Bipolar plate, electrolysis chamber and electrolytic cell

Abstract

This application discloses a bipolar plate, electrolysis chamber, and electrolyzer, relating to the field of water electrolysis hydrogen production technology. The bipolar plate comprises a plate body; a portion of the plate body arches away from one side thereof to form a raised structure; the raised structures are multiple and evenly spaced; and a buffer zone with a zigzag profile is formed between the raised structures near the water outlet or water inlet of the plate body. This design eliminates the need for multiple layers of sintered titanium mesh, effectively reducing process assembly difficulty and cost. It also reduces water / air inlet resistance and water / air outlet resistance, while ensuring effective contact area on the plate body, lowering layer resistance and operating voltage, and improving hydrogen production efficiency.

Description

Technical Field

[0001] The present application relates to the technical field of hydrogen production by water electrolysis, and in particular to a bipolar plate, an electrolysis chamber, and an electrolytic cell. Background Art

[0002] Bipolar plates are the core components of PEM water electrolysis hydrogen production equipment. The PEM electrolyzer has a "one plate, two fields" structure, which separates the water and oxygen mixture at the anode and the hydrogen at the cathode on both sides. The main functions of the bipolar plate are to support the diffusion layer, conduct gas and cool ionized water (which also serves as a reactant), and transmit electrolysis current. Most existing bipolar plates are flat plate structures, such as a bipolar plate assembly and electrolyzer disclosed in Chinese patent publication number CN115287699A. However, because this flat plate structure does not have the function of flow channel diversion, a multi-layer sintered titanium mesh needs to be added to the anode side of the bipolar plate in the electrolyzer to promote uniform diffusion of water flow, while increasing the difficulty and cost of process assembly. Summary of the Invention

[0003] In view of this, the purpose of the present application is to provide a bipolar plate, an electrolysis chamber and an electrolysis cell to solve the technical problems of high process assembly difficulty and high cost of the existing flat-plate structure bipolar plates.

[0004] To achieve the above technical objectives, the present application provides a bipolar plate, comprising a plate body;

[0005] The portion of the electrode body arches in a direction away from one side thereof to form a convex structure;

[0006] There are multiple protrusion structures that are evenly distributed;

[0007] A buffer zone with a zigzag outline is formed between the protruding structures near the water outlet or the water inlet on the electrode body.

[0008] Furthermore, the protruding structure is in a frustum shape, and a plane is provided on the top of the protruding structure.

[0009] Furthermore, the thickness of the electrode plate body is t, and the height of the protrusion is H, wherein 3t≤H≤4t.

[0010] Furthermore, the diameter of the top plane of the protrusion structure is D, wherein 4H≤D≤4.5H;

[0011] The total top plane area of all the protruding structures is S 总 The area of one side of the plate body when there is no protrusion is S 初 , of which 0.4S 初 ≤S 总 ≤0.5S 初 .

[0012] Furthermore, the plurality of protruding structures are in a rectangular array;

[0013] The array spacing between adjacent protrusion structures in the first array direction is B1, wherein 6H≤B1≤6.5H;

[0014] The array spacing between adjacent protrusion structures in the second array direction is B2, wherein 5.5H≤B2≤6H.

[0015] Furthermore, the slope of the protruding structure is θ, wherein 45°≤θ≤60°.

[0016] Furthermore, the plurality of protruding structures are in a rectangular array;

[0017] The protruding structures in two adjacent rows are staggered so that a buffer zone with a zigzag profile is formed between the protruding structures near the water outlet or water inlet on the electrode body.

[0018] The present application also discloses an electrolysis chamber, comprising a frame assembly and two bipolar plates;

[0019] The two bipolar plates are fixedly mounted on both sides of the frame assembly;

[0020] The top of the raised structure on one of the bipolar plates contacts the anode metal mesh of the frame assembly.

[0021] Furthermore, the position where the anode metal mesh contacts the top of the protruding structure is a closed surface, and the anode metal mesh comprises a stamped titanium mesh;

[0022] Alternatively, the anode metal mesh includes a stretched titanium mesh and a woven titanium mesh, the woven titanium mesh is in contact with the top of the protruding structure, and the stretched titanium mesh is stacked on a side of the woven titanium mesh away from the protruding structure.

[0023] The present application also discloses an electrolytic cell, comprising an upper cover plate, a lower cover plate and a plurality of electrolytic chambers;

[0024] A plurality of electrolysis chambers are installed between the upper cover plate and the lower cover plate.

