A top-mount chip and its manufacturing method, and a battery cell

Abstract

This application provides a top patch, its manufacturing method, and a battery cell, relating to the field of battery technology. The top patch, used to cover the top cover of a battery cell and form insulation protection, includes: an insulating planar portion whose shape matches the shape of the top cover, and a perforated structure on the insulating planar portion. The perforated structure corresponds to a protruding structure on the top cover, and the protruding structure can pass through the perforated structure; and an insulating protrusion disposed at the perforated structure to cover the protruding structure passing through the perforated structure. Because the insulating protrusion and the insulating planar portion work together to cover and enclose the structure and shape of the top cover, good adhesion and bonding reliability between the top patch and the top cover can be ensured, thereby improving the yield rate of battery manufacturing and meeting the consistency and reliability requirements of large-scale battery production.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to a top patch and its manufacturing method, and a battery cell. Background Technology

[0002] The conventional square-shell battery cell assembly involves the interlocking of the side steps of the cell body with the steps around the bottom of the top cover, followed by laser welding for fixation. The top cover, a key component of the cell's external insulation protection, is typically manufactured using a die-cutting process and covers the surface of the cell's top cover, forming the cell's external insulation protection system together with the blue film. Existing top covers are planar structures, using insulating films such as polycarbonate (PC) as the substrate.

[0003] Existing top-mount patches can only guarantee good adhesion and bonding reliability on a flat top cover surface or when the protrusion height on the top cover surface is no higher than 1mm. They are unsuitable for top covers with protrusions greater than 1mm. When used on top covers with protrusions, they present problems such as limited material formability, poor dimensional stability and adhesion, low yield, hidden cost increases, and limited design freedom. These problems can lead to battery insulation failure or decreased sealing, overall yield loss, and increased actual costs, and make it difficult to meet the consistency and reliability requirements of large-scale mass production.

[0004] Therefore, there is an urgent need for a top-mount patch and its manufacturing method, as well as a battery cell, to avoid problems such as insulation failure or reduced sealing performance of the battery, as well as overall yield loss and increased actual cost. Summary of the Invention

[0005] This application provides a top patch and its manufacturing method, as well as a battery cell, to solve the problems of insulation failure or reduced sealing performance, as well as overall yield loss and increased actual cost in current batteries. It provides better external insulation protection for electrical properties, improves battery yield, and reduces cost losses.

[0006] In a first aspect, this application provides a top patch for covering a battery cell top cover and forming an insulating protection, comprising: an insulating planar portion, the shape of which matches the shape of the battery cell top cover, the insulating planar portion having a hollow structure, the position of which corresponds to a protruding structure on the battery cell top cover, and the protruding structure being able to pass through the hollow structure; and an insulating protrusion, the insulating protrusion being disposed at the hollow structure for covering the protruding structure passing through the hollow structure.

[0007] The above solution achieves overall insulation protection for the top cover by matching the shape of the insulating flat portion with and covering it, preventing short circuits caused by contact between the top cover and external conductive components. The perforated structure corresponds to the raised structure, allowing the raised structure to pass through, ensuring the top patch fits smoothly against the top cover surface without wrinkles or warping due to the raised structure, thus improving assembly accuracy and insulation reliability. The insulating protrusion covers the raised structure that passes through the perforated structure, achieving 360° all-around insulation coverage, preventing short circuit risks caused by exposed raised structures (such as tabs and injection holes), significantly improving the cell's safety performance. Because the insulating protrusion and insulating flat portion work together to cover and encase the structure and shape of the top cover, good adhesion and bonding reliability between the top patch and the top cover are guaranteed, thereby improving battery manufacturing yield and meeting the consistency and reliability requirements of large-scale battery production.

[0008] In one possible design, the number of insulating protrusions is multiple.

[0009] Through the above scheme, the setting of multiple insulating protrusions can independently insulate and cover multiple protrusion structures on the top cover (such as the positive and negative electrode tabs, liquid injection holes, explosion-proof valves, etc.), achieving multi-point protection and improving the redundancy and reliability of the overall insulation system. Furthermore, the multiple insulating protrusions can be designed according to the size and shape of different protrusion structures to achieve differentiated insulation protection and improve the adaptability and versatility of the top patch.

[0010] In one possible design, the insulating protrusion includes: a first protrusion corresponding to the position of the electrode tab, a second protrusion corresponding to the position of the liquid injection hole, and / or a third protrusion corresponding to the position of the explosion-proof valve.

