Gasket, fuel cell, and water electrolysis device

Abstract

The present invention provides a gasket, a fuel cell, and a water electrolysis device capable of enhancing the effect of suppressing leakage of a fluid to be sealed even in an environment where the pressure of the fluid to be sealed is high. A gasket (300) is provided with a reinforcing member (310) and a rubber-shaped elastic gasket body (320) integrally installed on the reinforcing member (310). The gasket body (320) integrally comprises a thin section (321) installed to cover a portion of one surface of the reinforcing member (310) along the inner circumference (311b) of the opening, and a thick section (322) installed to protrude toward both sides within the opening. Additionally, the Young's modulus of the reinforcing member (310) is higher than the Young's modulus of the gasket body (320), and if the thickness of the reinforcing member (310) is TF, the thickness of the thin section (321) is TB, and the maximum thickness of the thick section (322) is TG, then 3 < TG / (TF + TB) ≤ 60 is satisfied.

Description

Technology Field

[0001] The present invention relates to a gasket, a fuel cell, and a water electrolysis device. Background Technology

[0003] Fuel cells and water electrolysis devices are generally composed of a membrane unit including an electrolyte membrane and a cell stack having multiple single cells, each having a pair of separators disposed on both sides of the membrane unit. In these devices, a passage for various fluids is formed, and a gasket is installed to suppress fluid leakage from the passage.

[0004] There are various forms of gaskets, such as integrally molding a rubber-shaped elastic body as a gasket into a membrane unit or separator, but there are also many cases where it is required to be used as a separate component from the membrane unit and separator. Referring to FIG. 6, a gasket related to a conventional example will be described. FIG. 6 is a schematic cross-sectional view showing the usage state of a gasket related to a conventional example. FIG. 6 (a) shows a state where no fluid is flowing in the passage, and FIG. 6 (b) shows a state where the pressure of the fluid flowing in the passage is high.

[0005] In the illustrated example, a rubber-shaped elastic gasket (500) is placed between a pair of separators (200). Accordingly, leakage of fluid from the passage can be suppressed. However, as the pressure (P) of the fluid flowing through the passage increases, the gasket (500) deforms to widen toward the side opposite to the fluid to be sealed. Consequently, the gasket (500) deforms to become thinner, and thus the surface pressure on the separator (200) decreases. Therefore, depending on the pressure of the fluid, the fluid may be ejected as indicated by the arrow L in the drawing. Prior art literature

[0007] [Patent Document 1] Japanese Patent Publication No. 2012-117140 The problem to be solved

[0008] The objective of the present invention is to provide a gasket, a fuel cell, and a water electrolysis device capable of enhancing the effect of suppressing leakage of a fluid to be sealed, even in an environment where the pressure of the fluid to be sealed is high. means of solving the problem

[0010] The present invention employs the following means to solve the above problem.

[0011] That is, the gasket of the present invention is,

[0012] A thin plate-shaped reinforcing member having an opening that serves as a passage for a fluid to be sealed, and

[0013] A gasket having a rubber-shaped elastic gasket body integrally installed on the reinforcing member to cover the entire inner surface of the opening, and

[0014] The above gasket body is,

[0015] A thin-walled portion installed to cover a portion of one surface of the above reinforcing member along the inner circumference of the opening, and

[0016] In addition to integrally having a thick portion installed to protrude toward both sides within the above-mentioned opening,

[0017] The Young's modulus of the above reinforcing member is higher than the Young's modulus of the above gasket body, and

[0018] If the thickness of the above reinforcing member is TF, the thickness of the thin section is TB, and the maximum thickness of the thick section is TG,

[0019] 3 < TG / (TF + TB) ≤ 60

[0020] It is characterized by satisfying [the condition].

[0021] According to the present invention, even if the pressure of the fluid to be sealed increases in the thick portion of the gasket body, the gasket body can be prevented from expanding due to the reinforcing member. Accordingly, deformation such as the thick portion becoming thin can be prevented, and the deterioration of sealing performance can be prevented. Furthermore, by setting the relationship of Young's modulus and the relationship of TF, TB, and TG to satisfy the above-mentioned relationship, deformation of the gasket body due to the increase in the pressure of the fluid to be sealed can be effectively prevented.

[0022] The fuel cell of the present invention is,

[0023] A fuel cell having a plurality of single cells, each having a membrane unit including an electrolyte membrane and a pair of separators disposed on both sides of the membrane unit.

