Bipolar plate for fuel cell, manufacturing method and fuel cell

Abstract

The invention relates to a bipolar plate for a fuel cell, comprising an anode plate and a cathode plate which are opposite and fixedly connected, said bipolar plate having a flow field region in which: the anode plate is provided with a plurality of anode gas flow channels which extend in the longitudinal direction and are arranged side by side and at a distance in the transverse direction; the cathode plate is provided with a plurality of cathode gas flow channels which extend in the longitudinal direction and are arranged side by side at intervals in the transverse direction, the positions of the anode gas flow channels and the cathode gas flow channels correspond to each other, and the bottoms of the anode gas flow channels and the cathode gas flow channels are in contact with each other; a plurality of coolant flow channels are arranged between the anode plate and the cathode plate, the coolant flow channels, the anode gas flow channels and the cathode gas flow channels are alternately arranged in the transverse direction, and a plurality of first welding parts located between the bottoms of the anode gas flow channels and the bottoms of the cathode gas flow channels are arranged in the flow field area. The invention also relates to a corresponding manufacturing method and a fuel cell. And the flatness can be obviously improved, and reliable connection between the anode plate and the cathode plate is ensured.

Description

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 technology, people are paying more and more attention to issues such as air pollution and energy loss. Fuel cells are highly efficient power generation devices that convert chemical energy in anode gas and cathode gas directly into electrical energy through electrochemical reactions without going through a combustion process. The reaction product is mainly water and basically no harmful gases are emitted. Therefore, fuel cells have the advantages of high energy conversion efficiency and clean and environmentally friendly.

[0003] In a fuel cell, a bipolar plate is provided to supply and distribute the reaction gas and coolant to the membrane electrode assembly. The bipolar plate is usually welded by an anode plate and a cathode plate. In existing bipolar plates, the welds generated by welding are usually distributed on the outer periphery of the bipolar plate. However, in order to reduce the weight and thickness of the fuel cell, the anode plate and the cathode plate of the bipolar plate are becoming thinner and thinner. The welding stress generated during the welding process of the bipolar plate will cause the deformation of the anode plate and the cathode plate, especially in the flow field area. 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 working performance of the fuel cell. Summary of the invention

[0004] Therefore, the object of the present invention is to provide an improved bipolar plate for a fuel cell, which can effectively avoid deformation caused by welding, thereby significantly improving the flatness and ensuring a reliable connection between the anode plate and the cathode plate, thereby improving the assembly and working performance of the bipolar plate. In addition, the object of the present invention is also to provide a corresponding manufacturing method for the bipolar plate and a corresponding fuel cell.

[0005] According to a first aspect of the present invention, there is provided a bipolar plate for a fuel cell, characterized in that the bipolar plate comprises an anode plate and a cathode plate which are fixedly connected to each other and are opposite to each other, wherein the bipolar plate has a flow field region, in which:

[0006] - the anode plate is provided with a plurality of anode gas flow channels on a first anode plate surface facing away from the cathode plate, the anode gas flow channels extending in a longitudinal direction and arranged side by side and spaced apart from each other in a transverse direction perpendicular to the longitudinal direction;

[0007] - the cathode plate is provided with a plurality of cathode gas flow channels on a first cathode plate surface facing away from the anode plate, the cathode gas flow channels extending in the longitudinal direction and arranged side by side and spaced apart from each other in the transverse direction, wherein the positions of the anode gas flow channels and the cathode gas flow channels correspond to each other so that the bottoms of the anode gas flow channels and the bottoms of the cathode gas flow channels can contact each other;

[0008] - a plurality of coolant flow channels are provided between the second anode plate surface of the anode plate facing the cathode plate and the second cathode plate surface of the cathode plate facing the anode plate, the coolant flow channels being alternately arranged with the anode gas flow channels and the cathode gas flow channels in the transverse direction, respectively;

[0009] Wherein, a plurality of first welding portions are provided in the flow field region, and the first welding portions are located between the bottom of the anode gas flow channel and the bottom of the cathode gas flow channel.

