Battery cell, method of coating an electrode assembly, and coating apparatus

Abstract

The application provides a battery monomer, a coating method and a coating device of an electrode assembly, and belongs to the battery field. The battery monomer comprises an electrode assembly and an insulating film, the insulating film is wound and coated on the outer periphery of the electrode assembly, the insulating film has a winding starting end and a winding ending end along the winding direction of the insulating film, and the winding starting end and the winding ending end at least partially overlap; the insulating film comprises a glue coating area and an empty film area, at least one end of the glue coating area along the winding direction is connected with the empty film area, the glue coating area is arranged on at least part of the outer periphery of the electrode assembly, and at most one of the winding starting end and the winding ending end comprises part of the glue coating area. In the scheme, the insulating film can play an insulating protection role, and the restraint on the electrode assembly is not too tight.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to a method and apparatus for coating a battery cell and an electrode assembly. Background Technology

[0002] Energy conservation and emission reduction are crucial for sustainable social development. Batteries, with their ability to store or release energy as needed, are widely used in various electrical devices and energy storage systems, and are an important component in promoting energy transition and sustainable development. For the new energy industry, battery technology is a critical factor in its development.

[0003] To ensure insulation between the electrode assembly and the battery casing, an insulating film is typically used to cover the electrode assembly. A key concern is how to ensure that the insulating film provides adequate insulation without excessively restricting the electrode assembly. Summary of the Invention

[0004] This application aims to at least address one of the technical problems existing in the background art. Therefore, one objective of this application is to provide a method and apparatus for coating battery cells and electrode assemblies, achieving a good balance between insulation protection and binding degree.

[0005] An embodiment of the first aspect of this application provides a battery cell, including: an electrode assembly and an insulating film. The insulating film is wound around the outer periphery of the electrode assembly. The insulating film has a winding start end and a winding end end along its own winding direction, and the winding start end and the winding end end at least partially overlap. The insulating film includes an adhesive coating area and an empty film area. At least one end of the adhesive coating area along the winding direction is connected to the empty film area. The adhesive coating area is disposed on at least a portion of the outer periphery of the electrode assembly, and at most one of the winding start end and the winding end end includes a portion of the adhesive coating area.

[0006] In the technical solution of this application embodiment, the outer peripheral surface of the electrode assembly is covered by an insulating film, making the insulating film reliably insulating and protecting the electrode assembly. Simultaneously, by including at most one of the winding start end and winding end portion in the adhesive coating area, the adhesive coating areas do not overlap along the winding direction. Therefore, the adhesive layer in the overlapping area of ​​the insulating film is at most one layer. Without changing the thickness of the substrate and adhesive layer, the thickness of the overlapping area of ​​the insulating film is reduced, thus lessening the constraint of the overlapping area of ​​the insulating film on the electrode assembly. In this way, a good balance is achieved between the insulating and protective effect of the insulating film on the electrode assembly and the degree of constraint imposed by the insulating film on the electrode assembly.

[0007] In some embodiments, the insulating film includes two empty film regions, which correspond one-to-one with and are connected to the two ends of the adhesive coating region along the winding direction. Using this technical solution, without changing the dimensions of the adhesive coating region and the empty film regions, the insulating film in this embodiment has a larger allowance, enabling it to reliably cover the outer periphery of the electrode assembly.

[0008] In some embodiments, the one closer to the center of the electrode assembly among the two empty film regions is used as the winding start end. In this embodiment, since the winding start end only includes the empty film region, the thickness of more of the overlapping area of ​​the insulating film is reduced, which is beneficial to further weaken the binding force of the insulating film on the electrode assembly.

[0009] In some embodiments, the winding end includes a portion of the adhesive coating area, which helps to prevent the overlapping parts of the insulating film from loosening and improves the winding tightness of the insulating film.

[0010] In some embodiments, the dimension of the coating area along the winding direction is a first dimension, and the perimeter of the outer contour of the electrode assembly is a second dimension, wherein the first dimension is 80% to 99% of the second dimension.

[0011] In this embodiment, the ratio of the first dimension to the second dimension is within the aforementioned range, which is beneficial for increasing the area of ​​the adhesive coating region and improving the reliability of the insulating film's coverage of the electrode assembly.

[0012] In some embodiments, the sum of the dimensions of all empty membrane regions along the winding direction is the third dimension, and the ratio of the third dimension to the first dimension is 1:4 to 1:50.

[0013] An embodiment of the second aspect of this application provides a method for coating a battery cell, comprising: providing an electrode assembly; providing an insulating film, wherein the insulating film includes a coating region and an empty film region, at least one end of the coating region along a first direction is connected to the empty film region, the first direction being perpendicular to the thickness direction of the coating region; and winding the insulating film around the outer periphery of the electrode assembly, wherein the coating region and the empty film region are successively wound onto the electrode assembly, and the starting end and the ending end of the winding of the insulating film along its own winding direction at least partially overlap, wherein the coating region is disposed on at least a portion of the outer periphery of the electrode assembly, and at most one of the starting end and the ending end of the winding includes a portion of the coating region.

[0014] In some embodiments, providing an insulating film includes: providing an insulating film core, wherein the insulating film core includes a plurality of insulating films sequentially connected along the length direction of the insulating film core, the insulating film including an adhesive coating area and an empty film area, the adhesive coating area being connected to at least one end of the empty film area along the length direction of the insulating film core; unwinding the insulating film core into a strip film; cutting a first insulating film on the strip film from the strip film, wherein, along the conveying path of the strip film, the first insulating film is the foremost insulating film of the strip film.

[0015] In some embodiments, the first insulating film includes two empty film regions, which are a first empty film region and a second empty film region, respectively, with the first empty film region located at the front end of the second empty film region;

[0016] The step of cutting the first insulating film on the strip membrane material includes: obtaining the distance between the first empty membrane area and the second empty membrane area along the length direction of the strip membrane material and setting it as a first distance; and cutting the first insulating film from the strip membrane material in response to the first distance being within a first preset range.

[0017] In some embodiments, a marking portion is provided on the side of the adhesive coating area facing away from the electrode assembly;

[0018] The step of cutting the first insulating film from the strip film material includes: obtaining the distance between the marking portion on the first insulating film and the first empty film area or the second empty film area along the length direction of the strip film material and setting it as a second distance; in response to the first distance being within a first preset range and the second distance being within a second preset range, cutting the first insulating film from the strip film material.

[0019] In some embodiments, after the insulating film is wound and wrapped around the outer periphery of the electrode assembly, the wrapping method further includes: performing a wrapping quality test on the insulating film and obtaining a quality test result; and, in response to the quality test result indicating that the wrapping quality of the insulating film is qualified, allowing the electrode assembly to proceed to the next process.

[0020] In some embodiments, the step of wrapping an insulating film around the outer periphery of an electrode assembly includes: attaching the starting end of the wrapping of the insulating film to the outer peripheral surface of the electrode assembly; and rotating the electrode assembly about its own axis so that the insulating film wraps around the outer periphery of the electrode assembly.

[0021] While the insulating film is rolled up and wrapped around the outer periphery of the electrode assembly, a visual image of the insulating film is acquired.

[0022] The process of inspecting the coating quality of the insulating film and obtaining the inspection results includes: inspecting the coating quality of the insulating film based on visual images and obtaining the inspection results.

[0023] In some embodiments, while the insulating film is wrapped around the outer periphery of the electrode assembly, the outer contour perimeter of the electrode assembly is also detected.

[0024] Based on visual images, the coating quality of the insulating film is inspected and the quality inspection results are obtained, including: determining the unfolded view of the insulating film based on visual images; determining the total size and the first size based on the unfolded view; wherein, in the flattened state, the size of the insulating film along the first direction is the total size, and the size of the adhesive coating area along the first direction is the first size; and determining the quality inspection results based on the total size, the first size, and the outer contour perimeter of the electrode assembly.

[0025] An embodiment of the third aspect of this application provides an apparatus for preparing a battery cell, comprising: an electrode providing assembly, a film supply assembly, and a coating assembly. The electrode providing assembly is used to provide an electrode assembly; the film supply assembly is used to provide an insulating film, wherein the insulating film includes a coating region and a blank film region, and the blank film region is connected to at least one end of the coating region along a first direction, the first direction being perpendicular to the thickness direction of the coating region; the coating assembly is used to roll the insulating film around and cover the outer periphery of the electrode assembly, wherein the coating region and the blank film region are successively wound onto the electrode assembly, and the starting end and the ending end of the winding of the insulating film along its own winding direction at least partially overlap, wherein the coating region is disposed on at least a portion of the outer periphery of the electrode assembly, and at most one of the starting end and the ending end of the winding includes a portion of the coating region.

[0026] An embodiment of the fourth aspect of this application provides a battery device that includes the battery cell described in the above embodiments.

[0027] An embodiment of the fifth aspect of this application provides an electrical device that includes the battery device described in the above embodiments, the battery device being used to provide electrical energy.

[0028] An embodiment of the sixth aspect of this application provides an energy storage device that includes the battery device described above, the battery device being capable of storing and providing electrical energy.

[0029] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0030] In the accompanying drawings, unless otherwise specified, the same reference numerals throughout the various drawings denote the same or similar parts or elements. These drawings are not necessarily drawn to scale. It should be understood that these drawings depict only some embodiments disclosed in this application and should not be construed as limiting the scope of this application.

