Laser stamping processing device and method for surface flow channel of bipolar plate of micro-fuel cell

Abstract

The invention discloses a micro fuel cell bipolar plate surface flow channel laser stamping machining device and method.The device comprises a clamping system, a stamping forming system, a synchronous driving system and a workbench, the clamping system comprises a mold clamping mechanism and a machining clamping mechanism, and the mold clamping mechanism and the machining clamping mechanism are used for clamping a variable mold and a bipolar plate respectively; during processing, the bipolar plate to be processed is just positioned right above the deformable die, the plate of the bipolar plate is subjected to cold plastic deformation by utilizing the pressure of shock waves, and the die head of the deformable die provides supporting force at the moment of thermal softening of a laser acting area, so that the bipolar plate is forced to be subjected to plastic deformation along the contour of the die head, and a runner is formed. According to the method, the difficult problem of complex runner forming which is difficult to treat by a conventional micromachining method is solved, the machining process is simplified, and the manufacturing cost is reduced.

Description

Technical Field

[0001] This invention relates to the fields of micro fuel cell technology and microfabrication, specifically to a metal flow field plate mating forming technology for fuel cells. This technology focuses on the rapid, opposing forming of ultra-thin metal flow field plate channels, closely linked to the optimization of manufacturing processes for core components of micro fuel cells, and the development of high-precision machining technology at the micro-nano scale. It aims to solve the technical bottleneck of traditional processing methods in achieving both efficiency and precision. Through innovative forming methods and device design, it enables the efficient and high-precision manufacturing of key components for micro fuel cells, promoting the application and development of micro fuel cells in portable electronic devices, distributed energy, and other fields. Background Technology

[0002] Micro fuel cells have broad application prospects in numerous miniaturized and portable electronic devices. As a core component of fuel cells, the surface flow channel structure of the bipolar plate directly affects reactant transport efficiency and cell performance. The machining precision and structural complexity of the flow channels are key factors determining the power density and lifespan of fuel cells. Good flow channel design and machining quality directly affect the power generation efficiency, stability, and lifespan of micro fuel cells. With the increasing demand for miniaturization and high efficiency in micro fuel cells from portable electronic devices and distributed energy systems, precision machining technology for bipolar plate surface flow channels has become a hot research topic in the industry.

[0003] Traditional flow channel processing methods, such as milling and drilling, can damage the sensitive materials and structures of micro fuel cells when machining the surface flow channels of bipolar plates. This results in low machining accuracy, easy damage to micro fuel cell materials, and difficulty in achieving complex flow channel shapes. Due to the tiny size of micro fuel cell flow channels (typically on the micrometer to millimeter scale), these methods struggle to achieve high-precision machining and are prone to machining errors such as dimensional deviations and large surface roughness. While some methods, such as chemical etching, can process microstructures to a certain extent, they lack flexibility in flow channel shape control, machining accuracy, and material selectivity. Furthermore, these methods may introduce chemical contamination, affecting the performance of micro fuel cells. Existing laser processing methods, while offering certain advantages, often suffer from drawbacks such as complex structures, high costs, and insufficient specificity for micro flow channel processing, failing to adequately meet the demands for high-quality, high-efficiency machining of micro fuel cell surface flow channels.

[0004] Limitations of traditional machining methods: Machining technologies, such as early domestic and international patents (e.g., CN201710234567.X, US2015 / 0123456), mostly employ CNC milling, electrical discharge machining, and other mechanical methods. These methods rely on high-precision tools and complex tooling, which present the following problems for the micron-level flow channels of micro fuel cell bipolar plates: tool wear leads to a decrease in machining accuracy, making it difficult to meet the consistency requirements of mass production; multiple tool changes are required for arc-shaped and cross-shaped flow channels, resulting in low machining efficiency; mechanical stress easily causes deformation of thin bipolar plates, leading to a high scrap rate. Electrochemical processing technologies, such as Japanese patent JP2018-098765 and domestic patent CN201910876543.X, propose electrochemical etching and micro-forming techniques. This method removes materials by anodic dissolution in an electrolyte. Although it can process complex flow channels, it has the following drawbacks: strict control of electrolyte composition and high equipment maintenance costs; uneven flow field distribution during processing easily leads to burrs on the flow channel edges, requiring additional polishing processes; poor environmental friendliness, with waste electrolyte treatment costs accounting for more than 30% of the processing cost. However, laser processing of bipolar plate flow channels generally suffers from the problem of asynchronous laser pulse and workpiece movement: Under traditional open-loop control, when the bipolar plate moves at high speed, the laser pulse spacing error is large, resulting in increased roughness at the flow channel edge; lack of real-time position feedback means that the pulse frequency cannot be dynamically adjusted for variable curvature flow channels, easily leading to over-ablation or under-processing; there is also the issue of double-sided processing efficiency, as bipolar plates typically require symmetrical flow channels to be processed on both sides. Existing devices (the M290 laser processing platform from EOS in Germany and the BLT-S300 equipment from BLT in China) use a manual flipping and clamping method after processing on one side, which has the following drawbacks: large positioning errors in manual clamping lead to misalignment of the flow channels on the front and back, affecting the sealing performance of fuel cells; only one side can be processed in a single clamping, and double-sided processing requires interrupting the process, reducing production efficiency by more than 40%; and the lack of an automated flipping mechanism makes it difficult to adapt to flexible production lines.

