Metal bipolar plate forming mold and method

Abstract

This invention relates to a metal bipolar plate forming mold, comprising: an upper mold having an upper groove recessed inward from its surface on one side; and a lower mold spaced apart from the upper mold, having a lower groove recessed inward from its surface on the side near the upper groove. When the upper mold and the lower mold are driven to move towards each other and close, the upper groove and the lower groove form a sealed cavity for stamping, and the upper mold or the lower mold has an air inlet and an air outlet communicating with the sealed cavity. By controlling the upper and lower molds to close and form a cavity, and introducing gas to simultaneously form the upper and lower plates, and by controlling the upper and lower molds to open and using the lower mold to support the upper and lower plates, a bipolar plate can be welded together. Introducing gas into the welded bipolar plate allows for airtightness testing. The upper and lower plates can be formed in one mold body in a single operation, significantly reducing the manufacturing cost of bipolar plates and improving production efficiency.

Description

Technical Field

[0001] This invention relates to the field of bipolar plate manufacturing, and particularly to a metal bipolar plate forming mold and method. Background Technology

[0002] Currently, the function of bipolar plates is to provide gas flow channels, prevent hydrogen and oxygen from mixing in the battery chamber, and establish a current path between the series-connected anode and cathode. As a core component of the fuel cell stack, bipolar plates account for approximately 24% of the total cost. Reducing their manufacturing cost is of great significance for the widespread application of hydrogen fuel cells.

[0003] In related technologies, metal bipolar plates are commonly used, which are precision stamped. The upper and lower plates of the bipolar plate are laser welded together. After the product is completed, the corresponding airtightness test is carried out. These processes are completed in steps, and each step requires special tooling, which is costly and inefficient.

[0004] Therefore, it is necessary to propose a metal bipolar plate forming mold and method to solve the above problems. Summary of the Invention

[0005] This invention provides a metal bipolar plate forming mold and method to solve the problems of high cost and low efficiency in related technologies where the processes are completed in steps and each step requires dedicated tooling.

[0006] In a first aspect, a metal bipolar plate forming mold is provided, comprising: an upper mold having an upper groove recessed inward from its surface on one side; and a lower mold spaced apart from the upper mold, having a lower groove recessed inward from its surface on the side near the upper groove; when the upper mold and the lower mold are driven to move toward each other to close, the upper groove and the lower groove can form a sealed cavity for stamping, and the upper mold or the lower mold is provided with an air inlet and an air outlet communicating with the sealed cavity.

[0007] In some embodiments, the upper mold includes an upper mold base and an upper mold insert, the upper mold base surrounding the outer perimeter of the upper mold insert, and the upper mold base and the upper mold insert are movable relative to each other, the upper mold insert forming the sealing cavity with the lower mold.

[0008] In some embodiments, the upper mold insert includes a first upper mold insert and a second upper mold insert arranged side by side, the second upper mold insert being located on opposite sides of the first upper mold insert, and the second upper mold insert and the first upper mold insert being movable relative to each other.

[0009] In some embodiments, the lower mold includes a lower mold base and a lower mold insert, the lower mold base is disposed around the outer side of the lower mold insert, and the lower mold base and the lower mold insert are movable relative to each other, the lower mold insert and the upper mold forming the sealing cavity.

[0010] In some embodiments, the lower mold insert includes a first lower mold insert and a second lower mold insert arranged side by side, the second lower mold insert being located on opposite sides of the first lower mold insert, and the first lower mold insert and the second lower mold insert being movable relative to each other.

[0011] In some embodiments, the upper mold and the lower mold are provided with sealing grooves on the sides that are close to each other. The sealing grooves are serrated, and the size of the serrations gradually increases from the outside to the inside and then gradually decreases.

[0012] Secondly, a method for forming a metal bipolar plate is provided, comprising the following steps: placing upper and lower bipolar plate sheets into the upper groove of an upper mold and the lower groove of a lower mold, respectively; driving the upper and lower molds to close, thereby forming a sealed cavity; introducing and pressurizing gas through an air inlet on the upper or lower mold, using the gas pressure to force the upper and lower sheets to adhere to the upper and lower grooves and form the plate; driving the upper and lower molds to separate, and welding the upper and lower sheets to form the bipolar plate; driving the upper and lower molds to close, and introducing gas through the air inlet of the bipolar plate for airtightness testing.

