Battery cell, battery device, power consuming device, and method for producing battery cell

Abstract

The application belongs to the technical field of batteries, and provides a battery monomer, a battery device, a power consumption device and a preparation method of the battery monomer. The battery monomer comprises an insulating film, the insulating film comprises a top film and two side combination films, the top film is attached to a top surface; the two side combination films are respectively arranged on opposite sides of the top film, each side combination film comprises a first side film, a first bottom film and two second side films, the first side film is attached to a first side surface; the second side film is connected to the first side film, and the second side film is attached to a second side surface; the top film and the first bottom film are respectively connected to two sides of the first side film, and the first bottom film is attached to a bottom surface; the side combination film further comprises two second bottom films, the second bottom films are arranged at two ends of the first bottom film, the second bottom films are connected to one end of the second side film, and the second bottom films are attached to the first bottom film; the first side film has a third positioning structure; a cover body assembly has a fourth positioning structure, and the third positioning structure and the fourth positioning structure are insertedly connected. The application can improve the assembly quality of the battery monomer.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to a battery cell, a battery device, an electrical device, and a method for preparing a battery cell. Background Technology

[0002] Lithium-ion batteries are widely used in new energy vehicles, energy storage devices, and other fields due to their high energy density and long cycle life. In the structural design of lithium-ion prismatic batteries, a single battery cell typically includes a casing, an electrode assembly housed within the casing, and an insulating film (Mylar film) for insulation protection. The electrode assembly includes multiple stacked electrode components.

[0003] In the structural design of lithium-ion prismatic batteries, the electrode assembly needs to be covered with an insulating film and assembled inside the casing. In related technologies, the electrode assembly, insulating film and casing are prone to displacement and misalignment during the assembly process, which affects the overall assembly quality of the battery and thus the battery performance. Summary of the Invention

[0004] The purpose of this application is to provide a battery cell, a battery device, an electrical device, and a method for preparing a battery cell, aiming to solve the technical problem of poor assembly quality of electrode assemblies, insulating films, and casings during the preparation of battery cells.

[0005] In a first aspect, this application provides a battery cell, including a housing and an electrode assembly housed within a cavity of the housing. The electrode assembly includes at least one electrode component, and the electrode assembly has a top surface, a bottom surface, two opposing first side surfaces, and two opposing second side surfaces. The housing includes a housing body and a cover assembly, the cover assembly being connected to the housing body and together with the housing body forming the cavity. The battery cell also includes an insulating film, the insulating film comprising:

[0006] The top membrane is attached to the top surface, and the top membrane is positioned opposite to the cover assembly.

[0007] The system includes two side-combination membranes, each disposed on opposite sides of the top membrane. Each side-combination membrane comprises a first side membrane, a first bottom membrane, and two second side membranes. The two first side membranes are respectively bonded to two corresponding first side membranes. In a first direction, the two second side membranes are respectively bonded to both sides of the first side membrane. Two second side membranes on the same side are laminated and bonded to one second side membrane, and the other two second side membranes on the same side are laminated and bonded to another second side membrane. In a second direction, the top membrane and the first bottom membrane are respectively bonded to both sides of the first side membrane. Two first bottom films are laminated and bonded to the bottom surface, with the first direction perpendicular to the second direction; at least one side assembly film also includes two second bottom films, which are disposed at both ends of the first bottom film in the first direction, and are connected to the end of the second side film near the first bottom film, and are laminated and bonded to the bottom surface or the first bottom film; the end of the first side film facing the cover assembly has a third positioning structure protruding from the edge of the first side film; the side of the cover assembly facing the top film has a fourth positioning structure, and the third positioning structure and the fourth positioning structure are interlocked along the second direction.

[0008] In this embodiment, by setting a third positioning structure on the first side film of the side composite film and a corresponding fourth positioning structure on the cover assembly of the outer shell, the top film is positioned opposite the cover assembly during the assembly and positioning of the electrode assembly, the side composite film, and the outer shell, and the third positioning structure and the fourth positioning structure are interlocked. This further improves the positioning reliability between the insulating film and the cover assembly, reduces the risk of displacement of the insulating film relative to the cover assembly, and achieves the initial positioning of the electrode assembly, the side composite film, and the cover assembly. Then, the entire outer surface of the electrode assembly is correspondingly wrapped with different parts of the insulating film, so that the electrode assembly and the side shell wall of the outer shell and the outer shell are effectively insulated, which can reduce the risk of short circuit. The overlapping wrapping method can also increase the tightness and reliability of the wrapping, thereby improving the insulation reliability.

[0009] In one embodiment, a second side film in one side composite film has a first width, and a second side film in another side composite film has a second width, the second width being less than the first width, and the sum of the first width and the second width being greater than the width of the second side film;

[0010] A first bottom film in one side-mounted membrane has a third width, and a first bottom film in another side-mounted membrane has a fourth width, the fourth width being less than the third width, and the sum of the third width and the fourth width being greater than the width of the bottom surface.

[0011] In this embodiment, by controlling the widths of the two second side films and the two first bottom films stacked together, it is possible to save materials, reduce the risk of interference between the stacked film layers, and improve the reliability of the stacked seal.

[0012] In one embodiment, the second width is 0.25 to 0.75 times the first width; and / or, the fourth width is 0.25 to 1.0 times the third width.

[0013] In this embodiment, by controlling the width of the two overlapping film layers, it is possible to protect the surface of the electrode assembly while also saving the amount of insulating film material and improving the reliability of sealing and insulation.

[0014] In one embodiment, the second bottom membrane has a preset width, which is less than or equal to the width of the second side membrane that is matched and connected to it.

[0015] In this embodiment, by making the width of the second bottom film less than or equal to the corresponding second side film, it is easier to stack the first bottom film and the second bottom film, reducing the risk of interference, thereby improving the regularity of the insulating film sheet and making it easier to prepare.

[0016] In one embodiment, the second base film has a preset length, which is equal to the size of the first base film that it matches.

[0017] In this embodiment, by matching the length of the second base film to the size of the corresponding first base film, the regularity of the insulating film sheet is improved, and it is also easier to prepare.

[0018] In one embodiment, the electrode assembly has tabs; the electrode assembly also includes an adapter, and the battery cell also includes an electrode terminal and an explosion-proof valve. The electrode assembly and the adapter are both disposed within a receiving cavity; the tabs on the electrode assembly are electrically connected to the electrode terminals via the adapter, and the electrode terminals and the explosion-proof valve are both connected to the outer casing; a top membrane covers the tabs; the top membrane has a first clearance hole and a second clearance hole, the explosion-proof valve is disposed opposite to the first clearance hole, and the connection position of the adapter and the electrode terminal is disposed opposite to the second clearance hole.

[0019] In this embodiment, by opening the first clearance hole and the second clearance hole, the safe pressure relief function of the explosion-proof valve and the welding quality of the adapter can be maintained without affecting the circuit connection problem and venting problem of the battery caused by the interference of the insulating film.

[0020] In one embodiment, the top film has a first positioning structure and the cover assembly has a second positioning structure, and the first positioning structure and the second positioning structure are interlocked along a second direction.

