Cylindrical soft package battery and manufacturing method thereof

Abstract

The invention provides a cylindrical soft package battery and a manufacturing method thereof. The manufacturing method of the cylindrical soft package battery comprises the following steps: preparing the cylindrical shell (1); the two ends of the cylindrical shell (1) are cut to form a plurality of sealing edges (2) which are sequentially arranged in the circumferential direction; the positive plate, the first diaphragm, the negative plate and the second diaphragm are stacked and wound to form a pole core (3), and tabs are arranged on different sides of a positive electrode and a negative electrode of the pole core (3); the tabs of the positive electrode and the negative electrode are rubbed to be flat; the pole core (3) is arranged in the cylindrical shell (1); the collector plate (4) is welded with the flattened tabs; and the sealing edge (2) is turned over, so that the turnup wraps the collector plate (4) and is in sealing connection with the collector plate (4). According to the manufacturing method of the cylindrical soft package battery, the application range of the cylindrical soft package battery can be expanded.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and in particular to a cylindrical soft-pack battery and a manufacturing method thereof. Background Art

[0002] Soft-pack batteries occupy an important position in the field of battery technology due to their unique structure and material properties. Compared with traditional square aluminum shell batteries or cylindrical batteries, soft-pack batteries use polymers (such as aluminum-plastic film) as the outer shell, which has higher safety performance, lighter weight and higher energy density. The use of aluminum-plastic film enables the battery to release energy by expansion or local pressure relief when facing safety risks, avoiding the possibility of explosion. In addition, due to the low internal resistance of soft-pack batteries, their self-discharge rate is also relatively small, which is crucial to extending battery life and improving electrochemical performance. Furthermore, the design flexibility of soft-pack batteries enables them to be customized according to customer needs, providing a broader space for new product development.

[0003] Existing cylindrical soft-pack batteries generally use cylindrical forward punching to form two half shells with cylindrical pits, and then combine the two half shells into a cylindrical soft-pack outer shell. Due to the limitation of the ductility of the plastic film, it is not suitable for a larger punching depth. Therefore, the axial length of the cylindrical soft-pack battery that can be produced is limited, which in turn limits the scope of application of the soft-pack battery. Summary of the invention

[0004] The main purpose of the present invention is to provide a cylindrical soft-pack battery and a manufacturing method thereof, which can expand the application scope of the cylindrical soft-pack battery.

[0005] In order to achieve the above object, according to one aspect of the present invention, a method for manufacturing a cylindrical soft-pack battery is provided, comprising:

[0006] preparing a cylindrical shell;

[0007] Cutting at both ends of the cylindrical shell to form a plurality of edge seals arranged in sequence along the circumferential direction;

[0008] The positive electrode sheet, the first separator, the negative electrode sheet and the second separator are stacked and wound to form a pole core, and the positive electrode and the negative electrode of the pole core have pole ears on opposite sides;

[0009] Flatten the positive and negative pole ears;

[0010] Install the pole core into the cylindrical shell;

[0011] Weld the collector plate to the flattened pole ear;

[0012] The sealing edge is folded so that the flange is wrapped around the collecting plate and sealed.

[0013] The preparation of cylindrical shells is not limited by the ductility of the material, and cylindrical shells of any length can be produced. It can meet the preparation of cylindrical shells of different axial lengths and has a wider range of applications. This allows cylindrical soft-pack batteries to be used in the production of more batteries with size requirements, better meeting the production needs of cylindrical soft-pack batteries.

[0014] Furthermore, the step of welding the collector plate and the flattened pole ear includes:

[0015] The busbar of the positive electrode and the current collector on the positive electrode side are designed to be integrated;

[0016] The negative electrode busbar and the current collector on the negative electrode side are designed to be integrated;

[0017] Welding the flattened pole ear to the corresponding current collecting plate;

[0018] The steps of folding the sealing edge so that the flange is wrapped around the collector plate and sealed and connected include:

[0019] The edge banding and busbar are smoothed and sealed by using sealant.

[0020] The positive bus is pre-designed as one with the current collector on the positive side, which can ensure better contact between the positive bus and the current collector, ensure a larger contact area and lower contact impedance during welding, thereby saving process flow and improving the conductivity of the battery.

[0021] Furthermore, the step of welding the collector plate and the flattened pole ear further includes:

[0022] After the busbar of the positive electrode is integrated with the current collector on the positive electrode side, a positive electrode column is designed on the current collector, and a pole ear glue is passed through the positive electrode column. The positive electrode column is located on the central axis of the pole ear glue, wherein the pole ear glue is conical, and the cross-sectional area increases gradually along the direction close to the current collector;

[0023] After the negative electrode bus and the current collecting plate on the negative electrode side are integrated into an integrated design, a negative electrode column is designed on the current collecting plate, and a pole ear glue is passed through the negative electrode column. The negative electrode column is located on the central axis of the pole ear glue, wherein the pole ear glue is conical, and the cross-sectional area increases gradually along the direction approaching the current collecting plate.

