Laser welding method and device, metal bipolar plate, hydrogen fuel cell and vehicle

Abstract

The invention provides a laser welding method and device, a metal bipolar plate, a hydrogen fuel cell and a vehicle. The laser welding method is used for a metal bipolar plate (1) of a hydrogen fuel cell, a welding path (11) is preset on the metal bipolar plate (1), the welding path (11) comprises a welding starting point (111) and a welding end point (112), and the laser welding method comprises the following steps that S1, a laser beam (2) is applied and moved from the welding starting point (111) along the welding path (11), s2, whether the moving distance of the laser beam (2) reaches a moving distance threshold value or not is judged, and if yes, the step S3 is executed; and S3, the moving speed of the laser beam (2) is reduced, and meanwhile, the laser power of the laser beam (2) is reduced or the laser power is kept unchanged.

Description

Technical Field

[0001] The present invention relates to the field of laser welding of metal bipolar plates, and in particular to a laser welding method, a device, a metal bipolar plate, a hydrogen fuel cell and a vehicle. Background Art

[0002] Bipolar plates are an important part of hydrogen fuel cells, which can collect current and distribute gas. Bipolar plates are mainly divided into two parts, namely cathode plates and anode plates. The two are connected together by welding to form a sealed channel around and a cooling channel in the middle. The sealing of bipolar plates is very high. If the leakage is caused by poor sealing, the performance of the battery will decline or lose its function. At present, the main way to connect bipolar plates is laser welding. Laser welding mainly uses a laser beam to irradiate the metal surface, and after melting, the heat of the upper plate is quickly transferred to the lower plate to form a molten pool and solidify to form a weld. The laser welded bipolar plate is divided into three areas: hydrogen area, air area and cooling water area, and the cooling water area is the activation area.

[0003] During laser welding of the activation zone, it is easy to have poor thermal control at the end of a weld path due to the small size of the area to be welded and the high temperatures during welding. If the heat input is too high, the metal sheet can easily burn through and form a perforation. If the heat input is too low, a weak weld or an incomplete weld may result.

[0004] For this type of laser welding, all welds are required to be well formed and have small thermal deformation. However, the difficulty lies in the quality of the welds: weld penetration and welding defects, rough and unsightly weld surface, severe slag splashing, discontinuous welds; and severe welding deformation after welding, and overall bulging of the plate. Summary of the invention

[0005] According to different aspects, the present invention aims to solve or alleviate the drawbacks mentioned in the background art, in particular to avoid the risk of perforation of the metal bipolar plate due to the welding process.

[0006] In addition, the present invention is also intended to solve or alleviate other technical problems existing in the prior art.

[0007] The present invention solves the above problems by providing a laser welding method, device, metal bipolar plate, hydrogen fuel cell and vehicle. Specifically, according to one aspect of the present invention, the following are provided:

[0008] A laser welding method for a metal bipolar plate for a hydrogen fuel cell, wherein the metal bipolar plate is preset with a welding path, wherein the welding path includes a welding start point and a welding end point, wherein the laser welding method includes the following steps:

[0009] S1: Starting from the welding starting point, applying and moving the laser beam along the welding path,

[0010] S2: Determine whether the moving distance of the laser beam reaches the moving distance threshold, if so, execute step S3;

[0011] S3: reducing the moving speed of the laser beam, and at the same time reducing the laser power of the laser beam or maintaining the laser power unchanged.

[0012] According to another aspect of the present invention, the present invention provides a computer-readable storage medium, on which a computer program is stored, wherein the computer program implements any of the above-mentioned laser welding methods when executed by a processor.

[0013] According to another aspect of the present invention, there is provided a computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements any one of the above-mentioned laser welding methods when executing the computer program.

[0014] According to another aspect of the present invention, the present invention provides a laser welding device for a metal bipolar plate of a hydrogen fuel cell, wherein the metal bipolar plate is preset with a welding path, wherein the welding path includes a welding starting point and a welding end point, wherein the laser welding device is used to perform any one of the above-mentioned laser welding methods, wherein the laser welding device includes a laser and a judgment module, wherein the laser is configured to apply and move a laser beam along the welding path from the welding starting point, wherein the judgment module is configured to judge whether a moving distance of the laser beam reaches a moving distance threshold, and if so, the laser is configured to reduce a moving speed of the laser beam, and at the same time reduce a laser power of the laser beam or maintain the laser power unchanged.

