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

A metal bipolar plate composite forming mold Technical Field

[0001] This utility model relates to the field of metal processing technology, and in particular to a composite forming mold for metal bipolar plates. Background Technology

[0002] Hydrogen fuel cells are power generation devices that convert chemical energy into electrical energy through the electrochemical reaction of hydrogen and oxygen. They offer numerous advantages, including zero carbon emissions, high efficiency, low noise, and resistance to low temperatures. Bipolar plates are one of the core components of hydrogen fuel cells, responsible for functions such as current conduction, gas distribution, heat management, and mechanical support. Their performance directly affects the power density, durability, and cost of the fuel cell stack. Metal bipolar plates, due to their high conductivity, lightweight, and ease of processing, have become the mainstream choice for on-board fuel cells. Common materials for metal bipolar plates include aluminum, titanium, and stainless steel, with thicknesses typically ranging from 0.075 to 0.1 mm.

[0003] The bipolar plate consists of four functional zones: a piping zone, a distribution zone, a flow field zone, and a sealing zone. The piping zone primarily forms the supply channels for hydrogen, air, and coolant. The distribution zone is a transition area where reactant gases enter the flow field zone from the common piping zone, ensuring uniform flow of coolant into each channel of the cooling flow field to achieve uniform heat dissipation. The flow field zone corresponds to the active zone of the fuel cell and is a crucial area participating in the reaction, determining the flow state of hydrogen, oxygen, and water within the flow field. The sealing zone primarily uses sealing components to achieve a seal between the bipolar plate and the proton exchange membrane assembly after the fuel cell stack is assembled, in conjunction with the battery module.

[0004] The application of metal bipolar plates requires the use of stamping processes to create large-area flow fields and high-precision flow channels. The surfaces must possess high corrosion resistance and low interfacial contact resistance. Designing and manufacturing high-precision stamping dies is crucial for the efficient production of metal bipolar plates. Therefore, there is an urgent need for a composite forming die for metal bipolar plates to improve production efficiency. Summary of the Invention

[0005] In view of the above-mentioned problems of the prior art, this application provides a metal bipolar plate composite forming mold, which can improve the production efficiency of bipolar plates.

[0006] This application provides a metal bipolar plate composite forming mold for pressing a metal sheet into a bipolar plate, wherein the thickness t of the sheet is 0.03-0.1 mm; comprising:

[0007] A molding mechanism has a first mold and a second mold. The first mold has a first forming part on its surface facing the second mold, and the second mold has a second forming part on its surface facing the first mold. After the first mold and the second mold are closed along the mold closing direction, a cavity is formed between the first forming part and the second forming part, and the sheet metal between the first mold and the second mold is stamped into shape.

[0008] A punching mechanism includes a punch and a die. The punch extends along the mold closing direction and passes through the first mold, with a length of t protruding from the first forming part. The die is disposed on the second forming part at a position corresponding to the punch. The cutting edge height of the die is 5t, and the depth to which the punch enters the die after mold closing is greater than 5t.

[0009] The blanking mechanism has a blanking die with a receiving hole. The opening of the receiving hole faces the second mold. The first mold is disposed in the receiving hole. 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 with the first mold. The depth of the second mold extending into the receiving hole is equal to 10t.

[0010] With the above structure, a punching mechanism can be set on the molding mechanism so that the length of the punch protruding from the first forming part is equal to t, which is equal to the thickness of the sheet metal. This allows the punch to pre-cut the hydrogen, air (oxygen), and cooling water inlet / outlet holes at both ends of the bipolar plate before the first and second molds close to mold the sheet metal. Simultaneously, by ensuring that the length of the punch protruding from the first forming part is equal to the thickness of the sheet metal, it can be guaranteed that the punch can completely penetrate the sheet metal, thereby improving the punching effect.

[0011] In addition, by setting up a blanking mechanism to match the size of the receiving hole with the size of the second mold, the edge of the sheet can be trimmed by the shearing force between the blanking die and the second mold when the second mold presses the sheet into the receiving hole and closes with the first mold. At the same time, by making the second mold extend into the receiving hole to a depth of 10t, it can be ensured that the waste material cut off from the edge of the sheet can be completely separated from the sheet. That is, when the first mold and the second mold close together to press the sheet into a double-layer board, separation from the edge waste is achieved at the same time.

