A bipolar plate for an electrolytic cell

Abstract

This invention provides a bipolar plate for an electrolyzer. The anode surface of the bipolar plate is provided with a first sealing element and a first cover plate. The first sealing element is located around the anode surface, the outer periphery of the hydrogen outlet, and the outer periphery of the inlet / outlet. The first cover plate is located between the inlet / outlet and the first distribution area on the anode surface of the bipolar plate, and its lower surface has a first flow channel. The cathode surface of the bipolar plate is provided with a second sealing element and a second cover plate. The second sealing element is located around the cathode surface, the outer periphery of the hydrogen outlet, and the outer periphery of the inlet / outlet. The second cover plate is located between the hydrogen outlet and the second distribution area, and its lower surface has a second flow channel. Elastic supports are provided on the upper surfaces of the first and second cover plates. The lower surfaces of the first and second cover plates are sequentially stacked with the bipolar plate and the second / first sealing element. This invention adds an elastic support to the upper surface of the cover plate, which can improve the internal leakage of the PEM electrolyzer.

Description

Technical Field

[0001] This utility model belongs to the field of PEM hydrogen production technology, specifically relating to a bipolar plate for an electrolyzer. Background Technology

[0002] Proton exchange membrane (PEM) water electrolysis for hydrogen production has become a key area for future development due to its compact structure, high efficiency, strong adaptability, high hydrogen purity, wide operating range, and environmental friendliness.

[0003] The PEM electrolyzer is a highly efficient hydrogen production device, mainly composed of several electrolysis chambers connected in series. Each electrolysis chamber is primarily composed of bipolar plates, cathode seals, cathode gas diffusion layers, membrane electrodes, anode gas diffusion layers, and anode seals stacked sequentially.

[0004] Bipolar plates are key components of electrolytic cells, primarily serving functions such as electrical connection, separation of adjacent electrolysis chambers, fluid distribution, mass transfer, thermal management, and mechanical support. A bipolar plate has an anode side and a cathode side, each typically having a corresponding flow field to regulate the two-phase flow distribution within the electrolytic cell. The anode side mainly handles the transport of reactant water and the reaction product oxygen, requiring the uniform distribution of reactant water and the rapid removal of the reaction product oxygen. The cathode side primarily handles permeated water and the reaction product hydrogen, requiring its rapid removal.

[0005] Existing bipolar plates have corresponding flow structures at the inlet / outlet water ports and the outlet hydrogen port, with a sealing structure on the back of the corresponding position of the flow structure. The flow structures typically fall into two categories:

[0006] 1. Concave-convex flow channel structure; 2. Cover plate structure with flow channel.

[0007] Because the components of the electrolytic cell will undergo certain micro-deformation when it is locked, and the rigid structure will experience a large stress difference at the back seal after micro-deformation, which will cause the seal to fail and increase the internal leakage of the PEM electrolytic cell. Summary of the Invention

[0008] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a bipolar plate for an electrolytic cell. This invention optimizes the cover plate structure with a flow channel by adding an elastic support to the upper surface of the cover plate. When the bipolar plate undergoes slight deformation, the elastic body's own compression characteristics reduce the stress difference in the corresponding sealing area, thereby improving internal leakage in the PEM electrolytic cell caused by the slight deformation of the bipolar plate.

[0009] To achieve the above technical objectives, the technical solution adopted in this utility model embodiment is as follows:

[0010] An electrolytic cell bipolar plate, wherein the bipolar plate is formed by stamping to form an anode surface on one side of the plate and a cathode surface on the other side; the anode surface of the bipolar plate is provided with a first sealing element and a first cover plate, the first sealing element being disposed around the anode surface of the bipolar plate, around the hydrogen outlet, and around the inlet / outlet of the water, for preventing reactants and reaction products from leaking to the outside of the anode surface of the bipolar plate and from entering the cathode surface of the bipolar plate through the hydrogen outlet to form internal leakage;

[0011] The first cover plate is disposed between the inlet / outlet of the bipolar plate anode surface and the first distribution area. The lower surface of the first cover plate is provided with a first flow channel to ensure that the reactant water flows smoothly into the bipolar plate from the inlet and flows smoothly out.

[0012] The cathode surface of the bipolar plate is provided with a second sealing element and a second cover plate. The second sealing element is located around the cathode surface of the bipolar plate, around the hydrogen outlet, and around the inlet / outlet of the water inlet, and is used to prevent the reaction products of the cathode surface of the bipolar plate from leaking to the outside and from entering the anode surface of the bipolar plate through the inlet / outlet of the water inlet to form internal leakage.

