Bipolar plate and fuel cell

Abstract

This application relates to a bipolar plate and a fuel cell. The bipolar plate includes a plate body, a first protrusion on the plate body, and a second protrusion on the plate body. The second protrusion is located on one side of the first protrusion along a first direction. The second protrusion includes a plurality of protrusions periodically arranged along the longitudinal direction of the plate body, and the second protrusion and the first protrusion define a flow channel extending along the longitudinal direction of the plate body. The first direction and the longitudinal direction of the plate body intersect each other. It is understood that when the reactant gas enters the flow channel along the first direction, it will flow along the protrusions of the second protrusion. The reactant gas can be disturbed by the protrusions, causing fluctuations in the gas flow velocity and pressure. That is, the reactant gas will change from steady-state transport to turbulent transport under the action of the protrusions, thereby making the reactant gas distribution more uniform and improving the reaction efficiency of the fuel cell with this bipolar plate.

Description

Technical Field

[0001] This application relates to the field of fuel cell technology, and in particular to a bipolar plate and a fuel cell. Background Technology

[0002] A fuel cell is mainly composed of alternating layers of membrane electrode assembly (MEA) and bipolar plates. The reactant gas enters the space between the bipolar plate and the MEA from one side of the bipolar plate and flows and diffuses toward the MEA. During the process of the reactant gas flowing toward the MEA, the reactant gas undergoes a series of reactions to convert chemical energy into electrical energy.

[0003] However, traditional bipolar plates are prone to uneven distribution of reactant gases during application, which affects the flow and diffusion of reactant gases to the membrane electrode. Summary of the Invention

[0004] Therefore, it is necessary to provide a bipolar plate and fuel cell to address the problem that traditional bipolar plates easily cause uneven distribution of reactant gases during application, which affects the flow and diffusion of reactant gases to the membrane electrode.

[0005] According to one aspect of this application, a bipolar plate is provided, the bipolar plate comprising:

[0006] plate body;

[0007] The first protrusion is located on the plate.

[0008] The second protrusion is disposed on the plate and located on one side of the first protrusion along the first direction; the second protrusion includes a plurality of protrusions periodically arranged along the longitudinal direction of the plate, and the second protrusion and the first protrusion define a flow channel extending along the longitudinal direction of the plate.

[0009] The first direction and the longitudinal direction of the plate intersect each other.

[0010] The bipolar plate provided in this application has a first protrusion and a second protrusion on the plate body. The first protrusion and the second protrusion are arranged sequentially along a first direction and extend along the longitudinal direction, so that a flow channel extending along the longitudinal direction can be formed between the first protrusion and the second protrusion. The second protrusion includes a plurality of protrusions periodically arranged along the longitudinal direction of the plate body. It can be understood that when the reactant gas enters the flow channel along the first direction, it will flow along the protrusions of the second protrusion. The reactant gas can be disturbed by the protrusions, causing fluctuations in the gas flow velocity and pressure. That is, the reactant gas will change from steady-state transmission to turbulent transmission under the action of the protrusions, thereby making the reactant gas distribution more uniform and improving the reaction efficiency of the fuel cell with this bipolar plate.

[0011] In one embodiment, the protrusion is configured as an arc-shaped structure.

[0012] In one embodiment, a recess is provided between two adjacent protrusions. The recess has the same structure as the adjacent protrusion and is recessed in a direction opposite to the protrusion direction of the protrusion.

[0013] In one embodiment, the first protrusion has a drainage plane facing the second protrusion;

[0014] Multiple protrusions and multiple depressions are connected to form a first arc surface, and the flow channel is defined by the flow plane and the first arc surface.

[0015] In one embodiment, the protrusion extends longitudinally along a first direction toward the side closer to the first protrusion, and the recess is formed along the first direction toward the side away from the first protrusion.

[0016] The flow-guiding plane and the first arc surface are spaced apart along the first direction, and the flow channel is formed between the flow-guiding plane and the first arc surface.

[0017] In one embodiment, the second protrusion has a second arc surface on the side opposite to the first arc surface, and the second arc surface and the plate body also define another flow channel.

