Metal graphite composite bipolar plate forming device

Abstract

The invention provides a metal graphite composite bipolar plate forming device. The metal graphite composite bipolar plate forming device solves the technical problem that according to an existing bipolar plate forming device, low-plasticity materials such as graphite and flexible graphite paper are prone to being locally fractured during stamping forming. The forming device is provided with a plurality of male die assemblies. The male die assembly is provided with a block punch, the block punch is provided with a miniature protrusion and a first blind hole, the first blind hole is provided with a hole edge, and a first spring is installed in the first blind hole. A plurality of longitudinal through holes are formed in the upper die plate from left to right at intervals, and each longitudinal through hole is provided with one male die assembly. A blocking punch is connected in the longitudinal through hole in a sliding manner; the base plate covers the longitudinal through hole, a first blocking part is arranged at the top end of the pressing rod, a rod body of the pressing rod penetrates through the second spring and the base plate to enter the longitudinal through hole, and a second blocking part is arranged at the bottom end of the pressing rod, connected with the first spring and clamped in the hole edge; the lengths of rod bodies of the pressing rods exposed out of the base plate are distributed in a stepped descending manner from left to right; the method can be widely applied to the technical field of fuel cell bipolar plate precision manufacturing.

Description

Technical Field

[0001] The present application relates to the technical field of precision manufacturing of bipolar plates for fuel cells, and in particular to a metal-graphite composite bipolar plate forming device. Background Art

[0002] Metal bipolar plates are one of the core components of fuel cells, and their main functions are to conduct current, distribute gas, and support the cell stack structure. Metal bipolar plates are increasingly used in fuel cells because metal materials have excellent electrical conductivity, thermal conductivity, and high mechanical strength. However, since metal bipolar plates need to have complex flow channel structures processed on their surfaces to meet the requirements of gas distribution and water management, their manufacturing process is difficult. However, due to the acidic electrolytes and high temperature conditions in the operating environment of fuel cells, metal bipolar plates are prone to corrosion and passivation, affecting their performance and service life. Therefore, it is particularly important to improve the molding process and structural design of metal bipolar plates.

[0003] The stamping process is the most commonly used method in the manufacture of metal bipolar plates. Its principle is to use a stamping die and a press to apply pressure to the metal sheet to cause it to undergo plastic deformation and form the required flow channel structure and geometric shape. The stamping process has become one of the preferred processes for bipolar plate processing due to its high production efficiency, low cost, and suitability for mass production. However, in the stamping process, multiple microchannels are formed at the same time. The formation of the microchannels requires the workpiece itself to undergo plastic deformation. Strain concentration usually occurs in the lower fillet, resulting in severe thickness thinning, which requires the material to have good plasticity. However, materials such as graphite and flexible graphite paper have almost no plasticity themselves, which can easily lead to local rupture during the stamping process. Summary of the invention

[0004] The purpose of the present invention is to solve the deficiencies of the above-mentioned technology and provide a metal-graphite composite bipolar plate forming device to ensure that materials such as graphite and flexible graphite paper are intact during the preparation of the metal-graphite composite bipolar plate.

[0005] To this end, the present invention provides a metal-graphite composite bipolar plate forming device, the forming device is provided with an upper mold mechanism and a lower mold mechanism, the upper mold mechanism is provided with an upper mold bottom plate and an upper mold plate, and micro-protrusions are provided below the lower surface of the upper mold plate; the lower mold mechanism is provided with a lower mold bottom plate and a lower mold plate, and micro-grooves are provided on the upper surface of the lower bottom plate. The upper mold plate and the lower mold plate are arranged opposite to each other up and down, and after the mold is closed, the micro-protrusions and micro-grooves are matched to form a micro-channel.