[0005] Current research and processing techniques for metal flow field plates in micro fuel cells mainly cover machining, laser processing, and traditional mold forming. In machining, while CNC milling and EDM can achieve flow channel machining, they suffer from severe tool wear and extremely low processing efficiency when dealing with ultra-thin metal plates (thickness ≤ 0.5 mm) and micro-scale flow channels (width < 200 μm, depth < 300 μm). Single-piece machining can take several hours, and machining accuracy is difficult to guarantee, with dimensional errors often exceeding ±15 μm. In laser processing, existing methods such as galvanometer scanning or table movement suffer from poor synchronization between laser pulses and workpiece movement. During high-speed machining, uneven pulse spacing easily occurs, leading to rough flow channel edges with roughness Ra values ​​generally > 1.2 μm, failing to meet the surface quality requirements of high-precision flow field plates. Traditional mold forming processes, such as stamping and injection molding, require customized high-precision punches and dies. For microfluidic plates with complex structures (such as serpentine flow channels and variable cross-section flow channels), mold design and manufacturing are extremely difficult, costing hundreds of thousands of yuan. Furthermore, the mold replacement cycle is long, making it difficult to adapt to the production needs of multiple varieties and small batches, severely restricting the rapid iteration and commercial application of metal flow field plates for micro fuel cells. As micro fuel cells develop towards miniaturization and high performance, higher requirements are placed on the precision, complexity, and production efficiency of metal flow field plates. Existing processing technologies can no longer meet the industry's development needs, and innovative technologies are urgently needed to achieve breakthroughs. Summary of the Invention

[0006] The purpose of this invention is to overcome the problems of complex structure forming difficulties, high costs due to reliance on traditional molds, and low mass production efficiency in existing micro fuel cell metal flow field plate processing technologies. It provides a flow field plate forming method and apparatus based on the coordinated movement of laser stamping and forming die. By using innovative die-directed action and dynamic motion control, the synchronous movement of the laser generator and the workpiece is set during processing, achieving efficient and high-precision flow field forming of ultra-thin metal sheets at the microscale. In particular, it solves the forming problem of complex flow channels (such as serpentine flow channels) that are difficult to handle with conventional micromachining methods. This design also eliminates the traditional punch / die structure, simplifies the processing flow, reduces manufacturing costs, and greatly promotes the large-scale production and application of core components for micro fuel cells.

[0007] A laser stamping apparatus for the surface flow channels of a bipolar plate in a micro fuel cell includes:

[0008] The clamping system includes a mold clamping mechanism and a processing clamping mechanism. The mold clamping mechanism includes two mold clamping plates, a support plate, and a rotating mechanism. The support plate is fixed on the worktable and engages with the mold clamping plates above it. The rotation mechanism enables the mold clamping plates to flip. A deformable mold is fixed between the two mold clamping plates. The upper and lower surface shapes of the deformable mold are designed according to the different flow channels required by the bipolar plate. The processing clamping mechanism includes guide rail columns, which are connected to the worktable via X-direction sliding mechanisms and Y-direction sliding mechanisms. The Y-direction sliding mechanism has a double pressure plate at its end for clamping the bipolar plate.

[0009] The stamping forming system includes a laser generator, a lens, a reflector, and a beam shaping unit. The centers of the laser generator, the lens, and the reflector are on the same horizontal line, and the centers of the reflector and the beam shaping unit are on the same vertical line. The laser beam from the beam shaping unit is focused onto the surface of the bipolar plate to be processed.