[0018] In one embodiment, a first arc surface is formed on the side of the first protrusion away from the plate and adjacent to the drainage plane along a first direction to define a flow channel with the drainage plane.

[0019] In one embodiment, the plate body is provided with a plurality of first protrusions and a plurality of second protrusions, and the first protrusions and second protrusions are alternately arranged along a first direction;

[0020] Each first protrusion and the adjacent second protrusion define the flow channel.

[0021] In one embodiment, along the direction from the first protrusion toward the plate body, the top of the second protrusion is closer to the plate body than the top of the first protrusion.

[0022] According to another aspect of this application, a fuel cell is provided, including the bipolar plates described above. Attached Figure Description

[0023] Figure 1 This is a structural schematic diagram of a bipolar plate assembly according to this application;

[0024] Figure 2 This is a schematic diagram of the structure of a bipolar plate assembly combined with each other according to this application;

[0025] Figure 3 This is a front view of a bipolar plate assembly according to an embodiment of this application;

[0026] Figure 4 This is a schematic diagram of the structure of a bipolar plate assembly according to an embodiment of this application;

[0027] Figure 5 This is a schematic diagram of the structure of a bipolar plate assembly according to another embodiment of this application.

[0028] Explanation of reference numerals in the attached figures:

[0029] Bipolar plate 100;

[0030] First protrusion 1; Drainage plane 11;

[0031] Second protrusion 2; protrusion 21; recess 22; first arc surface 23; second arc surface 24;

[0032] Plate 3; First direction F1. Detailed Implementation

[0033] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0034] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0035] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0036] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0037] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0038] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0039] A fuel cell consists of a membrane electrode assembly (MEA) and bipolar plates. The flow channel structure of the bipolar plates is very important. It provides a flow channel for the reactant gases, prevents hydrogen and oxygen from mixing in the fuel cell chamber, establishes a current path between the series-connected anode and cathode, separates the fuel and oxidant, prevents the reactant gases from permeating, evenly distributes the reactant gases to the reaction layer of the electrodes for electrode reactions, and dissipates heat to maintain a uniform temperature field in the cell. Given these many functions, different structural configurations of the bipolar plates can determine the power and lifespan of the fuel cell.

[0040] The flow channels in related technologies have several problems, such as low flow channel pressure drop, which can easily cause fuel cells to "suffocate and die," or increased flow channel pressure drop, which can easily cause water to accumulate at the bends of the flow channel, resulting in ice formation at the bends during low-temperature startup and weak low-temperature startup capability. In particular, traditional bipolar plates are prone to uneven distribution of reactant gases during application, which affects the flow and diffusion of reactant gases to the membrane electrode assembly and hinders the reaction of reactant gases in the fuel cell.

[0041] Figure 1 This is a structural schematic diagram of a bipolar plate 100 assembly according to this application.

[0042] See Figure 1 This application addresses the problem of uneven distribution of reactant gases when they are transported to the membrane electrode via the bipolar plate 100 by providing a bipolar plate 100. The bipolar plate 100 includes a plate body 3, a first protrusion 1 disposed on the plate body 3, and a second protrusion 2 disposed on the plate body 3. The second protrusion 2 is located on one side of the first protrusion 1 along the first direction F1. That is, the first protrusion 1 and the second protrusion 2 are arranged sequentially along the first direction F1.

[0043] The second protrusion 2 includes a plurality of protrusions 21 periodically arranged along the longitudinal direction of the plate 3, and the second protrusion 2 and the first protrusion 1 define a flow channel extending along the longitudinal direction of the plate 3, wherein the first direction F1 and the longitudinal direction of the plate 3 intersect each other. It can be understood that, since the second protrusion 2 includes protrusions 21 arranged along the longitudinal direction of the plate 3, when the reactant gas enters the flow channel along the first direction, the airflow inside the reactant gas can be disturbed by the protrusions when passing through the flow channel with the protrusions, and the speed and pressure of the airflow fluctuate. That is, the reactant gas will change from steady-state transmission to turbulent transmission under the action of the protrusions, thereby making the reactant gas distribution more uniform, which is beneficial to improving the reaction efficiency of the fuel cell.

