Sealing structure, fuel cell and fuel cell stack

Abstract

The utility model relates to the technical field of fuel cells, and provides a sealing structure, a fuel cell and a fuel cell stack. A part of the frame assembly is inserted between the catalyst layer and the gas diffusion layer of the membrane electrode; the sealing element forms sealing between the frame assembly and the bipolar plate, one side, facing the gas diffusion layer, of the sealing element is provided with a guide surface sunken towards the inner side of the sealing element, and fluid from the direction of the membrane electrode can steer to the bipolar plate or the frame assembly along the guide surface; and the sealing piece is an elastic piece. Therefore, the guide surface can reduce the acting force of fluid on the sealing element, the sealing element can generate elastic deformation, when the sealing element is subjected to the acting force of the fluid, the sealing element tends to extend towards the side where the bipolar plate and the frame assembly are located, the abutting force on the bipolar plate and the frame assembly is increased, and then the sealing effect is enhanced. And the frame assembly and the membrane electrode are fixed, so that the installation is easy.

Description

Technical Field

[0001] The utility model relates to the technical field of fuel cells, in particular to a sealing structure, a fuel cell and a fuel cell stack. Background Art

[0002] A proton exchange membrane fuel cell (PEMFC) monomer mainly consists of a membrane electrode, a seal and a bipolar plate with a gas conduction channel. The proton exchange membrane fuel cell converts the chemical energy released during the electrochemical reaction of hydrogen and oxygen into electrical energy, and has the advantages of high efficiency, environmental friendliness, mild working conditions, etc., and has always attracted much attention.

[0003] Sealing is a crucial link in fuel cells, which can prevent fuel leakage and prevent gas cross-contamination. A common sealing structure of fuel cells is that the seal and the membrane electrode are both clamped between the bipolar plates, and the seals are distributed on the periphery of the membrane electrode. Since the gas and / or liquid leaking from the membrane electrode side form a fluid and impact the seal, the seal always has a tendency to move away from the membrane electrode side, and the displacement tendency becomes more obvious over time, which easily causes gaps to appear on the contact surface between the seal and the bipolar plate and / or the frame during the relative movement, resulting in seal failure.

[0004] Therefore, there is an urgent need for a sealing structure, a fuel cell and a fuel cell stack to solve the above technical problems. Summary of the Utility Model

[0005] The purpose of the utility model is to provide a sealing structure, a fuel cell and a fuel cell stack, which can improve the stability and sealing performance of the seal between the bipolar plate and the frame.

[0006] To achieve the above object, the utility model adopts the following technical solutions:

[0007] A sealing structure is applicable to a fuel cell. The fuel cell includes a membrane electrode and a bipolar plate, and the membrane electrode is clamped between two bipolar plates. The sealing structure includes:

[0008] A frame assembly, a part of the frame assembly is inserted between the catalyst layer and the gas diffusion layer of the membrane electrode;

[0009] A seal, the seal forms a seal between the frame assembly and the bipolar plate. A guiding surface recessed inward of the seal is arranged on the side of the seal facing the gas diffusion layer, and the fluid from the direction of the membrane electrode can be redirected to the bipolar plate or the frame assembly along the guiding surface; the seal is an elastic member.

[0010] As a preferred technical solution of the above sealing structure, a supporting surface protruding outward of the seal is arranged on the side of the seal facing away from the gas diffusion layer.

[0011] As a preferred technical solution of the above sealing structure, the contact surfaces between the seal and the bipolar plate and between the seal and the frame assembly are parallel planes.

[0012] As a preferred technical solution of the above sealing structure, the contact area between the seal and the bipolar plate is S1, satisfying S1 < S2, where S2 is the contact area between the seal and the frame assembly.

[0013] As a preferred technical solution of the above sealing structure, the frame assembly includes a first frame and a second frame. The first frame is inserted between the catalyst layer and the gas diffusion layer. The second frame is located on one side of the membrane electrode in the first direction and is fixed to the first frame. The seal is clamped between the second frame and the bipolar plate;

[0014] The above first direction is the thickness direction of the membrane electrode.

[0015] As a preferred technical solution of the above sealing structure, a groove is formed on one side of the bipolar plate facing the frame assembly, and at least part of the seal is inserted into the groove.

