Modularized stamping die for optimizing flow field structure of titanium bipolar plate

Abstract

The invention belongs to the technical field of proton exchange membrane fuel cell bipolar plate forming, and discloses a modular stamping die for titanium bipolar plate flow field structure optimization, which comprises a forming male die core and a forming female die core, a plurality of groups of raised first local size flow fields are engraved on the forming male die core; the plurality of groups of first local size flow fields are the same or different in shape, the same or different in size and the same or different in spacing; and concave second local size flow fields corresponding to the first local size flow fields one by one are engraved on the forming female die core, so that the forming male die core is embedded in the forming female die core. The modularized stamping die for optimizing the flow field structure of the titanium bipolar plate can replace a low-precision finite element simulation technology, flow field structure parameters with better forming results are matched and combined, the structure optimization of the flow field of the titanium bipolar plate is really realized, and the modularized stamping die is simple in structure, low in machining difficulty, higher in interchangeability and suitable for popularization and application. And the die opening test cost of the precision stamping die is greatly reduced.

Description

Technical Field

[0001] The invention relates to the technical field of proton exchange membrane fuel cell bipolar plate forming, and in particular to a modular stamping die for optimizing the flow field structure of a titanium bipolar plate. Background Art

[0002] As an important medium for converting hydrogen energy into electrical energy, proton exchange membrane fuel cells have broad application prospects in the fields of transportation, clean power generation, and portable mobile power sources. The fuel cell stack is the core of the fuel cell system, and the bipolar plate is a key component of the fuel cell stack, accounting for 60% to 80% of the total weight of the fuel cell stack and 20% to 40% of the cost. At present, the materials used for commercial metal bipolar plates are mainly titanium and stainless steel. Comprehensively comparing the metal's specific strength and corrosion resistance, titanium has obvious advantages over stainless steel. At the same time, the surface-modified titanium bipolar plate is also more stable, which can greatly improve the energy efficiency of fuel cells.

[0003] The flow field structure of the bipolar plate determines the effective reaction area ratio of the fuel cell, the uniformity of the reaction gas distribution, and the circulation cooling effect. As the requirements for the use of fuel cells in various fields continue to increase, the bipolar plate is gradually tending to be ultra-thin (usually ≤0.1mm), the flow channel is more complex, and the structure is more precise, which also puts higher requirements on the flow field design and optimization of the bipolar plate.

[0004] The main forming method for metal bipolar plates is precision stamping, and the cost of preparing the full-size flow field mold is extremely expensive. Taking a small-sized full-size test plate with a plate size of 180mm×90mm and a flow field area size of 140mm×70mm as an example, the cost of preparing the precision stamping mold is as high as 400,000 to 600,000 yuan. The cost of preparing the precision stamping mold for full-size plates with industrial application specifications often reaches several million yuan. Therefore, the flow field design and optimization of conventional metal bipolar plates usually adopt finite element simulation.

[0005] However, as a typical close-packed hexagonal structure metal, titanium has significant anisotropic mechanical properties, making it difficult to process. At the same time, there are large differences in thickness and surface size of titanium plates used for bipolar plates, resulting in serious size effects during the forming process. Conventional material constitutive models are no longer applicable, resulting in extremely low accuracy of finite element simulation deformation results, and unable to provide accurate guidance for the optimization of its flow field structure. Therefore, the optimization of the flow field structure of titanium bipolar plates is an important scientific issue that needs to be broken through to promote the industrial production and application of titanium bipolar plates for fuel cells.