[0010] Compared with the prior art, the bipolar plate according to the present invention is provided with a plurality of first welding portions in the flow field region, and the first welding portions are located between the bottom of the anode gas flow channel and the bottom of the cathode gas flow channel. The welding stress generated when welding these first welding portions in the flow field region can be easily released, thereby avoiding deformation of the anode plate and the cathode plate due to welding stress, thereby ensuring the flatness of the bipolar plate even when the anode plate and the cathode plate have a small thickness. In addition, by providing a plurality of first welding portions in the flow field region, the fixed connection of the anode plate and the cathode plate can be reliably achieved, thereby preventing leakage of the coolant or reaction gas in the bipolar plate. This enables the bipolar plate to meet the prescribed flatness requirements and improves the assembly and working performance of the bipolar plate.

[0011] According to a second aspect of the present invention, a method for manufacturing a bipolar plate according to the present invention is provided, wherein the manufacturing method comprises at least the following steps:

[0012] S1: placing the anode plate and the cathode plate of the bipolar plate on top of each other so that the bottom of each anode gas flow channel of the anode plate and the bottom of each cathode gas flow channel of the cathode plate are in contact with each other;

[0013] S2: constructing a plurality of first welding portions in the flow field region of the bipolar plate, wherein the first welding portions are located between the bottom of the anode gas flow channel and the bottom of the cathode gas flow channel to form a fixed connection between the anode plate and the cathode plate.

[0014] According to a third aspect of the present invention, there is provided a fuel cell, the fuel cell having at least:

[0015] - a membrane electrode assembly; and

[0016] - 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

[0017] 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:

[0018] Figure 1 shows a schematic cross-sectional view of a fuel cell according to an exemplary embodiment of the present invention;

[0019] Figure 2a and Figure 2b Schematic views of an anode plate and a cathode plate of a bipolar plate according to an exemplary embodiment of the present invention are respectively shown;

[0020] Figure 3 shows a schematic view of a bipolar plate according to an exemplary embodiment of the present invention;

[0021] Figure 4 shows a partial cross-sectional view of a bipolar plate according to an exemplary embodiment of the present invention;

[0022] Figure 5 A schematic diagram showing the distribution of welding parts of a bipolar plate according to an exemplary embodiment of the present invention is shown;

[0023] Figure 6 A schematic flow chart of a method for manufacturing a bipolar plate according to an exemplary embodiment of the present invention is shown;

[0024] Figure 7a and Figure 7b The figures respectively show welding process diagrams of a method for manufacturing a bipolar plate according to an exemplary embodiment of the present invention. DETAILED DESCRIPTION

[0025] 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 multiple exemplary embodiments.

[0026] It should be understood that, in this document, the expressions "first", "second", etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance, nor should they be understood as implicitly indicating the number of technical features indicated. Features defined as "first" or "second" may explicitly or implicitly indicate that at least one of the features is included.

[0027] Figure 1 A schematic cross-sectional view of a fuel cell 100 according to an exemplary embodiment of the present invention is shown. Figure 2a and Figure 2bSchematic views of an anode plate 21 and a cathode plate 22 of a bipolar plate 20 according to an exemplary embodiment of the present invention are respectively shown. Figure 3 A schematic view of a bipolar plate 20 according to an exemplary embodiment of the present invention is shown. Figure 4 A partial cross-sectional view of a bipolar plate 10 according to an exemplary embodiment of the present invention is shown. Here, the fuel cell 100 is a proton exchange membrane fuel cell and can be used in particular in a vehicle.

[0028] like Figure 1 As shown, the fuel cell 100 includes a membrane electrode assembly 10, which is a core component of the fuel cell 100 and exemplarily consists 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, wherein the gas diffusion layer is arranged on the side of the catalyst layer 12 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 is decomposed into hydrogen ions and releases two electrons under the catalytic action of the anode catalyst, such as platinum, and then the hydrogen ions pass through the proton exchange membrane 11 to reach the cathode, and under the action of the cathode catalyst, 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 to generate water, and the released electrons form an electric current in the external circuit.

