Cylindrical pouch cell and manufacturing method therefor

Abstract

The present application provides a cylindrical pouch cell and a manufacturing method therefor. The manufacturing method for the cylindrical pouch cell comprises: preparing a cylindrical casing (1); cutting two ends of the cylindrical casing (1) to form a plurality of sealing edges (2) sequentially arranged in a circumferential direction; stacking a positive electrode sheet, a first separator, a negative electrode sheet and a second separator and winding same to form a cell core (3); flattening tabs of a positive electrode and a negative electrode; loading the cell core (3) into the cylindrical casing (1); welding current collectors (4) to the flattened tabs; and folding the sealing edges (2), so that the folded edges cover the outer sides of the current collectors (4) and perform sealing connection. The manufacturing method for the cylindrical pouch cell of the present application can expand the application range of cylindrical pouch cells.

Description

Cylindrical pouch battery and its manufacturing method

[0001] This application claims priority to Chinese invention patent application number "202411523072.4", filed on "October 29, 2024", entitled "Cylindrical Soft Pack Battery and Method for Manufacturing the Same". Technical Field

[0002] This application relates to the field of battery technology, and more specifically, to a cylindrical pouch cell and its manufacturing method. Background Technology

[0003] Pouch batteries hold a significant position in battery technology due to their unique structure and material properties. Compared to traditional square aluminum-cased or cylindrical batteries, pouch batteries use polymers (such as aluminum-plastic film) as their outer shell, resulting in higher safety performance, lighter weight, and higher energy density. The use of aluminum-plastic film allows the battery to release energy through expansion or localized pressure relief when faced with safety risks, avoiding the possibility of explosion. Furthermore, due to their lower internal resistance, pouch batteries also have a relatively lower self-discharge rate, which is crucial for extending battery life and improving electrochemical performance. Moreover, the design flexibility of pouch batteries allows for customized shapes to meet customer needs, providing greater scope for new product development.

[0004] Existing cylindrical pouch batteries generally use a cylindrical forward punching method to form two half-shells with cylindrical recesses, and then combine the two half-shells into a cylindrical pouch outer shell. Due to the limitation of the plastic film's extensibility, it is not suitable for larger punching depths, which limits the axial length of the cylindrical pouch batteries that can be manufactured, and thus limits the application range of pouch batteries. Summary of the Invention

[0005] The main objective of this application is to provide a cylindrical soft-pack battery and a method for manufacturing the same, which can expand the application scope of cylindrical soft-pack batteries.

[0006] To achieve the above objectives, according to one aspect of this application, a method for manufacturing a cylindrical pouch cell battery is provided, comprising:

[0007] Prepare a cylindrical shell;

[0008] Multiple sealing edges are cut at both ends of the cylindrical shell to form circumferentially arranged sequentially;

[0009] The positive electrode, the first separator, the negative electrode, and the second separator are stacked and wound together to form the electrode core.

[0010] The tabs of the positive and negative electrodes are kneaded flat;

[0011] The electrode core is inserted into the cylindrical housing;

[0012] Weld the collector plate to the flattened electrode tab;

[0013] Fold the edge banding over so that it covers the outside of the manifold and forms a sealed connection.

[0014] The preparation of cylindrical shells is not limited by the ductility of materials, and cylindrical shells of any length can be made. It can meet the preparation of cylindrical shells with different axial lengths, and has a wider range of applications. This allows cylindrical pouch batteries to be used in the production of more batteries with size requirements, and better meets the production needs of cylindrical pouch batteries.

[0015] In some embodiments, the step of welding the collector plate to the flattened electrode tab includes:

[0016] The positive terminal busbar and the positive terminal collector plate are designed as an integrated unit;

[0017] The negative terminal busbar and the negative terminal collector plate are designed as an integrated unit.

[0018] Weld the flattened electrode tab to the corresponding collector plate;

[0019] The steps of folding the edge banding over the manifold and sealing it include:

[0020] The edges and manifold are smoothed and sealed with sealant.

[0021] The positive busbar is designed to be integrated with the current collector on the positive side, which allows for better contact between the positive busbar and the current collector, ensuring a larger contact area and lower contact resistance during welding, thereby saving process steps and improving the battery's conductivity.

[0022] In some embodiments, the step of welding the collector plate to the flattened electrode tab further includes:

[0023] After integrating the positive busbar with the positive collector plate, a positive post is designed on the collector plate, and a tab is inserted on the positive post. The positive post is located on the central axis of the tab, and the tab is conical with increasing cross-sectional area along the direction closer to the collector plate.