[0011] The above scheme employs a first protrusion positioned corresponding to the tab, which precisely insulates the tab protrusion, preventing short circuits caused by contact between the tab and the outer casing or conductive components, thus ensuring the electrical safety of the battery cell. The second protrusion, positioned corresponding to the electrolyte injection hole, provides an insulated seal after electrolyte injection, preventing corrosion and short circuit risks caused by electrolyte leakage, while also avoiding exposed metal at the injection hole. The third protrusion, covering the explosion-proof valve, not only ensures the electrical safety of the battery cell but also reduces the accumulation of moisture and condensation in the explosion-proof valve area, preventing degradation of the valve's surface insulation or micro-short circuits due to condensation, thereby improving the long-term reliability of the battery cell in humid environments. The combination of the first, second, and / or third protrusions allows for flexible selection of insulation protection schemes based on the actual structural design of the battery cell's top cover, balancing comprehensive protection with cost-effectiveness. The third protrusion, together with the first and second protrusions, forms a complete three-dimensional insulation protection system for the top patch, achieving full coverage of all functional protrusion structures of the cell top cover, simplifying the assembly process, reducing the number of independent insulating components, and lowering manufacturing costs and assembly errors.

[0012] In one possible design, the height of the insulating protrusion ranges from 1mm to 8mm.

[0013] With the above solution, the height of the insulating protrusion is greater than 1mm, ensuring that the insulating protrusion can completely cover the protrusion structure and provide sufficient insulation creepage distance, effectively preventing insulation failure caused by the protrusion being too thin; sufficient protrusion height can form a stable insulation gap between the top patch and the top cover, avoiding the protrusion from being compressed and deformed under vibration or impact conditions and losing its insulation function, thus improving the safety and durability of the battery cell under complex operating conditions.

[0014] In one possible design, the insulating flat portion and the insulating protrusion are fixedly connected by a connecting layer.

[0015] The above solution uses a connecting layer to securely connect the insulating flat part and the insulating protrusion, achieving a reliable connection between the two components and preventing delamination or detachment during use, thus ensuring the integrity of the insulation structure. The connecting layer allows the insulating flat part and the insulating protrusion to be processed from different materials before assembly, taking into account both the flexibility of the flat part and the three-dimensional formability of the protrusion, thus optimizing material selection and cost control.

[0016] Secondly, this application provides a method for manufacturing a top patch, comprising the steps of: using a die-cutting process to punch an insulating film into a two-dimensional planar component that matches the shape of the insulating planar portion as described in the first aspect; using a vacuum forming process to heat the insulating film material to a preset temperature, soften the insulating film material, and then vacuum-form it into a three-dimensional component that matches the shape of the insulating protrusion portion as described in the first aspect.

[0017] The above-described solution utilizes die-cutting to process the insulating planar portion, efficiently and precisely punching out two-dimensional planar components that match the shape of the top cover. This approach offers high processing accuracy, high production efficiency, and high material utilization. The vacuum forming process is used to process the insulating protrusion. Through heating and softening followed by vacuum adsorption, the shape of the protrusion mold cavity is precisely replicated, avoiding the problems of localized thinning, whitening, or even cracking of complex three-dimensional insulating protrusions during stretching, which could lead to insulation failure or reduced sealing. Furthermore, vacuum forming ensures uniform compaction of the insulating protrusion with the protrusion structure on the top cover, preventing air bubbles and warping between the top patch and the top cover, thus improving the reliability and long-term stability of the top patch and top cover. The combination of die-cutting and vacuum forming leverages their respective advantages in two-dimensional planar processing and three-dimensional forming, enabling efficient and low-cost manufacturing of the top patch. This, in turn, improves the product yield of battery manufacturing and reduces loss costs.

[0018] In one possible design, the insulating film is made of polycarbonate (PC) film or polyethylene terephthalate (PET) film.

[0019] The above scheme uses PC film or PET film as the insulating planar material. PC film has excellent mechanical strength, heat resistance and dimensional stability, and is suitable for high-temperature conditions. PET film has good insulation properties, chemical corrosion resistance and cost advantages. Both materials are mature engineering plastics, widely available and with good processing performance. They can be flexibly selected according to the actual working environment and cost requirements of the battery cell, thereby improving the applicability and economy of the product.

[0020] In one possible design, the vacuum forming process includes: when the insulating film material is PC, the preset temperature is 145℃~155℃; when the insulating plastic sheet is PET, the preset temperature is 70℃~80℃; after the insulating film material is softened, vacuum adsorption with a vacuum degree ≥0.08MPa is used to adhere the softened insulating plastic to the cavity of the convex mold, and after cooling and shaping, it is demolded to form an insulating protrusion. The convex mold cavity includes a mold cavity with the same shape as the first protrusion at the corresponding tab position, a mold cavity with the same shape as the second protrusion at the corresponding injection hole position, and / or a mold cavity with the same shape as the third protrusion at the corresponding explosion-proof valve position.