[0016] As a preferred technical solution of the above sealing structure, the seal is disposed in the middle of the groove.

[0017] There is also provided a fuel cell, including the above-mentioned membrane electrode, the above-mentioned bipolar plate, and the above-mentioned sealing structure. The membrane electrode is clamped between two above-mentioned bipolar plates. The membrane electrode includes a proton exchange membrane, two above-mentioned catalyst layers, and two above-mentioned gas diffusion layers. The proton exchange membrane is clamped between two above-mentioned catalyst layers, and two above-mentioned catalyst layers are clamped between two above-mentioned gas diffusion layers. Part of the frame assembly is inserted between the catalyst layer and the gas diffusion layer.

[0018] As a preferred technical solution of the above fuel cell, the bipolar plate is divided into a first bipolar plate and a second bipolar plate located on opposite sides of the proton exchange membrane. The first bipolar plate, the second bipolar plate, and the membrane electrode are correspondingly provided with limiting grooves in the first direction;

[0019] The above first direction is the thickness direction of the membrane electrode.

[0020] There is also provided a fuel cell stack, including a plurality of the above-mentioned fuel cells. The plurality of fuel cells are stacked in the above first direction, and the first bipolar plate of the fuel cell is in close contact with the second bipolar plate of the adjacent fuel cell.

[0021] Advantages of the present utility model:

[0022] A sealing structure is provided, which is applicable to a fuel cell. The fuel cell includes a membrane electrode and bipolar plates, and the membrane electrode is clamped between two bipolar plates. The sealing structure includes a frame assembly and a seal. Among them, a part of the frame assembly is inserted between the catalyst layer and the gas diffusion layer of the membrane electrode; the seal forms a seal between the frame assembly and the bipolar plate, and a guiding surface recessed inwardly towards the seal is provided on one side of the seal facing the gas diffusion layer, and the fluid from the direction of the membrane electrode can be redirected to the bipolar plate or the frame assembly along the guiding surface; the seal is an elastic member.

[0023] Specifically, the seal includes an upper end surface, a lower end surface and an inner side surface. The upper end surface abuts against the bipolar plate, and the lower end surface abuts against the frame assembly. In this way, the seal formed between the bipolar plate and the frame assembly can limit the overflow of the fluid inside the membrane electrode. The inner side surface is located on the side of the seal facing the gas diffusion layer, and the inner side surface plays a guiding role, guiding the fluid blown from the membrane electrode to the seal to the bipolar plate or the frame assembly. Since both the bipolar plate and the frame assembly are relatively fixed to the membrane electrode, deformation or relative displacement generally does not occur, thereby reducing the force of the fluid acting on the seal; further, the seal can undergo elastic deformation in combination with the recessed guiding surface of the inner side surface. When the seal is subjected to the force of the fluid, the seal has a tendency to extend towards the side where the bipolar plate and the frame assembly are located, increasing the abutting force on both of them, thereby strengthening the sealing effect. And the fixing method of the frame assembly and the membrane electrode is easy to install. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for description in the embodiments of the present invention. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained according to the content of the embodiments of the present invention and these drawings.

[0025] Figure 1 is a schematic structural diagram of the sealing structure provided by the embodiment of the present invention;

[0026] Figure 2 is a schematic structural diagram of the sealing structure provided by other embodiments of the present invention;

[0027] Figure 3 is a schematic structural diagram of the fuel cell provided by the embodiment of the present invention;

[0028] Figure 4 is an exploded view of the fuel cell stack provided by the embodiment of the present invention.

[0029] In the figure:

[0030] X, the first direction; Y, the second direction;

[0031] 10, membrane electrode; 11, catalyst layer; 12, gas diffusion layer; 13, proton exchange membrane;

[0032] 20, bipolar plate; 20a, first bipolar plate; 20b, second bipolar plate; 21, groove;

[0033] 30, frame assembly; 31, first frame; 32, second frame;

[0034] 40, seal; 41, guiding surface; 42, supporting surface;

[0035] 50, limiting groove. Detailed implementation mode

[0036] The present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the present utility model, rather than limiting the present utility model. In addition, it should be noted that for the convenience of description, only the parts related to the present utility model are shown in the drawings, rather than all the structures.

