Composite forming die for metal bipolar plate

Abstract

A composite forming die for a metal bipolar plate is used for processing a metal plate with the thickness of 0.03-0.1 mm under the driving of a press and comprises a die pressing mechanism, a punching mechanism and a blanking mechanism. Wherein the mould pressing mechanism is used for carrying out mould pressing forming on a plate, the punching mechanism is used for punching on the plate to form inlet and outlet holes of hydrogen, air (oxygen) and cooling water at two ends of the bipolar plate, and the blanking mechanism is used for separating the bipolar plate formed by processing the plate from waste materials removed by cutting. The three actions of punching, blanking and forming can be completed on one station when the press moves downwards and returns for one time, so that the production efficiency of the bipolar plate can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of metal processing, and in particular to a composite forming die for a metal bipolar plate. Background Art

[0002] A hydrogen fuel cell is a power generation device that converts chemical energy into electrical energy through the electrochemical reaction of hydrogen and oxygen, and has many advantages such as zero carbon emissions, high efficiency, low noise, and low temperature resistance. A bipolar plate is one of the core components of a hydrogen fuel cell, and undertakes functions such as current conduction, gas distribution, heat management, and mechanical support. Its performance directly affects the power density, durability, and cost of the fuel cell stack. Metal bipolar plates have become the mainstream choice for vehicle-mounted fuel cells due to their advantages such as high electrical conductivity, light weight, and easy processing. The materials of metal bipolar plates are commonly materials such as aluminum, titanium, and stainless steel, and the thickness is commonly 0.075 - 0.1 mm.

[0003] The bipolar plate is composed of four functional areas: a pipeline area, a distribution area, a flow field area, and a sealing area. The main function of the pipeline area is to form supply channels for hydrogen, air, and coolant; the distribution area is a transition area where the reaction gas enters the flow field area from the common pipeline area, and the flow rate of the coolant entering each flow channel of the cooling flow field is uniform to meet the requirement of uniform heat dissipation; the flow field area corresponds to the active area of the fuel cell and is an important area participating in the reaction, which determines the flow states of hydrogen, oxygen, and water in the flow field; the main function of the sealing area is to use a seal to cooperate with the battery components after the stack is assembled to achieve the seal between the bipolar plate and the proton exchange membrane assembly.

[0004] The application of metal bipolar plates requires a stamping process to achieve the production of high-precision flow channels with a large area of flow fields, and the surface has high corrosion resistance and low interfacial contact resistance. Designing and manufacturing high-precision stamping dies is the key to the efficient production of metal bipolar plates. Therefore, there is an urgent need for a composite forming die for metal bipolar plates that can improve the production efficiency of bipolar plates. Summary of the Invention

[0005] In view of the above problems in the prior art, the present application provides a composite forming die for a metal bipolar plate, which can improve the production efficiency of the bipolar plate.

[0006] The present application provides a composite forming die for a metal bipolar plate, which is used to press a metal sheet into a bipolar plate, and the thickness t of the sheet is 0.03 - 0.1 mm; it includes:

[0007] A molding mechanism, the molding mechanism having a first mold and a second mold, a first forming portion being provided on a surface of the first mold facing the second mold, a second forming portion being provided on a surface of the second mold facing the first mold, and after the first mold and the second mold are closed in the mold closing direction, a cavity is formed between the first forming portion and the second forming portion, and the sheet material between the first mold and the second mold is stamped and formed;

[0008] A punching mechanism, the punching mechanism having a punching punch and a punching die, the punching punch extending along the mold closing direction and being disposed through the first mold, the length exposed from the first forming portion being equal to t; the punching die is disposed on the second forming portion and at a position corresponding to the punching punch; the edge height of the punching die is 5t, and after closing the mold, the depth of the punching punch entering the punching die is greater than 5t;

[0009] A blanking mechanism, the blanking mechanism having a blanking die, a receiving hole being provided on the blanking die, the opening of the receiving hole facing the second mold, the first mold being disposed in the receiving hole, the size of the receiving hole being adapted to the size of the second mold, the second mold pressing the sheet material into the receiving hole and closing the mold with the first mold, and the depth of the second mold extending into the receiving hole being equal to 10t.

[0010] With the above structure, by providing a punching mechanism on the molding mechanism, the length of the punching punch exposed from the first forming portion is equal to t, that is, equal to the thickness of the sheet material. Thus, before the first mold and the second mold are closed to perform molding on the sheet material, the punching punch can first punch the positions of the hydrogen, air (oxygen), and cooling water inlet and outlet holes at both ends of the bipolar plate. At the same time, by making the length of the punching punch exposed from the first forming portion equal to the thickness of the sheet material, it can be ensured that the punching punch can completely penetrate the sheet material, thereby improving the punching effect.

[0011] In addition, by providing a blanking mechanism, the size of the receiving hole is adapted to the size of the second mold, so that when the second mold presses the sheet material into the receiving hole and closes the mold with the first mold, the edge of the sheet material can be cut by the shearing force between the blanking die and the second mold. At the same time, by making the depth of the second mold extending into the receiving hole be 10t, it can be ensured that the waste material cut from the edge of the sheet material can be completely separated from the sheet material, that is, when the first mold and the second mold are closed to press the sheet material into a bipolar plate, the separation from the edge waste material is achieved simultaneously.