[0021] The above scheme sets heating temperatures of 145℃~155℃ for PC and 70℃~80℃ for PET materials to ensure sufficient softening for optimal vacuum forming results, avoiding incomplete forming due to excessively low temperatures or material degradation due to excessively high temperatures. Vacuum adsorption with a vacuum degree ≥0.08MPa provides sufficient adsorption force to ensure the softened insulating plastic tightly adheres to the cavity of the convex mold, ensuring high dimensional accuracy, good surface quality, and uniform wall thickness of the formed insulating protrusions. The convex mold cavity has the same shape as the first, second, and third protrusions, ensuring that the formed insulating protrusions accurately cover the corresponding convex structures, achieving precise matching and reliable insulation.

[0022] In one possible design, before the softened insulating plastic is bonded to the cavity of the convex mold using vacuum adsorption with a vacuum degree ≥0.08MPa, a pre-stretching step is also included, in which the sheet is pre-stretched by positive pressure to 60% to 80% of the height of the insulating protrusion.

[0023] Through the above scheme, the pre-stretching step pre-stretches the sheet to 60%~80% of the height of the insulating protrusion, so that the material is pre-extended before vacuum adsorption, reducing local over-stretching and thinning during the molding process, and improving the uniformity of the wall thickness of the protrusion. Pre-stretching can effectively reduce residual stress after molding, reduce springback deformation after demolding, and improve the dimensional accuracy and shape stability of the insulating protrusion. The 60%~80% pre-stretching ratio is optimized to fully utilize the improvement effect of pre-stretching, while avoiding material cracking or molding failure due to excessive pre-stretching, thereby improving product yield and production efficiency.

[0024] Thirdly, this application provides a battery cell, comprising: a battery cell body, a top cover disposed on the top of the battery cell body, the top cover having an upwardly protruding convex structure; and a top patch as in the first aspect, the top patch covering the upper surface of the top cover.

[0025] The beneficial effects of the battery cells provided in the third aspect and the various possible designs of the third aspect can be found in the first aspect and the various possible implementations of the first aspect, and will not be repeated here.

[0026] The above description is merely an overview of the technical solutions of the embodiments of this application. In order to better understand the technical means of the embodiments of this application and to implement them in accordance with the contents of the specification, and to make the above and other objects, features and advantages of the embodiments of this application more obvious and understandable, specific implementation methods of this application are described below. Attached Figure Description

[0027] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0028] Figure 1 This is a schematic diagram of the top patch structure provided in the prior art.

[0029] Figure 2 This is a schematic diagram of the structure of the split top patch provided in one embodiment of this application.

[0030] Figure 3 This is a schematic diagram of the structure of an integrated top patch provided in another embodiment of this application.

[0031] Figure 4 This is a schematic diagram of some steps in the assembly of the split top patch onto the top cover of the battery cell according to one embodiment of this application.

[0032] Figure 5 This is a schematic diagram of another part of the steps in the step-by-step assembly of the split top patch onto the top cover of the battery cell, as provided in one embodiment of this application.

[0033] Figure 6 This is a schematic diagram of the top patch assembly on the top cover of the battery cell according to one embodiment of this application.

[0034] Figure 7 This is a schematic diagram of some steps in the assembly of the integrated top patch pre-assembled onto the top cover of the battery cell according to one embodiment of this application.

[0035] Figure 8 This is a schematic diagram of a top patch manufacturing method provided in one embodiment of this application.

[0036] Explanation of reference numerals in the attached figures: 10. Top patch of existing technology; 20. Battery cell body; 21. Convex structure; 100. Insulating flat part; 101. First cutout; 102. Second cutout; 200. Insulating protrusion; 201. Third cutout. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0038] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein in the specification of the application is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims and drawings of this application are intended to cover non-exclusive inclusion.

[0039] The term "embodiment" as used herein means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of the phrase "embodiment" in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0040] In this article, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can mean: A exists, A and B exist simultaneously, or B exists. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0041] The directional terms appearing in the following description refer to the directions shown in the figures and are not intended to limit the specific structure of this application. For example, in the description of this application, the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the figures. They are only for the convenience of describing this application 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, they should not be construed as limitations on this application.

[0042] Furthermore, the terms "first," "second," etc., in the specification and claims of this application or in the aforementioned drawings are used to distinguish different objects rather than to describe a specific order, and may explicitly or implicitly include one or more of the features.

[0043] In the description of this application, unless otherwise stated, "multiple" means two or more (including two), and similarly, "multiple groups" means two or more (including two groups).

