fuel cell

Abstract

This technology provides a way to suppress damage to power generation equipment. [Solution] The fuel cell cell comprises a pair of separators arranged along both sides of the power generator, the first separator having a first body portion and a first bead seal portion protruding from the first body portion toward the power generator, and the second separator having a second body portion and a second bead seal portion protruding from the second body portion toward the power generator. The first bead seal portion has a first inclined portion, a second inclined portion longer than the first inclined portion, and a first surface portion located between the first and second inclined portions and in contact with the power generator. The second bead seal portion has a third inclined portion facing the first inclined portion, a fourth inclined portion facing the first inclined portion and shorter than the third inclined portion, and a second surface portion located between the third and fourth inclined portions and in contact with the power generator.

Description

Technical Field

[0001] The present disclosure relates to fuel cell.

Background Art

[0002] There is known a fuel cell in which a power generation body having an electrolyte membrane is sandwiched by a pair of separators in which bead seal portions protruding toward the power generation body are formed. Patent Document 1 describes a separator having bead seal portions configured such that embossed shapes are provided so as to be offset from each other.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When a power generation body and a separator are laminated and a fastening load is applied in the lamination direction, stress concentrates at the end of the bead seal portion in contact with the power generation body, and there is a risk that the power generation body may be damaged.

Means for Solving the Problems

[0005] The present disclosure has been made to solve the above problems and can be realized in the following forms.

[0006] A fuel cell is provided according to an embodiment of the present disclosure. The fuel cell is a pair of separators arranged along both sides of a power generator, comprising: a first separator having a first body portion and a first bead seal portion projecting from the first body portion toward the power generator; and a second separator having a second body portion and a second bead seal portion projecting from the second body portion toward the power generator. The first bead seal portion has a first inclined portion, a second inclined portion longer than the first inclined portion, and a first surface portion located between the first and second inclined portions and in contact with the power generator. The second bead seal portion has a third inclined portion facing the first inclined portion, a fourth inclined portion facing the first inclined portion and shorter than the third inclined portion, and a second surface portion located between the third and fourth inclined portions and in contact with the power generator. In this type of fuel cell, because the lengths of the inclinations of the opposing bead seal sections are asymmetrical, when a load is applied in the stacking direction between the separator and the power generator, the second and third inclined sections deform before the first and fourth inclined sections. Therefore, bending of the first and second surfaces can be suppressed. Consequently, damage to the power generator can be suppressed.

[0007] Furthermore, this disclosure can be implemented in various forms, for example, as a separator for fuel cell cells, a fuel cell stack comprising multiple stacked fuel cell cells, or a method for manufacturing fuel cell cells. [Brief explanation of the drawing]

[0008] [Figure 1] This is an explanatory diagram showing a disassembled fuel cell. [Figure 2] This is a cross-sectional view showing the schematic structure of a fuel cell cell. [Modes for carrying out the invention]

[0009] A. First Embodiment: Figure 1 is an explanatory diagram showing an exploded view of a fuel cell cell 100 in one embodiment of the present disclosure. Figure 2 is a cross-sectional view taken along the line II-II in Figure 1 of a stack of fuel cell cells 100s. More specifically, it is a cross-sectional view taken in a direction intersecting the direction in which the first bead seal portion 22 and the second bead seal portion 32, which will be described later, extend. The fuel cell cell 100 is a solid polymer fuel cell that generates electricity by receiving hydrogen, which is the cathode gas, and oxygen, which is the anode gas, as reaction gases. The fuel cell cell 100 comprises a power generation unit 10, a first separator 20, and a second separator 30.

[0010] The power generation unit 10 is a component formed by joining the power generation unit 11 and the frame member 12. The power generation unit 11 is positioned and joined to the central hole 13 of the frame member 12.

[0011] The power generation unit 11 comprises an electrolyte membrane (not shown), catalyst layers (not shown) formed adjacent to both sides of the electrolyte membrane, and a gas diffusion layer (not shown) formed adjacent to one side of the catalyst layer. The electrolyte membrane is a solid polymer thin film that exhibits good proton conductivity in a wet state. The electrolyte membrane is composed of, for example, an ion exchange membrane made of a fluororesin. The catalyst layer comprises a catalyst that promotes the chemical reaction between hydrogen and oxygen, and carbon particles supporting the catalyst. The electrolyte membrane and catalyst layer together are also called a membrane electrode assembly (MEA).