[0024] It is characterized by having the above gasket disposed in at least one of the gap between the separators and the gap between the separator and the membrane unit.

[0025] The water electrolysis device of the present invention is,

[0026] A water electrolysis device comprising a membrane unit including an electrolyte membrane and a plurality of single cells each having a pair of separators disposed on both sides of the membrane unit.

[0027] It is characterized by having the above gasket disposed in at least one of the gap between the separators and the gap between the separator and the membrane unit. Effects of the invention

[0029] As explained above, according to the present invention, the effect of suppressing leakage of the fluid to be sealed can be enhanced even in an environment where the pressure of the fluid to be sealed is high. Brief explanation of the drawing

[0031] FIG. 1 is a schematic cross-sectional view showing the main configuration of a fuel cell related to an embodiment of the present invention. FIG. 2 is a schematic cross-sectional view showing the main configuration of a water electrolysis device related to an embodiment of the present invention. FIG. 3 is a plan view of a separator related to an embodiment of the present invention. FIG. 4 is a plan view of a gasket related to an embodiment of the present invention. FIG. 5 is a schematic cross-sectional view of a gasket related to an embodiment of the present invention. FIG. 6 is a schematic cross-sectional view showing the usage state of a gasket related to a conventional example. Specific details for implementing the invention

[0032] Hereinafter, with reference to the drawings, embodiments for carrying out this invention will be described in detail by example based on examples. However, unless specifically stated otherwise, the dimensions, materials, shapes, relative arrangements, etc. of the constituent parts described in these embodiments are not intended to limit the scope of this invention solely to those elements.

[0034] (Example)

[0035] With reference to FIGS. 1 to 5, a gasket, a fuel cell, and a water electrolysis device related to an embodiment of the present invention will be described. FIG. 1 is a schematic cross-sectional view showing the main configuration of a fuel cell related to an embodiment of the present invention. FIG. 2 is a schematic cross-sectional view showing the main configuration of a water electrolysis device related to an embodiment of the present invention. FIG. 3 is a plan view of a separator related to an embodiment of the present invention. In addition, the cross-sectional view of the lower separator in FIG. 1 corresponds to the AA cross-sectional view in FIG. 3. FIG. 4 is a plan view of a gasket related to an embodiment of the present invention. FIG. 5 is a schematic cross-sectional view of a gasket related to an embodiment of the present invention, and FIG. 5(a) corresponds to the BB cross-sectional view in FIG. 4. In addition, FIG. 5(a) shows the state of a gasket unit, and FIG. 5(b) and (c) show parts of a cross-sectional view of a single cell in a state where the gasket is fitted into a fuel cell.

[0037] Fuel Cell

[0038] Referring to FIG. 1, a fuel cell to which a gasket related to the present embodiment can be applied is described. Generally, a fuel cell is configured as a cell stack consisting of a plurality of single cells. FIG. 1 shows a schematic cross-sectional view of a part of a single cell. A single cell is composed of an MEA (100A) (Membrane Electrode Assembly) as a membrane unit and a pair of separators (200A) installed on both sides thereof. In addition, in the cell stack, there are also places where the MEA is not interposed in the part where the coolant flows, and the separators are installed adjacent to each other. The MEA (100A) has an electrolyte membrane (110) and a pair of gas diffusion layers (120, 130) respectively provided on both sides of the electrolyte membrane (110). And, a concave portion (210) that serves as a passage for fluid is installed on the surface of the separator (200A).

[0039] With the above configuration, fuel gas is supplied to one side of the MEA (100A) and oxidizer gas is supplied to the other side, thereby causing a chemical reaction in the electrolyte membrane (110) to generate water and electrons, which can then generate electricity. Additionally, a gasket is installed in the fuel cell to prevent leakage of the fluids to be sealed (fuel gas, oxidizer gas, water, cooling water).

[0041] Electrolytic device

[0042] Referring to FIG. 2, a water electrolysis device to which a gasket related to the present embodiment can be applied will be described. Generally, a water electrolysis device is configured as a cell stack consisting of a plurality of single cells. FIG. 2 shows a schematic cross-sectional view of a part of a single cell. A single cell is composed of a membrane unit (100B) and a pair of separators (200B) installed on both sides thereof. The membrane unit (100B) has an electrolyte membrane (110) and current collectors (140, 150) respectively provided on both sides of the electrolyte membrane (110). Additionally, a concave portion (210) serving as a passage for fluid is installed on the surface of the separator (200A).