[0021] In this embodiment, by setting a first positioning structure and a second positioning structure, the assembly positioning accuracy of the insulating film can be improved, ensuring the normal realization of core functions such as opening the explosion-proof valve and welding the adapter, reducing the risk of insulation failure caused by the displacement of the insulating film, and improving the battery assembly quality.

[0022] In one embodiment, the cover assembly includes a cover and a lower plastic, the cover and the shell body together enclosing a receiving cavity, the lower plastic is connected to the cover and disposed on the side of the cover facing the receiving cavity, and a second positioning structure is disposed on the lower plastic.

[0023] In this embodiment, by setting a lower plastic layer and placing the second positioning structure on it, the battery's insulation safety performance is enhanced while ensuring positioning accuracy. This reduces the risk of short circuits caused by improper material or layout of the positioning structure, and improves the stability of assembly quality. It also improves the long-term stability and anti-aging performance of individual battery cells, extends their service life, and enhances their reliability under complex operating conditions.

[0024] In one embodiment, the cover assembly includes a cover and a lower plastic, the cover and the shell body together enclosing a receiving cavity, the lower plastic is connected to the cover and disposed on the side of the cover facing the receiving cavity, and a fourth positioning structure is disposed on the cover.

[0025] In this embodiment, by setting a cover and a lower plastic layer, and placing the fourth positioning structure on the cover, the battery's insulation safety performance is enhanced while ensuring positioning accuracy. This reduces the risk of short circuits caused by improper materials or unreasonable layout of the positioning structure, and improves the stability of assembly quality. It also improves the long-term stability and anti-aging performance of individual battery cells, extends their service life, and enhances their reliability under complex operating conditions.

[0026] In one embodiment, the cover assembly includes a cover and a lower plastic, the cover and the shell body together enclosing a receiving cavity, the lower plastic being connected to the cover and disposed on the side of the cover facing the receiving cavity; along a first direction, one or both ends of the lower plastic have positioning protrusions, and corresponding to the positioning protrusions, one or both ends of the top film have clearance areas; the positioning protrusions are confined between two first side films by the clearance areas.

[0027] In this embodiment, positioning protrusions are provided at both ends of the lower plastic, and correspondingly, avoidance areas are provided at both ends of the top film. After the two positioning protrusions pass through the corresponding avoidance areas, they are located between the two first side films. This double-sided positioning structure can further improve the stability of the cover assembly assembly, ensure the fitting accuracy between the cover and the shell body, and reduce the problem of assembly offset.

[0028] Secondly, this application provides a battery device, which includes a battery cell as described in any of the above.

[0029] Thirdly, this application provides an electrical device including a battery cell as described above; or, the electrical device includes a battery device as described above, the battery device being used to store or provide electrical energy.

[0030] Fourthly, this application provides a method for preparing a single battery cell, the method comprising the following steps:

[0031] Sheets of materials for prefabricating insulating films in battery cells as described in any of the above-mentioned items;

[0032] Prefabricated electrode assembly;

[0033] At the preset workstation, the cover assembly, insulating film, and electrode assembly are placed separately using a separate feeding method. The insulating film is in a sheet-like unfolded state, with the top film of the insulating film aligning with the inner side of the cover assembly. The electrode assembly is then assembled and positioned with the insulating film, with the third positioning structure and the fourth positioning structure interlocked. The two first side films in the insulating film are respectively attached to the two first side films in the electrode assembly.

[0034] The first bottom film is covered, and the two first bottom films are folded in sequence so that the two first bottom films are attached to and stacked with the bottom surface of the electrode assembly;

[0035] The second side film is covered, and the four second side films are folded toward the corresponding second side of the electrode assembly, so that two second side films are attached and stacked on each second side; correspondingly, the four second bottom films are stacked in pairs.

[0036] The second bottom film is covered, and the two correspondingly stacked second bottom films are folded towards the bottom surface of the electrode assembly, so that the two stacked second bottom films are respectively attached and stacked with the first bottom film;

[0037] Electrically connect the electrode terminals and weld the electrode terminals to the electrode assembly;

[0038] The encapsulated electrode assembly is then inserted into the housing cavity of the outer shell, thus sealing the cover assembly with the shell body.

[0039] In one embodiment, the electrode assembly includes an adapter and at least two electrode assemblies;

[0040] The step of prefabricating an electrode assembly includes connecting the tabs of at least two electrode assemblies to an adapter to form an electrode assembly;

[0041] The steps of assembling and positioning the electrode assembly with the insulating film, wherein the two first side films in the insulating film are respectively attached to the two first sides of the electrode assembly, include: at a preset station, positioning and connecting the electrode tab and the adapter to the top film of the insulating film, and respectively matching and attaching the two first side films in the insulating film to the two first sides of the outer electrode assembly in the electrode assembly; and folding the core, stacking the electrode assemblies so that the first sides of adjacent electrode assemblies are opposite or attached to each other, maintaining the two first side films respectively attached to the two first sides of the outer electrode assembly.

[0042] In this embodiment, the electrode assembly with multiple electrode components can be positioned and connected to the top film of the insulating film by positioning the tabs and adapters together. At the same time, the two first side films in the insulating film are respectively matched and attached to the two first side films of the outer electrode components in the electrode assembly. Then, the core is joined together, so that the entire outer surface of the electrode assembly is covered by different parts of the insulating film, which effectively insulates the electrode components from the side walls of the outer shell and from the outer shell. This reduces the risk of short circuits. The overlapping wrapping method also increases the tightness and reliability of the wrapping, thereby improving the insulation reliability.

[0043] In one embodiment, after the step of covering the second base film, adhesive is applied to the bottom surface and the portion of the second side surface of the electrode assembly near the bottom surface, such that the adhesive covers at least the second base film, at least a portion of the first base film, and at least a portion of the second side film.

[0044] In this embodiment, the colloid covering design eliminates the relative displacement space between the bottom film and the side film. Combined with the overlapping structure of the second bottom film and the first bottom film, it further enhances the overall covering stability of the insulating film, ensuring that problems such as bottom film detachment and side film displacement will not occur during long-term use. It also increases the height of the bottom surface of the electrode assembly, making it less likely for the bottom corners of the electrode assembly to touch the arc-shaped chamfer at the bottom of the outer shell.

[0045] In one embodiment, the preparation method does not require a heat-melting process for the insulating film.

[0046] In this embodiment, no hot-melting process is required, which can protect the core components of the electrode assembly (such as the separator), reduce the quality risks such as short circuits and insulation failures of individual battery cells, and improve the yield and reliability of the battery.

[0047] In one embodiment, the top membrane has a first clearance hole and a second clearance hole, and an explosion-proof valve is connected to the cover assembly; in the step where the electrode tab and the adapter are both positioned and connected to the top membrane of the insulating membrane, the method further includes setting the explosion-proof valve opposite to the first clearance hole, and setting the area of ​​the adapter connected to the electrode terminal opposite to the second clearance hole.

[0048] In this embodiment, during the process of assembling the top film with the tabs and adapters on the electrode assembly, the first clearance hole is matched with the explosion-proof valve, and the second clearance hole is matched with the welding position on the adapter. This reduces the risk of functional failure caused by misalignment of the clearance hole and ensures the reliability of the circuit connection of the battery cell.