[0029] like Figure 1 As shown, the fuel cell 100 includes a bipolar plate 20, which is configured to supply the reaction gas and coolant from the manifold portion to the membrane electrode assembly 10 and discharge the excess reaction gas and product water and the coolant after absorbing heat from the membrane electrode assembly 10. Here, the bipolar plates 20 are arranged on both sides of the membrane electrode assembly 10 along the thickness direction Z, thereby clamping the membrane electrode assembly 10 between the two bipolar plates 20 to support and hold the membrane electrode assembly 10. Exemplarily, the fuel cell 100 also includes a packaging frame, which surrounds the membrane electrode assembly 10 in the circumferential direction and acts as a seal to prevent the supplied reaction gas and coolant from leaking. The packaging frame is not shown here for the sake of overview.

[0030] like Figure 1As shown, the bipolar plate 20 includes an anode plate 21 and a cathode plate 22 that are fixedly connected and opposite to each other, wherein 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. To this end, a plurality of anode gas flow channels 23 are configured in the anode plate 21, and the anode gas flow channels are configured to guide and supply the anode gas to the gas diffusion layer 13 on the anode side, while a plurality of cathode gas flow channels 24 are configured in the cathode plate 22, and the cathode gas flow channels are configured to guide and supply the cathode gas to the gas diffusion layer 13 on the cathode side. In addition, the bipolar plate 20 is also provided with a plurality of coolant channels 25, which are fluid-sealed and separated from the anode gas channel 23 and the cathode gas channel 24. The coolant from the coolant supply manifold, such as water, absorbs heat from the membrane electrode assembly 10 while flowing through the coolant channel 25, thereby achieving the desired cooling effect of the fuel cell 100.

[0031] For example, the anode plate 21 and the cathode plate 22 of the bipolar plate 20 may be constructed to be completely identical and rotationally symmetrical about a center point, which can reduce the difficulty and cost of manufacturing the bipolar plate 20 .

[0032] like Figure 2a and Figure 2b As shown, the anode plate 21 and the cathode plate 22 of the bipolar plate 20 respectively have flow field regions 26 corresponding to the gas diffusion layer 13 of the membrane electrode assembly 10 to supply the reaction gas to the gas diffusion layer 13 in a uniformly distributed manner.

[0033] like Figure 4As shown, in the flow field region 26, the anode plate 21 is provided with a plurality of anode gas flow channels 23 on a first anode plate surface 211 facing away from the cathode plate 22, the anode gas flow channels extending along the longitudinal direction X and arranged side by side and spaced apart from each other along a transverse direction Y perpendicular to the longitudinal direction X, and the cathode plate 22 is provided with a plurality of cathode gas flow channels 24 on a first cathode plate surface 221 facing away from the anode plate 21, the cathode gas flow channels extending along the longitudinal direction X and arranged side by side and spaced apart from each other along the transverse direction Y, wherein the positions of the anode gas flow channels 23 and the cathode gas flow channels 24 correspond to each other, so that the bottom of the anode gas flow channels 23 and the bottom of the cathode gas flow channels 24 can contact each other. Here, a plurality of coolant flow channels 25 are provided between a second anode plate surface 212 of the anode plate 21 facing the cathode plate 22 and a second cathode plate surface 222 of the cathode plate 22 facing the anode plate 21, the coolant flow channels are arranged alternately with the anode gas flow channels 23 and the cathode gas flow channels 24 in the transverse direction Y, respectively. In particular, the anode gas flow channel 23 and the cathode gas flow channel 24 extend in a wave-like manner in the longitudinal direction X, thereby significantly increasing the flow paths of the anode gas flow channel 23 and the cathode gas flow channel 24, thereby improving the diffusion efficiency of the anode gas and the cathode gas between the bipolar plate 20 and the gas diffusion layer 13 of the membrane electrode assembly 10.

