JP6188267B1 - Fuel cell stack and manifold - Google Patents

Abstract

A short circuit through a manifold is prevented. A fuel cell stack includes a manifold, a plurality of fuel cells, and a bonding material. The manifold 2 has a manifold body 21 and a top plate 22. The manifold body 21 has an internal space. The top plate 22 closes the upper surface of the manifold body 21. The top plate 22 is made of insulating ceramics. Each fuel cell 1 extends upward from the top plate 22. The bonding material 3 bonds the manifold 2 and the fuel battery cell 1 together. [Selection] Figure 1

Description

  The present invention relates to a manifold and a fuel cell stack.

  The fuel cell stack includes a manifold and a plurality of fuel cells (Patent Document 1). The manifold has a plurality of through holes. Each fuel cell extends upward from the manifold. Specifically, the lower end portion of the fuel battery cell is inserted into the through hole of the manifold, and the fuel battery cell is fixed to the manifold by a bonding material.

  Each fuel cell is electrically connected through a current collecting member. Then, current from each electrically connected fuel cell flows to an external circuit.

Japanese Patent Laying-Open No. 2015-164094

  In the fuel cell stack configured as described above, each fuel cell may be short-circuited via the manifold. Therefore, an object of the present invention is to prevent a short circuit through the manifold.

  The fuel cell stack according to the first aspect of the present invention includes a manifold, a plurality of fuel cells, and a bonding material. The manifold has a manifold body and a top plate. The manifold body has an internal space. The top plate closes the upper surface of the manifold body. The top plate is made of insulating ceramics. Each fuel cell extends from the top plate. The joining material joins the manifold and the fuel battery cell.

  According to this configuration, since the top plate is formed of insulating ceramics, it is possible to prevent the pair of fuel cells from being short-circuited via the top plate.

  Preferably, the top plate has a plurality of through holes. And the lower end part of each fuel battery cell is inserted in each through-hole.

  Preferably, the top plate has a denseness.

  Preferably, the manifold body has a bottom wall, a side wall extending upward from the periphery of the bottom wall, and a flange portion extending outward from the upper end of the side wall. The top plate is joined to the flange portion.

  The manifold according to the second aspect of the present invention is configured to distribute gas to a plurality of fuel cells. The manifold includes a manifold body and a top plate. The manifold body has an internal space. The top plate has a through hole into which the fuel cell is inserted. The top plate closes the upper surface of the manifold body. The manifold is made of insulating ceramics.

  The fuel cell stack according to the third aspect of the present invention includes a manifold, a plurality of fuel cells, and a bonding material. The manifold has a manifold body and a bottom plate. The manifold body has an internal space. The manifold body is made of insulating ceramics. The bottom plate closes the lower surface of the manifold body. Each fuel cell extends from the manifold body. The joining material joins the manifold and the fuel cell.

  According to this configuration, since the manifold body is formed of insulating ceramics, it is possible to prevent the pair of fuel cells from being short-circuited via the manifold body.

  Preferably, the manifold body has a plurality of through holes. And the lower end part of each fuel battery cell is inserted in each through-hole.

  Preferably, the manifold body has a denseness.

  Preferably, the manifold body has an upper wall, a side wall extending downward from the periphery of the upper wall, and a flange portion extending outward from the lower end of the side wall. The bottom plate is joined to the flange portion.

  According to the present invention, it is possible to prevent a short circuit through the manifold.

The perspective view of a fuel cell stack. Sectional drawing of a fuel cell stack. Sectional drawing of a fuel cell stack. The top view of a top plate. The perspective view of a fuel cell. 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 fuel cell stack 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 manifold 2, a plurality of fuel cells 1, and a first bonding material 3. The first bonding material 3 corresponds to the bonding material of the present invention.

[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 supplied to the internal space of the manifold 2 through the introduction pipe 201. The manifold 2 has a plurality of through holes 26 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 a top plate 22. The manifold body 21 and the top plate 22 are separate members and are joined to each other. The manifold body 21 and the top plate 22 may be integrally formed.

  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 side wall 24, and a flange portion 25. The bottom wall 23 has a rectangular shape in plan view (viewed in the x-axis direction). The side wall 24 extends upward from the peripheral edge of the bottom wall 23. The flange portion 25 is a portion extending outward from the upper end portion of the side wall 24. The flange portion 25 is annular.

  The manifold body 21 is composed of one member. That is, the bottom wall 23, the side wall 24, and the flange part 25 are comprised by one member. For example, the manifold body 21 is formed of a metal having heat resistance. More specifically, the manifold body 21 is formed of at least one selected from the group consisting of ferritic stainless steel, austenitic stainless steel, and Ni-based alloy.

  The top plate 22 is disposed on the manifold body 21 so as to close the upper surface of the manifold body 21. Specifically, the top plate 22 is disposed on the flange portion 25. In order to seal the internal space of the manifold 2, the top plate 22 is joined to the manifold body 21 over the entire circumference. For example, the top plate 22 and the manifold body 21 are joined by crystallized glass.

  As shown in FIG. 4, the top plate 22 has a plurality of through holes 26. Each through hole 26 extends in the width direction (y-axis direction) of the manifold 2. In addition, the through holes 26 are arranged at intervals in the longitudinal direction (z-axis direction) of the manifold 2.

