A cell winding process, a cell winding device, a cell, a battery, and an electric device

Abstract

The application relates to a cell winding process, a cell winding device, a cell, a battery and a power utilization device, wherein the cell winding process comprises the following steps: winding starting, fixing the starting end of a separator layer, a cathode pole piece and an anode pole piece on a winding device for cell winding, and arranging the separator layer between the cathode pole piece and the anode pole piece; heating, arranging a heating part on the winding device, and heating the heating area of the separator layer by the heating part; winding, arranging a winding needle on the winding device, and winding the heated separator layer, the cathode pole piece and the anode pole piece through the winding needle. The application heats the separator layer, melts the PCS polymer on the separator layer, tightly bonds and fixes the cathode pole piece and the anode pole piece on the separator layer, and prevents the gap caused by the retraction of the pole piece due to stress release after winding is completed. Therefore, the problem of lithium precipitation on the anode surface caused by the long lithium ion transmission path during charging and discharging can be prevented, and the safety performance of the battery is improved.

Description

Technical Field

[0001] This invention relates to the field of lithium-ion battery technology, and in particular to a cell winding process, a cell winding device, a cell, a battery, and an electrical device. Background Technology

[0002] Lithium-ion batteries are increasingly used in the market due to their advantages such as high energy density, high output power, long cycle life, and low environmental pollution.

[0003] Lithium-ion batteries, including wound batteries, are composed of cells assembled in a wound manner. Compared to flat-plate batteries, wound batteries are made by high-voltage winding of electrode plates that are only about 1mm thick. Through special processes, these batteries possess characteristics such as superior high-rate discharge capability, excellent high and low temperature performance, stable high output voltage, and higher energy density.

[0004] However, during high-voltage winding of wound batteries, gaps can easily appear at the bends between the cathode and anode plates, causing lithium plating. Furthermore, if material falls out from the bends, the lithium plating situation will be further aggravated, posing a safety hazard of internal short circuits in the battery. Summary of the Invention

[0005] Therefore, it is necessary to provide a cell winding process, a cell winding device, a cell, a battery, and an electrical device to address the problem of lithium plating caused by gaps easily occurring between the cathode and anode plates of wound batteries in the prior art.

[0006] In a first aspect, this application provides a battery cell winding process, including the following steps:

[0007] The starting point of the winding process involves fixing the diaphragm layer, cathode electrode, and anode electrode onto a winding device for winding the battery cell, with the diaphragm layer positioned between the cathode electrode and the anode electrode.

[0008] Heating: A heating section is provided on the winding device, which heats the heating areas on the two surfaces of the diaphragm layer that are respectively attached to the cathode and anode plates;

[0009] The winding device is equipped with winding needles to wind the heated diaphragm layer, cathode electrode, and anode electrode.

[0010] Since the separator layer is located between the cathode and anode plates, heating the separator layer towards the heating areas on the two surfaces of the cathode and anode plates respectively will melt the PCS (polycarbosilane) polymer on it. Then, it can be wound up to make the cathode and anode plates tightly bonded to the separator layer.

[0011] Therefore, the cathode and anode electrodes can be bonded and fixed through the structure of the diaphragm layer itself, without the need for additional bonding structures. This simplifies the cell structure to the greatest extent, reduces the thickness of the wound cell, and decreases the cell volume.

[0012] In some embodiments, during the heating step, the heating area is located on the side of the diaphragm layer parallel to the winding direction, and the width of the heating area ranges from 2 mm to 4 mm.

[0013] When the heating width is less than 2mm, the adhesion between the cathode and anode plates and the separator layer is poor due to the small bonding width, making it impossible to fix the cathode and anode plates in place. When the heating width is greater than 4mm, it will affect the insertion and extraction of lithium ions in the bonding area, thereby deteriorating the cell performance.

[0014] In some embodiments, during the heating step, the heating area is located on the side of the separator layer parallel to the winding direction, and the length of the heating area is at least three turns. If the heating length is less than three turns, the cathode and anode plates cannot be effectively bonded to the separator layer, and the fixing effect is not achieved.

