PEM bipolar plate, single cell and electrolytic cell

Abstract

The invention discloses a PEM bipolar plate, a single cell and an electrolytic bath, and relates to the technical field of electrolytic baths, the PEM bipolar plate comprises a square bipolar plate body, the middle of one side of the bipolar plate body is concaved inwards to form an anode runner region, and the middle of the other side of the bipolar plate body is concaved inwards to form a cathode runner region; and two flow channel ports which are arranged at an interval are formed in each of four side edges of the bipolar plate body. According to the bipolar plate, water can enter the anode side and the cathode side of the bipolar plate body at the same time, the water amount is kept consistent, heat can be conducted to the maximum extent, meanwhile, the flowing uniformity of fluid in the flow channels on the two sides is guaranteed, the hydrogen transmission efficiency is improved, and the electrolysis efficiency and the working performance are guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical field of hydrogen production, and particularly to a PEM bipolar plate, a single cell and an electrolyzer. Background Art

[0002] As one of the important devices for green hydrogen production, the PEM (Proton Exchange Membrane) electrolyzer has the advantages of compact structure, small floor area, high electrolysis efficiency, and the ability to obtain high-purity hydrogen under high-pressure conditions.

[0003] As one of the important components inside the PEM electrolyzer, the bipolar plate plays roles including uniformly transporting and distributing reactants and products, collecting current, conducting electrons, conducting heat, and controlling the uniform temperature of the reaction zone. Therefore, it needs to have good electron transport efficiency, heat conduction efficiency, excellent mechanical properties, and a uniformly distributed flow field.

[0004] For existing bipolar plates, such as a bipolar plate and a PEM electrolyzer disclosed in Patent No. CN202311724840.8, a hydrogen flow channel and a water flow channel are provided inside the bipolar plate body; the hydrogen flow channel communicates the cathode surface with the hydrogen outlet; the water flow channel communicates the anode surface with the water inlet and outlet. Since it can only be fed with water from one side, its thermal conductivity is poor, the hydrogen transport efficiency is not high, which has a greater impact on the electrolysis efficiency and performance, and it is difficult to be applied to electrolyzers with large plate types and high current densities. Summary of the Invention

[0005] The problem solved by the present invention is how to improve the thermal conductivity of the reaction zones on both sides of the bipolar plate, improve the hydrogen transport efficiency, ensure the electrolysis efficiency and working performance, so as to be applicable to the application of electrolyzers with large plate types and high current densities.

[0006] In a first aspect, the present invention provides a PEM bipolar plate, which includes a square bipolar plate body, and is characterized in that: A concave anode flow channel area is formed in the middle of one side of the bipolar plate body, and a concave cathode flow channel area is formed in the middle of the other side of the bipolar plate body. Two spaced flow ports are provided along the four sides of the bipolar plate body. The two flow ports near the lower right corner of the bipolar plate body are the anode inlets, and the two flow ports near the upper left corner of the bipolar plate body are the anode outlets. The inlet of the anode flow channel area is connected to the anode inlet on the right side of the lower end of the bipolar plate body, and the outlet of the anode flow channel area is connected to the anode outlet on the left side of the upper end of the bipolar plate body. The two flow ports near the lower left corner of the bipolar plate body are the cathode inlets, and the two flow ports near the upper right corner of the bipolar plate body are the cathode outlets. The inlet of the cathode flow channel area is connected to the cathode inlet at the lower end of the left side of the bipolar plate body, and the outlet of the cathode flow channel area is connected to the cathode outlet at the upper end of the right side of the bipolar plate body.

[0007] Preferably, the flow channels in the anode flow channel region are arranged vertically, the flow channels in the cathode flow channel region are arranged horizontally, and the flow path length of the flow channels in the anode flow channel region is equal to that of the flow channels in the cathode flow channel region, where the flow path length refers to the path length that the fluid flows through the flow channels.

