Bipolar plate with gas-water separation inner cavity flow channel and fuel cell

Abstract

The invention discloses a bipolar plate with gas-water separation inner cavity flow channels and a fuel cell. The bipolar plate comprises a connecting side surface, a plurality of groups of flow channels and a ridge part, wherein the flow channels are arranged towards a gas diffusion layer and are arranged in a sunken manner; the ridge part is used for separating two adjacent flow channels; each single flow channel comprises a bottom wall, and a first side wall and a second side wall which are arranged on two opposite sides of the bottom wall; the ridge parts and the bottom wall are modified into hydrophilic surfaces, at least part of the area on the first side wall is modified into a hydrophilic area, and the hydrophilic area on the first side wall is communicated with the bottom wall and one ridge part; and other areas of the flow channel are hydrophobic surfaces. According to the bipolar plate disclosed by the invention, liquid water generated by the gas diffusion layer is sucked and stored through hydrophilic modification of the ridge part, the liquid water on the ridge part is conveyed to the bottom wall through the hydrophilic area on the first side wall, the hydrophilic surface of the bottom wall locks water and realizes drainage under the action of airflow, and the hydrophobic surface of the second side wall reduces the invasion risk of the liquid water. And a smooth channel structure is provided for gas to pass through.

Description

Technical Field

[0001] This application relates to the field of fuel cell technology, and in particular to bipolar plates and fuel cells having gas-water separation internal flow channels. Background Technology

[0002] A proton exchange membrane fuel cell (PEMFC) is a device that efficiently converts the chemical energy of reactants into electrical energy. Its main reaction product is water, making it environmentally friendly and a crucial component of future low-carbon energy. The core components of a PEMFC are the membrane electrode assembly (MEA) and bipolar plates. The bipolar plates support the MEA and provide pathways for hydrogen and oxygen, while also draining the liquid water generated at the MEA. Their structural design affects the gas supply and drainage efficiency, directly impacting battery performance. Currently, the flow channels in bipolar plates, designed for compactness, must simultaneously meet gas supply and drainage requirements, making them prone to blockage and affecting both. Conversely, the presence of troughs or raised partitions at the bottom of the flow channels introduces issues with liquid water guidance and increases flow resistance, further reducing drainage efficiency and impacting fuel cell performance.

[0003] Therefore, how to improve the gas supply and drainage performance of bipolar plates and ensure the operational stability of fuel cells is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0004] In view of this, the purpose of this application is to provide a bipolar plate with a gas-water separation internal flow channel to improve the gas supply and drainage performance of the bipolar plate and ensure the operational stability of the fuel cell.

[0005] Another objective of this application is to provide a fuel cell comprising the above-described bipolar plate with a gas-water separation internal flow channel.

[0006] To achieve the above objectives, this application provides the following technical solution:

[0007] A bipolar plate with a gas-water separation internal flow channel, comprising:

[0008] The connecting side is positioned towards the gas diffusion layer, and the connecting side includes multiple sets of recessed flow channels and ridges that separate two adjacent flow channels;

[0009] Each flow channel includes a bottom wall and a first side wall and a second side wall disposed on opposite sides of the bottom wall, the first side wall and the second side wall respectively communicating with a ridge; the ridge and the bottom wall are both modified to be hydrophilic surfaces, at least a portion of the first side wall is modified to be a hydrophilic region, and the hydrophilic region of the first side wall is connected to the bottom wall and a ridge; the other regions of the flow channel are hydrophobic surfaces.

[0010] Preferably, in the bipolar plate with the gas-water separation inner cavity flow channel, a plurality of connecting grooves are provided on the first sidewall, and the two ends of a single connecting groove are respectively connected to the bottom wall and the ridge; the inner wall of the connecting groove is hydrophilic, and the other areas on the first sidewall except for the connecting groove are hydrophobic surfaces.

[0011] Preferably, in the bipolar plate with the gas-water separation inner cavity flow channel, the angle of inclination of the connecting groove on the first sidewall in the length direction of the flow channel is 0-90°, and the end of the connecting groove connected to the bottom wall is located downstream of the liquid flow direction in the flow channel compared to the end of the connecting groove connected to the ridge.

[0012] Preferably, in the bipolar plate with the gas-water separation inner cavity flow channel, a plurality of the connecting grooves are arranged in parallel, the interval between two adjacent connecting grooves on one side edge of the first sidewall is 1.5mm-2.0mm, and the depth of a single connecting groove is 0.04mm-0.06mm.

