Bipolar plate for fuel cell, manufacturing method, and fuel cell

Abstract

A bipolar plate for a fuel cell, comprising an anode plate and a cathode plate. The anode plate and the cathode plate each is provided with a main extension plane and a plurality of groove parts recessed relative to the main extension plane in a flow field region of the bipolar plate. The groove parts are oriented in the longitudinal direction of the bipolar plate and are arranged side by side and spaced apart in the transverse direction. The groove parts of the anode plate and the groove parts of the cathode plate are arranged opposite to each other and the recessed directions are oriented opposite to each other, so that a coolant flow channel is jointly formed by the groove parts of the anode plate and the cathode plate, wherein a first joint portion is provided between every two adjacent groove parts of the anode plate, and a second joint portion is provided between every two adjacent groove parts of the cathode plate, and the first joint portion and the second joint portion abut against each other and are fastened to each other in a shape-fit mode. Also provided are a corresponding manufacturing method and a fuel cell. A welding process can be at least simplified or even omitted while ensuring a fixed connection between the anode plate and the cathode plate.

Description

Bipolar plate for fuel cell, manufacturing method and fuel cell Technical Field

[0001] The present invention relates to the field of fuel cells, and in particular to a bipolar plate for a fuel cell. The present invention also relates to a corresponding method for manufacturing the bipolar plate for a fuel cell and a corresponding fuel cell. Background Art

[0002] In recent years, with the development of society and the economy, concerns about air pollution and energy loss have grown. Fuel cells are highly efficient power generation devices that convert the chemical energy of fuel and oxidant directly into electricity through an electrochemical reaction, bypassing combustion. Because the reaction product is primarily water and virtually no harmful gases are emitted, fuel cells offer significant advantages in cleanliness and environmental friendliness, making them particularly attractive for use in the automotive sector.

[0003] In a fuel cell, a bipolar plate is provided to supply and distribute the reaction gas and coolant to the membrane electrode assembly, and the bipolar plate includes an anode plate and a cathode plate. In existing bipolar plates, a laser welding process is generally used to fix the anode plate and the cathode plate to each other. However, the welding process for the bipolar plate involves the arrangement of hundreds of welds. The welding stress generated during the welding process can cause deformation in the anode plate and the cathode plate. On the one hand, this may cause leakage of the reaction gas or coolant in the bipolar plate, and on the other hand, it seriously reduces the flatness of the bipolar plate, thereby further adversely affecting the overall assembly effect and operating performance of the fuel cell. In addition, the welds formed during the welding process are also prone to corrosion problems and cause unstable contact resistance.

[0004] Summary of the Invention

[0005] Therefore, the object of the present invention is to propose an improved bipolar plate for a fuel cell, which can at least reduce or even eliminate the welding process while ensuring a fixed connection between the anode plate and the cathode plate, thereby avoiding mechanical deformation and corrosion problems of the bipolar plate and effectively improving the assembly effect and working performance of the fuel cell.

[0006] According to a first aspect of the present invention, a bipolar plate for a fuel cell is provided, wherein the bipolar plate comprises at least an anode plate and a cathode plate, wherein the anode plate and the cathode plate respectively have a main extension plane and a plurality of groove portions recessed relative to the main extension plane in a flow field region of the bipolar plate, wherein the groove portions are oriented along the longitudinal direction of the bipolar plate and are arranged side by side and spaced apart from each other in a transverse direction perpendicular to the longitudinal direction, wherein the groove portions of the anode plate and the cathode plate are respectively arranged opposite to each other and the recessed directions are oriented opposite to each other, so that the coolant flow channel of the bipolar plate is formed by the groove portions of the anode plate and the cathode plate together, wherein

[0007] The anode plate is provided with a first joint portion between adjacent groove portions, and the cathode plate is provided with a second joint portion between adjacent groove portions. The first joint portion and the second joint portion are in contact with each other and fixed to each other in a form-locking manner.