[0024] The conical design of the ear glue causes its cross-sectional area to gradually increase in the direction close to the collecting plate. During the process of melting the ear glue for sealing, the ear glue at the tip of the cone will flow outward along the outer surface of the cone toward both ends during the melting process. As the melting process proceeds, the flow coverage area of ​​the ear glue at the tip of the cone will gradually increase. Under the guidance of the outer surface of the cone, it can diffuse toward the periphery more smoothly, thereby better covering the sealing surface.

[0025] Furthermore, the preparation method also includes:

[0026] A liquid injection hole is provided on the bus bar of the negative electrode;

[0027] After the step of folding the sealing edge so that the flange is wrapped around the collector plate and sealed, the step further includes:

[0028] Liquid is injected through the injection hole to form an opening;

[0029] After the volume separation is completed, the liquid injection port is UV-sealed or hot-melt-sealed using sealant.

[0030] It not only optimizes the internal structure of the battery and improves the battery performance, but also solves the technical difficulties of traditional cylindrical soft-pack batteries in liquid filling and sealing.

[0031] Furthermore, the step of cutting at both ends of the cylindrical shell to form a plurality of edge seals arranged in sequence along the circumferential direction includes:

[0032] Determine the edge sealing size according to the size of the flattened pole ear;

[0033] Cutting is performed at both ends of the cylindrical shell to form a trapezoidal edge seal with a preset size.

[0034] Cutting to form edge sealing can effectively release the stress of the aluminum-plastic film during the flattening and packaging process, avoiding film wrinkles and possible leakage caused by stress concentration. The trapezoidal edge sealing design further enhances the effect of stress release and ensures the flatness of the aluminum-plastic film during the packaging process.

[0035] Furthermore, the edge sealing at both ends of the cylindrical shell is formed by equidistant cutting.

[0036] The equidistantly cut edge banding can better absorb and disperse the stress generated during the winding of the pole core, avoiding wrinkles in the aluminum-plastic film during the subsequent flattening and packaging process, thereby improving the flatness and consistency of the packaging.

[0037] Furthermore, the step of preparing the cylindrical shell includes:

[0038] The cylindrical shell is integrally formed by injection molding; or, the cylindrical shell is integrally formed by hot pressing.

[0039] The cylindrical shell 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.

[0040] Furthermore, the material of the cylindrical shell is aluminum-plastic film, PP, PET or PE.

[0041] These materials are light, which helps to reduce the overall weight of the battery. At the same time, the aluminum-plastic film has good packaging properties, which can increase the energy density of the battery while ensuring battery safety, allowing the battery to be designed in a more compact form.

[0042] According to another aspect of the present invention, there is provided a cylindrical soft-pack battery, which is manufactured using the above-mentioned manufacturing method, comprising:

[0043] A cylindrical shell, with sealed edges respectively disposed at both ends of the cylindrical shell, and a plurality of sealed edges are sequentially disposed along the circumference of the cylindrical shell;

[0044] The pole core is formed by stacking and winding a positive electrode sheet, a first separator, a negative electrode sheet and a second separator, wherein the positive and negative electrode ears of the pole core are arranged on different sides of the pole core, and the pole core is installed in a cylindrical shell;

[0045] The current collecting plate assembly is arranged at the positive terminal and the negative terminal of the pole core and is welded to the positive and negative pole ears. The sealing edge is coated on the outside of the current collecting plate assembly and is sealed and connected to the current collecting plate assembly.

[0046] By pre-cutting to form multiple small edge seals, the stress of the aluminum-plastic film can be dispersed during the packaging process to avoid stress concentration at a certain point causing wrinkles during packaging. This design of dispersing stress, especially in the flattening packaging process, can effectively reduce packaging defects caused by insufficient material ductility, ensuring the consistency and stability of battery packaging. Since the preparation of the cylindrical shell is not limited by the ductility of the material, shells of any length can be made, which provides greater flexibility in battery design. Battery manufacturers can design cylindrical soft-pack batteries of different axial lengths according to different application requirements, meeting the market demand for battery size diversity.

[0047] Furthermore, the collecting plate assembly includes a collecting plate and a bus bar, the collecting plate and the bus bar are an integrated structure, and the edge seal and the bus bar are flattened and sealed by a sealant.

[0048] The positive bus is pre-designed as one with the current collector on the positive side, which can ensure better contact between the positive bus and the current collector, ensure a larger contact area and lower contact impedance during welding, thereby saving process flow and improving the conductivity of the battery.