[0013] Preferably, in the bipolar plate with the gas-water separation inner cavity flow channel described above, the angle between the first sidewall and the bottom wall is 100°-170°.

[0014] Preferably, in the bipolar plate with the gas-water separation inner cavity flow channel, a hydrophobic region is retained on the side of the bottom wall that contacts the second side wall, and the width of the hydrophobic region on the bottom wall is smaller than the width of the hydrophilic region on the bottom wall.

[0015] Preferably, in the bipolar plate with the gas-water separation internal flow channel described above, the hydrophilic regions on the ridge and the first sidewall are modified by laser engraving, coating or chemical etching.

[0016] Preferably, in the bipolar plate with the gas-water separation inner cavity flow channel, the bottom wall is treated with hydrophilicity by laser engraving, and the laser trajectory of the laser engraving process is the same as the direction of liquid flow in the flow channel.

[0017] Preferably, in the bipolar plate with the gas-water separation inner cavity flow channel, the cross-section of the flow channel in its length direction is trapezoidal, rectangular or arc-shaped, and the cross-sectional dimensions of the flow channel in its length direction are the same or different.

[0018] A fuel cell includes a membrane electrode assembly and a bipolar plate having a gas-water separation internal flow channel as described in any of the above embodiments.

[0019] As can be seen from the above technical solution, the bipolar plate with a gas-water separation internal cavity flow channel provided in this disclosure mainly includes a connecting side facing the gas diffusion layer. Multiple sets of flow channels are recessed on the connecting side for transporting gas and liquid water, while adjacent flow channels are separated by ridges. First, the ridges are modified to have a hydrophilic surface. Since the ridges are convex structures relative to the flow channels and are facing the gas diffusion layer, they attract the liquid water generated within the gas diffusion layer and form a primary liquid water storage area through their hydrophilic surface. Further, at least a portion of the first sidewall is modified to a hydrophilic region and connects the bottom wall and the ridges in a direction perpendicular to the bottom wall of the flow channel to form a secondary liquid water transport. The system uses a channel to guide liquid water from the primary liquid water storage area to the bottom wall region of the channel. The bottom wall is modified to be hydrophilic to lock in the liquid water and forms a tertiary liquid water drainage channel through its extended length structure. The above structure forms a tertiary channel for liquid water through the ridge, the first sidewall, and the bottom wall, realizing the orderly attraction, guidance, and discharge of liquid water, thereby reducing the risk of turbulence and chaotic flow of liquid water. At the same time, since the second sidewall remains hydrophobic, gas flows in contact with the second sidewall and forms a separation channel separated from the liquid water, thereby reducing the risk of liquid water clogging the gas. This achieves a structure in which gas and water are separated and flow in an orderly manner in the flow channel of the bipolar plate cavity, improving the gas supply and drainage performance of the bipolar plate and ensuring the stable operation of the fuel cell. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a top view of the connection side of the bipolar plate provided in this disclosure;

[0022] Figure 2 This is a front view of the bipolar plate;

[0023] Figure 3 This is a schematic diagram of a cross-section of a single flow channel;

[0024] Figure 4 This is a schematic diagram of the structure of the first sidewall;

[0025] Figure 5 This is a schematic diagram of the flow of liquid water on the connecting side;

[0026] Figure 6 This is an isometric view of the connected side.

[0027] in:

[0028] 10-Connecting side; 20-Flow channel; 210-Bottom wall; 220-First side wall; 2210-Connecting groove; 230-Second side wall; 30-Ridge. Detailed Implementation

[0029] The core of this application is to disclose a bipolar plate with a gas-water separation internal flow channel to improve the gas supply and drainage performance of the bipolar plate and ensure the operational stability of the fuel cell.

[0030] Another objective of this application is to provide a fuel cell comprising the above-described bipolar plate with a gas-water separation internal flow channel.

[0031] To enable those skilled in the art to better understand the present application, embodiments of the present application will be described below with reference to the accompanying drawings. Furthermore, the embodiments shown below do not limit the scope of the invention as described in the claims. Additionally, the complete contents of the structures represented in the following embodiments are not limited to those necessary for the solution of the invention described in the claims.