[0031] Figure 1 This is a schematic diagram of the vehicle structure according to some embodiments of this application;

[0032] Figure 2 This is an exploded view of the battery device according to some embodiments of this application;

[0033] Figure 3 This is an exploded structural diagram of a battery cell according to some embodiments of this application;

[0034] Figures 4 to 9 This is a schematic diagram of the electrode assembly and insulating film in some embodiments of this application;

[0035] Figure 10 This is a schematic diagram of the insulating film in a flattened state according to some embodiments of this application;

[0036] Figure 11 This is a schematic flowchart of an electrode assembly coating method according to some embodiments of this application;

[0037] Figure 12 This is a schematic diagram of the structure of the insulating film core according to some embodiments of this application;

[0038] Figure 13 This is a schematic diagram of an electrode assembly coating device according to some embodiments of this application.

[0039] Explanation of reference numerals in the attached figures:

[0040] 1000 vehicles;

[0041] Battery unit 100, controller 200, motor 300;

[0042] Battery cell assembly 10, battery cell 11, housing 110, end cap 111, electrode assembly 120, positive electrode 121, negative electrode 122, insulating film 130, substrate 131, adhesive layer 132, coating area 133, marking part 1331, empty film area 134, first empty film area 134a, second empty film area 134b, housing 20, first housing 21, second housing 22, insulating film core 30, first insulating film 31, wrapping equipment 40, color detection element 41, cutting assembly 42, camera 43. Detailed Implementation

[0043] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0044] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0045] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0046] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0047] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0048] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0049] In the description of the embodiments of this application, the technical 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 only for the convenience of describing the embodiments of this application and simplifying the description, and are not intended to 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 the embodiments of this application.

[0050] In the description of the embodiments of this application, unless otherwise expressly specified and limited, the technical terms such as "installation", "connection", "linking", and "fixing" 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 connection of two components or the interaction between two components.

[0051] In this application, the term "parallel" includes not only absolute parallelism but also approximate parallelism as commonly understood in engineering; similarly, "perpendicular" also includes not only absolute perpendicularity but also approximate perpendicularity as commonly understood in engineering. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this application based on the specific circumstances.

[0052] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a specific parameter, it is expected that ranges of 60-110 and 80-120 are also included. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are listed, then the following ranges are all expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5. In this application, unless otherwise stated, the numerical range "ab" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" have been listed in this article; "0-5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0053] Unless otherwise specified, all steps in this application may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the mention that the method may also include step (c) indicates that step (c) may be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0054] Unless otherwise specified, the terms "comprising" and "including" as used in this application can be open-ended or closed-ended. For example, "comprising" and "including" can mean that other components not listed may also be included, or that only the listed components may be included.

[0055] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0056] Currently, the application of rechargeable batteries is becoming increasingly widespread, judging from market trends. They are not only used in energy storage systems for hydropower, thermal power, wind power, and solar power plants, but also extensively in various electronic devices, such as electric bicycles, electric motorcycles, and electric vehicles, as well as in military equipment and aerospace. As the application areas of rechargeable batteries continue to expand, the market demand is also constantly increasing.

[0057] In some related technologies, an insulating film (also known as a blue film) covers part of the outer periphery of the electrode assembly. In other words, there is a gap between the two ends of the insulating film along the circumference of the electrode assembly, so that part of the outer surface of the electrode assembly is not covered by the insulating film. In this method, welding slag, dust, and other particles introduced during the battery cell assembly process enter the battery cell. During battery operation, these particles may puncture the separator at the locations of the electrode assembly not covered by the insulating film, which can easily cause a short circuit and battery failure.

[0058] In some related technologies, due to unavoidable dimensional errors, positioning deviations, and differences in membrane tension during actual manufacturing, it is difficult to achieve perfect end-to-end alignment of the insulating film. Instead, a certain margin is left, resulting in partial overlap at both ends of the insulating film. In this method, the overlapping area of ​​the insulating film has two substrate layers and two adhesive layers, resulting in a relatively large thickness in the overlapping area. This causes the insulating film to bind the electrode assembly too tightly, restricting the normal expansion and contraction of the electrode assembly during battery charging and discharging, leading to structural damage to the electrode assembly and affecting the performance of the battery cells.

[0059] As described above, when the insulating film covers the electrode assembly less than one full circle, the insulation protection effect is poor; when the insulating film covers the electrode assembly more than one full circle, the degree of constraint imposed by the insulating film on the electrode assembly is too great. Therefore, existing forms of insulating film coverage struggle to achieve a balance between insulation protection and the degree of constraint.

[0060] Based on the above considerations, this application designs a battery cell by covering the entire outer periphery of the electrode assembly with an insulating film, and the insulating film includes a coating area and an empty film area, and the coating area is located on at least part of the outer periphery of the electrode assembly, and the two ends of the coating area do not overlap along the winding direction.

[0061] In such a battery cell, because the insulating film covers the entire periphery of the electrode assembly, the electrode assembly can be reliably insulated and protected by the insulating film. At the same time, since the adhesive coating areas do not overlap, the thickness of the overlapping areas of the insulating film can be reduced, thus weakening the binding force of the insulating film on the electrode assembly. In this way, while the insulating film provides insulation and protection, it does not bind the electrode assembly too tightly.

[0062] The battery cells and battery devices described in this application can be used, but are not limited to, in electrical equipment or energy storage devices such as vehicles, ships, or aircraft. A power system comprising the battery cells and battery devices described in this application can be used to construct such electrical equipment or energy storage devices.

[0063] The energy storage device utilizing a battery as a power system in this application embodiment can be used in energy storage power stations, wind power generation systems, solar power generation systems, mobile power systems, or temporary power supply systems, etc. The energy storage device can store electrical energy as needed and output it at appropriate times. For example, the energy storage device can store electrical energy during off-peak hours and provide power to relevant users or electrical equipment during peak hours. The energy storage device provided in this application embodiment can be used in any power system that requires energy storage.

[0064] In some embodiments, the energy storage device is an energy storage container, an energy storage cabinet, an energy storage power station, an energy storage battery pack, or a portable energy storage system.

[0065] In some embodiments, the energy storage device may include a cabinet and one or more battery clusters housed within the cabinet. Each battery cluster may include multiple battery units connected in series via a busbar to increase the voltage of the energy storage device. When the energy storage device includes multiple battery clusters, these clusters are connected in parallel to increase the capacity of the energy storage device.

[0066] In this application embodiment, the electrical devices using battery devices as power sources can be, but are not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric vehicles, electric cars, ships, spacecraft, etc. Among them, electric toys can include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc., and spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.

[0067] It should be understood that the technical solutions described in the embodiments of this application are not limited to the battery devices and electrical equipment described above, but can also be applied to all battery devices including housings and electrical equipment using battery devices. However, for the sake of brevity, the following embodiments are all illustrated using electric vehicles as examples.

[0068] 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 device 100 is provided inside the vehicle 1000, and the battery device 100 can be located at the bottom, front, or rear of the vehicle 1000. The battery device 100 can be used to power the vehicle 1000; for example, the battery device 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 device 100 to supply power to the motor 300, for example, to meet the power needs of the vehicle 1000 during starting, navigation, and driving.

[0069] In some embodiments of this application, the battery device 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.

[0070] Figure 2 A schematic diagram of the structure of a battery device 100 according to an embodiment of this application is shown. Figure 2 As shown, the battery device 100 mentioned in the embodiments of this application may include one or more battery cell assemblies 10 for providing voltage and capacity. The battery cell assembly 10 may include multiple battery cells 11, which are connected in series, parallel, or mixed connection via a busbar.

[0071] In some embodiments, the battery cell assembly 10 is typically formed by arranging a plurality of battery cells 11.

[0072] As an example, the battery cell assembly 10 can be a battery module, which is formed by arranging and fixing multiple battery cells 11 together to form an independent module. As an example, the battery module can be formed by bundling multiple battery cells 11 together with cable ties.

[0073] In some embodiments, such as Figure 2As shown, the battery device 100 can be a battery pack, which includes a housing 20 and one or more individual battery cells 10, with the individual battery cells 10 housed within the housing 20. The housing 20 can be a simple three-dimensional structure such as a single cuboid, cylinder, or sphere, or a complex three-dimensional structure composed of combinations of simple cuboids, cylinders, or spheres. The material of the housing 20 can be an alloy such as aluminum alloy or iron alloy, a polymer such as polycarbonate or polyisocyanurate foam, or a composite material such as glass fiber and epoxy resin.

[0074] As an example, the battery cell assembly 10 can be a battery module, and the battery cell assembly 10 can be housed in the housing 20 by fixing the battery module in the housing 20.

[0075] As an example, the battery cell assembly 10 can also be housed in the housing 20 by directly fixing multiple battery cells 11 to the housing 20.

[0076] As an example, the housing 20 may include a first housing 21 and a second housing 22. The first housing 21 and the second housing 22 are fastened together to form a closed space inside the housing 20 to house the battery cell assembly 10. Here, "closed" refers to covering or closing, and can be either non-sealed or sealed to prevent liquids or other foreign objects from affecting the charging or discharging of the battery cell 11. The first housing 21 may be a top cover or a bottom plate.

