Welding method, device, electronic device and storage medium for bipolar plates

Abstract

The application discloses a welding method and device of a bipolar plate, electronic equipment and a storage medium, and relates to the technical field of bipolar plate welding. The welding method of the application performs deformation detection on a target bipolar plate before welding to obtain a pre-welding detection result of the target bipolar plate, obtains a target mapping relationship between different welding parameters and the weld seam depth of the bipolar plate according to the welding quality of the bipolar plate under different welding parameters, determines target welding parameters of the target bipolar plate according to the pre-welding detection result and the target mapping relationship, and executes a bipolar plate welding task on the target bipolar plate according to the target welding parameters to weld two single bipolar plates into a bipolar plate. The welding method can adjust the parameters of the bipolar plate welding process in the welding process based on the deformation amount of the bipolar plate, makes the determination of the welding parameters more accurate, optimizes the welding process, and further improves the welding quality of the bipolar plate.

Description

Technical Field

[0001] This invention relates to the technical field of bipolar plate welding, and more particularly to a method, apparatus, electronic device, and storage medium for welding bipolar plates. Background Technology

[0002] A proton exchange membrane fuel cell (PEMFC) is a power generation device that uses hydrogen as fuel to directly convert chemical energy into electrical energy. The bipolar plate is the core component of the fuel cell, playing a role in gas distribution, hydrothermal management, current collection, and supporting the fuel cell stack. The commonly used material for bipolar plates is ultra-thin stainless steel sheet with a thickness of 0.07-0.1 mm. Typically, the raw material is first stamped into cathode and anode plates with precise flow channels. Two bipolar plates are then laser-welded together to form a "two-plate, three-field" bipolar plate structure. The welding quality of the bipolar plates directly affects the performance and lifespan of the fuel cell.

[0003] Therefore, improving the welding quality of bipolar plates is a technical problem that urgently needs to be solved. Summary of the Invention

[0004] The present invention provides a welding method, apparatus, electronic device and storage medium for bipolar plates, which improves the welding quality of bipolar plates.

[0005] The embodiments of the present invention provide the following solutions:

[0006] In a first aspect, embodiments of the present invention provide a welding method for bipolar plates, the method comprising:

[0007] Deformation detection is performed on the target electrode plate to obtain the pre-welding inspection results of the target electrode plate, wherein the target electrode plate is the single electrode plate to be welded;

[0008] Based on the welding quality of bipolar plates under different welding parameters, the target mapping relationship between different welding parameters and the weld depth of bipolar plates is obtained.

[0009] Based on the pre-welding inspection results and target mapping relationship, determine the target welding parameters of the target electrode plate;

[0010] The target electrode plate is welded according to the target welding parameters to weld two single electrode plates into a bipolar plate.

[0011] In an optional embodiment, before performing deformation detection on the target electrode, the method further includes:

[0012] The machining accuracy of the welding positioning holes on the target electrode plate is tested to obtain the machining deviation of the welding positioning holes;

[0013] When the processing deviation is less than the preset first threshold, an execution command is output to perform deformation detection on the target electrode plate;

[0014] When the processing deviation is greater than or equal to the first threshold, the target electrode plate is removed from the welding production line.

[0015] In one optional embodiment, deformation detection is performed on the target electrode plate to obtain pre-welding inspection results of the target electrode plate, including:

[0016] The flatness of the target electrode plate is measured to obtain the flatness deformation level of the target electrode plate;

[0017] Thickness change detection is performed on the target area of ​​the target electrode to obtain the thickness reduction level of the target electrode. The target area is the area on the target electrode that is close to the stamping surface.

[0018] The planar deformation level and thickness reduction level are determined as the pre-welding inspection results.

[0019] In an optional embodiment, after determining the planar deformation level and thickness reduction level as pre-weld inspection results, the method further includes:

[0020] When the planar deformation represented by the planar deformation level exceeds the preset upper limit of deformation, or the thickness reduction represented by the thickness reduction level exceeds the preset upper limit of thickness reduction, the target electrode plate is removed from the welding production line.

[0021] In one optional embodiment, the target welding parameters of the target electrode are determined based on the pre-welding inspection results and the target mapping relationship, including:

[0022] When the planar deformation represented by the pre-welding inspection results is less than the first preset range and the thickness reduction is less than the second preset range, the welding parameters that determine the weld depth to reach the single plate penetration state are determined as the target welding parameters in the target mapping relationship.

[0023] When the planar deformation represented by the pre-welding test results is less than the first preset range and the thickness reduction is within the second preset range, the parameter closest to the upper limit of the target parameter range is determined as the target welding parameter in the target mapping relationship. The target parameter range is the welding parameter range of the single plate melting state.

[0024] When the planar deformation represented by the pre-welding inspection results is within the first preset range and the thickness reduction is less than the second preset range, the parameter closest to the lower limit of the target parameter range is determined as the target welding parameter in the target mapping relationship.

[0025] When the planar deformation represented by the pre-welding inspection results is greater than the first preset range and the thickness reduction is greater than the second preset range, the welding parameters of the single plate penetration state are determined as the target welding parameters in the target mapping relationship.

[0026] In one optional embodiment, performing an electrode welding task on a target electrode plate according to target welding parameters includes:

[0027] Welding is performed along a preset welding path on the target electrode plate according to the target welding parameters, and welding monitoring data is acquired. The welding monitoring data includes at least the fluctuation value of welding power.

[0028] During the welding process, determine whether the fluctuation value exceeds the preset fluctuation limit;

[0029] If so, an alarm signal will be output and the target electrode plate will be removed from the welding production line;

[0030] If not, the target electrode plate will be identified when welding is completed, and the identification results and welding monitoring data will be stored accordingly.

