Explosion-proof valve protection film and battery cell shell

Abstract

The utility model relates to power battery technical field relates to explosion -proof valve protection film and electric core casing, aiming at the technical problem that the existing technology's explosion -proof valve protection film because of traditional cross -shaped intersection formula air -permeable groove is easy to warp deformation, fall off failure under the positive pressure alternation environment, and fixed air -permeable groove cannot adapt to the technical problem of different air -permeable demand, the utility model provides explosion -proof valve protection film, including sheet structure base body, which is equipped with several air -permeable grooves along its thickness direction penetration, air -permeable groove is all strip groove, and is independent, not intercommunicate, also does not intersect, several strip air -permeable grooves are arranged in the radial shape with the predetermined position on the base body as the center, and the radial arrangement mode is evenly distributed or symmetrical distribution, while ensuring the air -permeability, the anti -warping capacity and structural stability are significantly improved, further, the utility model still provides a kind of electric core casing.

Description

Technical Field

[0001] This utility model relates to the field of power battery technology, specifically to an explosion-proof valve protective film and a battery cell housing. Background Technology

[0002] Currently, the safety performance of power batteries is receiving much attention. As an important safety component of lithium batteries, the explosion-proof valve is usually installed on the battery cover or casing. When the internal pressure of the battery exceeds the safety threshold, the explosion-proof valve will open rapidly to release the high-pressure gas inside, thereby preventing the battery from thermal runaway due to continuous pressure rise and reducing safety risks.

[0003] During battery manufacturing and use, explosion-proof valves are typically covered with a protective film to prevent mechanical damage, contamination, or corrosion. However, during cell manufacturing, due to process requirements (such as electrolyte injection and vacuuming), the internal space of the battery and the sealed space between the explosion-proof valve and the protective film experiences alternating positive and negative pressure environments. If this sealed space cannot quickly and effectively balance the internal and external pressure differences, the protective film may become dented, warped, or even detached. Once the protective film fails, the explosion-proof valve may be exposed to the external environment and become contaminated or corroded, affecting its normal function and ultimately causing battery safety or appearance problems.

[0004] Traditional explosion-proof valve protective membranes typically employ a cross-shaped or other intersecting structure of vent grooves to provide a certain degree of air permeability. For example, Chinese Utility Model Authorization Announcement No. CN206564278U, filed on February 14, 2017, entitled "An Explosion-proof Valve Protective Membrane," discloses a protective membrane with liquid-repellent and air-permeable slits, the slits being in the shape of an "I" (line).

[0005] At least one of the following shapes: "+", "H", "N", and "T". For example, Chinese Utility Model Authorization Announcement No. CN220400829U, application date June 27, 2023, invention title: "A Battery Explosion-Proof Protective Film, Explosion-Proof Valve Assembly, and Battery"; the disclosed battery explosion-proof protective film includes a protective film body and multiple vent holes, the vent holes being linear and penetrating both sides of the protective film body, with one end of each vent hole converging on the protective film body. However, due to the existence of intersection points, this type of vent groove has low structural strength and is prone to deformation or warping under repeated positive and negative pressure changes, leading to decreased air permeability or protective film detachment. Furthermore, the number of vent grooves in traditional designs is fixed, making it impossible to flexibly adjust according to the air permeability requirements of different battery cells, thus limiting its applicability.

[0006] Therefore, there is an urgent need for a new type of explosion-proof valve protective membrane structure that can improve the resistance to deformation while ensuring air permeability, and can flexibly adjust the air permeability level according to actual needs, so as to better meet the safety protection requirements of power batteries. Summary of the Invention

[0007] 1. The problem to be solved

[0008] In response to the technical problems of existing explosion-proof valve protective films, such as the tendency of traditional cross-shaped or other intersecting venting grooves to warp, deform, and detach under alternating positive and negative pressure environments, and the inability of fixed venting grooves to adapt to different venting requirements, this utility model provides an explosion-proof valve protective film that significantly improves anti-warping ability and structural stability while ensuring venting performance. Furthermore, this utility model also provides a battery cell housing.