[0034] like Figure 3 and Figure 4 As shown, a plurality of first welding portions 31 are provided in the flow field region 26, and the first welding portions are respectively located between the bottom of different anode gas flow channels 23 and the bottom of corresponding cathode gas flow channels 24, and the second anode plate surface 212 of the anode plate 21 and the second cathode plate 222 of the cathode plate 22 are fixedly connected together through the first welding portions 31. In this case, even if the anode plate 21 and the cathode plate 22 have a relatively small thickness, for example, a thickness less than 0.075 mm, the welding stress generated when welding these first welding portions 31 can be easily released, which can avoid deformation of the anode plate 21 and the cathode plate 22 caused by the welding stress, thereby ensuring the desired flatness of the bipolar plate 20 to optimize the assembly effect of the bipolar plate 20 in the fuel cell 100.

[0035] For example, Figure 3As shown, a plurality of first welding portions 31 in the flow field region 26 are evenly distributed along the longitudinal direction X and the transverse direction Y, respectively. For example, a first welding portion 31 is provided for every other anode gas flow channel 23 and cathode gas flow channel 24 in the transverse direction Y, and four aligned rows of first welding portions 31 are provided in the longitudinal direction X, and each first welding portion in each row of first welding portions 31 is aligned with each other. Of course, other numbers and distribution forms of first welding portions 31 that are considered meaningful by those skilled in the art can also be considered. In this way, it is possible to avoid providing too many welding portions while ensuring the flatness and fixed connection of the anode plate 21 and the cathode plate 22 of the bipolar plate 20, thereby maintaining the cost of the manufacturing process of the bipolar plate 20 at an acceptable level.

[0036] For example, Figure 2a , Figure 2b and Figure 3As shown, the anode plate 21 and the cathode plate 22 of the bipolar plate 20 respectively have a manifold area 27, wherein the anode plate 21 and the cathode plate 22 are respectively provided with an anode gas inlet 41, an anode gas outlet 42, a cathode gas inlet 43, a cathode gas outlet 44, a coolant inlet 45 and a coolant outlet 46 in the manifold area 27. Here, the anode gas inlet 41 is configured to receive anode gas, such as hydrogen, from an anode gas supply manifold and supply the anode gas to the anode side of the membrane electrode assembly 10, for which the anode gas inlet 41 is connected to the anode gas flow channel 23 in the flow field area 26 of the anode plate 21, and the anode gas outlet 42 is configured to discharge the remaining gas on the anode side of the membrane electrode assembly 10 to the anode gas discharge manifold, for which the anode gas outlet 42 is also connected to the anode gas flow channel 23 of the anode plate 21, wherein the anode gas inlet 41 and the anode gas outlet 42 are particularly arranged along the diagonal line of the bipolar plate 20. Here, the cathode gas inlet 43 is configured to receive cathode gas, such as air, from the cathode gas supply manifold and supply the cathode gas to the cathode side of the membrane electrode assembly 10, for which the cathode gas inlet 43 is connected to the cathode gas flow channel 24 in the flow field area 26 of the cathode plate 22, and the cathode gas outlet 44 is configured to discharge the remaining gas on the cathode side of the membrane electrode assembly 10 to the cathode gas discharge manifold, for which the cathode gas outlet 44 is also connected to the cathode gas flow channel 24 of the cathode plate 22, wherein the cathode gas inlet 43 and the cathode gas outlet 44 are arranged in particular along the other diagonal line of the bipolar plate 20. In particular, viewed along the longitudinal direction X, the anode gas inlet 41 and the cathode gas outlet 44 are arranged on the same side of the bipolar plate 20, and the anode gas outlet 42 and the cathode gas inlet 43 are arranged on the other side of the bipolar plate 20, so that the flow direction of the anode gas in the flow field area 26 is opposite to the flow direction of the cathode gas, which can effectively improve the reaction efficiency of the anode gas and the cathode gas. Of course, other arrangements that are considered meaningful by those skilled in the art can also be considered. In addition, the coolant inlet 45 and the coolant outlet 46 are respectively connected to the coolant flow channel 25 in the flow field area 26, and the coolant flow channel is located between the anode plate 21 and the cathode plate 22. However, it is also possible that the bipolar plate 20 does not have the manifold area 27, and the manifold portion provided in the packaging frame of the fuel cell 100 is directly connected to the flow field area 26 of the bipolar plate 20.