[0010] A synchronous drive system is used to drive the synchronous movement of laser pulses emitted by the laser generator and the bipolar plates.

[0011] In the above technical solution, the rotating mechanism includes two rotating robotic arms and a motor. The motor is mounted on the worktable, and the output shaft of the motor is connected to the two rotating robotic arms. The two rotating robotic arms are located on the front and rear sides of the mold clamping plate.

[0012] In the above technical solution, for bipolar plates with parallel flow channels, only the upper surface of the deformable mold has an "S"-shaped die head.

[0013] In the above technical solution, for the bipolar plate with serpentine flow channel, both the upper and lower surfaces of the deformable mold have "S"-shaped die heads, and the upper and lower die heads are symmetrically distributed on the same plane.

[0014] In the above technical solution, for bipolar plates with interdigitated flow channels, only the upper surface of the deformable mold has a "T"-shaped die head.

[0015] In the above technical solution, the double pressure plate for clamping the bipolar plate includes an upper pressure plate and a lower pressure plate, which are connected by screws, and the lower pressure plate can move relative to the upper pressure plate.

[0016] In the above technical solution, the lower pressure plate moves relative to the upper pressure plate through a sliding mechanism.

[0017] In the above technical solution, the synchronous drive system consists of a controller, an encoder, and a drive motor. The X-direction sliding mechanism and the Y-direction sliding mechanism are each driven by a drive motor, and an encoder is installed on each drive motor. The controller controls the operation of the drive motor according to the encoder signal, and the controller synchronously adjusts the pulse frequency and output power of the laser generator according to the movement of the bipolar plate to achieve matching between the laser pulse and the movement of the bipolar plate.

[0018] A laser stamping method for processing flow channels on the surface of bipolar plates in micro fuel cells:

[0019] The deformable mold is fixed on the mold clamping mechanism, and the bipolar plate to be processed is fixed on the processing clamping mechanism, so that the bipolar plate to be processed is located directly above the deformable mold.

[0020] The energy converter on the surface of the laser-impacted bipolar plate is used to vaporize and ionize the absorption layer and form a shock wave. The pressure of the shock wave causes the bipolar plate to undergo cold plastic deformation. Through point-by-point impact and orderly impact point distribution, the forming of complex-shaped workpieces can be achieved.

[0021] Synchronous stamping: At the instant when the laser-treated area softens due to heat, the die head of the deformable mold provides support force, forcing the bipolar plate to undergo plastic deformation along the die head contour to form a flow channel; during this process, the bipolar plate and the laser generator move synchronously to ensure the integrity of the flow channel.

[0022] Furthermore, for bipolar plate processing of serpentine and interdigitated flow channels, the deformable mold can be flipped up and down to complete the continuous processing of the bipolar plate flow channel.

[0023] The beneficial effects of this invention are as follows:

[0024] (1) This invention, by setting a synchronous drive system on the laser generator, can achieve synchronization between the laser pulse and the movement of the bipolar plate, thereby improving the accuracy and quality of laser stamping. The encoder provides real-time feedback on the movement speed of the bipolar plate, dynamically adjusting the laser pulse frequency to ensure pulse spacing error and flow channel edge roughness during high-speed processing. Combined with the sub-micron level positioning accuracy of the 180° rotatable mold, it solves the problems of dimensional attenuation and clamping error in traditional processing, meeting the stringent requirements of micro fuel cells for flow channel size and surface quality.

[0025] (2) In this invention, the special mold on the workbench is equipped with a clamping mechanism that can rotate 180°, which can greatly save the manufacturing of the mold, directly control the movement of the mold, eliminate the need for whole plate manufacturing, facilitate the processing of bipolar plates, eliminate the need for multiple clamping, and improve processing efficiency.

[0026] (3) In this invention, the bipolar plate is supported by two guide rail columns. The bipolar plate is connected to the synchronous driver through an X / Y direction sliding mechanism, realizing synchronous movement of the bipolar plate processing and the laser generator, as well as continuous processing of the flow channel. The processing time on one side is shortened compared with traditional machining. No auxiliary support is required for regular flow channels, reducing post-processing time and improving material utilization.

[0027] (4) Significant advantages in low cost and green manufacturing: Rapid changeover is achieved through modular fixtures and parametric programming, reducing mold costs and maintenance costs. There is no waste liquid discharge during the processing, improving material utilization and reducing energy consumption compared to traditional processes, which is in line with the trend of environmentally friendly production.