[0049] By applying the technical solution of the present invention, the manufacturing method of a cylindrical soft-pack battery includes: preparing a cylindrical shell; cutting at both ends of the cylindrical shell to form a plurality of sealed edges arranged in sequence along the circumferential direction; stacking and winding the positive electrode sheet, the first diaphragm, the negative electrode sheet and the second diaphragm to form a pole core, with the positive and negative poles of the pole core having pole ears on opposite sides; flattening the pole ears of the positive and negative poles; placing the pole core into the cylindrical shell; welding the current collecting plate to the flattened pole ears; folding the sealed edges so that the flanges are covered on the outside of the current collecting plate and sealed and connected. The manufacturing method of the cylindrical soft-pack battery directly prepares a cylindrical shell, and then places the pole core into the cylindrical shell to prepare the cylindrical soft-pack battery. In this process, since the preparation method of the cylindrical shell does not use the ductility of the material to achieve the preparation of the cylindrical shell in the process of forming a cylindrical structure with two ends penetrating, the preparation of the cylindrical shell is not limited by the ductility of the material, and a cylindrical shell of any length can be manufactured, which can meet the preparation of cylindrical shells of different axial lengths and has a wider range of applications, so that the cylindrical soft-pack battery can be applied to the production of more batteries with requirements on size, and better meet the production needs of cylindrical soft-pack batteries. In addition, since the ductility of the material is not used in the process of manufacturing the cylindrical shell, the prepared cylindrical shell still has the greatest ductility. This feature enables the manufactured cylindrical soft-pack battery to have a greater deformation ability during use and a larger expansion volume, so that the threshold of the battery explosion can be further increased, making the battery less likely to explode and having higher safety performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0051] Figure 1 is a flow chart of a method for manufacturing a cylindrical soft-pack battery according to an embodiment of the present invention;

[0052] Figure 2 is a schematic structural diagram of a cylindrical shell of an embodiment of the present invention before cutting;

[0053] Figure 3 is a schematic side view of the structure of the cylindrical shell of an embodiment of the present invention before cutting;

[0054] Figure 4 is a schematic structural diagram of a cylindrical shell after cutting according to an embodiment of the present invention;

[0055] Figure 5 is a schematic diagram of the exploded structure of a cylindrical soft-pack battery according to an embodiment of the present invention before assembly;

[0056] Figure 6It is a schematic diagram of the structure of the current collecting plate at the negative terminal of the cylindrical soft-pack battery according to an embodiment of the present invention.

[0057] The above drawings include the following reference numerals:

[0058] 1. Cylindrical shell; 2. Edge sealing; 3. Pole core; 4. Collector plate; 5. Pole ear glue; 6. Positive pole; 7. Negative pole; 8. Liquid injection hole. DETAILED DESCRIPTION

[0059] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0060] See also Figures 1 to 6 As shown, according to an embodiment of the present invention, a method for manufacturing a cylindrical soft-pack battery includes: preparing a cylindrical shell 1; cutting at both ends of the cylindrical shell 1 to form a plurality of edge seals 2 arranged in sequence along the circumferential direction; stacking and winding the positive electrode sheet, the first diaphragm, the negative electrode sheet and the second diaphragm to form a pole core 3, with the positive and negative poles of the pole core 3 having pole ears on opposite sides; flattening the pole ears of the positive and negative poles; inserting the pole core 3 into the cylindrical shell 1; welding the current collecting plate 4 to the flattened pole ears; folding the edge seal 2 so that the flange is covered on the outside of the current collecting plate 4 and sealed and connected.

[0061] The manufacturing method of the cylindrical soft-pack battery directly prepares the cylindrical shell 1, and then places the pole core 3 into the cylindrical shell 1 to prepare the cylindrical soft-pack battery. In this process, since the preparation method of the cylindrical shell 1 does not use the ductility of the material to achieve the preparation of the cylindrical shell 1 in the process of forming a cylindrical structure with two ends penetrating, the preparation of the cylindrical shell 1 is not limited by the ductility of the material, and the cylindrical shell 1 of any length can be manufactured, which can meet the preparation of cylindrical shells 1 with different axial lengths, and has a larger scope of application, so that the cylindrical soft-pack battery can be applied to the production of more batteries with requirements on size, and better meet the production needs of cylindrical soft-pack batteries. In addition, since the ductility of the material is not used in the process of manufacturing the cylindrical shell 1, the prepared cylindrical shell 1 still has the greatest ductility. This feature enables the manufactured cylindrical soft-pack battery to have a greater deformation ability during use and can have a larger expansion volume, so that the threshold of the battery explosion can be further increased, making the battery less likely to explode and having higher safety performance.