[0012] Thus, the metal bipolar plate composite forming die in the present application can simultaneously perform punching, blanking, and molding on the sheet material through one pressing action. Thereby, the production steps of the bipolar plate can be reduced, the production rhythm can be improved, and the production efficiency of the bipolar plate can be improved.

[0013] In some embodiments, the molding mechanism further includes: a first mounting plate, on which the blanking female die is fixedly mounted; a first spring, which is arranged on the side of the first die facing away from the opening of the accommodating hole, and pushes the first die to move towards the second die, so that the first forming part is flush with the opening of the accommodating hole. When the depth of the second die extending into the accommodating hole is equal to 10t, the first die abuts against the first mounting plate.

[0014] With the above structure, by arranging the first spring, the first spring pushes the first die to move towards the second die, so that the first die can become a floating die. Thus, when the second die and the first die are closed, the plate can be clamped into the accommodating hole, thereby improving the stability of the plate, and further improving the stability when trimming the plate, so as to improve the trimming effect and the molding effect.

[0015] In some embodiments, a first abutting surface is arranged on the inner peripheral surface of the accommodating hole, and the first abutting surface faces the first mounting plate; on the outer peripheral surface of the first die, a second abutting surface is arranged at a position corresponding to the first abutting surface. When the first forming part is flush with the opening of the accommodating hole, the first abutting surface abuts against the second abutting surface.

[0016] With the above structure, through the abutting cooperation between the first abutting surface and the second abutting surface, it can prevent the first die from exposing from the opening of the accommodating hole under the push of the first spring, thereby avoiding the first die from pushing up the plate from the blanking female die, so as to improve the stability of the plate.

[0017] At the same time, by avoiding the first die from pushing up the plate from the blanking female die, the plate is placed on the blanking female die, so that it is convenient for the following blank holder to clamp the edge of the plate on the blanking female die, and further improve the blank holding effect.

[0018] In some embodiments, after the second die extends into the accommodating hole, the gap between the second die and the accommodating hole is 0.1t.

[0019] With the above structure, by setting the gap between the second die and the accommodating hole to 0.1t, the stability of the second die when pressing the plate can be improved, and further the forming effect when forming the bipolar plate can be improved.

[0020] In some embodiments, the molding mechanism further includes: a second mounting plate, the second mold is fixed on the second mounting plate, and the second mounting plate is used to connect to a press and move along the mold closing direction under the drive of the press; a blank holder, the blank holder is sleeved on the second mold and is slidably connected to the second mold along the mold closing direction; a second spring, the second spring is mounted on the second mounting plate and pushes the blank holder to expose from the second mold toward the first mold side.

[0021] With the above structure, by setting the blank holder and the second spring, the blank holder is exposed from the second mold toward the first mold side, so that before the second mold moves toward the first mold for mold closing, the blank holder can first press and fix the edge of the sheet on the blanking female die. Thus, the stability of the sheet can be improved, and further the stability during trimming and die pressing forming of the sheet can be improved to enhance the forming effect of the bipolar plate.

[0022] In some embodiments, the second spring is an adjustable pressure spring, and the pressure of the second spring is set to 65 kN.

[0023] With the above structure, by setting the second spring as an adjustable pressure spring, the pressure of the blank holder on the edge of the sheet can be adjusted as needed. Thus, not only can the adaptation range be improved, but also by setting an appropriate blank holding force, defects such as wrinkling or cracking of the sheet during the forming process can be prevented. In addition, by setting the pressure of the second spring to 65 kN, the pressing and fixing effect of the blank holder on the edge of the sheet can be improved.

[0024] In some embodiments, the blanking mechanism further includes: a waste ejector rod, the waste ejector rod is arranged in the punching female die; a third spring, the third spring is arranged in the second mold and drives the end of the waste ejector rod to extend to the edge end of the punching edge of the punching female die.

[0025] With the above structure, by setting the waste ejector rod and the third spring, after the bipolar plate is formed, the third spring can drive the waste ejector rod to eject the waste punched by the punching punch and the punching female die on the sheet from the punching female die, so that automatic blanking can be realized, which is convenient for the user to clean.

[0026] In some embodiments, the third spring is an adjustable pressure spring.

[0027] With the above structure, by setting the third spring as an adjustable pressure spring, the thrust when the punching punch pushes the waste out of the punching female die can be adjusted, so that the blanking effect can be improved.

[0028] In some embodiments, the cavity is bent to form a plurality of alternately arranged hydrogen-oxygen flow channel portions and cooling water flow channel portions. The hydrogen-oxygen flow channel portions are recessed and formed in the direction towards the second mold, and the cooling water flow channel portions are recessed and formed in the direction towards the first mold. The hydrogen-oxygen flow channel portions and the cooling water flow channel portions are serpentine channels.

[0029] With the above structure, after the first mold and the second mold are closed to form the cavity, the sheet can form hydrogen-oxygen flow channels and cooling water flow channels in a serpentine channel shape on both side surfaces along with the cavity.