[0008] Compared to the prior art, the bipolar plate for a fuel cell according to the present invention comprises a plurality of grooves oriented in a longitudinal direction and arranged side by side and spaced apart in a transverse direction perpendicular to the longitudinal direction. The opposing grooves of the anode and cathode plates collectively form coolant flow channels for the bipolar plate. The anode and cathode plates are each provided with a first joint and a second joint between adjacent grooves. These joints abut against each other and are secured to each other in a form-locking manner. This eliminates the need for welding, at least in the flow field region, thereby avoiding mechanical deformation of the anode and cathode plates caused by welding stress during welding and preventing corrosion and unstable contact resistance at the weld points. This simplifies the bipolar plate assembly process and improves assembly smoothness and sealing, thereby optimizing fuel cell performance.

[0009] Exemplarily, one of the first joint portion of the anode plate and the second joint portion of the cathode plate is provided with at least one protrusion, and the other is correspondingly provided with at least one recess adapted to the shape of the protrusion, and the protrusion is embedded in the recess.

[0010] Exemplarily, the convex portion and the concave portion have a square, trapezoidal or curved cross-sectional shape perpendicular to the main extension plane; and / or the convex portion is embedded in the concave portion in an interference fit manner.

[0011] Exemplarily, a conductive adhesive is applied between the first joint portion of the anode plate and the second joint portion of the cathode plate; and / or, the anode plate and the cathode plate are constructed as hydraulically formed metal sheets.

[0012] Exemplarily, the cross-sectional area of ​​the first groove portion of the anode plate is larger than the cross-sectional area of ​​the second groove portion of the cathode plate, so that the flow area of ​​the anode gas flow channel formed by the side wall of the first groove portion and the first joint portion of the anode plate is smaller than the flow area of ​​the cathode gas flow channel formed by the side wall of the second groove portion and the second joint portion of the cathode plate; alternatively, the first groove portion of the anode plate and the second groove portion of the cathode plate are symmetrically constructed.

[0013] Exemplarily, the bipolar plate has a manifold area, in which an anode gas inlet, an anode gas outlet, a cathode gas inlet, a cathode gas outlet, a coolant inlet and a coolant outlet are provided, wherein the anode gas inlet and the anode gas outlet are respectively connected to the anode gas flow channel of the flow field area, the cathode gas inlet and the cathode gas outlet are respectively connected to the cathode gas flow channel of the flow field area, and the coolant inlet and the coolant outlet are respectively connected to the coolant flow channel; and / or, a sealing bonding portion is provided at the outer periphery of the bipolar plate between the anode plate and the cathode plate.

[0014] Exemplarily, the bipolar plate is provided with additional sealing bonds around each inlet and outlet in the manifold region; and / or the area of ​​the anode gas inlet and the anode gas outlet is smaller than the area of ​​the cathode gas inlet and the cathode gas outlet.

[0015] According to a second aspect of the present invention, a method for manufacturing a bipolar plate for a fuel cell is provided, wherein the manufacturing method comprises at least the following steps:

[0016] S1: Providing an anode plate and a cathode plate, wherein the anode plate and the cathode plate respectively have a main extension plane and a plurality of groove portions recessed relative to the main extension plane in a flow field region of the bipolar plate, wherein the groove portions are oriented along a longitudinal direction of the bipolar plate and are arranged side by side and spaced apart from each other in a transverse direction perpendicular to the longitudinal direction, wherein the anode plate is provided with a first joint portion between adjacent groove portions, and the cathode plate is provided with a second joint portion between adjacent groove portions;

[0017] S2: positioning the anode plate and the cathode plate relative to each other so that the groove portions of the anode plate and the cathode plate are respectively arranged opposite to each other and the recessed directions are oriented opposite to each other;

[0018] S3: The anode plate and the cathode plate are fixedly assembled together, in that the first joint portion of the anode plate and the second joint portion of the cathode plate are respectively abutted against each other and fixed to each other in a form-fitting manner.

[0019] Exemplarily, in step S1, a conductive adhesive is applied on the first joint of the anode plate and / or the second joint of the cathode plate; and / or, one of the first joint of the anode plate and the second joint of the cathode plate is provided with at least one convex portion, and the other is correspondingly provided with at least one concave portion adapted to the shape of the convex portion, and the convex portion is embedded in the concave portion in step S3.

