Battery cover plate and battery assembly

Abstract

The embodiment of the application provides a battery cover plate and a battery assembly, and belongs to the technical field of batteries. The battery cover plate comprises a cover plate main body, a fixing structure, at least one convex structure and a plastic layer. The accommodating groove formed on the side surface of the fixing structure through the convex structure provides a physical embedding space for the plastic layer, so that the plastic material forms an anchoring effect with the side wall of the convex structure during injection molding. The anchoring effect significantly enhances the connection strength of the plastic layer and the fixing structure through the interfacial friction force and embedding resistance between the plastic layer and the convex structure. The design of the accommodating groove of the convex structure increases the contact area between the plastic layer and the fixing structure, disperses the external force action path, reduces the stress concentration risk, further improves the connection stability, realizes the high-strength connection between the plastic layer and the fixing structure, and solves the problem that the plastic layer is prone to peeling or falling off.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to a battery cover and battery assembly. Background Technology

[0002] With the popularization of new energy vehicles, lithium batteries, as the core component of power sources, have become the focus of industry attention in terms of safety, energy density, and cost control. Square batteries, due to their compact structure, high energy density, and mature packaging technology, have become one of the mainstream battery forms. In battery modules, the cover plate, as a key component connecting the battery body to the external circuitry, must undertake multiple functions, including fixing the terminals, sealing and protecting, and providing mechanical support.

[0003] Existing square lithium battery covers typically employ a split-structure design, with core components including a top cover, terminal posts, and a fixing structure. The top cover has pre-installed mounting holes for the terminal posts, which are positioned and secured by the fixing structure. The fixing structure is usually a ring-shaped metal piece that surrounds the outside of the terminal post and is bent inward through a riveting process, forming a mechanical engagement with the surface of the terminal post for fixation. To enhance sealing performance, a plastic layer is injection-molded onto the outside of the fixing structure, and this plastic layer is bonded to the fixing structure using an adhesive.

[0004] However, the connection method between the plastic layer and the fixed structure in the existing technology has defects. The adhesive relies only on intermolecular forces to achieve bonding, and its adhesion and durability are insufficient. Especially under high temperature, vibration or long-term use conditions, the plastic layer is prone to peeling or falling off, which leads to the failure of the electrode fixing, and then causes a decrease in sealing performance, electrolyte leakage or even short circuit risk. Utility Model Content

[0005] This application provides a battery cover and battery assembly to solve the problem of easy peeling or detachment of the plastic layer.

[0006] In a first aspect, a battery cover includes:

[0007] Cover plate body;

[0008] A fixing structure is provided on the cover plate body; the fixing structure is used to fix the pole post.

[0009] At least one protruding structure is provided on the side of the fixing structure; the gap between the protruding structure and the cover plate body forms a receiving groove;

[0010] A plastic layer covers the outer side of the fixing structure, and a portion of the plastic layer is embedded in the receiving groove.

[0011] In one possible implementation, the protrusion structure is an annular protrusion, which is disposed on the outer periphery of the fixing structure.

[0012] In one possible implementation, when there are multiple annular protrusions, the multiple annular protrusions are spaced apart along the axial direction of the fixed structure.

[0013] In one possible implementation, the annular protrusion is wavy in shape, and the wavy protrusion undulates periodically along the outer periphery of the fixed structure.

[0014] In one possible implementation, the protrusion structure is a square protrusion; a plurality of the square protrusions are spaced apart along the circumferential direction of the fixed structure.

[0015] In one possible implementation, the protruding structure and the fixing structure are integrally formed.

[0016] In one possible implementation, the extension length of the protrusion structure away from the fixed structure is less than or equal to one-third of the thickness of the plastic layer and greater than or equal to one-quarter of the thickness of the plastic layer.

[0017] In one possible implementation, it also includes:

[0018] A sealing ring is disposed between the pole post and the fixing structure, and the sealing ring is compressed by the riveting process of the fixing structure.

[0019] In one possible implementation, it also includes:

[0020] An elastic element is disposed within the receiving groove; the plastic layer is embedded within the receiving groove via the elastic element.