[0006] In order to solve the above technical problems, a person skilled in the art provides a metal bipolar plate stamping combined die. For example, the prior art CN109465336A provides a metal bipolar plate stamping combined die for a proton exchange membrane fuel cell. The die adopts a combined stamping punch and die. However, the flow channel shape involved is relatively simple, mainly parallel straight flow channels and wavy flow channels, which is difficult to meet the requirements of the current increasingly complex flow field structure. At the same time, the die of the prior art CN109465336A is a multi-module combined die, which mainly forms a full-size flow field by combining multiple modules for stamping and forming of the full-size flow field. According to the measured results of the formed full-size flow field, the flow field is optimized by replacing individual modules. However, after replacing individual modules, it is easy to cause the overall structure of the overall flow field to change, which in turn affects the test of the overall structure of the flow field, which is not conducive to guiding the actual flow field optimization. Summary of the invention

[0007] In order to solve the above technical problems, the present invention provides a modular stamping die for optimizing the flow field structure of a titanium bipolar plate, which aims to adopt a modular stamping test die with a relatively simple structure, low preparation cost and high interchangeability to reduce the trial production cost of a full-size stamping die. At the same time, guided by measured data, the flow field structure parameters with better forming results are matched and combined to truly achieve the structural optimization of the flow field of the titanium bipolar plate.

[0008] The modular stamping die for optimizing the flow field structure of a titanium bipolar plate of the present invention is realized by the following technical solutions:

[0009] A modular stamping die for optimizing the flow field structure of a titanium bipolar plate is used for stamping forming experiments on titanium bipolar plates for proton exchange membrane fuel cells. The die comprises a forming core assembly, which is mounted on a fixed die frame and can be disassembled so that the forming core assembly of the invention can be replaced. The die has low processing difficulty and strong interchangeability, which greatly reduces the die opening test cost of the precision stamping die.

[0010] It should be noted that the forming mold core assembly includes a forming convex mold core and a forming concave mold core. Among them, the forming convex mold core of the present invention is engraved with several groups of raised and mutually independent first local size flow fields. By setting several groups of first local size flow fields independently of each other, it is ensured that the several groups of first local size flow fields do not affect each other during the forming process, and the local size flow field can reflect all characteristic parameters of the corresponding full-size flow field. In addition, in the present invention, the shapes of several groups of the first local size flow fields are the same or different, the sizes of several groups of the first local size flow fields are the same or different, and the spacing between each two adjacent first local size flow fields is the same or different. After the corresponding forming convex mold core and the forming concave mold core are combined, a forming test is carried out, and the flow field structure parameters with better forming results are matched and combined to achieve the structural optimization of the titanium bipolar plate flow field, thereby achieving the effect of optimizing the titanium bipolar plate flow field structure.

[0011] The forming die core of the present invention is engraved with several groups of concave and independent second local size flow fields, and the structures of several groups of the second local size flow fields are arranged one by one corresponding to the structures of the corresponding first local size flow fields, so that the forming convex die core can be embedded in the forming die core.

[0012] In the present invention, each group of the first local size flow fields includes a plurality of first flow channels, and the first flow channels are parallel straight flow channels, periodic wave flow channels or other special shape flow channels; wherein the other special shape flow channels include variable size bionic structure flow channels.

[0013] In some preferred embodiments of the present invention, the shapes of several first flow channels are the same or different, the sizes of several first flow channels are the same or different, the spacing between every two adjacent first flow channels is the same or different, and a forming test is carried out after combining the corresponding forming punch core with the forming die core, and the flow field structure parameters with better forming results are matched and combined to achieve structural optimization of the titanium bipolar plate flow field, thereby achieving the effect of optimizing the flow field structure of the titanium bipolar plate.

[0014] In some preferred embodiments of the present invention, the characteristic parameters in the cross-sectional profile of each of the first flow channels include a titanium bipolar plate thickness γ, and the titanium bipolar plate thickness γ is 0.05 mm to 1 mm.

[0015] In some preferred embodiments of the present invention, the characteristic parameters in the cross-sectional profile of each of the first flow channels further include a flow channel width W, and the flow channel width W is ≥ 0.05 mm.

[0016] In some preferred embodiments of the present invention, the characteristic parameters in the cross-sectional profile of each of the first flow channels further include a flow channel depth h, and the flow channel depth h is 0.05 mm to 1 mm.

[0017] In some preferred embodiments of the present invention, the characteristic parameters in the cross-sectional profile of each of the first flow channels further include a flow channel opening angle θ, and the flow channel opening angle θ is 0 to 90°.