[0020] According to a third aspect of the present invention, there is provided a fuel cell, wherein the fuel cell comprises at least:

[0021] - a membrane electrode assembly; and

[0022] - The bipolar plates according to the present invention are arranged on both sides of the membrane electrode assembly in the thickness direction. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The present invention will be described in more detail below with reference to the accompanying drawings, so that the principles, features and advantages of the present invention can be better understood. The accompanying drawings include:

[0024] FIG1 shows a schematic cross-sectional view of a fuel cell according to an exemplary embodiment of the present invention;

[0025] FIG2 shows a schematic view of a bipolar plate for a fuel cell according to an exemplary embodiment of the present invention;

[0026] 3a and 3b are schematic cross-sectional views of bipolar plates of a fuel cell according to different exemplary embodiments of the present invention;

[0027] FIG4 shows a schematic flow chart of a method for manufacturing a bipolar plate for a fuel cell according to an exemplary embodiment of the present invention. DETAILED DESCRIPTION

[0028] In order to make the technical problems, technical solutions and beneficial technical effects to be solved by the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and a number of exemplary embodiments. It should be understood that the specific embodiments described herein are only used to illustrate the present invention and are not intended to limit the scope of protection of the present invention. For the sake of brevity, elements with the same reference numerals are only marked once in the drawings.

[0029] It should be understood that, in this document, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance, nor as implicitly specifying the quantity of the technical features being referenced. A feature specified as "first" or "second" may explicitly or implicitly indicate that at least one of the features is included.

[0030] In this specification, unless otherwise specified or limited, the terms "mounted," "connected," and "connected" should be interpreted broadly. For example, they can refer to fixed, removable, or integral connections; mechanical or electrical connections; direct connections, indirect connections through intermediaries, or internal communication between two components. Those skilled in the art will understand the meaning of these terms in this disclosure based on the specific circumstances.

[0031] Figure 1 shows a schematic cross-sectional view of a fuel cell 100 according to an exemplary embodiment of the present invention. Figure 2 shows a schematic view of a bipolar plate 20 for use in the fuel cell 100 according to an exemplary embodiment of the present invention. The fuel cell 100 is a proton exchange membrane fuel cell and can be used, in particular, in a vehicle.

[0032] As shown in Figure 1, the fuel cell 100 includes a membrane electrode assembly 10, which is the core component of the fuel cell 100 and is exemplarily composed of a proton exchange membrane 11 located in the middle, two catalyst layers 12 arranged on both sides of the proton exchange membrane 11, and two gas diffusion layers 13. The gas diffusion layers are arranged on the side of the catalyst layer 12 facing away from the proton exchange membrane 11, wherein the anode gas, usually hydrogen, is supplied to the anode of the membrane electrode assembly 10, reaches the catalyst layer 12 through the gas diffusion layer 13 and decomposes into hydrogen ions and releases two electrons under the catalytic action of the anode catalyst, such as platinum. The hydrogen ions pass through the proton exchange membrane 11 to reach the cathode and react with the cathode gas, such as oxygen in the air, which reaches the catalyst layer 12 through the gas diffusion layer 13 on the other side under the action of the cathode catalyst to generate water, and the released electrons form an electric current in the external circuit.

[0033] As shown in FIG1 , the fuel cell 100 includes bipolar plates 20 configured to supply reactant gases and coolant from a manifold to the membrane electrode assembly 10, discharge excess reactant gases and product water, as well as the coolant after absorbing heat, from the membrane electrode assembly 10, and collect and conduct electrical current. The bipolar plates 20 are arranged on both sides of the membrane electrode assembly 10 in the thickness direction Z, thereby clamping the membrane electrode assembly 10 between the two bipolar plates 20 to support and retain the membrane electrode assembly 10.

[0034] As shown in FIG1 , the bipolar plate 20 includes an anode plate 21 and a cathode plate 22 that are fixedly connected and opposed to each other. When the bipolar plate 20 is assembled in the fuel cell 100, the anode plate 21 faces the anode side of one membrane electrode assembly 10 and is configured to supply anode gas, such as hydrogen, from an anode gas manifold to the anode of the membrane electrode assembly 10, while the cathode plate 22 faces the cathode side of the adjacent membrane electrode assembly 10 and is configured to supply cathode gas, such as oxygen, from a cathode gas manifold to the cathode of the membrane electrode assembly 10. Furthermore, the bipolar plate 20 is configured to allow coolant from a coolant supply manifold to flow through the flow field area of ​​the fuel cell 100, thereby absorbing heat generated by the membrane electrode assembly 10 and achieving a desired cooling effect on the fuel cell 100.

