Stamping die and stamping process for explosion-proof valve mounting hole in side wall of battery shell

Abstract

The invention provides a stamping die and a stamping process for an anti-explosion valve mounting hole in the side wall of a battery shell, the stamping die comprises an upper die assembly, the upper die assembly comprises an upper die base, and the upper die base is provided with a punching punch, a first upsetting punch and a second upsetting punch; the lower die assembly comprises a lower die base, a first working procedure die core, a second working procedure die core and a third working procedure die core are evenly arranged on the lower die base at intervals, the first working procedure die core corresponds to the punching punch, the second working procedure die core corresponds to the first upsetting punch, and the third working procedure die core corresponds to the second upsetting punch. The third working procedure die core corresponds to the second upsetting punch, and a blanking hole is formed in the first working procedure die core; the guide column assembly is arranged between the upper die base and the lower die base, and the upper die base can slide up and down along the guide column assembly. The problem that in the prior art, it is difficult to arrange an anti-explosion valve mounting hole in the side wall of a blade-shaped battery shell is solved.

Description

Technical Field

[0001] This invention relates to the field of stamping technology, and in particular to a stamping die and stamping process for an explosion-proof valve mounting hole on the side wall of a battery casing. Background Technology

[0002] Lithium-ion batteries are widely used in new energy vehicles due to their high energy density, excellent cycle performance, high charging efficiency, high output power, and long service life. Lithium-ion batteries are generally packaged in aluminum casings, which are commonly in round, rectangular, or blade-shaped forms. The forming processes and molds for round and rectangular casings are relatively mature, while the forming processes and molds for blade-shaped casings are still under development.

[0003] Blade-shaped housings are generally double-through structures. A key difference between them and circular or rectangular housings is the absence of a bottom profile; both ends are open, making them commonly formed using extrusion or similar methods. Currently, mounting holes for explosion-proof valves can be designed on the smaller side face of the blade-shaped housing. Depending on the length of the housing, one or two different mounting holes can be designed on the side wall, thereby improving the safety of the battery cell.

[0004] However, because the sides of the blade-shaped housing are typically narrow, and the mounting hole is used for welding explosion-proof valves, the dimensional accuracy requirements for this mounting hole are extremely high; otherwise, welding defects can easily lead to battery cell safety issues. The forming process of this hole is complex, involving many steps. Furthermore, due to the high production volume, automated production is necessary. Maintaining stability during high-speed, mass production also presents significant challenges. This places extremely high technical demands on the forming process and the strength and precision of the mold structure. Summary of the Invention

[0005] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide a stamping die and stamping process for an explosion-proof valve mounting hole on the side wall of a battery casing, so as to solve the problem that it is difficult to set an explosion-proof valve mounting hole on the side wall of a blade-shaped battery casing in the prior art.

[0006] To achieve the above and other related objectives, a first aspect of the present invention provides a stamping die for an explosion-proof valve mounting hole on the side wall of a battery casing, comprising an upper die assembly, the upper die assembly including an upper die base, the upper die base being provided with a punching punch, a first pressing punch, and a second pressing punch; a lower die assembly including a lower die base, the lower die base being provided with a first process die core, a second process die core, and a third process die core evenly spaced on the lower die base, wherein the first process die core corresponds to the punching punch, the second process die core corresponds to the first pressing punch, the third process die core corresponds to the second pressing punch, and the first process die core is provided with a blanking hole; and a guide post assembly disposed between the upper die base and the lower die base, the upper die base being slidable up and down along the guide post assembly.

[0007] Preferably, the gap between the punch and the blanking hole on the first process die core is 0.04 mm.

[0008] Preferably, the outer contour dimension of the third process mold core is 0.1mm-0.5mm smaller than the inner contour dimension of the shell blank to be stamped.

[0009] Preferably, a pressure plate is provided on the upper mold base at a position corresponding to the mold core of the third process. The pressure plate is provided with a guide through hole, and the second pressing punch passes through the guide through hole on the pressure plate.

[0010] Preferably, the lower mold base is provided with reinforcing ribs at the bottom of the first process mold core, the second process mold core and the third process mold core.

[0011] A second aspect of the present invention provides a stamping process for a stamping die employing the aforementioned explosion-proof valve mounting hole on the side wall of a battery casing, the stamping process specifically including the following steps:

[0012] S1. Punching process: The shell blank is fed into the first process die core, and the side wall of the shell blank is punched by the punching punch to form a punching hole at a set position on the side wall of the shell blank.