[0043] With the above configuration, power is supplied while pure water is supplied into the cell, and the water is decomposed into hydrogen ions and oxygen ions by the electrolyte membrane (110), and water containing oxygen molecules flows on one side of the membrane unit (100B), and water containing hydrogen molecules flows on the other side. In addition, a gasket is installed in the water electrolysis device to suppress leakage of the fluid to be sealed (pure water, water containing oxygen molecules, water containing hydrogen molecules).

[0045] Separator

[0046] In particular, with reference to FIG. 3, the separator will be described in detail. Since the basic configuration of the separator (200A) used in the fuel cell (10A) and the separator (200B) used in the water electrolysis device (10B) are the same, the specific configuration will be described using the separator (200A) as a representative example.

[0047] The separator (200A) is equipped with a recess (210) that serves as a passage for fluid and a plurality of manifolds (referred to as the first manifold (221), the second manifold (222), and the third manifold (223) for supplying fluid to each single cell. For example, fuel gas flows through the first manifold (221), oxidizer gas flows through the second manifold (222), and cooling water flows through the third manifold (223). In this drawing, a configuration is shown in which fluid flowing through the first manifold (221) flows into the recess (210). In the drawing, the thick dashed line (ML) indicates the area facing the MEA (100A) when a single cell is configured. Additionally, in the drawing, a thin dotted line (SL) indicates a seal line to which the gasket (300), described later, adheres. As illustrated, the seal line (SL) is configured to surround the area where a pair of first manifolds (221) and a recess (210) are installed, and to surround the second manifold (222) and the third manifold (223), respectively.

[0049] Gasket

[0050] With reference to FIGS. 4 and 5, the gasket (300) related to the present embodiment will be described in detail. The gasket (300) related to the present embodiment consists of a thin plate-shaped reinforcing member (310) and a gasket body (320) made of a rubber-shaped elastic body (natural rubber, silicone rubber, EPDM, VMQ, etc.) that is integrally installed on the reinforcing member (310). The external dimensions of the gasket (300) related to the present embodiment in the planar shape are set to be identical to the external dimensions of the separator (200A) (the same applies to the separator (200B)) in the planar shape. Accordingly, since the gasket (300) can be placed so as to overlap between adjacent separators (200A) (separator (200B)), the assembly work is easy.

[0051] In addition, the reinforcing member (310) is composed of a film made of resin (PET, PE, PP, PPS, PEN, etc.), a resin member with high rigidity, a metal member (SUS, AL, etc.), etc. In this reinforcing member (310), a plurality of openings (311) are installed to serve as passages for the fluid to be sealed. Furthermore, when the separator (200A) (separator (200B)) and the gasket (300) are overlapped, the plurality of openings (311) are each installed to surround the outer side of the area enclosed by the sealing line (SL) above. In other words, the sealing line (SL) is formed on the inner side of the inner circumference (311a) of the opening (311) and also along the inner circumference (311a) of the opening (311).

[0052] The gasket body (320) is installed to cover the entire inner surface of each of the multiple openings (311) installed in the reinforcing member (310). The gasket body (320) has a thin portion (321) and a thick portion (322) integrally. The thin portion (321) is installed to cover a portion of one side of the surface of the reinforcing member (310) along the inner circumference (311b) of the opening (311). Additionally, the thick portion (322) is installed to protrude toward both sides within the opening.

[0053] In addition, in this embodiment, the Young's modulus of the reinforcing member (310) is configured to be higher than the Young's modulus of the gasket body (320). Furthermore, when a resin film is used as the reinforcing member (310), the Young's modulus is 0.2 GPa to 0.5 GPa when the resin material is PE, 1.0 GPa to 2.0 GPa when the resin material is PP, and 2 GPa to 4 GPa when the resin material is PET. In contrast, the Young's modulus of the gasket body (320) is 0.01 GPa to 0.1 GPa when the rubber material is natural rubber, and 0.01 GPa to 0.1 GPa when the rubber material is silicone rubber.

[0054] In addition, in this embodiment, the dimensions of each part are set to satisfy the following relationship. That is, if the thickness of the reinforcing member (310) is TF, the thickness of the thin-walled part (321) is TB, and the maximum thickness of the thick-walled part (322) is TG, it is set to satisfy 1 < TG / (TF + TB) ≤ 60. For example, the maximum value of TG can be set to 1.5 mm and the minimum value of (TF + TB) can be set to 0.025 mm.