[0009] 2. Technical Solution

[0010] To solve the above problems, the technical solution provided by this utility model is as follows:

[0011] The first aspect of this utility model provides an explosion-proof valve protective film, including a substrate, wherein the substrate is a sheet structure and a plurality of air-permeable grooves are provided on the substrate through the thickness direction.

[0012] The ventilation grooves are strip-shaped grooves, and the ventilation grooves are independent of each other, not connected to each other, and do not intersect each other;

[0013] The ventilation grooves are arranged radially around a predetermined position on the substrate.

[0014] According to any embodiment of the explosion-proof valve protective film of the first aspect of the present invention, the air-permeable grooves are all strip-shaped grooves; the radial arrangement is uniformly distributed or symmetrically distributed.

[0015] According to any embodiment of the first aspect of this utility model, the number of the venting grooves in the explosion-proof valve protective film is 1 to 9, which can be set according to different venting level requirements.

[0016] By limiting the number of ventilation slots to 1 to 9, the number can be flexibly adjusted according to the ventilation requirements of different battery models and usage environments. This can meet the application scenarios with high ventilation requirements while maintaining a simple structure when low ventilation requirements are met, achieving precise control of ventilation performance and improving the applicability and economy of the product.

[0017] According to any embodiment of the first aspect of the present invention, the explosion-proof valve protective film has the vent groove disposed in the central region and / or side region of the substrate.

[0018] The design allows the venting grooves to be placed in the central and / or side areas of the substrate, enabling the protective membrane to adapt to the structural layout requirements of different explosion-proof valves. The central arrangement optimizes the pressure balance effect, while the side arrangement facilitates special installation scenarios, enhancing the product's versatility and installation flexibility.

[0019] According to any embodiment of the first aspect of this utility model, the width of the venting groove in the explosion-proof valve protective film is 0.1mm to 5mm.

[0020] Limiting the width of the ventilation groove to the range of 0.1mm to 5mm ensures sufficient ventilation area for rapid pressure adjustment while avoiding a decrease in structural strength due to excessive groove width, thus achieving the best balance between ventilation performance and mechanical strength.

[0021] According to any embodiment of the first aspect of this utility model, the explosion-proof valve protective film has an elliptical or circular substrate.

[0022] The elliptical base design is more suitable for the installation space of most battery explosion-proof valves compared to the traditional circular structure, thus improving space utilization. At the same time, the elliptical contour is more conducive to uniform stress distribution, further enhancing the deformation resistance of the protective film.

[0023] The explosion-proof valve protective film according to any embodiment of the first aspect of the present invention further includes an adhesive layer applied to the annular region surrounding the substrate.

[0024] The design of setting an annular adhesive layer around the substrate ensures a firm bond between the protective film and the explosion-proof valve, while avoiding interference from the adhesive layer on the ventilated groove area, thus ensuring stable fixation without affecting the ventilated function.

[0025] According to any embodiment of the first aspect of this utility model, the thickness of the substrate of the explosion-proof valve protective film is 0.15mm to 0.25mm; and the thickness of the adhesive layer is 0.05mm to 0.2mm.

[0026] By controlling the thickness of the substrate to 0.15–0.25 mm and the thickness of the adhesive layer to 0.05–0.2 mm, the overall thickness is reduced while ensuring sufficient structural strength, thus meeting the protection requirements of the explosion-proof valve without increasing the volume and weight excessively.

[0027] According to any embodiment of the first aspect of the present invention, the explosion-proof valve protective film is made of PET, PP, PE or PI; the adhesive layer is made of 3M467 or DSTT-10M.

[0028] Using PET, PP, PE or PI as the base material, combined with 3M467 or DSTT-10M adhesive layer material, the product has excellent mechanical properties, chemical stability and bonding reliability, and can adapt to temperature changes and chemical corrosion in the battery working environment.