[0030] In some embodiments, the thickness of the cavity is t, the bottom width of the hydrogen-oxygen flow channel portion is 4t, and the bottom width of the cooling water flow channel portion is 12t.

[0031] With the above structure, by making the thickness of the cavity be t, the bottom width of the hydrogen-oxygen flow channel portion be 4t, and the bottom width of the cooling water flow channel portion be 12t, the forming effect of the bipolar plate can be improved.

[0032] These and other aspects of the present invention will become more readily apparent in the following description of the (several) embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The following further illustrates the various features of the present invention and the relationships between the various features with reference to the accompanying drawings. The drawings are all exemplary. Some features are not shown in actual proportion, and in some drawings, conventional features in the field related to the present application that are not necessary for the present application may be omitted, or features that are not necessary for the present application may be shown additionally. The combination of the various features shown in the drawings is not intended to limit the present application. Additionally, throughout this specification, the content referred to by the same reference numerals is also the same. The specific description of the drawings is as follows:

[0034] Figure 1 It is a schematic structural diagram of a metal bipolar plate composite forming mold in the present application;

[0035] Figure 2 is Figure 1 a top view of the corresponding part of the first mold in

[0036] Figure 3 is Figure 1 a partial enlarged view of the cavity formed by the first mold and the second mold in

[0037] Figure 4 is Figure 1 a partial enlarged view of the first forming portion of the first mold in

[0038] Figure 5 is Figure 1 a partial enlarged view of the second forming portion of the second mold in

[0039] Figure 6 Flow chart of processing bipolar plates using a metal bipolar plate composite forming die

[0040] Description of reference numerals in the drawings

[0041] 10 Metal bipolar plate composite forming die; 100 Molding mechanism; 110 First die; 111 First forming part; 112 Second abutting surface; 120 Second die; 121 Second forming part; 130 First mounting plate; 140 First spring; 150 Second mounting plate; 160 Blank holder; 170 Second spring; 200 Punching mechanism; 210 Punching punch; 220 Punching die; 300 Blanking mechanism; 310 Blanking die; 311 Accommodating hole; 312 First abutting surface; 320 Locating pin; 330 Scrap ejector rod; 340 Third spring; 20 Cavity Detailed implementation manners

[0042] The terms "first", "second", "third", etc. or terms such as module A, module B, module C, etc. in the description and claims are only used to distinguish similar objects and do not represent a specific order for the objects. Understandably, the specific order or sequence can be interchanged when permitted, so that the embodiments of the present application described herein can be implemented in an order other than that illustrated or described herein

[0043] In the following description, the reference numerals representing steps, such as S110, S120, etc., do not necessarily mean that these steps will be executed in this order. The order of the front and rear steps can be interchanged when permitted, or they can be executed simultaneously

[0044] The term "comprising" used in the description and claims should not be construed as being limited to the content listed thereafter; it does not exclude other elements or steps. Therefore, it should be interpreted as specifying the presence of the described features, wholes, steps or components, but does not exclude the presence or addition of one or more other features, wholes, steps or components and their groups. Therefore, the expression "equipment including device A and B" should not be limited to the equipment composed only of components A and B

[0045] The "one embodiment" or "embodiment" mentioned in this specification means that the specific features, structures or characteristics described in combination with this embodiment are included in at least one embodiment of the present invention. Therefore, the phrases "in one embodiment" or "in an embodiment" appearing throughout this specification do not necessarily refer to the same embodiment, but may refer to the same embodiment. In addition, in one or more embodiments, the specific features, structures or characteristics can be combined in any appropriate manner, as will be apparent to those of ordinary skill in the art from this disclosure

[0046] Next, with reference to the drawings, an exemplary description of the specific structure of the metal bipolar plate composite forming die 10 in the present application will be given

[0047] This application provides a metal bipolar plate composite forming die 10 for pressing a metal sheet into a bipolar plate, and the thickness t of the sheet is 0.03 - 0.1 mm. The metal bipolar plate composite forming die 10 includes a molding mechanism 100, a punching mechanism 200, and a blanking mechanism 300. Among them, the molding mechanism 100 has a first die 110 and a second die 120. A first forming portion 111 is provided on the surface of the first die 110 facing the second die 120, and a second forming portion 121 is provided on the surface of the second die 120 facing the first die 110. After the first die 110 and the second die 120 are closed in the die - closing direction, a cavity 20 is formed between the first forming portion 111 and the second forming portion 121 to stamp - form the sheet between the first die 110 and the second die 120. The punching mechanism 200 has a punching punch 210 and a punching die 220. The punching punch 210 extends in the die - closing direction and penetrates through the first die 110, and the length exposed from the first forming portion 111 is equal to t. The punching die 220 is arranged on the second forming portion 121 at a position corresponding to the punching punch 210. The edge height of the punching die 220 is 5t, and the depth that the punching punch 210 enters the punching die 220 after die - closing is greater than 5t. The blanking mechanism 300 has a blanking die 310, and a receiving hole 311 is provided on the blanking die 310. The opening of the receiving hole 311 faces the second die 120. The first die 110 is arranged in the receiving hole 311, and the size of the receiving hole 311 is adapted to the size of the second die 120. The second die 120 presses the sheet into the receiving hole 311 and closes the die with the first die 110, and the depth that the second die 120 extends into the receiving hole 311 is equal to 10t.