[0037] In the description of the present utility model, unless otherwise clearly defined and limited, the terms "connected", "connected" and "fixed" shall be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection or an electrical connection; it may be directly connected, or indirectly connected through an intermediate medium, and it may be the communication inside two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific situations.

[0038] In the present utility model, unless otherwise clearly defined and limited, the first feature being "above" or "below" the second feature may include the direct contact between the first and second features, or may include the situation where the first and second features are not in direct contact but in contact through other features therebetween. Moreover, the first feature being "above", "above" and "on" the second feature includes that the first feature is directly above and obliquely above the second feature, or only means that the horizontal height of the first feature is higher than that of the second feature. The first feature being "below", "below" and "under" the second feature includes that the first feature is directly below and obliquely below the second feature, or only means that the horizontal height of the first feature is lower than that of the second feature.

[0039] In the description of this embodiment, the orientation or positional relationships such as "upper", "lower", "right", etc. are based on the orientation or positional relationship shown in the drawings. They are only for the convenience of description and simplifying the operation, rather than indicating or implying that the device or component referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present utility model. In addition, the terms "first" and "second" are only used for distinction in description and have no special meaning.

[0040] As Figures 1 to 3 shown, the present utility model provides a sealing structure applicable to a fuel cell. The fuel cell includes a membrane electrode 10 and bipolar plates 20. The membrane electrode 10 is clamped between two bipolar plates 20. The sealing structure includes a frame assembly 30 and a seal 40. Among them, a part of the frame assembly 30 is inserted between the catalyst layer 11 and the gas diffusion layer 12 of the membrane electrode 10; the seal 40 forms a seal between the frame assembly 30 and the bipolar plate 20. A guiding surface 41 that is recessed inwardly toward the seal 40 is provided on one side of the seal 40 facing the gas diffusion layer 12. The fluid from the direction of the membrane electrode 10 can be redirected along the guiding surface 41 to the bipolar plate 20 or the frame assembly 30; the seal 40 is an elastic member.

[0041] In this embodiment, the fluid direction is the second direction Y. When the seal 40 is subjected to the force in the second direction Y, it can elastically deform in the first direction X. The first direction X is perpendicular to the second direction Y, and the first direction is the thickness direction of the membrane electrode 10.

[0042] Specifically, the seal 40 includes an upper end surface, a lower end surface and an inner side surface. The upper end surface abuts against the bipolar plate 20, and the lower end surface abuts against the frame assembly 30. In this way, the seal formed between the bipolar plate 20 and the frame assembly 30 can limit the fluid in the membrane electrode 10 from overflowing. The inner side surface is located on the side of the seal 40 facing the gas diffusion layer 12, and the inner side surface plays a guiding role, guiding the fluid that escapes from the membrane electrode 10 to the seal 40 to the bipolar plate 20 or the frame assembly 30. Since both the bipolar plate 20 and the frame assembly 30 are relatively fixed to the membrane electrode 10, they generally do not deform or displace relatively, thereby reducing the force of the fluid acting on the seal 40; further, the seal 40 can elastically deform in combination with the inwardly recessed guiding surface 41 of the inner side surface. When the seal 40 is subjected to the force of the fluid, the seal 40 has a tendency to extend toward the side where the bipolar plate 20 and the frame assembly 30 are located, increasing the abutting force on both of them, thereby strengthening the sealing effect. And the fixing method of the frame assembly 30 and the membrane electrode 10 is easy to install.

[0043] Preferably, the guiding surface 41 is arc-shaped, and the corresponding central angle ranges from 20° to 180°.

[0044] Specifically, the material of the seal 40 is selected from any one of polyimide, rubber, polyurethane, and epoxy resin.

[0045] Specifically, the seal 40 is fixed to the frame assembly 30 by one or several processes such as bonding, dispensing, and injection molding. Bonding, dispensing, and injection molding are all reliable sealing and forming processes, which can meet the sealing requirements of the fuel cell.

[0046] Optionally, a support surface 42 protruding outward from the seal 40 is provided on the side of the seal 40 facing away from the gas diffusion layer 12. The provision of the support surface 42 limits the range of extension of the seal 40 towards the bipolar plate 20 and the frame assembly 30, and avoids damage to the bipolar plate 20 and / or the frame assembly 30 caused by excessive extension of the seal 40.