[0021] Secondly, this application provides a battery assembly, including a battery body and a battery cover plate as described in the second aspect, disposed on the battery body.

[0022] This application provides a battery cover and battery assembly. The battery cover includes a cover body, a fixing structure, at least one protruding structure, and a plastic layer. A receiving groove formed on the side of the fixing structure by the protruding structure provides a physical embedding space for the plastic layer, allowing the plastic material to form an anchoring effect with the sidewall of the protruding structure during injection molding. This anchoring effect significantly enhances the connection strength between the plastic layer and the fixing structure through interfacial friction and embedding resistance between the plastic layer and the protruding structure. Compared with traditional bonding methods, mechanical interlocking avoids the risk of adhesive aging or failure, thus effectively preventing the plastic layer from detaching due to vibration, temperature changes, or long-term use. The receiving groove design of the protruding structure increases the contact area between the plastic layer and the fixing structure, disperses the path of external force, reduces the risk of stress concentration, further improves connection stability, achieves a high-strength connection between the plastic layer and the fixing structure, and solves the problem of easy peeling or detachment of the plastic layer. Attached Figure Description

[0023] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0024] Figure 1 A schematic diagram of the overall structure of the battery cover provided in this application;

[0025] Figure 2 for Figure 1 Enlarged view of point A in the middle.

[0026] Figure label:

[0027] 10. Cover plate body; 20. Pole post;

[0028] 100. Fixed structure;

[0029] 200. Raised structure;

[0030] 300, Plastic layer;

[0031] 400. Sealing ring.

[0032] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0033] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0034] This application relates to the mechanical structure design of a square battery cover, primarily used in lithium-ion battery packs for new energy vehicles, energy storage systems, and power tools. With the global energy structure transformation and the promotion of environmental policies, the new energy vehicle market is experiencing explosive growth. Lithium-ion batteries, as their core power source, place higher demands on the safety, stability, and cost control of battery packs. In battery packs, the cover, as a key component connecting the battery module to the external system, must simultaneously fulfill multiple functions, including terminal fixing, sealing and protection, mechanical strength support, and process simplification. Traditional battery covers typically use a riveting process to fix the terminals to the cover body, and then inject a plastic layer onto the outside of the fixing structure to enhance sealing. However, in practical applications, the adhesion strength between the plastic layer and the fixing structure is insufficient, easily leading to detachment due to vibration, temperature changes, or long-term use, which in turn causes the terminals to loosen or even fall off, directly affecting the electrical connection safety and mechanical stability of the battery pack. Furthermore, the complex riveting process and plastic layer bonding steps increase production costs and process complexity, reducing production efficiency and yield. Therefore, developing a battery cover with a simplified structure, optimized process, and guaranteed sealing and mechanical strength is a technical challenge that the new energy battery industry urgently needs to solve.

[0035] Existing square battery covers typically consist of three parts: a cover body, a fixing structure, and terminal posts. The fixing structure (such as a ring-shaped metal piece) is mounted on the cover body and is secured to the pre-installed mounting holes of the terminal posts using a riveting process. Specifically, the inner side of the fixing structure surrounds the terminal posts, while the outer side is riveted and bent to abut against the cover body, thus achieving mechanical fixation of the terminal posts. To enhance sealing, a plastic layer is typically injection-molded onto the outer side of the fixing structure, and this plastic layer is bonded to the surface of the fixing structure using an adhesive.

[0036] However, the connection method between the plastic layer and the fixed structure in the existing technology has defects. The adhesive relies only on intermolecular forces to achieve bonding, and its adhesion and durability are insufficient. Especially under high temperature, vibration or long-term use conditions, the plastic layer is prone to peeling or falling off, which leads to the failure of the electrode fixing, and then causes a decrease in sealing performance, electrolyte leakage or even short circuit risk.