[0044] See Figure 1 The protrusion 21 is constructed as an arc shape. The arc shape of the protrusion 21 can prevent the reactant gas from flowing along the arc shape of the protrusion 21 towards the adjacent protrusion 21 when it flows in the flow channel, and prevent the reactant gas from accumulating on one side of the protrusion and causing flow channel blockage.

[0045] A recess 22 is provided between two adjacent protrusions 21. The recess 22 has the same structure as the adjacent protrusion 21 and is recessed in the opposite direction to the protrusion direction of the protrusion 21. That is, the protrusion 21 and the recess 22 are adjacent and identical arc-shaped structures. The arc-shaped protrusions and recesses can make the flow channel relatively smooth, guiding the reactant gas to flow along the arc-shaped protrusions and arc-shaped recesses, which can effectively avoid flow channel blockage.

[0046] The first protrusion 1 has a flow-guiding plane 11 facing the second protrusion 2. Multiple protrusions 21 and multiple recesses 22 are connected to form a first arc surface 23, which defines the flow channel. It is understood that the multiple protrusions 21 and multiple recesses 22 are arranged sequentially in an adjacent manner, and the identical arc-shaped structure of the protrusions 21 and recesses 22 allows them to form a smoothly extending first arc surface 23 when adjacent. The flow-guiding plane 11 faces the second protrusion 2, and together with the first arc surface 23 formed by the protrusions 21 and recesses 22 of the second protrusion 2, it defines the flow channel. The reactant gas is introduced into the flow channel of the bipolar plate in the longitudinal direction. When the reactant gas flow rate is high, the arrangement of multiple protrusions ensures that the reactant gas is sufficiently disturbed after entering the flow channel, resulting in a very uniform overall distribution of the reactant gas.

[0047] Continue reading Figure 1 The protrusion 21 extends longitudinally along the first direction F1 toward the side closer to the first protrusion 1, and the recess 22 is formed recessed along the first direction F1 toward the side away from the first protrusion 1. The flow-guiding plane 11 and the first arc surface 23 are spaced apart along the first direction F1, and a flow channel is formed between the flow-guiding plane 11 and the first arc surface 23. It can be understood that the protrusion 21 and the recess 22 are arranged sequentially along the longitudinal direction to form the first arc surface 23 extending along the longitudinal direction. The flow channel formed between the flow-guiding plane 11 and the first arc surface 23 also extends along the longitudinal direction so that the reactant gas can enter the flow channel from the longitudinal direction.

[0048] Figure 2 This is a schematic diagram of the structure of a bipolar plate 100 assembly combined with each other according to this application.

[0049] Combination Figure 2 As shown, a second arc surface 24 is provided on the side of the second protrusion 2 facing away from the first arc surface 23. The second arc surface 24 and the plate 3 also define another flow channel. The defined other flow channel is distributed at intervals along the first direction F1 with the flow channel defined by the first arc surface 23 and the flow guiding plane 11, and is separated by the second protrusion 2. It can be understood that by arranging multiple first protrusions 1 and first arc surfaces 23 sequentially on the plate 3 along the first direction F1, multiple flow channels can be formed between adjacent first protrusions 1 and second protrusions 2 on the plate 3, thereby constituting the entire bipolar plate 100 structure.

[0050] In this embodiment, the height of the first protrusion 1 along its direction toward the plate 3 is 1 mm, the width of the plate 3 defined between two adjacent first protrusions 1 along the first direction F1 is 1.5 mm, the height of the second protrusion 2 along the direction of the first protrusion 1 toward the plate 3 is 0.2 mm, and the width of the second protrusion 2 along the first direction F1 is 0.3 mm. The second protrusion 2 is provided on the plate 3 by pressing, and the length of both the first protrusion 1 and the second protrusion 2 along the longitudinal direction is 300 mm. Therefore, the longitudinal length of the flow channel formed by the first protrusion 1 and the second protrusion 2 in the longitudinal direction is 300 mm. When the reactive gas passes through the flow channel formed by the first protrusion 1 and the second protrusion 2, the protrusion of the second protrusion 2 can make the reactive gas diffuse more evenly, and the setting that the height of the second protrusion 2 in the direction of the first protrusion 1 toward the plate 3 is lower than the height of the first protrusion 1 along its direction toward the plate 3 makes it less likely for the reactive gas to be blocked during flow.