[0031] In an optional embodiment, after performing electrode welding on the target electrode according to the target welding parameters, the method further includes:

[0032] When the target welding parameters are within the middle of the preset range of the target parameter range, a shooting command is output to the first shooting terminal. The target parameter range is the welding parameter range in which the weld depth reaches the single plate penetration state, and the first shooting terminal is a shooting terminal with a resolution lower than the second threshold.

[0033] Welding quality is inspected based on the first weld image output by the first imaging terminal, and the first inspection result is output.

[0034] When the target welding parameters are not within the preset range, a shooting command is output to the second shooting terminal, wherein the second shooting terminal is a shooting terminal with a resolution higher than the third threshold.

[0035] Welding quality is inspected based on the second weld image output by the second imaging terminal, and the second inspection result is output.

[0036] Secondly, embodiments of the present invention also provide a welding apparatus for bipolar plates, the apparatus comprising:

[0037] The first detection module is used to perform deformation detection on the target electrode plate in order to obtain the pre-welding detection results of the target electrode plate, wherein the target electrode plate is a single electrode plate to be welded;

[0038] The first acquisition module is used to obtain the target mapping relationship between different welding parameters and the weld depth of the bipolar plate based on the welding quality of the bipolar plate under different welding parameters.

[0039] The determination module is used to determine the target welding parameters of the target electrode plate based on the pre-welding inspection results and the target mapping relationship;

[0040] The execution module is used to perform electrode welding tasks on the target electrode plates according to the target welding parameters, so as to weld two single electrode plates into a bipolar plate.

[0041] Thirdly, embodiments of the present invention also provide an electronic device, including a processor and a memory, the memory being coupled to the processor, the memory storing instructions that, when executed by the processor, cause the electronic device to perform the steps of any of the methods in the first aspect.

[0042] Fourthly, embodiments of the present invention also provide a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of any of the methods in the first aspect.

[0043] The bipolar plate welding method, apparatus, electronic device, and storage medium of the present invention have the following advantages compared with the prior art:

[0044] The welding method of this invention involves performing deformation detection on the target electrode plate before welding to obtain the pre-welding detection results. Based on the welding quality of the bipolar plate under different welding parameters, a target mapping relationship between different welding parameters and the weld depth of the bipolar plate is obtained. Based on the pre-welding detection results and the target mapping relationship, the target welding parameters for the target electrode plate are determined. The electrode plate welding task is then performed on the target electrode plate according to the target welding parameters to weld two monopolar plates into a bipolar plate. This welding method can specifically adjust the parameters of the bipolar plate welding process based on the deformation of the electrode plate during the welding process, making the welding parameter determination more accurate, optimizing the welding process, and thus improving the welding quality of the bipolar plate. Attached Figure Description

[0045] To more clearly illustrate the technical solutions in the embodiments of this specification or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this specification. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0046] Figure 1 A flowchart illustrating a bipolar plate welding method provided in an embodiment of the present invention;

[0047] Figure 2-1 This is a schematic diagram of the structure of a bipolar plate provided in an embodiment of the present invention;

[0048] Figure 2-2 A schematic diagram illustrating the principle of thickness measurement of the target electrode plate provided in an embodiment of the present invention;

[0049] Figure 3-1 A cross-sectional schematic diagram of a bipolar plate in an unconnected state, provided in an embodiment of the present invention;

[0050] Figure 3-2 A schematic cross-sectional view of a bipolar plate in a single-plate fused state, provided in an embodiment of the present invention;

[0051] Figure 3-3 A schematic cross-sectional view of the bipolar plate in the double-plate fusion state provided in an embodiment of the present invention;

[0052] Figure 4 A MAP diagram of welding parameters provided for embodiments of the present invention;

[0053] Figure 5 This is a structural schematic diagram of the weld cross-section provided in an embodiment of the present invention;

[0054] Figure 6 This is a schematic diagram of a welding device for bipolar plates provided in an embodiment of the present invention.

[0055] Explanation of reference numerals in the attached drawings: 1-Bipolar plate, 2-Flow channel area, 3-Air cavity port, 4-Cooling cavity port, 5-Hydrogen cavity port, 6-Welding positioning hole, 7-Welding path, 8-Cathode plate, 9-Anode plate, 10-Weld seam. Detailed Implementation

[0056] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention are within the protection scope of the embodiments of the present invention.

[0057] In practical applications, the welding quality of bipolar plates is crucial, directly affecting their sealing performance and consequently the performance and safety of the fuel cell. Bipolar plates prevent hydrogen and air from mixing within the fuel cell stack and also prevent hydrogen leakage. Poor laser welding quality not only impacts the fuel cell's power generation performance but may also lead to combustion or explosion due to inadequate sealing. Therefore, improving the welding quality of bipolar plates is of great significance. The following embodiments of the invention will specifically illustrate how to improve the welding quality of bipolar plates.

[0058] Please see Figure 1 , Figure 1 This is a flowchart illustrating a bipolar plate welding method provided in an embodiment of the present invention. The welding method can be implemented on a control terminal of a bipolar plate welding production line. The control terminal can be an industrial computer or a computer device capable of running the welding method; no specific limitations are imposed here. The welding method includes:

[0059] S11. Deformation detection is performed on the target electrode plate to obtain the pre-welding detection results of the target electrode plate, wherein the target electrode plate is the single electrode plate to be welded.

[0060] Specifically, a bipolar plate is formed by welding two monopolar plates, which serve as the anode and cathode plates, respectively. The target plate can be either the anode or cathode plate, or it can include both. Deformation detection can be performed by taking pictures with a CCD (charge-coupled device) camera, and determining whether the target plate is warped based on the captured images; alternatively, deformation detection can be performed using a laser rangefinder. For example, the laser rangefinder can measure the distance at the four right-angle positions of the target plate, and the flatness of the target plate can be determined based on the measurement results. This flatness is then defined as the pre-welding inspection result of the target plate. The pre-welding inspection result characterizes the deformation detection result of the target plate before welding, and multiple inspection items can be set, such as flatness and stamping deformation.