[0048] As described above, by arranging the punching mechanism 200 on the molding mechanism 100, the length that the punching punch 210 is exposed from the first forming portion 111 is equal to t, that is, equal to the thickness of the sheet. Thus, before the first die 110 and the second die 120 are closed to perform molding on the sheet, the punching punch 210 can first punch the positions of the hydrogen, air (oxygen), and cooling water inlet and outlet holes at both ends of the bipolar plate. At the same time, by making the length that the punching punch 210 is exposed from the first forming portion 111 equal to the thickness of the sheet, it can be ensured that the punching punch 210 can completely penetrate the sheet, thereby improving the punching effect.

[0049] In addition, by setting the blanking mechanism 300, the size of the receiving hole 311 is adapted to the size of the second mold 120. Thus, when the second mold 120 presses the sheet into the receiving hole 311 and closes the mold with the first mold 110, the edge of the sheet can be cut by the shearing force between the blanking female die 310 and the second mold 120. At the same time, by making the depth of the second mold 120 extending into the receiving hole 311 be 10t, it can be ensured that the waste material cut from the edge of the sheet can be completely separated from the sheet, that is, when the first mold 110 and the second mold 120 close the mold to press the sheet into a bipolar plate, the separation from the edge waste material is achieved simultaneously.

[0050] Thus, the metal bipolar plate composite forming die 10 in the present application can, through one pressing-down action, simultaneously achieve the perforation, blanking, and molding of the sheet. Thereby, the production steps of the bipolar plate can be reduced, the production rhythm can be increased, and the production efficiency of the bipolar plate can be improved.

[0051] In some embodiments, the molding mechanism 100 further includes a first mounting plate 130 and a first spring 140. Among them, the blanking female die 310 is fixedly mounted on the first mounting plate 130, and the first spring 140 is arranged on the opening side of the first mold 110 facing away from the receiving hole 311, pushing the first mold 110 to move towards the second mold 120 so that the first forming portion 111 is flush with the opening of the receiving hole 311. When the depth of the second mold 120 extending into the receiving hole 311 is equal to 10t, the first mold 110 abuts against the first mounting plate 130. Thus, by setting the first spring 140, the first spring 140 is used to push the first mold 110 towards the second mold 120, so that the first mold 110 can become a floating mold. Thereby, when the second mold 120 and the first mold 110 close the mold, the sheet can be clamped into the receiving hole 311, so that the stability of the sheet can be improved, and further the stability during trimming the edge of the sheet can be improved, so as to improve the trimming effect and the molding effect.

[0052] In some embodiments, a first abutting surface 312 is provided on the inner peripheral surface of the receiving hole 311, and the first abutting surface 312 faces the first mounting plate 130. On the outer peripheral surface of the first mold 110, a second abutting surface 112 is provided at a position corresponding to the first abutting surface 312. When the first forming portion 111 is flush with the opening of the receiving hole 311, the first abutting surface 312 abuts against the second abutting surface 112. Thus, through the abutting fit between the first abutting surface 312 and the second abutting surface 112, it is possible to prevent the first mold 110 from exposing from the opening of the receiving hole 311 under the push of the first spring 140, thereby avoiding the first mold 110 from lifting the sheet from the blanking concave die 310, so as to improve the stability of the sheet. At the same time, by avoiding the first mold 110 from lifting the sheet from the blanking concave die 310, the sheet is placed on the blanking concave die 310, so that it is convenient for the following blank holder 160 to clamp the edge of the sheet on the blanking concave die 310, thereby improving the blank holding effect.

[0053] In some embodiments, after the second mold 120 extends into the receiving hole 311, the clearance between the second mold 120 and the receiving hole 311 is 0.1t. Thus, by setting the clearance between the second mold 120 and the receiving hole 311 to 0.1t, the stability of the second mold 120 when pressing the sheet can be improved, and further the forming effect during the forming of the bipolar plate can be improved.

[0054] In some embodiments, the molding mechanism 100 further includes a second mounting plate 150, a blank holder 160 and a second spring 170. Among them, the second mold 120 is fixed on the second mounting plate 150, and the second mounting plate 150 is used for connecting with a press and moves along the die closing direction under the drive of the press. The blank holder 160 is sleeved on the second mold 120 and is slidably connected with the second mold 120 along the die closing direction. The second spring 170 is installed on the second mounting plate 150 and pushes the blank holder 160 to expose from the second mold 120 toward the first mold 110. Thus, by providing the blank holder 160 and the second spring 170, the blank holder 160 exposes from the second mold 120 toward the first mold 110, so that before the second mold 120 moves toward the first mold 110 for die closing, the blank holder 160 can first clamp and fix the edge of the sheet on the blanking concave die 310. Thus, the stability of the sheet can be improved, and further the stability during trimming and die pressing forming of the sheet can be improved to improve the forming effect of the bipolar plate.