[0015] In some embodiments, the heating temperature of the heating element in the heating step is 90°C-130°C.

[0016] Specifically, when the heating temperature exceeds 130°C, the melting of the separator layer can easily block the original micropores on the separator layer, affecting the transfer of lithium ions during charging and discharging, thereby deteriorating the battery's resistance, capacity, and cycle performance. When the heating temperature is below 90°C, the PCS polymer on the separator layer cannot be melted, and it cannot play a role in bonding and fixing.

[0017] In some embodiments, the cell winding process further includes the following step after the winding step:

[0018] After the pre-compression and winding steps are completed, the battery cell is obtained. The winding needle is pulled out of the battery cell and pressure is applied for pre-compression to shape and bind the battery cell electrode sheets.

[0019] After the winding needles are pulled out of the cell, the multiple layers of electrodes will shrink back due to stress release. To avoid this, applying appropriate pressure to the wound cell for pre-compression can act as a shaping and binding agent, improving the cell's performance.

[0020] In some embodiments, the winding apparatus includes a plurality of winding rollers for transporting the diaphragm layer, all of which are spaced apart along the transport direction of the diaphragm layer. The transport and transfer of the diaphragm layer, the cathode electrode, and the anode electrode can be achieved by means of the plurality of winding rollers.

[0021] In some embodiments, during the heating step, the heating element is located on one of the winding rollers closest to the winding needle. This ensures that the heating temperature on the diaphragm layer is maintained, preventing failure to bond and fix due to cooling.

[0022] Secondly, this application provides a battery cell winding apparatus for operating the battery cell winding process described above. The battery cell winding apparatus includes a winding device for winding the battery cell, and a heating part is provided on the winding device to heat the heating areas on the two surfaces of the separator layer that are respectively attached to the cathode electrode and the anode electrode.

[0023] In some embodiments, the heating element is located at the edge of the diaphragm layer parallel to the winding direction, and the heating width ranges from 2 mm to 4 mm.

[0024] In some embodiments, the heating element is located at the edge of the diaphragm layer parallel to the winding direction, and the heating length is at least three turns.

[0025] In some embodiments, the heating temperature of the heating element is in the range of 90°C-130°C.

[0026] In some embodiments, the winding apparatus includes a plurality of winding rollers for transporting the diaphragm layer, all of which are spaced apart along the transport direction of the diaphragm layer.

[0027] In some embodiments, the heating element is located on one of the plurality of winding rollers near the winding needle.

[0028] Thirdly, this application provides a battery cell manufactured by the battery cell winding process described above.

[0029] Fourthly, this application provides a battery, including a housing and the aforementioned battery cell, the battery cell being disposed within the housing.

[0030] Fifthly, this application provides an electrical device, including an electrical main body and the battery as described above.

[0031] The aforementioned cell winding process, cell winding device, cell, battery, and power-consuming device heat the separator layer through a heating element, causing the PCS polymer on the separator layer to melt at high temperature. This melts the PCS polymer and acts as a bond for the cathode and anode electrodes, ensuring a tight bond between them. This prevents gaps from forming due to stress release after winding. Consequently, it prevents lithium deposition on the anode surface caused by excessively long lithium-ion transport paths during charging and discharging, further improving battery safety. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the structure of a vehicle according to an embodiment of this application;

[0033] Figure 2This is a schematic diagram of the structure of a battery according to an embodiment of this application;

[0034] Figure 3 This is a schematic diagram of the structure of a battery cell according to an embodiment of this application;

[0035] Figure 4 This is a schematic diagram of the battery cell structure in one embodiment of this application;

[0036] Figure 5 for Figure 4 A schematic diagram of the structure of the battery cell during winding;

[0037] Figure 6 for Figure 4 The diagram shows the structure of the separator layer in the battery cell.