[0015] According to another aspect of the present invention, the present invention provides a metal bipolar plate for a hydrogen fuel cell, wherein the metal bipolar plate is welded by any one of the above-mentioned laser welding methods.

[0016] According to another aspect of the present invention, the present invention provides a hydrogen fuel cell, wherein the hydrogen fuel cell has any one of the above-mentioned metal bipolar plates.

[0017] According to yet another aspect of the present invention, the present invention provides a vehicle, wherein the vehicle has the above-mentioned hydrogen fuel cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The above and other features of the present invention will become apparent with reference to the accompanying drawings, in which:

[0019] Figure 1A schematic diagram of a process of a laser welding method according to the present invention is shown;

[0020] Figure 2 A schematic structural diagram of a metal bipolar plate according to the present invention is shown;

[0021] Figure 3 A welding parameter curve and a welding path diagram corresponding to each other according to a laser welding method of the present invention are shown;

[0022] Figure 4 A laser power curve diagram of another laser welding method according to the present invention is shown;

[0023] Figure 5 A laser moving speed curve diagram according to another laser welding method of the present invention is shown;

[0024] Figure 6 An application example of a laser welding method according to the present invention is shown; and

[0025] Figure 7 A schematic diagram of a structural module of a laser welding device according to the present invention is shown. DETAILED DESCRIPTION

[0026] It is easy to understand that according to the technical solution of the present invention, without changing the essential spirit of the present invention, a person skilled in the art can propose a variety of interchangeable structural modes and implementation modes. Therefore, the following specific implementation modes and drawings are only exemplary descriptions of the technical solution of the present invention, and should not be regarded as the whole of the present invention or as a limitation or restriction to the technical solution of the present invention.

[0027] The directional terms such as up, down, left, right, front, back, front, back, top, bottom, etc. mentioned or may be mentioned in this specification are defined relative to the structures shown in the drawings. They are relative concepts and may change accordingly according to their different positions and different usage states. Therefore, these or other directional terms should not be interpreted as restrictive terms. In addition, the terms "first", "second", "third", etc. or similar expressions are only used for description and distinction purposes, and cannot be understood as indicating or implying the relative importance of the corresponding components.

[0028] refer to Figure 1 and Figure 2 , which respectively show a schematic diagram of a laser welding method according to the present invention, and a schematic diagram of a metal bipolar plate structure according to the present invention. Figure 1 The Y indicates that the judgment result is yes.

[0029] The laser welding method is used for a metal bipolar plate 1 of a hydrogen fuel cell. The metal bipolar plate 1 is preset with a welding path 11. The welding path 11 includes a welding start point 111 and a welding end point 112 ( Figure 3 ), wherein the laser welding method comprises the following steps:

[0030] S1: Starting from the welding starting point 111, applying and moving the laser beam 2 along the welding path 11,

[0031] S2: Determine the laser beam 2 ( Figure 6 (shown) whether the moving distance reaches the moving distance threshold, if so, execute step S3; if not, continue to execute step S1 in which the laser beam 2 is moved along the welding path 11;

[0032] S3: reducing the moving speed of the laser beam 2 and at the same time reducing the laser power of the laser beam 2 or maintaining the laser power unchanged.

[0033] First of all, it should be noted that the naming of the various method steps in this article is only for the purpose of distinction and convenience of reference, and does not necessarily mean that there is a difference in the order of sequence among these method steps (unless explicitly stated). They can adjust the implementation order according to actual conditions, or even be executed simultaneously.

[0034] Those skilled in the art will appreciate the conventional construction of metal bipolar plates, such as Figure 2 As shown, it is configured with an air channel inlet 141, a coolant channel inlet 151 and a hydrogen channel inlet 161 from top to bottom on the left side, and a corresponding hydrogen channel outlet 162, a coolant channel outlet 152 and an air channel outlet 142 are configured from top to bottom on the right side, and cooling water can be used as the coolant. It should be understood that the channels can be isolated from each other so as not to affect each other. For example, the fuel gas flow channel or the hydrogen channel is constructed on the outward side of the anode plate of the metal bipolar plate, and the oxidizing gas flow channel or the air channel is constructed on the outward side of the cathode plate of the metal bipolar plate, and the surfaces of the anode plate and the cathode plate facing each other jointly form a coolant channel 15 to achieve the above requirements. Of course, according to actual requirements and application environment, those skilled in the art can modify the structure of the metal bipolar plate. Since the specific structure of the metal bipolar plate is not the focus of this disclosure, it will not be elaborated here.

