality of gas flow paths arranged in the first direction may be configured by each gas flow path of a plurality of fuel cells, or may be configured by each gas flow path of one fuel cell. Also good.

  Preferably, the fuel cell stack includes a plurality of fuel cells. The proximal fuel cell closest to the gas inlet has a plurality of gas flow paths. Each gas flow path is arrange | positioned at intervals in the 2nd direction. The second direction is orthogonal to the first direction and extends in the horizontal direction. Of each gas flow path of the proximal fuel cell, the second angle formed by each line connecting the center of the lower end surface of each gas flow path that is outermost in the second direction and the center of the gas inlet is 85 ° or more. It is. According to this configuration, a difference in gas flow rate between the fuel cells can be suppressed.

  Preferably, the fuel cell stack includes a plurality of fuel cells. At least some of the plurality of gas flow paths are spaced from each other in the second direction. The second direction is orthogonal to the first direction and extends in the horizontal direction. Of the gas flow paths that are spaced apart from each other in the second direction, the second line formed by each line connecting the center of the lower end surface of each gas flow path that is outermost in the second direction and the center of the gas introduction port. The angle is 85 ° or more. According to this configuration, a difference in gas flow rate between the fuel cells can be suppressed. In addition, the plurality of gas flow paths arranged at intervals in the second direction may be configured by each gas flow path of the plurality of fuel cells, or each gas flow path of one fuel cell. You may be comprised from.

The fuel cell stack according to the second aspect of the present invention includes a manifold and fuel cells. The fuel cell has a gas flow path and is attached to the manifold. The manifold has a bottom wall, side walls, and a top wall. The side wall has a gas inlet opening in the first direction and extends upward from the bottom wall. Each fuel battery cell is attached to the upper wall. A first angle formed by a line connecting the center of the lower end surface of the gas flow path and the center of the gas inlet and a plane passing through the center of the gas inlet and parallel to the bottom wall is 77 ° or less.

According to this configuration, since the first angle is set to 77 ° or less, stress generated in the gas flow path closest to the gas introduction port due to deformation or displacement of the gas introduction port is reduced, and cracks are less likely to occur. .

  Preferably, the side wall has a pair of first side walls and a pair of second side walls. The pair of first side walls oppose each other in the first direction. The pair of second side walls oppose each other in the second direction. The inner surface of the first boundary portion between the first side wall and the second side wall has an R shape. According to this configuration, in the case where a plurality of fuel cells are provided, a difference in gas flow rate between the fuel cells can be suppressed.

  Preferably, the inner side surface of the second boundary portion between the bottom wall and the side wall has an R shape. According to this configuration, in the case where a plurality of fuel cells are provided, a difference in gas flow rate between the fuel cells can be suppressed.

  Preferably, the manifold further includes a first flange portion extending outward from the side wall. The upper wall is fixed to the first flange portion.

  Preferably, the inner side surface of the third boundary portion between the side wall and the first flange portion has an R shape. According to this configuration, in the case where a plurality of fuel cells are provided, a difference in gas flow rate between the fuel cells can be suppressed.

  Preferably, a first gap portion is formed between the third boundary portion and the upper wall. Compared to a manifold that does not have the first gap portion, the manifold is easily deformed in the first gap portion. For this reason, for example, when the fuel cell is fixed to the manifold with a bonding material, the stress generated in the bonding material is reduced, so that the reliability of the fuel cell stack is improved.

  Preferably, the inner side surface of the fourth boundary portion between the upper wall and the first and second side walls has an R shape. According to this configuration, in the case where a plurality of fuel cells are provided, a difference in gas flow rate between the fuel cells can be suppressed.

  Preferably, the manifold further includes a second flange portion extending outward from the lower end portions of the first side wall and the second side wall. The bottom wall is fixed to the second flange portion.

  Preferably, the inner surface of the fifth boundary portion between the first side wall and the second side wall and the second flange portion has an R shape. According to this configuration, in the case where a plurality of fuel cells are provided, a difference in gas flow rate between the fuel cells can be suppressed.

  Preferably, a second gap portion is formed between the fifth boundary portion and the bottom wall. Compared to a manifold that does not have the second gap portion, the manifold is easily deformed in the second gap portion. For this reason, for example, when the fuel cell is fixed to the manifold with a bonding material, the stress generated in the bonding material is reduced, so that the reliability of the fuel cell stack is improved.

  ADVANTAGE OF THE INVENTION According to this invention, the stress which arises in the gas flow path arrange | positioned nearest to the gas inlet can be reduced.