[0037] Exemplarily, the areas of the anode gas inlet 41 and the anode gas outlet 42 are smaller than the areas of the cathode gas inlet 43 and the cathode gas outlet 44, which can more easily meet the requirements for the flow rate and gas pressure of the anode gas and cathode gas of the fuel cell 100, thereby improving the working efficiency of the fuel cell 100.

[0038] Exemplarily, the manifold region 27 of the bipolar plate 20 is connected to the flow field region 26 through the fluid guide region 28, and the fluid guide region is arranged between the manifold region 27 and the flow field region 26. The fluid guide region 28 enables the reaction gas and the coolant to flow evenly into the flow field region 26. Specifically, as Figure 2a As shown, in the fluid guide area 28, the anode plate 21 is provided with a plurality of anode gas guide channels 51 on the first anode plate surface 211, wherein the anode gas guide channels 51 upstream of the flow field area 26 are configured to connect the anode gas inlet 41 and the anode gas flow channel 23, and the anode gas guide channels 51 downstream of the flow field area 26 are configured to connect the anode gas flow channel 23 and the anode gas outlet 42. Figure 2b As shown, in the fluid guiding area 28, the cathode plate 22 is provided with a plurality of cathode gas guiding channels 52 on the first cathode plate surface 221, wherein the cathode gas guiding channels 52 upstream of the flow field area 26 are configured to connect the cathode gas inlet 43 and the cathode gas flow channel 24, and the cathode gas guiding channels 52 downstream of the flow field area 26 are configured to connect the cathode gas flow channel 24 and the cathode gas outlet 44. Figure 2a and Figure 2b As shown, in the fluid guide area 28, a coolant guide channel 53 is constructed between the anode plate 21 and the cathode plate 22, and the coolant guide channel is configured to connect the coolant inlet 45 and the coolant flow channel 25 and the coolant flow channel 25 and the coolant outlet 46. Here, each area of ​​the bipolar plate 20 is schematically framed by a dotted line.

[0039] Exemplarily, a plurality of diverter columns 54 are provided in the coolant guide channel 53, wherein the diverter columns are formed by the anode plate 21 and the cathode plate 22 extending toward each other, and in particular being constructed in contact with each other. Through the diverter columns, the coolant supplied from the coolant inlet 45 can flow more evenly into each coolant flow channel 25, thereby achieving a more uniform cooling effect of the fuel cell 100.

[0040] Figure 5 FIG. 1 is a schematic diagram showing the distribution of welding parts of a bipolar plate 20 according to an exemplary embodiment of the present invention.

[0041] like Figure 5 As shown, the bipolar plate 20 is provided with a plurality of first welding portions 31 in the flow field region 26, and the first welding portions are evenly distributed along the longitudinal direction X and the transverse direction Y to ensure the fixed connection between the anode plate 21 and the cathode plate 22 in the flow field region 26 and prevent the bipolar plate 20 from being deformed unexpectedly due to welding stress.

[0042] like Figure 5As shown, the bipolar plate 20 is provided with a surrounding second welding portion 32 between the anode plate 21 and the cathode plate 22 at the outer periphery, and the second welding portion can further enhance the fixed connection between the anode plate 21 and the cathode plate 22 and prevent the reaction gas and coolant in the bipolar plate 20 from leaking to the outside, thereby ensuring the safe operation of the fuel cell 100. Here, the second welding portion 32 may have a welding longitudinal edge extending along the longitudinal direction X and a welding transverse edge extending along the transverse direction Y, and the welding longitudinal edge and the welding transverse edge may be completed in the same welding step or in different welding steps. In the framework of the present invention, the "welding longitudinal edge" should be understood as having an angle of less than 45° between its main extension direction and the longitudinal direction X, and the "welding transverse edge" should be understood as having an angle of less than 45° between its main extension direction and the transverse direction Y.