[0044] In the description of this application, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, "connection" or "joining" in mechanical structures can refer to a physical connection, such as a fixed connection, for example, a connection fixed by a partition, such as a connection fixed by screws, bolts, or other partitions; a physical connection can also be a detachable connection, such as a snap-fit ​​or interlocking connection; a physical connection can also be an integral connection, such as a connection formed by welding, bonding, or integral molding. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0045] As can be seen from the background technology, current top patches have problems such as poor fit and low yield when facing top covers with protrusions greater than 1mm in height.

[0046] For related technologies, please refer to Figure 1 In existing technologies, the top patch 10 has a planar structure. When it is bonded to the top cover of the battery cell body 20, it is directly bonded to the upper surface of the top cover. When the top cover has a raised structure with a molding height >1mm, it can only be forcibly stretched to cover the raised structure. The stretching rate often exceeds the allowable range of the material, resulting in local thinning, whitening, or even cracking during the stretching process, leading to insulation failure or reduced sealing performance. Furthermore, the planar portion outside the raised structure will also experience uncontrollable shrinkage or wrinkling, resulting in poor flatness and dimensional stability of the planar portion. This makes it impossible for the top patch to be uniformly pressed against the surface of the top cover, resulting in problems such as air bubbles and edge lifting, which seriously affects the bonding reliability and long-term stability. Due to the significant decrease in production yield, the scrap rate increases. After considering the overall yield loss, the actual cost increases, and it is difficult to meet the consistency and reliability requirements of large-scale mass production. Furthermore, due to the limitations of the top patch structure, it also restricts the structural design and space optimization of the battery cell top cover.

[0047] In view of this, embodiments of this application provide a top patch and its manufacturing method, as well as a battery cell. The top patch includes an insulating flat portion and an insulating protrusion portion. The insulating flat portion matches the shape of the battery cell top cover and covers it, achieving overall insulation protection for the top cover and preventing short circuits caused by contact between the battery cell top cover and external conductive components. The hollow structure corresponds to the convex structure, allowing the convex structure to pass through the hollow structure, ensuring that the top patch can flatly fit the surface of the top cover without wrinkles or warping due to the presence of the convex structure, thus improving assembly accuracy and insulation reliability. The insulating protrusion portion covers the convex structure that passes through the hollow structure, achieving 360° all-round insulation coverage of the convex structure, preventing short circuit risks caused by exposed convex structures (such as tabs, injection holes, etc.), and significantly improving the safety performance of the battery cell. Because the insulating protrusions and insulating flat surfaces work together to cover and encapsulate the structure and shape of the cell top cover, good adhesion and bonding reliability between the top patch and the top cover can be guaranteed, thereby improving the yield of battery manufacturing and meeting the consistency and reliability requirements of large-scale battery production. To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings.

[0048] Figure 2 This is a schematic diagram of the structure of the split top patch provided in this embodiment. Figure 3 This is a schematic diagram of the integrated top patch provided in this embodiment. Please refer to... Figure 2 and Figure 3 This application provides a top patch for covering the top cover of a battery cell and forming an insulating protection, including: an insulating flat portion 100 and an insulating protrusion portion 200.

[0049] The insulating flat portion 100 and the insulating protrusion 200 are made of polycarbonate (PC) film or polyethylene terephthalate (PET).

[0050] You can refer to this. Figure 5 and Figure 7 The shape of the insulating plane portion 100 matches the shape of the top cover of the battery cell. The insulating plane portion 100 has a hollow structure. The position of the hollow structure corresponds to the convex structure 21 on the top cover of the battery cell, and the convex structure 21 can pass through the hollow structure.

[0051] It is understood that the insulating flat portion 100 may also include other openings, such as a first opening 101 to facilitate the passage of the pole post or a second opening 102 for reserving a gap for the explosion-proof valve. In this embodiment, the thickness of the insulating planar portion 100 ranges from 0.05 mm to 0.2 mm. A thickness of 0.05 mm to 0.2 mm facilitates processing and cost control, while still meeting insulation requirements.

[0052] An insulating protrusion 200 is provided at the hollow structure to cover the protruding structure 21 that passes through the hollow structure.

[0053] In this embodiment, the thickness of the insulating protrusion 200 is 0.1mm to 0.5mm. Insulating sheets with a thickness range of 0.1mm to 0.5mm have good thermoplasticity and sufficient mechanical strength. If the sheet is too thin, the strength after molding will be insufficient; if it is too thick, the difficulty of vacuum forming and heating will increase.

[0054] It is understandable that the thickness of the insulating protrusion 200 covering the top surface of the convex structure 21 may be different from the thickness of the outer surface of the sidewall of the convex structure 21.

[0055] In some embodiments, a third cutout 201 may be provided on the insulating protrusion 200 as needed.

[0056] In this embodiment, the thickness of the insulating flat portion 100 is less than the thickness of the insulating protrusion portion 200, so as to improve the manufacturing efficiency of the top patch and ensure the insulation reliability between the top patch and the top cover.