[0047] Optionally, the contact surface between the seal 40 and the bipolar plate 20 and the contact surface between the seal 40 and the frame assembly 30 are parallel planes. In this way, when the seal 40 applies force evenly to the bipolar plate 20 and the frame assembly 30, slippage and misalignment can be avoided, and the contact area is increased, improving the sealing performance.

[0048] Preferably, the connection between the guiding surface 41 and the plane is in an arc transition, with a radius range of 0.01 mm to 0.2 mm and an angle range between 45° and 180°.

[0049] Preferably, the connection between the support surface 42 and the plane is in an arc transition, with a radius range of 0.01 to 0.2 mm and an angle range between 45° and 180°.

[0050] Optionally, the contact area between the seal 40 and the bipolar plate 20 is S1, satisfying S1 < S2, where S2 is the contact area between the seal 40 and the frame assembly 30. In this way, when the seal 40 undergoes elastic deformation under the action of fluid force, it tends to extend towards the bipolar plate 20 side, reducing the force on the frame assembly 30.

[0051] Preferably, in the second direction Y, the length dimension of the contact surface between the seal 40 and the bipolar plate 20 ranges from 0.2 mm to 2 mm, and the length dimension of the contact surface between the seal 40 and the frame assembly 30 ranges from 1 mm to 4 mm.

[0052] Preferably, in the first direction X, the thickness dimension of the seal 40 ranges from 0.2 mm to 0.6 mm.

[0053] Optionally, in the projection in the first direction X, at least a part of the contact surface between the seal 40 and the bipolar plate 20 coincides with the contact surface between the seal 40 and the frame assembly 30. With such an arrangement, when the seal 40 is squeezed by the bipolar plate 20 and the frame assembly 30, it can prevent the seal 40 from tilting, resulting in the sealing failure between the seal 40 and the bipolar plate 20 and / or the frame assembly 30.

[0054] Preferably, in the first direction X, the projection of the contact surface between the seal 40 and the bipolar plate 20 is entirely within the projection of the contact surface between the seal 40 and the frame assembly 30.

[0055] As Figure 2 shown, in this embodiment, the frame assembly 30 includes a first frame 31, and a part of the first frame 31 is inserted between the catalyst layer 11 and the gas diffusion layer 12, and the seal 40 is fixed to the first frame 31.

[0056] Furthermore, as Figure 3 shown, in other embodiments, the frame assembly 30 further includes a second frame 32, the second frame 32 is located on one side of the membrane electrode 10 in the first direction X and is fixed to the first frame 31, and the seal 40 is clamped between the second frame 32 and the bipolar plate 20. The first direction X is the thickness direction of the membrane electrode 10. Thus, by adding the second frame 32, the thickness of the first frame 31 can be increased, thereby improving its structural strength.

[0057] Optionally, a groove 21 is formed on one side of the bipolar plate 20 facing the frame assembly 30, and at least a part of the seal 40 is inserted into the groove 21. By providing the groove 21 on the bipolar plate 20, it is used to install the seal 40.

[0058] Optionally, the seal 40 is centered in the groove 21.

[0059] As Figure 1 shown, a fuel cell is further provided, which includes the above-mentioned membrane electrode 10, bipolar plate 20 and sealing structure. The membrane electrode 10 is clamped between two bipolar plates 20. The membrane electrode 10 includes a proton exchange membrane 13, two catalyst layers 11 and two gas diffusion layers 12. The proton exchange membrane 13 is clamped between the two catalyst layers 11, and the two catalyst layers 11 are clamped between the two gas diffusion layers 12. A part of the frame assembly 30 is inserted between the catalyst layer 11 and the gas diffusion layer 12.

[0060] Optionally, the bipolar plate 20 is divided into a first bipolar plate 20a and a second bipolar plate 20b located on opposite sides of the proton exchange membrane 13. The first bipolar plate 20a, the second bipolar plate 20b, and the membrane electrode 10 are correspondingly provided with limiting grooves 50 along the first direction X, where the first direction X is the thickness direction of the membrane electrode 10. In this way, the first bipolar plate 20a, the membrane electrode 10, and the second bipolar plate 20b can be aligned through the limiting grooves 50, improving the assembly consistency and simplifying the alignment operation of the assembly, thereby enhancing the sealing performance.