[0049] In one embodiment, the top film has a first positioning structure and the cover assembly has a second positioning structure; in the step where the tabs and the adapter are both positioned and connected to the top film of the insulating film, the method further includes inserting and engaging the first positioning structure and the second positioning structure.

[0050] In this embodiment, the positioning structure improves the long-term stability and failure resistance of the insulating film coating, reduces battery failures caused by loosening of the insulating film, and enhances the environmental adaptability of the battery.

[0051] 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

[0052] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments of this application or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0053] Figure 1 This application provides structural schematic diagrams of vehicles for some embodiments;

[0054] Figure 2 This is an exploded view of the battery device provided in some embodiments of this application;

[0055] Figure 3 This is a schematic diagram of the structure of the electrode assembly in the battery device provided in some embodiments of this application;

[0056] Figure 4 This is an exploded structural diagram of a battery cell provided in some embodiments of this application;

[0057] Figure 5 This is a schematic diagram of the structure of the insulating film in a battery cell in a flat, unfolded state, provided in some embodiments of this application.

[0058] Figure 6This is a schematic diagram showing the dimensions of the insulating film in a battery cell in a flat, unfolded state, as provided in some embodiments of this application.

[0059] Figure 7 This is a schematic diagram of the structure in which the insulating film in a battery cell is stacked at the bottom of the electrode assembly, according to some embodiments of this application.

[0060] Figure 8 A schematic diagram of the inner side surface of the cover assembly in a battery cell provided in some embodiments of this application;

[0061] Figure 9 for Figure 5 A magnified view of a portion of position A in the diagram;

[0062] Figure 10 for Figure 5 A magnified view of a portion of position B in the diagram;

[0063] Figure 11 for Figure 8 A magnified view of the area at position C in the middle;

[0064] Figure 12 A schematic diagram of the structure of the electrode assembly covered with an insulating film and the cover assembly in a battery cell provided in some embodiments of this application;

[0065] Figure 13 A schematic diagram of the preliminary assembly process of the cover assembly, insulating film and electrode assembly during the battery cell manufacturing process provided in some embodiments of this application;

[0066] Figure 14 This is a schematic diagram showing the state of the battery cell after it has been assembled during the manufacturing process of some embodiments of this application;

[0067] Figure 15 This is a schematic diagram showing the state of a battery cell after the first base film has been bonded during the manufacturing process, as provided in some embodiments of this application.

[0068] Figure 16 This is a schematic diagram showing the state of a battery cell after the second side film has been attached during the manufacturing process, as provided in some embodiments of this application.

[0069] Figure 17 These are schematic diagrams showing the state of a battery cell after adhesive application during the manufacturing process, as provided in some embodiments of this application.

[0070] Figure 18 This is a schematic diagram of the internal structure of a battery cell provided in some embodiments of this application.

[0071] Explanation of reference numerals in the attached figures:

[0072] 1000, Vehicle; 1100, Battery assembly; 1110, Housing; 1111, First part; 1112, Second part; 1113, Receiving space; 1120, Battery cell; 1121, Housing; 11211, Cover assembly; 11212, Housing body; 11213, Receiving cavity; 11214, Cover; 11215, Lower plastic; 11216, Second positioning structure; 11217, Fourth positioning structure; 11218, Positioning protrusion; 1122, Electrode assembly; 11221, Electrode assembly; 11222, Tab; 11223, Top surface; 11224, First side surface; 11225, Second side surface; 112 26. Bottom surface; 11227. Chamfered corner; 11228. Bottom corner; 1123. Insulating film; 11231. Top film; 11232. Side composite film; 11233. First side film; 11234. Second side film; 11235. First bottom film; 11236. Second bottom film; 11237. First clearance hole; 11238. Second clearance hole; 11239. First positioning structure; 11240. Third positioning structure; 11241. Colloid; 11242. Clearance area; 1124. Electrode terminal; 1125. Explosion-proof valve; 1200. Controller; 1300. Motor; X, First direction; Y, Second direction; Z, Third direction. Detailed Implementation

[0073] 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.

[0074] 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.

[0075] 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.

[0076] 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.

[0077] 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.

[0078] 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).

[0079] 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.

[0080] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," 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 communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0081] With the rapid development of the new energy industry, lithium-ion batteries are widely used in new energy vehicles, energy storage equipment and other fields due to their advantages such as high energy density and long cycle life. In the structural design of lithium-ion prismatic batteries, a single battery cell typically includes a casing, an electrode assembly housed within the casing, and a Mylar film for insulation protection. The Mylar film is an insulating film, and the electrode assembly includes multiple stacked electrode components.

[0082] In the structural design of lithium-ion prismatic batteries, the electrode assembly needs to be covered with an insulating film and assembled inside the casing. In related technologies, the electrode assembly, insulating film and casing are prone to displacement and misalignment during the assembly process, which affects the overall assembly quality of the battery and thus the battery performance.

[0083] Therefore, this application provides a battery cell that improves the insulating film in the battery cell by setting a third positioning structure on the first side film of the side combination film and a corresponding fourth positioning structure on the cover assembly of the outer shell. When the electrode assembly, the side combination film, and the outer shell are assembled and positioned, the top film is positioned opposite the cover assembly, and the third positioning structure and the fourth positioning structure are inserted into each other. This further improves the positioning reliability between the insulating film and the cover assembly, reduces the risk of displacement of the insulating film relative to the cover assembly, and achieves the initial positioning of the electrode assembly, the side combination film, and the cover assembly. Then, the entire outer surface of the electrode assembly is correspondingly wrapped with different parts of the insulating film, so that the electrode assembly and the side shell wall of the outer shell and the outer shell are effectively insulated, which can reduce the risk of short circuit. The overlapping wrapping method can also increase the tightness and reliability of the wrapping, thereby improving the insulation reliability.

[0084] Specifically, refer to Figure 3 and Figure 4 As shown, this application embodiment provides a battery cell 1120, which includes a housing 1121 and an electrode assembly 1122 housed within a cavity 11213 of the housing 1121. The electrode assembly 1122 includes at least one electrode component 11221, and has a top surface 11223, a bottom surface 11226, two opposing first side surfaces 11224, and two opposing second side surfaces 11225. The housing 1121 includes a housing body 11212 and a cover assembly 11211, which is connected to the housing body 11212 and together with the housing body 11212 forms the cavity 11213. The battery cell 1120 also includes an insulating film 1123, which, in conjunction with... Figure 5-7As shown, the insulating film 1123 includes a top film 11231 and side combination films 11232. The top film 11231 is attached to the top surface 11223 and is disposed opposite to the cover assembly 11211. Two side combination films 11232 are provided, each disposed on opposite sides of the top film 11231. Each side combination film 11232 includes a first side film 11233, a first bottom film 11235, and two second side films 11234. The two first side films 11233 are respectively attached to the two first side films 11224 in a one-to-one correspondence. In the first direction X, the two second side films 11234 are respectively connected to the two sides of the first side film 11233. Two second side films 11234 located on the same side are laminated and attached to one second side film 1. On 1225, two other second side films 11234 located on the same side are laminated and bonded to another second side film 11225; in the second direction Y, the top film 11231 and the first bottom film 11235 are respectively connected to the two sides of the first side film 11233, and the two first bottom films 11235 are laminated and bonded to the bottom surface 11226, with the first direction X perpendicular to the second direction Y; at least one side composite film 11232 also includes two second bottom films 11236, in the first direction X, the two second bottom films 11236 are disposed at both ends of the first bottom film 11235, the second bottom films 11236 are connected to the end of the second side film 11234 near the first bottom film 11235, and the second bottom films 11236 are laminated and bonded to the bottom surface 11226 or the first bottom film 11235; Refer to Figure 4 , Figure 5 and Figure 8-11 As shown, the first side membrane 11233 has a third positioning structure 11240 protruding from the edge of the first side membrane 11233 at one end facing the cover assembly 11211; the cover assembly 11211 has a fourth positioning structure 11217 on the side facing the top membrane 11231, and the third positioning structure 11240 and the fourth positioning structure 11217 are interlocked along the second direction Y.