[0038] In the diagram: 1000-vehicle, 100-battery, 200-controller, 300-motor, 10-box, 20-cell, 11-first part, 12-second part, 21-end cap, 22-shell, 23-cell assembly, 24-separator layer, 25-cathode plate, 26-anode plate, 27-winding device, 21a-electrode terminal, 23a-tab, 241-heating area, 271-heating part, 272-winding needle, 273-winding roller. Detailed Implementation

[0039] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0040] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0041] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0042] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0043] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0044] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0045] Currently, from a market perspective, lithium-ion batteries are widely used in electric vehicles and consumer electronics due to their advantages such as high energy density, high output power, long cycle life, and low environmental pollution. As the application areas of lithium-ion batteries continue to expand, the market demand is also constantly increasing.

[0046] The production process of lithium-ion batteries typically includes the following steps: First, electrode slurry preparation, which involves mixing electrode active materials, binders, solvents, etc., and thoroughly stirring and dispersing them to form a slurry. Second, coating, where the slurry prepared in the first step is uniformly coated to a current collector (aluminum foil or copper foil, etc.) to a specified thickness, and the solvent is dried. Third, electrode die-cutting, where the electrode sheets produced in the previous step are die-cut to a specified size and shape. Fourth, stacking, where the anode and cathode electrodes and separator are assembled together, and after adhesive bonding, an electrode core is formed. Fifth, assembling the pouch cell, where the electrode core produced in the previous step is inserted into a pre-punched aluminum-plastic film, and top and side seals are completed (leaving an opening for electrolyte injection), forming an unfilled pouch cell. Sixth, electrolyte injection, where a specified amount of electrolyte is injected into the pouch cell. Seventh, battery sealing, where the gas inside the cell is extracted in a vacuum environment and sealed.

[0047] Furthermore, lithium-ion batteries are divided into wound batteries and flat batteries. Among them, wound batteries also have a winding step in the above-mentioned stacking steps, in which the anode and cathode sheets are attached to the separator and wound together to form a wound battery, and then proceed to the next assembly step.

[0048] Wound batteries are manufactured using high-voltage winding of plates only about 1mm thick, employing specialized processes. Therefore, compared to flat-plate batteries, they possess the following characteristics: 1. Superior high-rate discharge capability; 2. Excellent high and low temperature performance; 3. Stable high output voltage; 4. Higher energy density; 5. Excellent shock resistance; 6. Fast charging and longer lifespan. Consequently, wound batteries are finding increasingly widespread application in the market.

[0049] With the widespread use of wound batteries, the performance requirements for them are also increasing. For greater ease of use, wound batteries are demanding higher energy density and smaller size. Consequently, the pressure applied during the pressing process after the battery is wound is significantly greater.

[0050] However, the inventors discovered that as the pressure during lamination increases, the bending angle of the bent portion of the wound battery becomes smaller and smaller. This results in a decreasing bending angle at the bending portions of the cathode and anode electrodes, significantly increasing the probability of coating peeling off at the bending points, thereby increasing the risk of lithium plating in the battery.

[0051] Furthermore, the inventors noted that the separator layer contains a PCS polymer, specifically PVDF (polyvinylidene fluoride). This component melts at a certain temperature, and upon melting, it imparts an adhesive effect to the separator layer. Based on this, the inventors conceived that if the PCS polymer on the separator layer were melted under specific conditions, it could bond and fix the cathode and anode electrodes together, solving the bonding problem between the cathode and anode electrodes without requiring additional external structures. This simplifies the structure of the wound battery, allowing it to have a smaller volume after pressing.

[0052] Based on the above considerations, in order to reduce the volume of the wound battery and solve the problem of lithium plating caused by gaps in the bending parts of the cathode and anode electrodes, the inventors, after in-depth research, designed a cell winding process. By utilizing the structure of the separator layer itself and through special processing methods, the volume of the wound battery can be reduced, and the problem of lithium plating and short circuits in the wound battery can be solved.

[0053] The battery cells disclosed in this application can be used, but are not limited to, in electrical devices such as vehicles, ships, or aircraft. A power system for such an electrical device can be constructed using the battery cells and batteries disclosed in this application. This facilitates the bonding and fixing of the cathode and anode plates, preventing gaps between them that could lead to lithium plating, and preventing excessively long lithium-ion transport paths during charging and discharging, thus further improving battery safety.

