Integrated explosion-proof valve mushroom head processing technology and double integrated battery cover plate

Abstract

The application discloses an integrated explosion-proof valve mushroom head processing technology and a double-integrated battery cover plate. The processing technology comprises the following steps: rough stretching, stretching the top cover plate at the position of the explosion-proof valve based on the aluminum top cover plate, so that the edge position of the explosion-proof valve maintains a thickness of 0.45-0.55 mm, the middle part of the explosion-proof valve maintains a thickness of 2-2.5 mm, and the stretching height of the middle part is 2 times the height of the base body of the explosion-proof valve; spherical surface stretching, so that the inner surface and the outer surface of the middle part form a hemispherical structure away from each other; mushroom head initial shaping, extruding the outer surface of the middle part by using a convex die, and simultaneously supporting the inner surface of the middle part by using a concave die made of elastic material, so that the explosion-proof valve is extruded into a mushroom head structure, the top surface of the mushroom head structure is a plane structure, and an elastic allowance deformation space is arranged on the outer circumferential side of the mushroom head structure; mushroom head final shaping, the shape of the explosion-proof valve is punched out by continuous stretching and stamping, and then the middle position is marked by cold heading, so that the personnel, equipment and process flow can be greatly simplified.

Description

Technical Field

[0001] This invention relates to the field of battery cover technology, and in particular to the processing technology of an integrated explosion-proof valve mushroom head and a double integrated battery cover. Background Technology

[0002] In the cover plate of new energy batteries, the connecting piece is usually an independent component. It is first connected to the tab by ultrasonic welding, and then connected to the post by laser welding. The process is relatively complicated, which increases the labor time and material costs of the cell factory.

[0003] In addition, the explosion-proof valve on the battery cover is pre-stamped and then welded to the top cover using laser welding technology. This requires the entire battery to have a helium permeability of less than 1.0 x 10-7 Pa·m3 / s, and the explosion-proof valve to open at the notch to passively release pressure when the internal pressure is 0.6 ± 0.2 MPa, in order to prevent the battery from overheating and causing excessive internal pressure that could lead to an explosion. This requires a lot of personnel, equipment, materials, and time, making it less cost-effective. Summary of the Invention

[0004] One advantage of this invention is that it provides a one-piece explosion-proof valve mushroom head processing technology and a double-integrated battery cover plate, wherein the explosion-proof valve and the top cover plate are integrally stamped and stretched. Although the design requirements for the hardware mold and the top cover plate are more stringent, it can greatly simplify personnel, equipment, and assembly processes for assembly production, thereby saving costs. In addition, this one-piece explosion-proof valve mushroom head can ensure that when the internal pressure changes slightly due to changes in the battery cell temperature, the explosion-proof valve can have a certain range of elastic deformation space, which will not cause changes or damage to the explosion-proof valve markings that play a safety role, thus improving safety and reliability.

[0005] Specifically, in the first aspect, the present invention provides a processing technology for an integrated explosion-proof valve mushroom head, comprising the following steps:

[0006] Coarse stretching: Based on the aluminum top cover plate, stretch the top cover plate at the position of the explosion-proof valve so that the edge of the explosion-proof valve maintains a thickness of 0.45-0.55mm and the middle part of the explosion-proof valve maintains a thickness of 2-2.5mm, and the stretching height of the middle part is twice the height of the explosion-proof valve base.

[0007] Spherical stretching causes the inner and outer surfaces of the middle portion to form a hemispherical structure that is far apart from each other;

[0008] The mushroom head initial shaping involves using a punch to press the outer surface of the middle part, while the die is designed as an elastic material to support the inner surface of the middle part, thus extruding the explosion-proof valve into a mushroom head structure. The top surface of the mushroom head structure is a planar structure, and the outer periphery of the mushroom head structure is provided with an elastic allowance deformation space.

[0009] After the mushroom head is shaped, the shape of the explosion-proof valve is formed by continuous stretching and stamping, and then the middle position is marked by cold heading process.

[0010] According to an embodiment of the present invention, the spherical stretching includes primary spherical stretching and secondary spherical stretching. The primary spherical stretching involves stretching the middle portion to form a complete hemispherical structure on the outer surface of the middle portion and forming a first inner hemispherical structure on the inner surface of the middle portion near the center. The secondary spherical stretching involves stretching the middle portion while maintaining the inherent structure of the outer surface of the middle portion, and stretching the inner surface of the middle portion into a second inner hemispherical structure symmetrical to the outer surface of the middle portion. The diameter of the second inner hemispherical structure is larger than that of the first inner hemispherical structure, and the thickness of the outer portion of the second inner hemispherical structure is smaller than that of the outer portion of the first inner hemispherical structure.