[0043] like Figure 5 As shown, the bipolar plate 20 is provided with a third weld 33 between the anode plate 21 and the cathode plate 22, which at least partially surrounds at least one opening in the manifold area 27. In particular, the third weld 33 and the second weld 32 together surround the anode gas inlet 41, the anode gas outlet 42, the cathode gas inlet 43 and the cathode gas outlet 44 in the manifold area 27. The third weld 33 can achieve a sealed isolation of the reaction gas inlet and outlet relative to the coolant inlet and outlet, thereby preventing the coolant from entering the anode gas flow channel 23 and the cathode gas flow channel 24. However, it is also conceivable that the third weld 33 itself completely surrounds each opening in the manifold area 27. Here, the third weld 33 can also have a weld longitudinal edge extending in the longitudinal direction X and a weld transverse edge extending in the transverse direction Y.

[0044] Figure 6 A schematic flow chart of a method for manufacturing a bipolar plate 20 according to an exemplary embodiment of the present invention is shown. Figure 7a and Figure 7b The figures respectively show welding process diagrams of a method for manufacturing a bipolar plate 20 according to an exemplary embodiment of the present invention.

[0045] like Figure 6 As shown, the manufacturing method for the bipolar plate 20 according to the present invention comprises at least the following steps:

[0046] S1: stacking the anode plate 21 and the cathode plate 22 of the bipolar plate 20 so that the outer edges of the anode plate 21 and the cathode plate 22 are aligned with each other and the bottom of each anode gas flow channel 23 of the anode plate 21 and the bottom of each cathode gas flow channel 24 of the cathode plate 22 are in contact with each other;

[0047] S2: A plurality of first welding portions 31 are constructed in the flow field region 26 of the bipolar plate 20, wherein the first welding portions are located between the bottom of the anode gas flow channel 23 and the bottom of the cathode gas flow channel 24 to form a fixed connection between the anode plate 21 and the cathode plate 22. Here, the first welding portions 31 in the flow field region 26 are evenly distributed in the longitudinal direction X and the transverse direction Y.

[0048] For example, Figure 7a As shown, in step S2, each first welding portion 31 is successively constructed from the center to the side in the longitudinal direction X and the transverse direction Y of the bipolar plate 20. Figure 7a The arrows and numbers in the figure represent the direction and order of the welding process. For example, firstly, the first welding portion 31 close to the center of the flow field area 26 in the longitudinal direction X is welded from the center to the side in the transverse direction Y along the arrow L1, and then the first welding portion 31 on the other side in the transverse direction Y is welded along the arrow L2 in the opposite direction, and so on, until all the first welding portions 31 in the flow field area 26. In this way, the welding stress generated during the welding process can be released in an orderly manner from the center to the side and the deformation of the bipolar plate 20 can be avoided as much as possible. Of course, other welding processes that are considered meaningful by those skilled in the art can also be considered.

[0049] For example, Figure 6 As shown, the manufacturing method according to the present invention may further include step S3: constructing a surrounding second weld 32 at the outer periphery of the bipolar plate 20 and / or constructing a third weld 33 at least partially surrounding the manifold area 27 in the bipolar plate 20, so as to further enhance the fixed connection between the anode plate 21 and the cathode plate 22 and achieve sealing of the bipolar plate 20 relative to the outside and between the various openings in the manifold area 27.

[0050] For example, Figure 6 As shown, step S3 may further include sub-steps:

[0051] S31: constructing the welding lateral edge of the second welding portion 32 and / or the third welding portion 33; and

[0052] S32 : constructing the welded longitudinal edges of the second welded portion 32 and / or the third welded portion 33 .

