JP2018088358A - Fuel cell stack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel cell stack that can reduce a difference in temperature between fuel cells.SOLUTION: A fuel cell stack 100 comprises: a plurality of fuel cells 1; a plurality of flow rate adjustment members 2; and a manifold 3. The fuel cells 1 are arranged in an arrangement direction and have fuel gas passages 11. The flow rate adjustment members 2 are attached to the leading end parts 5 of the fuel cells 1. The manifold 3 supports the base end parts 4 of the fuel cells 1. The interval Sa between two central part flow rate adjustment members 2a attached to two central part fuel cells 1a located at the central part in the arrangement direction is larger than the interval Sb between two end part flow rate adjustment members 2b attached to two end part fuel cells 1b located at the end parts in the arrangement direction.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a fuel cell stack.

  Conventionally, as a kind of fuel cell stack, a fuel cell stack including a plurality of fuel cells arranged in a row and a manifold that supports a base end portion of each fuel cell is known (for example, see Patent Document 1). .

  A fuel gas flow path is formed inside each fuel cell, and when the fuel cell stack is operated, fuel gas (for example, hydrogen) is supplied from the inside of the manifold to the fuel gas flow path of each fuel cell, An oxygen-containing gas (for example, air) is supplied to the outside of each fuel cell.

Japanese Patent Laying-Open No. 2015-187995

  Here, during operation of the fuel cell stack, a fuel cell located at the center in the arrangement direction (hereinafter referred to as “center part fuel cell”) and a fuel cell located at the end in the arrangement direction (hereinafter referred to as “end part”). A temperature difference is easily generated between the fuel cell and the fuel cell. The viscosity of the fuel gas flowing through the fuel gas flow path of the fuel cell having a high temperature tends to be higher than the viscosity of the fuel gas flowing through the fuel gas flow path of the fuel cell having a low temperature. The flow rate will decrease.

  The present invention has been made in view of the above-described situation, and an object thereof is to provide a fuel cell stack capable of suppressing a temperature difference between fuel cells.

  The fuel cell stack includes a plurality of fuel cells, a plurality of flow rate adjusting members, and a manifold. The plurality of fuel cells are arranged in the arrangement direction and have fuel gas flow paths. The plurality of flow rate adjusting members are attached to the front ends of the plurality of fuel cells. The manifold supports the base end portion of each of the plurality of fuel cells. Among the plurality of flow rate adjustment members, the first interval between the two flow rate adjustment members attached to the two fuel cells located at the center portion in the arrangement direction is equal to two of the plurality of flow rate adjustment members located at the end portions in the arrangement direction. This is different from the second distance between the two flow rate adjusting members attached to the fuel cell.

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

Side view of fuel cell stack A perspective view of a fuel cell to which a flow rate adjusting member is attached A perspective view of a fuel cell to which a flow rate adjusting member is attached

(Fuel cell stack 100)
FIG. 1 is a side view of the fuel cell stack 100. The fuel cell stack 100 includes a plurality of fuel cells 1, a plurality of flow rate adjusting members 2, and a manifold 3.

  The plurality of fuel cells 1 are arranged in the arrangement direction. Each fuel cell 1 is formed in a flat plate shape. In the present embodiment, 18 fuel cells 1 are provided, but the number of fuel cells 1 can be changed as appropriate.

  Each fuel cell 1 has a fuel gas flow path 11 therein. The fuel gas channel 11 extends in the longitudinal direction of the fuel cell 1. During operation of the fuel cell stack 100, fuel gas (for example, hydrogen) is supplied from the inside of the manifold 3 to the fuel gas passage 11 of each fuel cell 1, and an oxygen-containing gas (for example, for example, outside the fuel cell 1). Air).

  The base end portion 4 of each fuel cell 1 is fixed to the manifold 3. The tip 5 of each fuel cell 1 is a free end. Thus, each fuel cell 1 is supported by the manifold 3 in a cantilever state.

  A pair of conductive members 6 are arranged on the outer side in the arrangement direction of the plurality of fuel cells 1. The base end portion of each conductive member 6 is supported by the manifold 3. In the present embodiment, each conductive member 6 is formed in a plate shape, but is not limited thereto. Each conductive member 6 is connected to a current drawing line 6a for drawing current.

  A current collecting member 7 is disposed between each fuel cell 1 and between the fuel cell 1 and the conductive member 6. The current collecting member 7 electrically connects the fuel cells 1 to each other and the fuel cell 1 and the conductive member 6. The current collecting member 7 only needs to be configured so as not to hinder the flow of the oxygen-containing gas flowing between the two adjacent fuel cells 1 from the base end portion 4 side toward the tip end portion 5 side. The shape of 7 is not particularly limited.