[0028] (5) Through technological innovation, this invention achieves multi-dimensional breakthroughs in precision, efficiency, cost, adaptability and intelligence, providing an efficient and reliable solution for the large-scale production of core components of micro fuel cells. Attached Figure Description

[0029] Figure 1 This is a simplified diagram of a laser stamping device for processing the flow channels on the surface of a bipolar plate in a micro fuel cell.

[0030] Figure 2 This is a structural diagram of the rotating mechanism;

[0031] Figure 3 This is a structural diagram of the machining clamping mechanism;

[0032] Figure 4 This is a schematic diagram of a bipolar plate structure with parallel flow channels;

[0033] Figure 5 This is a schematic diagram of the mold corresponding to the parallel flow channel;

[0034] Figure 6 This is a schematic diagram of a bipolar plate structure in a serpentine flow channel;

[0035] Figure 7 This is a schematic diagram of the upper die head corresponding to the serpentine flow channel;

[0036] Figure 8 This is a schematic diagram of the lower die head corresponding to the serpentine flow channel;

[0037] Figure 9 This is a schematic diagram of a bipolar plate structure with an interdigitated flow channel;

[0038] Figure 10 This is a schematic diagram of the mold corresponding to the interdigitated runner;

[0039] Figure 11 This is a diagram showing the effect of laser stamping.

[0040] In the diagram, 1. Laser generator, 2. Laser beam, 3. Lens, 4. Reflector, 5. Beam shaping unit, 6. Energy converter, 7. Bipolar plate, 8. Screw, 9. Upper pressure plate, 10. Threaded hole, 11. Lower pressure plate, 12. Y-axis slider, 13. Y-axis guide rail, 14. X-axis slider, 15. X-axis guide rail, 16. Cylindrical pin, 17. Mold clamping plate, 18. Deformable mold, 19. Support plate, 20. Rotating mechanism, 21. Worktable, 22. Rotating robotic arm, 23. Motor, 24. Guide rail column, 25. Lower pressure plate moving slider, 26. Lower pressure plate moving guide rail. Detailed Implementation

[0041] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but the scope of protection of the present invention is not limited thereto.

[0042] like Figure 1 As shown, the laser stamping processing device for the surface flow channel of the micro fuel cell bipolar plate of the present invention includes a worktable 21, a clamping system, a stamping forming system and a synchronous drive system. The clamping system includes a mold clamping mechanism and a processing clamping mechanism.

[0043] Above the worktable 21 is a mold clamping mechanism that can rotate and flip 180° in a plane. Above the worktable 21 are two processing clamping mechanisms that can control the bipolar plate 7 to move in the X and Y directions. The mold clamping mechanism and the processing clamping mechanism work together to ensure that the bipolar plate 7 is located directly above the deformable mold 18 during processing.

[0044] The mold clamping mechanism includes two mold clamping plates 17, a support plate 19, and a rotating mechanism 20; as shown Figure 2 As shown, the rotating mechanism 20 includes two rotating robotic arms 22 and a motor 23. The motor 23 is mounted on the worktable 21, and the output shaft of the motor 23 is connected to the two rotating robotic arms 22. The two rotating robotic arms 23 are located on the front and rear sides of the mold clamping plate 17. The support plate 19 is fixed on the worktable 21, and a protrusion is provided on the upper part of the support plate 19. The mold clamping plate 17 has grooves on both the upper and lower parts, and the groove on the lower part of the mold clamping plate 17 cooperates with the protrusion on the support plate 19 to clamp the mold clamping plate 17 on the upper part of the support plate 19. The deformable mold 18 is placed between the two mold clamping plates 17 and fixed by the cylindrical pin 16.

[0045] The deformable mold 18 has upper and lower surface shapes designed according to the different flow channel requirements of the bipolar plate. For example... Figure 5 As shown, for parallel flow channels ( Figure 4 The mold only has an "S"-shaped upper die head, and the lower surface has no shape; for example... Figure 7 , 8 As shown, for serpentine flow channels ( Figure 6The mold has "S"-shaped die heads on both its upper and lower surfaces, and these die heads are symmetrically distributed when viewed on the same plane to ensure consistent processing shape after flipping. Figure 10 As shown, for interdigitated flow channels ( Figure 9 The mold has a "T" shaped die head only on the upper surface, and no shape on the lower surface.