[0025] As can be seen from the above technical solutions, the bipolar plate designed in this application, by designing multiple evenly spaced protrusions on the plate body, can form corresponding flow channels between adjacent protrusions, which plays a role in flow channel diversion. At the same time, the frustum-shaped protrusion structure can increase the contact area between the bipolar plate and the anode metal mesh compared to other spherical or elliptical protrusion structures, reducing layer resistance and operating voltage. The anode metal mesh is designed as a stamped titanium mesh with a closed surface, which can ensure water flow channels while increasing the area of electrical conduction. Compared with the flat plate structure design, there is no need to add multiple layers of sintered titanium mesh, which effectively reduces the difficulty and cost of process assembly. In addition, a buffer zone with a zigzag profile is designed between the protrusions near the water outlet or water inlet on the plate body. Utilizing this buffer zone design, it can reduce water / air inlet resistance and water / air outlet resistance, while ensuring the effective contact area on the plate body and improving hydrogen production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0027] Figure 1 A top view of a bipolar plate provided in this application;

[0028] Figure 2 A three-dimensional diagram of a bipolar plate provided in this application;

[0029] Figure 3 A partial structural cross-sectional view of an electrolysis chamber provided in this application;

[0030] Figure 3a This is a schematic diagram of the structure of a stamped titanium mesh for an electrolysis chamber provided in this application;

[0031] Figure 4 A comparison chart of characteristic curves between a bipolar plate provided in this application and a bipolar plate with a traditional flat plate structure;

[0032] Figure 5a A color version of the temperature distribution diagram of a bipolar plate provided in this application;

[0033] Figure 5b A grayscale temperature distribution diagram of a bipolar plate provided in this application;

[0034] Figure 6a This is a color version of the temperature distribution diagram of the bipolar plate with a traditional flat plate structure;

[0035] Figure 6b This is a grayscale version of the temperature distribution diagram of a bipolar plate with a traditional flat plate structure;

[0036] Figure 7 A comparison chart of hydrogen production between a bipolar plate provided in this application and a bipolar plate with a traditional flat plate structure;

[0037] Figure 8 A comparison chart of water seepage between a bipolar plate provided in this application and a bipolar plate with a traditional flat plate structure;

[0038] Figure 9a A color version of the pressure distribution diagram of a bipolar plate provided in this application;

[0039] Figure 9b A grayscale pressure distribution diagram of a bipolar plate provided in this application;

[0040] Figure 10a This is a color version of the pressure distribution diagram of the traditional flat-plate bipolar plate;

[0041] Figure 10b This is a grayscale version of the pressure distribution diagram of a bipolar plate with a traditional flat plate structure;

[0042] Figure 11a A color version of the flow velocity distribution diagram of a bipolar plate provided in this application;

[0043] Figure 11b A grayscale flow velocity distribution diagram of a bipolar plate provided in this application;

[0044] Figure 12a The color version of the flow velocity distribution diagram of the traditional flat-plate bipolar plate;

[0045] Figure 12b The grayscale version of the flow velocity distribution diagram of the traditional flat-plate bipolar plate;

[0046] In the figure: 1. Plate body; 11. Water inlet; 12. Water outlet; 13. Raised structure; 14. Buffer zone; 2. Frame assembly; 21. Frame; 22. Frame sealing layer; 23. Membrane electrode sealing layer; 24. Cathode stainless steel mesh; 25. Cathode stainless steel felt; 26. Cathode titanium felt; 27. Membrane electrode; 28. Anode titanium felt; 29. Anode metal mesh; 100. Closing surface. DETAILED DESCRIPTION

[0047] The following will clearly and completely describe the technical solutions of the embodiments of the present application in conjunction with the accompanying drawings. Obviously, the embodiments described are only part of the embodiments of the present application, not all of them. Based on the embodiments of the present application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the embodiments of the present application.

[0048] In the description of the embodiments of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, they should not be understood as limiting the embodiments of the present application. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and should not be understood as indicating or implying relative importance.

[0049] In the description of the embodiments of the present application, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, replaceable connections, or integral connections. They can also refer to mechanical connections or electrical connections. They can also refer to direct connections or indirect connections through an intermediate medium. They can also refer to internal connections between two components. For those skilled in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to specific circumstances.

[0050] The embodiments of the present application disclose a bipolar plate.