[0012] Therefore, the metal bipolar plate composite forming mold in this application can simultaneously pierce, blank, and mold the plate in a single pressing action. This reduces the number of production steps for bipolar plates, increases production speed, and improves production efficiency.

[0013] In some embodiments, the molding mechanism further includes: a first mounting plate, wherein the blanking die is fixedly mounted on the first mounting plate; a first spring, wherein the first spring is disposed on the side of the first mold facing away from the opening of the receiving hole, and pushes the first mold to move toward the second mold, so that the first molding part is flush with the opening of the receiving hole, and when the second mold extends into the receiving hole to a depth of 10t, the first mold abuts against the first mounting plate.

[0014] By employing the above structure and incorporating a first spring, the first mold is pushed towards the second mold, thus enabling the first mold to become a floating mold. Consequently, when the second mold and the first mold are closed, the sheet metal can be clamped into the receiving hole, thereby improving the stability of the sheet metal and, consequently, the stability during edge trimming, thus enhancing both the trimming and molding effects.

[0015] In some embodiments, a first abutting surface is provided on the inner peripheral surface of the receiving hole, and the first abutting surface is disposed facing the first mounting plate; a second abutting surface is provided on the outer peripheral surface of the first mold at a position corresponding to the first abutting surface, and when the first forming part is flush with the opening of the receiving hole, the first abutting surface abuts against the second abutting surface.

[0016] With the above structure, the first mold can be prevented from being exposed from the opening of the receiving hole under the push of the first spring through the abutting fit between the first abutting surface and the second abutting surface, thereby preventing the first mold from lifting the plate from the blanking die and improving the stability of the plate.

[0017] At the same time, by preventing the first mold from lifting the sheet material from the blanking die, the sheet material is placed on the blanking die, which facilitates the clamping ring to clamp the edge of the sheet material on the blanking die, thereby improving the clamping effect.

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

[0019] By adopting the above structure and setting the gap between the second mold and the receiving hole to 0.1t, the stability of the second mold when pressing the plate can be improved, thereby improving the forming effect when forming the bipolar plate.

[0020] In some embodiments, the molding mechanism further includes: a second mounting plate, the second mold being fixed on the second mounting plate, the second mounting plate being connected to a press and moving along the mold closing direction under the drive of the press; a pressure ring, the pressure ring being sleeved on the second mold and slidably connected to the second mold along the mold closing direction; and a second spring, the second spring being mounted on the second mounting plate and pushing the pressure ring to protrude from the second mold toward the first mold side.

[0021] By employing the above structure and incorporating a pressure ring and a second spring, the pressure ring protrudes from the second mold towards the first mold. This allows the pressure ring to pre-press and fix the edge of the sheet metal onto the blanking die before the second mold moves towards the first mold for mold closing. This improves the stability of the sheet metal, thereby enhancing the stability during trimming and die forming, ultimately improving 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 65kN.

[0023] By employing the above structure and setting the second spring as an adjustable pressure spring, the pressure of the pressure ring on the edge of the sheet metal can be adjusted as needed. This not only improves the adaptability but also prevents defects such as wrinkling or cracking of the sheet metal during the forming process by setting an appropriate pressure force. Furthermore, by setting the second spring pressure to 65kN, the clamping and fixing effect of the pressure ring on the edge of the sheet metal can be improved.

[0024] In some embodiments, the blanking mechanism further includes: a scrap ejector rod disposed within the punching die; and a third spring disposed within the second mold to drive the end of the scrap ejector rod to extend to the cutting edge end of the punching die.

[0025] With the above structure, by setting a scrap ejector rod and a third spring, after the bipolar plate is formed, the scrap ejector rod driven by the third spring will push the scrap punched by the punching punch and the punching die onto the plate through the punching die, thereby achieving automatic unloading and making it convenient for users to clean up.