[0055] In some embodiments, the second spring 170 is an adjustable pressure spring, and the pressure of the second spring 170 is set to 65 kN. Thus, by setting the second spring 170 as an adjustable pressure spring, the pressure of the blank holder 160 on the edge of the sheet can be adjusted as needed. Thereby, not only can the adaptation range be improved, but also by setting an appropriate blank holding force, defects such as wrinkling or cracking of the sheet during the forming process can be prevented. In addition, by setting the pressure of the second spring 170 to 65 kN, the pressing and fixing effect of the blank holder 160 on the edge of the sheet can be improved.

[0056] In some embodiments, the blanking mechanism 300 further includes a waste ejector rod 330 and a third spring 340. Among them, the waste ejector rod 330 is disposed in the punching die 220, and the third spring 340 is disposed in the second die 120 to drive the end of the waste ejector rod 330 to extend to the edge end of the cutting edge of the punching die 220. Thus, by providing the waste ejector rod 330 and the third spring 340, after the bipolar plate is formed, the third spring 340 can drive the waste ejector rod 330 to eject the waste cut by the punching punch 210 and the punching die 220 on the sheet from the punching die 220, so that automatic blanking can be achieved, which is convenient for the user to clean.

[0057] In some embodiments, the third spring 340 is an adjustable pressure spring. Thus, by setting the third spring 340 as an adjustable pressure spring, the thrust when the punching punch 210 ejects the waste from the punching die 220 can be adjusted, thereby improving the blanking effect.

[0058] In some embodiments, the cavity 20 is bent to form a plurality of hydrogen-oxygen flow channel portions and cooling water flow channel portions arranged alternately. The hydrogen-oxygen flow channel portions are recessed and formed in the direction towards the second die 120, and the cooling water flow channel portions are recessed and formed in the direction towards the first die 110. The hydrogen-oxygen flow channel portions and the cooling water flow channel portions are serpentine channels. Thus, after the first die 110 and the second die 120 are closed to form the cavity 20, the hydrogen-oxygen flow channels and the cooling water flow channels in the shape of serpentine channels can be formed on both side surfaces of the sheet along with the cavity 20.

[0059] In some embodiments, the thickness of the cavity 20 is t, the bottom width of the hydrogen-oxygen flow channel portion is 4t, and the bottom width of the cooling water flow channel portion is 12t. Thus, by making the thickness of the cavity 20 be t, the bottom width of the hydrogen-oxygen flow channel portion be 4t, and the bottom width of the cooling water flow channel portion be 12t, the forming effect of the bipolar plate can be improved.

[0060] The above content has made an exemplary description of the possible embodiments of the metal bipolar plate composite forming die 10. Next, with reference to the drawings, the specific structure of the metal bipolar plate composite forming die 10 will be described in detail in a specific embodiment.

[0061] Figure 1 This is a schematic structural diagram of the metal bipolar plate composite forming die 10 in this application. As Figure 1 shown, the metal bipolar plate composite forming die 10 in the embodiment is used to process a metal plate with a thickness t = 0.1 mm. The metal bipolar plate composite forming die 10 includes a molding mechanism 100, a punching mechanism 200, and a blanking mechanism 300. Among them, the molding mechanism 100 is used to perform molding on the plate, the punching mechanism 200 is used to punch holes for the inlet and outlet of hydrogen, air (oxygen), and cooling water at both ends of the bipolar plate on the plate, and the blanking mechanism 300 is used to separate the bipolar plate formed by processing the plate from the waste material cut and removed.

[0062] Figure 2 is Figure 1 a top view of the corresponding part of the first die 110 in Figure 1 、 Figure 2 shown. As

[0063] shown, the molding mechanism 100 further includes a first mounting plate 130 and a first spring 140. Among them, the first mounting plate 130 is fixedly arranged, and a plurality of first springs 140 are arranged and installed on the upper surface of the first mounting plate 130. The first die 110 is arranged above the first mounting plate 130, and the lower surface of the first die 110 is connected to the first spring 140, so that the first die 110 forms a floating die that can move up and down on the first mounting plate 130. Figure 1 As

[0064] shown, Figure 1 、 Figure 2As shown, the punching mechanism 200 has a punching punch 210 and a punching die 220. Among them, there are 6 punching punches 210, which are located at the corresponding positions of the hydrogen, air (oxygen) and cooling water inlet and outlet holes at both ends of the bipolar plate. The punching punches 210 are vertically arranged. The first die 110 is provided with positioning holes at the corresponding positions of the punching punches 210, and the punching punches 210 are inserted through the positioning holes on the first die 110. The unilateral clearance between the punching punch 210 and the positioning hole is 1 / 10 of the thickness of the plate, that is, the unilateral clearance is 0.01 mm. The lower end of the punching punch 210 is fixed on the first mounting plate 130 through a punch fixing plate and bolts, and the upper end is exposed by the first forming part 111. The exposed length is equal to the thickness t of the plate, that is, 0.1 mm is exposed.