[0018] In some preferred embodiments of the present invention, the characteristic parameters in the cross-sectional profile of each of the first flow channels further include a flow channel angle β, and the flow channel angle β is 30° to 150°.

[0019] In some preferred embodiments of the present invention, the characteristic parameters in the cross-sectional profile of each of the first flow channels also include a flow channel ridge width S, a flow channel inner fillet r and a flow channel outer fillet R, and the flow channel ridge width S, the flow channel inner fillet r and the flow channel outer fillet R are matched accordingly according to the electrode plate thickness, the flow channel depth and the flow channel width.

[0020] In some preferred embodiments of the present invention, when the adopted flow channel result is a periodic wave flow channel, the characteristic parameters in the cross-sectional profile of each of the first flow channels also include a flow channel period length CL and a flow channel wave crest and trough angle ɑ.

[0021] It should also be noted that, corresponding to the first local size flow field, each group of the second local size flow field also includes a corresponding number of second flow channels, and the structures of the second flow channels are arranged one-to-one with the corresponding first flow channels. That is, the second flow channels are parallel straight flow channels, periodic wave flow channels or other special shape flow channels.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] The modular stamping die for optimizing the flow field structure of the titanium bipolar plate of the present invention includes a forming core assembly, which is installed on a fixed mold frame and can be disassembled so that the forming core assembly of the present invention can be replaced. The processing difficulty is low, and the forming core assembly has strong interchangeability, which greatly reduces the mold opening test cost of the precision stamping die. The forming die core assembly of the present invention comprises a forming convex die core and a forming concave die core, the forming convex die core is engraved with a plurality of groups of convex and mutually independent first local size flow fields, the forming concave die core is engraved with a plurality of groups of concave and mutually independent second local size flow fields, the structure of the second local size flow field is arranged one-to-one with the structure of the corresponding first local size flow field, so that the forming convex die core is embedded in the forming concave die core, so that the modular stamping die for optimizing the flow field structure of the titanium bipolar plate of the present invention can replace the low-precision finite element simulation technology, and the corresponding forming convex die core is combined with the forming concave die core to carry out a forming test, and the flow field structure parameters with better forming results are matched and combined, so as to truly realize the structural optimization of the titanium bipolar plate flow field. At the same time, compared with the full-size stamping die, the replaceable local flow field die core has a simple overall structure, low processing difficulty, strong interchangeability, and greatly reduces the mold opening test cost of the precision stamping die, and the die can also compare and analyze the forming performance of different batches of titanium bipolar plate materials, which has a considerable guiding role in optimizing the preparation process of the material.

[0024] The metal bipolar plate stamping assembly die provided by the prior art CN109465336A has not been specifically designed for the forming characteristics of the titanium bipolar plate, and the flow channel parameters and specific ranges that need to be optimized have not been announced, so the reference and guiding significance for the optimization of the flow field structure of the titanium bipolar plate is relatively low. However, the present invention adopts a modular stamping test die with a relatively simple structure, low preparation cost and high interchangeability, and replaces the finite element simulation technology with poor accuracy with measured data as a guide, and matches and combines the flow field structure parameters with better forming results, while effectively realizing the optimized design of the flow channel structure of the titanium bipolar plate, significantly reducing the trial production cost of the full-size stamping die, which plays an important role in the preparation of high-efficiency proton exchange membrane fuel cells and is conducive to promoting the further development and utilization of hydrogen energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a structural schematic diagram of the cross-sectional profile of the first flow channel of the present invention.

[0026] Figure 2 It is a schematic structural diagram of the flow channel corner in the cross-sectional profile of the first flow channel of the present invention.

[0027] Figure 3 Schematic diagram of the cross-sectional profile of a periodic wave flow channel.

[0028] Figure 4It is a structural schematic diagram of the forming punch core of the present invention.

[0029] Figure 5 It is a structural schematic diagram of the forming die core of the present invention.

[0030] Figure 6 This is a physical photo of the forming punch core used in Example 2 of the present invention.

[0031] Figure 7 This is a physical photo of the forming die core used in Example 2 of the present invention.