[0062] In addition, during the production process of the cylindrical shell 1, the two ends of the cylindrical shell 1 are cut. Through cutting, multiple small independent edge seals 2 can be formed at both ends of the shell in advance, rather than a large plane edge seal. Such a design helps to reduce the stress concentration of the aluminum-plastic film during the packaging process, avoid wrinkles during sealing, thereby reducing the packaging stress and ensuring the stability and consistency of the battery after packaging. The edge seal 2 after cutting can form a closer contact during the heat sealing process, especially when flattening the package, the edge seal can be better fitted outside the collector plate, improve the sealing effect of the heat seal, prevent electrolyte leakage and external gas from entering, and enhance the sealing performance of the battery. The edge seal after cutting can make the appearance of the packaged battery smoother, reduce the appearance defects caused by the ductility and uneven thickness of the aluminum-plastic film, and improve the overall aesthetics of the battery product. The design of cutting to form multiple edge seals can simplify the packaging process, making the operation more convenient in the later flattening and packaging process, reducing the process steps and improving production efficiency.

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

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

[0065] The positive and negative poles of the pole core 3 have pole tabs on different sides, which means that the positive pole tab is located at a first axial end of the pole core 3 , and the negative pole tab is located at a second axial end of the pole core 3 .

[0066] In one embodiment, the step of welding the current collecting plate 4 to the flattened pole ear includes: integrating the bus bar of the positive electrode with the current collecting plate 4 on the positive electrode side; integrating the bus bar of the negative electrode with the current collecting plate 4 on the negative electrode side; welding the flattened pole ear to the corresponding current collecting plate 4; flattening and sealing the edge sealing 2 and the bus bar with a sealant.

[0067] The positive bus is pre-designed as one with the current collecting plate 4 on the positive side, so that the positive bus and the current collecting plate 4 have better contact, ensuring a larger contact area and lower contact impedance during welding, thereby saving process flow and improving the conductivity of the battery.

[0068] The negative electrode busbar is also designed to be integrated with the current collecting plate 4 on the negative electrode side to achieve the same electrical performance optimization as the positive electrode side.

[0069] The current collecting plate 4 is welded to the flattened electrode end surface, a center hole is provided at the center of the current collecting plate, the bus is pre-connected to the center of the current collecting plate 4, an integrally formed connection is made, and the pole ear glue is wrapped on the bus.

[0070] After the tabs are flattened, the tabs are connected to the corresponding current collecting plates 4 by laser welding technology. Laser welding can ensure the strength of the welding points while avoiding the thermal damage that may be caused by traditional welding, thereby protecting the internal structure of the battery.

[0071] The edge seal 2 and the bus bar are flattened and sealed by using a sealant. This step is intended to eliminate stress during the packaging process, avoid wrinkles in the cylindrical shell 1, and ensure the sealing performance of the battery.

[0072] Through the above steps, the cylindrical soft-pack battery of the present invention optimizes the packaging process while ensuring electrical performance, thereby improving the safety and reliability of the battery. In particular, the application of the flattening sealing technology solves the wrinkle problem of the aluminum-plastic film in the traditional cylindrical soft-pack battery packaging, making the battery appearance smoother, and effectively releasing the packaging stress, thereby improving the overall quality and life of the battery.

[0073] In one embodiment, the step of welding the current collecting plate 4 to the flattened pole ear also includes: after the positive electrode bus is integrated with the current collecting plate 4 on the positive electrode side, a positive electrode column 6 is designed on the current collecting plate 4, and a pole ear glue 5 is passed through the positive electrode column 6, and the positive electrode column 6 is located on the central axis of the pole ear glue 5, wherein the pole ear glue 5 is conical, and the cross-sectional area increases along the direction approaching the current collecting plate 4; after the negative electrode bus is integrated with the current collecting plate 4 on the negative electrode side, a negative electrode column 7 is designed on the current collecting plate 4, and a pole ear glue 5 is passed through the negative electrode column 7, and the negative electrode column 7 is located on the central axis of the pole ear glue 5, wherein the pole ear glue 5 is conical, and the cross-sectional area increases along the direction approaching the current collecting plate 4.

[0074] The conical design of the ear glue 5 causes its cross-sectional area to gradually increase in the direction close to the collecting plate 4. In the process of melting the ear glue 5 for sealing, the ear glue 5 at the tip of the cone will flow outward along the outer surface of the cone during the melting process. As the melting process proceeds, the flow coverage area of ​​the ear glue 5 at the tip of the cone will gradually increase. Under the guidance of the conical outer surface, it can diffuse more smoothly to the periphery, thereby better covering the sealing surface. This structural design makes the diffusion form of the ear glue 5 more compatible with the structural form of the ear glue 5, and utilizes the shape of the ear glue 5 to optimize the sealing structure of the ear glue 5, thereby improving the diffusion efficiency and distribution uniformity of the ear glue 5, and helping to form a tighter seal during the heat sealing process, reduce the gas exchange between the inside of the battery and the external environment, and improve the sealing performance of the battery, thereby enhancing its safety and service life.