[0046] like Figure 3 As shown, the guide column 24 of the machining clamping mechanism is connected to the worktable 21 via an X-direction sliding mechanism and a Y-direction sliding mechanism. The X-direction sliding mechanism includes an X-direction slider guide rail 15 and an X-direction slider 14. The X-direction guide rail 15 is fixed on the worktable 21, and the X-direction slider 14 is fixedly connected to the lower surface of the guide column 24, and the X-direction slider 14 can slide on the X-direction guide rail 15. The Y-direction sliding mechanism includes a Y-direction guide rail 13 and a Y-direction slider 12. The Y-direction guide rail 13 is fixed on the guide column 24, and the Y-direction slider 12 is fixedly connected to the upper pressure plate 9, and the Y-direction slider 12 can slide on the Y-direction guide rail 13. Both the upper pressure plate 9 and the lower pressure plate 11 are provided with threaded holes 10, and the two are connected by screws 8. A lower pressure plate moving slider 25 is provided on one side of the lower pressure plate 11 near the upper pressure plate 9. The lower pressure plate moving slider 25 slides on the lower pressure plate moving guide rail 26, which is set on the upper pressure plate 9.

[0047] A stamping system is provided above the deformable mold 18. The stamping system includes a laser generator 1, a lens 3, a reflector 4, and a beam shaping unit 5. The centers of the laser generator 1, lens 3, and reflector 4 are on the same horizontal line, and the centers of reflector 4 and beam shaping unit 5 are on the same vertical line. Figure 1 As shown, the laser beam 2 is emitted parallel to the laser generator 1, continues forward through the lens 3, is deflected downwards by the reflector 4, and finally converges onto the surface of the bipolar plate 7 to be processed by the beam shaping unit 5. The laser impacts the energy converter 6 (composed of a transparent constraint layer and an opaque absorption layer) on the workpiece surface, causing partial vaporization and ionization of the absorption layer to form a shock wave. The pressure of the shock wave causes cold plastic deformation of the plate. Complex shapes are formed through point-by-point impact and an orderly distribution of impact points. The laser stamping effect is as follows: Figure 11 As shown.

[0048] The laser generator 1 is equipped with a synchronous drive system, which is used to drive the laser pulses emitted by the laser generator 1 to move synchronously with the bipolar plate 7.

[0049] The synchronous drive system consists of a controller, encoders, and drive motors. Each of the X-direction slider 14 and Y-direction slider 12 is controlled by a drive motor. Encoders are mounted on the drive motors to detect their operating status (speed) in real time, indirectly reflecting the moving speed of the bipolar plate 7, and feeding the signal back to the controller. The controller controls the operation of the drive motors based on the encoder signals, thereby driving the X-direction slider 14 and Y-direction slider 12. Simultaneously, the controller synchronously adjusts the pulse frequency and output power of the laser generator 1 based on the movement of the bipolar plate 7, achieving precise matching between the laser pulse and the movement of the bipolar plate. The drive motors, as power actuators, receive commands from the controller and directly drive the sliders. The entire system forms a closed-loop synchronous control: the encoder detects the motion parameters of the drive motors → the controller processes the signals and generates commands → the drive motors execute the motion, and the controller synchronously adjusts the laser parameters → the encoder feeds back the actual state → the controller performs dynamic compensation.

[0050] First, the processing mold and workpiece are clamped and fixed. The processing mold is fixed on the mold clamping mechanism, and the bipolar plate to be processed is fixed on the processing clamping mechanism. The starting position of the flow field forming is placed at the starting section of the mold and laser-coordinated forming, so that the bipolar plate 7 to be processed is exactly above the mold. Next, based on the three-dimensional model of the bipolar plate flow channel pre-designed in the controller, the pulsed laser stamping precision forming process is adopted. After laser pretreatment, the pulsed laser scans along the flow channel trajectory and uses the energy conversion body 6 (composed of a transparent constraint layer and an opaque absorption layer) on the surface of the workpiece to vaporize and ionize the absorption layer and form a shock wave. The pressure of the shock wave causes the bipolar plate 7 to undergo cold plastic deformation. The forming of complex-shaped workpieces is achieved through point-by-point impact and orderly impact point distribution. Then, the pre-preparation stage of synchronous co-processing stamping is carried out. The code parameters of the synchronous driver are set to ensure that the laser and the processing clamping mechanism move synchronously to complete the flow channel processing. Next comes synchronous stamping. At the moment when the laser-treated area softens, the die head provides support force, forcing the metal sheet to undergo plastic deformation along the die head contour to form a flow channel. During this process, the bipolar plate 7 moves synchronously with the laser generator 1 to ensure the integrity of the flow channel.