[0035] As shown in Figures 1 and 2, the anode plate 21 and the cathode plate 22 each have a main extension plane and a plurality of groove portions 23 recessed relative to the main extension plane in the flow field region 31 of the bipolar plate 20. The groove portions are oriented along the longitudinal direction X of the bipolar plate 20 and are arranged side by side and spaced apart from each other in the transverse direction Y perpendicular to the longitudinal direction X. The groove portions 23 of the anode plate 21 are first groove portions 231, while the groove portions 23 of the cathode plate 22 are second groove portions 232. See Figures 3a and 3b for details. The grooves 23 of the anode plate 21 and the cathode plate 22 are arranged opposite to each other, and the recessed directions of the grooves 23 in the thickness direction Z are oriented opposite to each other. As a result, the opposing grooves 23 of the anode plate 21 and the cathode plate 22 collectively form coolant channels 24 of the bipolar plate 20. These coolant channels are configured to guide coolant through the flow field region 31 of the bipolar plate 20. This allows for a large flow area of ​​the coolant channels 24, thereby increasing the coolant flow rate and improving the heat dissipation of the bipolar plate 20. In particular, the coolant channels 24 are configured in a wavy shape along the longitudinal direction X, which can extend the coolant flow path in the flow field region 31 and further improve the heat dissipation of the bipolar plate 20. Of course, other configurations of the coolant channels 24 are also conceivable, such as straight-running configurations.

[0036] As shown in FIG1 , the anode plate 21 and the cathode plate 22 each have joints 25 between adjacent grooves 23 . These joints abut against each other and are secured to each other in a form-locked manner when the bipolar plate 20 is assembled. The anode plate 21 has a first joint 251 between adjacent first grooves 231 , and the cathode plate 22 has a second joint 252 between adjacent second grooves 232 . The first and second joints abut against each other and are secured to each other in a form-locked manner (see FIG3 a and FIG3 b for details). The form-locking fixation of the respective joints 25 can limit the freedom of movement of the anode and cathode plates 21, 22 and prevent undesirable displacement, without requiring laser welding of the anode and cathode plates 21, 22. This effectively prevents mechanical deformation of the anode and cathode plates 21, 22 due to welding stress during welding, and avoids corrosion at the welds. Furthermore, the contact resistance between the anode plate 21 and the cathode plate 22 at the joint 25 can be maintained stable, thereby improving the output performance of the fuel cell 100. As shown in FIG1 , the anode plate 21 is configured with a plurality of anode gas flow channels 26. These anode gas flow channels are formed by the sidewalls of the first groove portion 231 of the anode plate 21 and the first joint portion 251, and are configured to guide and supply anode gas to the anode-side gas diffusion layer 13. The cathode plate 22 is configured with a plurality of cathode gas flow channels 27. These cathode gas flow channels are formed by the sidewalls of the second groove portion 232 of the cathode plate 22 and the second joint portion 252, and are configured to guide and supply cathode gas to the cathode-side gas diffusion layer 13. The anode gas flow channels 26 and the cathode gas flow channels 27 are sealed and separated by the anode plate 21 and the cathode plate 22. In the transverse direction Y, the coolant flow channels 24 are arranged alternately with the gas flow channels.

[0037] 3 a and 3 b respectively illustrate schematic cross-sectional views of a bipolar plate 20 of a fuel cell 100 according to different exemplary embodiments of the present invention.

[0038] As shown in Figures 3a and 3b, the first joining portion 251 of the anode plate 21 is provided with at least one protrusion 1, while the second joining portion 252 of the cathode plate 22 is provided with at least one recess 2. The protrusion 1 is adapted in shape to the recess 2 and snaps into place within the recess 2, thereby achieving a form-locked fixation of the first and second joining portions 251, 252 and preventing undesirable relative displacement of the anode and cathode plates 21, 22. Of course, it is also possible for the recess 2 to be provided in the first joining portion 251 of the anode plate 21, and the protrusion 1 to be provided in the second joining portion 252 of the cathode plate 22. Furthermore, it is also conceivable for the first joining portion 251 of the anode plate 21 to have multiple protrusions 1 or recesses 2, and for the second joining portion 252 of the cathode plate 22 to have corresponding multiple recesses 2 or protrusions 1. In this case, the protrusion 1 is snapped into place within the recess 2, particularly with an interference fit, thereby enhancing the form-locked connection strength between the first and second joining portions 251, 252.