[0006] The forming device is also provided with a stepped punch mechanism, which is provided with a pad and multiple punch assemblies; each punch assembly is provided with a segmented punch, a pressure rod, a first spring, and a second spring; a micro-protrusion is provided at the lower part of the segmented punch, and a first blind hole opening upward is provided at the upper part of the segmented punch; a hole edge extending inward is provided at the opening of the first blind hole, and a first spring is installed in the first blind hole.

[0007] The upper template is provided with a plurality of longitudinal through holes spaced in sequence from left to right, and a punch assembly is installed corresponding to each longitudinal through hole; the segmented punch is arranged in the longitudinal through hole, and the two are slidably connected; the pad covers the longitudinal through hole, and the top end of the pressure rod is provided with a first stopper, and the rod body of the pressure rod passes downward through the second spring and the pad in turn and then enters the longitudinal through hole, and the bottom end of the pressure rod is provided with a second stopper, and the second stopper is connected to the first spring. Under the action of the elastic force of the first spring, the second stopper is movably engaged in the edge of the hole.

[0008] The length of the rod body of each pressure rod located between the first stop portion and the pad is distributed in a step-like decreasing manner from left to right.

[0009] Preferably, the first spring is a force transmission spring.

[0010] Preferably, the second spring is a compression spring.

[0011] Preferably, the forming device is further provided with a first guide column, both ends of which are respectively connected to the upper mold bottom plate and the lower mold bottom plate, and the first guide column is respectively slidably connected through the upper mold bottom plate, the upper mold plate and the lower mold plate.

[0012] Preferably, the longitudinal through hole of the upper template is a square hole.

[0013] Preferably, the forming device is also provided with a limiting support device, the support device is provided with a limiting support rod, a second blind hole opening downward is opened on the lower surface of the upper template, a third spring is installed in the second blind hole, the bottom end of the limiting support rod is installed on the lower template, and the top end of the limiting support rod is connected to the third spring.

[0014] Preferably, a third stopper is provided at the top end of the position-limiting support rod, the third stopper is connected to the third spring, and the third stopper is slidably connected to the inner wall of the second blind hole.

[0015] Preferably, the third spring is a limit spring.

[0016] The beneficial effects of the present invention are as follows: the present invention provides a metal-graphite composite bipolar plate forming device, which is provided with a stepped punch mechanism, the stepped punch mechanism is provided with a pad and a plurality of punch assemblies, each punch assembly is provided with a pressure rod, and the lengths of the rod bodies of the plurality of pressure rods exposed from the pad are distributed in a stepped manner from left to right. During the hydraulic press mold closing process, the plurality of punch assemblies are successively lowered in the longitudinal through hole to form the microchannels of the plate workpiece in a sequence from left to right. In the whole process, the forming of the microchannels of the metal-graphite composite bipolar plate depends on the flow of materials such as graphite and flexible graphite paper from the right to the left, rather than the overall stamping deformation of the prior art, which effectively avoids the rupture of materials such as graphite and flexible graphite paper, and ensures that materials such as graphite and flexible graphite paper are intact. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0018] Figure 1 It is a structural schematic diagram of a partial cross-sectional view of the present invention in a mold opening state;

[0019] Figure 2 for Figure 1 A schematic diagram of the structure of the enlarged view of part A shown;

[0020] Figure 3 for Figure 1 A schematic structural diagram of an enlarged view of part B shown;

[0021] Figure 4 It is a structural schematic diagram of a partial cross-sectional view of action 1 in the mold closing process of the present invention;

[0022] Figure 5 It is a structural schematic diagram of a partial cross-sectional view of action 2 in the mold closing process of the present invention;

[0023] Figure 6 It is a structural schematic diagram of a partial cross-sectional view of the present invention in a mold closing state.