[0077] As an example, the housing 20 may include a top cover, a frame, and a bottom plate. The top cover and the bottom plate are respectively connected to the frame, so that the interior of the housing 20 forms an enclosed space to accommodate the battery cell assembly 10.

[0078] In some embodiments, the housing 20 may be part of the vehicle's chassis structure. For example, a portion of the housing 20 may be at least a portion of the vehicle's floor, or a portion of the housing 20 may be at least a portion of the vehicle's crossbeams and longitudinal beams.

[0079] The battery cell 11 provided in the embodiments of this application can be a secondary battery. A secondary battery refers to a battery cell 11 that can be used again after being discharged by recharging to activate the active material.

[0080] The battery cell 11 can be a lithium-ion battery, sodium-ion battery, sodium-lithium-ion battery, lithium metal battery, sodium metal battery, lithium-sulfur battery, magnesium-ion battery, nickel-metal hydride battery, nickel-cadmium battery, lead-acid battery, etc., and this application embodiment is not limited to this. As an example, the battery cell 11 can be a cylindrical battery cell, a prismatic battery cell, or a battery cell 11 of other shapes. Prismatic battery cells include prismatic battery cells, blade-shaped battery cells, and multi-prismatic battery cells, such as hexagonal prismatic battery cells, etc., and this application has no particular limitation.

[0081] Figure 3 An exploded structural diagram of a battery cell according to some embodiments of this application is shown. For example... Figure 3 As shown, the battery cell 11 provided in the embodiments of this application includes a casing, an electrode assembly 120, and an electrolyte. The electrode assembly 120 is a component in the battery cell 11 where an electrochemical reaction occurs. The electrode assembly 120 and the electrolyte are housed within the casing. As an example, the electrolyte may be liquid, gel-like, or solid.

[0082] As an example, the outer casing can be a steel casing, an aluminum casing, a plastic casing (such as polypropylene), a composite metal casing (such as a copper-aluminum composite casing 110), or an aluminum-plastic film, etc. In some embodiments, the outer casing can be a sealed structure or a non-sealed structure. As an example, when the outer casing is a non-sealed structure, the outer casing serves to protect the electrode assembly 120, and a sealing bag is also included between the outer casing and the electrode assembly 120. The sealing bag is used to encapsulate the electrode assembly 120 and the electrolyte. Specifically, the sealing bag can be a bag-shaped insulating component or an aluminum-plastic film. When the outer casing is a sealed structure, it is used to encapsulate the electrode assembly 120 and the electrolyte, etc.

[0083] As an example, the housing includes a housing 110 and an end cap 111. The housing 110 has an opening, and the end cap 111 closes to the opening of the housing 110. The housing 110 and the end cap 111 together enclose a mounting cavity, which provides mounting space for components such as the electrode assembly 120.

[0084] End cap 111 refers to a component that covers the opening of housing 110 to isolate the internal environment of the battery cell from the external environment. The shape of end cap 111 can be adapted to the shape of housing 110 to fit it. Optionally, end cap 111 can be made of a material with a certain hardness and strength (such as aluminum alloy), so that end cap 111 is not easily deformed under pressure or impact, giving the battery cell higher structural strength and improving safety performance. Functional components such as electrode terminals can be provided on end cap 111. Electrode terminals can be used for electrical connection with electrode assembly 120 to output or input electrical energy to the battery cell.

[0085] The housing 110 is a component used to cooperate with the end cap 111 to form the internal environment of the battery cell, wherein the formed internal environment can accommodate the electrode assembly 120, electrolyte, and other components. The housing 110 and the end cap 111 can be independent components. The housing 110 has an opening, and the end cap 111 closes the opening to form the internal environment of the battery cell. Alternatively, the end cap 111 and the housing 110 can be integrated. Specifically, the end cap 111 and the housing 110 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 110, the end cap 111 closes the housing 110. The housing 110 can be of various shapes and sizes, such as cuboid, cylindrical, hexagonal prism, etc. Specifically, the shape of the housing 110 can be determined according to the specific shape and size of the electrode assembly 120. The material of the housing 110 can be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and this application embodiment does not impose any special limitations on this.

[0086] The housing 110 may be open at one end or open at both ends. In some examples, the housing 110 may be a structure with an opening on one side, with one end cap 111 covering the housing 110. In other examples, the housing 110 may be a structure with openings on both sides, with two end caps 111 covering the two openings of the housing 110 respectively.

[0087] Figures 4 to 9 This is a schematic diagram of the electrode assembly 120 and the insulating film 130 according to some embodiments of this application. Please refer to... Figures 4 to 9 The battery cell 11 also includes an insulating film 130, which is wound around the outer periphery of the electrode assembly 120. The insulating film 130 has a winding start end and a winding end along its winding direction, and the winding start end and the winding end at least partially overlap. The insulating film 130 includes a coating area 133 and an empty film area 134. At least one end of the coating area 133 along the winding direction is connected to the empty film area 134. The coating area 133 is disposed on at least a portion of the outer periphery of the electrode assembly 120, and at most one of the winding start end and the winding end includes the coating area 133.

[0088] Electrode assembly 120 is the component in the battery cell 11 where electrochemical reactions occur. Electrode assembly 120 includes a positive electrode 121, a negative electrode 122, and a separator. During the charging and discharging process of the battery cell 11, active ions (e.g., lithium ions) repeatedly insert and extract between the positive electrode 121 and the negative electrode 122. The separator, located between the positive and negative electrode 121, prevents short circuits between the positive and negative electrodes while allowing active ions to pass through.

[0089] The electrode assembly 120 can be a wound structure, a stacked structure, or a hybrid structure of wound and stacked. In some embodiments, the electrode assembly 120 can be cylindrical, flat, or polygonal.

[0090] In some embodiments, the electrode assembly 120 can be a wound structure. As an example, the positive electrode 121, the separator, and the negative electrode 122 are wound into a cylindrical electrode assembly 120. As an example, the positive electrode 121, the separator, and the negative electrode 122 are wound into a cylindrical wound structure and then flattened to obtain a flat electrode assembly 120.

[0091] In some embodiments, the electrode assembly 120 has a stacked structure. As an example, multiple positive electrode plates 121 and multiple negative electrode plates 122 can be provided, with the multiple positive electrode plates 121 and multiple negative electrode plates 122 alternately stacked. As an example, multiple positive electrode plates 121 can be provided, and the negative electrode plates 122 can be folded to form multiple stacked folded segments, with a positive electrode plate 121 sandwiched between adjacent folded segments. As an example, both the positive electrode plate 121 and the negative electrode plate 122 can be folded to form multiple stacked folded segments.

[0092] As an example, multiple separators can be provided, each disposed between any adjacent positive electrode 121 or negative electrode 122.

[0093] As an example, the separator can be continuously arranged between any adjacent positive electrode 121 or negative electrode 122 by folding or rolling.

[0094] An insulating film 130 covers the outer peripheral surface of the electrode assembly 120, serving to insulate and isolate the electrode assembly 120 from the housing 110, thus providing insulation and protection. The insulating film 130 being rolled around the outer periphery of the electrode assembly 120 means that the insulating film 130 is disposed around the outer periphery of the electrode assembly 120 and extends beyond one turn, covering the entire outer peripheral surface of the electrode assembly 120. For example, when the electrode assembly 120 has a rolled structure, the outer peripheral surface of the electrode assembly 120 is parallel to the axial direction of the electrode assembly 120 (see the Z direction). For example, when the electrode assembly 120 has a stacked structure, the outer peripheral surface of the electrode assembly 120 is parallel to the height direction of the electrode assembly 120, and the height direction of the electrode assembly 120, the thickness direction of the positive electrode 121, and the width direction of the positive electrode 121 are all perpendicular to each other.

[0095] In some examples, when the electrode assembly 120 is a wound structure, the winding direction of the insulating film 130 is perpendicular to the axial direction of the electrode assembly 120. For example, the electrode assembly 120 has a cylindrical wound structure, and the winding direction of the insulating film 130 can be either clockwise or counterclockwise. Figure 4 and Figure 9In the diagram, the winding direction of the insulating film 130 can be referenced to the R direction.

[0096] When the insulating film 130 is wound along its own winding direction to cover the electrode assembly 120, the starting end of the winding serves as the starting point of the winding of the insulating film 130 and first contacts the electrode assembly 120. When the insulating film 130 is wound along its own winding direction to cover the electrode assembly 120, the ending end of the winding serves as the ending point of the winding of the insulating film 130. The starting end of the winding is closer to the center of the electrode assembly 120 than the ending end of the winding.

[0097] In its flattened state, the insulating film 130 includes a substrate 131 and an adhesive layer 132 stacked along its thickness direction. The adhesive layer 132 is disposed on the portion of the substrate 131 facing the electrode assembly 120. The flattened state refers to the state where the insulating film 130, rolled and covering the electrode assembly 120, is unfolded to form a flat or near-flat surface. The substrate 131 can be made of at least one of polyester film (PET), polyimide film (PI), polypropylene film (PP), and polyethylene film (PE). The adhesive layer 132 can be made of any one of pressure-sensitive adhesive (e.g., styrene-butadiene rubber), epoxy adhesive, etc. The substrate 131 can be a transparent substrate, a white substrate, a yellow substrate, a red substrate, or a green substrate; of course, in some embodiments, the substrate 131 can also be other colors. The adhesive layer 132 can be any one of transparent, white, light yellow, light brown, etc. The colors of the substrate 131 and the adhesive layer 132 can be the same or different.