[0061] Please see Figure 2-1 , Figure 2-1 This is a schematic diagram of the bipolar plate 1. A flow channel region 2 is located in the middle, and air inlets 3, cooling inlets 4, and hydrogen inlets 5 are located near both ends. When welding the bipolar plate 1, the cathode and anode plates need to be tightly fitted together, and the laser welding is controlled to proceed along a preset welding path 7. The bolded line in the diagram represents the welding path 7. Since the main area of ​​the bipolar plate is the flow channel region 2, the width of the reserved welding area is relatively narrow, typically as low as 0.7 mm. The space available for the welding fixture to hold the plates is small. Therefore, it is necessary to ensure the alignment accuracy of the cathode and anode plates, ensuring that the welding areas of the two plates overlap as much as possible in the width direction. To achieve this alignment accuracy, two welding positioning holes 6 can be provided on both the cathode and anode plates. For example, two circular holes can be machined diagonally on the target plate by stamping or laser cutting, serving as welding positioning holes 6. The diameter of the circular holes is set based on actual needs and can be set to 3 mm. Positioning pins with corresponding spacing are provided on the welding fixture. The welding positioning holes 6 cooperate with the positioning pins on the welding fixture to ensure the positioning accuracy of the cathode and anode plates during alignment and clamping.

[0062] Since the machining quality of the welding positioning holes directly affects the alignment accuracy, insufficient machining accuracy will result in the subsequent welding of bipolar plates failing to meet quality requirements. Therefore, in one specific embodiment, before performing deformation detection on the target electrode plate, the method further includes:

[0063] The machining accuracy of the welding positioning holes on the target electrode plate is inspected to obtain the machining deviation of the welding positioning holes. Machining accuracy inspection can include the inspection of the machining dimensions and the machining position of the welding positioning holes. For example, the machining diameter of the welding positioning holes is measured, and the measured dimension is compared with the design dimension; the result of the comparison is the machining deviation. Machining position inspection includes the distance between two welding positioning holes and the dimensions of their relative shapes; the positional deviation is also determined as the machining deviation. Of course, machining accuracy inspection can also include only the inspection of machining dimensions.

[0064] When the processing deviation is less than a preset first threshold, an execution command is output to perform deformation detection on the target electrode plate. When the processing deviation is greater than or equal to the first threshold, the target electrode plate is removed from the welding production line. The first threshold can be determined based on the quality requirements of the bipolar plate, such as based on the dimensional tolerances specified when designing the bipolar plate. Of course, the first threshold can also be set based on the quality control requirements for bipolar plate production, such as tolerance requirements controlled according to GB / T 1184-K level. When the processing deviation is less than the preset first threshold, it indicates that the processing accuracy of the welding positioning hole meets the positioning requirements during welding, and deformation detection continues; conversely, when the processing deviation is greater than or equal to the first threshold, it indicates that the positioning requirements are not met, and the target electrode plate is controlled to be removed from the line, preventing it from entering the subsequent production process. The target electrode plate can be removed from the line by a robot arm on the welding production line, or it can be controlled to be removed from the line by a transfer roller on the welding production line.

[0065] The micro-channels in the flow channel region are formed by stamping. After stamping, due to the ultra-thin nature of the single electrode plate, warping deformation is inevitable. This deformation leads to uncertainty regarding whether the cathode and anode plates can fit tightly under the clamping of the welding fixture, and it also affects the transfer and distribution of welding heat, thus impacting the welding quality. Therefore, in one specific embodiment, deformation detection is performed on the target electrode plate to obtain pre-welding inspection results, including:

[0066] The first step is to perform a flatness test on the target electrode to obtain its planar deformation level. Flatness testing can be performed using inspection equipment on the welding production line, and the planar deformation level is determined based on the equipment's output. Let PL be the denoted result of the flatness test, representing the bending deformation amplitude of the target electrode.

[0067] When the test result PL≥2mm, the plane deformation level is defined as level 3, which means that the plane deformation represented by the plane deformation level is greater than the preset upper limit of deformation. The warping deformation of the target electrode plate is too large, which has a great adverse effect on whether the cathode plate and anode plate can be tightly attached under the clamping of the welding fixture. The target electrode plate is removed from the welding production line.

[0068] When the test result is 1mm≤PL<2mm, it indicates that the target electrode plate has warping deformation, but the impact on the welding quality is limited, and it can proceed to the subsequent welding process. However, it is necessary to adjust the welding process parameters (such as increasing the laser power and decreasing the welding speed) to compensate for the poor flatness and the possibility that there may still be a small gap between the cathode plate and the anode plate under the clamping of the welding fixture, which may lead to the effect of incomplete welding. The flatness deformation level is defined as level 2.

[0069] When the test result is 0≤PL<1mm, it indicates that the warping deformation of the target electrode plate is small, and the cathode plate and anode plate can fit tightly together under the clamping of the welding fixture, which has no adverse effect on the subsequent welding quality. The planar deformation level is defined as level 1.