[0029] Preferably, the adhesive layer is further provided with release paper on the side away from the substrate.

[0030] A release paper is placed on the outside of the adhesive layer, which not only protects the adhesive layer from contamination and damage during transportation and storage, but also facilitates the operation during installation, thereby improving the product's ease of use and reliability.

[0031] The second aspect of this utility model provides a battery cell housing, including the aforementioned explosion-proof valve protective film.

[0032] 3. Beneficial effects

[0033] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0034] (1) The explosion-proof valve protective film of this utility model effectively solves the problem of easy warping and deformation of traditional intersecting venting grooves by adopting a design of mutually independent and radially uniform / symmetrically distributed strip venting grooves. The independent and non-connected structure of each venting groove significantly improves the resistance to pressure difference deformation, ensuring that the protective film remains flat and adhered even under alternating positive and negative pressure environments. At the same time, the radially arranged venting grooves can be increased or decreased in number according to actual needs to flexibly adjust the venting level. While maintaining excellent anti-fouling performance, it achieves rapid pressure balance, which protects the explosion-proof valve from pollution and corrosion, and avoids patch detachment and failure due to pressure imbalance, thereby comprehensively improving the safety and reliability of the battery.

[0035] (2) The battery cell housing of this utility model effectively solves the problem of pressure regulation failure caused by the warping of the protective film or insufficient air permeability in traditional housings by optimizing the air permeability and protection balance in the explosion-proof valve area; its radial independent air permeable groove structure can quickly balance the positive and negative pressure difference in the battery cell manufacturing process, prevent the protective film from deforming and falling off, and flexibly adjust the air permeability according to the battery design requirements to ensure the long-term stable operation of the explosion-proof valve, ultimately improving the overall sealing and safety of the housing and extending the battery service life. Attached Figure Description

[0036] Figure 1 This is a bottom view of the protective membrane structure of the explosion-proof valve in Example 1;

[0037] Figure 2 This is a top view of the protective membrane structure of the explosion-proof valve in Example 1;

[0038] Figure 3 This is a schematic diagram of the three-dimensional structure of the explosion-proof valve protective membrane in Example 1;

[0039] Figure 4 This is a bottom view of the protective membrane structure of the explosion-proof valve in Example 2;

[0040] Figure 5 This is a bottom view of the protective membrane structure of the explosion-proof valve in Example 3;

[0041] Figure 6 This is a top view of the protective membrane structure of the explosion-proof valve in Example 4;

[0042] Figure 7 This is a top view of the protective membrane structure of the explosion-proof valve in Example 5;

[0043] Figure 8 This is a top view of the protective membrane structure of the explosion-proof valve in Example 6.

[0044] In the picture:

[0045] 1. Matrix; 2. Adhesive layer; 3. Ventilation groove. Detailed Implementation

[0046] The technical solutions in the embodiments of this utility model will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0047] Example 1

[0048] The explosion-proof valve protective film in this embodiment, such as Figures 1-3 As shown, it includes a substrate 1 and an adhesive layer 2 applied to the annular region surrounding the substrate 1.

[0049] Substrate 1 is an elliptical sheet structure made of PET (polyethylene terephthalate) with a thickness of 0.2 mm. In other embodiments, substrate 1 can also be circular in shape, and its thickness can be selected within the range of 0.15 mm to 0.25 mm to meet different application requirements. The material of substrate 1 must be flat, smooth, free of burrs, material shortages, and deformation to ensure that the resulting protective film is leak-proof. Simultaneously, the outer surface of the protective film must be kept clean and free of dirt.

[0050] The substrate 1 has several permeable grooves 3 extending along its thickness. In this embodiment, there are five permeable grooves 3, all of which are strip-shaped and independent of each other, not connected to each other, and not intersecting. These permeable grooves are evenly distributed radially around the center of the substrate 1. The width of the permeable groove 3 is 1 mm and the length is 3 mm. In other embodiments, the width of the permeable groove 3 can be selected within the range of 0.1 mm to 5 mm, and the length can be adjusted according to actual needs.