[0037] Starting with the problems of insufficient adhesive strength, complex processes, and high costs in existing technologies for plastic layers, the applicant proposed an innovative approach to replace adhesive bonding with a mechanical structure design. First, addressing the issue of easy detachment of the plastic layer, the applicant analyzed that the root cause of adhesive failure is the lack of a physical locking structure. Therefore, the applicant considered creating a raised structure on the side of the fixing structure to form a receiving groove, thereby achieving mechanical interlocking of the plastic layer. Second, to simplify the process, the applicant designed the raised structure and the fixing structure to be integrally molded or fixed by welding / adhesion, avoiding additional injection molding and bonding steps. Finally, by optimizing the shape (e.g., annular, wavy, or square protrusions) and size (e.g., the extension length does not exceed one-third of the plastic layer thickness), the feasibility of mechanical interlocking force and plastic layer injection molding process was balanced. Ultimately, this technical solution significantly improves the connection strength by replacing adhesive bonding with mechanical interlocking, while optimizing the process flow, achieving a dual improvement in cost and performance.

[0038] The technical solution of this application and how the technical solution of this application solves the above-mentioned technical problems are described in detail below with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments. The embodiments of this application will now be described with reference to the accompanying drawings.

[0039] like Figure 1 and Figure 2 As shown, in a first aspect, embodiments of this application provide a battery cover, including a cover body 10, a fixing structure 100, at least one protruding structure 200, and a plastic layer 300; the fixing structure 100 is disposed on the cover body 10; the fixing structure 100 is used to fix the terminal post 20; the protruding structure 200 is disposed on the side of the fixing structure 100; a receiving groove is formed by the gap between the protruding structure 200 and the cover body 10; the plastic layer 300 covers the outer side of the fixing structure 100, and a portion of the plastic layer 300 is embedded in the receiving groove.

[0040] It should be noted that the cover body 10 refers to the base structure of the battery cover, used to support the fixing structure 100 and other functional components, such as a plate-like structure made of metal or composite materials. The fixing structure 100 refers to the mechanical structure used to fix the terminal post 20, such as a ring-shaped, rectangular, or other geometrically shaped metal part. The protruding structure 200 refers to a physical protrusion provided on the side of the fixing structure 100, such as a ring-shaped, wavy, or square protrusion, used to form a mechanical engagement with the plastic layer 300. The receiving groove refers to the groove-like structure formed by the gap between the protruding structure 200 and the cover body 10, used to receive part of the material of the plastic layer 300. The plastic layer 300 refers to a sealing material layer formed by injection molding, such as polyurethane, silicone, or other thermoplastic materials, used to enhance the sealing between the fixing structure 100 and the terminal post 20.

[0041] In the manufacturing process of the battery cover, the terminal post 20 is first pre-installed into the fixing structure 100 of the cover body 10. Then, the fixing structure 100 is bent towards the terminal post 20 through a riveting process, forming a mechanical fixation. When the plastic layer 300 is injection molded onto the outside of the fixing structure 100, the plastic material flows under high temperature and pressure, and achieves mechanical engagement through the receiving groove formed by the gap between the protruding structure 200 and the cover body 10. Specifically, part of the material of the plastic layer 300 fills the receiving groove during the injection molding process, forming a physical lock with the sidewall of the protruding structure 200. The shape and position of the protruding structure 200 determine the geometric characteristics of the receiving groove, thereby controlling the contact area and mechanical engagement force between the plastic layer 300 and the fixing structure 100. This structural design does not rely on adhesives; the sealing and mechanical fixing functions of the fixing structure 100 are achieved solely through the physical interlocking of the plastic layer 300 and the receiving groove.

[0042] This application directly solves the problem of insufficient connection strength between the plastic layer 300 and the fixed structure 100 in the prior art by using a mechanical interlocking design between the protruding structure 200 and the plastic layer 300. Specifically, the receiving groove formed by the protruding structure 200 on the side of the fixed structure 100 provides a physical embedding space for the plastic layer 300, enabling the plastic material to form an anchoring effect with the sidewall of the protruding structure 200 during injection molding. This anchoring effect significantly enhances the connection strength between the plastic layer 300 and the fixed structure 100 through the interfacial friction and embedding resistance between the plastic layer 300 and the protruding structure 200. Compared with traditional bonding methods, mechanical interlocking avoids the risk of adhesive aging or failure, thereby effectively preventing the plastic layer 300 from falling off due to vibration, temperature changes, or long-term use. In addition, the receiving groove design of the protruding structure 200 increases the contact area between the plastic layer 300 and the fixed structure 100, disperses the path of external force, reduces the risk of stress concentration, and further improves the connection stability. Through this technical means, this application achieves a high-strength connection between the plastic layer 300 and the fixed structure 100 without adding any additional process steps, while simplifying the manufacturing process and reducing production costs.