[0013] In some embodiments, the upper mold includes an upper mold base and an upper mold insert, and the lower mold includes a lower mold base and a lower mold insert; driving the upper mold and the lower mold to close, so that the upper groove and the lower groove form a sealed cavity, includes: driving the upper mold base and the lower mold base to close, and using the upper mold insert and the lower mold insert to enclose the sealed cavity.

[0014] In some embodiments, the upper mold insert includes a first upper mold insert and a second upper mold insert, and the lower mold insert includes a first lower mold insert and a second lower mold insert; the step of driving the upper mold and the lower mold to separate and welding the upper and lower material pieces to form a bipolar plate includes: driving the upper mold base to separate from the lower mold base, driving the second upper mold insert to separate from the second lower mold insert, driving the first upper mold insert to close and press the upper and lower material pieces together; and welding the upper and lower material pieces to form the bipolar plate.

[0015] In some embodiments, the step of driving the upper mold and the lower mold to close and introducing gas through the air inlet of the bipolar plate for air tightness testing includes: driving the upper mold insert and the lower mold insert to close, driving the upper mold base to separate from the lower mold base; introducing gas through the air inlet of the bipolar plate for air tightness testing; if there is airflow at the outer edge of the closed upper mold insert and the lower mold insert, it indicates that the product has leakage; otherwise, there is no leakage.

[0016] The beneficial effects of the technical solution provided by this invention include:

[0017] This invention provides a metal bipolar plate forming mold and method, which fully combines the structural and welding characteristics of the upper and lower bipolar plate sheets. The upper and lower bipolar plate sheets are formed on the upper and lower blocks of a single mold, respectively. By controlling the closing of the upper and lower molds to form a cavity, a certain pressure of gas is introduced to form the upper and lower sheets simultaneously. By controlling the opening of the upper and lower molds, the lower mold supports the upper and lower sheets, which can then be welded to form the bipolar plate. Gas is introduced into the welded bipolar plate to achieve airtightness testing. The upper and lower sheets can be formed in one step within a single mold body, which greatly reduces the manufacturing cost of bipolar plates and improves the production efficiency of bipolar plates. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 A three-dimensional structural schematic diagram of a metal bipolar plate forming mold provided in an embodiment of the present invention;

[0020] Figure 2 This is a schematic diagram of a metal bipolar plate forming mold used for pressure forming, provided in an embodiment of the present invention.

[0021] Figure 3 This is a schematic diagram of a metal bipolar plate forming mold used for welding, provided in an embodiment of the present invention.

[0022] Figure 4 This is a schematic diagram of a metal bipolar plate forming mold used for sealing performance testing, provided in an embodiment of the present invention.

[0023] Figure 5 This is a schematic diagram of the sealing groove of a metal bipolar plate forming mold provided in an embodiment of the present invention;

[0024] Figure 6This is a schematic diagram of the upper and lower bipolar plates provided in an embodiment of the present invention.

[0025] Numbering on the map:

[0026] 1. Air inlet; 2. Sealing groove; 3. First lower mold insert; 4. Second lower mold insert; 5. Lower mold base; 6. Air outlet; 7. Upper mold base; 8. Second upper mold insert; 9. Upper mold insert; 10. First sealing groove; 11. Second sealing groove; 12. Third sealing groove; 13. Fourth sealing groove; 14. Fifth sealing groove; 15. Sixth sealing groove; 16. Sealing cavity; 17. Bipolar plate; 18. Hydraulic cylinder. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] This invention provides a metal bipolar plate forming mold and method, which can solve the problems of high cost and low efficiency in related technologies where the process is completed in steps and each step requires special tooling.

[0029] See Figure 1 , Figure 2 and Figure 6 As shown, an embodiment of the present invention provides a metal bipolar plate forming mold, which may include: an upper mold having an upper groove recessed inward from its surface on one side; and a lower mold spaced apart from the upper mold, having a lower groove recessed inward from its surface on the side near the upper groove. When the upper mold and the lower mold are driven to move towards each other and close, the upper groove and the lower groove can form a sealed cavity 16 for stamping, and the upper mold or the lower mold is provided with an air inlet 1 and an air outlet 6 communicating with the sealed cavity 16. In this embodiment, by controlling the upper and lower molds to close, A sealed cavity 16 is formed, and gas at a certain pressure is introduced through the air inlet 1 to form the upper and lower material sheets simultaneously. After the upper and lower molds are opened, the upper and lower material sheets are supported by the lower mold and welded together to form a bipolar plate. Finally, gas is introduced through the air inlet of the bipolar plate to achieve the airtightness test of the bipolar plate. By fully combining the structural and welding characteristics of the upper and lower material sheets of the bipolar plate, the upper and lower material sheets of the bipolar plate are formed on the upper and lower blocks of a mold respectively. The upper and lower material sheets can be formed in one step in a mold body, which greatly reduces the manufacturing cost of the bipolar plate and improves the production efficiency of the bipolar plate.