[0051] See also Figure 1 , an embodiment of a bipolar plate provided in the embodiments of the present application includes:

[0052] Plate body 1;

[0053] A portion of the plate body 1 arches away from one side of the plate body to form a raised structure 13. Multiple raised structures 13 are evenly spaced. Adjacent raised structures form corresponding flow channels, which act as flow diversion channels. Compared to a flat plate design, this eliminates the need for multiple layers of sintered titanium mesh, significantly reducing assembly complexity and cost.

[0054] A buffer zone 14 with a zigzag-like profile is formed between the raised structures 13 near the water outlet 12 or water inlet 11 on the plate body 1. It is understood that the buffer zone 14 has a sawtooth-like profile with multiple spaced notches. Compared to a straight profile, this notch design can reduce water / air inlet and outlet resistance, while ensuring effective contact area on the plate body 1 and improving hydrogen production efficiency.

[0055] The above is an embodiment of a bipolar plate provided in the embodiment of the present application. The following is an embodiment of a bipolar plate provided in the embodiment of the present application. For details, please refer to Figures 1 to 3 、 Figure 3a 、 Figure 4 、 Figure 5a 、 Figure 5b 、 Figure 6a 、 Figure 6b 、 Figure 7 、 Figure 8 、 Figure 9a 、 Figure 9b 、 Figure 10a 、 Figure 10b 、 Figure 11a 、 Figure 11b 、 Figure 12a 、 Figure 12b .

[0056] Based on the solution of the above embodiment 1:

[0057] Furthermore, the top of the raised structure 13 is provided with a flat surface. This flat surface ensures better contact between the raised structure 13 and the anode metal mesh 29 during use, increasing the effective contact area. Specifically, the raised structure 13 can be a frustum-shaped structure, with an isosceles trapezoidal cross-section. Furthermore, compared to other spherical or elliptical raised structures, the frustum-shaped raised structure can increase the contact area between the bipolar plate and the anode metal mesh, thereby reducing the layer resistance and operating voltage.

[0058] Furthermore, assuming that the thickness of the electrode body 1 is t and the protrusion height is H, it can be designed to be 3t≤H≤4t. Within this designed height range, the protrusion structures 13 can form flow channels that meet the requirements.

[0059] Furthermore, assuming that the top plane diameter of the protruding structure 13 is D, it can be designed as 4H≤D≤4.5H; within this design range, the contact area between the protruding structure 13 and the anode metal mesh 29 can be optimized so that the contact area between the protruding structure 13 and the anode metal mesh 29 is maximized.

[0060] Assume that the total top planar area of all protrusion structures 13 is S 总 , and the area of one side of the plate body 1 when there is no protruding structure 13 is S 初, which can be designed to be 0.4S 初 ≤S 总 ≤0.5S 初 . If the plate size is 100mm*100mm, then S 初 =10000mm 2 , then S 总 Can be controlled at 4000mm 2 ~5000mm 2 .

[0061] Furthermore, a rectangular array design of the plurality of protrusion structures 13 is taken as an example.

[0062] Assuming that the array spacing between adjacent protrusion structures 13 in the first array direction is B1, it can be designed to be 6H ≤ B1 ≤ 6.5H. Assuming that the array spacing between adjacent protrusion structures 13 in the second array direction is B2, it can be designed to be 5.5H ≤ B2 ≤ 6H. Within this array spacing design range, it can be optimized to maximize the contact area between the protrusion structures 13 and the anode metal mesh 29.

[0063] It should be noted here that the above array spacing design can have two situations:

[0064] The direction from the water outlet 12 on the plate body 1 to the water inlet 11 is used as the preset direction:

[0065] Case 1: The first array direction is parallel to the preset direction, and the second array direction is perpendicular to the preset direction;

[0066] Second case: the second array direction is parallel to the preset direction, and the first array direction is perpendicular to the preset direction.

[0067] Furthermore, taking the convex structure 13 as a frustum-shaped design as an example, assuming that the slope of the convex structure 13 is θ, it can be designed to be 45°≤θ≤60°.

[0068] The above parameter designs can be considered together to achieve better results.

[0069] Furthermore, take the case where the plurality of protrusion structures 13 are in the form of a rectangular array as an example.

[0070] In order to form a buffer zone 14 with a zigzag profile between the protruding structures 13 near the water outlet 12 or the water inlet 11 on the plate body 1, the following design may be employed:

[0071] The protrusion structures 13 in two adjacent rows are staggered and arranged, where the row direction is parallel to the above-mentioned preset direction.