[0032] Figure 8 It is a schematic structural diagram of six groups of first local size flow fields etched on the forming punch core used in Example 2 of the present invention, Figure 8 In the figure, (I) is a structural schematic diagram of the first group of first local size flow fields, (II) is a structural schematic diagram of the second group of first local size flow fields, (III) is a structural schematic diagram of the third group of first local size flow fields, (IV) is a structural schematic diagram of the fourth group of first local size flow fields, (V) is a structural schematic diagram of the fifth group of first local size flow fields, and (VI) is a structural schematic diagram of the sixth group of first local size flow fields.

[0033] Fig. 9 The first group of first local size flow fields, the second group of first local size flow fields and the third group of first local size flow fields are along Figure 8 Schematic diagram of the flow channel cross-section structure along line AA.

[0034] Fig.10 for Fig. 9 Partially enlarged images of C, D and E in the middle.

[0035] Fig.11 The fourth group of first local size flow fields, the fifth group of first local size flow fields and the sixth group of first local size flow fields are along Figure 8 Schematic diagram of the flow channel cross-section structure of line BB in FIG.

[0036] Fig.12 for Fig.11 Partially enlarged images of F, G and H in the middle.

[0037] Fig.13 This is a photo of the morphology of a batch of TA1 titanium alloy bipolar plates after stamping test.

[0038] Fig.14 These are morphology photos of two batches of TA1 titanium alloy bipolar plates after stamping tests. DETAILED DESCRIPTION

[0039] The technical solutions in the embodiments of the present invention will be described clearly and completely below.

[0040] Example 1

[0041] This embodiment provides a modular stamping die for optimizing the flow field structure of titanium bipolar plates used in stamping forming experiments of proton exchange membrane fuel cells.

[0042] The modular stamping die for optimizing the flow field structure of the titanium bipolar plate of this embodiment includes a forming core assembly, which is installed on a fixed mold frame and can be disassembled so that the forming core assembly of the present invention can be replaced. It has low processing difficulty and strong interchangeability, which greatly reduces the mold opening test cost of the precision stamping die.

[0043] In this embodiment, the forming mold core assembly includes a forming convex mold core 1 and a forming concave mold core 2. Among them, the forming convex mold core 1 is engraved with a plurality of mutually independent first local size flow fields 3, and the plurality of first local size flow fields 3 are set independently of each other to ensure that the plurality of first local size flow fields 3 do not affect each other during the forming process, and the local size flow field can reflect all characteristic parameters of the corresponding full size flow field, so that the forming mold core assembly of the present invention can meet the preparation requirements of complex flow field structures.

[0044] In this embodiment, the shapes of several groups of the first local size flow fields 3 are the same or different, the sizes of several groups of the first local size flow fields 3 are the same or different, and the spacing between every two adjacent first local size flow fields 3 is the same or different. By combining the corresponding forming punch core and the forming die core, a forming test is carried out, and the flow field structure parameters with better forming results are matched and combined, so as to truly achieve the structural optimization of the titanium bipolar plate flow field and truly achieve the effect of optimizing the flow field structure of the titanium bipolar plate.

[0045] In this embodiment, several groups of independent second local size flow fields 4 are engraved on the forming die core 2, and the structures of several groups of the second local size flow fields 4 are arranged one by one corresponding to the structures of the corresponding first local size flow fields 3, so that the forming convex die core 1 and the forming die core 2 can be interlocked with each other.

[0046] In a preferred embodiment of the present invention, each group of the first local size flow fields 3 includes a plurality of first flow channels 301, and the shapes of the plurality of first flow channels 301 are the same or different, the sizes of the plurality of first flow channels 301 are the same or different, and the spacing between every two adjacent first flow channels 301 is the same or different. A forming test is carried out by combining the corresponding forming punch core with the forming die core, and the flow field structure parameters with better forming results are matched and combined to achieve structural optimization of the titanium bipolar plate flow field, thereby achieving structural optimization of the titanium bipolar plate flow field.