The perspective view of a fuel cell stack. Sectional drawing of a fuel cell stack. III-III sectional view taken on the line of FIG. FIG. 4 is a sectional view taken along line IV-IV in FIG. 2. The expanded sectional view of a manifold. The expanded sectional view of a manifold. The VII-VII sectional view taken on the line of FIG. The expanded sectional view of a manifold. The top view of an upper wall. The perspective view of a fuel cell. The expanded sectional view of a fuel cell stack. The expanded sectional view of a fuel cell stack. Sectional drawing of a fuel cell. The expanded sectional view of a fuel cell stack. Sectional drawing which shows the manufacturing method of a fuel cell stack. Sectional drawing which shows the manufacturing method of a fuel cell stack. Sectional drawing of the manifold which concerns on a modification. The expanded sectional view of the manifold which concerns on a modification.

[Fuel cell stack]
Hereinafter, an embodiment of a fuel cell stack according to the present invention will be described with reference to the drawings. As shown in FIGS. 1 to 3, the fuel cell stack 100 includes a plurality of fuel cells 1 and a manifold 2.

[Manifold]
The manifold 2 is configured to distribute gas to each fuel cell 1. The manifold 2 is hollow and has an internal space. A gas such as fuel gas is introduced into the internal space of the manifold 2 through the introduction pipe 201. The manifold 2 has a plurality of through holes 27 that allow the internal space to communicate with the outside.

  The manifold 2 supports each fuel cell 1. The manifold 2 includes a manifold body 21 and an upper wall 22. The manifold body 21 and the upper wall 22 are separate members and are joined to each other. The manifold body 21 and the upper wall 22 may be integrally formed. The manifold body 21 and the upper wall 22 define an internal space of the manifold 2. The internal space is preferably a rectangular parallelepiped, but the shape of the internal space is not particularly limited.

  The manifold body 21 has a rectangular parallelepiped shape and has an internal space whose upper surface is open. Specifically, the manifold main body 21 has a bottom wall 23, a pair of first side walls 24, and a pair of second side walls 25. Further, the manifold body 21 may have a first flange portion 26.

  The bottom wall 23 has a rectangular shape in plan view (viewed in the x-axis direction). Each first side wall 24 and each second side wall 25 extend upward from the peripheral edge of the bottom wall 23. The pair of first side walls 24 are arranged to face each other in the depth direction (z-axis direction) of the internal space of the manifold 2. The pair of second side walls 25 are disposed so as to face each other in the width direction (y-axis direction) of the internal space of the manifold 2. The depth direction (z-axis direction) corresponds to the first direction of the present invention. The width direction (y-axis direction) corresponds to the second direction of the present invention.

  As shown in FIG. 4, one first side wall 24 of the pair of first side walls 24 has an opening 241. The introduction pipe 201 is attached to the first side wall 24 in which the opening 241 is formed. For example, as shown in FIG. 5, the introduction pipe 201 may be in contact with the outer surface of the first side wall 24. In this case, the opening 241 of the first side wall 24 corresponds to the gas inlet of the present invention. As shown in FIG. 6, the introduction tube 201 may be inserted into the opening 241. In this case, the opening of the introduction pipe 201 corresponds to the gas introduction port of the present invention. The introduction pipe 201 may not be attached in parallel to the bottom wall 23. The gas inlet is preferably formed in the center of the first side wall 24 in the width direction (y-axis direction). Gas is introduced into the internal space of the manifold 2 from this gas inlet. The gas inlet is opened in the depth direction (z-axis direction). The gas inlet is formed in a circular shape. In the following description, it is assumed that the opening 241 of the first side wall 24 corresponds to a gas inlet as shown in FIG.

  The flow rate of the gas introduced into the internal space of the manifold 2 is preferably about 0.60 to 45 m / s at the inlet. This flow rate is a flow rate in terms of 0 ° C. · 1 atm during fuel cell power generation. The flow rate can be calculated from the flow rate introduced into the manifold 2 and the cross-sectional area of the introduction port 241.

  The first flange portion 26 extends outward from the upper end portions of the first side walls 24 and the second side walls 25. The first flange portion 26 is annular.

The manifold body 21 is composed of one member. That is, the bottom wall 23, each first side wall 24, each second side wall 25, and each first flange portion 26 are configured by one member. For example, the manifold body 21 is formed of a metal having heat resistance or insulating ceramics. More specifically, the manifold body 21 is made of ferritic stainless steel, austenitic stainless steel, and Ni-based alloy, MgO (magnesium oxide), Al ₂ O ₃ (aluminum oxide), MgAl ₂ O ₄ (magnesia alumina spinel). , MgO · SiO ₂ (steatite), and 2MgO · SiO ₂ (forsterite).

  As shown in FIG. 7, the inner side surface of the first boundary portion 20 a between the first side wall 24 and the second side wall 25 has an R shape. The curvature radius of the inner surface of the first boundary portion 20a can be about 3 to 30 mm. Note that the inner side surface of the first boundary portion 20 a is a surface facing the inner space of the manifold 2.

  As shown in FIG.4 and FIG.8, the inner surface of the 2nd boundary part 20b of the bottom wall 23 and the 1st side wall 24 and the 2nd side wall 25 is R shape. The radius of curvature of the inner surface of the second boundary portion 20b can be about 2 to 20 mm. Note that the inner side surface of the second boundary portion 20 b is a surface facing the inner space of the manifold 2.