[0053] Specifically, Figure 7a and Figure 7bAs shown, firstly, the welding transverse sides of the second welding part 32 and the third welding part 33 are constructed along arrows L9 and L10 in the transverse direction Y, and then the welding longitudinal sides of the second welding part 32 and the third welding part 33 are welded along arrows L11 and L12 in the longitudinal direction X. Here, in particular, in step S2 and sub-step S31, the bipolar plate 20 is held by the same welding fixture to construct the welding transverse sides of the first welding part 31 and the second welding part 32 and the third welding part 33 according to a predetermined welding sequence, and then the bipolar plate 20 is removed and another welding fixture is replaced. During the replacement process, the welding stress generated in the previous welding process can be fully released, thereby avoiding the deformation of the bipolar plate 20 caused by the welding stress. In the next sub-step S32, the bipolar plate 20 is held by a new welding fixture, and the welding longitudinal sides of the second welding part 32 and the third welding part 33 are constructed according to a predetermined welding sequence, so as to achieve the desired flatness of the bipolar plate 20 while ensuring the connection strength of the bipolar plate 20. Of course, other welding sequences that are considered meaningful by those skilled in the art may also be considered, such as first performing sub-step S32 and then performing sub-step S31, or first constructing the second weld 32 in a continuous manner and then constructing the third weld 33, etc.

[0054] The above explanation of the embodiments only describes the 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 invention.

[0055] Other advantages and alternative embodiments of the present invention are obvious to those skilled in the art. Therefore, the present invention in its broader sense is not limited to the specific details, representative structures and exemplary embodiments shown and described. On the contrary, those skilled in the art can make various modifications and substitutions 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 an anode plate (21) and a cathode plate (22) which are opposite to each other and fixedly connected, wherein the bipolar plate (20) has a flow field area (26), in which: - the anode plate (21) is provided with a plurality of anode gas flow channels (23) on a first anode plate surface (211) facing away from the cathode plate (22), wherein the anode gas flow channels (23) extend along a longitudinal direction (X) and are arranged side by side and spaced apart from each other along a transverse direction (Y) perpendicular to the longitudinal direction (X); - the cathode plate (22) is provided with a plurality of cathode gas flow channels (24) on a first cathode plate surface (221) facing away from the anode plate (21), the cathode gas flow channels (24) extending along the longitudinal direction (X) and arranged side by side and spaced apart from each other along the transverse direction (Y), wherein the positions of the anode gas flow channels (23) and the cathode gas flow channels (24) correspond to each other, so that the bottom of the anode gas flow channels (23) and the bottom of the cathode gas flow channels (24) can contact each other; - a plurality of coolant flow channels (25) are provided between a second anode plate surface (212) of the anode plate (21) facing the cathode plate (22) and a second cathode plate surface (222) of the cathode plate (22) facing the anode plate (21), wherein the coolant flow channels (25) are arranged alternately with the anode gas flow channels (23) and the cathode gas flow channels (24) in the transverse direction (Y), A plurality of first welding portions (31) are provided in the flow field region (26), and the first welding portions are located between the bottom of the anode gas flow channel (23) and the bottom of the cathode gas flow channel (24).

2. The bipolar plate (20) according to claim 1, characterized in that: The first welding portions (31) are evenly distributed in the flow field region (26) along the longitudinal direction (X) and / or the transverse direction (Y).

3. The bipolar plate (20) according to claim 1 or 2, characterized in that: The bipolar plate (20) has a manifold region (27), in which an anode gas inlet (41), an anode gas outlet (42), a cathode gas inlet (43), a cathode gas outlet (44), a coolant inlet (45) and a coolant outlet (46) are provided, wherein the anode gas inlet (41) and the anode gas outlet (42) are respectively connected to the anode gas flow channel (23), the cathode gas inlet (43) and the cathode gas outlet (44) are respectively connected to the cathode gas flow channel (24), and the coolant inlet (45) and the coolant outlet (46) are respectively connected to the coolant flow channel (25); and / or The bipolar plate (20) is provided with a surrounding second welding portion (32) between the anode plate (21) and the cathode plate (22) at the outer periphery.