[0065] As Figure 1 shown, the punching die 220 is arranged in the second die 120 at the corresponding position of the punching punch 210. Specifically, the punching die 220 is in the shape of a vertically arranged through hole, and a cutting edge is provided at the lower end, and the cutting edge is located at the corresponding position of the second forming part 121. The height of the cutting edge of the punching die 220 is 5 times the thickness of the plate, that is, the height of the cutting edge is 0.5 mm, so as to ensure that the plate is completely separated. After the die is closed, the depth of the punching punch 210 entering the punching die 220 is greater than the height of the cutting edge. In this embodiment, it is set to 0.6 mm.

[0066] As Figure 1 shown, the blanking mechanism 300 has a blanking die 310. The blanking die 310 is a square block part and is fixedly installed on the first mounting plate 130. A receiving hole 311 in the shape of a vertically arranged through hole is provided on the blanking die 310. The first die 110 is arranged in the receiving hole 311. The size of the receiving hole 311 is adapted to the size of the second die 120, so that the second die 120 can extend downward into the receiving hole 311 under the drive of the press. A plurality of positioning pins 320 are also provided around the upper end opening of the receiving hole 311. The shape enclosed by the positioning pins 320 is adapted to the shape of the plate, so that feeding can be facilitated, and the plate is positioned through the positioning pins 320 to make the plate in a predetermined position.

[0067] The second die 120 presses the plate into the receiving hole 311 to close the die with the first die 110. When the depth of the second die 120 extending into the receiving hole 311 is equal to 10t, the lower surface of the first die 110 abuts against the first mounting plate 130, and the die closing of the first die 110 and the second die 120 is completed. After the second die 120 extends into the receiving hole 311, the unilateral clearance value δ between the second die 120 and the receiving hole 311 is 1 / 10 of the thickness of the plate, that is, δ = 0.01 mm.

[0068] In addition, while pressing the sheet into the accommodation hole 311, the second die 120 cooperates with the blanking concave die 310 to shear the outer part of the top opening of the accommodation hole 311, thereby realizing the trimming operation of the sheet. By making the depth of the second die 120 extending into the accommodation hole 311 equal to 10t, it is also possible to ensure that the waste material at the edge of the sheet is completely separated from the part of the sheet used for pressing into the bipolar plate.

[0069] As Figure 1 shown, the inner peripheral surface of the accommodation hole 311 is stepped and has a first abutting surface 312 arranged downward. The shape of the first die 110 is adapted to the accommodation hole 311, and the outer peripheral surface of the first die 110 is stepped in a matching manner and has a second abutting surface 112 arranged upward. The second abutting surface 112 is located below the first abutting surface 312. The first die 110 moves vertically upward under the push of the first spring 140. When the first forming part 111 is flush with the upper end opening of the accommodation hole 311, the first abutting surface 312 abuts against the second abutting surface 112.

[0070] As Figure 1 shown, the blanking mechanism 300 further has a waste ejector rod 330 and a third spring 340. Among them, the waste ejector rod 330 is arranged in the punching concave die 220 and is adapted to the shape of the punching concave die 220. The third spring 340 is an adjustable pressure spring and is arranged in the cavity in the second die 120. The upper end is fixedly connected to the second mounting plate 150, and the lower end is fixedly connected to the waste ejector rod 330, driving the end of the waste ejector rod 330 to extend to the edge end of the punching concave die 220.

[0071] As Figure 1 shown, the molding mechanism 100 further includes a second mounting plate 150, a blank holder 160 and a second spring 170. Among them, the second mounting plate 150 is used for transmission connection with the press and can move up and down under the drive of the press. The second die 120 is fixed on the second mounting plate 150 and can move up and down along with the second mounting plate 150 to complete the die closing action. The blank holder 160 is located at the corresponding position above the blanking concave die 310, sleeved on the second die 120, and is slidably connected to the second die 120 in the vertical direction. The second spring 170 is installed on the second mounting plate 150 and pushes the blank holder 160 to expose from the second die 120 toward the first die 110 side. Thus, before the press drives the second die 120 to move toward the first die 110 for die closing, the blank holder 160 can first press and fix the edge of the sheet on the blanking concave die 310. The second spring 170 is an adjustable pressure spring, and the pressing force of the blank holder 160 on the edge of the sheet can be adjusted as needed. In this embodiment, the pressure of the second spring 170 is set to 65 kN.

[0072] Figure 3 For Figure 1Partial enlarged view of the cavity 20 formed by the first mold 110 and the second mold 120; Figure 4 is Figure 1 Partial enlarged view of the first forming portion 111 of the first mold 110 in Figure 5 is Figure 1 Partial enlarged view of the second forming portion 121 of the second mold 120 in. As Figures 3 - 5 shown, after the first mold 110 and the second mold 120 are closed, the cavity 20 is formed. The thickness of the cavity 20 (the gap between the first mold 110 and the second mold 120 after closing) is equal to the thickness of the sheet. The cavity 20 is bent to form a plurality of alternately arranged hydrogen-oxygen flow channel portions and cooling water flow channel portions. The hydrogen-oxygen flow channel portions are recessed and formed in the direction towards the second mold 120, and the cooling water flow channel portions are recessed and formed in the direction towards the first mold 110. The hydrogen-oxygen flow channel portions and the cooling water flow channel portions are serpentine channels. Thus, after the first mold 110 and the second mold 120 are closed to form the cavity 20, the sheet is bent along with the cavity 20, and serpentine-channel-shaped hydrogen-oxygen flow channels and cooling water flow channels are formed on both side surfaces of the sheet.