[0008] Preferably, the flow channels in the anode flow channel region are parallel flow channels, and the flow channels in the anode flow channel region include vertical distribution flow channels on both sides and a first horizontal flow channel in the middle. The vertical distribution flow channels are respectively connected to the anode inlet and the anode outlet. The flow channels in the cathode flow channel region are parallel flow channels, and the flow channels in the cathode flow channel region include horizontal distribution flow channels at both ends, a middle vertical flow channel, and a second horizontal flow channel. The second horizontal flow channel is arranged between the two middle vertical flow channels, and the two middle vertical flow channels are also respectively connected to the two horizontal distribution flow channels. The two horizontal distribution flow channels are also respectively connected to the cathode inlet and the cathode outlet.

[0009] Preferably, sealing grooves with the same structure are respectively arranged on both sides of the bipolar plate body. The sealing groove on one side of the bipolar plate body is 90° different from the sealing groove on the other side. The sealing groove includes a flow port sealing groove arranged around each flow port of the bipolar plate body and a flow channel region sealing groove arranged on the outer periphery of the flow channel region. Matching sealing glue lines are arranged inside the flow port sealing groove and the flow channel region sealing groove.

[0010] Preferably, the flow channel regions on both sides of the bipolar plate body are processed by the etching flow channel method.

[0011] Preferably, the sizes of all the flow ports are the same and they are symmetrically arranged, and the flow ports are semi-circular.

[0012] In a second aspect, the present invention also provides a single cell, including a PEM bipolar plate as described in any one of the first aspects above.

[0013] Preferably, it further includes a membrane electrode. A plurality of the bipolar plates and a plurality of the membrane electrodes are arranged in an alternating laminated manner. One of the bipolar plates is rotated 180° relative to another adjacent bipolar plate, and one of the membrane electrodes is rotated 90° relative to another adjacent membrane electrode. The anode side of the membrane electrode is connected to the anode side of one of the bipolar plates, and the cathode side of the membrane electrode is connected to the cathode side of the other bipolar plate.

[0014] Preferably, two membrane electrode flow ports are arranged at intervals on four sides close to the membrane electrode, and the membrane electrode flow ports are arranged corresponding to the respective flow ports of the bipolar plate.

[0015] In a third aspect, the present invention provides an electrolytic cell, which includes a single cell as described in the second aspect above.

[0016] The beneficial effects of the PEM bipolar plate of the present invention application are as follows: Since the anode inlet of the anode flow channel area of the bipolar plate body is at the lower right end of the bipolar plate body and the anode outlet is at the upper left end of the bipolar plate body, the fluid flow direction on the anode side is from the lower right to the upper left. While the cathode inlet of the cathode flow channel area of the bipolar plate body is at the lower left side of the bipolar plate body and the cathode outlet is at the upper right side of the bipolar plate body, the fluid flow direction on the cathode side is from the lower left to the upper right. The anode inlet and cathode inlet of the bipolar plate body can intake water simultaneously and the water volume remains consistent. It can not only conduct heat to the maximum extent, but also ensure the flow uniformity of the fluid in the flow channels on both sides, improve the hydrogen transmission efficiency, and ensure the electrolysis efficiency and working performance.

[0017] The beneficial effects of the single cell and electrolytic cell of the present invention application are as follows: The bipolar plates and the membrane electrode interlayer are arranged in a stacked manner. At the same time, two adjacent bipolar plates are arranged with a 180° difference, and two adjacent membrane electrodes are arranged with a 90° difference. This makes the pressure distribution on both sides of the bipolar plates in contact with the membrane electrode more uniform, making the membrane electrode not easily damaged, extending the service life, and saving costs. Description of the Drawings