[0098] This application does not specifically limit the thickness of the substrate 131 and the adhesive layer 132. Exemplarily, the ratio of the thickness of the adhesive layer 132 to the thickness of the substrate 131 can be 1:2 to 1:10, for example, a range consisting of 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, or any combination thereof. As an example, the thickness of the adhesive layer 132 can be 10µm, and the thickness of the substrate 131 can be 40µm.

[0099] It is understood that the portion of the insulating film 130 without the adhesive layer 132 forms an empty film area 134, and the portion of the insulating film 130 with the adhesive layer 132 forms an adhesive application area 133. In some embodiments, such as Figure 4 and Figure 5 As shown, one end of the adhesive coating area 133 along the winding direction is connected to an empty film area 134, that is, the insulating film 130 is provided with an empty film area 134. In some embodiments, such as Figures 6 to 9 As shown, the adhesive coating area 133 is connected to two empty film areas 134 at both ends along the winding direction, that is, the insulating film 130 is provided with two empty film areas 134.

[0100] The adhesive coating area 133 is located on at least a portion of the outer periphery of the electrode assembly 120, meaning that the adhesive coating area 133 covers the outer periphery of the electrode assembly 120 in less than one circle or exactly one circle.

[0101] The fact that at most one of the winding start end and the winding end includes a portion of the adhesive coating area 133 means that either the winding start end or the winding end includes a portion of the adhesive coating area 133, or neither the winding start end nor the winding end includes a portion of the adhesive coating area 133. In other words, the winding start end and the winding end will not simultaneously include the adhesive coating area 133, so that the two ends of the adhesive coating area 133 do not overlap along the winding direction.

[0102] In this embodiment, the battery cell 11 is designed to have an insulating film 130 wound around and covered on the outer periphery of the electrode assembly 120, ensuring reliable insulation protection of the electrode assembly 120 by the insulating film 130. Simultaneously, the insulating film 130 is designed to include an adhesive coating area 133 and an empty film area 134. The adhesive coating area 133 is disposed on at least a portion of the outer periphery of the electrode assembly 120. The starting and ending ends of the winding of the insulating film 130 overlap, and at most one of the starting and ending ends includes a portion of the adhesive coating area 133. Thus, the adhesive coating areas 133 do not overlap along the winding direction. Consequently, the adhesive layer 132 in the overlapping area of ​​the insulating film 130 is at most one layer. Therefore, compared to the technical solution where the insulating film 130 covers exactly one circumference of the outer periphery of the electrode assembly 120, this embodiment eliminates one or two adhesive layers 132 in the overlapping area of ​​the insulating film 130. Without changing the thickness of the substrate 131 and the adhesive layer 132, the thickness of the overlapping area of ​​the insulating film 130 is reduced, thereby lessening the constraint of the overlapping area of ​​the insulating film 130 on the electrode assembly 120. Thus, in the technical solution of this embodiment, a good balance is achieved between the insulating and protective effect of the insulating film 130 on the electrode assembly 120 and the degree of constraint imposed by the insulating film 130 on the electrode assembly 120.

[0103] In addition, compared with the technical solution where the insulating film 130 covers the outer periphery of the electrode assembly 120 in exactly one circle, in this embodiment, since the starting end and the ending end of the winding of the insulating film 130 overlap, the process error tolerance of the electrode assembly 120 during the coating process is higher.

[0104] As described above, one end of the adhesive coating area 133 along the winding direction is connected to the empty film area 134, or both ends of the adhesive coating area 133 along the winding direction are each connected to the empty film area 134.

[0105] In some embodiments, such as Figure 4 and Figure 5As shown, one end of the adhesive coating area 133 along the winding direction is connected to an empty film area 134, that is, the insulating film 130 is provided with an empty film area 134. For example, as... Figure 4 As shown, the winding start end is formed by a partial adhesive coating area 133, and the winding end end is formed by an empty film area 134. Specifically, the winding end end can be a partial empty film area 134 or the entire empty film area 134. For example, as... Figure 5 As shown, the winding start end is formed by the empty film region 134, and the winding end end is formed by the partially coated adhesive region 133. In this example, the overlapping area of ​​the insulating film 130 has two substrate layers 131 and one adhesive layer 132.

[0106] According to some embodiments of this application, the insulating film 130 includes two empty film regions 134, which correspond one-to-one with and are connected to the two ends of the adhesive coating region 133 along the winding direction. In this embodiment, both the winding start end and the winding end include empty film regions 134. For example, the winding start end may be formed by empty film regions 134, or the winding start end may be formed by empty film regions 134 and a portion of the adhesive coating region 133. For example, the winding end may be formed by empty film regions 134, or the winding end may be formed by empty film regions 134 and a portion of the adhesive coating region 133.

[0107] Without changing the size of the adhesive coating area 133 and the empty film area 134, the insulating film 130 in this embodiment has a larger allowance so as to reliably cover the entire outer periphery of the electrode assembly 120.

[0108] In some embodiments, such as Figure 8 and Figure 9 As shown, the winding start end is formed by one of the two empty film regions 134 closer to the center of the electrode assembly 120 and a portion of the adhesive coating region 133.

[0109] According to some embodiments of this application, such as Figure 6 and Figure 7 As shown, the winding start end is formed by the one of the two empty film regions 134 closer to the center of the electrode assembly 120. In other words, the winding start end only includes the empty film region 134. The winding start end can be a portion of the empty film region 134 or the entire empty film region 134.

[0110] Compared with the technical solution that includes an empty film area 134 and a partial adhesive coating area 133 at the winding start end, in this embodiment, without changing the size of the insulating film 130, since the winding start end only includes an empty film area 134, the portion of the adhesive coating area 133 near the empty film area 134 does not overlap with the winding end end along the winding direction. This results in less of the overlapping area of ​​the insulating film 130 having an adhesive layer 132, thus reducing the thickness of more of the overlapping area of ​​the insulating film 130, which is beneficial to further weaken the binding degree of the insulating film 130 on the electrode assembly 120.

[0111] In some embodiments, such as Figure 6 and Figure 8 As shown, the winding termination can be formed from the one of the two empty film regions 134 further away from the center of the electrode assembly 120. In other words, the winding termination only includes the empty film region 134. The winding termination can be a portion of the empty film region 134 or the entire empty film region 134. Figure 6 In the process, the overlapping area of ​​the insulating film 130 has only two substrate layers 131. Figure 8 In the process, the overlapping area of ​​the insulating film 130 has two substrate layers 131 and one adhesive layer 132, while the remaining part has only two substrate layers 131.

[0112] According to some embodiments of this application, such as Figure 5 , Figure 7 and Figure 9 As shown, the winding end includes the portion of the adhesive coating area 133.

[0113] As an example, such as Figure 5 As shown, the insulating film 130 has an empty film region 134, which serves as the starting end of winding. As an example, such as... Figure 7 and Figure 9 As shown, each end of the adhesive coating area 133 along the winding direction is connected to an empty film area 134, and the winding termination is formed by the one of the two empty film areas 134 further away from the center of the electrode assembly 120 and a portion of the adhesive coating area 133. In this example, the overlapping area of ​​the insulating film 130 has two substrate layers 131 and one adhesive layer 132, while the remaining portion has only two substrate layers 131.

[0114] Compared with the technical solution where the winding end is formed only by the empty film area 134, this embodiment designs the winding end to include the adhesive area 133, so that the winding end is bonded to the outside of the winding start end. This makes it easier for the overlapping parts of the insulating film 130 to not loosen, and improves the winding tightness of the insulating film 130. This helps to reduce the difficulty caused by the loosening of the insulating film 130 in the process of transferring the electrode assembly 120 covered with the insulating film 130 to subsequent processes.

[0115] According to some embodiments of this application, the dimension of the coating area 133 along the winding direction is a first dimension, and the perimeter C of the outer contour of the electrode assembly 120 is a second dimension, with the first dimension being 80% to 99% of the second dimension.

[0116] Understandably, in its flattened state, the insulating film 130 includes an adhesive coating area 133 and an empty film area 134, which are connected along a first direction. At least one end of the adhesive coating area 133 along the first direction is connected to the empty film area 134. The first direction can be referred to as the X direction. Figure 10As shown, when the insulating film 130 is in a flattened state, the dimension L1 of the adhesive coating area 133 along the first direction is equal to the first dimension.

[0117] The perimeter of the outer contour of the electrode assembly 120 can be understood as the perimeter of the cross-section of the electrode assembly 120, where the cross-section refers to the section perpendicular to the central axis of the electrode assembly 120, or it can be understood as the total length of the outer boundary line of the electrode assembly 120. L1 / C×100% can be a range of 80%, 82%, 85%, 88%, 90%, 92%, 95%, 97%, 99%, or any combination of two of these.

[0118] In this embodiment, the ratio of the first dimension to the second dimension is within the aforementioned range. This allows for a larger area of ​​the adhesive coating region 133, resulting in a stronger bond between the insulating film 130 and the electrode assembly 120, thus improving the reliability of the insulating film 130's coverage of the electrode assembly 120. Furthermore, this also allows for a smaller ratio of the empty film region 134 along the winding direction to the total size of the insulating film 130 along the winding direction, reducing the likelihood of wrinkles appearing in the insulating film 130 due to displacement of the empty film region 134.