[0054] This application provides an electrical device that uses a battery as a power source. The electrical device can be, but is not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric vehicles, electric cars, ships, spacecraft, etc. Electric toys can include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.

[0055] For ease of explanation, the following embodiments use a vehicle 1000 as an example of an electrical device according to an embodiment of this application.

[0056] Please refer to Figure 1 , Figure 1This is a schematic diagram of the structure of a vehicle 1000 provided in some embodiments of this application. The vehicle 1000 can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. New energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. A battery 100 is disposed inside the vehicle 1000, and the battery 100 can be located at the bottom, front, or rear of the vehicle 1000. The battery 100 can be used to power the vehicle 1000; for example, the battery 100 can serve as the operating power source for the vehicle 1000. The vehicle 1000 may also include a controller 200 and a motor 300. The controller 200 is used to control the battery 100 to supply power to the motor 300, for example, to meet the power needs of the vehicle 1000 during startup, navigation, and driving.

[0057] In some embodiments of this application, the battery 100 can not only serve as the operating power source for the vehicle 1000, but also as the driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0058] Please refer to Figure 2 , Figure 2 This is a schematic diagram of a battery structure provided in one embodiment of this application. The battery 100 includes a housing 10 and a battery cell 20, with the battery cell 20 housed within the housing 10. The housing 10 provides a space for the battery cell 20, and can have various structures. In some embodiments, the housing 10 may include a first portion 11 and a second portion 12, which overlap each other, jointly defining a space for accommodating the battery cell 20. The second portion 12 may be a hollow structure with one open end, and the first portion 11 may be a plate-like structure, covering the open side of the second portion 12 so that the first portion 11 and the second portion 12 jointly define the space. Alternatively, both the first portion 11 and the second portion 12 may be hollow structures with one open side, with the open side of the first portion 11 covering the open side of the second portion 12. Of course, the housing 10 formed by the first portion 11 and the second portion 12 can have various shapes, such as a cylinder, a cuboid, etc.

[0059] In battery 100, there can be multiple cells 20, which can be connected in series, parallel, or a combination thereof. A combination thereof means that multiple cells 20 are connected in both series and parallel configurations. Multiple cells 20 can be directly connected in series, parallel, or a combination thereof, and then the entire assembly of the multiple cells 20 is housed within housing 10. Alternatively, battery 100 can also consist of multiple cells 20 first connected in series, parallel, or a combination thereof to form battery modules, and then these battery modules are connected in series, parallel, or a combination thereof to form a whole, which is then housed within housing 10. Battery 100 may also include other structures; for example, it may include a busbar component for electrical connection between the multiple cells 20.

[0060] Please refer to Figure 3 , Figure 3 This is a schematic diagram of the structure of a battery cell provided in one embodiment of this application. Each battery cell 20 can be a secondary battery or a primary battery; it can also be a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery, but is not limited to these. The battery cell 20 can be cylindrical, flat, cuboid, or other shapes. Specifically, the battery cell 20 refers to the smallest unit that makes up the battery, and the battery cell 20 includes an end cap 21, a housing 22, a cell assembly 23, and other functional components.

[0061] End cap 21 refers to a component that covers the opening of housing 22 to isolate the internal environment of battery cell 20 from the external environment. The shape of end cap 21 can be adapted to the shape of housing 22 to fit it. Optionally, end cap 21 can be made of a material with certain hardness and strength (such as aluminum alloy), so that end cap 21 is not easily deformed under pressure and impact, giving battery cell 20 higher structural strength and improved safety performance. Functional components such as electrode terminals 21a can be provided on end cap 21. Electrode terminals 21a can be used for electrical connection with battery cell assembly 23 to output or input electrical energy to battery cell 20. In some embodiments, end cap 21 can also be provided with a pressure relief mechanism for releasing internal pressure when the internal pressure or temperature of battery cell 20 reaches a threshold. The material of end cap 21 can also be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and this application embodiment does not impose special limitations on this. In some embodiments, an insulating element may be provided on the inner side of the end cap 21. The insulating element can be used to isolate the electrical connection components within the housing 22 from the end cap 21 to reduce the risk of short circuits. For example, the insulating element may be made of plastic, rubber, etc.