[0018] Figure 1 It is the A-plane view of the bipolar plate body of the present invention application; Figure 2 It is the B-plane view of the bipolar plate body of the present invention application; Figure 3 For the present invention application Figure 1 The enlarged schematic view of the structure at a in Figure 4 For the present invention application Figure 2 The enlarged schematic view of the structure at b in Figure 5 It is the exploded view of the stacking of a single bipolar plate body and a single membrane electrode of the present invention application; Figure 6 It is the exploded view of the stacking of the membrane electrode and the bipolar plate of the present invention application; Figure 7 It is the cloud diagram of the flow channel pressure distribution on the B plane of the bipolar plate body of the present invention application; Figure 8 It is the cloud diagram of the flow channel pressure distribution on the B plane on both sides of the membrane electrode of the present invention application; Figure 9 It is the cloud diagram of the flow channel pressure distribution on the A plane of the bipolar plate body of the present invention application; Figure 10 It is the cloud diagram of the flow channel pressure distribution on the A plane on both sides of the membrane electrode of the present invention application; Description of the reference numerals: 1. Bipolar plate body; 2. Anode flow channel area; 21. Vertical distribution flow channel; 22. First horizontal flow channel; 3. Cathode flow channel area; 31. Horizontal distribution flow channel; 32. Second horizontal flow channel; 33. Intermediate vertical flow channel; 4. Anode inlet; 5. Cathode inlet; 6. Anode outlet; 7. Cathode outlet; 8. Sealing groove; 81. Flow port sealing groove; 82. Flow channel area sealing groove; 9. Sealing glue line; 10. Membrane electrode; 11. Mounting hole; 12. Connecting hole. Specific embodiments

[0019] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0020] Among them, the same components are denoted by the same reference numerals. It should be noted that the terms "front", "rear", "left", "right", "upper" and "lower" used in the following description refer to the directions in the accompanying drawings of the present application specification, and the terms "bottom surface" and "top surface", "inner" and "outer" respectively refer to facing or away from a specific component. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present application specification, "a plurality" means two or more.

[0021] Next, the present application will be further described in conjunction with the accompanying drawings and embodiments.

[0022] Embodiment 1, as Figure 1 is the front view of the bipolar plate body, which is defined as the A surface, as Figure 2Shown is the back view of the bipolar plate body, which is defined as the B surface. A PEM bipolar plate provided in this embodiment includes a square bipolar plate body 1. The bipolar plate body 1 has two opposite side surfaces (i.e., the A surface and the B surface). A concave anode flow channel area 2 is formed in the middle of one side surface of the bipolar plate body 1, and a concave cathode flow channel area 3 is formed in the middle of the other side surface of the bipolar plate body 1. Two spaced flow ports are provided along the four sides of the bipolar plate body 1. The two flow ports near the lower right corner of the bipolar plate body 1 are the anode inlets 4, and the two flow ports near the upper left corner of the bipolar plate body 1 are the anode outlets 6. The inlet of the anode flow channel area 2 is connected to the anode inlet 4 on the right side of the lower end of the bipolar plate body 1, and the outlet of the anode flow channel area 2 is connected to the anode outlet 6 on the left side of the upper end of the bipolar plate body 1. The two flow ports near the lower left corner of the bipolar plate body 1 are the cathode inlets 5, and the two flow ports near the upper right corner of the bipolar plate body 1 are the cathode outlets 7. The inlet of the cathode flow channel area 3 is connected to the cathode inlet 5 at the lower end of the left side of the bipolar plate body 1, and the outlet of the cathode flow channel area 3 is connected to the cathode outlet 7 at the upper end of the right side of the bipolar plate body 1.