[0075] The ear glue 5 is passed through the corresponding positive electrode column 6 or negative electrode column 7 to form a pre-installed structure. On the one hand, it can form an assembly relationship between the ear glue 5 and the corresponding electrode to avoid the loss of the ear glue 5. On the other hand, it can make the design structure of the ear glue 5 more flexible and more compatible with the structure of the sealing position.

[0076] Integrating the busbar and the collector plate 4 can ensure more stable contact between the pole ear and the collector plate 4, reduce contact resistance, and improve the electrochemical performance of the battery, such as reducing the internal resistance of the battery, reducing self-discharge, and improving the energy density and cycle life of the battery.

[0077] The integrated design of the busbar and the collector plate 4 can also reduce additional assembly steps, simplify the battery production process, improve production efficiency and reduce costs. At the same time, the conical design of the ear glue 5 and its installation on the positive electrode column 6 and the negative electrode column 7 also facilitate the operation of automated equipment and facilitate large-scale production.

[0078] By cutting both ends of the cylindrical shell 1 made of aluminum-plastic film to form edge sealing 2, and then folding and sealing, it is helpful to release stress during the packaging process, avoid wrinkles on the cylindrical shell 1 at the sealing point, and improve the flatness of the battery appearance and the overall structural stability.

[0079] In one embodiment, the material of the current collecting plate 4 corresponding to the positive electrode is aluminum, and the material of the current collecting plate 4 corresponding to the negative electrode is steel.

[0080] In one embodiment, aluminum-plastic film is used as the shell material, and then through the above-mentioned cutting, flattening and sealing processes, the safety performance of the soft-pack cylindrical battery can be significantly improved, and the risk of explosion caused by excessive internal pressure can be reduced. The design of the conical ear glue 5 also helps to effectively disperse the stress during the battery charging and discharging process and avoid local damage to the film material.

[0081] In one embodiment, the manufacturing method further includes: opening an injection hole 8 on the negative electrode bus; after the step of folding the sealing edge 2 so that the flange is wrapped around the outside of the collecting plate 4 and sealed and connected, it also includes: injecting liquid through the injection hole 8 to form an opening; after the volume separation is completed, the injection port is UV-sealed or hot-melt-sealed with a sealant.

[0082] A liquid injection hole 8 is provided at the negative pole 7, and liquid injection can be performed after the battery cell is assembled without damaging the overall package of the battery. The liquid injection hole 8 can be sealed by ultraviolet glue or hot melt glue after the formation step to ensure the stability of the electrolyte inside the battery and complete the exhaust and volume separation after the battery cell is formed.

[0083] The design of opening the injection hole 8 on the negative electrode busbar facilitates the electrolyte injection and subsequent formation process of the battery. By injecting liquid through the injection hole 8, the injection amount of the electrolyte can be accurately controlled to ensure the uniform distribution of the electrolyte inside the battery, thereby improving the performance and safety of the battery. The negative electrode sealing glue has an injection hole design for liquid injection formation. After the completion, it can be sealed with ultraviolet glue, hot melt glue, etc., to effectively complete the exhaust of the battery cell formation, and seal the battery cell after the capacity division is completed.

[0084] Opening formation refers to the first charge and discharge process of the battery in an incompletely sealed state after the battery is injected with electrolyte. This process helps to activate the active substances inside the battery, and can also detect various performance indicators of the battery after injection, such as internal resistance, capacity, voltage, etc., to ensure the quality of the battery.

[0085] After the capacity division is completed, that is, the battery completes the initial charge and discharge cycle and reaches the designed capacity and voltage range, the injection hole is UV-sealed or hot-melt-sealed with sealant. UV sealing refers to the use of UV-curing glue for sealing. This glue can quickly cure under ultraviolet light and has good sealing and corrosion resistance, which is suitable for the high-demand sealing environment of batteries. Hot-melt sealing uses hot-melt glue. The glue melts under heating conditions and solidifies after cooling to form a seal. Both sealing methods can effectively prevent electrolyte leakage and external air from entering the battery, ensuring the sealing performance and long-term stability of the battery, while also solving the problem of sealing the battery after liquid injection.