  The inner side surface of the third boundary portion 20c between the first side wall 24 and the second side wall 25 and the first flange portion 26 has an R shape. The curvature radius of the inner surface of the third boundary portion 20c can be about 1 to 10 mm. The inner side surface of the third boundary portion 20 c is a surface that faces the internal space of the manifold 2.

  As shown in FIG. 8, a first gap portion 28 is formed between the third boundary portion 20 c and the upper wall 22 in the height direction (x-axis direction) of the internal space of the manifold 2. That is, the lower surface of the upper wall 22 and the upper surface of the first flange portion 26 are in contact with each other, while the lower surface of the upper wall 22 and the inner surface of the third boundary portion 20c are not in contact with each other. The first gap 28 is formed over the entire circumference.

  As shown in FIG. 4, the upper wall 22 is disposed on the manifold body 21 so as to close the upper surface of the manifold body 21. Specifically, the upper wall 22 is fixed to the first flange portion 26. In order to seal the internal space of the manifold 2, the upper wall 22 is joined to the manifold body 21 over the entire circumference. For example, the upper wall 22 and the manifold body 21 are joined by crystallized glass. The upper wall 22 can be formed from at least one of the materials of the manifold body 21 described above.

  As shown in FIG. 9, the upper wall 22 is configured such that each fuel cell 1 is attached. Specifically, the upper wall 22 has a plurality of through holes 27. Each through hole 27 extends in the width direction (y-axis direction) of the manifold 2. Further, the through holes 27 are arranged at intervals in the depth direction (z-axis direction) of the manifold 2.

  As shown in FIGS. 7 and 8, the internal space of the manifold 2 has a depth D, a width W, and a height H1 that are orthogonal to each other. The depth D is a dimension of the internal space in the gas introduction direction (z-axis direction). That is, the depth D is a distance between the pair of first side walls 24.

  The width W is a dimension of the internal space in a direction orthogonal to the depth D in plan view (view in the x-axis direction). That is, the width W is a distance between the pair of second side walls 25. The height H1 is a dimension of the internal space in a direction orthogonal to the depth D and the width W. That is, the height H1 is the distance between the upper wall 22 and the bottom wall 23.

  The depth D of the internal space can be about 50 to 450 mm. The width W of the internal space can be about 30 to 200 mm. The height H of the internal space can be about 5 to 50 mm.

[Fuel battery cell]
As shown in FIGS. 1 to 3, each fuel cell 1 is attached to a manifold 2. Each fuel cell 1 extends upward from the manifold 2. Specifically, each fuel cell 1 extends upward from the upper wall 22 of the manifold 2. The lower end portion 101 of the fuel cell 1 is inserted into the through hole 27. At this time, the lower end portion of the fuel battery cell may protrude downward from the upper wall 22 by about 5 mm. The length of the fuel cell 1 in the longitudinal direction (x-axis direction) can be about 100 to 300 mm. In the state where the lower end portion 101 of the fuel cell 1 is inserted into the through hole 27, a gap is formed between the outer peripheral surface of the lower end portion 101 of the fuel cell 1 and the inner wall surface of the through hole 27. Yes. The gap may be filled with the first bonding material 3.

  The fuel cells 1 are arranged at intervals in the depth direction (z-axis direction) of the manifold 2. In addition, each fuel cell 1 does not need to be arrange | positioned at equal intervals along a longitudinal direction. In FIG. 1, the fuel cells 1 are arranged in one row, but the fuel cells 1 may be arranged in a plurality of rows. In addition, the fuel cell 1 arrange | positioned nearest to the gas inlet 241 among each fuel cell 1 is called the proximal fuel cell 1a. Each fuel cell 1 is arranged such that each main surface faces the depth direction (z-axis direction). The fuel cells 1 are electrically connected to each other via the first current collecting member 4. The first current collecting member 4 is disposed between the fuel cells 1 and connects the adjacent fuel cells 1. The first current collecting member 4 is joined to each fuel cell 1 by a second joining material 5. The first current collecting member 4 is formed from a conductive material. For example, the first current collecting member 4 is formed of a sintered body of oxide ceramics or a metal.

  As shown in FIG. 10, the fuel cell 1 includes a plurality of power generation element portions 11 and a support substrate 12. Each power generating element portion 11 is supported on both surfaces of the support substrate 12. Each power generation element unit 11 may be supported only on one side of the support substrate 12. The respective power generation element portions 11 are arranged at intervals in the longitudinal direction of the fuel battery cell 1. That is, the fuel cell 1 according to the present embodiment is a so-called horizontal stripe type fuel cell.

  The power generating element portions 11 are electrically connected to each other by an electrical connection portion 17 (see FIG. 13). Further, on the upper end portion 102 side of the fuel cell 1, the power generation element portion 11 formed on one surface of the support substrate 12 and the power generation element portion 11 formed on the other surface are the second current collecting member 6 (see FIG. 2). ) Is electrically connected. Each power generating element unit 11 is connected in series.