[0013] S2, Pre-pressing process: The shell blank with punched holes in step S1 is sent into the second process mold core. A pre-pressing stepped flange is formed at a set position on the side wall of the shell blank by the first pressing punch. The pre-pressing stepped flange is concentric with the punched holes, and the depth of the pre-pressing stepped flange is 50%-80% of the depth of the final stepped flange to be formed.

[0014] S3, Final pressing process: The shell blank pre-pressed in step S2 is sent into the mold core of the third process. The second pressing punch is used to press the pre-pressed stepped flange again, so that the depth of the stepped flange reaches 100% of the required final stepped flange depth.

[0015] Preferably, in step S1, the first process die core is provided with a blanking hole, and the gap between the punch and the blanking hole is 0.04mm.

[0016] Preferably, in step S2, the outline of the pre-pressed stepped flange is offset inward by 0.3 mm compared to the outline of the final formed stepped flange.

[0017] Preferably, the length-to-width ratio of the cross-section of the shell blank is 5:1 to 8:1.

[0018] As described above, the stamping die and stamping process for the explosion-proof valve mounting hole on the side wall of the battery casing of the present invention have the following beneficial effects: In use, the casing blank is fed into the first process die core of the stamping die, and the casing blank is positioned by the first process die core. Then, the casing blank is punched by the punching punch on the upper die base to form a punching hole on the side wall of the casing blank. Then, the casing blank with the punched hole is fed into the second process die core, and a pre-pressed stepped flange is formed by punching the side wall of the casing blank by the first pressing punch, so that the pre-pressed stepped flange is concentric with the punching hole. The depth of the pre-pressed stepped flange is 50%-80% of the final step flange depth to be formed. Then, the pre-pressed casing blank is fed into the third process die core, and the second pressing punch is used to press again on the basis of the pre-pressed stepped flange, so that the depth of the stepped flange reaches 100% of the required final step flange depth, and thus the stamping of the explosion-proof valve mounting hole is completed. By performing two pressing operations on the stepped flange of the explosion-proof valve mounting hole, the forming quality of the mounting hole can be improved, and deformation of the blade-shaped battery casing caused by a single pressing operation can be prevented. This solves the problem of the difficulty in setting explosion-proof valve mounting holes on the side wall of the blade-shaped battery casing. Attached Figure Description

[0019] Figure 1 The diagram shows a schematic of the structure of the blade-shaped battery casing blank (with explosion-proof valve mounting holes machined on the side wall) provided by the present invention.

[0020] Figure 2 The diagram shown is a structural schematic of the explosion-proof valve mounting hole provided by the present invention.

[0021] Figure 3 The illustration provided by this invention Figure 2 Sectional view of AA.

[0022] Figure 4 The image shown is a side view of the stamping die for the explosion-proof valve mounting hole on the side wall of the battery casing provided by the present invention.

[0023] Figure 5 The diagram shows the structure of the second pressing punch and the pressing plate provided by the present invention.

[0024] Figure 6 The diagram shown is a structural schematic of the upper mold assembly provided by the present invention.

[0025] Figure 7 The diagram shown is a structural schematic of the lower mold assembly (some parts omitted) provided by the present invention.

[0026] Figure 8 The diagram shown is a structural schematic of the lower mold assembly provided by the present invention.

[0027] Figure 9 The diagram shows a three-dimensional structural schematic of the stamping die for the explosion-proof valve mounting hole on the side wall of the battery casing provided by the present invention.

[0028] Figure 10 The illustration provided by this invention Figure 9 Exploded view.

[0029] Explanation of reference numerals in the attached figures:

[0030] 10 Upper mold assembly

[0031] 11 Upper mold base

[0032] 12 Punching punch

[0033] 13 First pier press

[0034] 14 Second pier pressing head

[0035] 111 Pressure Plate

[0036] 20 Lower mold assembly

[0037] 21 Lower mold base

[0038] 22 First Process Mold Core

[0039] 23 Second process mold core

[0040] 24 Third process mold core

[0041] 211 Reinforcing Rib

[0042] 100 Shell blank

[0043] 101 punching hole

[0044] 102 Stepped Flange

[0045] 103 Explosion-proof valve mounting hole Detailed Implementation

[0046] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0047] In the description of this invention, it should be noted that, unless otherwise specified and limited, the terms "installation," "connection," and "linking" 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 a connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0048] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., used to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are used 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. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0049] Please see Figures 1 to 10 It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of the present invention. Therefore, the drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0050] Currently, lithium batteries are widely used in the new energy vehicle field due to their high energy density, excellent cycle performance, high charging efficiency, high output power, and long service life. Lithium-ion batteries are generally packaged in aluminum casings, which are commonly in the form of round, rectangular, or blade-shaped casings. The forming processes and molds for round and rectangular casings are generally mature, while the forming processes and molds for blade-shaped casings are still under continuous exploration and development.