[0070] The second step involves detecting the thickness change in the target area of ​​the target electrode to obtain the thickness reduction level. The target area is the region on the target electrode near the stamping surface. This target area can be defined as the surface region near the flow channel, or it can include areas near all forming surfaces and the flow channel region within the detection range. The forming surface can be a stamped surface with forming features such as reinforcing ribs. The target electrode can be clamped using a welding fixture, and the thickness reduction level can be determined after measurement. Please refer to [link to relevant documentation]. Figure 2-2 , Figure 2-2 This is a schematic diagram illustrating the principle of thickness measurement of the target electrode in its flow channel region 2. The flow channel structure in the flow channel region is wave-like, with the distance between two wave peaks being the flow channel period F. The flow channel period F is as low as 1 mm, and the flow channel depth is as low as 0.3 mm. Therefore, this type of stamping characteristic will cause the plate thickness to be reduced. To accurately determine the thickness reduction level of the target electrode, the target electrode is first clamped using a welding fixture, making the welding fixture fit against the outer surface of the target electrode. Then, the first distance H1 between the rangefinder and the upper surface of the flow channel bottom of the target electrode, and the second distance H2 between the rangefinder and the surface of the welding fixture are measured using a laser rangefinder. Finally, the actual thickness of the target electrode after stamping is obtained based on the difference between the second distance H2 and the first distance H1. The thickness reduction amount is obtained by subtracting the actual plate thickness from the raw material thickness of the target electrode, and the thickness reduction level is determined based on the thickness reduction amount. Alternatively, the thickness reduction amount can be converted into a thickness reduction rate first, and then the thickness reduction level can be determined based on the thickness reduction rate. Taking the determination of thickness reduction level based on thickness reduction rate as an example, based on the formula:

[0071] R = (S0-S) / S0×100%, calculate the thickness reduction rate R, where S is the actual thickness of the target electrode plate after stamping, and S0 is the thickness of the raw material before stamping.

[0072] When the thickness reduction rate R ≥ 20%, it indicates that the target electrode plate is too thin after stamping. The thickness reduction level is defined as level 3, which means that the thickness reduction represented by the thickness reduction level is greater than the preset upper limit of thinning. It cannot provide sufficient sealing and has a significant impact on the subsequent welding quality. The target electrode plate is directly removed from the welding production line so that it cannot enter the subsequent welding process.

[0073] When the thickness reduction rate is 15% ≤ R < 20%, it indicates that the thickness reduction rate of the target electrode plate is slightly large, but the impact on the welding quality is small. It can proceed to the subsequent welding process, but it is necessary to adjust the welding process parameters in a targeted manner (such as reducing the laser power and increasing the welding speed) to compensate for the weld penetration defects that may be caused by the thinness of the single electrode plate. The thickness reduction level is defined as level 2.

[0074] When the thickness reduction rate R < 15%, it indicates that the thickness reduction rate is well controlled during stamping and can be considered to have no adverse effect on the subsequent welding quality. The thickness reduction level is defined as level 1.

[0075] The third step is to determine the planar deformation level and thickness reduction level as the pre-welding inspection results. The planar deformation level and thickness reduction level can be represented by binary numbers or Arabic numerals, without specific limitations. It should be noted that when the target electrode includes both a cathode plate and an anode plate, deformation inspection can be performed on both plates separately. If the inspection results are inconsistent, the larger value of the planar deformation level is taken. Similarly, when determining the thickness reduction level, the larger value of the thickness reduction level is taken. After obtaining the pre-welding inspection results of the target electrode, proceed to step S12.

[0076] S12. Based on the welding quality of bipolar plates under different welding parameters, obtain the target mapping relationship between different welding parameters and the weld depth of bipolar plates.

[0077] Specifically, welding parameters include at least welding speed and welding power; different welding parameters produce different weld qualities. The cross-sectional state of the weld after bipolar plate welding is classified into three types; please refer to [link / reference]. Figure 3-1 , Figure 3-2 and Figure 3-3 ,like Figure 3-1 As shown, the cathode plate 8 and anode plate 9 are not connected; only the upper cathode plate 8 is partially melted, and the two plates are not effectively connected. Figure 3-3 As shown, weld 10 is a double-plate penetration state, and the lower anode plate 9 is also penetrated by weld 10. However, there is usually no welding shielding gas under the lower plate, and the surface condition after welding is prone to oxidation and other defects. Figure 3-2 As shown, weld 10 represents a single-plate penetration state, meaning the upper plate is fully melted while the lower plate is partially melted but not fully melted. This ensures an effective connection between the cathode plate 8 and the anode plate 9 without affecting the post-weld surface condition of the lower anode plate 9, resulting in the best weld quality and representing the desired post-weld cross-section. Therefore, a target mapping relationship can be constructed based on the welding parameters corresponding to the single-plate penetration state. This target mapping relationship characterizes the correspondence between different welding parameters and welds of different depths within the single-plate penetration state. The target mapping relationship can be characterized using a data table or a MAP diagram.

[0078] like Figure 4As shown, Figure 4 This is a MAP (Mean Assurance Map) of welding parameters, with the horizontal axis representing welding power P (in W) and the vertical axis representing welding speed S (in mm / s). In bipolar laser welding, welding power and welding speed have the greatest impact on welding quality. Using an experimental design method, bipolar laser welding process experiments were conducted to investigate the effects of different combinations of welding power and welding speed parameters on the post-weld cross-sectional state, obtaining a standard MAP of welding power-welding speed-post-weld cross-section. Region A in the figure represents the welding parameter region where the bipolar plate is in an unconnected state; in this region, the welding power is too low and the welding speed is too high, making an unconnected state likely to occur. Region B represents the welding parameter region where the bipolar plate is in a single-plate penetration state; the welding power and welding speed are reasonably matched, achieving the desired single-plate penetration state. Region C represents the welding parameter region where the bipolar plate is in a double-plate penetration state; the welding power is too high and the welding speed is too low, making a double-plate penetration state likely to occur after welding.

[0079] When constructing the target mapping relationship, the welding parameter region of the single plate's penetration state can be divided into multiple parameter intervals. The weld depth of each parameter interval can be determined, and the two can be stored accordingly to construct a target mapping relationship that satisfies welding quality requirements. Please continue reading. Figure 4 The diagram divides region B into three regions: region I, region II, and region III. Each region corresponds to a different weld depth. After obtaining the target mapping relationship between different welding parameters and the weld depth of the bipolar plate, the process proceeds to step S13.

[0080] S13. Determine the target welding parameters of the target electrode plate based on the pre-welding inspection results and the target mapping relationship.