[0072] Of course, the raised structures 13 in this application can also be arranged in other arrays. If the electrode body 1 is circular, then the raised structures 13 can be a circular array. First, the raised structures 13 are distributed to form multiple radial rows. The multiple radial rows are distributed circumferentially around a circle to form a circular array. In this design, it is only necessary to stagger the raised structures 13 in the adjacent rows corresponding to the water outlet 12 or water inlet 11. It is also possible to form a buffer zone 14 with a zigzag profile between the raised structures 13 near the water outlet 12 or water inlet 11 on the electrode body 1.

[0073] like Figure 3 As shown, the present application also discloses an electrolysis chamber, including a frame assembly 2 and two bipolar plates of the above-mentioned embodiment 1 or embodiment 2.

[0074] Two bipolar plates are mounted on both sides of the frame assembly 2 ; the top of the raised structure 13 on one of the bipolar plates contacts the anode metal mesh 29 of the frame assembly 2 .

[0075] The structure of the frame assembly 2 can refer to existing structural designs and specifically includes two frames 21, a cathode stainless steel mesh 24, a cathode stainless steel felt 25, a cathode carbon felt, a membrane electrode 27, an anode titanium felt 28, and an anode metal mesh 29. The two frames 21 are stacked from bottom to top, and the anode metal mesh 29, anode titanium felt 28, membrane electrode 27, cathode titanium felt 26, cathode stainless steel felt 25, and cathode stainless steel mesh 24 are stacked in sequence from bottom to top and installed in the two frames 21. Two bipolar plates are installed on the upper and lower sides of the two frames 21. A frame sealing layer 22 is provided between the bipolar plate in contact with the anode metal mesh 29 and the corresponding frame 21. A frame sealing layer 22 is also provided between the other bipolar plate and the corresponding frame 21. A membrane electrode sealing layer 23 is provided between the two side surfaces of the membrane electrode 27 and the corresponding two frames 21.

[0076] Furthermore, thanks to the design of the bipolar plate of the present application, there is no need to add multiple layers of sintered titanium mesh (multi-layer woven titanium mesh). For this reason, the anode metal mesh 29 can be designed to include a stamped titanium mesh. Compared with the multi-layer sintered titanium mesh, the stamped titanium mesh can greatly reduce the manufacturing cost and assembly difficulty, and can achieve a tighter support effect.

[0077] Furthermore, the position where the stamped titanium mesh contacts the top plane of the protruding structure 13 is designed as a closed surface 100, such as Figure 3aAs shown, the locations on the stamped titanium mesh corresponding to the top plane of the raised structure 13 are not perforated; holes are only provided outside of the contact area. This design ensures good contact with the top plane of the boss structure of the intermediate flow channel plate, increasing the effective contact area. It also reduces the increase in resistance and unstable layer voltage caused by poor contact, which can affect the performance of the entire electrolytic cell, leading to high energy consumption and low efficiency.

[0078] The anode metal mesh 29 may also include a stretched titanium mesh and a woven titanium mesh. The woven titanium mesh contacts the top of the protruding structure 13 , and the stretched titanium mesh is stacked on a side of the woven titanium mesh away from the protruding structure 13 .

[0079] The woven titanium mesh in this application is a single-layer woven titanium mesh, which is in contact with the top plane of the raised structure 13. The stretched titanium mesh is in contact with the side of the single-layer woven titanium mesh facing away from the raised structure 13, thereby increasing the effective conductive contact area between the anode metal mesh 29 and the top of the bipolar plate raised structure 13. At the same time, the stretched titanium mesh can further improve the support tightness, enhance the function and save material costs.

[0080] The present application also discloses an electrolytic cell, which is characterized by comprising an upper cover plate (not shown in the figure), a lower cover plate (not shown in the figure) and a plurality of electrolytic chambers; the plurality of electrolytic chambers are installed between the upper cover plate and the lower cover plate.

[0081] from Figure 4 It can be seen that the current density of the bipolar plate designed in the present application is basically consistent with the current density of the bipolar plate with the original flat plate structure.

[0082] from Figure 5a as well as Figure 6a It can be seen that the temperature distribution uniformity of the bipolar plate designed in the present application is basically consistent with that of the original bipolar plate with a flat plate structure.

[0083] from Figure 7 It can be seen that the hydrogen production of the electrolyzer using the bipolar plates designed in this application is higher than that of the original flat plate structure.

[0084] from Figure 8 It can be seen that the water seepage of the electrolytic cell using the bipolar plates designed in this application is lower than that of the original flat plate structure.