[0023] Since the bipolar plate body 1 of this embodiment is square and both of its side channels can admit water, during use, the anode side can be the A surface or the B surface of the bipolar plate body 1. Correspondingly, the cathode side can be the A surface or the B surface of the bipolar plate body 1. In this way, when stacked with the membrane electrode, it can be freely selected according to actual needs. In this embodiment, as Figure 1The A side of the bipolar plate body shown is defined as the anode side, and the B side is defined as the cathode side. The anode flow channel areas 2 and the cathode flow channel areas 3 on both sides of the bipolar plate body 1 adopt different layout methods. The fluid in the anode flow channel area 2 enters from the anode inlet 4 at the lower right side of the bipolar plate body 1 and then flows out from the anode outlet 6 at the upper left side of the bipolar plate body 1. The flow channel layout method of this anode flow channel area 2 is a vertical method from bottom to top. The fluid in the cathode flow channel area 3 enters from the cathode inlet 5 at the lower end of the left side of the bipolar plate body 1 and then flows out from the cathode outlet 7 at the upper end of the right side of the bipolar plate body 1. The flow channel layout method of this cathode flow channel area 3 is a horizontal method from left to right. Through the mutually perpendicular flow channel layout method, compared with the existing bipolar plates, such as the bipolar plate, PEM electrolyzer, PEM fuel cell, and new energy vehicle disclosed in the patent application number CN202411437587.2, the flow channel layout methods of the reaction areas on the anode side and the cathode side of this bipolar plate are the same, both adopting parallel flow channels arranged in the horizontal direction. At the same time, only pure water can be introduced on the anode side, and only a hydrogen outlet is provided on the cathode side, that is, the anode side is a water flow channel, and the cathode side is a hydrogen flow channel. Due to its single-side water inlet method, the thermal conductivity is poor, and at the same time, the hydrogen transmission efficiency is not high, and the electrolysis efficiency and performance are greatly affected. In this embodiment, the cathode inlet and the anode inlet of the bipolar plate body can achieve the double-side water inlet method, ensuring that the flow field maintains a lower pressure drop during the operation of the electrolyzer, and at the same time having good thermal conductivity, improving the hydrogen transmission efficiency, ensuring the electrolysis efficiency and performance, and being more suitable for the application in large-size and high-current-density electrolyzers.

[0024] Specifically, the bipolar plate of this embodiment adopts the double-side water inlet method, that is, pure water is introduced into the anode flow channel area 2 of the bipolar plate. After a small amount of pure water participates in the reaction, a large amount of other pure water carries oxygen and flows out from the anode outlet 6 of the anode flow channel area 2. Pure water is also introduced into the cathode flow channel area 3 of the bipolar plate. This pure water does not participate in the electrolysis reaction, but can make the hydrogen in the reaction area on this side evenly distributed and the temperature evenly distributed, improving the hydrogen transmission efficiency. In this way, water is introduced into the flow channel areas on both sides of the bipolar plate at the same time, and the water volume on both sides remains the same, which can conduct heat to the greatest extent, control the temperature distribution in the reaction area, improve the gas transmission efficiency, ensure the electrolysis efficiency and performance, and is especially suitable for large-size and high-current-density electrolyzers.

[0025] Preferably, the bipolar plate body 1 can be processed from a titanium plate or a stainless steel plate. In this embodiment, the bipolar plate body 1 is made of a titanium plate. The titanium plate is a whole plate, and the outer side of the titanium plate is treated with PVD platinum plating. The flow channel areas on both sides of it are processed by the etching flow channel method. The thickness of the bipolar plate body 1 is between 2 mm and 3 mm.

[0026] Preferably, the flow channels in the anode flow channel region 2 are arranged vertically, and the flow channels in the cathode flow channel region 3 are arranged horizontally. The along - path distance of the flow channels in the anode flow channel region 2 is equal to that of the flow channels in the cathode flow channel region 3. Here, the along - path distance refers to the path length that the fluid flows through the flow channel. This makes the pressure drops on both sides of the bipolar plate body basically the same.