[0085] In this embodiment of the application, the battery cell 1120 can be a secondary battery. A secondary battery refers to a battery cell 1120 that can be used again after being discharged by recharging to activate the active materials.

[0086] The battery cell 1120 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 the embodiments of this application are not limited to this.

[0087] In this embodiment, the vertical orientation of battery cell 1120 is used as an example. Battery cell 1120 is a prismatic battery cell. Therefore, in conjunction with... Figure 3 As shown, the battery cell 1120 has a top, a bottom, and a side. Correspondingly, the electrode assembly 1122 has a top surface 11223, a bottom surface 11226, and multiple side surfaces (first side surface 11224 and second side surface 11225). The multiple side surfaces are located between the top surface 11223 and the bottom surface 11226. The multiple side surfaces may include two oppositely arranged first side surfaces 11224 and two oppositely arranged second side surfaces 11225. The first side surfaces 11224 and the second side surfaces 11225 are adjacent to each other and arranged perpendicularly.

[0088] Since the battery cell 1120 may include one or more electrode assemblies 11221, when the battery cell 1120 includes one electrode assembly 11221, the electrode assembly 11221 has a cubic external shape; when the battery cell 1120 includes multiple electrode assemblies 11221, the multiple electrode assemblies 11221 are stacked and arranged in one direction or two perpendicular directions to form an electrode assembly 1122 with a cubic external shape. In addition to including the electrode assembly 11221, the electrode assembly 1122 may also include an adapter (not shown in the figure), etc., which is electrically connected (e.g., welded) to the tabs 11222 of one or more electrode assemblies 11221. The adapter may be a sheet-shaped adapter plate.

[0089] For electrode assembly 11221, it can be understood as a bare cell. Electrode assembly 11221 needs to be electrically connected to electrode terminal 1124. For example, electrode assembly 11221 is electrically connected to electrode terminal 1124 through an adapter. Electrode assembly 11221 includes a positive electrode (positive electrode sheet), a negative electrode (negative electrode sheet), and a separator, with the separator disposed between the negative electrode and the positive electrode. During the charging and discharging process of battery cell 1120, active ions (e.g., lithium ions) repeatedly insert and extract between the positive and negative electrodes. The separator, disposed between the positive and negative electrodes, can prevent short circuits between the positive and negative electrodes while allowing active ions to pass through. Electrode assembly 11221 can be a wound structure, a stacked structure, or a hybrid structure of wound and stacked.

[0090] Therefore, it is understandable that when the electrode assembly 1122 includes an electrode component 11221, the top surface 11223 of the electrode assembly 1122 is the top surface of the electrode component 11221, the tabs 11222 of the electrode component 11221 are disposed on the top surface 11223, the bottom surface 11226 of the electrode assembly 1122 is the bottom surface of the electrode component 11221, the first side surface 11224 of the electrode assembly 1122 is two opposite exposed side surfaces on the electrode component 11221, and the second side surface 11225 is two opposite exposed side surfaces of the electrode component 11221 in a direction perpendicular to the first side surface 11224. It should be understood that the first side 11224 should be the large surface of the electrode assembly 11221, that is, the first side 11224 is the side with a larger area among the sides of the electrode assembly 11221. The first side 11224 is also the main expansion surface of the electrode assembly 11221. Then, the second side 11225 is the side with a relatively smaller area among the sides of the electrode assembly 11221.

[0091] When the electrode assembly 1122 includes multiple electrode components 11221, the top surface 11223 of the electrode assembly 1122 is a combination of the top surfaces of the multiple electrode components 11221 formed by stacking and arranging the multiple electrode components 11221. Typically, the tabs 11222 of the electrode components 11221 are disposed on the top surface 11223. Correspondingly, the bottom surface 11226 of the electrode assembly 1122 is a combination of the bottom surfaces of the multiple electrode components 11221 formed by stacking and arranging the multiple electrode components 11221. The first side surface 11224 of the electrode assembly 1122 is the exposed side surface of the two outermost electrode components 11221, and the second side surface 11225 is a combination of the exposed side surfaces of the multiple electrode components 11221 in the direction perpendicular to the first side surface 11224. It should be understood that the first side 11224 should be the large surface of the electrode assembly 11221, that is, the first side 11224 is the side with a larger area among the sides of the electrode assembly 11221. The first side 11224 is also the main expansion surface of the electrode assembly 11221. Then, the second side 11225 is the side with a relatively smaller area among the sides of the electrode assembly 11221.

[0092] In some embodiments, the positive electrode may be a positive electrode sheet, which may include a positive electrode current collector and a positive electrode active material disposed on at least one surface of the positive electrode current collector.

[0093] As an example, the positive current collector has two surfaces opposite each other in its own thickness direction, and the positive active material is disposed on either or both of the two opposite surfaces of the positive current collector.

[0094] As an example, the positive current collector can be a metal foil, a conductive polymer material, a carbon material, or a composite current collector. For example, as a metal foil, pure metals, alloys, or surface-treated metals can be used, including but not limited to stainless steel, copper, aluminum, nickel, titanium, or silver. The composite current collector may include a polymer material base layer and a metal layer. The composite current collector can be formed by forming a metal material (aluminum, aluminum alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0095] As an example, the positive electrode active material may include at least one of the following materials: lithium phosphate, lithium transition metal oxide, and their respective modified compounds. However, this application is not limited to these materials, and other conventional materials that can be used as positive electrode active materials for batteries may also be used. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium phosphate include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), lithium iron phosphate and carbon composites, lithium manganese phosphate (such as LiMnPO4), lithium manganese phosphate and carbon composites, lithium manganese iron phosphate, and lithium manganese iron phosphate and carbon composites. Examples of lithium transition metal oxides may include, but are not limited to, lithium cobalt oxides (such as LiCoO2), lithium nickel oxides (such as LiNiO2), lithium manganese oxides (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxides, lithium manganese cobalt oxides, lithium nickel manganese oxides, lithium nickel cobalt manganese oxides (such as LiNi1 / 3Co1 / 3Mn1 / 3O2 (also abbreviated as NCM333), LiNi0.5Co0.2Mn0.3O2 (also abbreviated as NCM523), LiNi0.5Co At least one of the following: 0.25Mn0.25O2 (also abbreviated as NCM211), LiNi0.6Co0.2Mn0.2O2 (also abbreviated as NCM622), LiNi0.8Co0.1Mn0.1O2 (also abbreviated as NCM811), lithium nickel cobalt aluminum oxide (such as LiNi0.8Co0.15Al0.05O2), and their modified compounds. Modified compounds refer to substances obtained by doping or coating, etc., based on the above-mentioned materials.