[0030] See Figure 1 and Figure 4 As shown, in some embodiments, the upper mold may include an upper mold base 7 and an upper mold insert. The upper mold base 7 surrounds the outer perimeter of the upper mold insert, and the upper mold base 7 and the upper mold insert are movable relative to each other. The upper mold insert and the lower mold form the sealing cavity 16. In this embodiment, both the upper mold base 7 and the upper mold insert are square. The upper mold base 7 has a through hole in its center, and the upper mold insert is embedded in the through hole of the upper mold base 7. The upper mold base 7 and the upper mold insert are controlled by independent hydraulic cylinders to move up and down and to apply pressure. The upper mold base 7 surrounds the outer perimeter of the upper mold insert. When the two are not coplanar, an upper groove can be formed. By driving the upper mold base 7 to close with the lower mold, the upper mold insert and the lower mold are spaced a certain distance apart, and a sealing cavity 16 can be formed between the upper mold insert and the lower groove of the lower mold. During airtightness testing, since the formed bipolar plate is located between the upper mold insert and the lower mold insert, the upper mold base 7 is driven to separate from the lower mold base 5 by driving the upper mold insert and the lower mold insert to close. Then, gas is introduced through the air inlet of the bipolar plate for airtightness testing. If there is airflow at the outer edge of the closed upper mold insert and the lower mold insert, it indicates that the product has leakage; otherwise, there is no leakage. Due to the split design of the upper mold, since the edge of the bipolar plate is close to the edge of the upper mold insert and the lower mold insert, it is more convenient to introduce gas through the air inlet of the bipolar plate during airtightness testing, eliminating the interference of the upper mold base 7 and the lower mold base 5. On the other hand, the surface of the upper mold insert near the lower mold is consistent with the surface of the formed product. If the product surface changes, the upper mold insert can be directly replaced to realize the production change of the product.

[0031] In another embodiment, the upper mold can also be an integral design, with its up-and-down movement and clamping force controlled by a hydraulic cylinder.

[0032] Preferably, the initial sheets of the upper and lower plates of the bipolar plate are placed in the grooves formed by the upper and lower molds respectively. The sheet in the lower mold is positioned by the positioning pin, while the sheet in the upper mold will fall off due to its own weight. Therefore, magnets are installed around the positioning pins to prevent the sheet from falling off by the attraction of the magnets. The upper and lower molds are closed to form a sealed cavity 16. At this time, gas is introduced through the air inlet 1 and pressurized. The upper and lower sheets are adhered to the upper and lower inserts by the gas pressure to complete the integral molding of the upper and lower sheets. The upper and lower sheets are formed in one step by internal high pressure.

[0033] In another embodiment, liquid can be introduced through the inlet and pressurized. The upper and lower pieces are then bonded to the upper and lower inserts by the liquid pressure, completing the integral molding of the upper and lower pieces. The upper and lower pieces are formed in one step by using internal high pressure.

[0034] See Figure 1 and Figure 3As shown, in some embodiments, the upper die insert may include a first upper die insert 9 and a second upper die insert 8 arranged side by side. The second upper die insert 8 is located on opposite sides of the first upper die insert 9. The second upper die insert 8 and the first upper die insert 9 can move relative to each other. In this embodiment, there are two second upper die inserts 8, which are respectively located on opposite sides of the first upper die insert 9 and between the first upper die insert 9 and the upper die base 7. The first upper die insert 9 and the second upper die insert 8 are both controlled by independent hydraulic cylinders to control their up and down movement and clamping force. After the stamping is completed, the upper die base 7 is driven to separate from the lower die base 5, and the first lower die insert 3 and the first upper die insert 9 are closed. The upper and lower welding areas of the bipolar plate are supported on the second lower die insert 4, and the middle non-welding area is pressed by the first lower die insert 3 and the first upper die insert 9. By designing the upper die insert in a split manner, that is, designing the product's surface area in a split manner, one insert is made for the outer welding part of the product, and one insert is made for the inner surface area, which makes welding more convenient.