[0011] According to one embodiment of the present invention, the initial shaping and subsequent shaping of the mushroom head are performed by continuous stamping using a continuous die, and the inner and outer surfaces of the middle part are stamped to form an inner columnar boss and an outer columnar boss respectively by always maintaining an obtuse angle deformation.

[0012] According to one embodiment of the present invention, after cold heading is used to create a groove in the middle position, the final stretching and stamping process is repeated once.

[0013] Secondly, the present invention also provides a dual-integrated battery cover, including a top cover, an explosion-proof valve, and electrode post assemblies symmetrically arranged at both ends of the top cover. The explosion-proof valve and the top cover are integrally stretched and formed by the aforementioned integrated explosion-proof valve mushroom head processing technology. The electrode post assembly includes an electrode post, an upper plastic, a lower plastic, a connecting piece, and an electrode block arranged sequentially from the top end to the bottom end of the top cover. The upper plastic, the lower plastic, the connecting piece, and the electrode block are coaxially provided with through holes that cooperate with the electrode post, and the connecting piece and the top cover are riveted together to form an integral structure.

[0014] According to an embodiment of the present invention, the explosion-proof valve has an outer ear located on the outer side near the top of the middle portion. The elastic allowance deformation space is located inside the outer ear and communicates with the inner cavity of the explosion-proof valve. The elastic allowance space extends obliquely from the middle portion outward away from the inner columnar boss, and the angle of inclination relative to the top cover plate is 25°-45°. The top of the outer ear protrudes 0.08-0.13mm beyond the top of the outer columnar boss.

[0015] These and other objects, features and advantages of the present invention will become fully apparent from the following detailed description. Attached Figure Description

[0016] Figure 1 A schematic flowchart illustrating the processing technology of the mushroom head of an integrated explosion-proof valve according to a preferred embodiment of this application is shown.

[0017] Figure 2 A cross-sectional view of the mushroom head of the integrated explosion-proof valve in this application is shown.

[0018] Figure 3 An exploded view of a preferred embodiment of the dual-integrated battery cover of this application is shown. Detailed Implementation

[0019] The following description is intended to disclose the present invention and enable those skilled in the art to implement it. The preferred embodiments described below are merely examples, and other obvious variations will occur to those skilled in the art. The basic principles of the invention defined in the following description can be applied to other embodiments, modifications, improvements, equivalents, and other technical solutions that do not depart from the spirit and scope of the invention.

[0020] Those skilled in the art should understand that, in the disclosure of this specification, the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the present 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. Therefore, the above terms should not be construed as limiting the present invention.

[0021] It is understood that the term "a" should be understood as "at least one" or "one or more", that is, in one embodiment, the number of an element can be one, while in another embodiment, the number of the element can be multiple, and the term "a" should not be understood as a limitation on the number.

[0022] refer to Figure 1 and Figure 2 A preferred embodiment of the present invention provides a processing method for an integrated explosion-proof valve mushroom head, which will be described in detail below. The processing method for the integrated explosion-proof valve mushroom head includes the following steps:

[0023] Coarse stretching: Based on the aluminum top cover plate 10, stretch the top cover plate 10 at the position of the explosion-proof valve so that the edge position 21 of the explosion-proof valve 20 maintains a thickness of 0.45-0.55mm, for example, 0.5mm, and the middle part 22 of the explosion-proof valve 20 maintains a thickness of 2-2.5mm, for example, 2mm, to ensure that excess material flows to the middle, and the stretching height of the middle part 22 is twice the height of the explosion-proof valve 20 base (i.e., the top cover plate 10) to ensure that there is enough material when the outer ear 24 is turned outward and the height decreases synchronously during the subsequent shaping process;

[0024] Spherical stretching causes the inner and outer surfaces of the intermediate portion 22 to form mutually distant hemispherical structures;

[0025] The initial shaping of the mushroom head involves using a punch to press the outer surface of the middle part 22, while the die is designed to be made of an elastic material. During the punch pressing, the inner surface of the middle part 22 is supported, thus extruding the explosion-proof valve 20 into a mushroom head structure. This solves the problem of material flow issues caused by large quantities of material, while also allowing the material to flow in the desired direction to form the required mushroom head structure. This avoids stress concentration caused by thermal effects during subsequent welding. The top surface of the mushroom head structure is a planar structure, and the outer periphery of the mushroom head structure is provided with an elastic deformation space. Thus, when the temperature of the battery cell in the battery cover changes and causes a slight change in internal pressure, the explosion-proof valve 20 can generate a certain range of elastic deformation space. This prevents changes or even damage to the explosion-proof valve's scoring 23 before the explosion requirement is met, thereby greatly improving the safety and reliability of the explosion-proof valve 20 and significantly extending its service life.