[0081] Specifically, the deformation of the target electrode plate can be determined through pre-welding inspection results. Different welding parameters are required under different deformations. Based on this characteristic, the applicable welding parameters can be determined in the target mapping relationship to ensure the weld depth of the bipolar plate. The welding parameters determined in the target mapping relationship are then used as the target welding parameters.

[0082] For example, based on the pre-welding inspection results and the target mapping relationship, the target welding parameters of the target electrode are determined, including:

[0083] When the planar deformation characterized by the pre-welding inspection results is less than the first preset range, and the thickness reduction is less than the second preset range, it indicates that the warping deformation and thickness reduction rate of the target electrode plate are well controlled. In the target mapping relationship, the welding parameters that allow the weld depth to reach the single-plate penetration state are determined as the target welding parameters. Still using... Figure 4For example, interval B is the target parameter interval for the single-plate penetration state. Applicable target welding parameters can be selected within the target parameter interval based on the requirements of balancing welding efficiency and welding quality. When the pre-weld inspection results are characterized by both planar deformation level and thickness reduction level, when the planar deformation level is level 1, the planar deformation is determined to be less than the first preset interval; when the thickness reduction level is level 1, the thickness reduction is determined to be less than the second preset interval.

[0084] When the planar deformation characteristic of the pre-welding inspection results is less than the first preset range, and the thickness reduction is within the second preset range, it indicates that the warpage deformation of the target electrode is well controlled, but the thinning rate is slightly large. Therefore, it is necessary to specifically adjust the welding process parameters. In the target mapping relationship, the parameters closest to the upper limit of the target parameter range are determined as the target welding parameters. The target parameter range is the welding parameter range for the single-plate penetration state. Please continue reading. Figure 4 The target parameter range can be divided into three zones: Zone I, Zone II, and Zone III. The upper limit of the target parameter range is the welding parameter of Zone I. Therefore, the target welding parameter can be selected in Zone I based on actual needs to compensate for weld penetration defects that may be caused by the thinness of the target electrode plate. Similarly, when the planar deformation level is 1, the planar deformation is determined to be less than the first preset range; when the thickness reduction level is 2, the thickness reduction is determined to be within the second preset range.

[0085] When the planar deformation characterized by the pre-welding test results is within the first preset range and the thickness reduction is less than the second preset range, it indicates that the thickness reduction rate of the target electrode plate is well controlled, but the warping deformation is slightly large. It is necessary to adjust the welding process parameters in a targeted manner and determine the parameters that are close to the lower limit of the target parameter range in the target mapping relationship as the target welding parameters. Figure 4 In this context, the lower limit of the target parameter range is the welding parameter of Zone III. The welding parameters determined in Zone III can be configured as the target welding parameters to compensate for the potential weld defects caused by slightly larger warping deformation of the target electrode plate. When the planar deformation level is 2, the planar deformation is determined to be within the first preset range; when the thickness reduction level is 1, the thickness reduction is determined to be less than the second preset range.

[0086] When the planar deformation indicated by the pre-welding inspection results is greater than the first preset range and the thickness reduction is greater than the second preset range, it indicates that the warping deformation and thickness reduction rate of the target electrode plate are both large. The two situations require opposite adjustments to the welding process parameters, thus canceling each other out. In the target mapping relationship, the welding parameters for the single-plate penetration state are determined as the target welding parameters; that is, the welding parameters selected for zones I, II, and III can all be used as target welding parameters. After determining the target welding parameters for the target electrode plate, proceed to step S14.

[0087] S14. Perform electrode welding on the target electrode plate according to the target welding parameters to weld the two single electrode plates into a bipolar plate.

[0088] Specifically, the electrode welding task can be completed with the help of a welding fixture. The welding fixture holds the target electrode and ensures that the alignment accuracy meets the preset requirements. The laser welder is controlled to emit light, and the output power is the welding power corresponding to the target welding parameters. Welding is carried out along the welding path on the target electrode. The path movement speed during the welding process is the welding speed corresponding to the target welding parameters. When welding is completed on all paths, the target electrode is considered to have completed the electrode welding task. The cathode and anode plates are welded into a bipolar plate.

[0089] In practical applications, the stability of bipolar plate welding quality is difficult to guarantee, mainly due to the following reasons: First, the bipolar plate blank is an ultra-thin plate, which is very sensitive to laser welding process parameters. Even slight fluctuations in the mains voltage or equipment voltage can cause defects such as incomplete welds and burn-through. Second, bipolar plate welding is very sensitive to the design and precision of the fixture. This is mainly because the bipolar plate structure is complex, with the main area being the flow channel region. The area reserved for welding is very narrow (as low as 0.7mm), leaving very little space for the fixture to hold it. Furthermore, the bipolar plate has a large surface area and a long welding path. The welding fixture must ensure that the anode and cathode plates are 100% tightly fitted on all welding paths; otherwise, defects such as incomplete welds and burn-through will also occur.

[0090] Due to factors such as voltage fluctuations in the power grid and laser welding equipment, the laser output power fluctuates. Although this can be controlled by installing a voltage stabilizer, the extremely thin thickness of the cathode and anode plates (typically 0.07-0.1 mm) means that even slight fluctuations in laser power can significantly impact the weld penetration and width, potentially causing defects such as burn-through or incomplete welds. Therefore, in one specific implementation, the electrode plate welding task is performed on the target electrode plate according to the target welding parameters, including:

[0091] The first step involves welding along a preset welding path on the target bipolar plate according to the target welding parameters, and acquiring welding monitoring data. This data includes at least the fluctuation value of the welding power. Welding monitoring data can be obtained through the monitoring system of the welding production line. Using a single bipolar plate workpiece as a unit, the monitoring system continuously records the laser output power and scanning speed corresponding to each welding point and transmits this data to the computer system.