[0035] See Figure 1 and Figure 4 As shown, in some embodiments, the lower mold includes a lower mold base 5 and a lower mold insert. The lower mold base 5 surrounds the outer perimeter of the lower mold insert, and the lower mold base 5 and the lower mold insert are movable relative to each other. The lower mold insert and the upper mold form the sealing cavity 16. In this embodiment, the lower mold is a split design. Both the lower mold base 5 and the lower mold insert are square. The lower mold base 5 has a through hole in the center, and the lower mold insert is embedded in the through hole of the lower mold base 5. The lower mold base 5 and the lower mold insert are controlled by independent hydraulic cylinders to move up and down and to clamp. The lower mold base 5 surrounds the outer perimeter of the lower mold insert. When the two are not coplanar, a lower groove can be formed. By driving the lower mold base 5 to close with the upper mold, the lower mold insert is spaced a certain distance from the upper mold, and a sealing cavity 16 can be formed between the lower mold insert and the upper groove of the upper mold. 6. During the airtightness test, since the formed bipolar plate is located between the upper mold insert and the lower mold insert, the upper mold base 7 is driven to separate from the lower mold base 5 by driving the upper mold insert and the lower mold insert to close. Then, gas is introduced through the air inlet of the bipolar plate for airtightness testing. If there is airflow at the outer edge of the closed upper mold insert and the lower mold insert, it indicates that the product has leakage; otherwise, there is no leakage. Due to the split design of the upper mold, since the edge of the bipolar plate is close to the edge of the upper mold insert and the lower mold insert, it is more convenient to introduce gas through the air inlet of the bipolar plate during airtightness testing, eliminating the interference of the upper mold base 7 and the lower mold base 5. On the other hand, the surface of the lower mold insert near the upper mold is consistent with the surface of the formed product. If the product surface changes, the lower mold insert can be directly replaced to realize the production change of the product.

[0036] In another embodiment, the lower mold can also be an integral design, with its up-and-down movement and clamping force controlled by a hydraulic cylinder.

[0037] See Figure 1 and Figure 3 As shown, in some embodiments, the lower mold insert includes a first lower mold insert 3 and a second lower mold insert 4 arranged side by side. The second lower mold insert 4 is located on opposite sides of the first lower mold insert 3. The first lower mold insert 3 and the second lower mold insert 4 are movable relative to each other. In this embodiment, there are two second lower mold inserts 4, which are respectively located on opposite sides of the first lower mold insert 3 and between the first lower mold insert 3 and the lower mold base 5. The first lower mold insert 3 and the second lower mold insert 4 are both controlled by independent hydraulic cylinders. With up-and-down movement and clamping force, after stamping is completed, the upper die holder 7 separates from the lower die holder 5, and the first lower die insert 3 and the second lower die insert 4 close with the first upper die insert 9. The welding area of ​​the upper and lower plates of the bipolar plate is supported on the second lower die insert 4, and the middle non-welding area is pressed by the first lower die insert 3 and the first upper die insert 9. By designing the lower die insert in a split manner, that is, designing the product's surface area in a split manner, one insert is made for the outer welding part of the product, and one insert is made for the inner surface area, which makes welding more convenient.

[0038] In another embodiment, the lower mold insert can be a split design or an integral design, and the upper mold insert can be a split design or an integral design. The various modules of the upper mold and the lower mold can be arbitrarily combined separately or as a whole.

[0039] See Figure 1 and Figure 5 As shown, in some embodiments, the upper mold and the lower mold are provided with sealing grooves 2 on their adjacent sides. The sealing grooves 2 are serrated, and the size of the serrations gradually increases and then gradually decreases from the outside to the inside. In this embodiment, the sealing grooves 2 serve a sealing function. The serrated shape of the sealing grooves 2 changes from the mold cavity outwards in a "small-large-small" pattern. The corresponding mold meshing gap also shows a similar pattern, ensuring that when the mold cavity is pressurized, the liquid / gas that leaks out first must pass through the small meshing gap. Only when the internal pressure reaches a certain level will there be a leak. When the internal pressure is too high, the liquid / gas will leak out into the larger meshing gap in the middle. Because there is a certain amount of air inside, it will hinder the leakage of liquid / gas. When the gap is large, the liquid in the gap will only leak out into the outermost small meshing gap when it reaches a certain volume. The small meshing gap further hinders the leakage of liquid / gas. After the molding is completed, the upper and lower inserts will first quickly separate for a certain stroke, forming a certain negative pressure zone inside. The liquid / gas that leaked into the sealing groove 2 will flow back into the sealing cavity 16 and then be discharged through the liquid / gas outlet before proceeding to the next stroke.