[0051] Adhesive layer 2 is applied to the peripheral annular area of ​​substrate 1, with a thickness of 0.1 mm. In other embodiments, the thickness of adhesive layer 2 can be selected within the range of 0.05 mm to 0.2 mm. The material of adhesive layer 2 is 3M 467, a substrate-free double-sided adhesive made by direct coating of acrylic adhesive, which has excellent adhesion, prevents peeling, and has excellent waterproof performance. The setting of adhesive layer 2 ensures a firm bond between the protective film and the explosion-proof valve, while avoiding interference with the ventilated area, ensuring stable fixation without affecting the ventilated function. In some other embodiments, the material of adhesive layer 2 can also be DSTT-10M.

[0052] A release liner is also provided on the side of the adhesive layer 2 away from the substrate 1. The release liner is a polymer-coated waterproof kraft paper with good waterproof performance and temperature resistance. It will not wrinkle even in high humidity environments, can withstand high temperatures for a long time, and can withstand high temperatures for a short time. The release liner not only protects the adhesive layer from contamination and damage during transportation and storage, but also facilitates the operation during installation, improving the product's ease of use and reliability.

[0053] The explosion-proof valve protective film in this embodiment effectively solves the problem of warping and deformation caused by traditional intersecting venting grooves by employing an independent and radially evenly distributed strip-shaped venting groove design. The independent and non-connected structure of each venting groove significantly improves its resistance to pressure differential deformation, ensuring that the protective film remains flat and adhered even under alternating positive and negative pressure environments. Simultaneously, the radially arranged venting grooves can be increased or decreased in number to flexibly adjust the permeability level according to actual needs. This maintains excellent anti-fouling performance while achieving rapid pressure balance, protecting the explosion-proof valve from contamination and corrosion, and preventing patch detachment and failure due to pressure imbalance, thereby comprehensively improving the safety and reliability of the battery.

[0054] Furthermore, the elliptical substrate 1 design better fits the installation space of most battery explosion-proof valves compared to the traditional circular structure, improving space utilization. Simultaneously, the elliptical contour is more conducive to uniform stress distribution, further enhancing the protective film's resistance to deformation. By controlling the substrate thickness to 0.15–0.25 mm and the adhesive layer thickness to 0.05–0.2 mm, overall thinness and lightness are achieved while ensuring sufficient structural strength, meeting the protection requirements of the explosion-proof valve without adding excessive volume and weight.

[0055] The explosion-proof valve protective film of this embodiment can be applied to the cell casing and battery. It is easy to assemble and process, and can effectively prevent sharp objects from damaging the explosion-proof valve or foreign objects, dust and other objects from falling into the explosion-proof valve, thus ensuring the safety and reliability of the battery.

[0056] Example 2

[0057] The explosion-proof valve protective membrane in this embodiment is basically the same as in Embodiment 1, except for the number and layout of the venting grooves. Figure 4As shown, there are two venting grooves, symmetrically arranged in the central area of ​​the elliptical base 1. Each venting groove is a strip-shaped groove, 1mm wide and 2mm long, and each venting groove is independent, not connected to, and does not intersect with each other. This symmetrical venting groove design in the central area can optimize the pressure balance effect while ensuring air permeability, and is particularly suitable for symmetrical layout explosion-proof valve structures.

[0058] Example 3

[0059] The explosion-proof valve protective membrane in this embodiment is basically the same as in Embodiment 1, except for the number and layout of the venting grooves. Figure 5 As shown, there are four ventilation channels, symmetrically arranged in the central area of ​​the elliptical substrate 1. Each ventilation channel is a strip-shaped channel, 1mm wide and 2mm long, and each channel is independent, unconnected, and does not intersect with the others. This design further enhances the breathability while maintaining the symmetry and stability of the structure, making it suitable for applications with high breathability requirements.