[0062] The housing 22 is a component used to cooperate with the end cap 21 to form the internal environment of the battery cell 20. This internal environment can accommodate the battery cell assembly 23, electrolyte, and other components. The housing 22 and the end cap 21 can be independent components. An opening can be provided on the housing 22, and the end cap 21 can be used to close the opening to form the internal environment of the battery cell 20. Alternatively, the end cap 21 and the housing 22 can be integrated. Specifically, the end cap 21 and the housing 22 can form a common connecting surface before other components are inserted into the housing. When it is necessary to encapsulate the interior of the housing 22, the end cap 21 closes the housing 22. The housing 22 can be of various shapes and sizes, such as cuboid, cylindrical, hexagonal prism, etc. Specifically, the shape of the housing 22 can be determined according to the specific shape and size of the battery cell assembly 23. The material of the housing 22 can be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc. This embodiment does not impose any special limitations on this.

[0063] The cell assembly 23 is the component in the cell 20 where the electrochemical reaction occurs. The housing 22 may contain one or more cell assemblies 23. The cell assembly 23 is mainly formed by winding or stacking cathode and anode plates, and typically a separator is provided between the cathode and anode plates. The portions of the cathode and anode plates containing active material constitute the main body of the cell assembly 23, while the portions of the cathode and anode plates without active material each constitute a tab 23a. The cathode tab and anode tab may be located together at one end of the main body or separately at both ends of the main body. During the charging and discharging process of the battery, the cathode active material and the anode active material react with the electrolyte, and the tab 23a connects to the electrode terminal 21a to form a current loop.

[0064] Figure 4 A schematic diagram of the battery cell structure according to an embodiment of the present invention is shown. Figure 5 This diagram illustrates the structure of a battery cell during winding according to an embodiment of the present invention. Figure 6 A schematic diagram of the membrane layer in one embodiment of the present invention is shown. For ease of description, the accompanying drawings only show structures relevant to embodiments of the present invention.

[0065] Please see Figure 4 , Figure 5 as well as Figure 6 As shown, an embodiment of the present invention provides a cell winding process, including the following steps:

[0066] S10: Start winding, fix the starting ends of the separator layer 24, the cathode electrode 25 and the anode electrode 26 on the winding device 27 for winding the battery cell, and place the separator layer 24 between the cathode electrode 25 and the anode electrode 26.

[0067] S20: Heating. A heating part 271 is provided on the winding device 27. The heating part 271 heats the heating areas 241 on the two surfaces of the diaphragm layer 24 that are respectively attached to the cathode electrode 25 and the anode electrode 26.

[0068] Since the diaphragm layer 24 is located between the cathode electrode 25 and the anode electrode 26, the diaphragm layer 24 is heated toward the heating area 241 on the two surfaces of the cathode electrode 25 and the anode electrode 26 respectively, so that the PCS polymer on it melts and is then wound, so that the cathode electrode 25 and the anode electrode 26 can be tightly bonded to the diaphragm layer 24.

[0069] It should be noted that the heating element 271 can be configured as a heating plate, which is attached to the diaphragm layer 24 by the winding device 27, thereby heating the diaphragm layer 24. Understandably, the heating element 271 can also be configured as other heating structures, such as heating tubes, infrared heaters, etc., which will not be described in detail here.

[0070] Furthermore, in the heating step, the heating region 241 is located on the side of the diaphragm layer 24 parallel to the winding direction, and the width of the heating region 241 ranges from 2mm to 4mm.

[0071] Specifically, in this embodiment, the heating region 241 is located at the edge of the separator layer 24 and extends inward by 2mm-4mm from the edge. Furthermore, there are typically two heating regions 241, located on the two sides of the separator layer 24, each with a width of 2mm-4mm. This heating of both the left and right edges of the separator layer 24 allows for a tighter fit between the cathode electrode 25 and the anode electrode 26 and the separator layer 24.