[0040] See Figure 1 , Figure 2 and Figure 6As shown, an embodiment of the present invention provides a method for forming a metal bipolar plate, which may include the following steps: placing the upper and lower bipolar plate sheets into the upper groove of the upper mold and the lower groove of the lower mold, respectively; driving the upper and lower molds to close, so that the upper groove and the lower groove form a sealed cavity 16; introducing gas and pressurizing it through the air inlet 1 on the upper mold or the lower mold, using the gas pressure to make the upper and lower sheets adhere to the upper groove and the lower groove and form a bipolar plate; driving the upper mold and the lower mold to separate, welding the upper and lower sheets to form a bipolar plate; driving the upper mold and the lower mold to close, and introducing gas through the air inlet of the bipolar plate to perform an airtightness test.

[0041] See Figure 1 and Figure 2 As shown, in some embodiments, the upper mold includes an upper mold base 7 and an upper mold insert, and the lower mold includes a lower mold base 5 and a lower mold insert; driving the upper and lower molds to close, so that the upper and lower grooves form a sealed cavity 16, includes: driving the upper mold base 7 and the lower mold base 5 to close, and using the upper mold insert and the lower mold insert to form the sealed cavity 16. In this embodiment, during airtightness testing, since the formed bipolar plate is located between the upper mold insert and the lower mold insert, by driving the upper mold insert and the lower mold insert to close, the upper mold base 7 is driven to separate from the lower mold base 5, and then from... Gas is introduced into the air inlet of the bipolar plate for airtightness testing. If there is airflow at the outer edge of the closed upper and lower mold inserts, it indicates that the product has leakage; otherwise, there is no leakage. Due to the split design of the upper mold, since the edge of the bipolar plate is close to the edge of the upper and lower mold inserts, it is easier to introduce gas from the air inlet of the bipolar plate during airtightness testing, eliminating the interference of the upper mold base 7 and the lower mold base 5. On the other hand, the surface of the upper mold insert near the lower mold is consistent with the surface of the molded product. If the product surface changes, the upper mold insert can be directly replaced to realize the production change of the product.

[0042] In another embodiment, the upper and lower molds can also be an integral design. By driving the upper and lower molds to separate, using other tools to cover the bipolar plate, and then introducing gas from the air inlet of the bipolar plate, the air tightness test of the formed bipolar plate can also be performed.

[0043] See Figure 1 and Figure 3As shown, in some embodiments, the upper mold insert may include a first upper mold insert 9 and a second upper mold insert 8, and the lower mold insert includes a first lower mold insert 3 and a second lower mold insert 4; the step of driving the upper mold and the lower mold to separate and welding the upper and lower material pieces to form a bipolar plate includes: driving the upper mold base 7 to separate from the lower mold base 5, driving the second upper mold insert 8 to separate from the second lower mold insert 4, and driving the first upper mold insert 9 to close and press the upper and lower material pieces together; the step of welding the upper mold insert to form a bipolar plate includes: driving the upper mold base 7 to separate from the lower mold base 5, driving the second upper mold insert 8 to separate from the second lower mold insert 4, and driving the first upper mold insert 9 to close and press the first lower mold insert 3 together; the step of welding the upper mold insert to form a bipolar plate includes: driving the upper mold base 7 to separate from the lower mold base 5, driving the second upper mold insert 8 to separate from the second lower mold insert 4, and driving the first upper mold insert 9 to close and press the upper and lower material pieces together; the step of welding the upper mold insert to form a bipolar plate includes: driving the upper mold base 7 to separate from the lower mold base 5, driving the second upper mold insert 8 to separate from the second lower mold insert 4, and driving the first upper mold insert 9 to close and press the first lower mold insert 3 together to press the upper mold insert 8. The blanks are welded to form the bipolar plate. In this embodiment, after the stamping is completed, the upper die holder 7 is driven to separate from the lower die holder 5, the first lower die insert 3 and the first upper die insert 9 are closed, the welding area of ​​the upper and lower blanks of the bipolar plate is supported on the second lower die insert 4, and the middle non-welding area is pressed by the first lower die insert 3 and the first upper die insert 9. By designing the upper die insert in a split manner, that is, designing the product's surface area in a split manner, one insert is made for the outer welding part of the product and one insert is made for the inner surface area, which makes welding more convenient.