[0096] In some embodiments, the positive electrode can be a foamed metal. The foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloy, or foamed carbon, etc. When foamed metal is used as the positive electrode, the surface of the foamed metal may or may not contain a positive electrode active material. As an example, a positive electrode active material is filled and / or deposited within the foamed metal.

[0097] In some embodiments, the negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector.

[0098] As an example, the negative electrode current collector can be a metal foil, a conductive polymer material, a carbon material, or a composite current collector. For example, as a metal foil, pure metals, alloys, or surface-treated metals can be used, including but not limited to stainless steel, copper, aluminum, nickel, titanium, or silver. The composite current collector may include a polymer material substrate and a metal layer. The composite current collector can be formed by forming a metal material (copper, copper alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0099] As an example, the negative electrode sheet may include a negative electrode current collector and a negative electrode active material disposed on at least one surface of the negative electrode current collector.

[0100] As an example, the negative electrode current collector has two surfaces opposite each other in its own thickness direction, and the negative electrode active material is disposed on either or both of the two opposite surfaces of the negative electrode current collector.

[0101] As an example, the negative electrode active material may be a negative electrode active material known in the art for use in battery cell 1120. As an example, the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate, etc. Silicon-based materials may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. Tin-based materials may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys. However, this application is not limited to these materials, and other conventional materials that can be used as negative electrode active materials for battery cell 1120 may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0102] In some embodiments, the negative electrode can be a foamed metal. The foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloy, or foamed carbon, etc. When foamed metal is used as the negative electrode sheet, the surface of the foamed metal may or may not have a negative electrode active material.

[0103] As an example, negative electrode active materials can be filled or / and deposited within the negative electrode current collector.

[0104] In some embodiments, the positive current collector can be made of aluminum, and the negative current collector can be made of copper.

[0105] In some embodiments, the electrode assembly 11221 further includes an isolator disposed between the positive and negative electrodes.

[0106] In some embodiments, the separator is a separator membrane. This application does not impose any particular limitation on the type of separator membrane; any known porous separator membrane with good chemical and mechanical stability can be selected.

[0107] As an example, the main material of the separator can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramic. The separator can be a single-layer film or a multi-layer composite film, without particular limitation. When the separator is a multi-layer composite film, the materials of each layer can be the same or different, without particular limitation. The separator can be a single component located between the positive and negative electrodes, or it can be attached to the surfaces of the positive and negative electrodes. An inorganic particle coating, an organic particle coating, or an organic / inorganic composite coating can also be applied to the surface of the separator.

[0108] In some embodiments, the separator is a solid electrolyte. The solid electrolyte is disposed between the positive and negative electrodes, serving both to transport ions and to isolate the positive and negative electrodes.

[0109] The electrode assembly 11221 also includes a tab 11222. The tab 11222 is the internal current lead-out or lead-in terminal of the electrode assembly 11221 (bare cell). The tab 11222 is a core transition component connecting the internal electrode plates of the cell to the external circuit. The tab 11222 is directly connected to the positive and negative electrode plates and is connected to the current collector, undertaking the function of current conduction during cell charging and discharging. In this example, the tab 11222 can be either a positive or negative tab. When the tab 11222 is a positive tab, the connected electrode terminal 1124 is the positive electrode terminal 1124; when the tab 11222 is a negative tab, the connected electrode terminal 1124 is the negative electrode terminal 1124.

[0110] It should be noted that tab 11222 should be understood as tab cluster, which is formed by multiple sheet-like structures stacked together. Tab 11222 can be bent and form a bonding surface to fit and connect with the adapter. Tab 11222 and adapter can be connected by welding. For example, tab 11222 and adapter can be connected by ultrasonic welding. In this case, a welding area will be formed between tab 11222 and adapter. The size of the welding area will affect the current flow area of ​​battery cell 1120.

[0111] For the insulating film 1123, in the battery cell 1120, the insulating film 1123 is usually referred to as the Mylar film. The chemical nature of the insulating film 1123 is polyethylene terephthalate (PET) film. The insulating film 1123 has excellent insulation properties, high dielectric strength, effectively blocking current conduction, and its insulation performance is less affected by temperature and humidity, making it an ideal electrical isolation material. The insulating film 1123 exhibits high temperature resistance and dimensional stability, maintaining stable performance within a wide temperature range of -70℃ to 150℃. The biaxial stretching process gives it an extremely low thermal shrinkage rate, making it less prone to deformation and failure during battery charging and discharging temperature fluctuations. The insulating film 1123 has high mechanical strength, possessing excellent tensile strength, tear resistance, and abrasion resistance. Thin yet tough, it can withstand certain mechanical stresses during battery assembly without easily breaking. The insulating film 1123 exhibits excellent chemical stability, resisting acids, alkalis, and organic solvents (such as carbonate solvents in battery electrolytes). It will not chemically react with internal battery components, ensuring the long-term reliability of the battery. The insulating film 1123 is lightweight and thin, with a thickness ranging from a few micrometers to tens of micrometers, minimizing its impact on the overall size and weight of the battery while meeting functional requirements.

[0112] Reference Figure 4 and Figure 5 As shown, the insulating film 1123 serves as insulation within the battery cell 1120, and should cover the outer surface of the electrode assembly 1122. Specifically, the insulating film 1123 includes a top film 11231 and two side composite films 11232. The top film 11231 is disposed between the two side composite films 11232, that is, the two side composite films 11232 are respectively disposed on opposite sides of the top film 11231. For example, refer to... Figure 5As shown, with the insulating film 1123 in its unfolded sheet state, two side-mounted composite films 11232 are respectively disposed on opposite sides of the top film 11231 along a third direction Z, which is perpendicular to the first direction X. The top film 11231 is positioned opposite and in contact with the top surface 11223 of the electrode assembly 1122. The top film 11231 should at least cover the tabs 11222, so that when the cover assembly 11211 and the insulating film 1123 are assembled, the tabs 11222 on the side closer to the cover assembly 11211 do not require adhesive, as the top film 11231 can completely cover the tabs 11222, thus achieving tab coverage. The insulation and foolproof design of 11222 and cover assembly 11211 are more reliable than the hot-melt insulating film 1123 method in related technologies. This is because if the hot-melt method is used, the hot-melt point of the insulating film 1123 is at one end of the tab 11222. After hot-melt, there are gaps between the top film 11231 at the tab 11222 and the cover assembly 11211. If the hot-melt point shifts or falls off, there is a risk that the tab 11222 and the cover assembly 11211 will overlap. Therefore, in related technologies, the back of the tab 11222 in the form of hot-melt insulating film 1123 needs to be glued, which involves more steps and is not conducive to saving manufacturing costs.

[0113] For the outer casing 1121, refer to Figure 4 , Figure 5 and Figure 8 As shown, the outer casing 1121 includes a casing body 11212 and a cover assembly 11211. The cover assembly 11211 is connected to the casing body 11212 and together with the casing body 11212 forms an accommodating cavity 11213. The cover assembly 11211 (i.e., the top cover of the battery cell 1120) is a plate-shaped structure adapted to the open end of the casing body 11212. The cover assembly 11211 is fixedly connected to the open end of the casing body 11212 by welding or snap-fit, and together with the casing body 11212 forms a sealed accommodating cavity 11213. The inner side of the cover assembly 11211 (the side facing the accommodating cavity 11213) may also be provided with a lower plastic 11215, an explosion-proof valve 1125, and an electrode lead-out structure. The second positioning structure 11216 described below may be provided on the side of the cover assembly 11211 facing the top film 11231.