[0072] Furthermore, experimental verification showed that when the width of the heating area 241 is less than 2 mm, the adhesion between the cathode electrode 25, anode electrode 26, and separator layer 24 is poor due to the insufficient width of the bonding, making it impossible to fix the cathode electrode 25 and anode electrode 26. When the width of the heating area 241 is greater than 4 mm, it will affect the insertion and extraction of lithium ions in the bonding area, thereby deteriorating the cell performance.

[0073] Furthermore, in the heating step, the length of the heating region 241 is at least three turns. That is, the length of the heating region 241 on the diaphragm layer 24 should be sufficient to allow the cathode electrode 25, the diaphragm layer 24, and the anode electrode 26 to be wound together at least three turns. If the length of the heating region 241 is less than three turns, the cathode electrode 25 and the anode electrode 26 cannot be effectively bonded to the diaphragm layer, and the fixing effect is not achieved.

[0074] Furthermore, in the heating step, the heating temperature range of the heating section 271 is 90℃-130℃. Specifically, since the separator layer 24 has a fibrous structure with several tiny through-holes distributed on it, these through-holes provide channels for the transfer of lithium ions. When the heating temperature exceeds 130℃, the separator layer 24 melts, which can easily block the original micropores on it, affecting the transfer of lithium ions during charging and discharging, thereby deteriorating the battery's resistance, capacity, and cycle performance. When the heating temperature is below 90℃, the PCS polymer on the separator layer 24 cannot be melted, and it cannot play a role in bonding and fixing.

[0075] S30: Winding. A winding needle 272 is provided on the winding device 27 to wind the heated diaphragm layer 24, the cathode electrode 25, and the anode electrode 26 through the winding needle 272.

[0076] S40: Pre-compression. After the winding step is completed, the battery cell is obtained. The winding needle 272 is pulled out from the battery cell and pressure is applied for pre-compression to shape and bind the battery cell electrode sheets.

[0077] Specifically, after winding is completed and the winding needle 272 is pulled out of the cell, the multiple layers of electrodes will shrink back due to stress release. To avoid this, applying appropriate pressure to the wound cell for pre-compression can play a shaping and binding role, thereby improving the cell's performance.

[0078] The winding device 27 in the above-mentioned battery cell winding process includes multiple winding rollers 273 for transporting the separator layer, and all winding rollers 273 are spaced apart along the transport direction of the separator layer 24. Specifically, in this embodiment, the separator layer 24, the cathode electrode 25, and the anode electrode 26 each correspond to multiple winding rollers 273. Since the separator layer 24, the cathode electrode 25, and the anode electrode 26 are relatively long before winding, multiple winding rollers 273 are needed to transport and transfer the separator layer 24, the cathode electrode 25, and the anode electrode 26.

[0079] Furthermore, the heating element 271 is provided on one of the winding rollers 273 closest to the winding needle 272. That is, the heating element 271 is provided on the winding roller 273 closest to the winding needle 272, thereby preventing the diaphragm layer 24 from cooling down during transportation after heating, which would cause it to fail to be fixed.

[0080] Based on the same concept as the above-described battery cell winding process, the present invention also provides a battery cell winding apparatus for operating the above-described battery cell winding process, including a winding apparatus 27 for winding the battery cell. The winding apparatus 27 is provided with a heating section 271 to heat the heating areas 241 on the two surfaces of the separator layer 24 that are respectively attached to the cathode electrode 25 and the anode electrode 26.

[0081] Specifically, in this embodiment, during cell winding, the separator layer 24 is placed between the cathode electrode 25 and the anode electrode 26 to isolate them. Further, the heating regions 241 on the two surfaces of the separator layer 24 facing the cathode electrode 25 and the anode electrode 26 are heated to melt the PCS polymer on them. Therefore, during winding, the separator layer 24 has adhesive properties on both sides facing the cathode electrode 25 and the anode electrode 26. Thus, the cathode electrode 25 and the anode electrode 26 can be tightly bonded to the separator layer 24 during the winding process.