[0085] from Figure 9a as well as Figure 10a It can be seen that during steady-state operation, the pressure drop of the bipolar plate designed using the present application is significantly lower than that of the original flat-plate structure bipolar plate, and the pressure drop is reduced from the original 0.13 bar to 0.06 bar, and the water flow field water resistance is significantly reduced.

[0086] from Figure 11aas well as Figure 12a It can be seen that the flow velocity distribution uniformity of the bipolar plate designed in the present application is basically consistent with that of the original bipolar plate with a flat plate structure.

[0087] After analysis and verification, the bipolar plate designed in this application can achieve further beneficial effects of increasing hydrogen production, reducing water seepage and pressure drop while maintaining the same current density, temperature distribution uniformity, and flow velocity distribution uniformity as the original structure.

[0088] The above is a detailed introduction to a bipolar plate, an electrolysis chamber, and an electrolytic cell provided in the present application. For a person skilled in the art, according to the ideas of the embodiments of the present application, there may be changes in the specific implementation methods and application scopes. In summary, the contents of this specification should not be understood as limiting the present application.

Claims

1. An electrolysis chamber, characterized in that: The electrolysis chamber is an electrolysis chamber of a PEM electrolyzer, comprising a frame assembly (2) and two bipolar plates; The bipolar plate comprises a plate body (1); A portion of the plate body (1) arches in a direction away from one side thereof to form a convex structure (13), the plate body (1) having an opposite anode surface and a cathode surface, the convex structure (13) arching from the cathode surface toward the anode surface, the convex structure being formed on the anode surface, and a corresponding depression being formed on the cathode surface; The protrusion structures (13) are multiple and evenly spaced, and flow channels are formed between adjacent protrusion structures (13) to achieve flow channel diversion. A buffer zone (14) with a zigzag profile is formed between the protruding structures (13) near the water outlet (12) or the water inlet (11) on the plate body (1), and the buffer zone (14) has a recessed design with multiple intervals; The protruding structures (13) in two adjacent rows are staggered so that a buffer zone (14) with a zigzag profile is formed between the protruding structures (13) near the water outlet (12) or the water inlet (11) on the electrode body (1); The top of the raised structure (13) is provided with a flat surface; The two bipolar plates are mounted on both sides of the frame assembly (2); The top of one of the raised structures (13) on the bipolar plate contacts the anode metal mesh (29) of the frame assembly (2), and the position where the anode metal mesh (29) contacts the top of the raised structure (13) is a closed surface (100).

2. The electrolysis chamber according to claim 1, characterized in that The protruding structure (13) is in the shape of a frustum.

3. The electrolysis chamber according to claim 2, characterized in that The thickness of the electrode body (1) is t, and the height of the protruding structure (13) is H, wherein 3t≤H≤4t.

4. The electrolysis chamber according to claim 3, characterized in that The top plane diameter of the protruding structure (13) is D, wherein 4H≤D≤4.5H; The sum of the top plane areas of all the protruding structures (13) is S 总 The area of one side of the plate body (1) when not provided with the protruding structure (13) is S 初 , of which 0.4S 初 ≤S 总 ≤0.5S 初 .

5. The electrolysis chamber according to claim 4, characterized in that The plurality of protruding structures (13) are arranged in a rectangular array; The array spacing between adjacent protrusion structures (13) in the first array direction is B1, wherein 6H≤B1≤6.5H; The array spacing between adjacent protruding structures (13) in the second array direction is B2, wherein 5.5H≤B2≤6H.

6. The electrolysis cell according to any one of claims 2 to 5, characterized in that The slope of the protruding structure (13) is θ, wherein 45°≤θ≤60°.

7. The electrolysis chamber according to claim 1, characterized in that The plurality of protruding structures (13) are arranged in a rectangular array.

8. The electrolysis chamber according to claim 1, characterized in that The anode metal mesh (29) comprises a stamped titanium mesh; Or the anode metal mesh (29) includes a stretched titanium mesh and a woven titanium mesh, the woven titanium mesh is in contact with the top of the protruding structure (13), and the stretched titanium mesh is stacked on a side of the woven titanium mesh away from the protruding structure (13).

9. An electrolytic cell, characterized in that The electrolytic cell is a PEM electrolytic cell, comprising an upper cover plate, a lower cover plate, and a plurality of electrolysis chambers according to any one of claims 1 to 8; A plurality of electrolysis chambers are installed between the upper cover plate and the lower cover plate.

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