[0035] However, it is important to note that during the design of the metal bipolar plate, the welding path of the metal bipolar plate is preset to facilitate the subsequent application of laser welding. Figure 2The preset welding path of the activation area (i.e., the coolant channel area) of the metal bipolar plate and the welding path of the sealing area 13 at the outer edge of the plate are exemplarily and schematically indicated. Each welding path in the activation area is represented by 5 small arc dashed lines, and its shape is adapted to the shape of the surrounding coolant channel section, so that the welding process does not affect the coolant channel itself and can achieve a good connection effect at the same time; and the welding path of the sealing area is marked with a rectangular frame, but it should also be understood that in actual applications, the welding path marked by the rectangular frame can be continuous or interrupted in the middle. Exemplarily, combined with Figure 6 (It shows an application example of a laser welding method according to the present invention, wherein the welding direction is exemplarily from the paper surface inward) It can be seen that the welding path 11 is arranged at the groove 121 of the activation area 12 of the metal bipolar plate 1, and / or is arranged in the sealing area 13 of the metal bipolar plate 1. In particular, considering that the thickness of the groove surface is usually low, the requirements for the welding process are high, which can highlight the adaptability of the laser welding method. Of course, those skilled in the art can flexibly adjust the welding path (such as its number, shape, distribution position, size) according to actual requirements. For example, those skilled in the art can also design welding paths between different channels to more comprehensively improve the connection firmness.

[0036] In addition, it should be understood that the moving speed of the laser beam described herein or similar expressions refers to the speed at which the device (such as a laser or a laser head) used to emit the laser drives the laser beam to move, rather than the propagation speed of the laser beam in the medium. Laser welding can use a continuous laser or a pulsed laser. According to the above technical solution, by reducing the moving speed of the laser when and after reaching the moving distance, the weld width can be increased, the gap can be adapted, the heat input caused by the laser is stabilized or does not increase, perforation defects or risks are avoided, and the thermal deformation of the metal bipolar plate is reduced, thereby achieving the purpose of the present disclosure. At the same time, the laser power of the laser beam 2 can be reduced or maintained unchanged. The specific method can be determined according to actual needs or by experiment. Specific examples will also be given below. In other words, the method can achieve coordinated adjustment of power and speed to dynamically control the heat input of the weld.

[0037] Figure 3 A welding parameter curve and a welding path diagram corresponding to each other of a laser welding method according to the present invention are shown.

[0038] Combination Figure 3It can be seen that in step S3, the moving speed of the laser beam 2 and the laser power of the laser beam 2 are both reduced in a linear manner with the laser moving distance. When the laser beam 2 reaches the welding end point 112, the moving speed of the laser beam 2 is the third speed, and the laser power of the laser beam 2 is the third power. It should be understood that the linear change is relatively simple to implement, and can still achieve the expected effect, with high cost performance. In this step S3, the moving speed and power of the laser beam are reduced at the same time, so as to better balance the purpose of weld widening and anti-perforation.

[0039] Furthermore, combined with Figure 4 and Figure 5 , which respectively show a laser power curve diagram of another laser welding method according to the present invention, and a laser moving speed curve diagram of another laser welding method according to the present invention.

[0040] On the welding path 11, from the welding starting point 111 to the welding end point 112, a first section (i.e., L1 to L2, indicated in the figure), a second section (i.e., L2 to L3, indicated in the figure) and a third section (i.e., L3 to L4, indicated in the figure) which are connected in sequence are divided.

[0041] Step S1 includes the following steps:

[0042] S11: In the first section, the moving speed of the laser beam 2 is set to increase from a first speed to a second speed or to remain at the second speed, and the laser power of the laser beam 2 is set to increase from a first power to a second power or to remain at the second power,

[0043] S12: in the second section, maintaining the second speed as the moving speed of the laser beam 2, and maintaining the second power as the laser power of the laser beam 2;

[0044] The third section corresponds to the distance from the moving distance threshold to the welding end point 112, and step S3 includes the following steps:

[0045] S31: reducing the moving speed of the laser beam 2 from the second speed to a third speed, and reducing the laser power of the laser beam 2 from the second power to a third power.