[0114] The top membrane 11231 and the cover assembly 11211 are disposed opposite to each other. The end of the first side membrane 11233 facing the cover assembly 11211 has a third positioning structure 11240 protruding from the edge of the first side membrane 11233. The side of the cover assembly 11211 facing the top membrane 11231 has a fourth positioning structure 11217. Along the second direction Y, the third positioning structure 11240 and the fourth positioning structure 11217 are interlocked.

[0115] Specifically, a third positioning structure 11240 is added to the first side membrane 11233. The third positioning structure 11240 is disposed on the edge of the first side membrane 11233 and protrudes from one end (upper end) of the cover assembly 11211. It is an insertion protrusion protruding from the edge of the first side membrane 11233. The protrusion direction of the insertion protrusion is along the second direction Y (i.e., perpendicular to the top membrane 11231). The third positioning structure 11240 is integrally formed with the first side membrane 11233 and uses the same insulating polymer material as the first side membrane 11233. Multiple third positioning structures 11240 can be provided at intervals along the length direction of the first side membrane 11233.

[0116] The fourth positioning structure 11217 is disposed on the cover assembly 11211 (on the side facing the top membrane 11231), corresponding one-to-one with the third positioning structure 11240. It can be a positioning groove (or positioning hole) that adapts to the insertion protrusion. The groove depth direction is also along the second direction Y. The cross-sectional shape and size of the positioning groove are precisely matched with the insertion protrusion of the third positioning structure 11240, and the groove depth is consistent with the protrusion height, ensuring that the two can be tightly inserted and fitted.

[0117] The fourth positioning structure 11217 can be integrally formed with the cover assembly 11211. When the top film 11231 is attached to the cover assembly 11211, the third positioning structure 11240 can be naturally aligned with the fourth positioning structure 11217 to achieve insertion and limiting.

[0118] The third positioning structure 11240 of the first side membrane 11233 and the fourth positioning structure 11217 on the cover assembly 11211 interlock to form a positioning system, ensuring that the relative position of the insulating membrane 1123 and the cover assembly 11211 is fixed and there is no displacement during subsequent assembly. The interlocking of the third positioning structure 11240 and the fourth positioning structure 11217 can further improve the positioning reliability between the insulating membrane 1123 and the cover assembly 11211, reduce the risk of displacement of the insulating membrane 1123 relative to the cover assembly 11211, and lay the foundation for the initial accurate positioning of the cover assembly 11211, the electrode assembly 1122, and the insulating membrane 1123.

[0119] For the side combination film 11232, the side combination film 11232 includes multiple parts. Specifically, both side combination films 11232 include a first bottom film 11235, a first side film 11233, and two second side films 11234. The first side film 11233 can be considered as a large film, that is, the area of ​​the first side film 11233 is relatively large. The first side film 11233 is used to attach and connect (or cover) to the first side surface 11224 of the electrode assembly 1122. It is known that the electrode assembly 1122 has two first side surfaces 11224. Therefore, a first side film 11233 is attached and connected to each first side surface 11224.

[0120] The first bottom film 11235 and the top film 11231 are respectively connected to opposite sides of the first side film 11233. That is, the first bottom film 11235 is connected to the side of the first side film 11233 away from the top film 11231. The direction of the line connecting (or opposite) the first bottom film 11235 and the top film 11231 can be defined as the second direction Y. The first bottom film 11235 is flipped relative to the first side film 11224 and then adhered to the bottom surface 11226. It should be understood that since the insulating film 1123 has two first bottom films 11235, then... Two first base films 11235 should be stacked sequentially. The first base film 11235 at the bottom layer is attached to the bottom surface 11226. The two first base films 11235 have overlapping and covering portions, so as to completely cover the bottom surface 11226. Furthermore, the stacking of the two first base films 11235 is such that the bottom surface 11226 of the electrode assembly 1122 can raise the thickness of the two first base films 11235 by at least 2La. For example, if the thickness of the first base film 11235 is La, then the bottom surface 11226 of the electrode assembly 1122 can be raised by a height of 2La.

[0121] In the first direction X, two second side films 11234 are respectively connected to both sides of the first side film 11233. The two second side films 11234 are bent relative to the first side film 11233 and then attached to the two second side surfaces 11225 of the electrode assembly 1122. It should be noted that since there are two side combination films 11232, it can be seen that two second side films 11234 are stacked (or overlapped) on each second side surface 11225. That is, at one end (or one side) of the first direction X, two second side films 11234 located on the same side are stacked and attached to one second side surface 11225, and at the other end (or another side) of the first direction X, two other second side films 11234 located on the same side are stacked and attached to another second side surface 11225. Through the stacking and attachment of the second side films 11234, the two second side surfaces 11225 can be completely covered.

[0122] This application also considers that the corner where the bottom wall and side wall of the outer casing connect is usually designed as an arc-shaped chamfer. Correspondingly, the electrode assembly has a bottom corner, which is the corner (or bend) where the bottom surface of the electrode assembly connects to the side surface. Therefore, when the electrode assembly is assembled into the outer casing, the bottom corner of the electrode assembly and the arc-shaped chamfer at the bottom of the outer casing are prone to interference, especially when the electrode assembly expands. The bottom corner of the electrode assembly will move towards the arc-shaped chamfer, causing them to press against each other. In related technologies, to reduce the risk of interference and damage to the electrode assembly caused by the bottom corner of the electrode assembly and the arc-shaped chamfer at the bottom edge of the outer casing, a base plate is usually provided at the bottom of the electrode assembly to elevate it and move the electrode assembly away from the bottom wall, thereby increasing the distance between the electrode assembly and the arc-shaped chamfer at the bottom of the outer casing and reducing the risk of interference. However, the preparation and processing of the base plate and its assembly with the outer casing increase manufacturing steps and require specialized tools and equipment, leading to increased manufacturing costs for the battery cells. In addition, the base plate has a certain weight, and adding a base plate is not conducive to the lightweighting of individual battery cells.

[0123] Based on this, the insulating film 1123 of this application also includes a second bottom film 11236. The second bottom film 11236 is provided in at least one side assembly film 11232, that is, the second bottom film 11236 is provided in both side assembly films 11232, or the second bottom film 11236 is provided in one of the side assembly films 11232. Regarding the location of the second bottom film 11236, since the second bottom film 11236 needs to be attached to the bottom surface 11226 of the electrode assembly 1122, the second bottom film 11236 is connected to the end of the second side film 11234 closest to the first bottom film 11235. That is, in the second direction Y, the second bottom film 11236 is located at the end of the second side film 11234 closest to the first bottom film 11235. For the side-mounted composite membrane 11232 with a second bottom film 11236, two second bottom films 11236 should be provided in the side-mounted composite membrane 11232. The two second bottom films 11236 should be provided at both ends of the first bottom film 11235 in the first direction X. The second bottom films 11236 are bent relative to the second side film 11234 and then attached to the bottom surface 11226 (or the first bottom film 11235) of the electrode assembly 1122. In this way, in the first direction X, one second bottom film 11236 will be attached to each end of the bottom surface 11226, so that the two ends of the bottom surface 11226 of the electrode assembly 1122 will maintain a consistent height.