As shown in FIG. 3, the support substrate 12 has a plurality of gas flow passages 121 extending in the longitudinal direction (x-axis direction) of the support substrate 12 inside. The gas flow path 121 communicates with the internal space of the manifold 2. The gas flow paths 121 are arranged at intervals from each other in the width direction (y-axis direction) of the support substrate 12. That is, the gas flow paths 121 are arranged at intervals from each other in the width direction (y-axis direction) of the manifold 2. The area of each gas channel 121 can be about 0.1 to 30 mm ² .

  Among the gas flow paths 121 of the fuel battery cell 1, the gas flow paths 121 formed at both ends are disposed so as to correspond to the widthwise ends of the internal space of the manifold 2. For example, the distance L1 between the center of the lower end surface of the gas flow path 121 formed at both ends in the width direction and the inner wall surface of the second side wall 25 is about 0.5 to 15 mm. In addition, let the distance between the centers of the lower end surfaces of the gas flow path 121 formed in the both ends of the width direction be distance L2.

  As shown in FIG. 11, the gas flow path 121 closest to the gas inlet 241 among the gas flow paths 121 is referred to as a proximal gas flow path 121a. The proximal gas channel 121a is formed in the proximal fuel cell 1a. Of the plurality of gas flow paths 121 included in the proximal fuel cell 1a, the gas flow path 121 closest to the gas inlet 241 in the second direction is the proximal gas flow path 121a. A distance in the depth direction (z-axis direction) between the center of the lower end surface of the proximal gas flow path 121a and the gas introduction port 241 is a distance L3. The distance in the height direction (x-axis direction) between the lower end surface of the proximal gas flow path 121a and the center of the gas inlet 241 is defined as a distance L4.

A first angle θ1 formed by a line connecting the center of the lower end surface of the proximal gas flow path 121a and the center of the gas introduction port 241 and a plane passing through the center of the gas introduction port 241 and parallel to the bottom wall 23 is 77 ° or less. The first angle θ1 is preferably 13 ° or more. The center of the gas inlet 241 means the center of the boundary surface between the front end surface of the gas inlet 241, that is, the internal space of the manifold 2.

  As shown in FIG. 12, the proximal fuel cell 1a has a plurality of gas flow paths 121 arranged at intervals in the width direction (y-axis direction). The center of the lower end surface of the two gas flow paths 121 arranged on the outermost side in the width direction (y-axis direction) and the center of the gas introduction port 241 among the gas flow paths 121 of the proximal fuel cell 1a. The second angle θ2 formed by the connected lines is preferably 85 ° or more.

  The longitudinal direction (x-axis direction) of the support substrate 12 is the same direction as the longitudinal direction of the fuel cell 1. Each gas channel 121 extends substantially parallel to each other. Each gas flow path 121 is open at both end faces in the longitudinal direction of the support substrate 12.

  As shown in FIG. 13, the support substrate 12 has a plurality of first recesses 123. Each first recess 123 is formed on both surfaces of the support substrate 12. The first recesses 123 are arranged at intervals in the longitudinal direction of the support substrate 12.

The support substrate 12 is made of a porous material that does not have electronic conductivity. The support substrate 12 can be made of, for example, CSZ (calcia stabilized zirconia). Alternatively, the support substrate 12 may be composed of NiO (nickel oxide) and YSZ (8YSZ) (yttria stabilized zirconia), or composed of NiO (nickel oxide) and Y ₂ O ₃ (yttria). Alternatively, MgO (magnesium oxide) and MgAl ₂ O ₄ (magnesia alumina spinel) may be used. The porosity of the support substrate 12 is, for example, about 20 to 60%.

  Each power generation element unit 11 includes a fuel electrode 13, an electrolyte 14, and an air electrode 15. Each power generation element unit 11 further includes a reaction preventing film 16. The fuel electrode 13 is a fired body made of a porous material having electron conductivity. The fuel electrode 13 includes a fuel electrode current collector 131 and a fuel electrode active part 132.

  The fuel electrode current collector 131 is disposed in the first recess 123. Specifically, the fuel electrode current collector 131 is filled in the first recess 123 and has the same outer shape as the first recess 123. Each fuel electrode current collector 131 has a second recess 131a and a third recess 131b. The anode active part 132 is disposed in the second recess 131a. Specifically, the fuel electrode active part 132 is filled in the second recess 131a.

The fuel electrode current collector 131 can be composed of, for example, NiO (nickel oxide) and YSZ (8YSZ) (yttria stabilized zirconia). Alternatively, the fuel electrode current collector 131 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 131 and the depth of the first recess 123 are about 50 to 500 μm.