[0092] The second step is to determine whether the fluctuation value exceeds the preset fluctuation limit during the welding process. The fluctuation limit can be set based on actual needs or calibration experiments, as long as it meets the welding quality requirements of the bipolar plate. Intelligent algorithm software can be used to analyze the welding monitoring data to determine whether the fluctuation value exceeds the fluctuation limit.

[0093] Thirdly, if the fluctuation value exceeds the fluctuation limit, it indicates that the welding parameters do not meet the target welding parameter settings. An alarm signal is then output, and the target electrode plate is removed from the welding production line. Simultaneously, based on the abnormal process parameters falling into the corresponding area on the MAP chart, the defect type of the unqualified welding position can be determined. For example, if it reaches a state of incomplete connection or double-plate fusion, the welding parameters can be adjusted in a timely manner to avoid welding quality problems during batch welding. If the fluctuation value is less than or equal to the fluctuation limit, the target electrode plate is identified upon completion of welding, and the identification result and welding monitoring data are stored accordingly. The above functions can be implemented based on a monitoring system, for example, a system configured to continuously track and store up to millions of workpiece data points, and to easily export this data. After welding is completed, a QR code or production serial number is marked on the surface of the bipolar plate using laser welding equipment. Identification is achieved through the QR code or production serial number. When a bipolar plate malfunctions or has welding defects, QR code recognition technology is used to track the welding parameters of that bipolar plate, ensuring data traceability.

[0094] Currently, quality inspection methods for bipolar laser welding fall into two main categories: First, destructive testing, including destructive mechanical experiments and cross-sectional observation, is the most direct and reliable method for assessing weld quality. However, it is an offline method, inefficient, and cannot achieve 100% inspection, making it unsuitable for automated large-scale industrial production. Second, non-destructive testing, where each bipolar plate must be tested for airtightness using specialized tooling after production. Only bipolar plates that pass 100% inspection can be used to assemble fuel cells. However, testing the airtightness of each bipolar plate after production is extremely inefficient, taking approximately 1-2 minutes per plate. This low efficiency prevents real-time monitoring and timely adjustments, hindering quality assurance in mass production. Therefore, while destructive cross-sectional observation is the most direct and reliable method for inspecting weld dimensions, it remains inefficient and cannot achieve 100% inspection.

[0095] During the welding process of bipolar plates, other factors can still adversely affect the welding quality, such as localized oil stains or other foreign matter on the plate surface, and unstable clamping by the welding fixture. Therefore, in one specific embodiment, after completing the plate welding task, the method further includes machine vision inspection of the bipolar plate welding quality. Please refer to... Figure 5 , Figure 5This is a schematic diagram of the weld cross-section. The weld width W is related to the weld depth H; the wider the weld surface width W, the deeper the weld depth H. Through process experiments, it can be determined that when the weld depth is 1.2D≤H≤1.8D (D is the electrode plate thickness), the corresponding weld width falls within the width range (W1, W2). Therefore, a visual inspection system can be used to inspect the weld width W of the bipolar plate to confirm whether it meets the preset standard (W1, W2). The visual inspection system acquires a surface image of the bipolar plate, and the weld width is identified based on the surface image. If the weld width is within the width range, it indicates that the welding quality meets production requirements; otherwise, it indicates that the welding quality of the bipolar plate does not meet production requirements. When the weld width is not within the width range, an automatic alarm signal can be set to prompt the system, filter out unqualified bipolar plates, and promptly investigate and control abnormal points in the welding process.

[0096] Since machine vision inspection involves a large amount of data, using a high-definition camera to capture surface images would further increase the amount of data to be processed due to the high resolution of the surface images. Therefore, when the target welding parameters are within a preset range in the middle of the target parameter interval, a shooting command is output to the first shooting terminal. Here, the target parameter interval is the welding parameter interval where the weld depth reaches the single-plate penetration state, and the first shooting terminal is a shooting terminal with a resolution lower than a second threshold. Welding quality inspection is performed based on the first weld image output by the first shooting terminal, and a first inspection result is output.

[0097] Still with Figure 4 Taking the welding parameter range as an example, when the welding parameters monitored during welding are in Zone II, the determined target welding parameters are far from the welding parameters of the unconnected zone and the double plate penetration zone. The risk of non-compliance of bipolar plate welding is low, and the probability of the weld width being within the preset range is high. A first shooting terminal with a lower resolution is used for taking pictures and machine vision inspection to reduce computational redundancy and improve the inspection efficiency of bipolar plates.

[0098] When the target welding parameters are not within the preset range, it indicates that the target welding parameters may be in Zone I, near the unconnected area; or in Zone III, near the welding parameter area where the double-plate penetration is located. The risk of unqualified bipolar plate welding increases relatively, and the weld width may approach the limit. Therefore, a shooting command is output to the second imaging terminal, which has a resolution higher than the third threshold. Welding quality inspection is performed based on the second weld image output by the second imaging terminal, and a second inspection result is output. This achieves accurate image processing and comparison, reducing the false judgment rate of welding quality inspection.

[0099] Based on the same technical concept as the welding method, embodiments of the present invention also provide a welding apparatus for bipolar plates. Please refer to [link to relevant documentation]. Figure 6 , Figure 6 This is a schematic diagram of the welding apparatus, which includes:

[0100] The first detection module 601 is used to perform deformation detection on the target electrode plate in order to obtain the pre-welding detection results of the target electrode plate, wherein the target electrode plate is a single electrode plate to be welded.

[0101] The first obtaining module 602 is used to obtain the target mapping relationship between different welding parameters and the weld depth of the bipolar plate based on the welding quality of the bipolar plate under different welding parameters.

[0102] The determination module 603 is used to determine the target welding parameters of the target electrode plate based on the pre-welding inspection results and the target mapping relationship.