[0124] It should be noted that in this embodiment, in the same direction, one end (or two ends) and one side (or both sides) have the same meaning, both indicating the position of one end (or two ends) in this direction. For example, in the first direction X, the two second bottom films 11236 are respectively disposed at both ends of the first bottom film 11235, which is the same as the two second bottom films 11236 being respectively disposed on both sides of the first bottom film 11235, and the defined structural design is the same.

[0125] So, referring to Figure 7 As shown, since the second bottom film 11236 is attached to the bottom surface 11226 of the electrode assembly 1122, the setting of the second bottom film 11236 further raises the height of the bottom surface 11226 of the electrode assembly 1122, by at least the thickness of the second bottom film 11236. For example, if the thickness of the second bottom film 11236 is Lb, then the bottom surface 11226 of the electrode assembly 1122 can be raised by at least Lb.

[0126] In some examples, both side-mounted composite films 11232 may each have a second bottom film 11236. That is, in the first direction X, the second bottom films 11236 located on the same side will be stacked (or overlapped) and bonded to the bottom surface 11226 or the first bottom film 11235. There will be four second bottom films 11236 in one insulating film 1123, and the two second bottom films 11236 located on the same side will be stacked and bonded. It can be seen that the stacked second bottom films 11236 further raise the height of the bottom surface 11226 of the electrode assembly 1122, at least increasing the thickness of two second bottom films 11236. For example, if the thickness of the second bottom film 11236 is Lb, then the bottom surface 11226 of the electrode assembly 1122 can be further raised by 2Lb (refer to...). Figure 7 (As shown). It can be seen that the arrangement of the first bottom film 11235 and the second bottom film 11236 allows the bottom surface to be raised by at least (2La+2Lb), which is greater than or equal to the thickness of the bottom support plate.

[0127] It should be noted that the bonding sequence of the first base film 11235 and the second base film 11236 can be twofold: one is to first bond the first base film 11235 to the bottom surface 11226, and then bond the second base film 11236 to the first base film 11235; the other is to first bond the second base film 11236 to the bottom surface 11226, and then bond the first base film 11235 to the second base film 11236.

[0128] Because the first base film 11235 and the second base film 11236 are stacked on the bottom surface 11226, the electrode assembly 1122 forms a combined film layer with a certain thickness on the bottom surface 11226. The thickness of the combined film layer is the thickness of the two first base films 11235 and at least one second base film 11236. After the electrode assembly 1122, which is wrapped with insulating film 1123, is installed into the receiving cavity 11213 of the housing 1121, the bottom surface 11226 of the electrode assembly 1122 can be raised due to the effect of the combined film layer. The height of this raising allows the bottom surface 11226 and bottom corner 11228 of the electrode assembly 1122 to be moved away from and avoid the arc chamfer 11227 at the bottom of the housing 1121, reducing the risk of interference (contact, compression) between the bottom corner 11228 and the arc chamfer 11227. The bottom of the electrode assembly 1122 (in the receiving cavity 11213) does not need to be provided with a bottom support plate, reducing the preparation and installation process of the bottom support plate, which is conducive to reducing the manufacturing cost of the battery cell 1120. In addition, the elimination of the bottom support plate can also reduce the weight of the battery cell 1120, which is conducive to weight reduction.

[0129] In addition, since there are many mating surfaces between the first bottom film 11235 and the second bottom film 11236 in the insulating film 1123, it is beneficial for the electrolyte to enter the electrode assembly 11221, thereby improving the wetting efficiency.

[0130] In this embodiment, by improving the insulating film 1123 in the battery cell 1120, a third positioning structure 11240 is provided on the first side film 11233 of the side combination film 11232, and a fourth positioning structure 11217 is correspondingly provided on the cover assembly 11211 of the outer casing 1121. When the electrode assembly 1122, the side combination film 11232, and the outer casing 1121 are assembled and positioned, the top film 11231 is positioned opposite to the cover assembly 11211, and the third positioning structure 11240 and the fourth positioning structure 11217 are inserted into each other. This can further improve the positioning reliability between the insulating film 1123 and the cover assembly 11211 and reduce the insulation film 1123's position. 23 reduces the risk of displacement of the cover assembly 11211 and achieves the initial positioning of the electrode assembly 1122, the side combination film 11232, and the cover assembly 11211, making it less likely for the three to shift or misalign, resulting in high positioning reliability. This improves the overall assembly quality of the battery cell 1120 and is beneficial to improving battery performance. In addition, the entire outer surface of the electrode assembly 1122 is correspondingly bonded and wrapped by different parts of the insulating film 1123, which effectively insulates the electrode assembly 11221 from the side shell wall of the outer shell 1121 and from the outer shell, reducing the risk of short circuit. The overlapping wrapping method also increases the tightness and reliability of the wrapping, thereby improving the insulation reliability.

[0131] Furthermore, the first bottom film 11235 and the second bottom film 11236 are laminated on the bottom surface 11226 of the electrode assembly 1122, which raises the height of the bottom surface 11226 of the electrode assembly 1122. This allows the bottom corner 11228 of the electrode assembly 1122 to be moved away from and avoid the arc-shaped chamfer 11227 at the bottom of the outer casing 1121, reducing the risk of interference between the bottom corner 11228 and the arc-shaped chamfer 11227, and reducing the risk of the electrode assembly 11221 being damaged by compression. This is beneficial to improving the service life and reliability of the electrode assembly 11221. The bottom of the electrode assembly 1122 does not need to be provided with a bottom support plate, which eliminates the preparation and installation process of the bottom support plate and helps to reduce the manufacturing cost of the battery cell 1120. Eliminating the bottom support plate can also reduce the weight of the battery cell 1120, which is beneficial to weight reduction.

[0132] In some embodiments, refer to Figure 5 and Figure 6 As shown, the second side membrane 11234 in one side composite membrane 11232 has a first width, and the second side membrane 11234 in the other side composite membrane 11232 has a second width. The second width is less than the first width, and the sum of the first width and the second width is greater than the width of the second side 11225.

[0133] Specifically, the width of the second side film 11234 should be understood as the extension width of the second side film 11234 in the direction perpendicular to and away from the first side film 11233. For example, when the insulating film 1123 is in a flat sheet state, two second side films 11234 are connected to both sides of the first side film 11233 along the first direction X. Then, the width of the second side film 11234 refers to the distance between the two side edges of the second side film 11234 in the first direction X.

[0134] For example, in one side-mounted membrane 11232, there are two second side-mounted membranes 11234, the width of which is Lc, i.e., the first width is Lc. The widths of the two second side-mounted membranes 11234 can be the same or different. In another side-mounted membrane 11232, there are two second side-mounted membranes 11234, the width of which is Ld. The widths of the two second side-mounted membranes 11234 can be the same or different, i.e., the second width is Ld. Therefore, the second width is made smaller than the first width.