  The fuel electrode active part 132 can be composed of, for example, NiO (nickel oxide) and YSZ (8YSZ) (yttria stabilized zirconia). Alternatively, the fuel electrode active part 132 may be composed of NiO (nickel oxide) and GDC (gadolinium-doped ceria). The thickness of the fuel electrode active part 132 is 5 to 30 μm.

  The electrolyte 14 is disposed so as to cover the fuel electrode 13. Specifically, the electrolyte 14 extends in the longitudinal direction from one interconnector 171 to another interconnector 171. That is, the electrolyte 14 and the interconnector 171 are alternately arranged in the longitudinal direction of the fuel cell 1.

  The electrolyte 14 is a fired body made of a dense material that has ionic conductivity and no electronic conductivity. The electrolyte 14 can be composed of, for example, YSZ (8YSZ) (yttria stabilized zirconia). Or the electrolyte 14 may be comprised from LSGM (lanthanum gallate). The thickness of the electrolyte 14 is, for example, about 3 to 50 μm.

  The reaction preventing film 16 is a fired body composed of a dense material. The reaction preventing film 16 is disposed between the electrolyte 14 and the air electrode 15. The reaction preventing film 16 suppresses occurrence of a phenomenon in which a reaction layer having a large electric resistance is formed at the interface between the electrolyte 14 and the air electrode 15 due to a reaction between YSZ in the electrolyte 14 and Sr in the air electrode 15. Is provided.

The reaction preventing film 16 is made of a material containing ceria containing a rare earth element. The reaction preventing film 16 can be made of, for example, GDC = (Ce, Gd) O ₂ (gadolinium-doped ceria). The thickness of the reaction preventing film 16 is, for example, about 3 to 50 μm.

The air electrode 15 is disposed on the reaction preventing film 16. The air electrode 15 is a fired body made of a porous material having electron conductivity. The air electrode 15 can be made of, for example, LSCF = (La, Sr) (Co, Fe) O ₃ (lanthanum strontium cobalt ferrite). Alternatively, the air electrode 15 has 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 15 may be composed of two layers of a first layer (inner layer) made of LSCF and a second layer (outer layer) made of LSC. The thickness of the air electrode 15 is, for example, 10 to 100 μm.

The electrical connection portion 17 is configured to electrically connect adjacent power generation element portions 11. The electrical connection unit 17 includes an interconnector 171 and an air electrode current collector 172. The interconnector 171 is disposed in the third recess 131b. Specifically, the interconnector 171 is embedded (filled) in the third recess 131b. The interconnector 171 is a fired body composed of a dense material having electronic conductivity. The interconnector 171 can be composed of, for example, LaCrO ₃ (lanthanum chromite). Alternatively, the interconnector 171 may be made of (Sr, La) TiO ₃ (strontium titanate). The thickness of the interconnector 171 is, for example, 10 to 100 μm.

  Air electrode current collector 172 is arranged to extend between interconnector 171 and air electrode 15. For example, the air electrode current collector 172 is disposed so as to electrically connect the air electrode 15 of the power generation element unit 11 disposed on the left side of FIG. 13 and the interconnector 171. The air electrode current collector 172 is a fired body made of a porous material having electronic conductivity.

The air electrode current collector 172 can be made of, for example, LSCF = (La, Sr) (Co, Fe) O ₃ (lanthanum strontium cobalt ferrite). Alternatively, the air electrode current collector 172 may be made of LSC = (La, Sr) CoO ₃ (lanthanum strontium cobaltite). Or the air electrode current collection part 172 may be comprised from Ag (silver) and Ag-Pd (silver palladium alloy). The thickness of the air electrode current collector 172 is, for example, about 50 to 500 μm.

  As shown in FIG. 14, the lower end portion 101 of the fuel cell 1 is covered with a dense film 18. Specifically, the dense film 18 covers the support substrate 12. The dense film 18 extends downward from between the air electrode current collector 172 and the support substrate 12.

  The dense membrane 18 exhibits a gas seal function that prevents mixing of the fuel gas flowing in the space inside the dense membrane 18 and the air flowing in the space outside the dense membrane 18. In order to exhibit this gas sealing function, the porosity of the dense film 18 is, for example, 10% or less. The dense film 18 is made of insulating ceramics.

  Specifically, the dense film 18 can be constituted by the electrolyte 14 and the reaction preventing film 16 described above. The electrolyte 14 constituting the dense film 18 covers the support substrate 12 and extends from the interconnector 171 to the vicinity of the lower end of the support substrate 12. Further, the reaction preventing film 16 constituting the dense film 18 is disposed between the electrolyte 14 and the air electrode current collector 172. The dense film 18 may be composed of only the electrolyte 14 or may be composed of a material other than the electrolyte 14 and the reaction preventing film 16.

[First bonding material]
The first bonding material 3 fixes the fuel cell 1 to the manifold 2. Specifically, the first bonding material 3 joins the fuel battery cell 1 and the upper wall 22 of the manifold 2. The first bonding material 3 joins the lower end portion 101 of the fuel cell 1 and the upper wall 22 of the manifold 2. The first bonding material 3 is in contact with the dense film 18. In the state where the fuel battery cell 1 is fixed to the manifold 2, the through hole 27 and the gas flow path 121 communicate with each other.