[0046] It can be seen from this that Figures 3 to 5Two different specific embodiments of laser welding are given. The general idea is still to reduce the moving speed of the laser beam after the movement of the laser reaches a certain threshold. These two embodiments specifically give the way in which the laser power and laser speed change with the laser moving distance or the laser application time. For example, in step S11, the increase in the moving speed of the laser beam 2 is linear with the laser moving distance, and the increase in the laser power of the laser beam 2 is linear with the laser moving distance. Those skilled in the art can naturally determine other ways of change according to actual needs or through experiments, such as changing the linear change to a parabolic change, adjusting the value of the extreme point, adding or deleting the number of extreme points, and so on.

[0047] in, Figure 3 The dotted line and the right arrow below exemplarily represent the welding path and welding direction. Of course, as mentioned above, the welding path can take other shapes, such as arc, curve, broken line, etc., and can be continuous or have breakpoints. Therefore, in the case where the welding path is non-linear, the welding distance or the laser moving distance is the distance actually scanned by the laser or the straight line length after the welding path (for example, by calculus) is converted into a straight line, rather than simply the straight line distance between the starting point and the end point. As can be seen from the figure, L3 represents the moving distance threshold mentioned in this article. The moving distance threshold can be set to 50% to 90%, for example, 60%, of the total length of the welding path 11, so as to achieve the reduction of the laser moving speed and the adjustment of the laser power at the same time when necessary in the later stage of the welding process or at the end of the welding path. Through the various laser welding embodiments designed in this way, the laser speed at the end of the welding line, for example, is reduced, the heat input is controlled, and it is helpful to suppress defects generated during the welding process. At the same time, the overall speed of laser welding can be maintained at a high level, so that the processing efficiency can be guaranteed or improved.

[0048] Regarding the specific parameter selection of laser welding, in some embodiments of the present disclosure, the laser welding method has one or more of the following characteristics:

[0049] The first speed is 500 mm / s to 2000 mm / s, or 0 mm / s;

[0050] The first power is 300W to 350W (e.g., 330W), or 0W;

[0051] The second speed is 500 mm / s to 2000 mm / s;

[0052] The second power is 300W to 350W (e.g., 330W);

[0053] The third speed is 5 mm / s to 20 mm / s (i.e. 1% of the second speed), or 0 mm / s;

[0054] The third power is 200W to 250W (eg, 230W), or is 0W.

[0055] Those skilled in the art will naturally know that they can reasonably select and combine the above-mentioned various parameters, and can exclude obviously conflicting parameter combinations.

[0056] It should be particularly mentioned that the first speed, especially the second speed, can reach 500mm / s to 2000mm / s (can also be set to 700 to 1000mm / s). It can be seen that this method can be well applied to the application scenarios of high-speed laser welding, and can greatly improve the laser moving speed of 100mm / s in the prior art, which can greatly shorten the welding cycle of the metal bipolar plate and improve the stability of the welding process and welding effect. It should be understood that not only the maximum speed, but also the average speed or median speed of this laser welding method can reach 500mm / s to 2000mm / s as required, so it can still be a high-speed laser welding process as a whole with high efficiency. Similarly, those skilled in the art can determine or adjust the values ​​of each parameter, or increase or decrease each parameter according to actual needs, application scenarios (such as actual welding path morphology) or experiments. It can be seen that this method overcomes the risk of perforation under high-speed welding and the defects of long production cycle under low-speed welding, and can obtain stable welding effects, no perforation and short cycle, especially at high welding speeds, it has the characteristics of good forming, excellent mechanical properties and no leakage (lateral and longitudinal), solving the bottleneck problem of leakage of fuel cell bipolar plate welds at high welding speeds.

[0057] According to other aspects of the present disclosure, the present disclosure also relates to a computer-readable storage medium, on which a computer program is stored, wherein when the computer program is executed by a processor, any one of the above-mentioned laser welding methods is implemented; and relates to a computer device, which includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, any one of the above-mentioned laser welding methods is implemented.

[0058] It is understood that the computer-readable storage medium and the computer device have all the technical effects of the aforementioned laser welding method, which will not be described in detail here. The computer device may include a control device formed by various electronic devices. It is also understood by those skilled in the art that the present invention implements all or part of the processes in its laser welding method, which can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a computer-readable storage medium. When the computer program is executed by the processor, the steps of the above-mentioned various method embodiments can be implemented. Among them, the computer program includes a computer program code, and it is understood that the program code includes but is not limited to the program code for executing the above-mentioned laser welding method. For ease of explanation, only the parts related to the present invention are shown. The computer program code can be in source code form, object code form, executable file or some intermediate form, etc. The computer-readable storage medium may include: any entity or device, medium, U disk, mobile hard disk, disk, optical disk, computer memory, read-only memory, random access memory, electrical carrier signal, telecommunication signal and software distribution medium, etc. that can carry the computer program code. It should be noted that the content contained in the computer-readable storage medium can be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, computer-readable storage media do not include electrical carrier signals and telecommunication signals.