[0024] After integrating the negative busbar with the negative manifold, a negative terminal post is designed on the manifold, and an electrode tab is inserted into the negative terminal post. The negative terminal post is located on the central axis of the electrode tab, which is conical and its cross-sectional area increases along the direction closer to the manifold.

[0025] The tapered design of the tab adhesive causes its cross-sectional area to gradually increase towards the manifold. During the sealing process of the tab adhesive melting, the tab adhesive at the tip of the tapered shape will expand outwards along the outer surface of the tapered shape. As the melting process continues, the flow coverage area of ​​the tab adhesive at the tip of the tapered shape will gradually increase. Under the guidance of the outer surface of the tapered shape, it can diffuse more smoothly to the outer periphery, thereby better covering the sealing surface.

[0026] In some embodiments, the manufacturing method further includes:

[0027] An injection port is made on the negative electrode manifold;

[0028] After folding the edge banding over the manifold and sealing it, the process also includes:

[0029] Liquid is injected through the injection hole, and the opening is formed.

[0030] After the volume is divided, the injection port is sealed with UV sealant or heat-melt sealant.

[0031] It not only optimizes the internal structure of the battery and improves its performance, but also solves the technical problems of liquid injection and sealing in traditional cylindrical pouch batteries.

[0032] In some embodiments, the step of cutting multiple circumferentially arranged sealing edges at both ends of the cylindrical shell includes:

[0033] Determine the sealing edge size based on the dimensions of the flattened electrode ear;

[0034] Cut the two ends of the cylindrical shell to form trapezoidal edge banding with a preset size.

[0035] Cutting to form the sealing edge effectively releases stress on the aluminum-plastic film during the smoothing and packaging process, avoiding film wrinkles and potential leakage problems caused by stress concentration. The trapezoidal sealing edge design further enhances the stress release effect, ensuring the flatness of the aluminum-plastic film during packaging.

[0036] In some embodiments, the sealing edges at both ends of the cylindrical shell are formed by equidistant cutting.

[0037] Equidistant cutting of the sealing edge can better absorb and disperse the stress generated during core winding, avoiding wrinkles in the aluminum-plastic film during subsequent flattening and encapsulation processes, thereby improving the flatness and consistency of the encapsulation.

[0038] In some embodiments, the step of preparing the cylindrical shell includes:

[0039] The cylindrical shell is integrally molded by injection molding; or, the cylindrical shell is integrally molded by hot pressing.

[0040] The cylindrical shell, formed by injection molding or hot pressing, has good dimensional accuracy and mechanical strength, and can withstand the high pressure inside the battery, thus improving the battery's safety and reliability.

[0041] In some embodiments, the cylindrical shell is made of aluminum-plastic film, PP, PET or PE; and / or, the positive and negative electrodes of the electrode core have tabs on opposite sides.

[0042] These materials are lightweight, which helps reduce the overall weight of the battery. At the same time, the aluminum-plastic film has good encapsulation performance, which can increase the energy density of the battery while ensuring battery safety, allowing the battery to be designed into a more compact form.

[0043] According to another aspect of this application, a cylindrical pouch battery is provided, manufactured using the above-described method, comprising:

[0044] A cylindrical shell, with sealing edges at both ends, and multiple sealing edges arranged sequentially along the circumference of the cylindrical shell;

[0045] The electrode core is formed by stacking and winding a positive electrode sheet, a first diaphragm, a negative electrode sheet, and a second diaphragm. The electrode core is installed inside a cylindrical shell.

[0046] The current collector assembly is located at both ends of the electrode core and is welded to the tabs of the positive and negative electrodes. The edge is covered and sealed to the outside of the current collector assembly.

[0047] By pre-cutting to form multiple small sealing edges, the stress of the aluminum-plastic film can be dispersed during the encapsulation process, preventing stress concentration at a single point that could lead to wrinkles during encapsulation. This stress-dispersing design, especially in the flattening encapsulation process, effectively reduces encapsulation defects caused by insufficient material ductility, ensuring the consistency and stability of battery encapsulation. Since the fabrication of cylindrical casings is not limited by material ductility, casings of any length can be produced, providing greater flexibility for battery design. Battery manufacturers can design cylindrical pouch cells with different axial lengths to meet various application requirements, satisfying the market's demand for diverse battery sizes.

[0048] In some embodiments, the manifold assembly includes a manifold and a busbar, which are integral structures, and the edges of the manifold and busbar are sealed by applying sealant.

[0049] The positive busbar is designed to be integrated with the current collector on the positive side, which allows for better contact between the positive busbar and the current collector, ensuring a larger contact area and lower contact resistance during welding, thereby saving process steps and improving the battery's conductivity.