[0051] like Figure 1 The diagram shows a schematic of a blade-shaped battery casing. It typically has a double-opening structure, meaning both the left and right ends of the casing are open. Currently, explosion-proof valves are installed on existing blade-shaped battery casings by covering the left and right ends with end caps, which results in low safety performance. With increasingly stringent safety requirements for fuel cells, there is an urgent need for molds and processes capable of machining explosion-proof valve mounting holes on the sides of the blade-shaped battery casing.

[0052] The first aspect of the present invention provides a stamping die for an explosion-proof valve mounting hole on the side wall of a battery casing, applicable to blade-shaped battery casings, such as... Figures 6 to 10 As shown, the stamping die includes an upper die assembly 10, a lower die assembly 20, and a guide post assembly. The upper die assembly 10 includes an upper die base 11, on which a punching punch 12, a first pressing punch 13, and a second pressing punch 14 are provided. The lower die assembly 20 includes a lower die base 21, on which a first process die core 22, a second process die core 23, and a third process die core 24 are provided at even intervals. The first process die core 22 corresponds to the punching punch 12 on the upper die base 11, the second process die core 23 corresponds to the first pressing punch 13 on the upper die base 11, and the third process die core 24 corresponds to the second pressing punch 14 on the upper die base 11. Specifically, the first process die core 22 is provided with a blanking hole. The guide post assembly is disposed between the upper die base 11 and the lower die base 21, and the upper die base 11 can slide up and down along the guide post assembly 30.

[0053] In use, the stamping die for the explosion-proof valve mounting hole on the side wall of the battery casing of the present invention involves feeding the casing blank 100 into the first process die core 22 of the stamping die, which positions the casing blank 100. Then, the punching punch 12 on the upper die base punches the casing blank, thereby forming a punching hole 101 on the side wall of the casing blank. The punched waste material falls from the blanking hole on the first process die core. Then, the casing blank with the punched hole 101 is fed into the second process die core 23, and the first pressing punch... 13. A pre-pressed stepped flange is formed by stamping the side wall of the shell blank, ensuring that the pre-pressed stepped flange is concentric with the punching hole 101. The depth of the pre-pressed stepped flange is 50%-80% of the depth of the final stepped flange 102 to be formed. Then, the pre-pressed shell blank is sent to the third process die core 24, and the second pressing punch 14 presses it again on the basis of the pre-pressed stepped flange, so that the depth of the stepped flange reaches 100% of the depth of the final stepped flange 102 to be formed. Thus, the stamping of the explosion-proof valve mounting hole 103 is completed. That is, by pressing the stepped flange of the explosion-proof valve mounting hole twice, the forming quality of the explosion-proof valve mounting hole can be improved, and deformation of the blade-shaped battery shell caused by single pressing can be prevented. This solves the problem that it is difficult to set the explosion-proof valve mounting hole on the side wall of the blade-shaped battery shell.

[0054] Specifically, such as Figure 8 As shown, in this embodiment, the guide post assembly 30 includes four guide posts 31, which are respectively disposed at the four corners of the lower mold base.

[0055] Furthermore, to improve the punching quality of the punching punch 12 on the blanking hole 101 and prevent burrs from being generated during punching and pointing towards the inside of the battery casing, thus avoiding the risk of scratching the battery cells inside the battery casing, preferably, in this embodiment, the gap between the punching punch 12 and the blanking hole on the first process die core 22 is 0.04mm. This structural design allows the proportion of the bright surface of the punched hole to be as high as 50% or more, meaning the punched cross-section of the hole is smoother. This improves the punching quality of the hole and avoids the impact of poor punching quality on the battery cells inside the battery casing. Further, in other optional embodiments, to further improve the punching quality, an ultra-precision punching method and die structure can be selected, ensuring that the installation tolerances of each guide of the die are within 0.005mm, i.e., improving the assembly accuracy of the die to further improve the punching quality.

[0056] Specifically, in this embodiment, the blade-shaped battery casing is made of aluminum, with a rectangular cross-section and a significant aspect ratio. Preferably, the aspect ratio of the casing blank's cross-section is 5:1 to 8:1. For example, the length of the rectangular cross-section is 150mm-900mm, and the width, i.e., the sidewall width of the blade-shaped battery casing, is 16mm-20mm.