[0061] As Figure 4 shown, a fuel cell stack is also provided, which includes a plurality of the above fuel cells stacked along the first direction X, and the first bipolar plate 20a of a fuel cell is in close contact with the second bipolar plate 20b of the adjacent fuel cell.

[0062] In addition, the above is only the preferred embodiment of the present invention and the applied technical principle. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described here, and various obvious changes, re-adjustments, and substitutions can be made by those skilled in the art without departing from the protection scope of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments only. Without departing from the concept of the present invention, more other equivalent embodiments can be included, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A sealing structure, suitable for a fuel cell, wherein the fuel cell comprises a membrane electrode (10) and a bipolar plate (20), wherein the membrane electrode (10) is clamped between two bipolar plates (20), and wherein: The sealing structure comprises: A frame assembly (30), wherein a portion of the frame assembly (30) is inserted between the catalyst layer (11) and the gas diffusion layer (12) of the membrane electrode (10); A sealing member (40), wherein the sealing member (40) forms a seal between the frame assembly (30) and the bipolar plate (20), and a guide surface (41) recessed toward the inner side of the sealing member (40) is provided on the side of the sealing member (40) facing the gas diffusion layer (12), so that the fluid from the membrane electrode (10) can be diverted along the guide surface (41) to the bipolar plate (20) or the frame assembly (30); the sealing member (40) is an elastic member.

2. The sealing structure according to claim 1, characterized in that: A support surface (42) protruding toward the outside of the sealing member (40) is provided on the side of the sealing member (40) facing away from the gas diffusion layer (12).

3. The sealing structure according to claim 1, characterized in that: The contact surface between the sealing member (40) and the bipolar plate (20) and the contact surface between the sealing member (40) and the frame assembly (30) are parallel planes.

4. The sealing structure according to claim 1, characterized in that: The contact area between the sealing member (40) and the bipolar plate (20) is S1, satisfying the condition S1<S2, and S2 is the contact area between the sealing member (40) and the frame assembly (30).

5. The sealing structure according to claim 1, characterized in that: The frame assembly (30) comprises a first frame (31) and a second frame (32), the first frame (31) being inserted between the catalyst layer (11) and the gas diffusion layer (12), the second frame (32) being located on one side of the membrane electrode (10) in a first direction (X) and being fixed to the first frame (31), and the sealing member (40) being sandwiched between the second frame (32) and the bipolar plate (20); The first direction (X) is the thickness direction of the membrane electrode (10).

6. The sealing structure according to claim 1, characterized in that: A groove (21) is provided on one side of the bipolar plate (20) facing the frame assembly (30), and the sealing member (40) is at least partially inserted into the groove (21).

7. The sealing structure according to claim 6, characterized in that: The sealing member (40) is centrally arranged in the groove (21).

8. A fuel cell, characterized in that The invention comprises the sealing structure according to any one of claims 1 to 7, the membrane electrode (10) and the bipolar plate (20), wherein the membrane electrode (10) is sandwiched between two bipolar plates (20), the membrane electrode (10) comprises a proton exchange membrane (13), two catalyst layers (11) and two gas diffusion layers (12), the proton exchange membrane (13) is sandwiched between the two catalyst layers (11), the two catalyst layers (11) are sandwiched between the two gas diffusion layers (12), and part of the frame assembly (30) is inserted between the catalyst layer (11) and the gas diffusion layer (12).

9. The fuel cell according to claim 8, characterized in that The bipolar plate (20) is divided into a first bipolar plate (20a) and a second bipolar plate (20b) located on opposite sides of the proton exchange membrane (13), and the first bipolar plate (20a), the second bipolar plate (20b) and the membrane electrode (10) are provided with corresponding limiting grooves (50) along a first direction (X); The first direction (X) is the thickness direction of the membrane electrode (10).

10. A fuel cell stack, characterized in that: Comprising a plurality of fuel cells as claimed in claim 9, wherein the plurality of fuel cells are stacked along the first direction (X), and the first bipolar plate (20a) of the fuel cell is in close contact with the second bipolar plate (20b) of the adjacent fuel cell.

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