[0032] like Figure 1 and Figure 2 As shown, this disclosure provides a bipolar plate with a gas-water separation internal flow channel. Specifically, the bipolar plate has a connecting side 10 disposed towards the gas diffusion layer of the membrane electrode in the fuel cell, and the connecting side 10 is provided with multiple sets of concave flow channels 20 for gas flow and liquid water to pass through. The multiple sets of flow channels 20 cooperate to provide sufficient flow path to improve gas supply and drainage efficiency. Preferably, the multiple sets of flow channels 20 are arranged in parallel to have the same flow direction, so that the gas and liquid water can maintain the same or similar flow posture in different flow channels 20, thereby improving the uniformity of the bipolar plate flow guiding process.

[0033] Adjacent flow channels 20 are connected and separated by ridges 30. Each flow channel 20 includes a bottom wall 210 spaced apart from the ridges 30, and a first side wall 220 and a second side wall 230 disposed opposite each other on both sides of the bottom wall 210. The first side wall 220 and the second side wall 230 are respectively connected to the two ridges 30 connected to both sides of a single flow channel 20. In order to achieve the effect of gas-water separation, both the ridges 30 and the bottom wall 210 are modified to make their surfaces hydrophilic. It should be noted that in the bipolar plate provided in this disclosure, the structural areas that have not undergone hydrophilic modification remain hydrophobic.

[0034] As for the ridge 30, its hydrophilic modification enables it to attract liquid water generated within the gas diffusion layer through its protruding structure relative to the flow channel 20, thus fulfilling the initial discharge requirement of liquid water generated in the gas diffusion layer. Simultaneously, the ridge 30 forms a primary liquid water storage area through its hydrophilic surface. Liquid water generated in the gas diffusion layer will not needlessly enter the flow channel 20, but will instead be attracted and stored by the ridge 30 upon initial contact. As for the bottom wall 210, its modified hydrophilic surface effectively guides liquid flow, providing a clear flow path for liquid water discharge, forming a third-level liquid water flow channel. Based on the above structure, at least a portion of the first sidewall 220 is also hydrophilicized. Simultaneously, the hydrophilic region on the first sidewall 220 connects the bottom wall 210 and the ridge 30, enabling liquid water transport to form a secondary liquid water guiding path. In the above structure, the ridge 30, the first sidewall 220, and the bottom wall 210 each have hydrophilic surfaces and can form a connected three-level liquid water flow path. The three-level structure has independent functions and each performs its own duties. After liquid water is generated in the gas diffusion layer, the primary liquid water storage area of ​​the ridge 30 can attract and store the liquid water, and according to the secondary liquid water guiding path on the first sidewall 220, directly or after the liquid water in the ridge 30 has been stored to a certain extent, guide the liquid water in the ridge 30 to the hydrophilic area on the bottom wall 210. The hydrophilic area on the bottom wall 210 can lock the liquid water, and with the help of the extension structure of the flow channel 20 in the length direction, a three-level liquid water flow path is formed. Figure 5 As shown, the system achieves full-process control over the collection, guidance, and discharge of liquid water in the gas diffusion layer, reducing the risk of turbulence and uncontrolled flow caused by abnormal diffusion of liquid water in the gas diffusion layer within the flow channel 20, and ensuring unobstructed drainage path.

[0035] Meanwhile, it should be noted that other areas of the flow channel 20 remain hydrophobic to facilitate the smooth flow of gas within the flow channel 20 and prevent gas from being obstructed by liquid. Specifically, the second sidewall 230 on the flow channel 20 is entirely a hydrophobic area. For a single flow channel 20, its first sidewall 220, the ridge 30 connected to the first sidewall 220, and part or all of the bottom wall 210 are hydrophilic structures. Liquid water will flow out on the bottom wall 210 and on the side close to the first sidewall 220. The hydrophobic structure of the second sidewall 230 can prevent the intrusion of liquid water and form a certain area of ​​unobstructed space to meet the smooth flow of air. This achieves the formation of a gas-water separation and smooth flow within a single flow channel 20 of the bipolar plate, and realizes effective separation of gas and liquid within the flow channel 20, reducing the accumulation of liquid within the flow channel 20 and reducing the risk of gas passage blockage. This not only improves the drainage performance of the fuel cell but also optimizes the gas supply efficiency, thereby improving the overall performance of the fuel cell.