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

[0027] By adopting the above structure and setting the third spring as an adjustable pressure spring, the thrust of the punch when it pushes the waste out of the punching die can be adjusted, thereby improving the blanking effect.

[0028] In some embodiments, the cavity is bent to form a plurality of alternating hydrogen-oxygen flow channels and cooling water flow channels, which are recessed in the direction of the second mold along the hydrogen-oxygen flow channels and in the direction of the first mold. The hydrogen-oxygen flow channels and the cooling water flow channels are serpentine flow channels.

[0029] With the above structure, after the first mold and the second mold are closed to form a cavity, the sheet metal can form serpentine flow channels and cooling water channels on both sides of the cavity.

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

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

[0032] These and other aspects of this invention will become more readily apparent in the following description of several embodiments. Attached Figure Description

[0033] The various features of this utility model and the relationships between them are further explained below with reference to the accompanying drawings. The drawings are exemplary; some features are not shown to scale, and some drawings may omit conventional features in the field of this application that are not essential to this application, or additional features that are not essential to this application may be shown. The combination of features shown in the drawings is not intended to limit this application. Furthermore, throughout this specification, the same reference numerals refer to the same things. Specific descriptions of the drawings are as follows:

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

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

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

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

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

[0039] Figure 6 is a flowchart of the process of processing bipolar plates using a metal bipolar plate composite forming mold.

[0040] Explanation of reference numerals in the attached figures

[0041] 10 Metal bipolar plate composite forming mold; 100 Molding mechanism; 110 First mold; 111 First forming part; 112 Second abutting surface; 120 Second mold; 121 Second forming part; 130 First mounting plate; 140 First spring; 150 Second mounting plate; 160 Pressure ring; 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 Positioning pin; 330 Scrap ejector; 340 Third spring; 20 Cavity. Detailed Implementation

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

[0043] In the following description, the labels of the steps, such as S110, S120, etc., do not necessarily mean that the steps will be executed in this way. The order of the steps can be interchanged or executed simultaneously if permitted.

[0044] The term "comprising" as used in the specification and claims should not be construed as limiting itself to what follows; it does not exclude other elements or steps. Therefore, it should be interpreted as specifying the presence of the mentioned feature, integral, step, or component, but does not exclude the presence or addition of one or more other features, integrals, steps, or components, or groups thereof. Thus, the statement "device comprising means A and B" should not be limited to a device consisting solely of components A and B.

[0045] The terms "an embodiment" or "an embodiment" as used in this specification mean that a particular feature, structure, or characteristic described in conjunction with that embodiment is included in at least one embodiment of the present invention. Therefore, the terms "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. Furthermore, in one or more embodiments, the particular features, structures, or characteristics can be combined in any suitable manner, as will be apparent to those skilled in the art from this disclosure.

[0046] The specific structure of the metal bipolar plate composite forming mold 10 in this application will be described below with reference to the accompanying drawings.

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

[0048] Therefore, by setting a punching mechanism 200 on the molding mechanism 100, the length of the punching punch 210 exposed from the first forming part 111 is equal to t, which is equal to the thickness of the sheet metal. This allows the punching punch 210 to punch the hydrogen, air (oxygen), and cooling water inlet / outlet holes at both ends of the bipolar plate before the first mold 110 and the second mold 120 complete the molding and forming process. Simultaneously, by ensuring that the length of the punching punch 210 exposed from the first forming part 111 is equal to the thickness of the sheet metal, it is guaranteed that the punching punch 210 can completely penetrate the sheet metal, 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 with the first mold 110, the edge of the sheet can be cut by the shearing force between the blanking die 310 and the second mold 120. At the same time, by making the second mold 120 extend into the receiving hole 311 to a depth of 10t, it can be ensured that the waste material cut off 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 to press the sheet into a double-layer board, the separation from the edge waste is achieved at the same time.

[0050] Therefore, the metal bipolar plate composite forming mold 10 in this application can simultaneously pierce, blank, and mold the plate in a single pressing action. This reduces the number of production steps for bipolar plates, increases production speed, and improves production efficiency.