  Each flow rate adjusting member 2 is attached to the front end portion 5 of each fuel cell 1. Each flow rate adjusting member 2 is a member for adjusting the flow rate of the oxygen-containing gas that flows between the two adjacent fuel cells 1 from the base end portion 4 side toward the tip end portion 5 side. An oxygen-containing gas flow path through which the oxygen-containing gas passes is formed between the two flow rate adjusting members 2. The interval between the flow rate adjusting members 2 will be described later. In the present embodiment, 18 flow rate adjusting members 2 are provided, but the number of flow rate adjusting members 2 can be appropriately changed according to the number of fuel cells 1.

  Each flow rate adjusting member 2 has a fuel gas discharge passage 21 therein. The fuel gas discharge path 21 is connected to the fuel gas flow path 11 of the fuel cell 1. Of the fuel gas flowing through the fuel gas passage 11, surplus fuel gas that has not been used for power generation is discharged from the fuel gas discharge passage 21 to the outside. Excess fuel gas discharged from the fuel gas discharge passage 21 reacts with the oxygen-containing gas and burns.

  The manifold 3 supports the base end portion 4 of each fuel cell 1. The manifold 3 is configured to distribute the fuel gas to the fuel gas channel 11 of each fuel cell 1. The manifold 3 is a hollow box and has an internal space. Fuel gas is supplied to the internal space of the manifold 3 from a fuel gas supply source (not shown).

(Interval between each flow rate adjusting member 2)
As shown in FIG. 1, the plurality of fuel cells 1 includes a central fuel cell 1a, an end fuel cell 1b, and an intermediate fuel cell 1c.

  The center part fuel cell 1a is the fuel cell 1 arranged in the center part in the arrangement direction among the plurality of fuel cells 1. The central portion in the arrangement direction includes the center in the arrangement direction and the vicinity thereof. Specifically, the fuel cell 1 arranged in a region about ¼ of the total length of the plurality of fuel cells 1 in the arrangement direction with the center in the arrangement direction as the center can be used as the central fuel cell 1a. As shown in FIG. 1, in the present embodiment, four central fuel cells 1a are provided. The number of central fuel cells 1a depends on the total length of the plurality of fuel cells 1 and the size of each fuel cell 1. It can be appropriately changed depending on

  The end fuel cell 1b is a fuel cell 1 arranged at an end in the arrangement direction among the plurality of fuel cells 1. The ends in the arrangement direction include both ends in the arrangement direction and the vicinity thereof. Specifically, the fuel cell 1 arranged in a region from both ends in the arrangement direction to about ¼ of the total length of the plurality of fuel cells 1 can be used as the end fuel cell 1b. As shown in FIG. 1, in the present embodiment, four end fuel cells 1b are provided on both sides of the central fuel cell 1a, but the number of end fuel cells 1b is the same as that of the plurality of fuel cells 1. It can be appropriately changed according to the total length and the size of each fuel cell 1.

  The intermediate part fuel cell 1c is the fuel cell 1 arranged in an intermediate part between the center part and the end part in the arrangement direction among the plurality of fuel cells 1. Specifically, the fuel cell 1 arranged in a region of about 1/8 of the total length of the plurality of fuel cells 1 between the central portion and the end portion in the arrangement direction can be used as the intermediate fuel cell 1c. . As shown in FIG. 1, in the present embodiment, three intermediate fuel cells 1c are provided on both sides of the central fuel cell 1a, but the number of intermediate fuel cells 1c is the same as that of the plurality of fuel cells 1. It can be appropriately changed according to the total length and the size of each fuel cell 1.

  In this embodiment, the size of each fuel cell 1 is substantially the same. That is, the sizes of the central fuel cell 1a, the end fuel cell 1b, and the intermediate fuel cell 1c are substantially the same. Therefore, as shown in FIG. 1, in the arrangement direction, the thickness Pa of the central fuel cell 1a, the thickness Pb of the end fuel cell 1b, and the thickness Pc of the intermediate fuel cell 1c are substantially the same (Pa≈Pb≈Pc). ). Specifically, the thickness Pa, the thickness Pb, and the thickness Pc may be within ± 10% from the arithmetic average value of the thicknesses of all the fuel cells 1. In the present embodiment, “thickness” means the width of each member in the arrangement direction. The thickness of the fuel cell 1 is measured using a digital caliper at a position 50 mm away from the manifold in the longitudinal direction of the fuel cell 1.