[0050] The manufacturing method of a cylindrical soft-pack battery using the technical solution of this application includes: preparing a cylindrical shell; cutting multiple sealing edges arranged sequentially along the circumference at both ends of the cylindrical shell; stacking and winding a positive electrode sheet, a first separator, a negative electrode sheet, and a second separator to form an electrode core; flattening the tabs of the positive and negative electrodes; inserting the electrode core into the cylindrical shell; welding the current collector to the flattened tabs; and folding the sealing edges so that the folded edges cover the current collector and are sealed. The manufacturing method of this cylindrical soft-pack battery directly prepares a cylindrical shell, and then places the electrode core into the cylindrical shell to prepare the cylindrical soft-pack battery. In this process, because the preparation method of the cylindrical shell does not utilize the ductility of the material to form a cylindrical structure that runs through both ends, the preparation of the cylindrical shell is not limited by the ductility of the material. It can produce cylindrical shells of any length and can meet the preparation of cylindrical shells with different axial lengths, thus having a wider range of applications. This allows the cylindrical soft-pack battery to be used in the production of more batteries with size requirements, better meeting the needs of cylindrical soft-pack battery manufacturing. In addition, because the ductility of the material is not utilized in the process of making the cylindrical shell, the prepared cylindrical shell still has maximum ductility. This feature gives the manufactured cylindrical soft-pack battery greater deformation capability during use, allowing for a larger expansion volume. Therefore, it can further increase the battery explosion threshold, making the battery less likely to cause an alarm and providing higher safety performance. Attached Figure Description

[0051] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings:

[0052] Figure 1 is a flowchart of the manufacturing method of a cylindrical soft-pack battery according to an embodiment of this application;

[0053] Figure 2 is a schematic diagram of the cylindrical shell before it is cut according to an embodiment of this application;

[0054] Figure 3 is a side view of the cylindrical shell before it is cut according to an embodiment of this application;

[0055] Figure 4 is a schematic diagram of the structure of the cylindrical shell after cutting according to an embodiment of this application;

[0056] Figure 5 is an exploded structural diagram of the cylindrical soft-pack battery before assembly according to an embodiment of this application.

[0057] Figure 6 is a schematic diagram of the current collector structure of the negative terminal of the cylindrical pouch battery according to an embodiment of this application.

[0058] The above-mentioned figures include the following reference numerals: 1. Cylindrical shell; 2. Sealing edge; 3. Electrode core; 4. Collector plate; 5. Electrode tab adhesive; 6. Positive electrode post; 7. Negative electrode post; 8. Liquid injection hole. Detailed Implementation

[0059] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0060] Referring to Figures 1 to 6, according to an embodiment of this application, the manufacturing method of a cylindrical soft-pack battery includes: preparing a cylindrical shell 1; cutting multiple sealing edges 2 arranged sequentially along the circumference at both ends of the cylindrical shell 1; stacking and winding a positive electrode sheet, a first separator, a negative electrode sheet, and a second separator to form an electrode core 3; flattening the tabs of the positive and negative electrodes; inserting the electrode core 3 into the cylindrical shell 1; welding a current collector 4 to the flattened tabs; and folding the sealing edges 2 so that the folded edges cover the current collector 4 and are sealed.

[0061] The manufacturing method of this cylindrical soft-pack battery directly prepares a cylindrical shell 1, and then places the electrode core 3 into the cylindrical shell 1 to prepare the cylindrical soft-pack battery. In this process, because the preparation method of the cylindrical shell 1 does not utilize the ductility of the material to form a cylindrical structure that runs through both ends, the preparation of the cylindrical shell 1 is not limited by the ductility of the material. It can produce cylindrical shells 1 of any length and can meet the preparation of cylindrical shells 1 with different axial lengths, thus having a wider range of applications. This allows the cylindrical soft-pack battery to be used in the production of more batteries with size requirements, better meeting the needs of cylindrical soft-pack battery manufacturing. In addition, since the ductility of the material is not utilized in the process of making the cylindrical shell 1, the prepared cylindrical shell 1 still has maximum ductility. This feature makes the manufactured cylindrical soft-pack battery have greater deformation capacity during use and can have a larger expansion volume. Therefore, it can further increase the battery explosion threshold, making the battery less likely to cause an alarm and with higher safety performance.