[0051] In some embodiments, the molding mechanism 100 further includes a first mounting plate 130 and a first spring 140. The blanking die 310 is fixedly mounted on the first mounting plate 130, and the first spring 140 is disposed on the side of the first die 110 facing away from the opening of the receiving hole 311, pushing the first die 110 towards the second die 120, so that the first forming part 111 is flush with the opening of the receiving hole 311. When the second die 120 extends into the receiving hole 311 to a depth of 10t, the first die 110 abuts against the first mounting plate 130. Thus, by providing the first spring 140, which pushes the first die 110 towards the second die 120, the first die 110 can become a floating die. Therefore, when the second die 120 and the first die 110 are closed, the sheet material can be clamped into the receiving hole 311, thereby improving the stability of the sheet material and, consequently, the stability during edge trimming, thus improving both the trimming and molding effects.

[0052] In some embodiments, a first abutting surface 312 is provided on the inner circumferential surface of the receiving hole 311, and the first abutting surface 312 is disposed facing the first mounting plate 130. On the outer circumferential 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 part 111 is flush with the opening of the receiving hole 311, the first abutting surface 312 abuts against the second abutting surface 112. Thus, the abutting engagement between the first abutting surface 312 and the second abutting surface 112 prevents the first mold 110 from being exposed from the opening of the receiving hole 311 under the push of the first spring 140, thereby preventing the first mold 110 from lifting the sheet metal from the blanking die 310, thus improving the stability of the sheet metal. At the same time, by preventing the first mold 110 from lifting the sheet metal from the blanking die 310, the sheet metal is placed on the blanking die 310, thereby facilitating the clamping ring 160 to clamp the edge of the sheet metal onto the blanking die 310, thereby improving the clamping effect.

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

[0054] In some embodiments, the molding mechanism 100 further includes a second mounting plate 150, a pressure ring 160, and a second spring 170. The second mold 120 is fixed to the second mounting plate 150, which is connected to a press and moves along the mold-closing direction under the drive of the press. The pressure ring 160 is sleeved on the second mold 120 and slidably connected to it along the mold-closing direction. The second spring 170 is mounted on the second mounting plate 150 and pushes the pressure ring 160 to protrude from the second mold 120 toward the first mold 110. Thus, by setting the pressure ring 160 and the second spring 170 so that the pressure ring 160 protrudes from the second mold 120 toward the first mold 110, the pressure ring 160 can first press and fix the edge of the sheet metal onto the blanking die 310 before the second mold 120 moves toward the first mold 110 for mold closing. This improves the stability of the sheet material, which in turn improves the stability during trimming and molding, thereby enhancing 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. Therefore, by making the second spring 170 an adjustable pressure spring, the pressure of the pressure ring 160 on the edge of the sheet metal can be adjusted as needed. This not only improves the adaptability but also prevents defects such as wrinkling or cracking of the sheet metal during the forming process by setting an appropriate pressure force. Furthermore, by setting the pressure of the second spring 170 to 65 kN, the clamping and fixing effect of the pressure ring 160 on the edge of the sheet metal can be improved.

[0056] In some embodiments, the blanking mechanism 300 further includes a scrap ejector rod 330 and a third spring 340. The scrap ejector rod 330 is disposed within the punching die 220, and the third spring 340 is disposed within the second mold 120, driving the end of the scrap ejector rod 330 to extend to the cutting edge of the punching die 220. Thus, by providing the scrap ejector rod 330 and the third spring 340, after the bipolar plate is formed, the third spring 340 drives the scrap ejector rod 330 to eject the scrap punched from the plate by the punching punch 210 and the punching die 220 through the punching die 220, thereby achieving automatic blanking and facilitating user cleaning.

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

[0058] In some embodiments, the cavity 20 is bent to form a plurality of alternating hydrogen-oxygen flow channels and cooling water flow channels. The hydrogen-oxygen flow channels are recessed towards the second mold 120, and the cooling water flow channels are recessed towards the first mold 110. The hydrogen-oxygen flow channels and cooling water flow channels are serpentine. Thus, after the first mold 110 and the second mold 120 are closed to form the cavity 20, the sheet metal can form serpentine hydrogen-oxygen flow channels and cooling water flow channels on both sides of the cavity 20.