  In the present embodiment, the two adjacent fuel cells 1 are arranged at substantially equal intervals in the arrangement direction. Therefore, the interval Qa between the central fuel cells 1a, the interval Qb between the end fuel cells 1b, the interval Qc between the intermediate fuel cells 1c, the interval Qd between the central fuel cell 1a and the intermediate fuel cell 1c, and the intermediate portion The distance Qe between the fuel cell 1c and the end fuel cell 1b is substantially the same (Qa≈Qb≈Qc≈Qd≈Qe). Specifically, the interval Qa, the interval Qb, the interval Qc, the interval Qd, and the interval Qe may be within ± 10% from the arithmetic average value of all intervals of the fuel cell 1. In the present embodiment, the interval between the fuel cells 1 is measured using a digital caliper at a position 50 mm away from the manifold in the longitudinal direction.

  As shown in FIG. 1, the plurality of flow rate adjusting members 2 include a central flow rate adjusting member 2a, an end flow rate adjusting member 2b, and an intermediate flow rate adjusting member 2c.

  The central flow rate adjusting member 2 a is a flow rate adjusting member 2 attached to the central fuel cell 1 a among the plurality of flow rate adjusting members 2. The end flow rate adjusting member 2 b is a flow rate adjusting member 2 attached to the end fuel cell 1 b among the plurality of flow rate adjusting members 2. The intermediate part flow rate adjusting member 2 c is a flow rate adjusting member 2 attached to the intermediate part fuel cell 1 c among the plurality of flow rate adjusting members 2.

  As shown in FIG. 1, in the arrangement direction, the thickness Ra of the central flow rate adjusting member 2a is smaller than the thickness Rb of the end flow rate adjusting member 2b. The thickness Ra of the central flow rate adjusting member 2a is thinner than the thickness Rc of the intermediate flow rate adjusting member 2c. Further, the thickness Rb of the end flow rate adjusting member 2b is thicker than the thickness Rc of the intermediate flow rate adjusting member 2c. Therefore, Ra <Rc <Rb is established. The thickness of the flow rate adjusting member 2 is measured using a digital caliper at the center in the longitudinal direction of the flow rate adjusting member 2.

  Further, as shown in FIG. 1, in the arrangement direction, an interval Sa (an example of a first interval) between two adjacent central flow rate adjusting members 2a is an interval Sb between two adjacent end flow rate adjusting members 2b. It is wider than (an example of the second interval). In the arrangement direction, the interval Sa between the two adjacent central flow rate adjusting members 2a is wider than the interval Sc between the two adjacent intermediate flow rate adjusting members 2c. In the arrangement direction, the interval Sb between two adjacent end flow rate adjusting members 2b is narrower than the interval Sc between two adjacent intermediate flow rate adjusting members 2c. Therefore, Sa> Sc> Sb is established. The thickness of the flow rate adjusting member 2 is measured using a digital caliper at the center of the flow rate adjusting member 2 in the longitudinal direction.

  Here, when the fuel cell stack 100 is operated, each fuel cell 1 releases thermal energy due to Joule heat or reaction heat of the fuel cell 1 itself. At this time, since the end fuel cell 1b has few adjacent fuel cells 1, the thermal energy from the end fuel cell 1b is easily dissipated to the outside, whereas many fuels are present on both sides of the center fuel cell 1a. Since the battery 1 is disposed, the thermal energy from the central fuel cell 1a is less likely to be dissipated outside than the end fuel cell 1b. Therefore, the center fuel cell 1a is likely to be hotter than the end fuel cell 1b.

  Therefore, in the present embodiment, the interval Sa between the central flow rate adjusting members 2a is made wider than the interval Sb between the end flow rate adjusting members 2b. In other words, the interval Sb between the end flow rate adjusting members 2b is narrower than the interval Sa between the two adjacent central flow rate adjusting members 2a. Thereby, the flow rate of the oxygen-containing gas flowing through the gap between the central fuel cells 1a can be made larger than the flow rate of the oxygen-containing gas flowing through the gap between the end fuel cells 1b. Therefore, since the temperature of the center part fuel cell 1a can be lowered and the temperature of the end part fuel cell 1b can be raised, the temperature difference between the center part fuel cell 1a and the end part fuel cell 1b can be reduced. . As a result, the difference in the viscosity of the fuel gas flowing through the fuel gas channel 11 of each of the central fuel cell 1a and the end fuel cell 1b is reduced, so that the fuel gas flow of each of the central fuel cell 1a and the end fuel cell 1b. The flow rate difference of the fuel gas flowing through the passage 11 can be reduced.

  Further, during the operation of the fuel cell stack 100, the intermediate fuel cell 1c is likely to be hotter than the end fuel cell 1b, and is likely to be colder than the central fuel cell 1a.