[0086] Through the above steps, the method for manufacturing soft-pack cylindrical batteries provided by the present invention not only optimizes the internal structure of the battery and improves the performance of the battery, but also solves the technical problems of traditional cylindrical soft-pack batteries in liquid injection and sealing, and has significant technical advantages and application prospects.

[0087] In one embodiment, the step of cutting at both ends of the cylindrical shell 1 to form a plurality of edge seals 2 arranged in sequence along the circumferential direction includes: determining the size of the edge seal 2 according to the size of the flattened pole ear; and cutting at both ends of the cylindrical shell 1 to form a trapezoidal edge seal 2 with a preset size.

[0088] Cutting to form the edge seal 2 can effectively release the stress of the aluminum-plastic film during the flattening and packaging process, avoiding film wrinkles and possible leakage problems caused by stress concentration. The design of the trapezoidal edge seal 2 further enhances the effect of stress release and ensures the flatness of the aluminum-plastic film during the packaging process.

[0089] The edge sealing 2 after cutting can make the packaged battery look smoother, thus increasing the aesthetics of the product and facilitating the subsequent assembly of the battery, such as assembling it into a battery pack.

[0090] By precisely controlling the size of the edge seal 2, it can be ensured that after the positive and negative electrode tabs are welded to the collector plate 4, the sealing between the cylindrical shell 1 and the collector plate 4 reaches the best state, preventing electrolyte leakage and external air intrusion, thereby improving the overall sealing performance of the battery.

[0091] In one embodiment, the sealing edges 2 at both ends of the cylindrical shell 1 are formed by equidistant cutting. The equidistantly cut sealing edges ensure the uniformity of the sealing at both ends of the battery, improve the sealing quality and overall performance of the battery, and are suitable for all cylindrical soft-pack batteries that require high sealing performance, such as batteries for drones, power tools, etc.

[0092] The equidistantly cut edge seal 2 can better absorb and disperse the stress generated when the pole core is wound, avoiding wrinkles in the aluminum-plastic film during the subsequent flattening and packaging process, thereby improving the flatness and consistency of the package. The cut edge seal 2 can fit the edge of the collector plate 4 more closely when folded and sealed, forming a more uniform and tight sealing ring, reducing the risk of electrolyte leakage and enhancing the sealing performance of the battery. The equidistant cutting of the edge seal 2 helps to maintain the stability of the shell structure, and even during the flattening process, it can ensure that the cylindrical structure of the battery is not easily deformed, ensuring the dimensional accuracy and mechanical properties of the battery.

[0093] In one embodiment, the step of preparing the cylindrical shell 1 includes: integrally forming the cylindrical shell 1 by injection molding; or integrally forming the cylindrical shell 1 by hot pressing.

[0094] Injection molding can provide high dimensional accuracy and surface finish, and is suitable for the production of shells with fixed length and diameter, which helps to ensure the consistency of batteries. Injection molding is suitable for large-scale production, and can quickly and continuously manufacture a large number of shells, reducing production costs. The injection molding process can easily realize the design of complex shapes and structures, such as pre-setting edge sealing structures or center holes on the shell.

[0095] The hot pressing process allows the material to stretch to a certain extent under temperature and pressure. For materials such as aluminum-plastic film, it can better meet the needs of flattening packaging and reduce material stress and wrinkle problems. Hot pressing can provide closer material contact, help improve the sealing effect, and reduce the risk of electrolyte leakage. The hot pressing process is suitable for a variety of materials, including aluminum-plastic film, PP, PE, PET, etc., which can meet the needs of different battery designs.

[0096] 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.

[0097] In one embodiment, the cylindrical shell 1 can be formed by rolling the rectangular film or the rectangular flat plate into a cylindrical shape and performing hot pressing connection at the joint position based on processing the rectangular film or the rectangular flat plate.

[0098] In one embodiment, the cylindrical shell 1 is made of aluminum plastic film, PP, PET or PE.

[0099] The cylindrical shell 1 is made of materials such as aluminum plastic film, PP (polypropylene), PET (polyethylene terephthalate) or PE (polyethylene), which can bring the following effects:

[0100] These materials are light, which helps to reduce the overall weight of the battery. At the same time, the aluminum-plastic film has good packaging properties, which can increase the energy density of the battery while ensuring battery safety, allowing the battery to be designed in a more compact form.

[0101] Aluminum-plastic film and polymer materials have good ductility and toughness. When the internal pressure of the battery increases, these materials can expand instead of rupture. Compared with metal shells, soft-pack batteries are less likely to explode in dangerous situations, thereby improving safety performance.

[0102] Polymer materials such as PP, PET and PE have good flexibility and adaptability, which can adapt to the volume changes of the battery during the charging and discharging process and reduce the damage to the shell caused by changes in the internal pressure of the battery.