[0036] To further optimize the above technical solution, achieve more precise guidance of liquid water, and reduce the risk of abnormal liquid water flow, in some embodiments of this disclosure, such as... Figure 1 and Figure 6 As shown, a plurality of connecting grooves 2210 are also provided on the first sidewall 220 of the bipolar plate. The connecting grooves 2210 are preferably configured as recessed structures based on the first sidewall 220, and for a single connecting groove 2210, its two ends are respectively connected to the bottom wall 210 and the ridge 30. Based on this, the inner wall of the connecting groove 2210 is also hydrophilic, so that the connecting groove 2210 can attract and guide liquid water. The liquid water attracted and collected by the ridge 30 can flow smoothly to the bottom wall 210 through the guiding effect of the connecting groove 2210 and be discharged on the bottom wall 210. At the same time, it should be noted that the other areas on the first side wall 220, except for the connecting groove 2210, maintain a hydrophobic structure to further optimize the liquid guidance path, so that the liquid is preferentially guided from the position of the connecting groove 2210 on the first side wall 220. In addition, by arranging the positions of the connecting grooves 2210, the guiding effect of each area on the first side wall 220 can be achieved more evenly. At the same time, the connecting groove 2210 achieves the effect of collecting liquid water, thereby reducing the problem of excessive residence time caused by the large area distribution of liquid water on the first side wall 220 and improving the liquid discharge efficiency.

[0037] Based on the above embodiments, the connecting groove 2210 can be set in any posture on the first side wall 220. It only needs to maintain its connection between the ridge 30 and the bottom wall 210 to meet the flow guiding effect. In order to improve the flow guiding effect of the connecting groove 2210, in some embodiments of this disclosure, the connecting groove 2210 is set as an inclined structure on the first side wall 220. That is, in the length direction of the flow channel 20, the areas at both ends of the connecting groove 2210 that are connected to the ridge 30 and the bottom wall 210 are located at different length sections, so that the flow guiding direction of the connecting groove 2210 for liquid water is inclined to the bottom wall 210. When the liquid water in the connecting groove 2210 reaches the bottom wall 210, the inclined structure of the connecting groove 2210 can make the liquid water have a smaller speed in the direction perpendicular to the bottom wall 210, thereby reducing the risk of liquid water impacting the second side wall 230 and making it easier to flow into the channel on the bottom wall 210 for liquid water to circulate. It should also be noted that in some embodiments of this disclosure, the end of the connecting groove 2210 connected to the bottom wall 210 is located downstream of the liquid flow direction in the flow channel 20 compared to the end of the connecting groove 2210 in contact with the ridge 30. During the process of guiding liquid water in the connecting groove 2210, when the liquid water reaches the area in contact with the bottom wall 210, the liquid water has a smaller speed in the direction perpendicular to the bottom wall 210, thereby reducing the risk of liquid water impact turbulence. At the same time, the liquid water has a certain speed in the direction along the length of the flow channel 20, so that while it can smoothly flow into the liquid water channel on the bottom wall 210, it can also be discharged from the bottom wall 210 more quickly, so as to realize that the liquid water flows more naturally in the connecting groove 2210 and the bottom wall 210, and further optimizes the guiding path of the liquid water.

[0038] It should be noted that, in the bipolar plate provided in this embodiment, such as Figure 4 As shown, the inclination angle B of the connecting groove 2210 on the first side wall 220 ranges from 0 to 90°. Here, the inclination angle specifically refers to the angle between the connecting groove 2210 and the edge of the connecting bottom wall 210 of the first side wall 220, so as to meet the flow of liquid water in the connecting groove 2210 and ensure the guiding effect of the connecting groove 2210.

[0039] Furthermore, in some embodiments of this disclosure, multiple connecting grooves 2210 are provided, and the multiple connecting grooves 2210 are arranged in parallel on the first sidewall 220. The parallel arrangement of the connecting grooves 2210 allows liquid water to pass through the first sidewall 220 in a similar flow state within each connecting groove 2210. Simultaneously, the flow rate and velocity of the liquid water in each connecting groove 2210 are similar, avoiding the accumulation of liquid in localized areas on the first sidewall 220. Furthermore, the spacing between adjacent connecting grooves 2210 is equal, specifically as follows: Figure 4As shown, the spacing L between two adjacent connecting grooves 2210 on one side edge of the first sidewall 220 is 1.5mm-2.0mm, while the depth of a single connecting groove 2210 is 0.04mm-0.06mm. On the one hand, setting the spacing of adjacent connecting grooves 2210 on one side edge of the first sidewall 220 to 1.5mm-2.0mm ensures that each connecting groove 2210 on the first sidewall 220 can guide the liquid water in an appropriate area, and the flow rate in a single connecting groove 2210 will not be too large, resulting in overflow and turbulence. On the other hand, ensuring that the depth of each connecting groove 2210 is 0.04mm-0.06mm ensures that the flow path of liquid water in the connecting groove 2210 is wide enough, avoiding the problem of blockage and convergence of liquid water in the connecting groove 2210.