[0051] In this embodiment, the first arc surface 23 formed by the protrusion 21 and the recess 22 of the second protrusion 2 can be a sine curve or a cosine curve extending 0.2 mm from the first protrusion 1 toward the plate 3, wherein the period of the sine curve or cosine curve is 2π. The first arc surface 23 is set as a sine or cosine arc structure so that the first arc surface 23 is smooth enough that it is not easy for water generated during the flow of reactive gas to condense and be stored in the recess 22, thereby avoiding blockage of the flow channel.

[0052] Figure 3 This is a side view of a bipolar plate 100 assembly according to an embodiment of this application. Figure 4 This is a schematic diagram of the structure of a bipolar plate 100 assembly according to an embodiment of this application.

[0053] See Figure 3 and Figure 4 In some embodiments, the second protrusion 2 is disposed on the flow-guiding plane 11 of the first protrusion 1 along the longitudinal direction, the first arc surface 23 faces the plate 3 and forms a flow channel with the plate 3, and the protrusion 21 faces the plate 3. Specifically, one side of the formed flow channel has a plurality of protrusions 21 and recesses 22 arranged sequentially along the first direction F1. It can be understood that when the reactant gas enters the flow channel along the longitudinal direction, the airflow inside the reactant gas can be disturbed by the protrusion 21, and the speed and pressure of the airflow will fluctuate. That is, the reactant gas will change from steady-state transmission to turbulent transmission under the action of the protrusion 21, thereby making the reactant gas distribution more uniform.

[0054] It is understandable that placing the second protrusion 2 on the drainage plane can also prevent water formed during the flow of reactive gas from accumulating in the recessed part, thus avoiding blockage of the flow channel. Specifically, in this embodiment, the first arc surface 23 formed by the protrusion 21 and the recessed part 22 faces the plate body. The water formed will detach from the first arc surface under the action of gravity, so it will not cause accumulation and blockage in the recessed part.

[0055] Continue reading Figure 4 Two first protrusions 1 extending along the longitudinal direction are arranged adjacently along the first direction F1. A corresponding flow channel extending along the first direction F1 can be formed between two adjacent first protrusions 1. It can be understood that multiple first protrusions 1 are arranged at intervals along the first direction F1 on the plate 3. Multiple flow channels will be formed between two adjacent first protrusions 1 on the plate 3. A second protrusion 2 is also provided on the flow-guiding plane 11 of the first protrusion 1 on the corresponding flow channel, thereby constituting the entire bipolar plate 100 structure.

[0056] In this embodiment, the height of the first protrusion 1 along its direction toward the plate 3 can be 1 mm, the width of the plate 3 defined between two adjacent first protrusions 1 along the first direction F1 can be 1.5 mm, the height of the second protrusion 2 on the drainage plane 11 of the first protrusion 1 along the first direction F1 can be 0.15 mm, the width of the second protrusion 2 along the direction of the first protrusion 1 toward the plate 3 can be 0.25 mm, and the length of the first protrusion 1 and the second protrusion 2 in the longitudinal direction is 300 mm. Therefore, the longitudinal length of the flow channel formed by the first protrusion 1 and the second protrusion 2 in the longitudinal direction is 300 mm. The second protrusion 2 can be attached to the drainage plane 11 by adhesive bonding. When the reactive gas passes through the flow channel formed by the first protrusion 1 and the second protrusion 2, the protrusion of the second protrusion 2 allows for more uniform diffusion of the reactive gas, while the fact that the height of the second protrusion 2 in the first direction F1 is lower than the width of the plate 3 defined between two adjacent first protrusions 1 makes it less prone to blockage during gas flow.

[0057] In this embodiment, the first arc surface 23 formed by the protrusion 21 and the recess 22 of the second protrusion 2 can be an arc surface formed by extending a sine curve or a cosine curve 0.15mm in the first direction F1, wherein the period of the sine curve or cosine curve is 2π.