[0013] The second cover plate is disposed between the hydrogen outlet and the second distribution zone. The lower surface of the second cover plate is provided with a second flow channel to ensure that the reaction product hydrogen gas and the water that permeates into the cathode surface of the bipolar plate are smoothly discharged from the hydrogen outlet.

[0014] The upper surfaces of the first cover plate and the second cover plate are provided with elastic supports, and the lower surfaces of the first cover plate / second cover plate are sequentially stacked with bipolar plates and second sealing elements / first sealing elements.

[0015] Furthermore, the width of the elastic support body satisfies the following condition: the width of the first seal / second seal is less than the width of the elastic support body, which is less than the width of the first cover plate / second cover plate, and the relative distance between the width of the elastic support body and the width of the first cover plate / second cover plate after mating is ≥0.5mm on one side.

[0016] Furthermore, the height of the elastic support after compression is greater than or equal to the height of the first seal / second seal after compression, and the difference between the height of the elastic support and the height of the first seal / second seal after compression is less than or equal to 5% of the original height of the first seal / second seal.

[0017] Furthermore, the bipolar plate is stamped and formed, and a first active region is formed on the anode surface of the bipolar plate. A first distribution region is provided on both sides of the first active region, and a water inlet / outlet and a hydrogen outlet are provided on the outer side of the first distribution region.

[0018] The cathode surface of the bipolar plate has a second active region, and a second distribution region is provided on both sides of the second active region. A water inlet / outlet and a hydrogen outlet are provided on the outer side of the second distribution region.

[0019] Furthermore, the width of the first flow channel / second flow channel is a, and the depth is b, and they are distributed periodically on the first cover plate and the second cover plate, respectively.

[0020] Where 0.5mm≤a≤1.2mm, db≥0.15mm, d is the thickness of the first cover plate and the second cover plate, and c≥a+0.1mm.

[0021] The beneficial effects of the technical solution provided by this utility model embodiment are:

[0022] This invention optimizes the cover plate structure with a flow channel by adding an elastic support body to the upper surface of the cover plate. When the bipolar plate undergoes slight deformation, the elastic body's own compression characteristics reduce the difference in force on the corresponding sealing parts, thereby improving internal leakage.

[0023] This invention mainly optimizes the structure of the cover plates at the water inlet / outlet and hydrogen outlet. An elastic support is added to the surface of the cover plate to provide elastic compensation when the bipolar plate undergoes slight deformation under the locking force. This reduces the stress difference in the seal caused by the slight deformation of the bipolar plate, thereby improving internal leakage. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of the anode surface of the bipolar plate in an embodiment of this utility model.

[0025] Figure 2 This is a schematic diagram of the structure of the cathode surface of the bipolar plate in an embodiment of this utility model.

[0026] Figure 3 This is a schematic diagram of the structure of the first flow channel on the first cover plate in an embodiment of this utility model.

[0027] Figure 4 This is a schematic cross-sectional view of the first cover plate position in an embodiment of this utility model.

[0028] Figure 5 This is a schematic diagram of the failure of the existing structure.

[0029] Figure 6 This is a schematic diagram illustrating the principle of bipolar plates improving internal leakage in this embodiment of the present invention.

[0030] Figure 7 This is a structural schematic diagram of the relative distance between the edges on one side of an embodiment of the present invention.

[0031] Explanation of reference numerals in the attached diagram: 1-Anode side of bipolar plate; 2-Cathode side of bipolar plate; 3-Elastic support; 4-End plate; 5-Hydrogen outlet; 6-Water inlet; 7-Water outlet;

[0032] 11-First sealing element; 12-First cover plate; 13-First distribution area; 14-First flow channel; 15-First active area;

[0033] 21-Second seal; 22-Second cover plate; 23-Second distribution area; 24-Second flow channel; 25-Second active area. Detailed Implementation

[0034] In the description of this utility model, it should be understood that the directional terms such as "inner" and "outer", "upper" and "lower", "left" and "right" indicate the orientation or positional relationship, which are usually based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as limiting the scope of protection of this utility model.

[0035] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this utility model and are not intended to limit this utility model.

[0036] Example 1

[0037] like Figure 1 and 2 As shown, an electrolytic cell bipolar plate is formed by stamping to form a bipolar plate anode surface 1 on one side of the plate and a bipolar plate cathode surface 2 on the other side.

[0038] The anode surface 1 of the bipolar plate is provided with a first sealing element 11 and a first cover plate 12;

[0039] The first sealing element 11 is disposed around the anode surface 1 of the bipolar plate, around the hydrogen outlet 5, and around the inlet / outlet of the water inlet, and is used to prevent the reactants and reaction products of the anode from leaking to the outside and from entering the anode surface 1 of the bipolar plate through the hydrogen outlet 5 to form internal leakage.