[0040] Furthermore, in the bipolar plate provided in this embodiment, the first sidewall 220 is configured as an inclined structure based on the bottom wall 210, so that liquid water can be carried by the first sidewall 220 and flow smoothly along the first sidewall 220 to the position of the bottom wall 210. Specifically, as shown... Figure 3 As shown, the angle A between the first sidewall 220 and the bottom wall 210 is designed to be 100°-170°. If the angle is too large, the gravity of the liquid water will make it difficult to overcome the adhesion force between the liquid water and the first sidewall 220, thus preventing the liquid water from flowing smoothly through the first sidewall 220 and reaching the bottom wall 210. If the angle is too small, the resistance experienced by the liquid water on the first sidewall 220 will be too small, resulting in an excessively high liquid water flow rate and a risk of splashing along the first sidewall 220. Therefore, the angle between the first sidewall 220 and the bottom wall 210 is limited to 100°-170° to ensure rapid adhesion and flow of liquid water on the first sidewall 220, ensuring that the first sidewall 220 has a good guiding effect.

[0041] Furthermore, it should be noted that for the flow channel 20 of the bipolar plate, the second sidewall 230 is hydrophobic and restricts the flow space for gas. To further improve the transport effect of the flow channel 20 for gas and liquid water, in some embodiments of this disclosure, a hydrophobic area is retained on the side of the bottom wall 210 that contacts the second sidewall 230. The channel on the bottom wall 210 for liquid water flow occupies only a part of the bottom wall 210, while the other part of the bottom wall 210 is used for gas flow. Considering the flow requirements of liquid water, the width of the hydrophobic area on the bottom wall 210 is smaller than the width of the hydrophilic area on the bottom wall 210, so that the liquid water has sufficient flow space and reduces its risk of blockage. This structure allows the flow channel 20 to be used by both gas and liquid water in parallel in its width direction. Liquid water can smoothly exit the flow channel 20 through the hydrophilic area, reducing the mutual flow influence between liquid water and gas, thus enabling the bipolar plate to better adapt to different operating conditions.

[0042] It should be further explained that in the above embodiments, the bottom wall 210 is configured as a structure of splicing hydrophobic and hydrophilic regions, so that gas and liquid water can only adhere to the sidewall and flow along the length of the flow channel 20. In other embodiments of this disclosure, the bottom wall 210 can also be entirely configured as a hydrophilic region, so that liquid water can cover the entire area of ​​the bottom wall 210 and flow along the length of the flow channel 20, while the gas is located on top of the liquid water in a direction perpendicular to the bottom wall 210 and adheres to the second sidewall 230 to achieve flow.

[0043] Furthermore, in the bipolar plate with a gas-water separation internal flow channel provided in this embodiment, the hydrophilic regions on the ridge 30 and the first sidewall 220 can be modified by laser engraving, coating, or chemical etching to effectively achieve surface hydrophilization and ensure surface uniformity and stability. Specifically, laser engraving is a high-precision surface treatment method that can precisely form tiny textures or patterns on the ridge 30 and the first sidewall 220, thereby increasing the surface hydrophilicity; the coating method achieves surface hydrophilization by coating a layer of hydrophilic material on the surface, and can precisely control the surface hydrophilicity by adjusting the thickness and composition of the coating; while the chemical etching method changes the chemical properties of the surface through a chemical reaction, making it hydrophilic. Different modification methods can be selected according to different needs in actual working conditions.

[0044] In some embodiments of this disclosure, the bottom wall 210 is treated with laser engraving to create a hydrophilic environment. Simultaneously, the laser trajectory during the laser engraving process is in the same direction as the liquid water flow within the channel 20. This allows the hydrophilic area treated by the laser trajectory to have a certain tilting guiding effect on the liquid water during the flow of liquid water. The liquid water can flow more naturally along the hydrophilic area, reducing the residence time of the liquid water within the channel 20 and improving the discharge efficiency of the liquid water.

