JP6421166B2 - Fuel cell stack - Google Patents

Description

  The present invention relates to a fuel cell stack.

  The fuel cell stack includes a manifold and a plurality of fuel cells. The manifold is configured to distribute gas to each fuel cell. 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. A gas inlet is formed on the side wall of the manifold. 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.

  Each fuel cell is attached to the upper wall of the manifold. Moreover, each fuel cell is arrange | positioned at intervals in the depth direction. Each fuel cell has a plurality of gas flow paths arranged at intervals in the width direction.

Japanese Patent Laying-Open No. 2015-76339

  In order to stabilize the output of the fuel battery cell, it is preferable to reduce the difference in the amount of gas supplied to each fuel battery cell. However, there is a problem that it is difficult to supply a sufficient amount of gas to each gas flow path of the fuel battery cell arranged closest to the gas inlet. Accordingly, an object of the present invention is to sufficiently supply gas to each gas flow path of the fuel cell arranged closest to the gas inlet.

  A fuel cell stack according to an aspect of the present invention includes a plurality of fuel cells and a manifold. The manifold is configured to distribute gas to each fuel cell. The manifold has a bottom wall, a pair of first side walls, a pair of second side walls, and an upper wall. The pair of first side walls extend upward from the bottom wall and face each other in the depth direction. The pair of second side walls extend upward from the bottom wall and face each other in the width direction. Each fuel cell is attached to the upper wall. One of the pair of first side walls has a gas inlet. Each fuel cell is arranged at intervals in the depth direction. Each fuel cell has a plurality of gas flow paths arranged at intervals in the width direction. The bottom wall, the pair of first side walls, the pair of second side walls, and the top wall define an internal space of the manifold. The ratio (A2 / A1) of the area A2 of the gas inlet to the cross-sectional area A1 of the internal space in the cross section orthogonal to the depth direction is 0.0020 or more.

  According to this configuration, the ratio of the area A2 of the gas introduction port to the cross-sectional area A1 of the internal space is set to 0.0020 or more, so that each gas flow path of the fuel cell arranged closest to the gas introduction port In contrast, the gas can be sufficiently supplied.

  Preferably, the ratio (A2 / A1) of the area A2 of the gas inlet to the cross-sectional area A1 of the internal space is 0.40 or less. According to this structure, it can suppress that the supply amount of the gas with respect to each gas flow path of the fuel battery cell arrange | positioned nearest to the gas introduction port becomes excessive.

  Preferably, the inner side surface of the first boundary portion between the first side wall and the second side wall has an R shape. According to this configuration, the difference in the gas supply amount for each fuel cell can be further reduced.

  Preferably, the inner side surface of the second boundary portion between the bottom wall and the first and second side walls has an R shape. According to this configuration, the difference in the gas supply amount for each fuel cell can be further reduced.

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

  Preferably, the inner surface of the third boundary portion between the first side wall and the second side wall and the first flange portion has an R shape. According to this configuration, the difference in the gas supply amount for each fuel cell can be further reduced.

  Preferably, a first gap portion is formed between the third boundary portion and the upper wall. According to this configuration, the manifold is more easily deformed in the first gap portion than in the manifold not having the first gap portion. For this reason, when the fuel cell is fixed to the manifold with the 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, the difference in the gas supply amount for each fuel cell can be further reduced.

  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, the difference in the gas supply amount for each fuel cell can be further reduced.

  Preferably, a second gap portion is formed between the fifth boundary portion and the bottom wall.

  According to the present invention, it is possible to sufficiently supply gas to each gas flow path of the fuel battery cell arranged closest to the gas inlet.

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. 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. This internal space has a rectangular parallelepiped shape, for example.

  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.

  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 at the center of the first side wall 24. Gas is introduced into the internal space of the manifold 2 from this gas inlet. 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.

  As shown in FIG. 4, the ratio (A2 / A1) of the area A2 of the gas inlet 241 to the cross-sectional area A1 of the internal space is 0.0020 or more. Further, the ratio (A2 / A1) of the area A2 of the gas inlet 241 to the cross-sectional area A1 of the internal space is preferably 0.40 or less. The cross-sectional area A1 of the internal space is a cross-sectional area in a cross section orthogonal to the depth direction (z-axis direction). The cross section perpendicular to the depth direction (z-axis direction) is provided with the center of the lower end surface of the gas channel 121 closest to the gas inlet 241 and the gas inlet 241 among the plurality of gas channels 121. It is a cross section which passes through the midpoint in the depth direction of the inner wall surface of the 1st side wall 24. Further, the inner side surface of the first side wall 24 is a surface facing the internal space of the manifold 2.