[0044] In another embodiment, the upper mold insert and the lower mold insert can also be an integral design. By driving the upper mold insert and the lower mold insert to separate, the upper mold base 7 and the lower mold base 5 are separated. Other tools are used to press the upper and lower material pieces together, and the upper and lower material pieces are welded together to form the bipolar plate.

[0045] See Figure 1 and Figure 4 As shown, in some embodiments, driving the upper mold and the lower mold to close and introducing gas through the air inlet of the bipolar plate for air tightness testing may include: driving the upper mold insert and the lower mold insert to close, driving the upper mold base 7 to separate from the lower mold base 5; introducing gas through the air inlet of the bipolar plate for air tightness testing. If there is airflow at the outer edge of the closed upper mold insert and the lower mold insert, it indicates that the product has leakage; otherwise, there is no leakage. In this embodiment, by driving the upper mold insert and the lower mold insert to close, driving the upper mold base 7 to separate from the lower mold base 5, and then introducing gas through the air inlet of the bipolar plate for air tightness testing, it is more convenient to introduce gas through the air inlet of the bipolar plate during air tightness testing, eliminating the interference of the upper mold base 7 and the lower mold base 5.

[0046] In another embodiment, the upper mold insert and the lower mold insert can be driven to close, thereby driving the upper mold base 7 and the lower mold base 5 to close. Then, the air inlet pipe can be inserted between the upper mold insert and the lower mold insert to introduce gas from the air inlet of the bipolar plate. This can also be used to test the air tightness of the formed bipolar plate.

[0047] During operation, the upper and lower mold bases and inserts are first fully opened. The initial blanks of the upper and lower bipolar plates are installed onto the upper and lower inserts. The upper and lower mold bases are slowly closed to ensure that the sealing cavity 16 does not form a negative pressure. The upper and lower inserts move a certain distance to form a sealing cavity with the upper and lower mold bases. Then, liquid / gas is introduced through the liquid / gas inlet and pressurized to make the upper and lower plates fit against the surface of the upper and lower inserts, completing the upper and lower plate forming. First, the pressure inside the sealing cavity 16 is released. At this time, the upper and lower inserts are quickly separated by a certain distance to create a certain negative pressure in the upper and lower mold base cavities, allowing the liquid / gas leaking out of the sealing groove 2. The liquid flows back into the cavity of the upper and lower mold bases and is then discharged through the liquid / gas outlet. At this time, the upper and lower mold bases separate, the first lower mold insert 3 and the first upper mold insert 9 are pressed down and closed, and the second lower mold insert 4 moves together with the first lower mold insert 3 to ensure that the upper and lower pieces fit together and the welding area is supported. At this time, welding equipment is used to weld the bipolar plates. After welding is completed, the second upper mold insert 8 is pressed down and closed with the second lower mold insert 4. Gas is introduced into the air inlet of the product to test the air tightness of the product. When there is a sound of airflow at the edge of the insert, it indicates that the air tightness of the product does not meet the standard; otherwise, it meets the air tightness requirements.

[0048] The principle of a metal bipolar plate forming mold provided in this embodiment of the invention is as follows:

[0049] By fully considering the structural and welding characteristics of the upper and lower bipolar plates, a forming mold for metal bipolar plates was designed. The basic structure of this mold is consistent with that of a conventional stamping mold. The upper and lower bipolar plates are formed on the upper and lower blocks of a single mold. After the upper and lower molds are closed, a certain amount of liquid or gas is introduced to form the upper and lower plates simultaneously. By controlling the opening and closing of different parts of the upper and lower molds, welding and airtightness testing of the bipolar plates can be achieved. The upper and lower plates can be formed in one step within a single mold body, and welding and airtightness testing can be achieved through the closure of the mold structure. This greatly reduces the manufacturing cost of bipolar plates and provides a completely new manufacturing solution for metal bipolar plates.