[0055] Furthermore, in the case where a gasket (300) is fitted into a single cell, the maximum thickness T2 of the compressed gasket body (320) is configured to be larger than T1 (= TF + TB).

[0056] In a state where the gasket (300) configured as described above is fitted into a single cell, the gasket (300) is positioned in at least one of the gap between the separator and the electrolyte membrane and the gap between the separators. Accordingly, both sides of the thick portion (322) in the gasket body (320) come into contact with the separator (200A) and the electrolyte membrane (110) (see FIG. 5(b)) or with each of the pair of separators (200A) (see FIG. 5(c)). Accordingly, leakage of the fluid flowing through the manifold and the fluid flowing through the recess (210) can be suppressed. In addition, FIG. 5(b) and (c) show the configuration of a fuel cell, but the same applies to a water electrolysis device.

[0058] <Advantages of the gasket, fuel cell, and water electrolysis device related to the present embodiment>

[0059] According to the present embodiment, even if the pressure P (see FIG. 5(b, c)) of the fluid to be sealed on the thick portion (322) of the gasket body (320) increases, the gasket body (320) can be prevented from widening by the reinforcing member (310). That is, since the reinforcing member (310) hardly deforms, the deformation of the gasket body (320) (thick portion (322)) can be prevented by supporting the thick portion (322) by the inner circumferential surface (311a) of the reinforcing member (310). Accordingly, deformation such as the thick portion (322) becoming thin can be prevented, and the deterioration of sealing performance can be prevented. Furthermore, in the present embodiment, by setting the relationship of Young's modulus and the relationship of TF, TB, and TG to satisfy the above relationship, the deformation of the gasket body (320) due to the increase in the pressure of the fluid to be sealed can be effectively prevented. In addition, if TG / (TF + TB) is set to 1 or less, the thick section (322) is not compressed, and there is a risk of leakage. More preferably, it is desirable to satisfy 3 < TG / (TF + TB). Accordingly, since the thick section (322) can be sufficiently compressed while securing the rigidity of the reinforcing member (310), the sealing performance can be further enhanced. Also, if TG / (TF + TB) is greater than 60, the deformation suppression effect of the thick section (322) becomes insufficient, and there is a risk that the ejection suppression effect will not be sufficiently exerted. From the above, the leakage suppression effect of the fluid to be sealed can be enhanced even in an environment where the pressure of the fluid to be sealed is high. Explanation of the symbols

[0061] 10A: Fuel cell 10B: Water electrolysis device 100A:MEA 100B: Membrane unit 110: Electrolyte membrane 120, 130: Gas diffusion layer 140, 150: Entire house 200, 200A, 200B: Separator 210: Concave part 221: 1st manifold 222: Second manifold 223: Third manifold 300: Gasket 310: Reinforcing member 311: Opening 311a: If you give it to me 311b: My Main Character 320: Gasket body 321: Park Yuk-bu 322: Posterior meat

Claims

Claim 1 A gasket comprising a thin plate-shaped reinforcing member having an opening that serves as a passage for a fluid to be sealed, and a rubber-shaped elastic gasket body integrally installed on the reinforcing member to cover the entire inner surface of the opening, wherein the gasket body integrally comprises a thin-walled portion installed to cover a part of the surface of one side of the reinforcing member along the inner circumference of the opening, and a thick-walled portion installed to protrude toward both sides within the opening, wherein the Young's modulus of the reinforcing member is higher than the Young's modulus of the gasket body, and if the thickness of the reinforcing member is TF, the thickness of the thin-walled portion is TB, and the maximum thickness of the thick-walled portion is TG, the condition 3 < TG / (TF + TB) ≤ 60 is satisfied. Claim 2 A fuel cell comprising a plurality of single cells each having a membrane unit including an electrolyte membrane and a pair of separators disposed on both sides of the membrane unit, and characterized by having a gasket as described in claim 1 disposed in at least one of the gap between the separators and the gap between the separators and the membrane unit. Claim 3 A water electrolysis device comprising a membrane unit including an electrolyte membrane and a plurality of single cells each having a pair of separators disposed on both sides of the membrane unit, and characterized by having a gasket as described in claim 1 disposed in at least one of the gap between the separators and the gap between the separators and the membrane unit.

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