[0027] Specifically, the flow channels in the anode flow channel region 2 are arranged in a parallel - flow - channel arrangement. The parallel - flow - channel design can ensure that the entire flow field maintains a relatively low pressure drop during the operation of the electrolytic cell, strengthen mass transfer and heat transfer, and increase the reaction rate on the anode side. The flow channels in the anode flow channel region 2 include vertical distribution channels 21 on both sides and a first horizontal flow channel 22 in the middle. The vertical distribution channels 21 on both sides are respectively connected to the anode inlet 4 and the anode outlet 6. The ratio of the number of flow channels of the first horizontal flow channel 22 to that of the vertical distribution channels 21 is 1:1 - 3:1. In this embodiment, as shown in the enlarged structural schematic diagram of part of the flow channels in the anode flow channel region in Figure 3, the number of flow channels of the first horizontal flow channel 22 of the bipolar plate is three times that of the vertical distribution channels 21. Since the anode flow channel region 2 is used to transport pure water and oxygen generated by the electrochemical reaction, and the number of flow channels of the first horizontal flow channel 22 is more than that of the vertical distribution channels 21, by increasing the number of parallel flow channels and having them in a parallel connection form, the contact area can be increased, the flow resistance can be reduced, the pressure loss can be lowered, which helps to promote heat transfer, maintain temperature stability during operation, and avoid performance degradation caused by local overheating.

[0028] Specifically, the flow channels in the cathode flow channel region 3 are arranged in a parallel - flow - channel arrangement. The flow channels in the cathode flow channel region 3 include horizontal distribution channels 31 at both ends, a middle vertical flow channel 33, and a second horizontal flow channel 32. The second horizontal flow channel 32 is arranged between the two middle vertical flow channels 33. The two middle vertical flow channels 33 are also respectively connected to the two horizontal distribution channels 31. The two horizontal distribution channels 31 are respectively connected to the cathode inlet 5 and the cathode outlet 7. Among them, the flow channels of the horizontal distribution channels 31 are in one - to - one correspondence with those of the middle vertical flow channel 33, and the connection between the flow channels of the horizontal distribution channels 31 and those of the middle vertical flow channel 33 is connected through an arc - shaped flow channel. The ratio of the number of flow channels of the second horizontal flow channel 32 to that of the middle vertical flow channel 33 is 3:1 - 1:1, and the connection between the flow channels of the second horizontal flow channel 32 and those of the middle vertical flow channel 33 is connected through an arc - shaped flow channel. In this embodiment, as Figure 4As can be seen from the enlarged structural schematic diagram of a partial flow channel in the cathode flow channel region, the number of flow channels in the second horizontal flow channel 32 is three times that of the middle vertical flow channel 33. The cathode flow channel region 3 is used to transport pure water and hydrogen. Since the number of flow channels in the second horizontal flow channel 32 is more than that of the middle vertical flow channel 33, by increasing the number of parallel flow channels and having them in a parallel connection form, the contact area can be increased, the flow resistance can be reduced, the pressure loss can be decreased, which helps to promote heat transfer and maintain the temperature stability of the electrolytic cell during operation, and avoid performance degradation caused by local overheating.

[0029] Since the along - distance of the flow channels in the anode flow channel region 2 is equal to that of the flow channels in the cathode flow channel region 3, although the flow channels in the cathode flow channel region 3 (B side) of the bipolar plate body 1 have two more bends than the flow channels in its anode flow channel region 2 (A side), however, due to the equal along - distance, the resulting pressure drop is very small, so that the pressure drops of the flow channels in the anode flow channel region (A side) and the cathode flow channel region (B side) are basically the same.

[0030] Preferably, for each flow port provided on the bipolar plate body 1, the flow port includes two anode inlets 4, two anode outlets 6, two cathode inlets 5, and two cathode outlets 7. Each flow port is of the same size and symmetrically arranged. The flow port can adopt structures such as circular, strip - shaped, square, etc. In this embodiment, the flow port is set to be semi - circular, which can ensure uniform pressure at the port during sealing and ensure the sealing performance.