[0047] In a preferred embodiment of the present invention, each of the first flow channels 301 can be selected accordingly according to actual needs. For example, each of the first flow channels 301 can be selected from any one of a parallel straight flow channel, a periodic wave flow channel and other special shape flow channels; wherein the other special shape flow channels include variable size bionic structure flow channels.

[0048] In a preferred embodiment of the present invention, please refer to Figure 1 The characteristic parameters in the cross-sectional profile of each of the first flow channels 301 include the titanium bipolar plate thickness γ, the flow channel width W, the flow channel depth h, the flow channel opening angle θ and the flow channel turning angle β, wherein the titanium bipolar plate thickness γ is 0.05 mm to 1 mm, the flow channel width W ≥ 0.05 mm, the flow channel depth h is 0.05 mm to 1 mm, the flow channel opening angle θ is 0 to 90°, and the flow channel turning angle β is 30° to 150°.

[0049] In a preferred embodiment of the present invention, please refer to Figure 1 and Figure 2 The characteristic parameters in the cross-sectional profile of each of the first flow channels 301 also include a flow channel ridge width S, a flow channel inner fillet r and a flow channel outer fillet R. The flow channel ridge width S, the flow channel inner fillet r and the flow channel outer fillet R are matched accordingly according to the plate thickness, the flow channel depth and the flow channel width.

[0050] In some preferred embodiments of the present invention, please refer to Figure 3 When the adopted flow channel result is a periodic wave flow channel, the characteristic parameters in the cross-sectional profile of each of the first flow channels 301 also include the flow channel period length CL and the flow channel wave crest and trough angle ɑ.

[0051] It should also be noted that, corresponding to the first local size flow field 3, each group of the second local size flow field 4 also includes a plurality of second flow channels 401, and the plurality of second flow channels 401 are arranged in one-to-one correspondence with the structure of the corresponding first flow channel 301. That is, each of the second flow channels 401 is also selected from any one of parallel straight flow channels, periodic wave flow channels and other special shape flow channels.

[0052] Example 2

[0053] The forming die core assembly of the modular stamping die for optimizing the flow field structure of the titanium bipolar plate used in this embodiment is as follows: Figure 4 The forming punch core 1 shown and Figure 5 The forming die core 2 is composed of the forming die core 2 shown in the figure, and the physical diagram of the forming die core 1 in this embodiment is as shown in the figure Figure 6 As shown, the actual picture of the forming die core 2 is as follows Figure 7 shown.

[0054] Depend on Figure 4 and Figure 6 It can be seen that six groups of first local size flow fields 3 are etched on the forming punch core 1 of the present invention, and the six groups of first local size flow fields 3 are independent of each other.

[0055] Depend on Figure 5 and Figure 7 It can be seen that the forming die core 2 of the present invention is etched with six groups of second local size flow fields 4, the six groups of second local size flow fields 4 are independent of each other, and the six groups of second local size flow fields 4 correspond one-to-one with their corresponding first local size flow fields 3 and match each other.

[0056] The structures of the six groups of first local size flow fields 3 etched on the forming punch core 1 of this embodiment are as follows: Figure 8 As shown, Figure 8 In the figure, (I) is a structural schematic diagram of the first group of first local size flow fields, (II) is a structural schematic diagram of the second group of first local size flow fields, (III) is a structural schematic diagram of the third group of first local size flow fields, (IV) is a structural schematic diagram of the fourth group of first local size flow fields, (V) is a structural schematic diagram of the fifth group of first local size flow fields, and (VI) is a structural schematic diagram of the sixth group of first local size flow fields.

[0057] In order to facilitate the description of the flow channel structure, the present invention is respectively Figure 8 The AA line and the BB line in FIG. 3 show the flow channel cross section of each group of the first local size flow field 3, and are respectively as follows: Figures 9 to 12 shown.

[0058] in, Fig. 9 The first group of first local size flow fields, the second group of first local size flow fields and the third group of first local size flow fields are along Figure 8 Schematic diagram of the flow channel cross-section structure of line AA in the figure. Fig.10 for Fig. 9 Partially enlarged images of C, D and E in the middle.