[0057] In this embodiment, the height of the insulating protrusion 200 ranges from 1mm to 8mm. A height greater than 1mm ensures that the insulating protrusion 200 completely covers the raised structure 21 and provides sufficient creepage distance, effectively preventing insulation failure due to excessive thinness of the protrusion. A height less than 8mm ensures the feasibility of manufacturing the insulating protrusion 200; sufficient protrusion height allows for a stable insulating gap between the top patch and the top cover, preventing the protrusion from being compressed and deformed under vibration or impact conditions, thus improving the safety and durability of the battery cell under complex operating conditions.

[0058] In this embodiment, there are multiple insulating protrusions 200.

[0059] For example, depending on the different convex structures 21 on the top cover of different structures, the insulating protrusion 200 may include: the insulating protrusion 200 includes: a first protrusion corresponding to the position of the electrode tab, a second protrusion corresponding to the position of the liquid injection hole, and / or, a third protrusion corresponding to the position of the explosion-proof valve.

[0060] The size, shape, and structure of the first, second, and third protrusions can be different.

[0061] The first protrusion corresponds to the tab's convex structure, which can precisely insulate and cover the tab convex shape to prevent short circuits caused by contact between the tab and the outer shell or conductive parts, thus ensuring the electrical safety of the battery cell. The second protrusion corresponds to the injection hole's convex structure, which can insulate and seal the injection hole convex shape after electrolyte injection, preventing corrosion and short circuit risks caused by electrolyte leakage, while also avoiding exposed metal of the injection hole. The third protrusion corresponds to the explosion-proof valve's convex structure. Covering the explosion-proof valve not only ensures the electrical safety of the battery cell, but also reduces the accumulation of moisture and condensation in the explosion-proof valve area, preventing the degradation of the explosion-proof valve's surface insulation performance or micro-short circuits caused by condensation, thus improving the long-term reliability of the battery cell in humid environments.

[0062] It is understandable that, such as Figure 4 The insulating protrusion 200 shown is the first protrusion provided by the convex bulge structure corresponding to the position of the electrode tab.

[0063] The insulating protrusion 200 may have a cutout, for example, to facilitate liquid injection or electrical connection or other practical needs.

[0064] The combination of the first, second, and / or third protrusions allows for flexible selection of insulation protection schemes based on the actual structural design of the cell top cover, balancing comprehensive protection with cost-effectiveness. The third protrusion, together with the first and second protrusions, constitutes a complete three-dimensional insulation protection system for the top patch, achieving full coverage of all functional protrusion structures 21 of the cell top cover, simplifying the assembly process, reducing the number of independent insulating components, and lowering manufacturing costs and assembly errors.

[0065] The insulating flat portion 100 and the insulating protrusion 200 are fixedly connected by a connecting layer. The connecting layer can be adhesive or a snap-fit.

[0066] For example, Figure 4 This is a schematic diagram of some steps in the assembly of the split top patch onto the top cover of the battery cell, as provided in this embodiment. Figure 5 This is a schematic diagram of another part of the steps in the step-by-step assembly of the split top patch onto the top cover of the battery cell provided in this embodiment. Figure 6 This is a schematic diagram of the top patch assembly on the top cover of the battery cell provided in this embodiment. According to... Figures 4 to 6 As shown, the installation process of the top patch is a step-by-step assembly, and the assembly steps are as follows: First, accurately position and attach the insulating protrusion 200 to the corresponding protrusion structure 21 on the top cover of the battery cell.

[0067] Then, the insulating flat part 100 is positioned and pasted onto the remaining flat area of ​​the top cover of the battery cell, and the reserved hollow structure holes on it are nested or connected with the pasted insulating protrusions 200.

[0068] After the insulating protrusion 200 is assembled, a connecting layer can be provided at the connection position with the insulating flat part 100, thereby achieving a connection between the insulating flat part 100 and the insulating protrusion 200 after the insulating flat part 100 is assembled. The connecting layer can be a double-sided adhesive layer, a hot melt adhesive layer, an ultrasonic welding layer, or a hot-pressed composite layer.

[0069] Understandably, this step-by-step assembly facilitates visual positioning and process quality control, making it particularly suitable for scenarios with complex convex structures 21 on the top cover and high positioning requirements.

[0070] Figure 7 This is a structural schematic diagram illustrating some steps in the assembly of the integrated top patch pre-assembled into the top cover of the battery cell, as provided in this embodiment. For example, according to... Figure 7 and Figure 6 As shown, the installation process of the top patch involves pre-assembly followed by final assembly. The specific steps include: In an offline workstation or using an auxiliary fixture, first align and fix the insulating protrusion 200 and the insulating flat surface 100 according to the design position, for example, Figure 6 As shown, the insulating protrusion 200 and the insulating flat part 100 can be temporarily combined by local dispensing, snapping, or pre-applying adhesive backing to form a "combined top patch assembly". Then, as Figure 7 As shown, the assembly is positioned and attached to the top cover of the battery cell as a whole in one go.