[0031] Preferably, as Figure 5 As can be seen from the explosion diagram of the stacking of a single bipolar plate body and a single membrane cell shown, sealing grooves 8 are respectively provided on both sides of the bipolar plate body 1. The structures of the sealing grooves 8 on both sides are exactly the same, and the sealing groove 8 on one side of the bipolar body 1 is 90° different from the sealing groove 8 on the other side of the bipolar plate body 1. Since the bipolar plate body 1 is a square structure and the sizes of its respective flow ports are the same and symmetrically arranged, the sealing glue lines on its two sides also differ by 90°. During use, the anode flow channel region 2 and the cathode flow channel region 3 of the bipolar plate body 1 can be defined according to the actual situation, that is, the anode flow channel region 2 on the A side can be defined as the cathode - side flow channel region, or it can be defined as the anode flow channel region, and the same applies to the B side.

[0032] Specifically, the sealing groove 8 includes a flow port sealing groove 81 provided circumferentially around each flow port (i.e., the anode inlet 4, the cathode inlet 5, the anode outlet 6, and the cathode outlet 1) of each bipolar plate body 1 on each side, and a flow channel area sealing groove 82 provided on the outer periphery of the flow channel area (the anode flow channel area 2 or the cathode flow channel area 3). A matching sealant line 9 is provided inside the flow port sealing groove 81 and the flow channel area sealing groove 82. The flow port sealing groove 81 and the flow channel area sealing groove 82 are internally provided with protruding strips arranged at intervals. The sealant line 9 is arranged inside the sealing groove. Then, a double-layer sealant line is adopted. The openings corresponding to the protruding strips between the two layers of sealant lines are connected by short sealant lines. This can not only ensure the sealing effect and prevent risks such as air leakage and leakage, but also ensure the sealing performance when any one layer of the double-layer sealant line is damaged. At the same time, the sealing groove 8 on one side of the bipolar body 1 is 90° different from the sealing groove 8 on the other side of the bipolar plate body 1. This setting is to ensure uniform pressure distribution when stacked with the membrane electrode, which will be described in detail in the following single cell.

[0033] Embodiment 2. This embodiment provides a single cell, including the above-mentioned PEM bipolar plate. Its advantages are the same as those of the PEM bipolar plate and will not be elaborated here.

[0034] Preferably, it further includes a membrane electrode 10. A plurality of bipolar plates and a plurality of membrane electrodes 10 are arranged in an alternating laminated manner. One bipolar plate rotates 180° relative to another adjacent bipolar plate, and one membrane electrode 10 rotates 90° relative to another adjacent membrane electrode 10. For each membrane electrode 10, the anode side of the membrane electrode 10 is connected to the anode side of one bipolar plate, and the cathode side of the membrane electrode 10 is connected to the cathode side of another bipolar plate.

[0035] Specifically, as Figure 6 shown is an exploded view of the stacking of two membrane electrodes and three bipolar plates. The three bipolar plates in this figure are named the No. 1 bipolar plate, the No. 2 bipolar plate, and the No. 3 bipolar plate from left to right, and the two membrane electrodes are named the No. 1 membrane electrode and the No. 2 membrane electrode from left to right. At the same time, the fluid flow directions of the bipolar plates in this figure are marked. The solid arrows are the fluid flow directions on the front side of the bipolar plate, and the dashed arrows are the fluid flow directions on the back side of the bipolar plate. From the above structure of the bipolar plate, it can be seen that either side of the two sides of the bipolar plate can be arbitrarily selected as the anode side and the other side as the cathode side as needed. When stacking the single cells, the cathode side of the No. 1 membrane electrode is connected to the cathode side (B side) of the No. 1 bipolar plate, the anode side of the No. 1 membrane electrode is connected to the anode side (B side) of the No. 2 bipolar plate, the cathode side of the No. 2 membrane electrode is connected to the cathode side (A side) of the No. 2 bipolar plate, and the anode side of the No. 2 membrane electrode is connected to the anode side (A side) of the No. 3 bipolar plate. Among them, the No. 2 bipolar plate rotates 180° relative to the No. 1 bipolar plate, and the No. 2 membrane electrode rotates 90° relative to the No. 1 membrane electrode.