  Therefore, in the present embodiment, the interval Sc between the intermediate flow rate adjusting members 2c is narrower than the interval Sa between the central flow rate adjusting members 2a and wider than the interval Sb between the end flow rate adjusting members 2b. Yes. Accordingly, the flow rate of the oxygen-containing gas flowing through the gap between the intermediate fuel cells 1c is less than the flow rate of the oxygen-containing gas flowing through the gap between the central fuel cells 1a, and the gap between the end fuel cells 1b is reduced. The flow rate of the flowing oxygen-containing gas can be increased. Therefore, it is possible to reduce the difference in flow rate of the fuel gas flowing through the fuel gas passages 11 of the central fuel cell 1a, the end fuel cell 1b, and the intermediate fuel cell 1c.

(Configuration of fuel cell 1 and flow rate adjusting member 2)
2 and 3 are perspective views of the fuel cell 1 to which the flow rate adjusting member 2 is attached.

  2 and 3, as an example of the fuel cell 1, a so-called horizontal stripe type solid oxide fuel cell (SOFC) is illustrated.

  The fuel cell 1 includes a porous support substrate 10, a plurality of power generation units 20, and a dense seal film 30.

  The porous support substrate 10 is formed in a flat plate shape extending in the longitudinal direction. Six fuel gas passages 11 are formed inside the porous support substrate 10.

The porous support substrate 10 is made of a porous material having low electron conductivity. The porous support substrate 10 includes, for example, CSZ (calcia stabilized zirconia), a composite material of MgO (nickel oxide) and YSZ (yttria stabilized zirconia), a composite material of MgO (nickel oxide) and Y ₂ O ₃ (yttria), A composite material of MgO (magnesium oxide) and MgAl ₂ O ₄ (magnesia alumina spinel) can be used. The porous support substrate 10 may contain a transition metal. The porosity of the porous support substrate 10 is not particularly limited, but can be 20% to 60%. The thickness of the porous support substrate 10 is not particularly limited, but can be 1 mm to 10 mm.

  The plurality of power generation units 20 are arranged in the longitudinal direction on the main surface of the porous support substrate 10. The plurality of power generation units 20 may be disposed on both main surfaces of the porous support substrate 10. The number of the power generation units 20 can be changed as appropriate.

  Each power generation unit 20 includes a fuel electrode, a solid electrolyte layer, an air electrode, and an interconnector. The fuel electrode is disposed on the porous support substrate 10. The solid electrolyte layer is disposed between the fuel electrode and the air electrode. The interconnector electrically connects the fuel electrode of the power generation unit 20 and the air electrode of another power generation unit 20 adjacent thereto. Each power generation unit 20 may have a barrier layer disposed between the solid electrolyte layer and the air electrode. Each power generation unit 20 may have an air electrode current collecting layer disposed on the air electrode.

  The dense seal film 30 covers the outer surface of the porous support substrate 10. The dense seal film 30 may be formed integrally with the solid electrolyte layer of each power generation unit 20. The dense seal film 30 is made of a dense material. Examples of the dense material include YSZ, ScSZ, glass, and spinel oxide.

The flow rate adjusting member 2 is attached to the tip portion 5 of the fuel cell 1. The flow rate adjusting member 2 may be fixed to the front end portion 5 of the fuel cell 1 with a bonding material. For example, crystallized glass can be used as the bonding material. As the crystallized glass, for example, SiO ₂ —B ₂ O ₃ based, SiO ₂ —CaO based, or SiO ₂ —MgO based glass can be used.

In the present embodiment, the flow rate adjusting member 2 is a flat dense body. The flow rate adjusting member 2 is made of a dense material. Examples of the dense material include spinel oxides such as MgO, ZrO ₂ , and MgAl ₂ O ₄ , and glass materials such as ferrite-based stainless steel and SiO ₂ —MgO-based materials, but are not limited thereto. The porosity of the flow rate adjusting member 2 is preferably 20% or less, and more preferably 5% or less.

  The flow rate adjusting member 2 has six fuel gas discharge paths 21 inside. Each fuel gas discharge passage 21 is connected to the fuel gas passage 11 of the fuel cell 1. Each fuel gas discharge path 21 extends in the longitudinal direction of the fuel cell 1.

(Other embodiments)
The present invention is not limited to the embodiment described above, and various modifications or changes can be made without departing from the scope of the present invention.