The top plate 22 is made of insulating ceramics. Specifically, the top plate 22 is made of 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) is at least one selected from the group consisting of forsterite).

  The top plate 22 is dense. Specifically, the gas supplied into the manifold 2 has such a high density that it does not leak outside through the top plate 22. For example, the porosity of the top plate 22 is about 10% or less.

[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 top plate 22 of the manifold 2. The lower end portion 101 of the fuel cell 1 is inserted into the through hole 26. In the state where the lower end portion 101 of the fuel cell 1 is inserted into the through hole 26, 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 26. 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 longitudinal direction (z-axis direction) of the manifold 2. 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. 5, the fuel battery 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. 6). 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.

  The support substrate 12 has a plurality of gas flow paths 121 extending in the longitudinal direction of the fuel cell 1 inside. The gas flow path 121 communicates with the internal space of the manifold 2 through the through hole 26 of the manifold 2.

  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 channel 121 is open at both ends in the longitudinal direction of the fuel cell 1.

  As shown in FIG. 6, 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 made of a dense material, has substantially the same shape as the fuel electrode active part 132 in a plan view (viewed in the z-axis direction), and is disposed at substantially the same position as the fuel electrode active part 132. Has been. 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 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 portion 17 includes an interconnector 171 and an air electrode current collector film 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 made 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.

  The air electrode current collector film 172 is disposed so as to extend between the interconnector 171 and the air electrode 15 of the adjacent power generation element portions 11. For example, the air electrode current collector is connected so as to electrically connect the air electrode 15 of the power generating element unit 11 disposed on the left side of FIG. 6 and the interconnector 171 of the power generating element unit 11 disposed on the right side of FIG. A membrane 172 is disposed. The air electrode current collector film 172 is a fired body made of a porous material having electron conductivity.

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

  As shown in FIG. 7, the lower end portion 101 of the fuel battery cell 1 is covered with a dense film 18. Specifically, the dense film 18 covers the support substrate 12. The dense film 18 is electrically connected to the power generation element portion 11 formed on the lower end side. Specifically, the dense film 18 is electrically connected to the electrical connection portion 17. The dense film 18 extends toward the proximal side from between the air electrode current collector film 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. The reaction preventing film 16 constituting the dense film 18 is disposed between the electrolyte 14 and the air electrode current collecting film 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 top plate 22 of the manifold 2. The first joining material 3 joins the lower end portion 101 of the fuel cell 1 and the top plate 22 of the manifold 2. The first bonding material 3 is in contact with the dense film 18. In the state where the fuel cell 1 is fixed to the manifold 2, the through hole 26 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. 8, 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. 9, the lower end portion 101 of each fuel cell 1 of the cell assembly 300 is inserted into each through hole 26 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 cells 1 inserted into the through holes 26 and the top plate 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 26.

  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 battery cell 1 is fixed to the top plate 22 of the manifold 2.

[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 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.

Modification 2
The top plate 22 is itself a porous body and may be coated with a dense film.

Modification 3
In the above-described embodiment, the upper surface of the manifold body 21 is open and the top plate 22 is closed on the upper surface, but the configuration of the manifold 2 is not limited to this. For example, as shown in FIG. 10, the lower surface of the manifold body 21 may be open, and the bottom plate 27 may block the lower surface of the manifold body 21. In this case, the manifold body 21 is made of insulating ceramics. A plurality of through holes 26 are formed in the manifold body 21, and the lower end portion 101 of the fuel cell 1 is inserted into the through holes 26.

  Specifically, the manifold body 21 has an upper wall 28, a side wall 24, and a flange portion 25. The upper wall 28 is formed with the plurality of through holes 26 described above. The side wall 24 extends downward from the peripheral edge of the upper wall 28. The flange portion 25 extends outward from the lower end portion of the side wall 24. The bottom plate 27 is joined to the flange portion 25.

1: Fuel cell 2: Manifold 21: Manifold body 22: Top plate 23: Bottom wall 24: Side wall 25: Flange part 26: Through hole 3: First joining material 100: Fuel cell stack 101: Lower end part

Claims (5)

A manifold having a manifold body having an internal space, and a top plate made of insulating ceramics that closes the upper surface of the manifold body;
A plurality of fuel cells extending from the top plate;
A bonding material for bonding the manifold and the fuel battery cell;
A fuel cell stack comprising: The top plate has a plurality of through holes,
The lower end portion of each fuel cell is inserted into each through hole,
The fuel cell stack according to claim 1. The top plate has a denseness,
The fuel cell stack according to claim 1 or 2. The manifold body has a bottom wall, a side wall extending upward from a peripheral edge of the bottom wall, and a flange portion extending outward from an upper end of the side wall,
The top plate is joined to the flange portion.
The fuel cell stack according to any one of claims 1 to 3. A manifold body having an internal space and made of insulating ceramics, and a bottom plate for closing the lower surface of the manifold body;
A plurality of fuel cells extending from the manifold body;
A bonding material for bonding the manifold and the fuel battery cell;
A fuel cell stack comprising:

Images