[0036] During the stacking process of the membrane electrode, its anode side is connected to the anode side of a bipolar plate, and its cathode side is connected to the cathode side of another bipolar plate. Since the flow field arrangement forms on the anode side and cathode side of the existing bipolar plates are different, and only single-side water inlet is available, with the anode side being the water flow channel and the cathode side generally being the hydrogen channel, the pressures received by the membrane electrode in different regions are different. This causes the stress distribution of the membrane electrode during use to be uneven, and the membrane electrode is prone to defects such as cracks and breakages at the pressure concentration sites. These defects will gradually expand with the increase of the use time, ultimately leading to the failure of the membrane electrode and shortening the service life of the electrolytic cell.

[0037] In the second embodiment, through this arrangement, it can be known that for the cathode side of the No. 1 membrane electrode, the fluid flow direction on the cathode side (B surface) of the No. 1 bipolar plate in contact with it is the horizontal direction from its lower left to upper right. For the anode side of the No. 1 membrane electrode, the fluid flow direction on the anode side (B surface) of the No. 2 bipolar plate in contact with it is the horizontal direction from its lower right to upper left, as Figure 7 shown in the pressure distribution nephogram of the flow channels on the B surface of the bipolar plate body, as Figure 8 shown in the pressure distribution nephogram on both sides of the No. 1 membrane electrode when both sides are the flow channels on the B surface of the bipolar plate (the membrane electrode is not shown), it can be known that the pressure borne by the No. 1 membrane electrode is uniform; for the cathode side of the No. 2 membrane electrode, the fluid flow direction on the cathode side (A surface) of the No. 2 bipolar plate in contact with it is the vertical direction from its lower left to upper right. For the anode side of the No. 2 membrane electrode, the fluid flow direction on the anode side (A surface) of the No. 2 bipolar plate in contact with it is the vertical direction from its lower right to upper left, as Figure 9 shown in the pressure distribution nephogram of the flow channels on the A surface of the bipolar plate body, as Figure 10 shown in the pressure distribution nephogram on both sides of the No. 1 membrane electrode when both sides are the flow channels on the A surface of the bipolar plate (the membrane electrode is not shown), it can be known that the pressure borne by the No. 2 membrane electrode is uniform. In summary, by adopting the single-cell stacking arrangement method in the second embodiment and the different flow channel form designs on the A surface and B surface of the bipolar plate, the pressures at the same positions on both sides of a single membrane electrode are approximately the same, thereby preventing the membrane electrode from being pierced by excessive pressure differences and effectively extending the service life of the membrane electrode 10. At the same time, both sides of the bipolar plate on both sides of the membrane electrode are the A surface or the B surface at the same time, and the membrane electrode is rotated at a corresponding angle (90° rotation), so that the glue lines on both sides of the membrane electrode can be completely aligned to ensure the sealing effect.

[0038] Preferably, mounting holes 11 are provided at the four corners of the bipolar plate body 1, and corresponding connection holes 12 are provided at the corresponding positions of the membrane electrode 10. Through the corresponding connection of the mounting holes 11 and the connection holes 12, it is convenient to assemble the bipolar plate body 1 and the membrane electrode 10, improving the assembly accuracy.

[0039] Embodiment 3, this embodiment provides an electrolytic cell, including the above-mentioned single cell, and its advantages are the same as those of the PEM bipolar plate and single cell, which will not be repeated here.

[0040] The above is only a preferred embodiment of the present invention, and the present invention is not limited to the above embodiments. It is understood that other improvements and changes directly derived or associated by those skilled in the art without departing from the spirit and concept of the present invention should be considered to be included in the protection scope of the present invention.

[0041] As mentioned above, although the present invention has been shown and described with reference to specific preferred embodiments, it should not be interpreted as limiting the present invention itself. Various changes can be made to it in form and detail without departing from the spirit and scope of the present invention defined in the appended claims.