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

[0060] The above description provides an exemplary description of possible embodiments of the metal bipolar plate composite forming mold 10. Below, with reference to the accompanying drawings, a detailed description of the specific structure of the metal bipolar plate composite forming mold 10 in a particular embodiment will be provided.

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

[0062] Figure 2 is a top view of the corresponding part of the first mold 110 in Figure 1. As shown in Figures 1 and 2, the molding mechanism 100 has a first mold 110 and a second mold 120. The first mold 110 and the second mold 120 are square block parts, with the first mold 110 located directly below the second mold 120. The upper surface of the first mold 110 is the first forming part 111, and the lower surface of the second mold 120 is the second forming part 121. After the first mold 110 and the second mold 120 are closed in the vertical direction (mold closing direction), a cavity 20 is formed between the first forming part 111 and the second forming part 121, and the sheet metal between the first mold 110 and the second mold 120 is stamped and formed.

[0063] As shown in Figure 1, the molding mechanism 100 also includes a first mounting plate 130 and a first spring 140. The first mounting plate 130 is fixedly mounted, and multiple first springs 140 are mounted on the upper surface of the first mounting plate 130. A first mold 110 is positioned above the first mounting plate 130, and the lower surface of the first mold 110 is connected to the first springs 140, forming a floating mold that can move up and down on the first mounting plate 130.

[0064] As shown in Figures 1 and 2, the punching mechanism 200 has punching punches 210 and punching dies 220. Six punches 210 are provided, located at corresponding positions of the hydrogen, air (oxygen), and cooling water inlet / outlet holes at both ends of the bipolar plate. The punches 210 are vertically arranged, and the first die 110 has positioning holes at corresponding positions on the punches 210, through which the punches 210 pass. The gap between the punches 210 and the positioning holes on one side is 1 / 10 of the plate thickness, i.e., a gap of 0.01 mm. The lower end of the punches 210 is fixed to the first mounting plate 130 by a punch fixing plate and bolts, while the upper end protrudes from the first forming part 111, with an exposed length equal to the plate thickness t, i.e., 0.1 mm.

[0065] As shown in Figure 1, the punching die 220 is disposed within the second mold 120, at the position corresponding to the punching punch 210. Specifically, the punching die 220 is a vertically arranged through hole with a cutting edge at its lower end, located at the position corresponding to the second forming part 121. The cutting edge height of the punching die 220 is 5 times the thickness of the sheet metal, i.e., the cutting edge height is 0.5 mm, to ensure complete separation of the sheet metal. After mold closing, the depth to which the punching punch 210 enters the punching die 220 is greater than the cutting edge height, which is set to 0.6 mm in this embodiment.

[0066] As shown in Figure 1, the blanking mechanism 300 has a blanking die 310, which is a square block component and is fixedly mounted on the first mounting plate 130. The blanking die 310 has a vertical through-hole accommodating hole 311. The first mold 110 is disposed within the accommodating hole 311, and the size of the accommodating hole 311 is adapted to the size of the second mold 120, allowing the second mold 120 to extend downward into the accommodating hole 311 under the drive of the press. Multiple positioning pins 320 are also provided around the upper opening of the accommodating hole 311. The shape of the positioning pins 320 is adapted to the shape of the sheet metal, thus facilitating feeding and positioning the sheet metal in a predetermined position.

[0067] The second mold 120 presses the sheet metal into the receiving hole 311 and closes with the first mold 110. When the second mold 120 extends into the receiving hole 311 to a depth of 10t, the lower surface of the first mold 110 abuts against the first mounting plate 130, and the mold closing of the first mold 110 and the second mold 120 is completed. After the second mold 120 extends into the receiving hole 311, the single-sided gap value δ between the second mold 120 and the receiving hole 311 is 1 / 10 of the sheet metal thickness, that is, δ = 0.01mm.

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

[0069] As shown in Figure 1, the inner circumferential surface of the receiving hole 311 is stepped and has a first abutment surface 312 facing downward. The shape of the first mold 110 is adapted to the receiving hole 311, and the outer circumferential surface of the first mold 110 is also stepped and has a second abutment surface 112 facing upward. The second abutment surface 112 is located below the first abutment surface 312. The first mold 110 moves vertically upward under the push of the first spring 140. When the first forming part 111 is flush with the upper opening of the receiving hole 311, the first abutment surface 312 abuts against the second abutment surface 112.