  In the above embodiment, the case where the flow rate adjusting member according to the present invention is applied to the horizontal stripe type fuel cell 1 has been described. However, the flow rate adjusting member according to the present invention can also be applied to a so-called vertical stripe type fuel cell. it can. The vertically striped fuel cell is disposed on a conductive support substrate, a power generation unit (a fuel electrode, a solid electrolyte layer, and an air electrode) disposed on one main surface of the support substrate, and on the other main surface of the support substrate. Interconnector.

In the said embodiment, although the flow volume adjustment member 2 decided to be a flat dense body, it is not restricted to this. The flow rate adjusting member 2 may be a dense film formed on the side surface of the tip portion 5 of the fuel cell 1. Such a dense film can be formed by dip-filming a dense material such as ZrO ₂ , SiO ₂ —MgO-based crystallized glass on the side surface of the tip portion 5.

  In the above embodiment, as shown in FIG. 1, the plurality of flow rate adjustment members 2 include the intermediate part flow rate adjustment member 2 c, but may not include the intermediate part flow rate adjustment member 2 c. In this case, instead of the intermediate flow rate adjusting member 2c, the middle flow rate adjusting member 2a may be attached to the intermediate fuel cell 1c, or the end flow rate adjusting member 2b may be attached.

  In the above embodiment, as shown in FIG. 1, the plurality of flow rate adjusting members 2 include the central flow rate adjusting member 2 a, the end flow rate adjusting member 2 b, and the intermediate flow rate adjusting member 2 c. Between the central flow rate adjusting member 2a and the intermediate flow rate adjusting member 2c and / or between the end flow rate adjusting member 2b and the intermediate flow rate adjusting member 2c, the central flow rate adjusting member 2a and the end flow rate adjusting member are provided. One or more replenishment flow rate adjustment members having different thicknesses from the member 2b and the intermediate part flow rate adjustment member 2c may be included.

  When the replenishment flow rate adjusting member is disposed between the central part flow rate adjusting member 2a and the intermediate part flow rate adjusting member 2c, it may be attached to either the central part fuel cell 1a or the intermediate part fuel cell 1c. In this case, the thickness of the replenishment flow rate adjusting member is preferably larger than the thickness Ra of the central flow rate adjusting member 2a, and more preferably smaller than the thickness Rc of the intermediate flow rate adjusting member 2c.

  When the replenishment flow rate adjusting member is disposed between the end flow rate adjusting member 2b and the intermediate flow rate adjusting member 2c, it may be attached to either the end fuel cell 1b or the intermediate fuel cell 1c. In this case, the thickness of the replenishment flow rate adjusting member is preferably smaller than the thickness Rb of the end flow rate adjusting member 2b, and more preferably larger than the thickness Rc of the intermediate flow rate adjusting member 2c.

  In the above embodiment, as shown in FIG. 1, the plurality of flow rate adjusting members 2 include three types of flow rate adjusting members (a central flow rate adjusting member 2a, an end flow rate adjusting member 2b, and an intermediate flow rate adjusting member 2c). However, it is not limited to this. For example, the thicknesses of the plurality of flow rate adjusting members 2 may be different, and the flow rate adjusting members 2 may be arranged so that the thickness decreases in order from the end in the arrangement direction toward the center.

DESCRIPTION OF SYMBOLS 1 Fuel cell 1a Center part fuel cell 1b End part fuel cell 1c Middle part fuel cell 2 Flow rate adjustment member 2a Center part flow rate adjustment member 2b End part flow rate adjustment member 2c Middle part flow rate adjustment member 100 Fuel cell stack

Claims (6)

A plurality of fuel cells arranged in the arrangement direction and having fuel gas flow paths;
A plurality of flow rate adjusting members attached to the tip of each of the plurality of fuel cells;
A manifold that supports a base end portion of each of the plurality of fuel cells;
With
Among the plurality of flow rate adjusting members, a first interval between two flow rate adjusting members attached to two fuel cells located in the central portion in the arrangement direction is at an end of the plurality of flow rate adjustment members in the arrangement direction. Different from the second interval between the two flow rate adjusting members attached to the two located fuel cells,
Fuel cell stack. The first interval is wider than the second interval;
The fuel cell stack according to claim 1. The plurality of fuel cells are arranged at substantially equal intervals in the arrangement direction.
The fuel cell stack according to claim 1 or 2. The thickness of each of the plurality of fuel cells is substantially the same.
The fuel cell stack according to any one of claims 1 to 3. Each of the plurality of flow rate adjusting members is a plate-like dense body having a fuel gas discharge passage connected to the fuel gas passage.
The fuel cell stack according to any one of claims 1 to 4. Each of the plurality of flow rate adjusting members is a dense film formed on a side surface of the tip portion.
The fuel cell stack according to any one of claims 1 to 4.

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