4. The bipolar plate (20) according to claim 3, characterized in that: The bipolar plate (20) is provided with a third weld (33) between the anode plate (21) and the cathode plate (22) at least partially surrounding at least one opening in the manifold region (27); and / or The second welding portion (32) and / or the third welding portion (33) comprises a welding longitudinal edge extending along the longitudinal direction (X) and a welding transverse edge extending along the transverse direction (Y); and / or The areas of the anode gas inlet (41) and the anode gas outlet (42) are smaller than the areas of the cathode gas inlet (43) and the cathode gas outlet (44).

5. The bipolar plate (20) according to claim 3 or 4, characterized in that: The bipolar plate (20) has a fluid guiding region (28) arranged between the manifold region (27) and the flow field region (26), in which: - the anode plate (21) is provided with a plurality of anode gas guide channels (51) on the first anode plate surface (211), the anode gas guide channels being configured to connect the anode gas inlet (41) and the anode gas flow channel (23) and the anode gas flow channel (23) and the anode gas outlet (52); - the cathode plate (22) is provided with a plurality of cathode gas guide channels (52) on the first cathode plate surface (221), wherein the cathode gas guide channels are configured to connect the cathode gas inlet (43) and the cathode gas flow channel (24) and the cathode gas flow channel (24) and the cathode gas outlet (44); A coolant guide channel (53) is constructed between the anode plate (21) and the cathode plate (22), and the coolant guide channel is configured to connect the coolant inlet (45) and the coolant flow channel (25) and the coolant flow channel (25) and the coolant outlet (46).

6. The bipolar plate (20) according to claim 5, characterized in that: A plurality of dividing columns (54) are arranged in the coolant guiding channel (53), and the dividing columns are configured to protrude from the anode plate (21) and the cathode plate (22) toward each other.

7. The bipolar plate (20) according to any one of the preceding claims, characterized in that The anode plate (21) and the cathode plate (22) are constructed identically to each other; and / or The anode plate (21) and the cathode plate (22) are constructed to be rotationally symmetrical around a center; and / or The anode gas flow channel (23) and the cathode gas flow channel (24) extend in a wave-like manner in the longitudinal direction (X).

8. A method for manufacturing a bipolar plate (20) according to any one of claims 1 to 7, wherein: The manufacturing method comprises at least the following steps: S1: placing the anode plate (21) and the cathode plate (22) of the bipolar plate (20) on top of each other, so that the bottom of each anode gas flow channel (23) of the anode plate (21) and the bottom of each cathode gas flow channel (24) of the cathode plate (22) are in contact with each other; S2: constructing a plurality of first welding portions (31) in the flow field region (26) of the bipolar plate (20), wherein the first welding portions are located between the bottom of the anode gas flow channel (23) and the bottom of the cathode gas flow channel (24) to form a fixed connection between the anode plate (21) and the cathode plate (22).

9. The manufacturing method according to claim 8, characterized in that: In step S2, the first welding portions (31) are successively constructed from the center to the side in the longitudinal direction (X) and / or the transverse direction (Y) of the bipolar plate (20); and / or The manufacturing method comprises step S3: constructing a surrounding second weld (32) at the outer periphery of the bipolar plate (20) and / or constructing a third weld (33) in the bipolar plate (20) that at least partially surrounds a manifold area (27).

10. The manufacturing method according to claim 9, characterized in that: The step S3 comprises the following sub-steps: S31: constructing the welding lateral edge of the second welding portion (32) and / or the third welding portion (33); and S32: constructing the welding longitudinal edges of the second welding portion (32) and / or the third welding portion (33), In particular, in step S2 and sub-step S31, the bipolar plate (20) is held by the same welding fixture, while in sub-step S32, the bipolar plate (20) is held by another welding fixture.

11. A fuel cell (100), the fuel cell (100) comprising at least: - a membrane electrode assembly (10); and - The bipolar plate (20) according to any one of claims 1 to 8, which is arranged on both sides of the membrane electrode assembly (10) in the thickness direction (Z).

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