[0039] For example, as shown in FIG3a , the protrusion 1 and recess 2 in the joint 25 of the anode plate 21 and the cathode plate 22 have a trapezoidal cross-sectional shape perpendicular to the main extension plane. It is also possible for the protrusion 1 and recess 2 to have a curved, for example sinusoidal, cross-sectional shape, as shown in FIG3b . Of course, other cross-sectional shapes that are considered meaningful by a person skilled in the art, such as a square, are also conceivable. In this case, the anode plate 21 and the cathode plate 22 can be constructed as hydroformed sheet metal parts, thereby making it easy and cost-effective to form the groove portion 23 and the protrusion 1 and recess 2 in the joint 25.

[0040] For example, a conductive adhesive is applied between the first joint 251 of the anode plate 21 and the second joint 252 of the cathode plate 22. The conductive adhesive can not only improve the connection strength between the first joint 251 and the second joint 252 to avoid relative movement of the anode plate 21 and the cathode plate 22 as much as possible, but also reduce the contact resistance between the anode plate 21 and the cathode plate 22 and enhance the conductivity, thereby improving the working performance of the fuel cell 100.

[0041] For example, as shown in Figures 3a and 3b, the cross-sectional area of ​​the first groove portion 231 of the anode plate 21 is larger than the cross-sectional area of ​​the second groove portion 232 of the cathode plate 22. This results in the flow area of ​​the anode gas flow channel 26 formed by the sidewalls of the first groove portion 231 and the first joint portion 251 of the anode plate 21 being smaller than the flow area of ​​the cathode gas flow channel 27 formed by the sidewalls of the second groove portion 232 and the second joint portion 252 of the cathode plate 22. In this case, a larger flow rate of cathode gas, such as air, is allowed to flow through the cathode gas flow channel 27 than through the anode gas flow channel 26. This allows sufficient oxygen in the air to be supplied to the membrane electrode assembly 10, thereby ensuring the output efficiency of the fuel cell 100. Of course, it is also conceivable that the groove portions 23 of the anode plate 21 and the cathode plate 22 are symmetrically configured, as shown in Figure 1.

[0042] For example, as shown in FIG2 , the bipolar plate 20 has a manifold region 32 , in which an anode gas inlet 321 , an anode gas outlet 322 , a cathode gas inlet 323 , a cathode gas outlet 324 , a coolant inlet 325 , and a coolant outlet 326 are provided. The anode gas inlet 321 and the anode gas outlet 322 are respectively connected to the anode gas flow channel 26 of the flow field region 31 , the cathode gas inlet 323 and the cathode gas outlet 324 are respectively connected to the cathode gas flow channel 27 of the flow field region 31 , and the coolant inlet 325 and the coolant outlet 326 are respectively connected to the coolant flow channel 24 . In particular, the bipolar plate 20 has a fluid guide region 33 between the flow field region 31 and the manifold region 32 . The fluid guide region 33 allows the reactant gas and coolant from the manifold region 32 to flow evenly into the flow field region 31 .

[0043] For example, as shown in FIG2 , the areas of the anode gas inlet 321 and the anode gas outlet 322 are smaller than the areas of the cathode gas inlet 323 and the cathode gas outlet 324 , which enables a relatively large flow of air to flow through the cathode gas inlet 323 to the cathode gas flow channel 27 of the bipolar plate 20 , thereby achieving sufficient oxygen supply.

[0044] For example, a sealing adhesive portion is provided at the outer periphery of the bipolar plate 20 between the anode plate 21 and the cathode plate 22. The sealing adhesive portion circumferentially surrounds the bipolar plate 20, thereby further ensuring the fixed connection between the anode plate 21 and the cathode plate 22 and preventing the reaction gas and coolant from the manifold area 32 from leaking to the outside. Furthermore, it is also possible that the bipolar plate 20 is provided with additional sealing adhesive portions around each manifold inlet and manifold outlet in the manifold area 32, respectively, to prevent the different supplied fluids from mixing with each other. However, it is also conceivable to provide welded portions at the outer periphery of the bipolar plate 20 and / or around each inlet and outlet of the manifold area 32.