Claims

1. A PEM bipolar plate, which comprises a square bipolar plate body, characterized in that, One side of the bipolar plate body is recessed in the middle to form an anode flow channel area, and the other side of the bipolar plate body is recessed in the middle to form a cathode flow channel area. Two flow ports are arranged at intervals along the four sides of the bipolar plate body. The two flow ports near the lower right corner of the bipolar plate body are anode inlets, and the two flow ports near the upper left corner of the bipolar plate body are anode outlets. The inlet of the anode flow channel area is connected to the anode inlet on the right side of the lower end of the bipolar plate body, and the outlet of the anode flow channel area is connected to the anode outlet on the left side of the upper end of the bipolar plate body. The two flow ports near the lower left corner of the bipolar plate body are cathode inlets, and the two flow ports near the upper right corner of the bipolar plate body are cathode outlets. The inlet of the cathode flow channel area is connected to the cathode inlet at the lower end of the left side of the bipolar plate body, and the outlet of the cathode flow channel area is connected to the cathode outlet at the upper end of the right side of the bipolar plate body.

2. The PEM bipolar plate according to claim 1, characterized in that, The flow channels in the anode flow channel area are arranged vertically, and the flow channels in the cathode flow channel area are arranged horizontally. The along - path distance of the flow channels in the anode flow channel area is equal to the along - path distance of the flow channels in the cathode flow channel area, where the along - path distance refers to the path length that the fluid flows through the flow channel.

3. A PEM bipolar plate according to claim 2, characterized in that, The flow channels in the anode flow channel area are parallel flow channels. The flow channels in the anode flow channel area include vertical distribution flow channels on both sides and a first horizontal flow channel in the middle. The vertical distribution flow channels are respectively connected to the anode inlet and the anode outlet. The flow channels in the cathode flow channel area are parallel flow channels. The flow channels in the cathode flow channel area include horizontal distribution flow channels at both ends, a middle vertical flow channel, and a second horizontal flow channel. The second horizontal flow channel is arranged between the two middle vertical flow channels. The two middle vertical flow channels are also respectively connected to the two horizontal distribution flow channels, and the two horizontal distribution flow channels are also respectively connected to the cathode inlet and the cathode outlet.

4. A PEM bipolar plate according to claim 3, characterized in that, Sealing grooves with the same structure are respectively arranged on both sides of the bipolar plate body. The sealing groove on one side of the bipolar plate body is 90° different from the sealing groove on the other side. The sealing groove includes a flow - port sealing groove arranged around each flow port of the bipolar plate body and a flow - channel - area sealing groove arranged on the outer periphery of the flow channel area. Matching sealant lines are arranged inside the flow - port sealing groove and the flow - channel - area sealing groove.

5. A PEM bipolar plate according to claim 4, characterized in that, The flow channel areas on both sides of the bipolar plate body are processed by the etching flow channel method.

6. The PEM bipolar plate according to claim 5, characterized in that, Each of the flow ports has the same size and is symmetrically arranged. The flow ports are semicircular.

7. A single cell, characterized in that, A PEM bipolar plate according to any one of the above claims 1 - 6.

8. A single cell according to claim 7, characterized in that, It further includes a membrane electrode. A plurality of the bipolar plates and a plurality of the membrane electrodes are arranged alternately in a stacked manner. One of the bipolar plates is rotated 180° relative to an adjacent bipolar plate, and one of the membrane electrodes is rotated 90° relative to an adjacent membrane electrode. The anode side of the membrane electrode is connected to the anode side of one of the bipolar plates, and the cathode side of the membrane electrode is connected to the cathode side of the other bipolar plate.

9. A single cell according to claim 8, characterized in that, Two membrane - electrode flow ports are arranged at intervals along the four sides of the membrane electrode near it. The membrane - electrode flow ports are arranged corresponding to the respective flow ports of the bipolar plate.

10. An electrolytic cell, characterized in that, Comprising a single cell according to any one of claims 8 and 9 above.

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