[0059] refer to Figure 7 , which shows a schematic diagram of a structural module of a laser welding device according to the present invention.

[0060] Among them, since the specific shape and connection method of each component are not the subject of the present invention, for the sake of clarity and simplicity, all these components are schematically given in the form of structural modules, and those skilled in the art can choose appropriate module shapes and connection methods, etc. under the guidance of the structural diagram. In addition, the structural diagram given is an embodiment of the present invention, and those skilled in the art can make various modifications without departing from the spirit of the present invention after referring to the diagram, and these modifications should also be within the scope of protection of the present invention.

[0061] Correspondingly, the present disclosure further provides a laser welding device 100 for a metal bipolar plate 1 for a hydrogen fuel cell, wherein the metal bipolar plate 1 is preset with a welding path 11, wherein the welding path 11 includes a welding starting point 111 and a welding end point 112, wherein the laser welding device 100 is used to perform any of the above-mentioned laser welding methods, wherein the laser welding device 100 includes a laser 101 and a judgment module 102, wherein the laser 101 is configured to be able to apply and move a laser beam 2 along the welding path 11 from the welding starting point 111, wherein the judgment module 102 is configured to judge whether the moving distance of the laser beam 2 reaches a moving distance threshold, and if so, the laser 101 reduces the moving speed of the laser beam 2, and simultaneously reduces the laser power of the laser beam 2 or maintains the laser power unchanged; and provides a metal bipolar plate 1 for a hydrogen fuel cell, wherein the metal bipolar plate 1 is welded by any of the above-mentioned laser welding methods.

[0062] Similarly, for various embodiments of the laser welding device and the metal bipolar plate and the technical effects that can be achieved, please refer to the above-mentioned laser welding method for interpretation, and no further details will be given here. However, it should be mentioned that the metal bipolar plate 1 can have one or more of the following features:

[0063] The thickness of the metal bipolar plate 1 is less than 0.1 mm (e.g. 0.075 mm);

[0064] The material of the metal bipolar plate 1 is selected from one or more of stainless steel, aluminum alloy, and titanium alloy;

[0065] The width α of the groove 121 of the activation zone 12 of the metal bipolar plate 1 is ( Figure 6 shown) is less than 2 mm (e.g. 0.3 mm).

[0066] It can be seen that the various technical solutions described in this article can be well applied to metal bipolar plates with generally thin thickness and small groove width, so that the grooves can be effectively connected, and those skilled in the art can specifically select any of the three metal materials mentioned above or a composite material composed of them, so it has strong adaptability in more stringent application occasions. It is also possible to flexibly adjust various parameters according to actual needs or experiments. Of course, the various technical solutions can also be applied to metal bipolar plates with other plate thicknesses (such as 0.3 mm) or groove sizes.

[0067] Finally, the present disclosure also provides a hydrogen fuel cell, wherein the hydrogen fuel cell has any one of the above-mentioned metal bipolar plates 1; and also provides a vehicle, wherein the vehicle has the above-mentioned hydrogen fuel cell.

[0068] Please also refer to the above text to interpret the embodiments and effects of these two topics. Among them, the vehicle may include any vehicle equipped with a hydrogen fuel cell, such as a car, a truck, a bus, an electric car, etc.

[0069] In summary, the present invention can achieve a high welding speed (500 mm / s to 2000 mm / s), and the bipolar plates are well-formed, flat, and slightly deformed after welding. In addition, the two bipolar plates are firmly connected without perforation after welding, thereby avoiding leakage of the bipolar plates and improving welding efficiency.

[0070] It should be understood that all the above preferred embodiments are illustrative rather than restrictive, and various modifications or variations made by those skilled in the art to the specific embodiments described above under the concept of the present invention should be within the legal protection scope of the present invention.