[0026] After the mushroom head is shaped, the explosion-proof valve 20 is formed by continuous stretching and stamping. Then, a cold forging process is used to create a central groove 23. During the cold forging of groove 23, the mushroom head structure of the explosion-proof valve has enough space to absorb the stress during the groove 23. This reduces the impact of stress on the explosion-proof valve's breathing burst value in the early stages of production, thereby ensuring the stability and consistency of the explosion-proof valve.

[0027] At the beginning of the processing, the top cover plate 10 is 2mm thick, and the middle part 22 of the explosion-proof valve 20 is 2mm thick. In contrast, conventional pleated explosion-proof valves use 0.5mm thick plates, which are consistent with the requirements of explosion-proof valve 20. This not only results in low material flow during molding, but also in small deformation space, which can easily cause stress concentration in the notches 23, thus having an adverse effect on the breath burst value. In contrast, the mushroom head structure of the integrated explosion-proof valve has a large deformation space when notches 23 are made, which facilitates stress release. This can have a positive and beneficial effect on the breath burst value, making the integrated explosion-proof valve more reliable and safer.

[0028] In one embodiment, the spherical stretching includes primary spherical stretching and secondary spherical stretching. The primary spherical stretching involves stretching the middle portion 22 to form a complete hemispherical structure on its outer surface and to form a first inner hemispherical structure 221 on its inner surface near the center. The secondary spherical stretching involves stretching the middle portion 22 while maintaining the inherent structure of its outer surface, stretching its inner surface into a second inner hemispherical structure 222 that is symmetrical to its outer surface. The diameter of the second inner hemisphere structure 222 is larger than the diameter of the second inner hemisphere structure 221, and the thickness of the outer part of the second inner hemisphere structure 222 is smaller than the thickness of the outer part of the first inner hemisphere structure 221. This allows for the gradual stretching of the required inner and outer spherical structures, while also allowing for the preparation or processing of the sheet material for the subsequent shaping of the outer ear portion 24 without compromising the structural strength of the sheet material. The outer ear portion 24 is the key to providing elastic allowance and deformation space, which can greatly protect the explosion-proof valve scratch 23 from changes or damage when the internal pressure changes slightly due to changes in the cell temperature.

[0029] In one embodiment, the initial and subsequent shaping of the mushroom head are performed using a continuous die stamping method. The inner and outer surfaces of the middle part 22 are stamped to form an inner columnar boss 223 and an outer columnar boss 224, respectively, while maintaining an obtuse angle deformation. This is to avoid cracking of the sheet metal during the stamping process, ensure the continuity of stamping, and thus ensure production efficiency.

[0030] In one embodiment, the middle portion 22 of the explosion-proof valve 20 is provided with an outer ear 24 near the top. The elastic allowance deformation space is located inside the outer ear 24 and communicates with the inner cavity of the explosion-proof valve 20. The elastic allowance space extends obliquely from the middle portion 22 outward away from the inner columnar boss 223, and the angle of inclination relative to the top cover plate 10 is 25°-45°. The top of the outer ear 24 protrudes 0.08-0.13mm from the top of the outer columnar boss 224. This ensures that the elastic allowance deformation space is kept within a suitable elastic deformation range. It prevents the quality of the explosion-proof valve 20 from being affected by an excessively large elastic allowance space (i.e., an inclination angle greater than 45°), and also prevents the explosion-proof valve from failing to protect the explosion-proof valve score 23 when the internal pressure changes due to changes in cell temperature (i.e., an inclination angle less than 25°).

[0031] In one embodiment, after cold heading to create the center mark 23, the final stretching and stamping process is repeated once more. That is, after continuous stamping using a progressive die, for example, after seven shaping processes followed by cold heading to create the center mark 23, and then repeating the seventh shaping process, this prevents issues such as inaccurate shaping dimensions or the cold heading mark 23 affecting the product's inherent dimensions, thus providing further assurance to ensure product quality.

[0032] Secondly, combining Figure 3 The present invention also provides a dual-integrated battery cover, including a top cover 10, an explosion-proof valve 20, and electrode post assemblies symmetrically arranged at both ends of the top cover 10. The explosion-proof valve 20 and the top cover 10 are integrally stretched and formed using the aforementioned integrated explosion-proof valve mushroom head processing technology. The electrode post assembly includes an electrode post 31, an upper plastic 32, a lower plastic 33, a connecting piece 34, and an electrode block 35 arranged sequentially from the top to the bottom of the top cover 10. The upper plastic 32, the lower plastic 33, and the connecting piece 34 are further defined as follows: The connecting piece 34 and the electrode block 35 are coaxially provided with through holes that cooperate with the electrode post 31. The connecting piece 34 and the top cover plate 10 are integrated into a single structure by means of reverse riveting. Thus, the connecting piece 34 is added at the beginning of the design of the top cover plate 10, which can save the process of laser welding the connecting piece 34 and the electrode post 31 during the battery cell assembly process, thereby saving costs. The reverse riveting means that the connecting piece 34 is riveted to the top cover plate 10 from the back of the top cover plate 10, that is, the side away from the electrode post 31, in the opposite direction.