[0043] Furthermore, the protrusion structure 200 is an annular protrusion, which is located on the outer periphery of the fixing structure 100. An annular protrusion refers to a protrusion structure 200 continuously distributed along the outer periphery of the fixing structure 100, such as a circular, elliptical, or other closed-shaped protrusion. The outer periphery of the fixing structure 100 refers to the outer edge region of the fixing structure 100, used to form a mating relationship with the pole post 20 and the plastic layer 300.

[0044] The annular protrusions are distributed along the outer periphery of the fixed structure 100, forming a continuous annular structure in the receiving groove. During injection molding, the plastic layer 300 flows along the outer side of the fixed structure 100, and a continuous mechanical engagement is formed between the sidewalls of the annular protrusions and the plastic layer 300 through interfacial friction. This design enhances the connection strength between the plastic layer 300 and the fixed structure 100 through the continuity of the annular structure, while ensuring that the plastic layer 300 uniformly covers the outer surface of the fixed structure 100.

[0045] The continuous distribution of annular protrusions enables full-circumferential mechanical engagement between the plastic layer 300 and the fixed structure 100, significantly improving the uniformity of connection strength and reducing the risk of local stress concentration, thereby further enhancing the long-term stability of the plastic layer 300.

[0046] Specifically, when there are multiple annular protrusions, the multiple annular protrusions are spaced apart along the axial direction of the fixing structure 100. The axial direction refers to the extension direction of the fixing structure 100 along the installation direction of the pole post 20. Spaced apart means that the multiple annular protrusions are distributed at a certain distance in the axial direction.

[0047] Multiple annular protrusions are spaced apart along the axial direction of the fixed structure 100, forming multiple receiving grooves. During the injection molding process, the plastic layer 300 needs to fill each receiving groove sequentially, and the connection strength between the plastic layer 300 and the fixed structure 100 is enhanced through multi-segment mechanical interlocking. The spaced annular protrusions can also disperse the path of external force and reduce the risk of stress concentration.

[0048] The spaced distribution of multiple annular protrusions enables multi-point mechanical locking between the plastic layer 300 and the fixed structure 100, significantly improving the redundancy of the connection strength and enhancing the stability of the structure under complex working conditions.

[0049] In one possible implementation, the annular protrusion is wavy in shape, and the wavy protrusion undulates periodically along the outer periphery of the fixed structure 100.

[0050] A wave-shaped protrusion refers to a protruding structure 200 that undulates periodically along the outer periphery of a fixed structure 100, resembling a wave in shape. Periodic undulation means that the amplitude and interval of the protrusion's undulations repeat regularly.

[0051] The wavy protrusions undulate periodically along the outer periphery of the fixed structure 100, and the plastic layer 300 is embedded in the grooves of the wavy protrusions. This structure achieves local stress dispersion of the plastic layer 300 through the periodic undulations of the wavy protrusions, while absorbing stress caused by external vibrations or temperature changes through elastic deformation.

[0052] Furthermore, the periodic undulations of the wavy protrusions significantly enhance the stress dispersion and elastic buffering performance of the plastic layer 300, thereby further improving the connection stability and structural durability.

[0053] In an alternative embodiment, the annular protrusions are spiral-shaped, and the spiral protrusions are distributed spirally along the side of the fixing structure 100. The plastic layer 300 is embedded in the spiral grooves of the spiral protrusions. This structure achieves uniform stress distribution in the plastic layer 300 through the guiding effect of the spiral protrusions, while simultaneously dispersing external stress through the torsional characteristics of the spiral grooves.