[0045] FIG. 4 shows a schematic flow chart of a method for manufacturing a bipolar plate 20 for a fuel cell 100 according to an exemplary embodiment of the present invention.

[0046] As shown in FIG4 , the manufacturing method according to the present invention comprises at least the following steps:

[0047] S1: Providing an anode plate 21 and a cathode plate 22, wherein the anode plate 21 and the cathode plate 22 each have a main extension plane and a plurality of groove portions 23 recessed relative to the main extension plane in a flow field region 31 of the bipolar plate 20, wherein the groove portions are oriented along the longitudinal direction X of the bipolar plate 20 and are arranged side by side and spaced apart from each other in the transverse direction Y, wherein the anode plate 21 is provided with a first joint portion 251 between adjacent first groove portions 231, and the cathode plate 22 is provided with a second joint portion 252 between adjacent second groove portions 232, in particular, the first joint portion 251 and the second joint portion 252 are respectively configured as a protrusion 1 and a recess 2 adapted to the shape of the protrusion;

[0048] S2: Positioning the anode plate 21 and the cathode plate 22 relative to each other so that the groove portions 23 of the anode plate 21 and the cathode plate 22 are respectively arranged opposite to each other and their recessed directions are oriented opposite to each other, and the joint portions 25 of the anode plate 21 and the cathode plate 22 are also arranged opposite to each other, wherein, correspondingly, the first joint portion 251 of the anode plate 21 and the second joint portion 252 of the cathode plate 22 are also arranged opposite to each other;

[0049] S3: The anode plate 21 and the cathode plate 22 are fixedly assembled together in such a manner that the first joining portion 251 of the anode plate 21 and the second joining portion 252 of the cathode plate 22 are respectively abutted against each other and fixed to each other in a form-locking manner, in particular, the protrusion 1 is snapped into the recess 2.

[0050] For example, in step S1, a conductive adhesive is applied on the sides facing each other of the first joint portion 251 of the anode plate 21 and / or the second joint portion 252 of the cathode plate 22, and the conductive adhesive can enhance the connection strength between the anode plate 21 and the cathode plate 22 and reduce the contact resistance between the anode plate 21 and the cathode plate 22 in step S3.

[0051] The above explanation of the embodiments only describes the present invention within the framework of the examples. Of course, the individual features of the embodiments can be freely combined with one another as long as it makes technical sense, without departing from the framework of the present invention.

[0052] Other advantages and alternative embodiments of the present invention will be readily apparent to those skilled in the art. Therefore, the present invention, in its broader sense, is not limited to the specific details, representative configurations, and exemplary embodiments shown and described. Rather, various modifications and substitutions may be made by those skilled in the art without departing from the basic spirit and scope of the present invention.

Claims

1. A bipolar plate (20) for a fuel cell (100), characterized in that: The bipolar plate (20) comprises at least an anode plate (21) and a cathode plate (22), wherein the anode plate and the cathode plate respectively have a main extension plane and a plurality of groove portions (23) recessed relative to the main extension plane in a flow field region (31) of the bipolar plate (20), wherein the groove portions are oriented along a longitudinal direction (X) of the bipolar plate (20) and are arranged side by side and spaced apart from each other in a transverse direction (Y) perpendicular to the longitudinal direction (X), wherein the groove portions (23) of the anode plate (21) and the cathode plate (22) are respectively arranged opposite to each other and the recessed directions are oriented opposite to each other, so that the groove portions (23) of the anode plate (21) and the cathode plate (22) jointly form a coolant flow channel (24) of the bipolar plate (20), wherein: The anode plate (21) is provided with a first joint portion (251) between adjacent groove portions (23), and the cathode plate (22) is provided with a second joint portion (252) between adjacent groove portions (23), and the first joint portion and the second joint portion are in contact with each other and fixed to each other in a shape-locking manner.

2. The bipolar plate (20) according to claim 1, characterized in that: One of the first engaging portion (251) and the second engaging portion (252) is provided with at least one convex portion (1), and the other is correspondingly provided with at least one concave portion (2) whose shape matches that of the convex portion (1), and the convex portion (1) is embedded in the concave portion (2).