[0119] According to some embodiments of this application, the sum of the dimensions of all empty membrane regions 134 along the winding direction is the third dimension, and the ratio of the third dimension to the first dimension is 1:4 to 1:50.

[0120] It is understandable that when the insulating film 130 is in a flattened state, the dimension W of the empty film region 134 along the first direction is equal to the dimension of the empty film region 134 along the winding direction. The dimension of the insulating film 130 in the flattened state along the first direction is the total dimension L. 总 Overall dimensions L 总 - First dimension L1 = Third dimension.

[0121] The ratio of the third dimension to the first dimension can be a range of 1:4, 1:10, 1:15, 1:20, 1:25, 1:30, 1:35, 1:40, 1:45, 1:50, or any two of these. For example, the dimension W of the empty membrane region 134 along the first direction can be 5 mm, and the first dimension can be 150 mm.

[0122] This embodiment ensures that the ratio of the third dimension to the first dimension is within the aforementioned range, preventing the size of the empty film region 134 along the winding direction from being too large or too small. This facilitates the overlap of the insulating film 130 with a reasonable allowance. Consequently, during the process of wrapping the insulating film 130 around the electrode assembly 120, it is easy to accurately overlap the winding start end and the winding end.

[0123] The second aspect of this application provides a method for coating an electrode assembly 120. After coating the electrode assembly 120 using this method, it can be used to prepare any of the aforementioned battery cells 11. Specifically, the coating method of this embodiment can be performed after the electrode assembly 120 manufacturing process and before the electrode assembly 120 casing process. For example, the coating method of this embodiment can be implemented by a coating machine. Figure 11 For a schematic diagram of the fabrication process of the battery cell 11 in some embodiments of this application, please refer to [link / reference]. Figure 11 The coating method for electrode assembly 120 includes the following steps.

[0124] S110 provides electrode assembly 120.

[0125] S120, providing an insulating film 130, wherein the insulating film 130 includes an adhesive coating area 133 and an empty film area 134, at least one end of the adhesive coating area 133 is connected to the empty film area 134 along a first direction, the first direction being perpendicular to the thickness direction of the adhesive coating area 133.

[0126] S130, the insulating film 130 is wound and wrapped around the outer periphery of the electrode assembly 120. The adhesive coating area 133 and the empty film area 134 are successively wound onto the electrode assembly 120, and the starting end and the ending end of the winding of the insulating film 130 along its own winding direction at least partially overlap. The adhesive coating area 133 is disposed on at least part of the outer periphery of the electrode assembly 120, and at most one of the starting end and the ending end includes a portion of the adhesive coating area 133.

[0127] In S110, the electrode assembly 120 can be either a wound structure or a stacked structure. For example, if the electrode assembly 120 is a wound structure, it can be obtained through a winding process. If the electrode assembly 120 is a stacked structure, it can be obtained through a stacking process.

[0128] S120 can be implemented by a film supply assembly. Providing the insulating film 130 in S120 means providing an insulating film 130 in a flattened state. A flattened state refers to unfolding the insulating film 130, which is rolled up to cover the electrode assembly 120, to form a flat or near-flat surface. The first direction and the second direction are perpendicular to the thickness direction of the adhesive coating area 133. When the insulating film 130 covers the electrode assembly 120, the second direction is parallel to the axial direction of the electrode assembly 120 (the height direction of the electrode assembly 120).

[0129] S130 can be achieved by a covering assembly. In S130, the adhesive coating area 133 and the empty film area 134 are wound onto the electrode assembly 120 in sequence, meaning that the adhesive coating area 133 and the empty film area 134 are wound onto the electrode assembly 120 in a sequential order. Thus, when the insulating film 130 covers the electrode assembly 120, the adhesive coating area 133 and the empty film area 134 are connected sequentially along the winding direction of the insulating film 130.

[0130] By employing the coating method of this embodiment, the outer peripheral surface of the electrode assembly 120 can be covered by the insulating film 130, ensuring reliable insulation protection of the electrode assembly 120 by the insulating film 130. Furthermore, since the adhesive application areas 133 do not overlap along the winding direction, the adhesive layer 132 in the overlapping area of ​​the insulating film 130 is at most one layer. Thus, without changing the thickness of the substrate 131 and the adhesive layer 132, the thickness of the overlapping area of ​​the insulating film 130 is reduced, thereby lessening the constraint of the overlapping area of ​​the insulating film 130 on the electrode assembly 120. Therefore, in the technical solution of this embodiment, a good balance is achieved between the insulation protection effect of the insulating film 130 on the electrode assembly 120 and the degree of constraint of the insulating film 130 on the electrode assembly 120.

[0131] According to some embodiments of this application, the specific implementation process of step S120 above may include the following steps S121 to S123.

[0132] S121, an insulating film core 30 is provided, wherein the insulating film core 30 includes a plurality of insulating films 130 connected sequentially along the length direction of the insulating film core 30, the insulating film 130 includes an adhesive coating area 133 and an empty film area 134, and at least one end of the adhesive coating area 133 along the length direction of the insulating film core 30 is connected to the empty film area 134.

[0133] S122, unwind the insulating film core 30 into a strip film.

[0134] S123, the first insulating film 31 on the strip film is cut from the strip film, wherein, along the tape path of the strip film, the first insulating film 31 is the insulating film 130 at the very front end of the strip film.

[0135] Insulating film core 30 can be referred to Figure 12 As shown, the structures of the multiple insulating films 130 on the insulating film core 30 can be identical. As an example, each insulating film 130 may include an empty film area 134, which may be released before or after the adhesive-coated area 133 in the same insulating film 130 during unwinding. Figure 12 As shown, each insulating film 130 may include two empty film areas 134, and the two empty film areas 134 are respectively connected to the two ends of the adhesive coating area 133 along the length direction of the insulating film core 30.

[0136] In S122, the insulating film core 30 rotates around its own axis to unwind, and the released portion of the insulating film core 30 is the strip film material. The strip film material is conveyed to gradually approach the covering component in preparation for S130.

[0137] S123 is specifically implemented by the cutting assembly 42, which can be a laser cutting head, a ceramic cutter, a metal cutter, or a wire cutting assembly. It should be understood that the dimension of the released portion of the insulating film core 30 along the length of the insulating film core 30 is greater than the dimension L of an insulating film 130 along the first direction. 总 The front end of the strip membrane can be understood as the end along its own running path, the end of the strip membrane furthest from the insulating film core 30, and also the end closest to the covering component.

[0138] In this embodiment, step S130 specifically involves wrapping the first insulating film 31 around the entire outer periphery of the electrode assembly 120.

[0139] In this embodiment, the leading edge of the strip of film released from the insulating film core 30 is cut from the strip of film and then wound around the outer periphery of the electrode assembly 120. Subsequently, the insulating film core 30 continues to be released, and the strip of film continues to be conveyed to the covering assembly. An insulating film 130 adjacent to the first insulating film 31 (which may be referred to as the second insulating film 130) is conveyed forward and becomes a new first insulating film 31. In this way, each insulating film 130 on the insulating film core 30 is cut sequentially.

[0140] According to some embodiments of this application, such as Figure 12 As shown, the first insulating film 31 includes two empty film regions 134, namely a first empty film region 134a and a second empty film region 134b. The first empty film region 134a is located at the front end of the second empty film region 134b. In other words, the first empty film region 134a is located upstream of the second empty film region 134b.

[0141] Furthermore, the above step S123 can be implemented using the following steps.

[0142] S210, obtain the distance between the first empty membrane region 134a and the second empty membrane region 134b along the length direction of the strip membrane material and set it as the first distance.

[0143] S220, in response to the first distance being within a first preset range, the first insulating film 31 is cut from the strip film material.

[0144] There are various ways to implement S210. In some embodiments, the substrate 131 and the adhesive layer 132 are different colors, therefore, the adhesive coating area 133 and the empty film area 134 are also different colors. For example, if the substrate 131 is a transparent substrate and the adhesive layer 132 is blue, then the adhesive coating area 133 will be blue and the empty film area 134 will be transparent. In this example, as... Figure 13As shown, a color detection element 41 (e.g., a color mark sensor) and a cutting assembly 42 can be sequentially arranged along the belt path of the strip membrane material. The color detection element 41 is used to detect the color of the strip membrane material. In response to the color detected by the color detection element 41 being the color of the empty membrane region 134, indicating that a first empty membrane region 134a has been detected, a measurement start signal is issued, which triggers the start of the measuring device. In response to the color detected by the color detection element 41 again being the color of the empty membrane region 134, indicating that a second empty membrane region 134b has been detected, a measurement stop signal is issued, which triggers the stop of the measuring device. A first distance can be determined based on the measurement value of the measuring device. Exemplarily, the measuring device can be an encoder, etc., used to detect the belt travel distance of the strip membrane material from the issuance of the measurement start signal to the issuance of the measurement stop signal, which is the first distance.

[0145] In some embodiments, the color detection element 41 can be replaced with an image acquisition element, such as a CCD (Charge Coupled Device), CMOS (Complementary Metal Oxide Semiconductor), infrared image sensor, etc. In this example, the image acquisition element is used to acquire an image of the strip membrane material and determine a first distance based on the image of the strip membrane material.