[0012] The gas diffusion layer is provided adjacent to one of the catalyst layers. The gas diffusion layer diffuses the reaction gas used in the electrode reaction along the plane of the electrolyte membrane and is composed of a porous diffusion layer substrate. As the diffusion layer substrate, porous substrates with conductivity and gas diffusion properties such as carbon fiber substrates, graphite fiber substrates, and foamed metals are used. This electrolyte membrane, catalyst layer, and gas diffusion layer together are also called a membrane electrode gas diffusion layer assembly (MEGA).

[0013] In this embodiment, the frame member 12 is an insulating sheet made of resin. A sealing member 14 is provided in a substantially rectangular shape on the periphery of the surface of the frame member 12. The sealing member 14 is provided in a position opposite to the first bead seal portion 22 and the second bead seal portion 32, which will be described later.

[0014] A pair of first separators 20 and second separators 30 are arranged along both sides of the power generator 10. The first separators 20 and second separators 30 are formed, for example, by press-forming metal sheets made of stainless steel, titanium, or an alloy thereof.

[0015] The first separator 20 has a first main body portion 21 and a first bead seal portion 22 that protrudes from the first main body portion 21 toward the power generator 10. In this embodiment, the first bead seal portion 22 is formed in a substantially rectangular shape on the peripheral edge of the surface of the first separator 20. The peripheral edge of the first bead seal portion 22 is the region near the inner side of the outer peripheral edge of the first bead seal portion 22. The first bead seal portion 22 has a first surface portion 23, a first inclined portion 24, and a second inclined portion 25.

[0016] In this embodiment, the first surface portion 23 is a plane in contact with the power generation body 10. The first surface portion 23 is located between the first inclined portion 24 and the second inclined portion 25. The first inclined portion 24 is a plane that is continuous from one end of the first surface portion 23. The second inclined portion 25 is a plane that is continuous from the other end of the first surface portion 23.

[0017] The inclination direction of the first inclined portion 24 and the inclination direction of the second inclined portion 25 are configured to intersect on the power generation body 10 side in the protruding direction of the first bead seal portion 22, when each is virtually extended. The length L2 of the second inclined portion 25 in the direction in which the first surface portion 23, the first inclined portion 24, and the second inclined portion 25 are connected (hereinafter also referred to as the "width direction") is longer than the length L1 of the first inclined portion 24 in the width direction.

[0018] The second separator 30 has a second main body portion 31 and a second bead seal portion 32 that protrudes from the second main body portion 31 toward the power generation body 10. In the present embodiment, the second bead seal portion 32 is formed in a substantially rectangular shape at the periphery on the surface of the second separator 30. The periphery of the second bead seal portion 32 is a region near the inside of the outer peripheral edge of the second bead seal portion 32. The second bead seal portion 32 has a second flat portion 33, a third inclined portion 34, and a fourth inclined portion 35.

[0019] In the present embodiment, the second flat portion 33 is a flat surface that contacts the power generation body 10. The second flat portion 33 is located between the third inclined portion 34 and the fourth inclined portion 35. The third inclined portion 34 is a flat surface that continues from one end of the second flat portion 33. The third inclined portion 34 is located at a position facing the first inclined portion 24. The fourth inclined portion 35 is a flat surface that continues from the other end of the second flat portion 33. The fourth inclined portion 35 is located at a position facing the second inclined portion 25.

[0020] The inclination direction of the third inclined portion 34 and the inclination direction of the fourth inclined portion 35 are configured to intersect on the power generation body 10 side in the protruding direction of the second bead seal portion 32 when virtually extended respectively. The length L4 in the width direction of the fourth inclined portion 35 is shorter than the length L3 in the width direction of the third inclined portion 34. The length L1 and the length L4 are the same length, and the length L2 and the length L3 are the same length. The direction in which the first main body portion 21, the first bead seal portion 22, the first flat portion 23, and the first inclined portion 24 are connected is the same as the direction in which the second main body portion 31, the second bead seal portion 32, the second flat portion 33, and the third inclined portion 34 are connected.