[0024] Markings in the figure: 1. Upper die base plate, 2. Upper template, 3. Micro protrusion, 4. Lower die base plate, 5. Lower template, 6. Micro groove, 7. Pad, 8. Punch assembly, 9. Block punch, 10. Pressure rod, 11. First spring, 12. Second spring, 13. First blind hole, 14. Hole edge, 15. Longitudinal through hole, 16. First stop, 17. Second stop, 18. First guide column, 19. Limit support device, 20. Limit support rod, 21. Second blind hole, 22. Third spring, 23. Third stop, 24. Plate workpiece. DETAILED DESCRIPTION

[0025] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application clearer, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application. The methods used in the present invention are conventional methods unless otherwise specified; the raw materials and devices used are conventional commercial products unless otherwise specified.

[0026] Depend on Figure 1 , Figure 2 As shown, the present invention provides a metal-graphite composite bipolar plate forming device, the forming device is provided with an upper mold mechanism and a lower mold mechanism, the upper mold mechanism is provided with an upper mold base plate 1 and an upper mold plate 2, and a micro-protrusion 3 is provided below the lower surface of the upper mold plate 2; the lower mold mechanism is provided with a lower mold base plate 4 and a lower mold plate 5, and a micro-groove 6 is provided on the upper surface of the lower base plate, the upper mold plate 2 and the lower mold plate 5 are arranged opposite to each other up and down, and after the mold is closed, the micro-protrusion 3 and the micro-groove 6 are matched to form a micro-channel.

[0027] The forming device is also provided with a stepped punch mechanism, which is provided with a pad 7 and multiple punch assemblies 8; each punch assembly 8 is provided with a segmented punch 9, a pressure rod 10, a first spring 11, and a second spring 12. The lower part of the segmented punch 9 is provided with a micro-protrusion 3, and the upper part of the segmented punch 9 is provided with a first blind hole 13 opening upward, and the opening of the first blind hole 13 is provided with a hole edge 14 extending inward, and a first spring 11 is installed in the first blind hole 13.

[0028] The upper template 2 is provided with a plurality of longitudinal through holes 15 spaced apart from each other from left to right, and a punch assembly 8 is installed corresponding to each longitudinal through hole 15; the segmented punch 9 is arranged in the longitudinal through hole 15, and the two are slidably connected; the pad 7 covers the longitudinal through hole 15, and the top end of the pressure rod 10 is provided with a first stopper 16, and the rod body of the pressure rod 10 passes downward through the second spring 12 and the pad 7 and then enters the longitudinal through hole 15, and the bottom end of the pressure rod 10 is provided with a second stopper 17, and the second stopper 17 is connected to the first spring 11. Under the action of the elastic force of the first spring 11, the second stopper 17 is movably engaged in the hole edge 14.

[0029] The lengths of the rods of the plurality of pressure rods 10 exposed from the backing plate 7 are distributed in a step-like decreasing manner from left to right.

[0030] When the present invention is used, the upper die bottom plate 1 and the lower die bottom plate 4 are fixed on the hydraulic press respectively, wherein the upper die bottom plate 1 is fixedly connected to the cross beam of the hydraulic press, and the lower die bottom plate 4 is fixed on the base of the hydraulic press, and the downward pressure of the upper die bottom plate 1 is controlled by controlling the displacement of the cross beam of the hydraulic press; first, a sheet workpiece 24 to be formed is placed in the forming area on the lower template 5, and the sheet workpiece 24 is the existing metal-graphite composite sheet to be formed.

[0031] The specific forming process is as follows: the hydraulic press is started, the upper die bottom plate 1 moves downward, first touching the first punch assembly 8 on the left, pushing the pressure rod 10 of the punch assembly 8 downward, so that the first spring 11 and the second spring 12 are compressed, driving the segment punch 9 to move downward, and the micro protrusion 3 at the bottom of the segment punch 9 matches the micro groove 6 located directly below it, forming a micro channel of the plate workpiece 24 located on the far left, as shown in FIG. Figure 1 , Figure 2 , Figure 4 shown.