[0059] Fig.11 The fourth group of first local size flow fields, the fifth group of first local size flow fields and the sixth group of first local size flow fields are along Figure 8 Schematic diagram of the flow channel cross-section structure of line BB in the figure. Fig.12 for Fig.11 Partially enlarged images of F, G and H in the middle.

[0060] Depend on Figure 8 Figure (I) in the figure, and Figure 7 and Figure 8It can be seen that the first group of the first local size flow field consists of 10 equally spaced periodic wavy flow channels, with a channel depth of 0.5 mm, a channel width of 0.8 mm, a channel spacing of 1.6 mm, a channel inner fillet of 0.2 mm, a channel outer fillet of 0.3 mm, a channel opening angle of 40°, a channel period length of 16 mm, and a channel wave crest and trough angle of 150°.

[0061] Depend on Figure 8 Figure (II) in the figure, and Figure 7 and Figure 8 It can be seen that the second group of first local size flow fields consists of 10 equally spaced periodic wavy flow channels, with a channel depth of 0.4 mm, a channel width of 0.8 mm, a channel spacing of 1.6 mm, a channel inner fillet of 0.15 mm, a channel outer fillet of 0.25 mm, a channel opening angle of 40°, a channel period length of 16 mm, and a channel wave crest and trough angle of 150°.

[0062] Depend on Figure 8 Figure (III) in the figure, and Figure 7 and Figure 8 It can be seen that the first local size flow field of the third group is composed of 10 equally spaced periodic wavy flow channels, with a channel depth of 0.3 mm, a channel width of 0.8 mm, a channel spacing of 1.6 mm, a channel inner fillet of 0.1 mm, a channel outer fillet of 0.2 mm, a channel opening angle of 40°, a channel period length of 16 mm, and a channel wave crest and trough angle of 150°.

[0063] Depend on Figure 8 Figure (IV) in the figure, and Fig. 9 and Fig.10 It can be seen that the first local size flow field of the fourth group is composed of 10 equally spaced periodic wavy flow channels, with a channel depth of 0.3 mm, a channel width of 0.5 mm, a channel spacing of 1 mm, a channel inner fillet of 0.1 mm, a channel outer fillet of 0.2 mm, a channel opening angle of 40°, a channel period length of 16 mm, and a channel wave crest and trough angle of 150°.

[0064] Depend on Figure 8 Figure (V) in the figure, and Fig. 9 and Fig.10 It can be seen that the first local size flow field of the fifth group is composed of 10 equally spaced periodic wavy flow channels, with a channel depth of 0.4 mm, a channel width of 0.8 mm, a channel spacing of 1.6 mm, a channel inner fillet of 0.15 mm, a channel outer fillet of 0.25 mm, a channel opening angle of 30°, a channel period length of 16 mm, and a channel wave crest and trough angle of 150°.

[0065] Depend on Figure 8 Figure (VI) in the figure, and Fig.11 and Fig.12It can be seen that the sixth group of first local size flow fields consists of 20 parallel straight channels with different corners, where each parallel straight channel has a depth of 0.3 mm, a channel width of 0.8 mm, a channel spacing of 1.6 mm, a channel inner fillet of 0.1 mm, a channel outer fillet of 0.2 mm, a channel opening angle of 40°, and a channel corner range of 90 to 120°.

[0066] The present invention combines the above Figure 6 and Figure 7 The punch core 1 and the concave core 2 shown in the figure are interlocked with each other, and two batches of TA1 titanium alloy bipolar plates with a thickness of 0.1 mm are subjected to stamping forming tests, and the plates after the test are as follows Fig.13 and Fig.14 shown.

[0067] Fig.13 This is a photo of the morphology of a batch of TA1 titanium alloy bipolar plates after stamping test. Fig.14 These are morphology photos of two batches of TA1 titanium alloy bipolar plates after stamping tests.

[0068] Depend on Fig.13 It can be seen from the test structure that the flow channels with a depth of 0.5 mm in the first group of local flow fields and the flow channels with an opening angle of 30° in the fifth group of local flow fields both experienced serious cracking, while the degree of cracking in the flow channels with a depth of 0.4 mm in the second group of local flow fields was relatively low.