[0071] Understandably, this pre-assembly followed by assembly reduces the assembly steps on the main battery cell line, improves overall assembly efficiency, and is suitable for high-volume, fast-paced production lines.

[0072] Therefore, in different assembly methods, the insulating protrusion 200 and the insulating flat part 100 can be fixed by the connecting layer to achieve a reliable connection between the two parts, avoid delamination or detachment during use, and ensure the integrity of the insulation structure. The setting of the connecting layer allows the insulating flat part 100 and the insulating protrusion 200 to be processed separately using different materials and then assembled, taking into account the flexibility of the flat part and the three-dimensional formability of the protrusion, optimizing material selection and cost control.

[0073] This embodiment provides a method for manufacturing a top patch, used to manufacture a top patch as described in the foregoing embodiments. The structure of the top patch is as described in the foregoing embodiments, and will not be repeated in this embodiment to avoid redundancy. The manufacturing method includes: Step 1: Using a die-cutting process, the insulating film is punched into a two-dimensional planar component that matches the shape of the insulating planar portion as described in the above embodiment. The insulating planar portion is used to cover the upper surface of the battery cell top cover, and its shape matches the shape of the battery cell top cover. The insulating planar portion has a perforated structure, the position of which corresponds to the protruding structure on the battery cell top cover, and the protruding structure can pass through the perforated structure.

[0074] The insulating flat part is processed by die-cutting, which can efficiently and accurately punch out two-dimensional flat parts that match the shape of the top cover. It has high processing accuracy, high production efficiency and high material utilization.

[0075] In this embodiment, the die-cutting process is understood as the traditional adhesive die-cutting process. The die-cutting process uses a punching die to punch the insulating film in one go, with a processing accuracy of ±0.1mm, a material utilization rate of over 85%, high production efficiency, and is suitable for mass production.

[0076] Step 2: Using a vacuum forming process, the insulating film material is heated to a preset temperature to soften it. Then, it is vacuum-formed into a three-dimensional component that matches the shape of the insulating protrusion in the above embodiment.

[0077] The insulating protrusions are located at the hollowed-out structure and are used to cover the protruding structure that passes through the hollowed-out structure. The insulating protrusions are processed using a vacuum forming process, which precisely replicates the shape of the protruding mold cavity through heating and softening followed by vacuum adsorption. This avoids the problems of localized thinning, whitening, or even cracking of complex three-dimensional insulating protrusions during stretching, leading to insulation failure or decreased sealing performance. Furthermore, the vacuum forming process ensures uniform compaction between the insulating protrusions and the protruding structure on the top cover, preventing issues such as air bubbles and warping between the top patch and the top cover, thus improving the reliability and long-term stability of the top patch and top cover.

[0078] The combination of die-cutting and vacuum forming processes leverages their respective advantages in two-dimensional planar processing and three-dimensional molding, enabling efficient and low-cost manufacturing of top-mount panels, thereby improving the product yield of battery manufacturing and reducing loss costs.

[0079] In this embodiment, the insulating film is made of polycarbonate (PC) film or polyethylene terephthalate (PET) film. PC film has excellent mechanical strength, heat resistance, and dimensional stability, with a tensile strength of 60-70 MPa and a heat distortion temperature of approximately 135°C, making it suitable for top-mount applications in battery cells under high-temperature conditions. PC film also has high insulation resistivity and dielectric strength of 15 kV / mm to 20 kV / mm, effectively preventing short circuits between the battery cell top cover and external conductive components.

[0080] PET film possesses excellent insulation properties, chemical resistance, and cost advantages. The insulation resistivity of PET film is greater than 10¹. 4 With a dielectric strength of 20 kV / mm to 30 kV / mm and excellent resistance to electrolyte corrosion, PET film is approximately 30% cheaper than PC film, making it suitable for cost-sensitive applications.

[0081] Both materials are mature engineering plastics, widely available and with good processing performance. They can be flexibly selected according to the actual working environment and cost requirements of the battery cell, thereby improving the applicability and economy of the product.

[0082] In this embodiment, the vacuum forming process includes the following steps: (1) Heating and softening: Heating the insulating film material to a preset temperature to soften the sheet material.

[0083] When the insulating film material is PC, the preset temperature is 145℃~155℃. Within this temperature range, the PC sheet softens to a moderate degree, allowing it to fully stretch to fit the shape of the mold cavity without causing molecular chain degradation, yellowing, or a decrease in mechanical properties due to excessively high temperatures. If the temperature is below 145℃, the PC sheet will not soften sufficiently, making it prone to stress concentration and cracking during molding; if the temperature is above 155℃, the PC sheet may undergo thermal degradation, leading to a decrease in insulation performance.