[0033] Furthermore, the technical solution and corresponding technical effects of the outer ear portion 24 in the dual integrated battery cover can be found in the aforementioned embodiments, and will not be repeated here.

[0034] Those skilled in the art should understand that the embodiments of the present invention described above and shown in the accompanying drawings are merely examples and do not limit the invention. The advantages of the present invention have been fully and effectively realized. The functional and structural principles of the present invention have been demonstrated and explained in the embodiments; any variations or modifications can be made to the implementation of the present invention without departing from these principles.

Claims

1. The processing technology for an integrated explosion-proof valve mushroom head, characterized in that: Includes the following steps: Coarse stretching: Based on the aluminum top cover plate, stretch the top cover plate at the position of the explosion-proof valve so that the edge of the explosion-proof valve maintains a thickness of 0.45-0.55mm and the middle part of the explosion-proof valve maintains a thickness of 2-2.5mm, and the stretching height of the middle part is twice the height of the explosion-proof valve base. Spherical stretching causes the inner and outer surfaces of the middle portion to form a hemispherical structure that is far apart from each other; The mushroom head initial shaping involves using a punch to press the outer surface of the middle part, while the die is designed as an elastic material to support the inner surface of the middle part, thus extruding the explosion-proof valve into a mushroom head structure. The top surface of the mushroom head structure is a planar structure, and the outer periphery of the mushroom head structure is provided with an elastic allowance deformation space. After the mushroom head is shaped, the shape of the explosion-proof valve is formed by continuous stretching and stamping, and then the middle position is marked by cold heading process; The mushroom head is initially shaped and then shaped using a continuous die stamping method. The inner and outer surfaces of the middle part are stamped to form an inner columnar boss and an outer columnar boss, respectively, while maintaining an obtuse angle deformation. The middle part is provided with an outer ear near the top. The elastic allowance deformation space is located inside the outer ear and is connected to the inner cavity of the explosion-proof valve. The elastic allowance deformation space extends obliquely from the middle part outward away from the inner columnar boss, and the angle of inclination relative to the top cover plate is 25°-45°. The top of the outer ear protrudes 0.08-0.13mm from the top of the outer columnar boss.

2. The processing technology for the integrated explosion-proof valve mushroom head as described in claim 1, characterized in that, The spherical stretching includes primary spherical stretching and secondary spherical stretching. The primary spherical stretching involves stretching the middle portion to form a complete hemispherical structure on the outer surface of the middle portion and forming a first inner hemisphere structure near the center on the inner surface of the middle portion. The secondary spherical stretching involves stretching the middle portion while maintaining the inherent structure of the outer surface of the middle portion, and stretching the inner surface of the middle portion into a second inner hemisphere structure that is symmetrical to the outer surface of the middle portion. The diameter of the second inner hemisphere structure is larger than the diameter of the first inner hemisphere structure, and the thickness of the outer portion of the second inner hemisphere structure is smaller than the thickness of the outer portion of the first inner hemisphere structure.

3. The processing technology for the integrated explosion-proof valve mushroom head as described in claim 1, characterized in that, After cold heading to create the center mark, repeat the final stretching and stamping process once more.

4. A dual-integrated battery cover, characterized in that, The device includes a top cover plate, an explosion-proof valve, and pole post assemblies symmetrically arranged at both ends of the top cover plate. The explosion-proof valve and the top cover plate are integrally stretched and formed by the mushroom head processing technology of the integrated explosion-proof valve as described in claim 1 or 3. The pole post assembly includes a pole post, an upper plastic, a lower plastic, a connecting piece, and an electrode block arranged sequentially from the top end of the top cover plate. The upper plastic, the lower plastic, the connecting piece, and the electrode block are coaxially provided with through holes that cooperate with the pole post. The connecting piece and the top cover plate are riveted together to form an integral structure.

5. The dual integrated battery cover as described in claim 4, characterized in that, The explosion-proof valve has an outer ear located on the outer side of the middle part near the top. The elastic allowance deformation space is located inside the outer ear and is connected to the inner cavity of the explosion-proof valve. The elastic allowance deformation space extends obliquely from the middle part outward away from the inner columnar boss, and the angle of inclination relative to the top cover plate is 25°-45°. The top of the outer ear protrudes 0.08-0.13mm from the top of the outer columnar boss.

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