[0069] Compared to Fig.13 In terms of Fig.14 It can be seen from the test structure that the local flow field with a depth of 0.5mm and the flow channel with an opening angle of 30° of the second batch of bipolar plates experienced a lower degree of cracking.

[0070] By comparison Fig.13 and Fig.14 From the test results, it can be seen that the above two batches of titanium bipolar plates are more sensitive to the flow channel depth and the flow channel opening angle. The flow field design of the first batch of plates should control the flow channel depth to be less than 0.4mm and the flow channel opening angle to be greater than 30°. The flow field design of the second batch of plates should control the flow channel depth to be less than 0.5mm and the flow channel opening angle to be greater than 30°.

[0071] Further comparison of the two batches of plate stamping test results shows that the first batch of plate stamping cracking phenomenon is more serious, indicating that its stamping forming performance is relatively poor. Therefore, the preparation process of the first batch of plate materials can be adjusted and optimized accordingly according to the differences in the preparation process of materials between batches.

[0072] Obviously, the above embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

Claims

1. A modular stamping die for optimizing the flow field structure of titanium bipolar plates, used for stamping forming experiments of proton exchange membrane fuel cells titanium bipolar plates, characterized in that: It includes a forming die core assembly which is installed on a fixed die frame and can be disassembled and replaced; The forming die core assembly comprises a forming male die core (1) and a forming female die core (2); The forming convex die core (1) is engraved with a plurality of groups of raised and mutually independent first local size flow fields (3); the shapes of the plurality of groups of the first local size flow fields (3) are the same or different, the sizes of the plurality of groups of the first local size flow fields (3) are the same or different, and the spacing between each two adjacent first local size flow fields (3) is the same or different; The forming die core (2) is engraved with a plurality of groups of concave and mutually independent second local size flow fields (4); the structures of the plurality of groups of the second local size flow fields (4) are arranged in one-to-one correspondence with the structures of the first local size flow fields (3) corresponding thereto, so that the forming convex die core (1) is embedded in the forming die core (2); Wherein, each group of the first local size flow fields (3) includes a plurality of first flow channels (301); The first flow channel (301) is a parallel straight flow channel, a periodic wave flow channel or a flow channel of other special shapes; the other flow channels of special shapes include flow channels of variable-size bionic structures.

2. The modular stamping die for optimizing the flow field structure of titanium bipolar plates according to claim 1, characterized in that: The shapes of a plurality of the first flow channels (301) are the same or different, the sizes of a plurality of the first flow channels (301) are the same or different, and the distance between every two adjacent first flow channels (301) is the same or different.

3. The modular stamping die for optimizing the flow field structure of titanium bipolar plates according to claim 1, characterized in that: The characteristic parameters in the cross-sectional profile of each of the first flow channels (301) include a titanium bipolar plate thickness γ, and the titanium bipolar plate thickness γ is 0.05 mm to 1 mm.

4. The modular stamping die for optimizing the flow field structure of titanium bipolar plates according to claim 1, characterized in that: The characteristic parameters in the cross-sectional profile of each of the first flow channels (301) further include a flow channel width W, and the flow channel width W is ≥ 0.05 mm.

5. The modular stamping die for optimizing the flow field structure of titanium bipolar plates according to claim 1, characterized in that: The characteristic parameters in the cross-sectional profile of each of the first flow channels (301) further include a flow channel depth h, and the flow channel depth h is in the range of 0.05 mm to 1 mm.

6. The modular stamping die for optimizing the flow field structure of titanium bipolar plates according to claim 1, characterized in that: The characteristic parameters in the cross-sectional profile of each of the first flow channels (301) further include a flow channel opening angle θ, and the flow channel opening angle θ is 0 to 90°.

7. The modular stamping die for optimizing the flow field structure of titanium bipolar plates according to claim 1, characterized in that: The characteristic parameters in the cross-sectional profile of each of the first flow channels (301) further include a flow channel corner β, and the flow channel corner β is 30° to 150°.

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