[0062] Furthermore, during the manufacturing process of the cylindrical shell 1, both ends of the cylindrical shell 1 were cut. This cutting allows for the pre-formation of multiple small, independent sealing edges 2 at both ends of the shell, instead of a large flat sealing edge. This design helps reduce stress concentration in the aluminum-plastic film during encapsulation, preventing wrinkles during sealing, thus reducing encapsulation stress and ensuring the stability and consistency of the battery after encapsulation. The cut sealing edges 2 form a tighter contact during heat sealing, especially during flattening encapsulation. The sealing edges fit better against the current collector, improving the heat sealing effect, preventing electrolyte leakage and the ingress of external gases, and enhancing the battery's sealing performance. The cut sealing edges result in a smoother appearance of the encapsulated battery, reducing appearance defects caused by the extensibility and uneven thickness of the aluminum-plastic film, and improving the overall aesthetics of the battery product. The design of cutting to form multiple sealing edges simplifies the encapsulation process, making subsequent flattening and encapsulation operations more convenient, reducing process steps, and improving production efficiency.

[0063] By flattening the tabs and welding them directly to the current collector, the battery assembly process is simplified, production efficiency is improved, and misalignment of the tabs inside the battery is avoided, enhancing the stability of the battery structure. This method is applicable to the production of various cylindrical pouch batteries, such as electric vehicle batteries and energy storage system batteries. Its application, especially in highly automated production lines, can significantly improve battery manufacturing quality and consistency.

[0064] In one embodiment, the cylindrical shell 1 is cylindrical and the pole core 3 is cylindrical.

[0065] In one embodiment, the positive and negative electrodes of the electrode core 3 have tabs on opposite sides.

[0066] The positive and negative electrodes of electrode core 3 are located on opposite sides, meaning that the positive electrode is located at the first end of the axial direction of electrode core 3, and the negative electrode is located at the second end of the axial direction of electrode core 3.

[0067] In one embodiment, the step of welding the manifold 4 to the flattened tab includes: integrating the positive busbar with the positive side manifold 4; integrating the negative busbar with the negative side manifold 4; welding the flattened tab to the corresponding manifold 4; and flattening and sealing the edge 2 and the busbar with sealant.

[0068] The positive busbar is designed to be integrated with the current collector 4 on the positive side. This allows for better contact between the positive busbar and the current collector 4, ensuring a larger contact area and lower contact resistance during welding, thereby saving process steps and improving the battery's conductivity.

[0069] The negative busbar is also integrated with the negative side current collector 4 to achieve the same electrical performance optimization as the positive side.

[0070] The manifold 4 is welded to the flattened electrode end face. A center hole is provided in the center of the manifold. The busbar is pre-connected to the center of the manifold 4 and is integrally formed. The tab is wrapped with adhesive.

[0071] After the tabs are flattened, they are connected to the corresponding current collector 4 using laser welding technology. Laser welding ensures the strength of the weld joint while avoiding the thermal damage that may occur with traditional welding, thus protecting the internal structure of the battery.

[0072] The edge sealing 2 and the busbar are smoothed and sealed with sealant. This step is intended to eliminate stress during the encapsulation process, prevent wrinkles from forming in the cylindrical housing 1, and ensure the sealing performance of the battery.

[0073] Through the above steps, the cylindrical pouch battery of this application optimizes the packaging process while ensuring electrical performance, thereby improving battery safety and reliability. In particular, the application of the flattening and sealing technology solves the problem of aluminum-plastic film wrinkles in traditional cylindrical pouch battery packaging, resulting in a smoother battery appearance and effective release of packaging stress, thus improving the overall quality and lifespan of the battery.

[0074] In one embodiment, the step of welding the manifold 4 to the flattened tab further includes: after integrating the positive electrode busbar with the positive electrode side manifold 4, designing a positive electrode post 6 on the manifold 4, and inserting tab adhesive 5 on the positive electrode post 6, wherein the positive electrode post 6 is located on the central axis of the tab adhesive 5, and the tab adhesive 5 is conical and its cross-sectional area increases along the direction close to the manifold 4; after integrating the negative electrode busbar with the negative electrode side manifold 4, designing a negative electrode post 7 on the manifold 4, and inserting tab adhesive 5 on the negative electrode post 7, wherein the negative electrode post 7 is located on the central axis of the tab adhesive 5, wherein the tab adhesive 5 is conical and its cross-sectional area increases along the direction close to the manifold 4.

[0075] The conical design of the tab adhesive 5 gradually increases its cross-sectional area near the current collector 4. During the sealing process of the tab adhesive 5, the tab adhesive 5 located at the tip of the cone will expand outwards along the outer surface of the cone to both ends. As the melting process progresses, the flow coverage area of ​​the tab adhesive 5 at the tip of the cone will also gradually increase. Under the guidance of the outer surface of the cone, it can diffuse more smoothly to the periphery, thereby better covering the sealing surface. This structural design makes the diffusion pattern of the tab adhesive 5 more compatible with the structural shape of the tab adhesive 5. The shape of the tab adhesive 5 is used to optimize the sealing structure of the tab adhesive 5, improve the diffusion efficiency and distribution uniformity of the tab adhesive 5, help to form a tighter seal during the heat sealing process, reduce the gas exchange between the battery and the external environment, improve the sealing performance of the battery, and thus enhance its safety and service life.