[0040] The flow path of the reactant water is as follows: Inlet 6 → Cover plate flow channel → First distribution zone → Activated zone → Second distribution zone → Outlet 7.

[0041] like Figure 3 As shown, the first cover plate 12 is disposed between the inlet / outlet of the bipolar plate anode surface 1 and the first distribution area 14. The lower surface of the first cover plate 12 is provided with a first flow channel 14 to ensure that the reactant water flows smoothly into the bipolar plate from the inlet and flows smoothly out.

[0042] The cathode surface 2 of the bipolar plate is provided with a second sealing element 21 and a second cover plate 22. The second sealing element 21 is located around the cathode surface 2 of the bipolar plate, around the hydrogen outlet 5, and around the inlet / outlet water outlet. It is used to prevent the reaction products of the cathode surface 2 of the bipolar plate from leaking to the outside and from entering the anode surface 1 of the bipolar plate through the inlet / outlet water outlet to form internal leakage.

[0043] The hydrogen flow path is as follows: bipolar plate active area (hydrogen production area) → first / second distribution area → hydrogen outlet 5.

[0044] The second cover plate 22 is disposed between the hydrogen outlet 5 and the second distribution area 23. The lower surface of the second cover plate 22 is provided with a second flow channel 24 to ensure that the reaction product hydrogen gas and the water that permeates into the cathode surface 2 of the bipolar plate are smoothly discharged from the hydrogen outlet 5.

[0045] like Figure 4 As shown, the upper surface of the first cover plate 12 is provided with an elastic support 3, and the lower surface of the first cover plate 12 is provided with a bipolar plate and a second sealing member 21 stacked in sequence.

[0046] The upper surface of the second cover plate 22 is provided with an elastic support 3, and the lower surface of the second cover plate 22 is provided with a bipolar plate and a first sealing element 11 stacked in sequence.

[0047] The width of the elastic support 3 satisfies the following conditions: the width of the first seal 11 is less than the width of the elastic support 3 and the width of the first cover plate 12. After the elastic support 3 and the first cover plate 12 are fitted together, the relative distance between their single-sided edges is ≥0.5mm.

[0048] The width of the second seal 21 is less than the width of the elastic support 3, which is less than the width of the second cover plate 22. After the elastic support 3 and the second cover plate 22 are fitted together, the relative distance between their single-sided edges is ≥0.5mm. Here, the relative distance between their single-sided edges refers to the distance between the surface of one part and the surface of the other part after the centers of the two parts are overlapped. Figure 7 As shown, 'a' represents the relative distance between the two edges.

[0049] The height of the elastic support 3 after compression is greater than or equal to the height of the first seal 11 after compression, and the difference between the heights of the elastic support 3 and the first seal 11 after compression is less than or equal to 5% of the original height of the first seal 11.

[0050] The height of the elastic support 3 after compression is greater than or equal to the height of the second seal 21 after compression, and the difference between the heights of the elastic support 3 and the second seal 21 after compression is less than or equal to 5% of the original height of the second seal 21.

[0051] The bipolar plate is formed by stamping, and a first active region 15 is formed on the anode surface 1 of the bipolar plate. A first distribution region 13 is provided on both sides of the first active region 15. A water inlet / outlet and a hydrogen outlet 5 are provided on the outer side of the first distribution region 13.

[0052] A second active region 25 is formed on the cathode surface 2 of the bipolar plate. A second distribution region 23 is provided on both sides of the second active region 25. A water inlet / outlet and a hydrogen outlet 5 are provided on the outer side of the second distribution region 23.

[0053] The width of the first flow channel 14 and the depth of the second flow channel 24 are a and b, respectively, and they are distributed periodically c on the first cover plate 12 and the second cover plate 22, where 0.5mm≤a≤1.2mm, db≥0.15mm, d is the thickness of the first cover plate 12 and the second cover plate 22, and c≥a+0.1mm.

[0054] The elastic support 3 and the first seal 11, and the elastic support 3 and the second seal 21 adopt an integral structure or a separate structure.