[0103] The execution module 604 is used to perform electrode welding tasks on the target electrode plate according to the target welding parameters, so as to weld two single electrode plates into a bipolar plate.

[0104] In one optional embodiment, the welding apparatus further includes:

[0105] The second detection module is used to detect the machining accuracy of the welding positioning holes on the target electrode plate in order to obtain the machining deviation of the welding positioning holes.

[0106] The first output module is used to output an execution command to perform deformation detection on the target electrode plate when the processing deviation is less than a preset first threshold.

[0107] The control module is used to remove the target electrode plate from the welding production line when the processing deviation is greater than or equal to a first threshold.

[0108] In one optional embodiment, the first detection module includes:

[0109] The first submodule is used to perform flatness detection on the target electrode plate and obtain the flatness deformation level of the target electrode plate.

[0110] The second submodule is used to detect the thickness change of the target area of ​​the target electrode plate and obtain the thickness reduction level of the target electrode plate. The target area is the area on the target electrode plate that is close to the stamping surface.

[0111] The first determination submodule is used to determine the planar deformation level and thickness reduction level as the pre-welding inspection results.

[0112] In an optional embodiment, the first detection module further includes:

[0113] The control submodule is used to remove the target electrode plate from the welding production line when the planar deformation level represents a planar deformation amount greater than a preset deformation limit, or the thickness reduction level represents a thickness reduction amount greater than a preset thinning limit.

[0114] In one alternative embodiment, the determining module includes:

[0115] The second determining submodule is used to determine the welding parameters that the weld depth reaches the single plate penetration state in the target mapping relationship when the planar deformation represented by the pre-welding test results is less than the first preset range and the thickness reduction is less than the second preset range.

[0116] The third determining submodule is used to determine the parameters that are close to the upper limit of the target parameter range as target welding parameters in the target mapping relationship when the planar deformation represented by the pre-welding test results is less than the first preset range and the thickness reduction is within the second preset range. The target parameter range is the welding parameter range of the single plate melting state.

[0117] The fourth determination submodule is used to determine the target welding parameter in the target mapping relationship when the planar deformation represented by the pre-welding test results is in the first preset range and the thickness reduction is less than the second preset range.

[0118] The fifth determination submodule is used to determine the welding parameters of the single plate penetration state as the target welding parameters in the target mapping relationship when the planar deformation represented by the pre-welding inspection results is greater than the first preset range and the thickness reduction is greater than the second preset range.

[0119] In one optional embodiment, the execution module includes:

[0120] The acquisition submodule is used to perform welding along a preset welding path on the target electrode plate according to the target welding parameters, and to acquire welding monitoring data, wherein the welding monitoring data includes at least the fluctuation value of welding power.

[0121] The sixth determination submodule is used to determine whether the fluctuation value is greater than the preset fluctuation limit during the welding process;

[0122] The output submodule is used to output an alarm signal and remove the target electrode plate from the welding production line when the fluctuation value exceeds the fluctuation limit.

[0123] The processing submodule is used to identify the target electrode plate when the fluctuation value is less than or equal to the fluctuation limit, and to store the corresponding marking results and welding monitoring data.

[0124] In one optional embodiment, the welding apparatus further includes:

[0125] The second output module is used to output a shooting command to the first shooting terminal when the target welding parameters are in the middle of the preset range of the target parameter range. The target parameter range is the welding parameter range in which the weld depth reaches the single plate melting state, and the first shooting terminal is a shooting terminal with a resolution lower than the second threshold.

[0126] The third output module is used to perform welding quality inspection based on the first weld image output by the first imaging terminal and output the first inspection result;

[0127] The fourth output module is used to output a shooting command to the second shooting terminal when the target welding parameters are not within the middle preset range, wherein the second shooting terminal is a shooting terminal with a resolution higher than the third threshold.

[0128] The fifth output module is used to perform welding quality inspection based on the second weld image output by the second imaging terminal and output the second inspection result.

[0129] Based on the same technical concept as the welding method, embodiments of the present invention also provide an electronic device, including a processor and a memory, the memory being coupled to the processor, the memory storing instructions, which, when executed by the processor, cause the electronic device to perform the steps of any of the welding methods.

[0130] Based on the same technical concept as the welding method, embodiments of the present invention also provide a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of any one of the welding methods.

[0131] The technical solutions provided in the embodiments of the present invention have at least the following technical effects or advantages:

[0132] 1. The welding method of the present invention performs deformation detection on the target electrode plate before welding to obtain the pre-welding detection results of the target electrode plate. Based on the welding quality of the bipolar plate under different welding parameters, a target mapping relationship between different welding parameters and the weld depth of the bipolar plate is obtained. Based on the pre-welding detection results and the target mapping relationship, the target welding parameters of the target electrode plate are determined. The electrode plate welding task is then performed on the target electrode plate according to the target welding parameters to weld two monopolar plates into a bipolar plate. This welding method can specifically adjust the parameters of the bipolar plate welding process based on the deformation of the electrode plate during the welding process, making the welding parameters more accurate, optimizing the welding process, and thus improving the welding quality of the bipolar plate.

[0133] 2. After the bipolar plates are welded, online machine vision inspection can be performed, overcoming the shortcomings of existing technologies that typically rely on post-constructive testing or inefficient offline airtightness testing for bipolar plate welding quality inspection. This allows for real-time online monitoring of bipolar plate welding quality, improving inspection efficiency and facilitating mass production. Furthermore, based on the location of the target welding parameters, different resolution imaging terminals can be used to improve image processing and comparison efficiency while reducing the false positive rate.