[0076] The tab adhesive 5 is inserted into the corresponding positive terminal 6 or negative terminal 7 to form a pre-installation structure. On the one hand, this allows the tab adhesive 5 to form an assembly relationship with the corresponding terminal, avoiding the loss of the tab adhesive 5. On the other hand, it makes the design structure of the tab adhesive 5 more flexible and can better match the structure of the sealing position.

[0077] Integrating the busbar and current collector 4 into a single design ensures a more stable contact between the tabs and current collector 4, reduces contact resistance, and improves the battery's electrochemical performance, such as reducing internal resistance, reducing self-discharge, and increasing energy density and cycle life.

[0078] The integrated design of the busbar and collector plate 4 reduces additional assembly steps, simplifies the battery production process, improves production efficiency, and reduces costs. Meanwhile, the tapered design of the tabs 5 and their installation on the positive and negative terminals 6 and 7 facilitates the operation of automated equipment and enables large-scale production.

[0079] By cutting both ends of the cylindrical shell 1 made of aluminum-plastic film to form sealing edges 2, and then folding and sealing it, stress can be released during the packaging process, wrinkles can be avoided at the sealing point of the cylindrical shell 1, and the flatness of the battery appearance and the overall structural stability can be improved.

[0080] In one embodiment, the current collector 4 corresponding to the positive electrode is made of aluminum, and the current collector 4 corresponding to the negative electrode is made of steel.

[0081] In one embodiment, using aluminum-plastic film as the outer casing material, and then employing the aforementioned cutting, flattening, and sealing processes, can significantly improve the safety performance of the pouch cylindrical battery and reduce the risk of explosion due to excessive internal pressure. The design of the tapered tab adhesive 5 also helps to effectively disperse stress during battery charging and discharging, preventing localized damage to the film material.

[0082] In one embodiment, the manufacturing method further includes: opening an injection hole 8 on the negative electrode busbar; after folding the sealing edge 2 to cover the outside of the collector plate 4 and sealing the connection, the method further includes: injecting liquid through the injection hole 8 to form an opening; and sealing the injection port with sealant using ultraviolet or heat-melt sealant after the volume is divided.

[0083] An injection hole 8 is provided at the negative terminal post 7, which allows for electrolyte injection and formation after cell assembly without damaging the overall battery encapsulation. After the formation process, the injection hole 8 can be sealed with UV adhesive or hot melt adhesive to ensure the stability of the electrolyte inside the battery, while also completing the venting and capacity testing after cell formation.

[0084] The design of the injection port 8 on the negative electrode busbar facilitates electrolyte injection and subsequent formation processes. Injection through the injection port 8 allows for precise control of the electrolyte volume, ensuring uniform electrolyte distribution within the battery and thus improving battery performance and safety. The sealing adhesive on the negative electrode also features an injection port for electrolyte injection and formation. After formation, sealing can be achieved using UV adhesive, hot melt adhesive, or other methods, effectively completing cell formation and venting, and sealing the cell after capacity grading.

[0085] Open-cell formation refers to the first charge-discharge process performed on a battery after electrolyte has been injected, while the battery is still in a partially sealed state. This process helps activate the active materials inside the battery and allows for the testing of various performance indicators after electrolyte injection, such as internal resistance, capacity, and voltage, to ensure battery quality.

[0086] After capacity grading, once the battery has completed its initial charge-discharge cycles and reached its designed capacity and voltage range, the electrolyte filling port is sealed using either UV sealing or hot-melt sealing with sealant. UV sealing uses UV-curing adhesive, which cures rapidly under UV light, providing excellent sealing and corrosion resistance, making it suitable for the demanding sealing environment of batteries. Hot-melt sealing uses hot-melt adhesive, which melts under heating and solidifies upon cooling to form a seal. Both sealing methods effectively prevent electrolyte leakage and the entry of outside air into the battery, ensuring its sealing performance and long-term stability, while also solving the problem of sealing the battery after electrolyte filling.

[0087] Through the above steps, the pouch cylindrical battery manufacturing method provided in this application not only optimizes the internal structure of the battery and improves its performance, but also solves the technical problems of liquid injection and sealing in traditional cylindrical pouch batteries, and has significant technical advantages and application prospects.