3. The bipolar plate (20) according to claim 2, characterized in that: The convex portion (1) and the concave portion (2) have a square, trapezoidal or curved cross-sectional shape perpendicular to the main extension plane; and / or The convex portion (1) is embedded in the concave portion (2) in an interference fit manner.

4. The bipolar plate (20) according to any one of the preceding claims, characterized in that A conductive adhesive is applied between the first joining portion (251) and the second joining portion (252); and / or The anode plate (21) and the cathode plate (22) are designed as hydroformed sheet metal parts.

5. The bipolar plate (20) according to any one of the preceding claims, characterized in that The cross-sectional area of ​​the first groove portion (231) of the anode plate (21) is greater than the cross-sectional area of ​​the second groove portion (232) of the cathode plate (22), so that the flow area of ​​the anode gas flow channel (26) formed by the side wall of the first groove portion (231) and the first joint portion (251) is smaller than the flow area of ​​the cathode gas flow channel (27) formed by the side wall of the second groove portion (232) and the second joint portion (252); or The first groove portion (231) of the anode plate (21) and the second groove portion (232) of the cathode plate (22) are symmetrically constructed.

6. The bipolar plate (20) according to any one of the preceding claims, characterized in that The bipolar plate (20) has a manifold region (32), in which an anode gas inlet (321), an anode gas outlet (322), a cathode gas inlet (323), a cathode gas outlet (324), a coolant inlet (325) and a coolant outlet (326) are provided, wherein the anode gas inlet (321) and the anode gas outlet (322) are respectively connected to the anode gas flow channel (26) of the flow field region (31), the cathode gas inlet (323) and the cathode gas outlet (324) are respectively connected to the cathode gas flow channel (27) of the flow field region (31), and the coolant inlet (325) and the coolant outlet (326) are respectively connected to the coolant flow channel (24); and / or A sealing bonding portion is provided at the outer periphery of the bipolar plate (20) between the anode plate (21) and the cathode plate (22).

7. The bipolar plate (20) according to claim 6, characterized in that: The bipolar plate (20) is provided with additional sealing bonds around each inlet and outlet in the manifold region (32); and / or The areas of the anode gas inlet (321) and the anode gas outlet (322) are smaller than the areas of the cathode gas inlet (323) and the cathode gas outlet (324).

8. A method for manufacturing a bipolar plate for a fuel cell, characterized in that: The manufacturing method comprises at least the following steps: S1: providing an anode plate (21) and a cathode plate (22), wherein the anode plate and the cathode plate respectively have a main extension plane and a plurality of groove portions (23) recessed relative to the main extension plane in a flow field region (31) of the bipolar plate (20), wherein the groove portions are oriented along a longitudinal direction (X) of the bipolar plate (20) and are arranged side by side and spaced apart from each other in a transverse direction (Y) perpendicular to the longitudinal direction (X), wherein the anode plate (21) is provided with a first joint portion (251) between adjacent groove portions (23), and the cathode plate (22) is provided with a second joint portion (252) between adjacent groove portions (23); S2: positioning the anode plate (21) and the cathode plate (22) relative to each other so that the groove portions (23) of the anode plate (21) and the cathode plate (22) are arranged opposite to each other and the recessed directions are oriented opposite to each other; S3: The anode plate (21) and the cathode plate (22) are fixedly assembled together in such a manner that the first joint portion (251) of the anode plate (21) and the second joint portion (252) of the cathode plate (22) are in contact with each other and fixed to each other in a form-locking manner.

9. The manufacturing method according to claim 8, characterized in that: In step S1, a conductive adhesive is applied on the first joint portion (251) of the anode plate (21) and / or the second joint portion (252) of the cathode plate (22); and / or One of the first engaging portion (251) and the second engaging portion (252) is provided with at least one convex portion (1), and the other is correspondingly provided with at least one concave portion (2) whose shape matches that of the convex portion (1), and the convex portion (1) is engaged in the concave portion (2) in step S3.

10. A fuel cell (100), characterized in that: The fuel cell (100) at least comprises: - a membrane electrode assembly (10); and - The bipolar plate (20) according to any one of claims 1 to 7, which is arranged on both sides of the membrane electrode assembly (10) in the thickness direction (Z).

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