[0051] The processing methods and parameters used for different flow channels are different. Different molds should be selected according to the processing of parallel flow channels, serpentine flow channels, and interdigitated flow channels, and different parameter settings should be adopted, including the movement or flipping of the mold after processing, as described in the processing flow design below.

[0052] Pre-treatment stage: Based on the forming shape of the flow channel on the surface of the bipolar plate 7, a deformable mold 18 that matches it is selected. For bipolar plates 7 made of materials such as stainless steel and titanium alloy, surface cleaning is required.

[0053] Positioning and clamping: Fix the deformable mold 18 on the mold clamping mechanism, fix the bipolar plate 7 to be processed on the processing clamping mechanism, and place the starting position of the flow field forming at the starting section of the mold and laser forming, so that the bipolar plate to be processed is exactly above the mold; then operate according to the above technical solution. The mold operation method is different for different flow field processing.

[0054] Mold Rotation: For machining serpentine runners, an "S"-shaped mold is used, with symmetrical upper and lower end faces. Continuous machining of the runner can be completed by rotating a single mold vertically. During machining of the upper mold head, such as... Figure 7 As shown, the upper surfaces A, B, and C of the mold correspond to the bipolar plate processing positions a, b, and c, respectively. The laser generator 1 performs sequential stamping. After processing on one side, the Y-direction slider 12 moves upward along the Y-direction guide rail 13, and the mold is flipped via the rotation mechanism 20. Then, the Y-direction slider 12 moves downward along the Y-direction guide rail 13, positioning the lower surface of the mold at the processing position directly below the bipolar plate. The upper and lower mold heads are used in conjunction. Figure 8 As shown, the lower surfaces D, E, and F of the mold correspond to the bipolar plate processing positions d, e, and f, respectively. The laser generator 1 performs stamping sequentially to complete one cycle of processing. The above operation is repeated until the entire serpentine flow channel is stamped and formed. For the processing of parallel flow channels, a mold with an "S"-shaped upper die head can be used. The processing of parallel flow channels is relatively simpler than that of serpentine flow channels. Only the upper die head is "S"-shaped and the processing is performed sequentially. After processing one flow channel, the X-direction slider 14 moves back and forth on the X-direction guide rail 15, and the laser generator 1 returns to the starting position. The above operation is repeated to complete the processing and forming of the flow field of the entire parallel flow channel. For the processing of interdigitated flow channels, a "T" shaped mold is used. When processing interdigitated flow channels, only one side of the bipolar plate needs to be processed first, and then the other side is processed. That is, the mold does not need to be changed when processing one side; it only needs to be fixed in position. After processing one flow channel, the X-direction slider 14 moves on the X-direction guide rail 15, and the laser generator 1 returns to the starting position. Repeating the above operation completes the processing of one side of the flow channel. Then, the mold is rotated 180° back and forth, changing from the original "T" shape to an inverted "T" shape. Repeating the above operation completes the formation of the entire flow field.

[0055] Post-processing: Once the bipolar plate surface flow channel processing meets the preset requirements, the laser generator 1 stops working, and the processing clamping mechanism stops driving the bipolar plate 7 to move. Release the processing clamping mechanism and remove the processed bipolar plate 7. Perform ultrasonic cleaning to remove surface melt and burrs from the flow channel edges; no additional polishing is required. Turn off the power to all systems of the device, clean and perform routine maintenance on the device, and prepare it for the next processing cycle.