[0070] As shown in Figure 1, the blanking mechanism 300 also includes a scrap ejector rod 330 and a third spring 340. The scrap ejector rod 330 is disposed within the punching die 220 and is adapted to the shape of the punching die 220. The third spring 340 is an adjustable pressure spring, disposed in a cavity within the second mold 120. Its upper end is fixedly connected to the second mounting plate 150, and its lower end is fixedly connected to the scrap ejector rod 330, driving the end of the scrap ejector rod 330 to extend to the cutting edge of the punching die 220.

[0071] As shown in Figure 1, the molding mechanism 100 also includes a second mounting plate 150, a pressure ring 160, and a second spring 170. 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 mold 120 is fixed on the second mounting plate 150 and can move up and down with the second mounting plate 150 to complete the mold closing action. The pressure ring 160 is located at a corresponding position above the blanking die 310, sleeved on the second mold 120, and slidably connected to the second mold 120 in the vertical direction. The second spring 170 is mounted on the second mounting plate 150 and pushes the pressure ring 160 to protrude from the second mold 120 toward the first mold 110. Thus, before the press drives the second mold 120 to move toward the first mold 110 for mold closing, the pressure ring 160 first presses and fixes the edge of the sheet metal onto the blanking die 310. The second spring 170 is an adjustable pressure spring, which can adjust the pressing force of the pressure ring 160 on the edge of the sheet metal as needed. In this embodiment, the pressure of the second spring 170 is set to 65kN.

[0072] Figure 3 is a partially enlarged view of the cavity 20 formed by the first mold 110 and the second mold 120 in Figure 1; Figure 4 is a partially enlarged view of the first forming part 111 of the first mold 110 in Figure 1; Figure 5 is a partially enlarged view of the second forming part 121 of the second mold 120 in Figure 1. As shown in Figures 3-5, the cavity 20 is formed after the first mold 110 and the second mold 120 are closed. The thickness of the cavity 20 (the gap between the first mold 110 and the second mold 120 after mold closing) is equal to the thickness of the sheet metal. The cavity 20 is bent to form multiple alternating hydrogen-oxygen flow channels and cooling water flow channels. The hydrogen-oxygen flow channels are recessed towards the second mold 120, and the cooling water flow channels are recessed towards the first mold 110. The hydrogen-oxygen flow channels and the cooling water flow channels are serpentine flow channels. Therefore, after the first mold 110 and the second mold 120 are closed to form the cavity 20, the sheet metal is bent along with the cavity 20, forming serpentine flow channels for hydrogen and oxygen and cooling water on both sides of the sheet metal.

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

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

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

[0076] Figure 6 is a flowchart of the process of processing bipolar plates using the metal bipolar plate composite forming mold 10. As shown in Figure 6, the specific process of processing bipolar plates using the metal bipolar plate composite forming mold 10 includes:

[0077] Step S910: Loading materials.

[0078] In step S910, a metal sheet with a thickness of 0.1mm is selected, and defects such as scratches on the surface of the metal sheet are checked. After cleaning the surface of the sheet, the sheet is placed between the positioning pins 320 of the blanking die 310, and the sheet is positioned by the positioning pins 320.

[0079] Step S920: Press the edge.

[0080] As the press slide moves downward, it causes the second mounting plate 150 to move downward. The pressure ring 160 first contacts the sheet material. By adjusting the elastic force of the second spring 170, the pressure applied to the sheet material by the pressure ring 160 is adjusted to a suitable value, such as 65kN, to prevent defects such as wrinkling or cracking of the sheet material during the forming process.

[0081] Step S930: Punching.

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

[0083] Step S940: Blanking and forming.