[0146] In S220, when the first distance is within the first preset range, the size of the insulating film 130 along the winding direction is such that the insulating film 130 is sufficient to wrap around and cover the outer periphery of the electrode assembly 120, and the starting end and ending end of the winding of the insulating film 130 along its own winding direction overlap. As can be understood from the preceding text, the lower limit of the first preset range is greater than the perimeter of the outer contour of the electrode assembly 120.

[0147] In some examples, the distance between the color detection element 41 and the cutting assembly 42 along the length of the strip film is a fixed distance. In S220, in response to the first distance being within a first preset range, the cutting assembly 42 can be controlled to cut the strip film when the measuring device detects that the travel distance of the strip film is within the fixed distance. It can be understood that in this example, when the first distance is determined to be within the first preset range based on the detection result of the color detection element 41, the color detection element 41 is aligned with the second empty film area 134b. Thus, after the strip film is transmitted forward a fixed distance, the second empty film area 134b moves to be aligned with the cutting assembly 42, thereby accurately cutting the second empty film area 134b of the first insulating film 31 and the first empty film area 134a of the second insulating film 130 apart.

[0148] In this embodiment, when the distance between the first empty membrane region 134a and the second empty membrane region 134b along the length of the strip membrane material is detected to be within a certain range, the first insulating film 31 is cut from the strip membrane material. This allows the cut first insulating film 31 to cover the outer periphery of the electrode assembly 120, ensuring reliable insulation protection of the electrode assembly 120 by the insulating film 130 after covering. Moreover, compared with the technical solution where the condition for cutting the first insulating film 31 is "the first distance equals a fixed value", in this embodiment, the condition for cutting the first insulating film 31 is that the first distance is within a first preset range. That is, a process-allowed redundancy range is designed for the first distance, which helps to improve the fault tolerance of the electrode assembly 120 covering process.

[0149] According to some embodiments of this application, a marking portion 1331 is provided on the side of the coating area 133 facing away from the electrode assembly 120. Furthermore, the above step S220 can be implemented using the following steps.

[0150] S221, obtain the distance between the marking portion 1331 on the first insulating film 31 and the first empty film area 134a or the second empty film area 134b along the length direction of the strip film material and set it as the second distance.

[0151] S222, in response to the first distance being within a first preset range and the second distance being within a second preset range, the first insulating film 31 is cut from the strip film material.

[0152] When the insulating film 130 is flattened, a marking portion 1331 is located on the surface of the substrate 131 facing away from the adhesive layer 132, along the thickness direction of the insulating film 130. The marking portion 1331 can be, for example, a label attached to the substrate 131 and corresponding to the adhesive layer 132. The marking portion 1331 can be, but is not limited to, circular, rectangular, elliptical, or elongated shapes. When the insulating film 130 covers the outer periphery of the electrode assembly 120, the marking portion 1331 is located on the outer surface of the insulating film 130.

[0153] In S221, the distance between the marking portion 1331 on the first insulating film 31 and the first empty film area 134a can be obtained, as can the distance between the marking portion 1331 on the first insulating film 31 and the second empty film area 134b. The distance between the marking portion 1331 on the first insulating film 31 and the first empty film area 134a can refer to the distance between any point on the marking portion 1331 and the edge of the first empty film area 134a away from the adhesive coating area 133 along the length direction of the strip film material. Here, any point on the marking portion 1331 is not limited to the center of the marking portion 1331, the endpoint of the side of the marking portion 1331 facing the first empty film area 134a, or the endpoint of the side of the marking portion 1331 away from the first empty film area 134a.

[0154] It is understood that when the second distance is within the second preset range, in the flattened state, the marking portion 1331 is located at the center of the insulating film 130 along the first direction. As an example, the second distance is the distance between the center of the marking portion 1331 and the first empty film area 134a along the length of the strip film material; the second preset range can be, for example, [-a+L]. 总 / 2, a+L 总 [ / 2], where a is a constant. As an example, the marking portion 1331 is square, with a side length of b. The second distance is the distance between the endpoint of the marking portion 1331 facing the first empty membrane region 134a and the distance along the length of the strip membrane material of the first empty membrane region 134a. The second preset range can be, for example, [-a-b+L]. 总 / 2, a-b+L 总 [ / 2], where b is a constant.

[0155] By introducing the marking section 1331, after the insulating film 130 is wrapped around the electrode assembly 120, the information of the electrode assembly 120 can be easily traced by identifying the marking section 1331 during the transfer of the electrode assembly 120 to the subsequent process. This also helps to facilitate sorting and storage in the subsequent process.

[0156] Furthermore, in this embodiment, the conditions for cutting the first insulating film 31 are that the first distance is within the first preset range and the second distance is within the second preset range. This helps to ensure that after the cut insulating film 130 is wrapped around the electrode assembly 120, the marking part 1331 is located in the middle of the insulating film 130. This makes it easier for the identification device located in a fixed position in subsequent processes to capture and identify the marking part 1331, which helps to improve the stability of the battery production line.

[0157] It is understood that the distance between the marking portion 1331 on the first insulating film 31 and the marking portion 1331 on the second insulating film 130 along the length direction of the strip film is equal to the first distance. In some embodiments, S210 can be replaced by obtaining the distance between the marking portion 1331 on the first insulating film 31 and the marking portion 1331 on the second insulating film 130 along the length direction of the strip film and setting it as the first distance.

[0158] According to some embodiments of this application, after S130, the coating method may further include the following steps.

[0159] S310, the coating quality of the insulating film 130 is inspected and the quality inspection results are obtained.

[0160] S320, in response to the quality inspection results indicating that the coating quality of the insulating film 130 is qualified, the electrode assembly 120 is transferred to the next process.

[0161] In S310, the coating quality includes at least the coating integrity and the overlap state of the adhesive coating area 133; that is, at least the coating integrity and the overlap state of the adhesive coating area 133 are tested. It can be understood that the quality test result includes at least the following: when the coating integrity is qualified and the overlap state of the adhesive coating area 133 is qualified, the coating quality of the insulating film 130 is qualified. This indicates that the insulating film 130 covers the outer periphery of the electrode assembly 120, the starting end and the ending end of the winding of the insulating film 130 along its own winding direction at least partially overlap, and the adhesive coating area 133 is disposed on at least a portion of the outer periphery of the electrode assembly 120, with the two ends of the adhesive coating area 133 not overlapping along the winding direction. This ensures that the insulating film 130, after coating, does not bind the electrode assembly 120 too tightly.

[0162] In some embodiments, after S310, the coating method may further include step S330.

[0163] S330, in response to a quality inspection result of non-compliance, issues a prompt message indicating that the coating quality is unqualified. The staff can then adjust the coating equipment 40 according to the prompt message.

[0164] This embodiment allows for the detection of coating quality of the insulating film 130 after it is wrapped around the electrode assembly 120. This enables timely detection and correction of coating defects, which helps to improve the yield of the manufactured battery cell 11.

[0165] According to some embodiments of this application, step S130 may specifically include the following steps.

[0166] S131, attach the starting end of the winding of the insulating film 130 to the outer peripheral surface of the electrode assembly 120.

[0167] S132, causing the electrode assembly 120 to rotate around its own axis, so that the insulating film 130 is rolled up and covered around the outer periphery of the electrode assembly 120.

[0168] When step S130 is executed, step S140 can also be executed simultaneously. S140: Acquire visual images of the insulating film 130.

[0169] Furthermore, in this embodiment, the specific implementation process of step S310 can be as follows:

[0170] The coating quality of the insulating film 130 is inspected based on visual images, and the quality inspection results are obtained.

[0171] Specifically, in S131, the starting end of the winding of the first insulating film 31 is attached to the outer peripheral surface of the electrode assembly 120. It can be understood that the starting end of the winding of the first insulating film 31 refers to the end of the first insulating film 31 furthest from the insulating film core 30 along the conveyor belt path. The starting end of the winding of the first insulating film 31 can also refer to the end of the first empty film region 134a of the first insulating film 31 that faces away from the second empty film region 134b of the first insulating film 31.

[0172] In this embodiment, the electrode assembly 120 can be a cylindrical wound structure. In S132, as the electrode assembly 120 rotates, the first empty film region 134a, the adhesive coating region 133, and the second empty film region 134b are sequentially wound onto the electrode assembly 120. The number of rotations of the electrode assembly 120 is greater than 1 turn and less than 2 turns, such that the starting end and the ending end of the winding of the insulating film 130 covering the electrode assembly 120 overlap.

[0173] S140 can be implemented by camera 43, which is located outside electrode assembly 120. The camera of camera 43 faces the outer peripheral surface of electrode assembly 120 and can be aligned with the starting end of the winding of insulating film 130. As electrode assembly 120 rotates, insulating film 130 gradually covers the outer peripheral surface of electrode assembly 120. During this process, the position of insulating film 130 relative to camera 43 changes continuously with the rotation of electrode assembly 120 until insulating film 130 is fully covered, at which point camera 43 is aligned with the ending end of the winding of insulating film 130. In other words, camera 43 can capture images of the outer surface of insulating film 130 corresponding to each angular interval of electrode assembly 120.

[0174] By acquiring images of the insulating film 130 during the rotation of the electrode assembly 120, and using these images to inspect the coating quality, the entire insulating film 130 can be inspected, not just the overlapping areas, which helps to improve the comprehensiveness and reliability of the inspection.