[0103] The cost of these materials is relatively low, and they can reduce complex steps such as punching during the manufacturing process, simplifying the production process and reducing production costs.

[0104] Polymer materials are more environmentally friendly than metal shells in post-disposal processing, reducing the difficulty of battery recycling and disposal.

[0105] Due to the characteristics of the material, the shape of the soft-pack battery can be more flexible and can be designed into different shapes according to specific application requirements, such as the cylindrical shape in the present invention, to adapt to different equipment and space requirements.

[0106] See also Figures 2 to 6 As shown, according to an embodiment of the present invention, a cylindrical soft-pack battery is manufactured by the above-mentioned manufacturing method, including: a cylindrical shell 1, both ends of the cylindrical shell 1 are respectively provided with edge seals 2, and multiple edge seals 2 are arranged in sequence along the circumference of the cylindrical shell 1; a pole core 3, which is formed by stacking and winding a positive electrode sheet, a first diaphragm, a negative electrode sheet and a second diaphragm, and the positive and negative pole ears of the pole core 3 are arranged on different sides of the pole core 3, and the pole core 3 is installed in the cylindrical shell 1; a current collecting plate assembly is arranged at the positive end and the negative end of the pole core 3, and is welded to the positive and negative pole ears, and the edge seal 2 is coated on the outside of the current collecting plate assembly and is sealed and connected to the current collecting plate assembly.

[0107] By pre-cutting to form multiple small sealing edges, the stress of the aluminum-plastic film can be dispersed during the packaging process to avoid stress concentration at a certain point causing wrinkles during packaging. This design of dispersing stress can effectively reduce packaging defects caused by insufficient material ductility, especially in the flattening packaging process, and ensure the consistency and stability of battery packaging.

[0108] The multiple sealed edges 2 after cutting can form a closer contact with the collector plate assembly during heat sealing, thereby improving the sealing effect during flattening and packaging. This design ensures that the electrolyte will not leak from the edge of the package, while also preventing external gas from entering the battery, thereby enhancing the overall sealing of the battery and significantly improving the long-term stability and safety performance of the battery.

[0109] The edge sealing and cutting process helps the battery to have a smoother appearance after packaging, reduces appearance defects such as bubbles and dents that may be caused by the ductility and uneven thickness of the aluminum-plastic film, and improves the aesthetics and overall texture of the battery product.

[0110] The design of multiple edge sealing 2 simplifies the packaging process, reduces the process steps, makes the subsequent flattening and packaging process more convenient and efficient, reduces production costs, and improves production efficiency.

[0111] Since the preparation of the cylindrical shell 1 is not limited by the ductility of the material, a shell of any length can be made, which provides greater flexibility for battery design. Battery manufacturers can design cylindrical soft-pack batteries with different axial lengths according to different application requirements, meeting the market demand for battery size diversity.

[0112] The cylindrical shell 1 maintains maximum ductility during the preparation process, which enables the cylindrical soft-pack battery to withstand greater deformation without rupture during use, improves the battery's expansion volume capacity, and thereby increases the battery explosion threshold, thereby enhancing the battery's safety performance.

[0113] In summary, by providing a plurality of circumferentially arranged edge seals 2 at both ends of the cylindrical shell 1, and carefully designing and matching the positive and negative pole ears of the pole core 3 and the current collecting plate assembly, not only can the technical difficulties in the packaging process be effectively solved, but also the performance of the battery can be significantly improved, including enhancing the sealing, improving the appearance, improving the safety performance and increasing the design flexibility.

[0114] In one embodiment, the current collecting plate assembly includes a current collecting plate 4 and a bus bar. The current collecting plate 4 and the bus bar are an integrated structure, and the edge sealing 2 and the bus bar are flattened and sealed by a sealant.

[0115] The positive bus is pre-designed as one with the current collecting plate 4 on the positive side, so that the positive bus and the current collecting plate 4 have better contact, ensuring a larger contact area and lower contact impedance during welding, thereby saving process flow and improving the conductivity of the battery.

[0116] The negative electrode busbar is also designed to be integrated with the current collecting plate 4 on the negative electrode side to achieve the same electrical performance optimization as the positive electrode side.

[0117] After the tabs are flattened, the tabs are connected to the corresponding current collecting plates 4 by laser welding technology. Laser welding can ensure the strength of the welding points while avoiding the thermal damage that may be caused by traditional welding, thereby protecting the internal structure of the battery.

[0118] The edge seal 2 and the bus bar are flattened and sealed by using a sealant. This step is intended to eliminate stress during the packaging process, avoid wrinkles in the cylindrical shell 1, and ensure the sealing performance of the battery.

[0119] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0120] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein.