[0032] As the upper die bottom plate 1 continues to move downward, it touches the second punch assembly 8 on the left side, compresses the second pressure rod 10 on the left side to move downward, compresses the first spring 11 and the second spring 12, drives the segment punch 9 to move downward, and makes the sheet workpiece 24 flow to the left side to form the second microchannel on the left side, as shown in FIG. Figure 4 , Figure 5 shown.

[0033] As the upper die bottom plate 1 continues to move downward, the divided punches 9 of the five male die assemblies 8 form the microchannels from left to right. Finally, the entire upper die plate 2 is driven to move downward to complete the final mold closing process, and the metal-graphite composite bipolar plate is prepared. Figure 6 shown.

[0034] During the entire process, the formation of the metal-graphite composite bipolar plate microchannel relies on the flow of materials such as graphite and flexible graphite paper from the right to the left, rather than the overall stamping deformation of the existing technology, which effectively avoids the rupture of materials such as graphite and flexible graphite paper, ensuring that materials such as graphite and flexible graphite paper are intact.

[0035] In some embodiments, Figure 2 As shown, the first spring 11 is preferably a force transmission spring that maintains a constant elastic force within a corresponding stroke.

[0036] In some embodiments, Figure 2 As shown, the second spring 12 is preferably a compression spring for resisting compression force or storing energy.

[0037] In some embodiments, Figure 1 As shown, the forming device is preferably also provided with a first guide column 18 for guiding and positioning, the two ends of the first guide column 18 are respectively connected to the upper mold base plate 1 and the lower mold base plate 4, and the first guide column 18 is respectively slidably connected through the upper mold base plate 1, the upper mold plate 2, and the lower mold plate 5.

[0038] In some embodiments, Figure 2 As shown, the longitudinal through hole 15 of the upper template 2 is preferably a square hole with good stability.

[0039] In some embodiments, Figure 1 , Figure 3 As shown, the forming device is preferably further provided with a limit support device 19, the support device is provided with a limit support rod 20, the lower surface of the upper template 2 is provided with a second blind hole 21 opening downward, a third spring 22 is installed in the second blind hole 21, the bottom end of the limit support rod 20 is installed on the lower template 5, and the top end of the limit support rod 20 is connected to the third spring 22. When the forming device is molded, the third spring 22 is compressed, the top end of the limit support rod 20 gradually enters the second blind hole 21, the third spring 22 is continuously compressed, and the mold is finally closed; when the forming device is molded, the elastic force of the third spring 22 is released, pushing the upper template 2 to rise, so that the upper template 2 and the lower template 5 are separated.

[0040] In some embodiments, preferably, a third stopper 23 is provided at the top end of the limiting support rod 20, the third stopper 23 is connected to the third spring 22, and the third stopper 23 is slidably connected to the inner wall of the second blind hole 21, so that the upper template 2 can rise or fall more stably and reliably.

[0041] In some embodiments, the third spring 22 is preferably a limit spring, which uses the elasticity of the spring to limit the range of the moving part.

[0042] It should be noted that:

[0043] (1) During the process of opening or closing the mold of the hydraulic press, under the action of the spring force of the first spring 11 and the second spring 12, the punch assembly 8 rises or falls in the longitudinal through hole 15; intuitively, the pressure rod 10 drives the segment punch 9 to rise or fall.

[0044] (2) During the mold opening process after the hydraulic press mold closing, the working state of the present invention is as follows Figure 6 , Figure 5 , Figure 4 , Figure 1 order.

[0045] (3) By Figure 1As shown, the lengths of the rods of the plurality of pressure rods 10 exposed from the pad 7 are distributed in a stepped descending manner from left to right, preferably in an arithmetic progression, and the lengths of the rods of two adjacent pressure rods 10 exposed from the pad 7 differ by the height of the microchannel. The operator can adjust the length of the pressure rod 10 according to actual conditions.