  The flow rate of the gas introduced into the internal space of the manifold 2 is preferably about 0.010 to 2.5 m / s in terms of 0 ° C. and 1 atm when the fuel cell 1 generates power. The flow velocity can be calculated from the flow rate introduced into the manifold 2 and the cross-sectional area A1 of the internal space.

  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, Ni-based alloy, MgO (magnesium oxide), Al ₂ O ₃ (aluminum oxide), MgAl ₂ O ₄ (magnesia alumina spinel), It is formed of at least one selected from the group consisting of 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 H 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 H is the dimension of the internal space in the direction orthogonal to the depth D and the width W. That is, the height H 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 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. The lower end portion of the fuel cell 1 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 from each other along the depth direction (z-axis direction) of the manifold 2. Further, each fuel cell 1 is arranged such that each main surface faces the depth direction (z-axis direction). In addition, each fuel cell 1 does not need to be arrange | positioned at equal intervals along a longitudinal direction. Moreover, in this embodiment, although each fuel cell 1 is arrange | positioned at 1 row, you may arrange | position at multiple rows. 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. 12). 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 in the width 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. Each gas channel 121 has a circular shape and can have a diameter of about 0.3 to 5.0 mm. The cross-sectional shape of the gas flow path 121 is preferably circular, but may be elliptical. The channel diameter of the gas channel 121 may not be uniform along the longitudinal direction of the support substrate 12.

  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. Moreover, as shown in FIG. 11, the distance L2 between the gas inlet 241 and the center of the lower end surface of the gas flow path 121 in the depth direction is about 1 to 30 mm.

  The ratio of the distance L2 to the distance L1 (L2 / L1) is preferably about 0.15 to 35. By setting this ratio (L2 / L1) within the above range, it is possible to further suppress the local occurrence of a gas retention portion in the internal space of the manifold 2. The distance L1 is the distance in the width direction between the center of the lower end surface of the gas flow path 121 and the inner wall surface of the second side wall 25, the distance from the second side wall 25 being closest in the width direction. Further, the distance L2 is the center of the lower end surface of the gas flow path 121 closest to the gas introduction port 241 among the plurality of gas flow paths 121, and the inner wall surface of the first side wall 24 provided with the gas introduction port 241. Is the distance in the depth direction. Each gas flow path 121 is preferably arranged so as to draw a rectangle basically in a yz plan view, but may be slightly shifted in position.

  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. 12, 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. 12 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. 13, 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 from between the air electrode current collector 172 and the support substrate 12 toward the proximal side.

  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. 14, each fuel cell 1 is connected to each other by the first current collecting member 4 and the second bonding material 5 to produce a 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. 15, 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.

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. 16, 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. 17, a second gap 30 is formed between the fifth boundary 20 e and the bottom wall 22 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. 16, 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.

Modification 5
In the above embodiment, the internal space of the manifold 2 has a rectangular parallelepiped shape, but the shape of the internal space of the manifold 2 is not particularly limited.

  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. 66 fuel cell stacks were produced.

  The manifold of each sample was produced by pressing so as to have a rectangular parallelepiped internal space.

  Tables 1 and 2 show the cross-sectional area A1 of the internal space of each sample, the area A2 of the gas inlet 241 and the ratio A2 / A1. The gas inlet 241 is formed at the center of the first side wall 24, and the inlet tube 201 is in contact with the center of the outer surface of the first side wall 24 as shown in FIG. The cross-sectional area A1 of the internal space and the area A2 of the gas inlet 241 were calculated by reading each cross-section image into CAD software.

  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 at intervals 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 formed at both ends in the width direction of each fuel cell are arranged to correspond to the ends in the width direction of the internal space of the manifold. In plan view, the gas flow paths 121 are evenly arranged with respect to the internal space of the manifold. Moreover, each gas flow path 121 is arrange | positioned over the whole width direction of the fuel cell 1. As shown in FIG. The configuration other than the cross-sectional area A1, the area A2, and the width of each fuel cell 1 was basically the same between the samples.