[0088] In one embodiment, the step of cutting multiple sealing edges 2 arranged sequentially along the circumference at both ends of the cylindrical shell 1 includes: determining the size of the sealing edge 2 according to the size of the flattened electrode tab; cutting at both ends of the cylindrical shell 1 to form trapezoidal sealing edges 2 with preset sizes.

[0089] Cutting to form the sealing edge 2 effectively releases stress on the aluminum-plastic film during the smoothing and packaging process, avoiding film wrinkles and potential leakage problems caused by stress concentration. The trapezoidal sealing edge 2 design further enhances the stress release effect, ensuring the flatness of the aluminum-plastic film during the packaging process.

[0090] The edge sealing 2 after cutting makes the appearance of the packaged battery smoother, increases the aesthetics of the product, and also facilitates the subsequent assembly of the battery, such as assembling it into a battery pack.

[0091] By precisely controlling the dimensions of the sealing edge 2, it can be ensured that after the positive and negative electrode tabs are welded to the current collector 4, the sealing performance between the cylindrical shell 1 and the current collector 4 reaches the optimal state, preventing electrolyte leakage and the intrusion of external air, thereby improving the overall sealing performance of the battery.

[0092] In one embodiment, the sealing edges 2 at both ends of the cylindrical housing 1 are formed by equidistant cuts. The equidistant cut sealing edges ensure uniform sealing at both ends of the battery, improve the sealing quality and overall performance of the battery, and are suitable for all cylindrical pouch batteries that require high sealing performance, such as batteries used in drones, power tools, etc.

[0093] The equidistantly cut sealing edge 2 can better absorb and disperse the stress generated during core winding, avoiding wrinkles in the aluminum-plastic film during subsequent flattening and encapsulation, thereby improving the flatness and consistency of the encapsulation. When folded and sealed, the cut sealing edge 2 can fit more tightly against the edge of the current collector 4, forming a more uniform and tighter sealing ring, reducing the risk of electrolyte leakage and enhancing the battery's sealing performance. The equidistant cut of the sealing edge 2 helps maintain the stability of the casing structure, ensuring that the cylindrical structure of the battery is not easily deformed even during flattening, thus ensuring the battery's dimensional accuracy and mechanical properties.

[0094] In one embodiment, the step of preparing the cylindrical shell 1 includes: integrally molding the cylindrical shell 1 by injection molding; or integrally molding the cylindrical shell 1 by hot pressing.

[0095] Injection molding offers high dimensional accuracy and surface finish, making it suitable for producing housings of fixed length and diameter, thus helping to ensure battery consistency. It is well-suited for mass production, enabling the rapid and continuous manufacture of large quantities of housings, reducing production costs. The injection molding process can easily accommodate complex shapes and structures, such as pre-installed edge sealing or center holes on the housing.

[0096] Hot pressing allows materials to stretch to a certain extent under temperature and pressure. For materials like aluminum-plastic films, it better accommodates the need for flattening and encapsulation, reducing material stress and wrinkling. Hot pressing provides tighter material contact, helping to improve sealing and reduce the risk of electrolyte leakage. Hot pressing is suitable for a variety of materials, including aluminum-plastic films, PP, PE, and PET, meeting the needs of different battery designs.

[0097] The cylindrical shell 1, formed by injection molding or hot pressing, has good dimensional accuracy and mechanical strength, can withstand the high pressure inside the battery, and improves the safety and reliability of the battery.

[0098] In one embodiment, the cylindrical shell 1 can also be formed by rolling the rectangular film or rectangular plate into a cylindrical shape and then hot-pressing it at the joint position, based on the processing of the rectangular film or rectangular plate.

[0099] In one embodiment, the cylindrical shell 1 is made of aluminum-plastic film, PP, PET, or PE.

[0100] The cylindrical shell 1, made of materials such as aluminum-plastic film, PP (polypropylene), PET (polyethylene terephthalate), or PE (polyethylene), can achieve the following effects:

[0101] These materials are lightweight, which helps reduce the overall weight of the battery. At the same time, the aluminum-plastic film has good encapsulation performance, which can increase the energy density of the battery while ensuring battery safety, allowing the battery to be designed into a more compact form.

[0102] Aluminum-plastic film and polymer materials have good ductility and toughness. When the internal pressure of the battery increases, these materials can expand rather than rupture. Compared with metal casings, pouch batteries are less likely to explode in the event of danger, thus improving safety performance.

[0103] Polymer materials such as PP, PET, and PE have excellent flexibility and adaptability, which can accommodate the volume changes of the battery during charging and discharging, reducing the damage to the casing caused by changes in the internal pressure of the battery.