The first bonding material 3 is, for example, crystallized glass. As the crystallized glass, for example, a SiO ₂ —B ₂ O ₃ system, a SiO ₂ —CaO system, or a SiO ₂ —MgO system may be employed. In this specification, crystallized glass means that the ratio (crystallinity) of “volume occupied by crystal phase” to the total volume is 60% or more, and “volume occupied by amorphous phase and impurities relative to the total volume”. "Indicates a glass having a ratio of less than 40%. Note that amorphous glass, brazing material, ceramics, or the like may be employed as the material of the first bonding material 3. Specifically, the first bonding material 3 is at least one selected from the group consisting of SiO ₂ —MgO—B ₂ O ₅ —Al ₂ O ₃ and SiO ₂ —MgO—Al ₂ O ₃ —ZnO. .

[Power generation method]
The fuel cell stack 100 configured as described above generates power as follows. By flowing a fuel gas (hydrogen gas or the like) through the manifold 2 into the gas flow path 121 of each fuel battery cell 1 and exposing both surfaces of the support substrate 12 to a gas (air or the like) containing oxygen, An electromotive force is generated by a difference in oxygen partial pressure generated between the two side surfaces. When this fuel cell stack 100 is connected to an external load, an electrochemical reaction shown in the following formula (1) occurs in the air electrode 15, an electrochemical reaction shown in the following formula (2) occurs in the fuel electrode 13, and a current flows. .
(1/2) · O ₂ + 2e ⁻ → O ₂ ⁻ (1)
H ₂ + O ₂ ⁻ → H ₂ O + 2e ⁻ (2)

[Production method]
Next, a method for manufacturing the fuel cell stack configured as described above will be described.

  First, a manifold 2 and a plurality of fuel cells 1 are prepared. Then, as shown in FIG. 15, the fuel cells 1 are connected to each other by the first current collecting member 4 and the second bonding material 5 to produce the cell assembly 300. At this stage, the second bonding material 5 is not fired, and the fuel cells 1 are temporarily fixed to each other.

  Next, as shown in FIG. 16, the lower end portion 101 of each fuel cell 1 of the cell assembly 300 is inserted into each through hole 27 of the manifold 2. In addition, you may use the jig | tool for each fuel battery cell 1 holding a predetermined space | interval along the thickness direction.

  Next, as shown in FIG. 2, the first bonding material 3 is applied so as to bond the fuel cell 1 inserted into the through hole 27 and the upper wall 22 of the manifold. The first bonding material 3 is applied along the root of the fuel cell 1. Further, the first bonding material 3 may be filled in a gap between the outer peripheral surface of the lower end portion 101 of the fuel cell 1 and the inner wall surface of the through hole 27.

  Next, heat treatment is applied to the first bonding material 3 and the second bonding material 5. By this heat treatment, the first bonding material 3 and the second bonding material 5 are solidified, and the fuel cell stack 100 is completed. Specifically, the second bonding material 5 is fired by being subjected to heat treatment. As a result, each fuel cell 1 and the first current collecting member 4 are fixed. Further, the first bonding material 3 is subjected to heat treatment, so that the temperature of the amorphous material reaches the crystallization temperature. Then, a crystal phase is generated inside the material at the crystallization temperature, and crystallization proceeds. As a result, the amorphous material is solidified and ceramicized to become crystallized glass. Thereby, the 1st joining material 3 comprised with crystallized glass exhibits a function, and the lower end part 101 of each fuel cell 1 is fixed to the upper wall 22 of the manifold 2. As shown in FIG.

[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 fuel electrode current collector 131 has the second recess 131a and the third recess 131b, but the configuration of the fuel electrode current collector 131 is not limited to this. For example, the fuel electrode current collector 131 does not have to have recesses such as the second recess 131a and the third recess 131b. In this case, the anode active portion 132 is formed on the anode current collecting portion 131 and is not embedded in the anode current collecting portion 131. The interconnector 171 is formed on the fuel electrode current collector 131 and is not embedded in the fuel electrode current collector 131.

Modification 2
In the above embodiment, the fuel battery cell 1 is a horizontal stripe type having a plurality of power generation element portions 11. However, the fuel battery cell 1 is a vertical stripe type having a single power generation element portion extending in the longitudinal direction. It may be. Further, the fuel cell 1 may be a horizontal stripe cylindrical type.

Modification 3
In the above embodiment, the gas inlet 241 has a circular shape, but the shape of the gas inlet is not particularly limited to this, and may be, for example, an ellipse or a rectangle. Moreover, in the said embodiment, although the gas flow path 121 was circular shape, the shape of the gas flow path 121 is not limited to this, For example, elliptical shape and a rectangular shape may be sufficient.