[0046] In the description of the present invention, it should be understood that the terms "left", "right", "up", "down", "top", "bottom", "front", "back", "inside", "outside", "back", "middle", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention. It should be noted that in the above-mentioned embodiments, the "first", "second" and "third" do not represent an absolute distinction in structure and / or function, nor do they represent a sequential execution order, but are merely for the convenience of description.

[0047] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A metal-graphite composite bipolar plate forming device, the forming device is provided with an upper mold mechanism and a lower mold mechanism, the upper mold mechanism is provided with an upper mold base plate (1) and an upper mold plate (2), and a micro protrusion (3) is provided below the lower surface of the upper mold plate (2); the lower mold mechanism is provided with a lower mold base plate (4) and a lower mold plate (5), and a micro groove (6) is provided on the upper surface of the lower mold plate, the upper mold plate (2) and the lower mold plate (5) are arranged opposite to each other up and down, and after the mold is closed, the micro protrusion (3) and the micro groove (6) are matched to form a micro channel, characterized in that The forming device is also provided with a stepped punch mechanism, the stepped punch mechanism is provided with a pad (7) and a plurality of punch assemblies (8); each of the punch assemblies (8) is provided with a segmented punch (9), a pressure rod (10), a first spring (11), and a second spring (12); a micro protrusion (3) is provided at the lower part of the segmented punch (9); a first blind hole (13) opening upward is provided at the upper part of the segmented punch (9); a hole edge (14) extending inward is provided at the opening of the first blind hole (13); and a first spring (11) is installed in the first blind hole (13); The upper template (2) is provided with a plurality of longitudinal through holes (15) spaced from left to right, and each longitudinal through hole (15) is provided with a corresponding punch assembly (8); the segmented punch (9) is arranged in the longitudinal through hole (15), and the two are slidably connected; the pad (7) covers the longitudinal through hole (15), and the top end of the pressure rod (10) is provided with a first stopper (16), and the rod body of the pressure rod (10) passes through the second spring (12) and the pad (7) downwards and then enters the longitudinal through hole (15), and the bottom end of the pressure rod (10) is provided with a second stopper (17), and the second stopper (17) is connected to the first spring (11), and under the action of the elastic force of the first spring (11), the second stopper (17) is movably engaged in the hole edge (14); The lengths of the rod bodies of the plurality of pressure rods (10) exposed from the pad (7) are distributed in a step-like decreasing manner from left to right.

2. The metal-graphite composite bipolar plate forming device according to claim 1, characterized in that: The first spring (11) is a force transmission spring.

3. The metal-graphite composite bipolar plate forming device according to claim 1, characterized in that: The second spring (12) is a compression spring.

4. The metal-graphite composite bipolar plate forming device according to claim 1, characterized in that: The forming device is also provided with a first guide column (18), the two ends of which are respectively connected to the upper mold base plate (1) and the lower mold base plate (4), and the first guide column (18) is respectively slidably connected and passes through the upper mold base plate (1), the upper mold plate (2), and the lower mold plate (5).

5. The metal-graphite composite bipolar plate forming device according to claim 1, characterized in that: The longitudinal through hole (15) of the upper template (2) is a square hole.

6. The metal-graphite composite bipolar plate forming device according to claim 1, characterized in that: The forming device is also provided with a limit support device (19), the support device is provided with a limit support rod (20), the lower surface of the upper template (2) is provided with a second blind hole (21) opening downward, a third spring (22) is installed in the second blind hole (21), the bottom end of the limit support rod (20) is installed on the lower template (5), and the top end of the limit support rod (20) is connected to the third spring (22).

7. The metal-graphite composite bipolar plate forming device according to claim 6, characterized in that: A third stopper (23) is provided at the top end of the position-limiting support rod (20), the third stopper (23) is connected to the third spring (22), and the third stopper (23) is slidably connected to the inner wall of the second blind hole (21).

8. The metal-graphite composite bipolar plate forming device according to claim 6, characterized in that: The third spring (22) is a limit spring.

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