Claims

1. A laser welding method for a metal bipolar plate (1) for a hydrogen fuel cell, wherein the metal bipolar plate (1) is preset with a welding path (11), wherein the welding path (11) includes a welding start point (111) and a welding end point (112), wherein: The laser welding method comprises the following steps: S1: starting from the welding starting point (111), applying and moving the laser beam (2) along the welding path (11), S2: determining whether the moving distance of the laser beam (2) reaches a moving distance threshold, and if so, executing step S3; S3: reducing the moving speed of the laser beam (2) and at the same time reducing the laser power of the laser beam (2) or maintaining the laser power unchanged.

2. The laser welding method according to claim 1, characterized in that: In step S3, the moving speed of the laser beam (2) and the laser power of the laser beam (2) are both reduced in a linear manner with the laser moving distance. When the laser beam (2) reaches the welding end point (112), the moving speed of the laser beam (2) is the third speed, and the laser power of the laser beam (2) is the third power.

3. The laser welding method according to claim 1 or 2, characterized in that: On the welding path (11), from the welding starting point (111) to the welding end point (112), a first section, a second section and a third section which are connected in sequence are divided; Step S1 includes the following steps: S11: In the first section, the moving speed of the laser beam (2) is set to increase from a first speed to a second speed or to remain at the second speed, and the laser power of the laser beam (2) is set to increase from a first power to a second power or to remain at the second power, S12: in the second section, maintaining the second speed as the moving speed of the laser beam (2), and maintaining the second power as the laser power of the laser beam (2); The third section corresponds to from the moving distance threshold to the welding end point (112), and step S3 includes the following steps: S31: reducing the moving speed of the laser beam (2) from the second speed to a third speed, and reducing the laser power of the laser beam (2) from the second power to a third power.

4. The laser welding method according to claim 1 or 2, characterized in that: The moving distance threshold is set to account for 50% to 90% of the total length of the welding path (11).

5. The laser welding method according to claim 3, characterized in that: In step S11, the increase in the moving speed of the laser beam (2) is linear with the moving distance of the laser, and the increase in the laser power of the laser beam (2) is linear with the moving distance of the laser.

6. The laser welding method according to claim 1 or 2, characterized in that: The welding path (11) is arranged at a groove (121) of an activation area (12) of the metal bipolar plate (1) and / or is arranged at a sealing area (13) of the metal bipolar plate (1).

7. The laser welding method according to claim 3, characterized in that: The laser welding method has one or more of the following characteristics: The first speed is 500 mm / s to 2000 mm / s, or 0 mm / s; The first power is 300W to 350W, or 0W; The second speed is 500 mm / s to 2000 mm / s; The second power is 300W to 350W; The third speed is 5 mm / s to 20 mm / s, or 0 mm / s; The third power is 200W to 250W, or 0W.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the laser welding method according to any one of claims 1 to 7 is implemented.

9. A computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the computer program, the laser welding method according to any one of claims 1 to 7 is implemented.

10. A laser welding device (100) for a metal bipolar plate (1) for a hydrogen fuel cell, the metal bipolar plate (1) being preset with a welding path (11), the welding path (11) comprising a welding start point (111) and a welding end point (112), characterized in that: The laser welding device (100) is used to perform the laser welding method according to any one of claims 1 to 7, and comprises a laser (101) and a judgment module (102), wherein the laser (101) is configured to apply and move a laser beam (2) along the welding path (11) from the welding starting point (111), and the judgment module (102) is configured to judge whether the moving distance of the laser beam (2) reaches a moving distance threshold, and if so, the laser (101) reduces the moving speed of the laser beam (2), and at the same time reduces the laser power of the laser beam (2) or maintains the laser power unchanged.

11. A metal bipolar plate (1) for a hydrogen fuel cell, characterized in that: The metal bipolar plate (1) is welded by the laser welding method according to any one of claims 1 to 7.

12. The metal bipolar plate (1) according to claim 11, characterized in that: The metal bipolar plate (1) has one or more of the following characteristics: The thickness of the metal bipolar plate (1) is less than 0.1 mm; The material of the metal bipolar plate (1) is selected from one or more of stainless steel, aluminum alloy, and titanium alloy; The width of the groove (121) of the active area (12) of the metal bipolar plate (1) is less than 2 mm.

13. A hydrogen fuel cell, characterized in that: The hydrogen fuel cell comprises the metal bipolar plate (1) according to claim 11 or 12.

14. A vehicle, characterized in that: The vehicle has the hydrogen fuel cell according to claim 13 .

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