[0084] When the insulating film material is PET, the preset temperature is 70℃~80℃. The glass transition temperature of PET is approximately 75℃. Within this temperature range, PET sheets are in a highly elastic state, exhibiting good ductility and moldability. If the temperature is below 70℃, the PET sheet becomes too hard, making molding difficult; if the temperature is above 80℃, the PET sheet may have increased crystallinity, leading to decreased transparency and increased brittleness.

[0085] (2) Vacuum adsorption molding: After the insulating film material is softened, vacuum adsorption with a vacuum degree ≥0.08MPa is used to make the softened insulating plastic fit into the cavity of the convex mold.

[0086] Vacuum adsorption with a vacuum degree ≥0.08MPa provides sufficient adsorption force to ensure that the softened insulating plastic fits tightly to every detail of the mold cavity, guaranteeing high dimensional accuracy, good surface quality, and uniform wall thickness of the molded insulating protrusion. If the vacuum degree is below 0.08MPa, there may be insufficient adhesion between the sheet and the mold cavity, resulting in defects such as wrinkles, bubbles, or uneven wall thickness on the surface of the molded insulating protrusion, affecting insulation performance and appearance quality.

[0087] (3) Cooling and shaping: After vacuum adsorption molding, the mold is cooled to cool and shape the insulating plastic in the mold cavity.

[0088] Cooling can be achieved using water cooling or air cooling. The cooling rate should be moderate; excessively rapid cooling may increase residual stress and cause warping deformation, while excessively slow cooling will reduce production efficiency. Demolding can only be performed when the sheet temperature is cooled to 20°C below its glass transition temperature.

[0089] (4) Demolding: After cooling and shaping, release the vacuum adsorption and remove the molded insulating protrusion from the mold.

[0090] When demolding, avoid excessive stretching or squeezing of the insulating protrusions to prevent deformation or damage.

[0091] The convex mold cavity includes a mold cavity with the same shape as the first protrusion at the corresponding electrode tab position, a mold cavity with the same shape as the second protrusion at the corresponding injection hole position, and / or a mold cavity with the same shape as the third protrusion at the corresponding explosion-proof valve position.

[0092] The cavity of the convex mold has the same shape as the first convex, the second convex and / or the third convex, ensuring that the insulating convex part after molding can accurately cover the convex structure at the corresponding position, so as to achieve precise matching and reliable insulation.

[0093] In some embodiments, a pre-stretching step may also be included: before the softened insulating plastic is bonded to the cavity of the convex mold using vacuum adsorption with a vacuum degree ≥0.08MPa, a pre-stretching step is also included: the sheet is pre-stretched by blowing bubbles under positive pressure to 60% to 80% of the height of the insulating protrusion.

[0094] The specific steps for the pre-stretching process are as follows: (1) Place the heated and softened insulating film material above the pre-stretching mold, and fix and seal the sheet around its perimeter with clamps.

[0095] (2) Compressed air is introduced from above the sheet, and the air pressure is controlled at 0.3 MPa ~ 0.5 MPa, so that the sheet is blown upward and expanded to form a hemispherical or nearly hemispherical bubble structure.

[0096] (3) Control the bubble height so that the highest point of the bubble structure reaches 60% to 80% of the target height of the insulating protrusion. For example, if the target height of the insulating protrusion is 5 mm, the pre-stretch bubble height is controlled at 3 mm to 4 mm.

[0097] The pre-stretching step involves blowing and stretching the sheet to 60%~80% of the height of the insulating protrusions, thus pre-extending the material before vacuum adsorption. This has the following technical effects: First, it reduces localized overstretching and thinning during the molding process. When unstretched sheets are vacuum-bonded, the material is pulled directly from a planar state into the depths of the mold cavity, resulting in a high stretch ratio and significant wall thinning near the bottom of the cavity. Pre-stretching extends the sheet by 60%–80% of its height, requiring only the remaining 20%–40% to be stretched during subsequent vacuum bonding, greatly reducing the localized stretch ratio and resulting in a more uniform wall thickness distribution.

[0098] Second, it reduces residual stress after molding. Pre-stretching causes partial plastic deformation of the material before it enters the mold cavity, reducing the amount of deformation during subsequent vacuum adsorption, thereby lowering the level of residual stress after molding. Reduced residual stress can decrease springback deformation after demolding, improving the dimensional accuracy and shape stability of the insulating protrusions.