[0175] There are various ways to detect the coating quality of the insulating film 130 based on visual images. In some embodiments, the coating quality can be detected by utilizing the difference in color between the adhesive-coated area 133 and the empty film area 134 in the visual image. For example, if the substrate 131 is a transparent substrate and the adhesive layer 132 is light yellow, then the adhesive-coated area 133 will appear light yellow, while the first empty film area 134a and the second empty film area 134b will both be transparent. Thus, when the light yellow portions in the visual image overlap to form a deeper yellow, it indicates that the adhesive-coated areas 133 are overlapping, and the overlap state of the adhesive-coated areas 133 is unqualified, therefore the coating quality of the insulating film 130 is unqualified. When the visual image shows that the winding end overlaps outside the winding start end, it indicates that the coating integrity is qualified.

[0176] According to some embodiments of this application, when step S130 is performed, step S150 may also be performed simultaneously. S150: Detect the outer perimeter of the electrode assembly 120.

[0177] In this example, the process of inspecting the coating quality of the insulating film 130 and obtaining the quality inspection result based on a visual image may include the following steps.

[0178] Step 1: Determine the unfolded pattern of the insulating film 130 based on the visual image.

[0179] Step 2: Based on the unfolded diagram, determine the overall size and the first size; wherein, in the flattened state, the size of the insulating film 130 along the first direction is the overall size, and the size of the adhesive coating area 133 along the first direction is the first size.

[0180] Step 3: Determine the quality inspection results based on the overall size, the first size, and the outer contour perimeter of the electrode assembly 120 (i.e., the second size).

[0181] In S150, the diameter of the cylindrical electrode assembly 120 can be detected, and the outer perimeter of the electrode assembly 120 can be calculated based on the diameter and set as the second dimension. As an example, a camera 43 can be positioned aligned with the end face of the electrode assembly 120 along its own axial direction. The camera 43 can acquire an image of the end face of the electrode assembly 120, thereby determining the diameter of the electrode assembly 120. As an example, an encoder can also be used to measure the diameter of the electrode assembly 120.

[0182] In step 1, as mentioned earlier, each time the electrode assembly 120 rotates a certain angle, the camera 43 can capture a visual image of the corresponding insulating film 130. These visual images are then stitched together sequentially according to the acquisition time to form an unfolded image of the insulating film 130. The unfolded image refers to the image of the insulating film 130 in a flattened state. Step 1 is equivalent to smoothing the insulating film 130 to... Figure 10 The flattened state shown.

[0183] In step 2, the glue-coating area 133 can be distinguished by the different colors of the glue-coating area 133 and the empty film area 134, thus determining the first dimension.

[0184] In step 3, based on the first dimension and the second dimension, the ratio of the first dimension to the second dimension can be calculated. When the ratio of the first dimension to the second dimension does not exceed 99%, it indicates that the adhesive application area 133 does not overlap, and the overlap state of the adhesive application area 133 is qualified. Based on the second dimension and the total dimension, the ratio of the total dimension to the second dimension can be calculated. When the ratio of the total dimension to the second dimension is greater than 1, it indicates that the winding start end and the winding end end overlap, and the wrapping integrity is qualified.

[0185] Adopting this technical solution, it depends on visual images to determine the first dimension and the second dimension, and then compares the first dimension and the second dimension with the total dimension to achieve the detection of the coating quality. This embodiment enables the quantification of the coating quality evaluation method and reduces the dependence on the color in the visual image, which is conducive to making the coating quality evaluation more reliable.

[0186] In some embodiments, the coating quality may further include the morphology of the insulating film. The morphology of the insulating film refers to the appearance morphology after the insulating film 130 is coated on the electrode assembly 120. That is, in addition to detecting the coating integrity and the overlapping state of the glue application area 133, the morphology of the insulating film is also detected. In this example, when the appearance of the insulating film 130 has no wrinkles and the insulating film 130 does not warp, the morphology of the insulating film is qualified. During the implementation of S310, the morphology of the insulating film can be detected according to the visual image collected by the camera 43.

[0187] An embodiment of the third aspect of the present application provides a coating device 40 for an electrode assembly 120, which is used to implement any of the above coating methods for the electrode assembly 120. The coating device 40 can be specifically applied after the manufacturing process of the electrode assembly 120 and before the process of inserting the electrode assembly 120 into the shell. The coating device 40 includes an electrode providing component, a film providing component, and a film coating component. The electrode providing component is used to provide the electrode assembly 120, the film providing component is used to provide the insulating film 130, the insulating film 130 includes a glue application area 133 and a film-free area 134, and at least one end of the glue application area 133 in the first direction is connected to the film-free area 134, and the first direction is perpendicular to the thickness direction of the glue application area 133. The film coating component is used to wind and coat the insulating film 130 around the outer periphery of the electrode assembly 120. The glue application area 133 and the film-free area 134 are successively wound around the electrode assembly 120, and at least part of the winding start end and the winding end of the insulating film 130 in its own winding direction overlap, wherein the glue application area 133 is arranged on at least part of the outer periphery of the electrode assembly 120, and at most one of the winding start end and the winding end includes a part of the glue application area 133.

[0188] In some embodiments, the film providing component can be configured to be specifically used for: providing an insulating film core 30, wherein the insulating film core 30 includes a plurality of insulating films 130 connected in sequence along the length direction of the insulating film core 30, the insulating film 130 includes a glue application area 133 and a film-free area 134, and at least one end of the glue application area 133 in the length direction of the insulating film core 30 is connected to the film-free area 134; unwinding and unfolding the insulating film core 30 into a strip-shaped film material; cutting the first insulating film 31 from the strip-shaped film material, wherein along the running path of the strip-shaped film material, the first insulating film 31 is the insulating film 130 at the front end of the strip-shaped film material.

[0189] In some embodiments, the first insulating film 31 includes two empty film regions 134, namely a first empty film region 134a and a second empty film region 134b, wherein the first empty film region 134a is located at the front end of the second empty film region 134b. In this example, the film supply assembly can also be configured to: obtain the distance between the first empty film region 134a and the second empty film region 134b along the length direction of the strip film and set it as a first distance; and cut the first insulating film 31 from the strip film in response to the first distance being within a first preset range.

[0190] In some embodiments, the adhesive coating area 133 has a marking portion 1331 on the side opposite to the electrode assembly 120. In this example, the film supply assembly can also be configured to: obtain the distance between the marking portion 1331 on the first insulating film 31 and the first empty film area 134a or the second empty film area 134b along the length direction of the strip film and set it as a second distance; in response to the first distance being within a first preset range and the second distance being within a second preset range, cut the first insulating film 31 from the strip film.

[0191] In some embodiments, the coating equipment 40 may further include a quality inspection module and a control module. After the coating assembly rolls the insulating film 130 around the outer periphery of the electrode assembly 120, the quality inspection module is used to perform coating quality inspection on the insulating film 130 and obtain the quality inspection result. The control module is used to respond to the quality inspection result to indicate that the coating quality of the insulating film 130 is qualified, and to allow the electrode assembly 120 to be transferred to the next process.

[0192] In some embodiments, the coating assembly can be configured to: attach the starting end of the winding of the insulating film 130 to the outer peripheral surface of the electrode assembly 120; and rotate the electrode assembly 120 about its own axis so that the insulating film 130 is wound around and covers the outer periphery of the electrode assembly 120. Furthermore, the coating device 40 may also include an image acquisition element, which acquires a visual image of the insulating film 130 while the coating assembly is winding and covering the outer periphery of the electrode assembly 120. The quality inspection module is configured to perform coating quality inspection on the insulating film 130 based on the visual image and obtain a quality inspection result.

[0193] In some embodiments, the coating device 40 may further include a detection unit, which is used to detect the outer perimeter of the electrode assembly 120 while the coating assembly rolls the insulating film 130 around the outer perimeter of the electrode assembly 120.

[0194] In this example, the quality inspection module is specifically configured to: determine the unfolded view of the insulating film 130 based on a visual image; determine the total size and a first size in the flattened state based on the unfolded view; wherein, in the flattened state, the size of the insulating film 130 along the first direction is the total size, and the size of the adhesive coating area 133 along the first direction is the first size; and determine the quality inspection result based on the total size in the flattened state, the first size, and the outer contour perimeter of the electrode assembly 120.

[0195] An embodiment of the fourth aspect of this application provides a battery device, such as... Figure 2 As shown, it includes the battery cell 11 in the above embodiments. It is understood that the battery device provided in this application, by using any of the above-described battery cells 11, has all the beneficial effects of the battery cells 11, which will not be repeated here.

[0196] An embodiment of the fifth aspect of this application provides an electrical device including the battery device described in the above embodiments, the battery device being used to provide electrical energy. The electrical device includes vehicles (such as vehicles, electric vehicles, ships, spacecraft, etc.), display devices (such as mobile phones, tablets, laptops, etc.), electric toys, power tools, etc. It is understood that the electrical device provided in this application, by utilizing any of the aforementioned battery cells 11, possesses all the beneficial effects of the aforementioned battery cells 11, which will not be elaborated further here.

[0197] An embodiment of the sixth aspect of this application provides an energy storage device, which includes the battery device described in the above embodiments, the battery device being used for energy storage. The energy storage device may include, but is not limited to, centralized energy storage devices (e.g., containerized energy storage devices), distributed energy storage devices, mobile energy storage devices, wearable energy storage devices, and so on.