[0134] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0135] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (modules, systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0136] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0137] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0138] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0139] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A method for welding bipolar plates, characterized in that, The method includes: Deformation detection is performed on the target electrode plate to obtain the pre-welding inspection results of the target electrode plate, wherein the target electrode plate is a single electrode plate to be welded; Based on the welding quality of the bipolar plate under different welding parameters, a target mapping relationship between the different welding parameters and the weld depth of the bipolar plate is obtained; When the planar deformation represented by the pre-welding inspection results is less than the first preset range and the thickness reduction is less than the second preset range, the welding parameters in the target mapping relationship that allow the weld depth to reach the single-plate penetration state are determined as the target welding parameters. When the planar deformation represented by the pre-welding test result is less than the first preset range and the thickness reduction is within the second preset range, the parameter closer to the upper limit of the target parameter range in the target mapping relationship is determined as the target welding parameter, wherein the target parameter range is the welding parameter range of the single plate melting state; When the planar deformation represented by the pre-welding inspection result is located in the first preset range and the thickness reduction is less than the second preset range, the parameter closer to the lower limit of the target parameter range is determined as the target welding parameter in the target mapping relationship; When the planar deformation represented by the pre-welding test results is greater than the first preset range and the thickness reduction is greater than the second preset range, the welding parameters of the single plate penetration state are determined as the target welding parameters in the target mapping relationship. According to the target welding parameters, the target electrode plate is subjected to electrode plate welding task to weld the two single electrode plates into the bipolar plate.

2. The welding method for bipolar plates according to claim 1, characterized in that, Before performing deformation detection on the target electrode, the method further includes: The machining accuracy of the welding positioning holes on the target electrode plate is tested to obtain the machining deviation of the welding positioning holes; When the processing deviation is less than a preset first threshold, an execution command is output to perform deformation detection on the target electrode plate; When the processing deviation is greater than or equal to the first threshold, the target electrode plate is removed from the welding production line.

3. The welding method for bipolar plates according to claim 1, characterized in that, The deformation detection of the target electrode plate to obtain the pre-welding inspection results of the target electrode plate includes: The flatness of the target electrode plate is measured to obtain the plane deformation level of the target electrode plate; Thickness change detection is performed on the target area of ​​the target electrode plate to obtain the thickness reduction level of the target electrode plate, wherein the target area is the area on the target electrode plate near the stamping surface; The planar deformation level and the thickness reduction level are determined as the pre-welding inspection results.

4. The welding method for bipolar plates according to claim 3, characterized in that, After determining the planar deformation level and the thickness reduction level as the pre-welding inspection results, the method further includes: When the planar deformation represented by the planar deformation level is greater than the preset upper limit of deformation, or the thickness reduction represented by the thickness reduction level is greater than the preset upper limit of thickness reduction, the target electrode plate is removed from the welding production line.

5. The welding method for bipolar plates according to claim 1, characterized in that, The step of performing electrode welding on the target electrode according to the target welding parameters includes: Welding is performed along a preset welding path on the target electrode plate according to the target welding parameters, and welding monitoring data is obtained, wherein the welding monitoring data includes at least the fluctuation value of welding power; During the welding process, it is determined whether the fluctuation value is greater than a preset fluctuation limit. If so, an alarm signal is output, and the target electrode plate is removed from the welding production line; If not, the target electrode plate is identified when welding is completed, and the identification result and the welding monitoring data are stored accordingly.

6. The welding method for bipolar plates according to claim 1, characterized in that, After performing electrode welding on the target electrode according to the target welding parameters, the method further includes: When the target welding parameters are within a preset range in the middle of the target parameter range, a shooting command is output to the first shooting terminal, wherein the target parameter range is the welding parameter range in which the weld depth reaches the single plate penetration state, and the first shooting terminal is a shooting terminal with a resolution lower than the second threshold. Welding quality is inspected based on the first weld image output by the first imaging terminal, and a first inspection result is output. When the target welding parameters are not within the preset range in the middle, a shooting command is output to the second shooting terminal, wherein the second shooting terminal is a shooting terminal with a resolution higher than the third threshold. Welding quality is inspected based on the second weld image output by the second imaging terminal, and a second inspection result is output.

7. A welding apparatus for bipolar plates, characterized in that, The device includes: The first detection module is used to perform deformation detection on the target electrode plate to obtain the pre-welding detection result of the target electrode plate, wherein the target electrode plate is a single electrode plate to be welded; The first obtaining module is used to obtain the target mapping relationship between the different welding parameters and the weld depth of the bipolar plate based on the welding quality of the bipolar plate under different welding parameters. The determination module is used to determine the target welding parameters of the target electrode plate based on the pre-welding inspection results and the target mapping relationship. The determination module includes: a second determination submodule, used to determine the welding parameters in the target mapping relationship where the weld depth reaches the single-plate penetration state when the planar deformation represented by the pre-welding inspection results is less than a first preset interval and the thickness reduction is less than a second preset interval; and a third determination submodule, used to determine the welding parameters closest to the target electrode plate in the target mapping relationship when the planar deformation represented by the pre-welding inspection results is less than the first preset interval and the thickness reduction is within the second preset interval. The parameters at the upper limit of the range are the target welding parameters, where the target parameter range is the welding parameter range of the single plate penetration state; the fourth determining submodule is used to determine the parameters closer to the lower limit of the target parameter range as target welding parameters in the target mapping relationship when the planar deformation represented by the pre-welding inspection results is in the first preset range and the thickness reduction is less than the second preset range; the fifth determining submodule is used to determine the welding parameters of the single plate penetration state as target welding parameters in the target mapping relationship when the planar deformation represented by the pre-welding inspection results is greater than the first preset range and the thickness reduction is greater than the second preset range. The execution module is used to perform electrode welding tasks on the target electrode plate according to the target welding parameters, so as to weld two single electrode plates into the bipolar plate.

8. An electronic device, characterized in that, The device includes a processor and a memory, the memory being coupled to the processor, the memory storing instructions that, when executed by the processor, cause the electronic device to perform the steps of the method according to any one of claims 1-6.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When executed by a processor, the program implements the steps of the method described in any one of claims 1-6.

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