[0058] Figure 5 This is a schematic diagram of the structure of a bipolar plate 100 assembly according to another embodiment of this application.

[0059] See Figure 5In some embodiments, the first arc surface 23 is formed on the side of the first protrusion 1 facing away from the plate 3 and is adjacent to the drainage plane 11 along the first direction F1 to define a flow channel with the drainage plane 11. The first arc surface 23 is adjacent to the drainage plane 11 of the first protrusion 1 in the direction facing away from the plate 3. It can be understood that multiple first protrusions 1 and second protrusions 2 can be sequentially arranged on the plate 3 along the first direction F1. Then, multiple first protrusions 1 adjacent along the first direction F1 and multiple first arc surfaces 23 adjacent along the first direction F1 can define multiple flow channels extending in the longitudinal direction, thereby constituting the entire bipolar plate 100 structure.

[0060] In this embodiment, along the direction from the first protrusion 1 to the plate 3, the height of the first protrusion 1 can be 1mm, the width of the second protrusion 2 along the first direction F1 can be 1.5mm, and the length of the first protrusion 1 and the second protrusion 2 in the longitudinal direction is 300mm. Therefore, the longitudinal length of the flow channel formed by the first protrusion 1 and the second protrusion 2 in the longitudinal direction is 300mm. The second protrusion 2 can be pressed against the flow-guiding plane 11, and a pressing machine can be used to tightly connect the second protrusion 2 and the flow-guiding plane using high temperature and high pressure. When the reactive gas passes through the flow channel formed by the first protrusion 1 and the first arc surface 23, the protrusion 21 of the first arc surface 23 can make the reactive gas diffusion more uniform, while the fact that the first protrusion 1 is 1mm higher than the second protrusion 2 in its direction towards the plate 3 makes it less prone to blockage during the flow of reactive gas.

[0061] In this embodiment, the first arc surface 23 formed by the protrusion 21 and the recess 22 of the second protrusion 2 can be an arc surface formed by extending 1.5mm from the first protrusion 1 toward the plate 3 using a sine curve or a cosine curve, wherein the period of the sine curve or cosine curve is 2π.

[0062] Combination Figure 2 and Figure 4 As shown, the plate 3 is provided with multiple first protrusions 1 and multiple second protrusions 2. The first protrusions 1 and the second protrusions 2 are arranged alternately along the first direction F1. Each first protrusion 1 and the adjacent second protrusion 2 defines a flow channel. The multiple first protrusions 1 and the multiple second protrusions 2 are arranged sequentially along the first direction F1, so multiple flow channels can be defined between multiple adjacent first protrusions 1 and second protrusions 2. The multiple first protrusions 1, the multiple second protrusions 2 and the plate 3 form the entire bipolar plate 100 structure.

[0063] See Figure 1-5As shown, along the direction from the first protrusion 1 to the plate 3, the top of the second protrusion 2 is closer to the plate 3 than the top of the first protrusion 1. This arrangement allows for better flow of the reactant gas through the channel formed between the first protrusion 1 and the second protrusion 2. It is understood that if the top of the second protrusion 2 were flush with the top of the first protrusion 1, the flow of the high-velocity reactant gas into the channel would easily cause blockage. By positioning the top of the second protrusion 2 closer to the plate 3 than the top of the first protrusion 1, the protrusion 21 of the second protrusion 2 can both disrupt the flow of the reactant gas and provide sufficient space, preventing blockage and thus improving the reaction efficiency of the fuel cell equipped with the bipolar plate 100.

[0064] In some embodiments, the height of the first protrusion 1 along the direction toward the plate 3 can be set to 0.3-1.5 mm, and the width of the first protrusion 1 along the first direction F1 can be set to 0.5-1.5 mm, such as... Figure 2 As shown, the width of the plate 3 between two adjacent first protrusions 1 along the first direction F1 can be set to 0.5-1.5mm. While the height of the second protrusion 2 along the direction of the first protrusion 1 toward the plate 3 is lower than the height of the first protrusion 1 along its direction toward the body, the height of the second protrusion 2 can be set to 0.01-0.5mm.