[0057] Furthermore, in this embodiment, the punching force of the punching punch is used for CAE force analysis of the first process die core 22. The verification conclusion is that the punching of the punching punch easily causes deformation of the first process die core 22. Therefore, preferably, in this embodiment, as... Figure 4 As shown, a reinforcing rib plate 211 is provided on the lower die base 21 and at the bottom of the first process die core 22; similarly, by applying the pressing force of the first pressing punch 13 to the CAE stress analysis of the second process die core 23, it was found that the pressing force of the first pressing punch 13 easily causes the second process die core 23 to deform. Therefore, in this embodiment, a reinforcing rib plate 211 is also provided on the lower die base 21 and at the bottom of the second process die core 23; by applying the pressing force of the second pressing punch 14 to the CAE stress analysis of the third process die core 24, it was found that the pressing force of the second pressing punch 14 easily causes the third process die core 24 to deform. Therefore, in this embodiment, a reinforcing rib plate 211 is also provided on the lower die base 21 and at the bottom of the third process die core 24.

[0058] Furthermore, since the first process mold core 22, the second process mold core 23, and the third process mold core 24 are used to position the shell blank by passing the shell blank through the process mold cores, in order to prevent the first process mold core 22, the second process mold core 23, and the third process mold core 24 from scratching the inner wall of the shell blank during positioning, preferably, in this embodiment, the outer contour dimensions of the first process mold core 22, the second process mold core 23, and the third process mold core 24 are all 0.1mm-0.5mm smaller than the inner contour dimensions of the shell blank.

[0059] Furthermore, considering that the product's machining accuracy and dimensions are determined during the final pressing process, i.e., the second pressing, this process has high requirements for the positioning of the shell blank. If the positioning is off, misalignment will occur in the punched holes and the pressed stepped flange. Therefore, preferably, in this embodiment, as follows... Figure 5 and Figure 6As shown, in this embodiment, a pressure plate 111 is provided on the upper mold base 11 at a position corresponding to the third process mold core 24. The pressure plate 111 has guide holes, and the second pressing punch 14 passes through these guide holes. During operation, as the upper mold base 11 moves downwards, the pressure plate 111 first presses down on the shell blank on the third process mold core to prevent it from moving. Then, as the upper mold continues to descend, the second pressing punch 14 continues to move downwards along the guide holes on the pressure plate to press the shell blank. Therefore, the pressure plate effectively positions the shell blank, improving the processing accuracy and quality of the product.

[0060] As a preferred option, such as Figure 6 As shown, in this embodiment, pressure plates are also provided on the upper mold base 11 at positions corresponding to the first process mold core and the second process mold core, respectively. This structural design further improves the processing accuracy and quality of the shell blank in the punching and pressing processes.

[0061] Another aspect of the present invention provides a stamping process for a stamping die using the aforementioned explosion-proof valve mounting hole on the side wall of the battery casing, the stamping process specifically including the following steps:

[0062] S1. Punching process: The shell blank is fed into the first process die core, and the side wall of the shell blank is punched by the punching punch to form a punching hole at a set position on the side wall of the shell blank.

[0063] Furthermore, prior to step S1, the process includes obtaining the outline of the pre-obtained punching hole through CAE simulation, thereby punching with the simulated punching hole outline to obtain the desired outline size.

[0064] Specifically, in step S1, the first process die core is provided with a blanking hole. In order to improve the punching quality, the gap between the punch and the blanking hole on the first process die core can be 0.04mm.

[0065] S2, Pre-pressing process: The shell blank with punched holes in step S1 is sent into the second process mold core. A pre-pressing stepped flange is formed at a set position on the side wall of the shell blank by the first pressing punch. The pre-pressing stepped flange is concentric with the punched holes, and the depth of the pre-pressing stepped flange is 50%-80% of the depth of the final stepped flange to be formed.

[0066] For example, in step S2, it can be understood that if the required depth of the stepped flange 102 is 0.5mm, then the depth of the stepped flange to be pressed in this pre-pressing process is 0.25mm-0.4mm.

[0067] Specifically, in step S2, to prevent unstable feeding of the shell blank, which could cause a double-eyelid effect in the pre-upsetting and subsequent final upsetting processes, preferably, in step S2, the outline of the pre-upsetting stepped flange is offset inward (towards the punching hole outline) by 0.3mm compared to the outline of the final formed stepped flange.