[0060] Example 4

[0061] The explosion-proof valve protective membrane in this embodiment is basically the same as in Embodiment 1, except for the number and layout of the venting grooves. Figure 6 As shown, there are two venting grooves, symmetrically arranged on the side region away from the center of the elliptical base 1. Each venting groove is a strip-shaped groove, 1mm wide and 2mm long, and each venting groove is independent, not connected to, and does not intersect with each other. This side-mounted venting groove design facilitates pressure adjustment in special installation scenarios while avoiding interference with the central area of ​​the explosion-proof valve.

[0062] Example 5

[0063] The explosion-proof valve protective membrane in this embodiment is basically the same as in Embodiment 1, except for the number and layout of the venting grooves. Figure 7 As shown, there are four ventilation channels, symmetrically arranged on the side area away from the center of the elliptical base 1. Each ventilation channel is a strip-shaped channel, 1mm wide and 2mm long, and each channel is independent, unconnected, and does not intersect with each other. This design provides more ventilation channels in the side area, further enhancing ventilation performance, and is suitable for applications requiring pressure regulation in the side area.

[0064] Example 6

[0065] The explosion-proof valve protective membrane in this embodiment is basically the same as in Embodiment 1, except for the number and layout of the venting grooves. Figure 8As shown, there are six ventilation channels, symmetrically arranged on the side region away from the center of the elliptical base 1. Each ventilation channel is a strip-shaped channel, 1mm wide and 2mm long, and each channel is independent, unconnected, and does not intersect with others. This design provides a higher level of breathability, making it particularly suitable for applications with extremely high breathability requirements, while maintaining structural symmetry and stability.

[0066] This invention demonstrates diverse designs for the protective membrane of explosion-proof valves through multiple embodiments. Embodiments 1-6, by adjusting the number and position of the venting grooves, meet the needs of different venting levels and installation scenarios. This design not only optimizes pressure balance and venting performance but also enhances the versatility and adaptability of the protective membrane, ensuring effective protection of the explosion-proof valve in various application scenarios and improving battery safety and reliability.

Claims

1. An explosion-proof valve protective film, comprising a substrate (1), characterized in that: The substrate (1) is a sheet structure, and the substrate (1) is provided with a plurality of breathable grooves (3) that penetrate along its thickness direction; The ventilation groove (3) is a strip-shaped groove, and the ventilation grooves (3) are independent of each other, do not communicate with each other, and do not intersect each other; Several of the ventilation grooves (3) are arranged radially around a predetermined position on the substrate (1).

2. The explosion-proof valve protective membrane according to claim 1, characterized in that: The ventilation grooves (3) are all strip-shaped grooves; the radial arrangement is uniform or symmetrical.

3. The explosion-proof valve protective membrane according to claim 1, characterized in that: The number of the ventilation slots (3) is 1 to 9, which can be set according to different ventilation level requirements.

4. The explosion-proof valve protective membrane according to claim 1, characterized in that: The ventilation groove (3) is provided in the central region and / or side region of the substrate (1).

5. The explosion-proof valve protective membrane according to claim 1, characterized in that: The width of the ventilation groove (3) is 0.1mm to 5mm.

6. The explosion-proof valve protective membrane according to any one of claims 1-5, characterized in that: The substrate (1) is elliptical or circular.

7. The explosion-proof valve protective membrane according to claim 6, characterized in that: It also includes an adhesive layer (2) applied to the annular region surrounding the substrate (1).

8. The explosion-proof valve protective membrane according to claim 7, characterized in that: The thickness of the substrate (1) is 0.15 mm to 0.25 mm; the thickness of the adhesive layer (2) is 0.05 mm to 0.2 mm.

9. The explosion-proof valve protective membrane according to claim 7, characterized in that: The substrate (1) is made of PET, PP, PE or PI; the adhesive layer (2) is made of 3M467 or DSTT-10M.

10. A battery cell casing, characterized in that: Includes the explosion-proof valve protective film as described in any one of claims 1-9.

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