[0104] These materials are relatively inexpensive and can reduce complex processes such as denting during manufacturing, simplifying the production process and reducing production costs.

[0105] Polymer materials are more environmentally friendly than metal casings in terms of waste disposal, reducing the difficulty of battery recycling and processing.

[0106] Due to the properties of the materials, pouch batteries can be designed in more flexible shapes, and can be designed into different shapes according to specific application requirements, such as the cylindrical shape in this application, to adapt to different device and space requirements.

[0107] Referring to Figures 2 to 6, according to the embodiments of this application, the cylindrical soft-pack battery is manufactured using the above-described manufacturing method, comprising: a cylindrical shell 1, with sealing edges 2 respectively provided at both ends of the cylindrical shell 1, and multiple sealing edges 2 arranged sequentially along the circumference of the cylindrical shell 1; an electrode core 3, formed by stacking and winding a positive electrode sheet, a first separator, a negative electrode sheet, and a second separator, and the electrode core 3 is installed inside the cylindrical shell 1; and a current collector assembly, disposed at both ends of the electrode core 3 and welded to the tabs of the positive and negative electrodes, with the sealing edges 2 covering the outside of the current collector assembly and sealingly connected to the current collector assembly.

[0108] By pre-cutting to form multiple small sealing edges, the stress on the aluminum-plastic film can be dispersed during the encapsulation process, preventing stress concentration at a single point that could lead to wrinkles during encapsulation. This stress-dispersing design, especially in the flattening encapsulation process, effectively reduces encapsulation defects caused by insufficient material ductility, ensuring the consistency and stability of battery encapsulation.

[0109] The multiple sealing edges 2, after being cut, can form a tighter contact with the current collector assembly during heat sealing, improving the sealing effect during the flattening and encapsulation process. This design ensures that the electrolyte will not leak from the encapsulation edges, while also preventing external gases from entering the battery, enhancing the overall sealing of the battery and significantly improving its long-term stability and safety performance.

[0110] Edge sealing and cutting helps the battery to have a smoother appearance after packaging, reducing appearance defects such as bubbles and dents that may be caused by the extensibility and uneven thickness of the aluminum-plastic film, thus improving the aesthetics and overall texture of the battery product.

[0111] The design of multiple sealing edges simplifies the packaging process, reduces process steps, and makes the subsequent flattening and packaging process more convenient and efficient, thereby reducing production costs and improving production efficiency.

[0112] Since the fabrication of the cylindrical casing 1 is not limited by the material's ductility, casings of any length can be produced, providing greater flexibility for battery design. Battery manufacturers can design cylindrical pouch cells with different axial lengths according to different application requirements, meeting the market's demand for diverse battery sizes.

[0113] The cylindrical shell 1 maintains maximum ductility during the manufacturing process, which allows the cylindrical pouch battery to withstand greater deformation during use without breaking, improving the battery's ability to expand its volume, thereby increasing the battery's explosion threshold and enhancing its safety performance.

[0114] In summary, by setting multiple circumferentially arranged sealing edges 2 at both ends of the cylindrical shell 1, and carefully designing and matching them with the positive and negative electrode tabs of the electrode core 3 and the current collector assembly, not only can the technical difficulties in the packaging process be effectively solved, but the performance of the battery can also be significantly improved, including enhanced sealing, improved appearance, improved safety performance and increased design flexibility.

[0115] In one embodiment, the tabs of the positive and negative electrodes of the electrode core 3 are disposed on different sides of the electrode core 3.

[0116] In one embodiment, the manifold assembly includes a manifold 4 and a busbar, the manifold 4 and the busbar being an integral structure, and the edge sealing 2 and the busbar being smoothed and sealed with sealant.

[0117] The positive busbar is designed to be integrated with the current collector 4 on the positive side. This allows for better contact between the positive busbar and the current collector 4, ensuring a larger contact area and lower contact resistance during welding, thereby saving process steps and improving the battery's conductivity.

[0118] The negative busbar is also integrated with the negative side current collector 4 to achieve the same electrical performance optimization as the positive side.

[0119] After the tabs are flattened, they are connected to the corresponding current collector 4 using laser welding technology. Laser welding ensures the strength of the weld joint while avoiding the thermal damage that may occur with traditional welding, thus protecting the internal structure of the battery.

[0120] The edge sealing 2 and the busbar are smoothed and sealed with sealant. This step is intended to eliminate stress during the encapsulation process, prevent wrinkles from forming in the cylindrical housing 1, and ensure the sealing performance of the battery.