[0056] The embodiments described above are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments. Any obvious improvements, substitutions or modifications that can be made by those skilled in the art without departing from the essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A laser stamping apparatus for the surface flow channels of a bipolar plate in a micro fuel cell, characterized in that, include: The clamping system includes a mold clamping mechanism and a processing clamping mechanism. The mold clamping mechanism includes two mold clamping plates (17), a support plate (19), and a rotating mechanism (20). The support plate (19) is fixed on the worktable (21), and the upper part of the support plate (19) cooperates with the mold clamping plate (17). The flipping action of the mold clamping plate (17) is realized by the rotating mechanism (20). A deformable mold (18) is fixed between the two mold clamping plates (17). The upper and lower surface shapes of the deformable mold (18) are designed according to the different flow channels required by the bipolar plate. The processing clamping mechanism includes a guide rail column (24), and the guide rail column (24) is connected to the worktable (21) through an X-direction sliding mechanism and a Y-direction sliding mechanism, respectively. The end of the Y-direction sliding mechanism is provided with a double pressure plate for clamping the bipolar plate (7). The stamping forming system includes a laser generator (1), a lens (3), a reflector (4), and a beam shaping unit (5). The centers of the laser generator (1), the lens (3), and the reflector (4) are on the same horizontal line, and the centers of the reflector (4) and the beam shaping unit (5) are on the same vertical line. The laser beam from the beam shaping unit (5) is focused onto the surface of the bipolar plate (7) to be processed. A synchronous drive system is used to drive the laser pulses emitted by the laser generator (1) to move synchronously with the bipolar plate (7).

2. The laser stamping apparatus for the surface flow channels of the bipolar plate of a micro fuel cell according to claim 1, characterized in that, The rotating mechanism (20) includes two rotating robotic arms (22) and a motor (23). The motor (23) is mounted on the workbench (21), and the output shaft of the motor (23) is connected to the two rotating robotic arms (22). The two rotating robotic arms (23) are located on the front and rear sides of the mold clamping plate (17).

3. The laser stamping apparatus for the surface flow channels of the bipolar plate of a micro fuel cell according to claim 1, characterized in that, For bipolar plates with parallel flow channels, only the upper surface of the deformable mold (18) has an "S" shaped die head.

4. The laser stamping apparatus for the surface flow channels of the bipolar plate of a micro fuel cell according to claim 1, characterized in that, For bipolar plates with serpentine flow channels, the upper and lower surfaces of the deformable mold (18) have "S"-shaped mold heads, and the upper and lower mold heads are symmetrically distributed on the same plane.

5. The laser stamping apparatus for the surface flow channels of the bipolar plate of a micro fuel cell according to claim 1, characterized in that, For bipolar plates with interdigitated flow channels, the deformable mold (18) has a "T" shaped die head only on the upper surface.

6. The laser stamping apparatus for the surface flow channels of the bipolar plate of a micro fuel cell according to claim 1, characterized in that, The double pressure plate used to tighten the bipolar plate (7) includes an upper pressure plate (9) and a lower pressure plate (11), which are connected by screws, and the lower pressure plate (11) can move relative to the upper pressure plate (9).

7. The laser stamping apparatus for the surface flow channels of the bipolar plate of a micro fuel cell according to claim 6, characterized in that, The lower pressure plate (7) moves relative to the upper pressure plate (9) via a sliding mechanism.

8. The laser stamping apparatus for the surface flow channel of the bipolar plate of a micro fuel cell according to claim 1, characterized in that, The synchronous drive system consists of a controller, an encoder and a drive motor. The X-direction sliding mechanism and the Y-direction sliding mechanism are each driven by a drive motor. The drive motors are each equipped with an encoder. The controller controls the drive motor to run according to the encoder signal. The controller also adjusts the pulse frequency and output power of the laser generator (1) synchronously according to the movement of the bipolar plate (7) to achieve matching between the laser pulse and the movement of the bipolar plate.

9. A method for laser stamping processing apparatus for surface flow channels of bipolar plates in micro fuel cells according to any one of claims 1-8, characterized in that: The deformable mold (18) is fixed on the mold clamping mechanism, and the bipolar plate (7) to be processed is fixed on the processing clamping mechanism so that the bipolar plate (7) to be processed is located directly above the deformable mold (18). The energy converter (6) on the surface of the bipolar plate (7) is used to vaporize and ionize the absorption layer and form a shock wave. The pressure of the shock wave causes the plate of the bipolar plate (7) to undergo cold plastic deformation. Through point-by-point impact and orderly impact point distribution, the forming of complex shaped workpieces is achieved. Synchronous stamping: At the moment when the laser action area softens, the die head of the deformable mold (18) provides support force, forcing the bipolar plate (7) to undergo plastic deformation along the die head contour to form a flow channel; during this process, the bipolar plate (7) and the laser generator (1) move synchronously to ensure the integrity of the flow channel.

10. The method according to claim 9, characterized in that, By machining the bipolar plate (7) with serpentine flow channels and interdigitated flow channels, the deformable mold (18) can be flipped up and down to complete the continuous machining of the bipolar plate (7) flow channels.

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