Modification 4
In the above embodiment, the upper surface of the manifold body 21 is open and the upper surface of the manifold body 21 is sealed by the upper wall 22, but the configuration of the manifold 2 is not limited to this.

  For example, as shown in FIG. 17, the manifold body 21 may have a configuration in which the lower surface is open and the bottom wall 23 seals the lower surface of the manifold body 21. In this case, the manifold body 21 has an upper wall 22, a pair of first side walls 24, and a pair of second side walls 25. The manifold body 21 may have a second flange portion 29. The second flange portion 29 extends outward from the lower end portions of the first side wall 24 and the second side wall 25.

  The inner surface of the fourth boundary portion 20d between the upper wall 22, the first side wall 24, and the second side wall 25 has an R shape. The radius of curvature of the inner surface of the fourth boundary portion 20d can be about 2 to 20 mm. The inner side surface of the fourth boundary portion 20d is a surface facing the internal space of the manifold 2.

  The inner side surface of the fifth boundary portion 20e between the first side wall 24 and the second side wall 25 and the second flange portion 29 has an R shape. The radius of curvature of the inner surface of the fifth boundary portion 20e can be about 1 to 10 mm. The inner side surface of the fifth boundary portion 20e is a surface that faces the internal space of the manifold 2.

  As shown in FIG. 18, a second gap 30 is formed between the fifth boundary portion 20 e and the bottom wall 23 in the height direction (x-axis direction) of the internal space of the manifold 2. That is, while the upper surface of the bottom wall 23 and the lower surface of the second flange portion 29 are in contact, the upper surface of the bottom wall 23 and the inner surface of the fifth boundary portion 20e are not in contact. The second gap 30 is formed over the entire circumference.

  As shown in FIG. 17, the bottom wall 23 is disposed on the manifold body 21 so as to close the lower surface of the manifold body 21. Specifically, the bottom wall 23 is fixed to the second flange portion 29. In order to seal the internal space of the manifold 2, the bottom wall 23 is joined to the manifold body 21 over the entire circumference. For example, the bottom wall 23 and the manifold body 21 are joined by crystallized glass. The bottom wall 23 can be formed from at least one of the materials of the manifold body 21 described above.

  The present invention will be described more specifically with reference to the following examples and comparative examples. In addition, this invention is not limited to the following Example.

  Sample no. 1-No. 64 fuel cell stacks were prepared.

  The manifold 2 of each sample was produced by pressing so as to have a rectangular parallelepiped internal space. Table 1 shows the distances L3 and L4 in each sample. The introduction pipe 201 is in contact with the center of the outer surface of the first side wall 24 as shown in FIG.

  Ten fuel cells 1 were attached to the upper wall 22 of the manifold 2 manufactured as described above. The width direction of the fuel battery cell 1 was parallel to the width direction of the manifold 2. The respective fuel cells 1 were arranged at equal intervals in the depth direction of the manifold 2.

  Each fuel cell 1 has a plurality of gas flow paths 121 with an interval of about 2 mm. The gas flow paths 121 are formed at equal intervals in the width direction of the support substrate 12. The gas flow paths 121 formed at both ends in the width direction of each fuel battery cell 1 are arranged so as to correspond to the ends in the width direction of the internal space of the manifold 2. In plan view, the gas flow paths 121 are evenly arranged with respect to the internal space of the manifold 2. That is, each gas flow path 121 is disposed over the entire width direction of the fuel battery cell 1. Other configurations are basically the same between the samples.

Each sample produced as described above was evaluated as follows.
Fuel gas is supplied through the manifold 2 and air is supplied to both sides of each fuel cell 1. The fuel gas used was 62 ° C. humidified hydrogen.
・ Temperature: 750 ℃
Current density: 0.003 A / mm ² energization (Note that the current density is a value relative to the measurement result of the air electrode area formed on the xy plane when viewed from the z-axis direction.)
・ Fuel utilization rate: 80%
The fuel utilization rate is the ratio of the total amount of fuel gas consumed by each power generation element unit 11 during power generation to the amount of fuel gas supplied. Each fuel cell 1 has five power generation element portions 11 arranged at intervals in the longitudinal direction. The dimensions in the longitudinal direction of the power generation element portion 11 were all the same. Appearance observation of the sample generated for 1 hour under the above conditions and cross-sectional microstructure observation by SEM were performed. For comparison, the same observation was performed on samples of the same size that were not subjected to power generation.

The sample in which cracks were confirmed in the sample after power generation was marked with ×, the sample in which microstructural changes were confirmed among the samples that were not confirmed was marked with ◯, and the samples in which neither cracks or microstructural changes were confirmed were marked with ◎. The evaluation results are shown in Table 1. In addition, all the confirmed cracks started from the flow path 121a closest to the gas inlet 241. Further, the microstructural change was confirmed at the air electrode in the vicinity of the downstream side of the fuel cell 1 (the upper end portion of the fuel cell) disposed farthest from the gas inlet 241. From Table 1, it was found that the occurrence of cracks is reduced by setting the first angle θ1 to 77 ° or less. It was also found that the microstructure change can be suppressed by setting the first angle θ1 to 13 ° or more.