[0068] S3, Final pressing process: The shell blank pre-pressed in step S2 is sent into the mold core of the third process. The second pressing punch is used to press the pre-pressed stepped flange again, so that the depth of the stepped flange reaches 100% of the required final stepped flange depth.

[0069] Furthermore, as a preferred embodiment, it may also include step S4, a fine blanking process. This process is a reserved process. It is determined whether the fourth process is needed based on the forming effect of the first three processes. If the product outline after the final upsetting of the third process meets the tolerance requirements, the fourth process is cancelled.

[0070] In summary, the beneficial effects of the stamping process for the explosion-proof valve mounting hole on the side wall of the battery casing of the present invention are the same as the beneficial effects of the stamping die described above, and therefore will not be repeated here.

[0071] In summary, the stamping die and stamping process for the explosion-proof valve mounting hole on the side wall of the battery casing of the present invention can stamp the explosion-proof valve mounting hole on the narrow side wall of the blade-shaped battery casing, solving the problem that it is difficult to set the explosion-proof valve mounting hole on the side wall of the blade-shaped battery casing, thereby improving the safety of the blade-shaped battery. Therefore, the present invention effectively overcomes the various shortcomings of the prior art and has high industrial application value.

[0072] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A stamping die for an explosion-proof valve mounting hole on the side wall of a battery casing, applied to a blade-shaped battery casing, characterized in that, include The upper mold assembly includes an upper mold base, on which a punching punch, a first pressing punch, and a second pressing punch are provided; The lower die assembly includes a lower die base, on which a first process die core, a second process die core, and a third process die core are evenly spaced. The first process die core corresponds to the punching punch, the second process die core corresponds to the first pressing punch, and the third process die core corresponds to the second pressing punch. The first process die core is provided with a blanking hole. A guide post assembly is disposed between the upper mold base and the lower mold base, and the upper mold base is capable of sliding up and down along the guide post assembly.

2. The stamping die for the explosion-proof valve mounting hole on the side wall of a battery casing according to claim 1, characterized in that, The gap between the punch and the blanking hole on the first process die core is 0.04 mm.

3. The stamping die for the explosion-proof valve mounting hole on the side wall of a battery casing according to claim 1, characterized in that, The outer contour dimensions of the mold core in the third process are 0.1mm-0.5mm smaller than the inner contour dimensions of the shell blank to be stamped.

4. A stamping die for an explosion-proof valve mounting hole on the side wall of a battery casing according to any one of claims 1-3, characterized in that, A pressure plate is provided on the upper mold base at a position corresponding to the mold core of the third process. The pressure plate is provided with a guide through hole, and the second pressing punch passes through the guide through hole on the pressure plate.

5. The stamping die for the explosion-proof valve mounting hole on the side wall of a battery casing according to claim 1, characterized in that, The lower mold base is provided with reinforcing ribs at the bottom of the first process mold core, the second process mold core, and the third process mold core.

6. A stamping process for a stamping die using the explosion-proof valve mounting hole on the side wall of a battery casing as described in any one of claims 1 to 5, characterized in that, The stamping process specifically includes the following steps: S1. Punching process: The shell blank is fed into the first process die core, and the side wall of the shell blank is punched by the punching punch to form a punching hole at a set position on the side wall of the shell blank. S2, Pre-pressing process: The shell blank with punched holes in step S1 is sent into the second process mold core. A pre-pressing stepped flange is formed at a set position on the side wall of the shell blank by the first pressing punch. The pre-pressing stepped flange is concentric with the punched holes, and the depth of the pre-pressing stepped flange is 50%-80% of the depth of the final stepped flange to be formed. S3, Final pressing process: The shell blank pre-pressed in step S2 is sent into the mold core of the third process. The second pressing punch is used to press the pre-pressed stepped flange again, so that the depth of the stepped flange reaches 100% of the required final stepped flange depth.

7. The stamping process for the explosion-proof valve mounting hole on the side wall of a battery casing according to claim 6, characterized in that, In step S1, the first process die core is provided with a blanking hole, and the gap between the punch and the blanking hole is 0.04mm.

8. The stamping process for the explosion-proof valve mounting hole on the side wall of a battery casing according to claim 6, characterized in that, In step S2, the outline of the pre-pressed stepped flange is offset inward by 0.3 mm compared to the outline of the final formed stepped flange.

9. The stamping process for the explosion-proof valve mounting hole on the side wall of a battery casing according to claim 6, characterized in that, The length-to-width ratio of the cross-section of the shell blank is 5:1 to 8:1.

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