[0050] In the description of this invention, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in this invention can be understood according to the specific circumstances.

[0051] It should be noted that in this invention, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0052] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A metal bipolar plate forming mold, characterized in that, It includes: The upper mold has an upper groove recessed inward from its surface on one side; The lower mold is spaced apart from the upper mold, and a lower groove is provided on the side near the upper groove, which is recessed inward from its surface; When the upper mold and the lower mold are driven to move towards each other to close, the upper groove and the lower groove can form a sealed cavity (16) for stamping, and the upper mold or the lower mold is provided with an air inlet (1) and an air outlet (6) communicating with the sealed cavity (16). The upper mold includes an upper mold base (7) and an upper mold insert. The upper mold insert includes a first upper mold insert (9) and a second upper mold insert (8) arranged side by side. The second upper mold insert (8) is located on opposite sides of the first upper mold insert (9). The second upper mold insert (8) and the first upper mold insert (9) are movable relative to each other. The lower mold includes a lower mold base (5) and a lower mold insert. The lower mold insert includes a first lower mold insert (3) and a second lower mold insert (4) arranged side by side. The second lower mold insert (4) is located on opposite sides of the first lower mold insert (3). The first lower mold insert (3) and the second lower mold insert (4) can move relative to each other. The upper mold and the lower mold are provided with sealing grooves (2) on the side that are close to each other. The sealing grooves (2) are serrated, and the size of the serrations gradually increases from the outside to the inside and then gradually decreases.

2. The metal bipolar plate forming mold as described in claim 1, characterized in that: The upper mold base (7) surrounds the outer side of the upper mold insert, and the upper mold base (7) and the upper mold insert can move relative to each other. The upper mold insert and the lower mold form the sealing cavity (16).

3. The metal bipolar plate forming mold as described in claim 1, characterized in that: The lower mold base (5) surrounds the outer side of the lower mold insert, and the lower mold base (5) and the lower mold insert can move relative to each other. The lower mold insert and the upper mold form the sealing cavity (16).

4. A method for forming a metal bipolar plate, using a metal bipolar plate forming mold as described in any one of claims 1-3, characterized in that, It includes the following steps: The upper and lower plates of the bipolar plate are placed in the upper groove of the upper mold and the lower groove of the lower mold, respectively, and the upper mold and the lower mold are driven to close, so that the upper groove and the lower groove form a sealed cavity (16). Gas is introduced and pressurized through the air inlet (1) on the upper mold or the lower mold, and the gas pressure is used to make the upper and lower material pieces adhere to the upper tank and the lower tank and form them; The upper mold and the lower mold are driven to separate, and the upper and lower material sheets are welded together to form a bipolar plate; The upper and lower molds are driven to close, and gas is introduced through the air inlet of the bipolar plate for air tightness testing.

5. The method for forming a metal bipolar plate as described in claim 4, characterized in that: The upper mold includes an upper mold base (7) and an upper mold insert, and the lower mold includes a lower mold base (5) and a lower mold insert; The method of driving the upper and lower molds to close, so that the upper and lower grooves form a sealed cavity (16), includes: Drive the upper mold base (7) and the lower mold base (5) to close, and use the upper mold insert and the lower mold insert to form the sealing cavity (16).

6. The method for forming a metal bipolar plate as described in claim 5, characterized in that: The upper mold insert includes a first upper mold insert (9) and a second upper mold insert (8), and the lower mold insert includes a first lower mold insert (3) and a second lower mold insert (4). The step of driving the upper mold and the lower mold to separate, and welding the upper and lower material sheets to form a bipolar plate includes: Drive the upper mold base (7) to separate from the lower mold base (5), drive the second upper mold insert (8) to separate from the second lower mold insert (4), and drive the first upper mold insert (9) to close with the first lower mold insert (3) and press the upper and lower pieces together; The upper and lower plates are welded together to form the bipolar plate.

7. The method for forming a metal bipolar plate as described in claim 6, characterized in that: The process of driving the upper and lower molds to close and introducing gas through the air inlet of the bipolar plate for airtightness testing includes: Drive the upper mold insert and the lower mold insert to close, and drive the upper mold base (7) to separate from the lower mold base (5); Gas is introduced through the air inlet of the bipolar plate for air tightness testing. If there is airflow at the outer edge of the closed upper mold insert and the lower mold insert, it indicates that the product has leakage; otherwise, there is no leakage.

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