[0198] It is understood that the energy storage device provided in this application, by using any of the aforementioned battery cells 11, has all the beneficial effects of the aforementioned battery cells 11, which will not be elaborated here.

[0199] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application.

[0200] A specific embodiment of this application is described below. It should be understood that this specific embodiment is described for illustrative purposes only and should not be construed as limiting the scope of this application.

[0201] The insulating film 130 is wrapped around the outer periphery of the electrode assembly 120 using the following steps.

[0202] Step a, provide electrode assembly 120, which is a cylindrical wound structure.

[0203] Step b: Provide an insulating film core 30. The insulating film core 30 includes a plurality of insulating films 130 connected sequentially along the length direction of the insulating film core 30. Each insulating film 130 includes an adhesive coating area 133 and an empty film area 134. At least one end of the adhesive coating area 133 along the length direction of the insulating film core 30 is connected to the empty film area 134. Unwind the insulating film core 30 into a strip film. Along the tape path of the strip film, the insulating film 130 at the foremost end of the strip film is the first insulating film 31. The first insulating film 31 includes an adhesive coating area 133 and two empty film areas 134. The adhesive coating area 133 is provided with a marking portion 1331. The two empty film areas 134 are respectively connected to the two ends of the adhesive coating area 133. The two empty film areas 134 are the first empty film area 134a and the second empty film area 134b, respectively. The first empty film area 134a is located at the foremost end of the second empty film area 134b.

[0204] Step c: Obtain the distance between the first empty membrane region 134a and the second empty membrane region 134b along the length direction of the strip membrane material and set it as the first distance; obtain the distance between the marking portion 1331 on the first insulating film 31 and the first empty membrane region 134a or the second empty membrane region 134b along the length direction of the strip membrane material and set it as the second distance.

[0205] In step d, in response to the first distance being within a first preset range and the second distance being within a second preset range, the first insulating film 31 is cut from the strip film material.

[0206] Step e: The starting end of the first insulating film 31 is attached to the outer peripheral surface of the electrode assembly 120, and the electrode assembly 120 is rotated around its own axis, so that the insulating film 130 is wound and covers the entire outer periphery of the electrode assembly 120. After the covering is completed, the adhesive coating area 133 on the insulating film 130 is disposed on part of the outer periphery of the electrode assembly 120. The end of the adhesive coating area 133 near the second empty film area 134b and the second empty film area 134b are both superimposed on the outside of the first empty film area 134a. During the winding process of the insulating film 130, a visual image of the insulating film 130 is also acquired and the outer contour perimeter of the electrode assembly 120 is detected. The outer contour perimeter of the electrode assembly 120 is the second dimension.

[0207] Step f: Based on the visual image, determine the unfolded view of the insulating film 130; based on the unfolded view, determine the overall size and the first size; in the flattened state, the size of the insulating film 130 along the first direction is the overall size, and the size of the adhesive coating area 133 along the first direction is the first size; based on the overall size, the first size, and the outer perimeter of the electrode assembly 120, when the ratio of the first size to the second size is 80%~99% and the ratio of the overall size to the second size is greater than 1, determine that the covering quality of the insulating film 130 is qualified, and allow the electrode assembly 120 to proceed to the next process. The first direction, the second direction, and the thickness direction of the adhesive coating area 133 are perpendicular to each other. When the insulating film 130 covers the electrode assembly 120, the second direction is parallel to the axial direction of the electrode assembly 120.

[0208] This allows the insulating film 130 to be wound around and cover the entire outer periphery of the electrode assembly 120. The insulating film 130 has a winding start end and a winding end along its own winding direction. The winding start end is formed by the first empty film region 134a, and the winding end end is formed by the second empty film region 134b and a portion of the adhesive coating region 133. The adhesive coating region 133 is disposed on a portion of the outer periphery of the electrode assembly 120.

[0209] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A battery cell, characterized in that, include: Electrode assembly; An insulating film is wound around the outer periphery of the electrode assembly. The insulating film has a winding start end and a winding end along its winding direction, and the winding start end and the winding end at least partially overlap. The insulating film includes an adhesive coating area and two empty film areas. The two empty film areas correspond one-to-one with the two ends of the adhesive coating area along the winding direction and are connected. The adhesive coating area is disposed on at least a portion of the outer periphery of the electrode assembly, and at most one of the winding start end and the winding end includes a portion of the adhesive coating area. The dimension of the adhesive coating area along the winding direction is a first dimension, and the sum of the dimensions of all the empty film areas along the winding direction is a third dimension. The first dimension is greater than the third dimension.

2. The battery cell according to claim 1, characterized in that, The one of the two empty membrane regions that is closer to the center of the electrode assembly is used as the winding start end.

3. The battery cell according to claim 1 or 2, characterized in that, The winding end includes a portion of the adhesive coating area.

4. The battery cell according to claim 1 or 2, characterized in that, The perimeter of the outer contour of the electrode assembly is the second dimension, and the first dimension is 80% to 99% of the second dimension.

5. The battery cell according to claim 4, characterized in that, The ratio of the third dimension to the first dimension is 1:4 to 1:

50.

6. A method for coating an electrode assembly, characterized in that, include: Provide electrode assemblies; An insulating film is provided, wherein the insulating film includes an adhesive coating area and two empty film areas, the two empty film areas correspond one-to-one with and are connected to the two ends of the adhesive coating area along a first direction, the first direction is perpendicular to the thickness direction of the adhesive coating area, the dimension of the adhesive coating area along the first direction is a first dimension, the sum of the dimensions of all the empty film areas along the first direction is a third dimension, and the first dimension is greater than the third dimension; The insulating film is wound around the outer periphery of the electrode assembly. The adhesive coating area and the empty film area are wound onto the electrode assembly in sequence, and the starting end and the ending end of the winding of the insulating film along its own winding direction at least partially overlap. The adhesive coating area is disposed on at least a portion of the outer periphery of the electrode assembly, and at most one of the starting end and the ending end includes a portion of the adhesive coating area.

7. The coating method according to claim 6, characterized in that, The provision of the insulating film includes: An insulating film roll core is provided, wherein the insulating film roll core includes a plurality of insulating films connected sequentially along the length direction of the insulating film roll core, the insulating film includes an adhesive coating area and an empty film area, and at least one end of the adhesive coating area along the length direction of the insulating film roll core is connected to the empty film area; The insulating film core is unwound and unfolded into a strip of film. The first insulating film on the strip film is cut from the strip film, wherein, along the tape path of the strip film, the first insulating film is the insulating film at the very front end of the strip film.

8. The coating method according to claim 7, characterized in that, The first insulating film includes two empty film regions, which are a first empty film region and a second empty film region, respectively, with the first empty film region located at the front end of the second empty film region; The step of cutting the first insulating film on the strip film from the strip film includes: The distance between the first empty membrane region and the second empty membrane region along the length direction of the strip membrane material is obtained and set as the first distance; In response to the first distance being within a first preset range, the first insulating film is cut from the strip film material.

9. The coating method according to claim 8, characterized in that, The adhesive coating area is provided with a marking part on the side opposite to the electrode assembly; The step of cutting the first insulating film from the strip film material includes: The distance between the marking portion on the first insulating film and the first empty film area or the second empty film area along the length direction of the strip film material is obtained and set as the second distance; In response to the first distance being within a first preset range and the second distance being within a second preset range, the first insulating film is cut from the strip film material.

10. The coating method according to any one of claims 6 to 9, characterized in that, After the insulating film is wound and wrapped around the outer periphery of the electrode assembly, the wrapping method further includes: The insulating film was subjected to coating quality inspection, and the quality inspection results were obtained; In response to the quality inspection results indicating that the coating quality of the insulating film is qualified, the electrode assembly is transferred to the next process.

11. The coating method according to claim 10, characterized in that, The step of wrapping the insulating film around the outer periphery of the electrode assembly includes: The starting end of the winding of the insulating film is attached to the outer peripheral surface of the electrode assembly; The electrode assembly is rotated about its own axis, so that the insulating film is rolled up and covered around the outer periphery of the electrode assembly; While the insulating film is rolled up and wrapped around the outer periphery of the electrode assembly, a visual image of the insulating film is acquired. The process of performing coating quality inspection on the insulating film and obtaining the quality inspection results includes: Based on the visual image, the coating quality of the insulating film is inspected, and the quality inspection result is obtained.

12. The coating method according to claim 11, characterized in that, While the insulating film is rolled and wrapped around the outer periphery of the electrode assembly, the outer contour perimeter of the electrode assembly is also detected. The process of detecting the coating quality of the insulating film based on the visual image and obtaining the quality detection result includes: Based on the visual image, the unfolded pattern of the insulating film is determined; Based on the unfolded diagram, the overall size and the first size are determined; wherein, in the flattened state, the size of the insulating film along the first direction is the overall size, and the size of the adhesive coating area along the first direction is the first size; The quality inspection result is determined based on the total size, the first size, and the outer contour perimeter of the electrode assembly.

13. A battery device, characterized in that, Includes the battery cell as described in any one of claims 1 to 5.

14. An electrical appliance, characterized in that, The electrical equipment includes the battery device as described in claim 13, the battery device being used to provide electrical energy.

15. An energy storage device, characterized in that, The energy storage device includes the battery device as described in claim 13, the battery device being used to store electrical energy.

Images