[0121] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0122] It should be noted that the terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in sequences other than those illustrated or described herein.

[0123] The above descriptions are merely some embodiments of this application and are not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for manufacturing a cylindrical soft-pack battery, characterized in that, include: Prepare a cylindrical shell (1); Multiple sealing edges (2) are cut at both ends of the cylindrical shell (1) to form a series of circumferentially arranged edges; The positive electrode, the first separator, the negative electrode and the second separator are stacked and wound to form the electrode core (3); The tabs of the positive and negative electrodes are kneaded flat; The pole core (3) is inserted into the cylindrical shell (1); Weld the collector plate (4) to the flattened electrode lug; Fold the edge seal (2) over so that the folded edge covers the outside of the manifold (4) and is sealed.

2. The method for manufacturing a cylindrical soft-pack battery according to claim 1, characterized in that, The steps for welding the collector plate (4) to the flattened electrode lug include: The positive terminal busbar and the positive terminal collector plate (4) are designed as an integrated unit; The negative terminal busbar and the negative terminal collector plate (4) are designed as an integrated unit; Weld the flattened electrode tab to the corresponding collector plate (4); The steps of folding the edge seal (2) over the outside of the manifold (4) and sealing it include: The edge banding (2) and the manifold are smoothed and sealed with sealant.

3. The method for manufacturing a cylindrical soft-pack battery according to claim 2, characterized in that, The steps of welding the collector plate (4) to the flattened electrode lug also include: After integrating the positive terminal busbar with the positive terminal collector plate (4), a positive terminal post (6) is designed on the collector plate (4), and a tab adhesive (5) is inserted on the positive terminal post (6). The positive terminal post (6) is located on the central axis of the tab adhesive (5), wherein the tab adhesive (5) is conical and the cross-sectional area increases along the direction close to the collector plate (4). After integrating the negative electrode busbar with the negative electrode side collector plate (4) into a single design, a negative electrode post (7) is designed on the collector plate (4), and an electrode tab (5) is inserted on the negative electrode post (7). The negative electrode post (7) is located on the central axis of the electrode tab (5), wherein the electrode tab (5) is conical and its cross-sectional area increases along the direction close to the collector plate (4).

4. The method for manufacturing a cylindrical soft-pack battery according to claim 2, characterized in that, The production method also includes: An injection hole (8) is made on the busbar of the negative electrode; After folding the edge seal (2) to cover the outside of the manifold (4) and sealing the connection, the process further includes: Liquid is injected through the injection hole (8), and the opening is formed; After the volume is divided, the injection port is sealed with UV sealant or heat-melt sealant.

5. The method for manufacturing a cylindrical soft-pack battery according to claim 1, characterized in that, The steps of cutting multiple circumferentially arranged edge seals (2) at both ends of the cylindrical shell (1) include: Determine the sealing edge (2) size based on the size of the flattened electrode ear; Cut the two ends of the cylindrical shell (1) to form trapezoidal sealing edges (2) with a preset size.

6. The method for manufacturing a cylindrical soft-pack battery according to claim 5, characterized in that, The sealing edges (2) at both ends of the cylindrical shell (1) are formed by equidistant cutting.

7. The method for manufacturing a cylindrical soft-pack battery according to claim 1, characterized in that, The steps for preparing the cylindrical shell (1) include: The cylindrical shell is integrally molded using injection molding (1); or A cylindrical shell is integrally formed by hot pressing (1).

8. The method for manufacturing a cylindrical soft-pack battery according to claim 1, characterized in that, The cylindrical shell (1) is made of aluminum-plastic film, PP, PET or PE, and / or the positive and negative electrodes of the core (3) are on opposite sides of the outlet tab.

9. A cylindrical soft-pack battery, manufactured using the method described in any one of claims 1 to 8, characterized in that, include: A cylindrical shell (1) is provided with sealing edges (2) at both ends of the cylindrical shell (1), and multiple sealing edges (2) are arranged sequentially along the circumference of the cylindrical shell (1); The electrode core (3) is formed by stacking and winding a positive electrode sheet, a first diaphragm, a negative electrode sheet, and a second diaphragm. The electrode core (3) is installed inside the cylindrical shell (1). The collector plate assembly is disposed at both ends of the electrode core (3) and welded to the tabs of the positive electrode and the negative electrode. The sealing edge (2) covers the outside of the collector plate assembly and is sealed to the collector plate assembly.

10. The cylindrical soft-pack battery according to claim 9, characterized in that, The manifold assembly includes a manifold (4) and a busbar. The manifold (4) and the busbar are an integral structure. The edge sealing (2) and the busbar are flattened and sealed with sealant.

Images