(Test A)
Sample No. produced as described above. The voltage value of each fuel cell 1 when 1 to 30 was generated for 1 hour under the following conditions was recorded every minute.
・ Fuel gas is supplied through the manifold 2 and air is supplied to both sides of the fuel cell 1 ・ Temperature: 750 ° C.
Current density: 0.003 A / mm ² energization (Note that the current density is a value for the measurement result of the air electrode area of one power generation element portion 11 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. And the sample which had the fuel cell 1 in which the standard deviation of the voltage measurement result for every 1 minute of each fuel cell 1 exceeded 2.0 was made into x, and the sample which did not exist was made into (circle). In addition, since all the standard deviations of the voltage measurement values when evaluating each fuel battery cell 1 by one became 2.0 or less, the variation derived from the measuring device is small. The evaluation results are shown in Table 1. When the ratio A2 / A1 is smaller than 0.0020, the standard deviation of the voltage measurement result exceeds 2.0 in the fuel cell 1 attached at the closest position to the gas inlet 241. On the other hand, when the ratio A2 / A1 is greater than 0.40, the standard deviation exceeds 2.0 in the fuel cell 1 that is mounted farthest from the gas inlet 241.

  From the above, by setting the ratio A2 / A1 to be 0.0020 or more, the gas can be sufficiently supplied to each gas flow path 121 of the fuel cell 1 disposed closest to the gas introduction port 241. I understand. Further, by setting the ratio A2 / A1 to 0.40 or less, it is possible to suppress an excessive amount of gas supply to each gas flow path 121 of the fuel cell 1 disposed closest to the gas introduction port 241. I understand that.

(Test B)
Sample No. with a ratio (A2 / A1) of 0.000020 to 0.40. The same test as Test A was performed on 31-66 at a fuel utilization rate of 80% and 85%. And the sample that had a cell with a standard deviation of more than 2.0 at a fuel utilization rate of 80%, and the sample that had a cell with a standard deviation of more than 2.0 at a fuel utilization rate of 85% were marked with a standard deviation. Samples with an A of 2.0 or less were marked with ◎. In each sample tested this time, 10 fuel cells are arranged so that the values of the distance L1 are all equal. Sample No. The ratios (L2 / L1) of 1 to 30 were all 10. The above evaluation results are shown in Table 2. In all the samples, the standard deviation of the fuel utilization rate of 85% is 80%, which is larger than that during power generation. As can be seen from Table 2, by setting the ratio (L2 / L1) to 0.15 to 35, the manifold 2 It was possible to suppress the occurrence of a local gas retention part.

DESCRIPTION OF SYMBOLS 1 Fuel cell 2 Manifold 20a 1st boundary part 20b 2nd boundary part 20c 3rd boundary part 22 Upper wall 23 Bottom wall 24 1st side wall 241 Gas introduction port 25 2nd side wall

Claims (12)

A plurality of fuel cells;
A manifold configured to distribute gas to each of the fuel cells;
With
The manifold is
The bottom wall,
A pair of first side walls extending upward from the bottom wall and facing each other in the depth direction;
A pair of second side walls extending upward from the bottom wall and facing each other in the width direction;
An upper wall to which each of the fuel cells is attached;
Have
One first side wall of the pair of first side walls has a gas inlet,
The plurality of fuel cells have a plurality of gas flow paths that are spaced from each other along the depth direction of the manifold and that are spaced from each other in the depth direction and the width direction. And
The bottom wall, the pair of first side walls, the pair of second side walls, and the top wall define an internal space of the manifold;
The ratio (A2 / A1) of the area A2 of the gas inlet to the cross-sectional area A1 of the internal space in the cross section perpendicular to the depth direction is 0.0020 or more.
Fuel cell stack.
The ratio (A2 / A1) of the area A2 of the gas inlet to the cross-sectional area A1 of the internal space is 0.40 or less.
The fuel cell stack according to claim 1.
Closest to the gas inlet and the gas inlet with respect to the distance L1 in the width direction between the center of the lower end surface of the gas flow path 121 disposed at both ends in the width direction and the inner wall surface of the second side wall 25 The ratio (L2 / L1) of the distance L2 in the depth direction to the center of the lower end surface of the gas flow path is 0.15 to 35.
The fuel cell stack according to claim 1 or 2.
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 3.
The inner side surface of the second boundary portion between the bottom wall and the first and second side walls is R-shaped.
The fuel cell stack according to any one of claims 1 to 4.
The manifold further includes a first flange portion extending outward from the first side wall and the second side wall;
The upper wall is fixed to the first flange portion.
The fuel cell stack according to any one of claims 1 to 5.
The inner side surface of the third boundary portion between the first side wall and the second side wall and the first flange portion has an R shape.
The fuel cell stack according to claim 6.
A first gap is formed between the third boundary and the upper wall;
The fuel cell stack according to claim 7.
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 any one of claims 1 to 8.
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 any one of claims 1 to 9.
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 10.
A second gap is formed between the fifth boundary and the bottom wall;
The fuel cell stack according to claim 11.

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