[0082] It should be noted that the heating element 271 can be configured as a heating plate, which is attached to the diaphragm layer 24 by the winding device 27, thereby heating the diaphragm layer 24. Understandably, the heating element 271 can also be configured as other heating structures, such as heating tubes, infrared heaters, etc., which will not be described in detail here.

[0083] In some embodiments, the heating part 271 is located at the edge of the diaphragm layer 24 parallel to the winding direction, and the heating width is 2mm-4mm.

[0084] Specifically, in this embodiment, the edge of the diaphragm layer 24 is heated by the heating unit 271, with a heating width of 2mm-4mm. During winding, the edges of the cathode electrode 25 and the anode electrode 26 can be tightly bonded to the diaphragm layer 24, thereby achieving a fixed connection. Furthermore, the heating unit 271 heats both side edges of the diaphragm layer 24 along the winding direction, with a heating width of 2mm-4mm on both sides. This ensures that both sides of the diaphragm layer 24 have adhesive strength.

[0085] Furthermore, experimental verification showed that when the heating width is less than 2mm, the adhesion between the cathode electrode 25, anode electrode 26, and separator layer 24 is poor due to the insufficient bonding width, making it impossible to fix the cathode electrode 25 and anode electrode 26. When the heating width is greater than 4mm, it will affect the insertion and extraction of lithium ions in the bonding area, thereby deteriorating the cell performance.

[0086] Furthermore, the heating length of the heating section 271 is at least three turns. That is, the heating length of the heating section 271 on the diaphragm layer 24 should be sufficient to allow the cathode electrode 25, the diaphragm layer 24, and the anode electrode 26 to be wound together at least three turns. If the heating length is less than three turns, the cathode electrode 25 and the anode electrode 26 cannot be effectively bonded to the diaphragm layer 24, and the fixing effect cannot be achieved.

[0087] Furthermore, the heating temperature range of the heating section 271 is 90℃-130℃. Specifically, since the separator layer 24 has a fibrous structure with several tiny through-holes distributed on it, these through-holes provide channels for the transfer of lithium ions. When the heating temperature exceeds 130℃, the separator layer 24 melts, which can easily block the original micropores on it, affecting the transfer of lithium ions during charging and discharging, thereby deteriorating the battery's resistance, capacity, and cycle performance. When the heating temperature is below 90℃, the PCS polymer on the separator layer 24 cannot be melted, and it cannot play a role in bonding and fixing.

[0088] In some embodiments, the winding device 27 includes a plurality of winding rollers 273 for transporting the diaphragm layer 24, all of which are spaced apart along the transport direction of the diaphragm layer 24.

[0089] Specifically, in this embodiment, the diaphragm layer 24, the cathode electrode 25, and the anode electrode 26 correspond to multiple winding rollers 273. Since the diaphragm layer 24, the cathode electrode 25, and the anode electrode 26 are relatively long before winding, multiple winding rollers 273 are needed to transport and transfer the diaphragm layer 24, the cathode electrode 25, and the anode electrode 26.

[0090] Furthermore, the heating element 271 is provided on one of the winding rollers 273 closest to the winding needle 272. That is, the heating element 271 is provided on the winding roller 273 closest to the winding needle 272, thereby preventing the diaphragm layer 24 from cooling down during transportation after heating, which would cause it to fail to be fixed.

[0091] Based on the same concept as the above-described battery cell winding device, the present invention also provides a battery cell that can be manufactured by the battery cell winding process described above.

[0092] Based on the same concept as the aforementioned battery cell, the present invention also provides a battery, including a housing and a battery cell as described above, wherein the battery cell is disposed within the housing.

[0093] Based on the same concept as the battery described above, the present invention also provides an electrical device, including an electrical main body and the battery described above.

[0094] In practical use, the present invention firstly involves providing a heating section 271 on one of the multiple winding rollers 273 corresponding to the diaphragm layer 24, the one closest to the winding needle 272. This allows the heating section to heat both sides of the edge of the diaphragm layer 24, with the heating width range set to 2mm-4mm.