[0073] As Figure 3 shown, the included angle between the two walls of the hydrogen-oxygen flow channel portion is α, and the corresponding angles of the first mold 110 and the second mold 120 are also α, with α = 15°. Figure 3 In, the dimension b of the first mold 110 is the bottom width of the hydrogen-oxygen flow channel portion, and b = 4t. Figure 3 In, the dimension B of the second mold 120 is the ridge width of the hydrogen-oxygen flow channel portion, where B = b + 2 × t × tan((90 - α) / 2). The thickness t of this bipolar plate is 0.1 mm and b = 0.4 mm, then B = 0.553 mm. The dimension H of the first mold 110 is the depth of the hydrogen-oxygen flow channel portion, which is 3 times the thickness of the sheet, and H = 0.3 mm. Figure 3 In, the dimension a of the second mold 120 is the bottom width of the cooling water flow channel portion, and A is the ridge width of the cooling water flow channel portion, and A = a + 2 × t × tan((90 - α) / 2). a = 12t, that is, a = 1.2 mm and A = 1.353 mm. Figure 3 In, the outer fillet r of the second mold 120 = t, and the inner fillet R of the first mold 110 = r + t, that is, r = 0.1 mm and R = 0.2 mm. The distance C between two adjacent hydrogen-oxygen flow channel portions or cooling water flow channel portions = a + B + 2 × H × tan(α / 2), that is, C = 1.914 mm. After all the sheets are pressed into bipolar plates, all the flow channels are serpentine channels, the number of flow channels is 90, and the dimensions of each hydrogen-oxygen flow channel portion or cooling water flow channel portion are the same.

[0074] As Figure 4 shown, Figure 4 The A in Figure 3 and the A in Figure 4 have the same meaning, which is the ridge width of the cooling water flow channel portion, Figure 4 The b inFigure 3 The meaning of b in is the same, which is the bottom width of the hydrogen-oxygen flow channel part. L is the distance between two peaks of the serpentine flow channel, L = 12 mm, R1 = 3.6 mm, R2 = 4 mm, and β = 130°.

[0075] As Figure 5 shown, Figure 5 The B in Figure 3 has the same meaning as the B in , which is the ridge width of the hydrogen-oxygen flow channel part. Figure 4 The a in Figure 3 has the same meaning as the a in , which is the bottom width of the cooling water flow channel part. L is the distance between two peaks of the serpentine flow channel, L = 12 mm, R1 = 3.6 mm, R2 = 4 mm, and β = 130°.

[0076] Figure 6 is the flow chart for processing the bipolar plate using the metal bipolar plate composite forming die 10. As Figure 6 shown, the specific process for processing the bipolar plate using the metal bipolar plate composite forming die 10 includes:

[0077] Step S910, loading.

[0078] In step S910, a metal sheet with a thickness of 0.1 mm is selected, the surface scratches and other defects of the metal sheet are inspected, and after cleaning the surface of the sheet, the sheet is placed between the positioning pins 320 of the blanking concave die 310, and the sheet is positioned by the positioning pins 320.

[0079] Step S920, blank holding.

[0080] The press slider moves downward, driving the second mounting plate 150 to move downward. The blank holder 160 first contacts the sheet, and by adjusting the elastic force of the second spring 170, the pressure applied by the blank holder 160 on the sheet is adjusted, and the pressure is adjusted to an appropriate value, such as 65 kN, to prevent defects such as wrinkling or cracking of the sheet during the forming process.

[0081] Step S930, punching.

[0082] In step S930, before the second die 120 and the first die 110 are closed, the punching punch 210 first cooperates with the punching concave die 220 to complete the punching of the sheet, so that through holes are formed at the hydrogen, air (oxygen), and cooling water inlet and outlet positions in the pipe areas at both ends of the bipolar plate on the sheet. That is, before the sheet is bent to form a flow channel by closing the die, the punching of the hydrogen, air (oxygen), and cooling water inlets and outlets in the pipe areas at both ends of the bipolar plate is completed.

[0083] Step S940, blanking and forming.

[0084] In step S940, blanking and forming start after the punching operation is completed. Its function is to precisely form the distribution area, flow field area, and sealing area of the bipolar plate, and simultaneously complete blanking and forming. The sheet after punching continues to move downward driven by the press slider and fits with the floating first die 110. After the first spring 140 installed under the first die 110 is compressed by a certain stroke, the second die 120 cooperates with the blanking concave die 310 to cut the edge of the sheet, and complete blanking under the push of the second die 120, realizing the separation of the sheet in the bipolar plate area from the waste material at the edge of the sheet. Then the first die 110 continues to move downward and contacts the first mounting plate 130, and the second die 120 is closed with the first die 110 to complete the forming of the bipolar plate flow channel.