[0054] The guiding effect and torsional properties of the spiral protrusions significantly enhance the stress homogenization ability and deformation dispersion performance of the plastic layer 300, thereby further improving the connection stability and structural durability.

[0055] In one possible implementation, the protrusion structure 200 is a square protrusion; a plurality of square protrusions are spaced apart along the circumferential direction of the fixing structure 100.

[0056] Multiple square protrusions are spaced apart, and the intermittent arrangement of the square protrusions can further save material costs while ensuring connection stability.

[0057] Furthermore, in the battery cover provided in this application embodiment, the protruding structure 200 and the fixing structure 100 are integrally formed.

[0058] An integrally molded structure refers to a structure 200 and a fixed structure 100 being formed through the same process steps, such as stamping, injection molding, or casting.

[0059] The protruding structure 200 and the fixed structure 100 are manufactured using a one-piece molding process, eliminating the need for additional welding or bonding steps. This design simplifies the manufacturing process, reduces process complexity, and ensures the bonding strength between the protruding structure 200 and the fixed structure 100.

[0060] Through the one-piece molding process, a high-strength bond between the protruding structure 200 and the fixed structure 100 is achieved, which significantly reduces manufacturing costs and process steps and improves production efficiency.

[0061] It should be noted that, as an alternative implementation, the protruding structure 200 and the fixed structure 100 can also be connected by adhesive or welding.

[0062] Furthermore, the extension length of the protruding structure 200 in the direction away from the fixed structure 100 is less than or equal to one-third of the thickness of the plastic layer 300, and greater than or equal to one-quarter of the thickness of the plastic layer 300. The extension length refers to the dimension by which the protruding structure 200 protrudes outward from the side of the fixed structure 100. The thickness of the plastic layer 300 refers to the dimension of the plastic layer 300 in the radial direction along the fixed structure 100.

[0063] The extension length of the protrusion 200 is limited to within one-third of the thickness of the plastic layer 300, and greater than or equal to one-quarter of the thickness of the plastic layer 300. This ensures that the plastic layer 300 can fully fill the receiving groove during injection molding, while avoiding stress concentration in the plastic layer 300 due to excessive length of the protrusion 200. This design balances the mechanical interlocking force with the feasibility of the injection molding process for the plastic layer 300.

[0064] Furthermore, by limiting the extension length of the protruding structure 200, a balanced connection strength between the plastic layer 300 and the fixed structure 100 is achieved, while reducing the risk of fatigue fracture of the plastic layer 300 due to stress concentration and improving structural reliability.

[0065] In this embodiment, the extension length of the protruding structure 200 is exactly one-third of the thickness of the plastic layer 300. If the extension length of the protruding structure 200 is greater than one-third of the thickness of the plastic layer 300, the connection strength of the plastic layer 300 at the protruding structure 200 will be too low, leading to breakage. If the extension length of the protruding structure 200 is less than one-quarter of the thickness of the plastic layer 300, the connection strength between the plastic layer 300 and the fixing structure 100 will be low, failing to meet the connection strength requirements between the protruding structure 200 and the plastic layer 300.

[0066] As an alternative implementation, the protruding structure 200 has a trapezoidal cross-section, and the inclined surface of the trapezoidal cross-section forms a wedge-shaped embedding effect with the plastic layer 300 during injection molding. A trapezoidal cross-section refers to the cross-section of the protruding structure 200 being trapezoidal in shape. The trapezoidal cross-section of the protruding structure 200 creates a wedge-shaped embedding effect during the injection molding of the plastic layer 300. The inclined surface design increases the contact surface area between the plastic layer 300 and the protruding structure 200, and disperses the path of external force.

[0067] By using a trapezoidal cross-section design, a uniform stress distribution is achieved between the plastic layer 300 and the fixed structure 100, significantly reducing the risk of local stress concentration and improving the stability of the connection strength.

[0068] In one possible implementation, a sealing ring 400 is also included, which is disposed between the pole post 20 and the fixing structure 100, and the sealing ring 400 is compressed by the riveting process of the fixing structure 100.