[0121] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for manufacturing a cylindrical soft-pack battery, characterized in that: include: Preparing a cylindrical shell (1); Cutting at both ends of the cylindrical shell (1) to form a plurality of edge seals (2) arranged in sequence along the circumferential direction; The positive electrode sheet, the first separator, the negative electrode sheet and the second separator are stacked and wound to form a pole core (3), wherein the positive electrode and the negative electrode of the pole core (3) have pole ears on opposite sides; Flatten the positive and negative pole ears; The pole core (3) is installed into the cylindrical housing (1); Welding the current collecting plate (4) to the flattened pole ear; The sealing edge (2) is folded so that the folded edge covers the outside of the current collecting plate (4) and is sealed and connected.

2. The method for manufacturing a cylindrical soft-pack battery according to claim 1, characterized in that: The step of welding the current collecting plate (4) and the flattened pole ear comprises: The positive electrode bus bar and the current collecting plate (4) on the positive electrode side are designed to be integrated; The negative electrode busbar and the current collecting plate (4) on the negative electrode side are designed to be integrated; Welding the flattened electrode tab to the corresponding current collecting plate (4); The steps of folding the sealing edge (2) so that the flange is wrapped around the outside of the current collecting plate (4) and sealed and connected include: The edge seal (2) and the busbar are flattened and sealed by using a sealant.

3. The method for manufacturing a cylindrical soft-pack battery according to claim 2, characterized in that: The step of welding the current collecting plate (4) to the flattened pole ear also includes: After the positive electrode busbar and the current collecting plate (4) on the positive electrode side are designed as an integrated whole, a positive electrode column (6) is designed on the current collecting plate (4), and a pole ear glue (5) is inserted through the positive electrode column (6), the positive electrode column (6) is located on the central axis of the pole ear glue (5), wherein the pole ear glue (5) is conical, and the cross-sectional area increases gradually along the direction approaching the current collecting plate (4); After the negative electrode busbar and the current collecting plate (4) on the negative electrode side are designed as an integrated whole, a negative electrode column (7) is designed on the current collecting plate (4), and a pole ear glue (5) is inserted into the negative electrode column (7), wherein the negative electrode column (7) is located on the central axis of the pole ear glue (5), wherein the pole ear glue (5) is conical, and the cross-sectional area increases gradually along the direction approaching the current collecting plate (4).

4. The method for manufacturing a cylindrical soft-pack battery according to claim 2, characterized in that: The production method also includes: A liquid injection hole (8) is provided on the bus bar of the negative electrode; After the step of folding the sealing edge (2) so that the flange is wrapped around the outside of the current collecting plate (4) and sealed and connected, the method further comprises: Liquid is injected through the liquid injection hole (8) to form an opening; After the volume separation is completed, the liquid injection port is UV-sealed or hot-melt-sealed using sealant.

5. The method for manufacturing a cylindrical soft-pack battery according to claim 1, characterized in that: The step of cutting at both ends of the cylindrical shell (1) to form a plurality of sealed edges (2) arranged in sequence along the circumferential direction comprises: Determine the size of the edge seal (2) according to the size of the flattened tab; Cutting is performed at both ends of the cylindrical shell (1) to form a trapezoidal sealing edge (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 of preparing the cylindrical shell (1) include: The cylindrical housing (1) is integrally formed by injection molding; or The cylindrical shell (1) is integrally formed by hot pressing.

8. The method for manufacturing a cylindrical soft-pack battery according to claim 1, characterized in that: The material of the cylindrical shell (1) is aluminum plastic film, PP, PET or PE.

9. A cylindrical soft-pack battery, manufactured by the manufacturing method according to any one of claims 1 to 8, characterized in that: include: A cylindrical shell (1), wherein both ends of the cylindrical shell (1) are respectively provided with edge seals (2), and a plurality of edge seals (2) are sequentially arranged along the circumference of the cylindrical shell (1); A pole core (3) is formed by stacking and winding a positive electrode sheet, a first separator, a negative electrode sheet and a second separator, wherein the positive and negative electrode tabs of the pole core (3) are arranged on different sides of the pole core (3), and the pole core (3) is installed in the cylindrical shell (1); A current collecting disc assembly is arranged at the positive terminal and the negative terminal of the pole core (3) and is welded to the pole ears of the positive pole and the negative pole. The sealing edge (2) is coated outside the current collecting disc assembly and is sealed and connected to the current collecting disc assembly.

10. The cylindrical soft-pack battery according to claim 9, characterized in that: The current collecting plate assembly comprises a current collecting plate (4) and a bus bar, the current collecting plate (4) and the bus bar are an integrated structure, and the edge sealing (2) and the bus bar are flattened and sealed by a sealant.

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