[0085] Step S950, material discharging.

[0086] In step S950, after the blanking and forming operations are completed, the press moves upward. The first die 110 also moves upward under the action of the first spring 140, ejecting the processed bipolar plate from the blanking concave die 310 with a stroke of 1 mm. The first die 110 is limited by the cooperation between the first abutting surface 312 and the second abutting surface 112. The press continues to move upward, and the waste ejector rod 330 located in the second die 120 ejects the waste material in the punching concave die 220. Finally, after the press returns to the top dead center, the waste material can be cleaned and the bipolar plate can be taken away to prepare for the production of the next part.

[0087] As described above, every time the press moves downward and then returns, three operations of punching, blanking, and forming can be completed at one station.

[0088] Note that the above is only the preferred embodiment of the present application and the technical principles applied. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described here, and various obvious changes, re-adjustments, and substitutions can be made by those skilled in the art without departing from the protection scope of the present invention. Therefore, although the present application has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments. Without departing from the concept of the present invention, more other equivalent embodiments can be included, all of which fall within the protection scope of the present invention.

Claims

1. A composite forming die for a metal bipolar plate, characterized in that, For pressing a metal sheet into a bipolar plate, the thickness t of the sheet is 0.03 - 0.1 mm; it includes: A molding mechanism, the molding mechanism has a first mold and a second mold. On one surface of the first mold facing the second mold, there is a first forming part. On one surface of the second mold facing the first mold, there is a second forming part. After the first mold and the second mold are closed in the mold - closing direction, a cavity is formed between the first forming part and the second forming part, and the sheet between the first mold and the second mold is stamped into shape. A punching mechanism, the punching mechanism has a punching punch and a punching die. The punching punch extends along the mold - closing direction and penetrates through the first mold, and the length exposed from the first forming part is equal to t; the punching die is arranged on the second forming part at a position corresponding to the punching punch; the edge height of the punching die is 5t, and after closing the mold, the depth that the punching punch enters the punching die is greater than 5t. A blanking mechanism, the blanking mechanism has a blanking die. A receiving hole is arranged on the blanking die, and the opening of the receiving hole faces the second mold. The first mold is arranged in the receiving hole, and the size of the receiving hole is adapted to the size of the second mold. The second mold presses the sheet into the receiving hole and closes the mold with the first mold, and the depth that the second mold extends into the receiving hole is equal to 10t.

2. The metal bipolar plate composite forming die according to claim 1, wherein The molding mechanism further includes: A first mounting plate, and the blanking die is fixedly mounted on the first mounting plate. A first spring, the first spring is arranged on the side of the first mold facing away from the opening of the receiving hole, and pushes the first mold to move towards the second mold, so that the first forming part is flush with the opening of the receiving hole. When the depth that the second mold extends into the receiving hole is equal to 10t, the first mold abuts against the first mounting plate.

3. The metal bipolar plate composite forming die according to claim 2, wherein A first abutting surface is arranged on the inner peripheral surface of the receiving hole and faces the first mounting plate; on the outer peripheral surface of the first mold, a second abutting surface is arranged at a position corresponding to the first abutting surface. When the first forming part is flush with the opening of the receiving hole, the first abutting surface abuts against the second abutting surface.

4. The metal bipolar plate composite forming die according to claim 1, wherein, After the second mold extends into the receiving hole, the gap between the second mold and the receiving hole is 0.1t.

5. The metal bipolar plate composite forming die according to claim 1, wherein, The molding mechanism further includes: A second mounting plate, the second mold is fixed on the second mounting plate, and the second mounting plate is used to connect with a press and moves along the mold - closing direction under the drive of the press. A blank - holding ring, the blank - holding ring is sleeved on the second mold and is slidably connected with the second mold along the mold - closing direction. A second spring, the second spring is installed on the second mounting plate and pushes the blank - holding ring to expose from the second mold towards the first mold side.

6. The metal bipolar plate composite forming die according to claim 5, characterized in that, The second spring is an adjustable - pressure spring, and the pressure of the second spring is set to 65 kN.

7. The metal bipolar plate composite forming die according to claim 1, characterized in that, The blanking mechanism further includes: A waste ejector rod, and the waste ejector rod is arranged in the punching die. The third spring is arranged inside the second die and drives the end of the waste ejector rod to extend to the edge end of the punching female die.

8. The metal bipolar plate composite forming die according to claim 7, characterized in that, The third spring is an adjustable pressure spring.

9. The metal bipolar plate composite forming die according to claim 7, wherein The cavity is bent to form a plurality of hydrogen-oxygen flow channel parts and cooling water flow channel parts which are arranged alternately. The hydrogen-oxygen flow channel parts are recessed and formed in the direction towards the second die, and the cooling water flow channel parts are recessed and formed in the direction towards the first die. The hydrogen-oxygen flow channel parts and the cooling water flow channel parts are serpentine channels.

10. The metal bipolar plate composite forming die according to claim 9, characterized in that, The thickness of the cavity is t, the bottom width of the hydrogen-oxygen flow channel part is 4t, and the bottom width of the cooling water flow channel part is 12t.

Images