[0055] like Figure 5 As shown, under the stacking locking force, the pressure from the end plate 4 causes slight deformation of the bipolar plate anode surface 1 and the bipolar plate cathode surface 2. The bipolar plate anode surface 1 and the bipolar plate cathode surface 2, along with the first cover plate 12 and the second cover plate 22, are all rigid structures. When slight deformation occurs in the bipolar plate anode surface 1 and the bipolar plate cathode surface 2, the contact state between them and the first cover plate 12 and the second cover plate 22 changes, resulting in small gaps that affect the force transmission at these points. This causes uneven stress on the first seal 11 and the second seal 21 at these points. When this stress exceeds the self-compensation range of the first seal 11 and the second seal 21, internal leakage occurs. Figure 6 As shown, by adding an elastic support 3 to the upper surface of the first cover plate 12 and the second cover plate 22, the compression characteristics of the elastic support 3 itself are used to fill the small gaps caused by the deformation of the bipolar plate, thereby improving the uneven stress state of the first seal 11 and the second seal 21 and improving internal leakage.

[0056] Finally, it should be noted that the above specific embodiments are only used to illustrate the technical solution of this utility model and not to limit it. Although this utility model has been described in detail with reference to examples, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solution of this utility model without departing from the spirit and scope of the technical solution of this utility model, and all such modifications and substitutions should be covered within the scope of the claims of this utility model.

Claims

1. A bipolar plate for an electrolytic cell, characterized in that, The bipolar plate is formed by stamping to form a bipolar plate anode surface (1) on one side of the plate and a bipolar plate cathode surface (2) on the other side; the bipolar plate anode surface (1) is provided with a first sealing element (11) and a first cover plate (12). The first sealing element (11) is provided on the periphery of the bipolar plate anode surface (1), the periphery of the hydrogen outlet (5) and the periphery of the water inlet / outlet, to prevent the reactants and reaction products of the bipolar plate anode surface (1) from leaking to the outside and from entering the bipolar plate cathode surface (2) through the hydrogen outlet to form internal leakage; The first cover plate (12) is disposed between the inlet / outlet of the bipolar plate anode surface (1) and the first distribution area (13). The lower surface of the first cover plate (12) is provided with a first flow channel (14) to ensure that the reactant water flows smoothly into the bipolar plate from the inlet and is smoothly discharged. The cathode surface (2) of the bipolar plate is provided with a second sealing element (21) and a second cover plate (22). The second sealing element (21) is provided on the periphery of the cathode surface (2), the outer periphery of the hydrogen outlet (5) and the outer periphery of the water inlet / outlet, in order to prevent the reaction products of the cathode surface (2) of the bipolar plate from leaking to the outside and from entering the anode surface (1) of the bipolar plate through the water inlet / outlet to form internal leakage. The second cover plate (22) is disposed between the hydrogen outlet (5) and the second distribution area (23). The lower surface of the second cover plate (22) is provided with a second flow channel (24) to ensure that the reaction product hydrogen gas and the water that permeates into the cathode surface (2) of the bipolar plate are smoothly discharged from the hydrogen outlet (5). The upper surfaces of the first cover plate (12) and the second cover plate (22) are provided with elastic support (3), and the lower surfaces of the first cover plate (12) and the second cover plate (22) are sequentially stacked with bipolar plates and second sealing element (21) and first sealing element (11).

2. The bipolar plate of the electrolytic cell according to claim 1, characterized in that, The width of the elastic support (3) satisfies the following conditions: the width of the first seal (11) / second seal (21) is less than the width of the elastic support (3) and the width of the first cover plate (12) / second cover plate (22). After mating, the relative distance between the width of the elastic support (3) and the width of the first cover plate (12) / second cover plate (22) on one side is ≥0.5mm.

3. The bipolar plate of the electrolytic cell according to claim 1, characterized in that, The height of the elastic support (3) after compression is greater than or equal to the height of the first seal (11) / the second seal (21) after compression, and the difference between the height of the elastic support (3) and the height of the first seal (11) / the second seal (21) after compression is less than or equal to 5% of the original height of the first seal (11) / the second seal (21).

4. The bipolar plate of the electrolytic cell according to claim 1, characterized in that, The bipolar plate is formed by stamping, and the anode surface (1) of the bipolar plate forms a first active area (15). A first distribution area (13) is provided on both sides of the first active area (15). A water inlet / outlet and a hydrogen outlet (5) are provided on the outer side of the first distribution area (13). The cathode surface (2) of the bipolar plate has a second active region (25), and a second distribution region (23) is provided on both sides of the second active region (25). A water inlet / outlet and a hydrogen outlet (5) are provided on the outer side of the second distribution region (23).

5. The bipolar plate of the electrolytic cell according to claim 1, characterized in that, The width of the first flow channel (14) and the depth of the second flow channel (24) are a and b, respectively, and they are distributed periodically c on the first cover plate (12) and the second cover plate (22); Where 0.5mm≤a≤1.2mm, db≥0.15mm, where d is the thickness of the first cover plate (12) and the second cover plate (22), and c≥a+0.1mm.

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