[0065] In some embodiments, the second protrusion 2 can be disposed on the plate 3 or the drainage plane 11 of the first protrusion 1 by means of pressing, laser welding or bonding.

[0066] In some embodiments, the first protrusion 1 and the plate 3 can be an integral part. The integral part arrangement facilitates the second protrusion 2 to be disposed on the drainage surface of the plate 3 or the first protrusion 1, which simplifies the production process.

[0067] In some embodiments, the bipolar plate 100 may be a metal bipolar plate, a graphite bipolar plate, or a composite material bipolar plate.

[0068] The bipolar plate 100 structure of this application provides the following beneficial effects: On the one hand, the reactant gas enters the flow channel along the first direction and flows along the protrusion of the second protrusion. The reactant gas can be disturbed by the protrusion, causing fluctuations in the gas flow velocity and pressure. That is, the reactant gas will change from steady-state transmission to turbulent transmission under the action of the protrusion, thereby making the reactant gas distribution more uniform and improving the reaction efficiency of the fuel cell with this bipolar plate. On the other hand, the setting that the height of the second protrusion 2 along the direction of the first protrusion 1 toward the plate body 3 is lower than the height of the first protrusion 1 along its direction toward the plate body 3 ensures that the protrusion 21 will not block the flow of reactant gas during the process of disturbing the internal airflow of reactant gas.

[0069] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0070] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A bipolar plate, characterized in that, The bipolar plate includes: plate body; A first protrusion is provided on the plate; A second protrusion is disposed on the plate and located on one side of the first protrusion along a first direction; the second protrusion includes a plurality of protrusions periodically arranged along the longitudinal direction of the plate, and the second protrusion and the first protrusion define a flow channel extending along the longitudinal direction of the plate; a recess is provided between two adjacent protrusions, and the first protrusion has a drainage plane facing the second protrusion; the plurality of protrusions and the plurality of recesses are connected to form a first arc surface, and the drainage plane and the first arc surface define the flow channel; a second arc surface is provided on the side of the second protrusion away from the first arc surface, and the second arc surface and the plate further define another flow channel; the height of the second protrusion in the first direction is lower than the width of the plate defined between two adjacent first protrusions; or, the height of the second protrusion in the direction of the first protrusion toward the plate is lower than the height of the first protrusion along its direction of the plate. The first direction and the longitudinal direction of the plate intersect each other.

2. The bipolar plate according to claim 1, characterized in that, The protrusion is constructed as an arc shape.

3. The bipolar plate according to claim 1, characterized in that, The recessed portion has the same structure as the adjacent protruding portion, and is recessed in a direction opposite to the protruding direction of the protruding portion.

4. The bipolar plate according to claim 1, characterized in that, The second protrusion is provided on the plate or the drainage plane of the first protrusion by means of pressing, laser welding or bonding.

5. The bipolar plate according to claim 4, characterized in that, The protrusion extends longitudinally along the first direction toward the side closer to the first protrusion, and the recess is formed along the first direction toward the side away from the first protrusion. The drainage plane and the first arc surface are spaced apart along the first direction, and the flow channel is formed between the drainage plane and the first arc surface.

6. The bipolar plate according to claim 5, characterized in that, The first arc surface is formed on the side of the first protrusion away from the plate and is adjacent to the drainage plane along the first direction to define the flow channel with the drainage plane.

7. The bipolar plate according to claim 1, characterized in that, The second protrusion is disposed on the drainage plane of the first protrusion along the longitudinal direction, the first arc surface faces the plate and forms the flow channel with the plate, and the protrusion faces the plate.

8. The bipolar plate according to any one of claims 1-7, characterized in that, The plate is provided with a plurality of first protrusions and a plurality of second protrusions, and the first protrusions and second protrusions are alternately arranged along the first direction; Each of the first protrusions and the adjacent second protrusion defines the flow channel.

9. The bipolar plate according to claim 1, characterized in that, Along the direction from the first protrusion toward the plate, the top of the second protrusion is closer to the plate than the top of the first protrusion.

10. A fuel cell, characterized in that, Includes the bipolar plate as described in any one of claims 1-9.

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