[0045] Furthermore, in the bipolar plate provided in this embodiment, the cross-section of the flow channel 20 along its length can be trapezoidal, rectangular, or arc-shaped, all of which can form a sufficiently wide flow channel 20 to reduce the retention of liquid water within the flow channel 20, and have a continuous wall structure to reduce eddies in the liquid water within the flow channel 20, thereby improving the liquid discharge efficiency. It should also be noted that the cross-sectional dimensions of the flow channel 20 along its length can be the same or different; only the flow channel 20 structure needs to be formed.

[0046] This disclosure also provides a fuel cell, which includes a membrane electrode assembly (MEA) and a bipolar plate with a gas-water separation internal flow channel as provided in any of the above embodiments. The bipolar plate is disposed on both sides of the MEA, and the connecting side 10 of the bipolar plate faces the gas diffusion layer on the MEA. It should be noted that since this bipolar plate has the technical effects provided in any of the above embodiments, the fuel cell also has the technical effects provided in any of the above embodiments, and will not be elaborated further here.

[0047] The terms "first," "second," "left side," and "right side," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish different objects, not to describe a specific order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units may not be defined in the listed steps or units, but may include steps or units not listed.

[0048] The above description of the disclosed embodiments enables those skilled in the art to make or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A bipolar plate having a gas-water separation inner cavity flow channel, characterized by, The application relates to a bipolar plate with gas-water separation inner cavity flow channels. The connecting side (10) comprises a plurality of groups of flow channels (20) arranged in recesses and ridges (30) separating adjacent two flow channels (20); a single flow channel (20) comprises a bottom wall (210) and first and second side walls (220 and 230) arranged on opposite sides of the bottom wall (210) and respectively communicating with a ridge (30); the ridges (30) and the bottom wall (210) are modified into hydrophilic surfaces, at least part of the first side wall (220) is modified into a hydrophilic region, and the hydrophilic region of the first side wall (220) communicates with the bottom wall (210) and a ridge (30); other regions of the flow channel (20) are hydrophobic surfaces. The first side wall (220) is provided with a plurality of connecting grooves (2210), and two ends of a single connecting groove (2210) are connected to the bottom wall (210) and the ridge (30) respectively; the inner wall of the connecting groove (2210) is hydrophilic, and other regions of the first side wall (220) except the connecting grooves (2210) are hydrophobic surfaces.

2. The bipolar plate having a gas-water separation inner cavity flow channel according to claim 1, wherein The connecting groove (2210) has an inclination of 0-90 degrees on the first side wall (220) in the length direction of the flow channel (20), and one end of the connecting groove (2210) connected to the bottom wall (210) is located downstream of the liquid flow direction in the flow channel (20) compared with the other end connected to the ridge (30).

3. The bipolar plate having a gas-water separation inner cavity flow channel according to claim 2, wherein The plurality of connecting grooves (2210) are arranged in parallel, the interval of adjacent two connecting grooves (2210) on one side edge of the first side wall (220) is 1.5-2.0 mm, and the depth of a single connecting groove (2210) is 0.04-0.06 mm.

4. The bipolar plate having a gas-water separation inner cavity flow channel according to claim 2, wherein The included angle between the first side wall (220) and the bottom wall (210) is 100-170 degrees.

5. The bipolar plate having a gas-water separation inner cavity flow channel according to claim 1, wherein The side of the bottom wall (210) in contact with the second side wall (230) retains part of a hydrophobic region, and the width of the hydrophobic region on the bottom wall (210) is smaller than that of the hydrophilic region.

6. The bipolar plate having a gas-water separation inner cavity flow channel according to claim 1, wherein The hydrophilic regions on the ridges (30) and the first side wall (220) are modified by laser engraving, coating or chemical etching.

7. The bipolar plate having a gas-water separation inner cavity flow channel according to claim 1, wherein The bottom wall (210) is hydrophilically treated by laser engraving, and the laser track in the laser engraving process is the same as the liquid flow direction in the flow channel (20).

8. The bipolar plate having a gas-water separation inner cavity flow channel according to claim 1, wherein The cross section of the flow channel (20) in the length direction is trapezoidal, rectangular or arc-shaped, and the cross section sizes of the flow channel (20) in the length direction are the same or different.

9. The bipolar plate having a gas-water separation inner cavity flow channel according to claim 1, wherein The bipolar plate with gas-water separation inner cavity flow channels comprises a membrane electrode and the bipolar plate according to any one of claims 1-9.

10. A fuel cell characterized by comprising: ​

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