[0084] In step S940, blanking and forming begin after the punching action. Their function is to precisely form the bipolar plate distribution area, flow field area, and sealing area, while simultaneously completing blanking and forming. The punched plate continues to descend under the drive of the press slide, engaging with the floating first mold 110. After the first spring 140 installed under the first mold 110 is compressed by a certain stroke, the second mold 120 cooperates with the blanking die 310 to cut the edge of the plate. The blanking is completed under the push of the second mold 120, achieving separation of the plate in the bipolar plate area from the waste material at the plate edge. Then, the first mold 110 continues to descend and contacts the first mounting plate 130. The second mold 120 closes with the first mold 110, completing the forming of the bipolar plate flow channel.

[0085] Step S950: Unloading.

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

[0087] As shown above, each downward and return stroke of the press can complete the three actions of punching, blanking, and forming in one station.

[0088] Note that the above are merely preferred embodiments and the technical principles employed in this application. Those skilled in the art will understand that this utility model is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the protection scope of this utility model. Therefore, although this application has been described in detail through the above embodiments, this utility model is not limited to the above embodiments. Many other equivalent embodiments may be included without departing from the concept of this utility model, all of which fall within the protection scope of this utility model.

Claims

1. A metal bipolar plate composite forming mold, characterized in that, This device is used to press metal sheets into bipolar plates, wherein the thickness t of the sheet is 0.03-0.1 mm; it includes: a molding mechanism having a first mold and a second mold, wherein a first forming part is provided on the surface of the first mold facing the second mold, and a second forming part is provided on the surface of the second mold facing the first mold; after the first mold and the second mold are closed along the mold closing direction, a cavity is formed between the first forming part and the second forming part, thereby pressing the sheet between the first mold and the second mold into shape; and a punching mechanism having a punching punch and a punching die, wherein the punching punch extends along the mold closing direction and passes through the first mold. On the mold, the length exposed from the first forming part is equal to t; the punching die is set on the second forming part, at the position corresponding to the punching punch; the cutting edge height of the punching die is 5t, and after mold closing, the depth to which the punching punch enters the punching die is greater than 5t; the blanking mechanism has a blanking die, the blanking die is provided with a receiving hole, the opening of the receiving hole faces the second mold, the first mold is set in the receiving hole, 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 to which the second mold extends into the receiving hole is equal to 10t.

2. The metal bipolar plate composite forming mold according to claim 1, characterized in that, The molding mechanism further includes: a first mounting plate, on which the blanking die is fixedly mounted; and a first spring, which is disposed on the side of the first mold facing away from the opening of the receiving hole, pushing the first mold toward the second mold so that the first forming part is flush with the opening of the receiving hole. When the second mold extends into the receiving hole to a depth of 10t, the first mold abuts against the first mounting plate.

3. The metal bipolar plate composite forming mold according to claim 2, characterized in that, A first abutting surface is provided on the inner circumferential surface of the receiving hole, and the first abutting surface is disposed facing the first mounting plate; a second abutting surface is provided on the outer circumferential surface of the first mold at a position corresponding to the first abutting surface, and 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 mold according to claim 1, characterized in that, After the second mold extends into the receiving hole, the gap between it and the receiving hole is 0.1t.

5. The metal bipolar plate composite forming mold according to claim 1, characterized in that, The molding mechanism further includes: a second mounting plate, on which the second mold is fixed, 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 pressure ring, which is sleeved on the second mold and slidably connected to the second mold along the mold closing direction; and a second spring, which is mounted on the second mounting plate and pushes the pressure ring to protrude from the second mold toward the first mold.

6. The metal bipolar plate composite forming mold 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 65kN.

7. The metal bipolar plate composite forming mold according to claim 1, characterized in that, The blanking mechanism further includes: a scrap ejector rod disposed inside the punching die; and a third spring disposed inside the second mold to drive the end of the scrap ejector rod to extend to the cutting edge end of the punching die.

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

9. The metal bipolar plate composite forming mold according to claim 7, characterized in that, The cavity is bent to form multiple alternating hydrogen-oxygen flow channels and cooling water flow channels. The hydrogen-oxygen flow channels are recessed towards the second mold, and the cooling water flow channels are recessed towards the first mold. The hydrogen-oxygen flow channels and cooling water flow channels are serpentine flow channels.

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

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