[0095] Next, the diaphragm layer 24, the cathode electrode 25, and the anode electrode 26 are respectively fixed onto their respective winding rollers 273, and the diaphragm layer 24, the cathode electrode 25, and the anode electrode 26 are transferred onto the winding needle 272 by the guidance of the winding rollers 273. During this process, the diaphragm layer 24 must be kept between the cathode electrode 25 and the anode electrode 26.

[0096] After the diaphragm layer 24, cathode electrode 25, and anode electrode 26 are fixed, the winding process can begin. Simultaneously, the heating temperature of the heating unit 271 is controlled between 90℃ and 130℃, and the diaphragm layer 24 is heated concurrently during the winding process. The heated diaphragm layer 24 adheres to the cathode electrode 25 and anode electrode 26 respectively during the winding process, thereby achieving a fixing effect.

[0097] After the battery cell is wound, the winding needle 272 is pulled out of the battery cell and a certain pressure is applied to pre-compress the battery cell. This serves to shape and bind the battery cell electrodes, preventing the gaps between the electrodes from widening during the production process.

[0098] The cell winding process, cell winding device, cell, battery, and power-consuming device described in the above embodiments have at least the following advantages:

[0099] 1) Heating the diaphragm layer 24 melts the PCS polymer on it, giving it an adhesive function, thereby fixing the cathode electrode 25 and the anode electrode 26. The electrode is bonded and fixed through the structure of the diaphragm layer 24 itself. The operation process is simple and the work efficiency is high.

[0100] 2) Since the bonding is achieved by utilizing the structure of the separator layer 24 itself, there is no need to add other bonding structures, which can simplify the structure of the cell to the greatest extent, reduce the thickness of the cell after winding, and thus reduce the cell volume and improve the cell performance.

[0101] 3) Pre-pressing the wound cell can prevent the shrinkage phenomenon between the multi-layer electrode sheets due to stress release after the winding needle 272 is pulled out of the cell, thereby playing a shaping and binding role on the cell electrode sheets and improving the cell performance.

[0102] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0103] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. An electrode core winding process, characterized by, The method comprises the steps of: starting winding, fixing the starting end of the separator layer, the cathode electrode sheet and the anode electrode sheet on a winding device for winding the battery cell, and the separator layer is arranged between the cathode electrode sheet and the anode electrode sheet; heating, the winding device is provided with a heating part, and the heating part heats the heating area on the two surfaces of the separator layer respectively adhered to the cathode electrode sheet and the anode electrode sheet; wherein the heating area is located on the side edge of the separator layer parallel to the winding direction, and the width of the heating area ranges from 2mm to 4mm; winding, the winding device is provided with a winding needle, and the heated separator layer, the cathode electrode sheet and the anode electrode sheet are wound by the winding needle.

2. The cell winding process of claim 1, wherein, In the heating step, the heating area is located on the side edge of the separator layer parallel to the winding direction, and the length of the heating area is at least three turns.

3. The cell winding process of claim 1, wherein, In the heating step, the heating temperature of the heating part ranges from 90℃ to 130℃.

4. The cell winding process of claim 1, wherein, The battery cell winding process further comprises the step of: pre-pressing, after the winding step, the winding needle is pulled out of the battery cell, and a pressure is applied for pre-pressing to shape and bind the electrode sheet of the battery cell.

5. The cell winding process of claim 1, wherein, The winding device comprises a plurality of winding rollers for conveying the separator layer, and all the winding rollers are arranged at intervals along the conveying direction of the separator layer.

6. The cell winding process of claim 5, wherein, In the heating step, the heating part is arranged on one of the winding rollers close to the winding needle.

7. An electrode core winding device characterized by comprising: The battery cell winding device for operating the battery cell winding process as claimed in any one of claims 1-6 comprises a winding device for winding the battery cell, and the winding device is provided with a heating part to heat the heating area on the two surfaces of the separator layer respectively adhered to the cathode electrode sheet and the anode electrode sheet.

8. An electric cell characterized by Prepared by the battery cell winding process as claimed in any one of claims 1-6.

9. A battery, characterized by The battery cell as claimed in claim 8 is arranged in the housing.

10. An electrical device, characterized by The battery as claimed in claim 9 is used by the main body.

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