[0069] The sealing ring 400 refers to an elastic seal, such as a rubber or silicone ring, used to fill the gap between the pole post 20 and the fixed structure 100.

[0070] The sealing ring 400 is compressed during the riveting process of the fixed structure 100, filling the gap between the pole post 20 and the fixed structure 100, and achieving a sealing effect through elastic deformation. This design, in conjunction with the mechanical engagement of the protruding structure 200 and the receiving groove, further enhances the overall sealing performance.

[0071] The compression design of the sealing ring 400 achieves dynamic sealing between the terminal post 20 and the fixed structure 100, significantly improving the long-term sealing performance of the battery pack and reducing the risk of short circuits or corrosion, ultimately ensuring the electrical connection safety of the battery pack.

[0072] Furthermore, it also includes an elastic element, which is disposed within the receiving groove; the plastic layer 300 is embedded within the receiving groove through the elastic element.

[0073] Elastic materials refer to materials with resilience properties, such as silicone and thermoplastic elastomers (TPE).

[0074] The elastic material is pre-placed in the receiving groove. During the injection molding process, the plastic layer 300 deforms together with the elastic material. The elasticity of the elastic material compensates for the small deformation of the plastic layer 300, maintaining close contact between the receiving groove and the plastic layer 300.

[0075] Through dynamic compensation of elastic materials, dynamic sealing between the plastic layer 300 and the fixed structure 100 is achieved, which significantly improves the long-term sealing performance of the sealing ring 400 and reduces the risk of failure of the plastic layer 300 due to deformation.

[0076] Secondly, embodiments of this application provide a battery assembly, including a battery body and a battery cover plate disposed on the battery body according to any one of the first aspects.

[0077] Finally, it should be noted that other embodiments of this utility model will readily occur to those skilled in the art upon consideration of the specification and practice of the utility model disclosed herein. This utility model is intended to cover any variations, uses, or adaptations of this utility model that follow the general principles of this utility model and include common knowledge or customary techniques in the art not disclosed herein, and is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this utility model is limited only by the appended claims.

Claims

1. A battery cover, characterized in that, include: Cover plate body (10); A fixing structure (100) is provided on the cover plate body (10); the fixing structure (100) is used to fix the pole post (20). At least one protruding structure (200) is disposed on the side of the fixed structure (100); a receiving groove is formed between the protruding structure (200) and the cover plate body (10); A plastic layer (300) covers the outside of the fixing structure (100), and a portion of the plastic layer (300) is embedded in the receiving groove.

2. The battery cover according to claim 1, characterized in that, The protrusion structure (200) is an annular protrusion, which is disposed on the outer periphery of the fixing structure (100).

3. The battery cover according to claim 2, characterized in that, When there are multiple annular protrusions, the multiple annular protrusions are spaced apart along the axial direction of the fixed structure (100).

4. The battery cover according to claim 3, characterized in that, The annular protrusion is wavy in shape and undulates periodically along the outer periphery of the fixed structure (100).

5. The battery cover according to claim 1, characterized in that, The protrusion structure (200) is a square protrusion; a plurality of the square protrusions are spaced apart along the circumferential direction of the fixed structure (100).

6. The battery cover according to any one of claims 1-5, characterized in that, The protruding structure (200) and the fixed structure (100) are integrally formed.

7. The battery cover according to any one of claims 1-5, characterized in that, The extension length of the protruding structure (200) in the direction away from the fixed structure (100) is less than or equal to one-third of the thickness of the plastic layer (300) and greater than or equal to one-quarter of the thickness of the plastic layer (300).

8. The battery cover according to any one of claims 1-5, characterized in that, Also includes: A sealing ring (400) is disposed between the pole post (20) and the fixing structure (100), and the sealing ring (400) is compressed by the riveting process of the fixing structure (100).

9. The battery cover according to any one of claims 1-5, characterized in that, Also includes: An elastic element is disposed within the receiving groove; the plastic layer (300) is embedded within the receiving groove through the elastic element.

10. A battery assembly, characterized in that, Includes a battery body and a battery cover plate as described in any one of claims 1-9, which is disposed on the battery body.

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