Next, the sample No. 1 in which the dimension of the distance L2 was changed after the first angle θ1 satisfied 13 to 77 °. 33-64. 1 to 32, and the same procedure was used.

  Each produced sample was observed for 1 hour after power generation at a fuel utilization rate of 85%. For power generation and observation conditions other than the fuel utilization rate, see sample no. It was the same as in the 1st to 32nd tests. After power generation, the sample in which the microstructural change was confirmed in the fuel cell 1 was marked with ◯, and the sample that was not confirmed was marked with. The evaluation results are shown in Table 2. A test at a fuel utilization rate of 80% was performed in the same manner, but no change was confirmed in all samples. The microstructural change confirmed after the test at a fuel utilization rate of 85% was confirmed at the air electrode near the downstream of the fuel cell 1 disposed at the position farthest from the gas inlet 241. From Table 2, it was found that the microstructural change of the fuel cell 1 can be suppressed by setting the second angle θ2 to 85 ° or more.

DESCRIPTION OF SYMBOLS 1 Fuel cell 121 Gas flow path 2 Manifold 22 Upper wall 23 Bottom wall 24 1st side wall 241 Gas introduction port 25 2nd side wall 26 1st flange part (theta) 1 1st angle (theta) 2 2nd angle

Claims (14)

Manifold,
At least one fuel cell attached to the manifold;
With
The at least one fuel battery cell has a plurality of gas flow paths as a whole,
The manifold is
The bottom wall,
A side wall having a gas inlet opening in a first direction and extending upward from the bottom wall;
An upper wall to which each of the fuel cells is attached;
Have
A line connecting the center of the lower end surface of the gas channel closest to the gas inlet and the center of the gas inlet among the gas channels, and a plane passing through the center of the gas inlet and parallel to the bottom wall The first angle formed with is 77 ° or less,
Fuel cell stack.
The first angle is 13 ° or more.
The fuel cell stack according to claim 1.
The fuel cell includes a plurality of the fuel cells,
The proximal fuel cell closest to the gas inlet has a plurality of the gas flow paths arranged at intervals in a second direction orthogonal to the first direction and extending in the horizontal direction,
Of each gas flow path of the proximal fuel cell, the second angle formed by each line connecting the center of the lower end surface of each gas flow path located on the outermost side in the second direction and the center of the gas introduction port is: 85 ° or more,
The fuel cell stack according to claim 1 or 2.
The fuel cell includes a plurality of the fuel cells,
At least some of the plurality of gas flow paths are disposed at intervals from each other in a second direction orthogonal to the first direction and extending in the horizontal direction,
Of the gas flow paths that are spaced apart from each other in the second direction, each line that connects the center of the lower end surface of each gas flow path that is outermost in the second direction and the center of the gas inlet port The second angle formed is 85 ° or more,
The fuel cell stack according to claim 1 or 2.
Manifold,
A fuel cell having a gas flow path and attached to the manifold;
With
The manifold is
The bottom wall,
A side wall having a gas inlet opening in a first direction and extending upward from the bottom wall;
An upper wall to which each of the fuel cells is attached;
Have
A first angle formed by a line connecting the center of the lower end surface of the gas flow path and the center of the gas inlet and a plane passing through the center of the gas inlet and parallel to the bottom wall is 77 ° or less. ,
Fuel cell stack.
The side wall
A pair of first side walls facing each other in the first direction;
A pair of second side walls facing each other in a second direction orthogonal to the first direction and extending in the horizontal direction ;
Have
The inner side surface of the first boundary portion between the first side wall and the second side wall is R-shaped.
The fuel cell stack according to any one of claims 1 to 5.
The inner side surface of the second boundary portion between the bottom wall and the side wall has an R shape.
The fuel cell stack according to any one of claims 1 to 6.
The manifold further includes a first flange portion extending outward from the side wall,
The upper wall is fixed to the first flange portion.
The fuel cell stack according to any one of claims 1 to 7.
The inner side surface of the third boundary portion between the side wall and the first flange portion has an R shape.
The fuel cell stack according to claim 8.
A first gap is formed between the third boundary and the upper wall;
The fuel cell stack according to claim 9.
The inner surface of the fourth boundary portion between the upper wall and the first and second side walls is R-shaped.
The fuel cell stack according to claim 6 .
The manifold further includes a second flange portion extending outward from lower ends of the first side wall and the second side wall,
The bottom wall is fixed to the second flange portion;
The fuel cell stack according to claim 6 or 11 .
An inner surface of a fifth boundary portion between the first side wall and the second side wall and the second flange portion has an R shape.
The fuel cell stack according to claim 12.
A second gap is formed between the fifth boundary and the bottom wall;
The fuel cell stack according to claim 13.

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