[0021] In the stacking direction of the power generation body 10 and the separators 20, 30, the end portion of the first inclined portion 24 on the first main body portion 21 side coincides with the end portion of the third inclined portion 34 on the second main body portion 31 side. Also, in the stacking direction of the power generation body 10 and the separators 20, 30, the end portion of the second inclined portion 25 on the first main body portion 21 side coincides with the end portion of the fourth inclined portion 35 on the second main body portion 31 side.

[0022] That is, the length of the first bead seal portion 22 in the width direction is the same as the length of the second bead seal portion 32 in the width direction. Therefore, in the direction in which the first surface portion 23 and the second surface portion 33 face each other, the center A0 of the first surface portion 23 and the center A1 of the second surface portion 33 do not coincide. The center A0 is a position where the lengths from one end of the first surface portion 23 in the width direction and from the other end are equal. Also, the center A1 is a position where the lengths from one end of the second surface portion 33 in the width direction and from the other end are equal.

[0023] In the present embodiment, since the lengths of the inclined portions of the opposing bead seal portions 22 and 32 are asymmetrical left and right, when a load is applied in the stacking direction of the power generation body 10 and the separators 20 and 30, the second inclined portion 25 and the third inclined portion 34 deform before the first inclined portion 24 and the fourth inclined portion 35. Therefore, it is possible to suppress the bending of the surface portions 23 and 33. Accordingly, it is possible to suppress damage to the power generation body 10.

[0024] B. Other Embodiments: (B1) In the above-described embodiment, the first surface portion 23, the first inclined portion 24, the second inclined portion 25, the second surface portion 33, the third inclined portion 34, and the fourth inclined portion 35 are all flat surfaces. However, the present invention is not limited to this, and the first surface portion 23, the first inclined portion 24, the second inclined portion 25, the second surface portion 33, the third inclined portion 34, and the fourth inclined portion 35 may be curved surfaces. Also, the first inclined portion 24, the second inclined portion 25, the second surface portion 33, and the third inclined portion 34 may be composed of a plurality of flat surfaces and / or curved surfaces.

[0025] (B2) In the above-described embodiment, the length L1 of the first inclined portion 24 and the length L4 of the fourth inclined portion 35 are the same length, and the length L2 of the second inclined portion 25 and the length L3 of the third inclined portion 34 are the same length. However, the present invention is not limited to this, and the length of the length L1 and the length L4 may be different, and the length of the length L2 and the length L3 may be different.

[0026] (B3) In the embodiment described above, the frame member 12 is an insulating sheet provided with a sealing member 14. However, the frame member 12 may be a member made of pressure-sensitive adhesive, in which the sealing member 14 is omitted.

[0027] This disclosure is not limited to the embodiments described above, and can be implemented in various configurations without departing from its spirit. For example, the technical features in the embodiments corresponding to the technical features in each form described in the summary of the invention can be replaced or combined as appropriate in order to solve the problems described above or to achieve some or all of the effects described above. Furthermore, if a technical feature is not described as essential in this specification, it can be deleted as appropriate. [Explanation of symbols]

[0028] 10...Power generator, 11...Power generation unit, 12...Frame member, 13...Hole, 14...Sealing member, 20...First separator, 21...First main body, 22...First bead seal, 23...First surface, 24...First inclined section, 25...Second inclined section, 30...Second separator, 31...Second main body, 32...Second bead seal, 33...Second surface, 34...Third inclined section, 35...Fourth inclined section, 100...Fuel cell cell

Claims

[Claim 1] It is a fuel cell cell, A pair of separators arranged along both sides of a power generator, comprising: a first separator having a first main body and a first bead seal portion protruding from the first main body toward the power generator; and a second separator having a second main body and a second bead seal portion protruding from the second main body toward the power generator. The first bead seal portion is, The first inclined section and A second inclined portion that is longer than the first inclined portion, It has a first surface portion located between the first inclined portion and the second inclined portion and in contact with the power generation body, The second bead seal portion is, A third inclined portion opposite to the first inclined portion, A fourth inclined portion is located opposite the first inclined portion and is shorter than the third inclined portion, A fuel cell cell having a second surface portion located between the third inclined portion and the fourth inclined portion and in contact with the power generation body.

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