[0099] Third, improve product yield. The 60%–80% pre-stretching ratio has been optimized and verified: if the pre-stretching ratio is below 60%, the pre-stretching effect is not significant, and the improvement in wall thickness uniformity is limited; if the pre-stretching ratio is above 80%, the sheet becomes excessively thin, making it prone to cracking or pinhole defects during subsequent vacuum adsorption. A 60%–80% pre-stretching ratio fully utilizes the improvement effect of pre-stretching while avoiding excessive pre-stretching that could lead to material cracking or molding failure, thus improving product yield and production efficiency.

[0100] It is understandable that after steps 1 and 2, the insulating protrusion and the insulating flat part can be fixedly connected.

[0101] The insulating planar portion and the insulating protrusion are fixedly connected by a connecting layer. The connecting layer allows the insulating planar portion and the insulating protrusion to be processed separately using different materials before assembly, taking into account both the flexibility of the planar portion and the three-dimensional formability of the protrusion, thus optimizing material selection and cost control.

[0102] In this embodiment, the fixed connection method may include at least one of the following: double-sided adhesive bonding, hot melt adhesive, ultrasonic welding, or hot pressing composite.

[0103] Using the above manufacturing method, the insulating protrusion of the top patch has uniform wall thickness, accurate dimensions, and smooth surface. It fits tightly with the protrusion structure of the battery cell top cover, without bubbles or curling edges, and has excellent insulation performance. The product yield can reach over 95%.

[0104] Based on the above embodiments, this embodiment also provides a battery cell, including: a battery cell body 20, a top cover, and a top patch as described in the above embodiments. The top cover is disposed on the top of the battery cell body 20 and has an upwardly protruding convex structure 21 on the top cover; the top patch covers the upper surface of the top cover.

[0105] Since the structure and beneficial effects of the top patch have been described in detail in the previous embodiments, they will not be repeated here.

[0106] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A top patch for covering the top cover of a battery cell and forming an insulating protective layer, characterized in that, include: An insulating flat portion, the shape of which matches the shape of the top cover of the battery cell, has a hollow structure on the insulating flat portion, the position of which corresponds to the protrusion structure on the top cover of the battery cell, and the protrusion structure can pass through the hollow structure; as well as An insulating protrusion is provided at the hollow structure to cover the protruding structure that passes through the hollow structure.

2. The top patch according to claim 1, characterized in that, The number of insulating protrusions is multiple.

3. The top patch according to claim 2, characterized in that, The insulating protrusion includes: a first protrusion corresponding to the position of the electrode tab, a second protrusion corresponding to the position of the injection hole, and / or a third protrusion corresponding to the position of the explosion-proof valve.

4. The top patch according to claim 1, characterized in that, The height of the insulating protrusion ranges from 1mm to 8mm.

5. The top patch according to any one of claims 1 to 4, characterized in that, The insulating flat portion and the insulating protrusion are fixedly connected by a connecting layer.

6. A method for manufacturing a top patch, characterized in that, Including the following steps: The insulating film is punched into a two-dimensional planar component that matches the shape of the insulating planar portion as described in any one of claims 1 to 5 using a die-cutting process; The insulating film material is heated to a preset temperature using a vacuum forming process, which softens the insulating film material. Then, it is vacuum-formed into a three-dimensional component that matches the shape of the insulating protrusion as described in any one of claims 1 to 5.

7. The manufacturing method according to claim 6, characterized in that, The insulating film is made of polycarbonate (PC) film or polyethylene terephthalate (PET) film.

8. The manufacturing method according to claim 7, characterized in that, The vacuum forming process includes: when the insulating film material is PC, the preset temperature is 145℃~155℃; when the insulating plastic sheet is PET, the preset temperature is 70℃~80℃. After the insulating film material is softened, vacuum adsorption with a vacuum degree ≥0.08MPa is used to adhere the softened insulating plastic to the cavity of the convex mold. After cooling and shaping, it is demolded to form the insulating protrusion. The cavity of the convex mold includes a mold cavity with the same shape as the first protrusion at the corresponding tab position, a mold cavity with the same shape as the second protrusion at the corresponding injection hole position, and / or a mold cavity with the same shape as the third protrusion at the corresponding explosion-proof valve position.

9. The manufacturing method according to claim 8, characterized in that, Before the softened insulating plastic is bonded to the cavity of the convex mold using vacuum adsorption with a vacuum degree ≥0.08MPa, a pre-stretching step is also included, in which the sheet is pre-stretched by blowing with positive pressure to 60%~80% of the height of the insulating protrusion.

10. A battery cell, characterized in that, include: Battery cell body, A top cover is disposed on the top of the battery cell body, and the top cover has an upwardly protruding convex structure; as well as The top patch as described in any one of claims 1 to 5, wherein the top patch covers the upper surface of the top cover.

Images