[0135] Typically, the first width is equal to the width of the second side 11225 of the electrode assembly 1122. The width of the second side 11225 refers to the width between the two first sides 11224 of the electrode assembly 1122, so that the second side film 11234, after being attached to the second side 11225, can cover the entire second side 11225. Of course, the first width can also be smaller than the width of the second side 11225 of the electrode assembly 1122. However, the two stacked second side films 11234 should have at least an overlapping (or overlapping) area. That is, the sum of Lc and Ld should be greater than the width of the second side 11225 of the electrode assembly 1122.

[0136] It should be noted that the stacking order of the two stacked second side films 11234 can be arbitrary. That is, the second side film 11234 with the first width can be located on the bottom layer to adhere to the second side 11225 of the electrode assembly 1122, and the second side film 11234 with the second width can be located on the outer layer to adhere to the second side film 11234 with the first width; or, the bonding order can be reversed, that is, the second side film 11234 with the second width can be located on the bottom layer to adhere to the second side 11225 of the electrode assembly 1122, and the second side film 11234 with the first width can be located on the outer layer to adhere to the second side film 11234 with the second width.

[0137] By stacking the two second-side membranes 11234 and forming at least an overlapping area, gaps at the connection points are reduced, improving the reliability of the insulation seal. Making the second width smaller than the first width reduces the risk of interference at the edges of the two second-side membranes 11234 during stacking and also helps save material.

[0138] In some embodiments, refer to Figure 5 and Figure 6 As shown, the first bottom film 11235 in one side composite film 11232 has a third width, and the first bottom film 11235 in the other side composite film 11232 has a fourth width. The fourth width is less than the third width, and the sum of the third width and the fourth width is greater than the width of the bottom surface 11226.

[0139] Specifically, the width of the first base film 11235 should be understood as the width of the first base film 11235 extending in a direction perpendicular to and away from the first side film 11233, for example, referring to Figure 5 and Figure 6 As shown, in the flat sheet state, the insulating film 1123 has a first bottom film 11235 disposed on the side of the first side film 11233 away from the top film 11231 along the third direction Z. The width of the first bottom film 11235 refers to the distance between the two side edges of the first bottom film 11235 along the third direction Z.

[0140] For example, in one side-mounted composite membrane 11232, there is a first bottom membrane 11235 with a width of Le, i.e., the third width is Le; in another side-mounted composite membrane 11232, there is a first bottom membrane 11235 with a width of Lf, i.e., the fourth width is Lf. Then, the fourth width is made smaller than the third width.

[0141] Typically, the third width is equal to the width of the bottom surface 11226 of the electrode assembly 1122, so that the first bottom film 11235, when attached to the bottom surface 11226, can cover the entire bottom surface 11226. Of course, the third width can also be less than the width of the bottom surface 11226 of the electrode assembly 1122, but the two stacked first bottom films 11235 should have at least an overlapping (or overlapping) area, that is, the sum of Le and Lf should be greater than the width of the bottom surface 11226 of the electrode assembly 1122.

[0142] It should be noted that the stacking order of the two stacked first base films 11235 can be arbitrary. That is, the first base film 11235 with a third width can be located at the bottom layer to adhere to the bottom surface 11226 of the electrode assembly 1122, and the first base film 11235 with a fourth width can be located at the outer layer to adhere to the first base film 11235 with a third width; or, the bonding order can be reversed, that is, the first base film 11235 with a fourth width can be located at the bottom layer to adhere to the bottom surface 11226 of the electrode assembly 1122, and the first base film 11235 with a third width can be located at the outer layer to adhere to the first base film 11235 with a fourth width.

[0143] By stacking the two first base films 11235 and forming at least an overlapping area, gaps at the connection points are reduced, improving the reliability of the insulation seal. Making the fourth width smaller than the third width reduces the risk of interference at the edges of the two first base films 11235 during stacking and also helps save material.

[0144] In this embodiment, by controlling the widths of the two overlapping second side films 11234 and the two overlapping first bottom films 11235, it is possible to save materials, reduce the risk of interference between the overlapping film layers, and improve the reliability of the overlapping seal.

[0145] In some embodiments, refer to Figure 5 and Figure 6 As shown, the second width Ld is 0.25 to 0.75 times the first width Lc.

[0146] Typically, the first width Lc is equal to the width of the second side film 11234. Therefore, the second width Ld is typically 0.25 to 0.75 times the first width Lc, and can take any value between 0.25 and 0.75. For example, the second width Ld is 0.5 times the first width Lc. Of course, the sum of Lc and Ld should be greater than the width of the second side surface 11225 of the electrode assembly 1122.

[0147] By controlling the width of the two second-side membranes 11234, the width and area of ​​the stacked region of the two second-side membranes 11234 can be controlled, which can save materials, reduce the risk of interference between the stacked membrane layers, and improve the reliability of the stacked seal.

[0148] In some embodiments, refer to Figure 5 and Figure 6 As shown, the fourth width Lf is 0.25 to 1.0 times the third width Le.

[0149] Typically, the third width Le is equal to the width of the first base film 11235. Therefore, the fourth width Lf is typically 0.25 to 1.0 times the third width Le, and can take any value between 0.25 and 1.0. For example, the fourth width Lf is 0.5 times the third width Le. Of course, the sum of Le and Lf should be greater than the width of the bottom surface 11226 of the electrode assembly 1122.

[0150] By controlling the width of the two first base films 11235, the width and area of ​​the stacked region of the two first base films 11235 can be controlled, which can save materials, reduce the risk of interference between the stacked film layers, and improve the reliability of the stacked seal.

[0151] In this embodiment, by controlling the width of the two overlapping film layers, it is possible to protect the surface of the electrode assembly 1122 while also saving the amount of material used in the insulating film 1123 and improving the reliability of sealing and insulation.

[0152] In some embodiments, refer to Figure 5 and Figure 6 As shown, the second bottom membrane 11236 has a preset width, which is less than or equal to the width of the second side membrane 11234 that is matched and connected to it.

[0153] Specifically, taking the example of each side-mounted composite film 11232 having two second bottom films 11236 as an example, the preset width refers to the width of any second bottom film 11236 in the two side-mounted composite films 11232. The width should be understood as the width of the insulating film 1123 extending along the first direction X in the sheet state. For example, refer to... Figure 6As shown, the width (first width) of the second side film 11234 in a side-combined film 11232 is Lc. Then, the width of the two second bottom films 11236 connected to the second side film 11234 is the fifth width Lg. This fifth width should be understood as the width of the insulating film 1123 in its sheet state extending along the first direction X, such that Lg ≤ Lc. When Lg < Lc, it is known that the second bottom film 11236 will have a gap with the first bottom film 11235 in the first direction X, thereby reducing the risk of interference during the folding process of the first bottom film 11235 and the second bottom film 11236. Typically, the second bottom film 11236 needs to have a gap space with the first bottom film 11235 to reduce interference during the folding process. Therefore, when Lg = Lc, the length of the first bottom film 11235 in the first direction X should be shortened to ensure the existence of the gap space.

[0154] Furthermore, if the width (second width) of the second side membrane 11234 in the other side composite membrane 11232 is Ld, then the width of the two second bottom membranes 11236 connected to the second side membrane 11234 is the sixth width Lm, such that Lm ≤ Ld. When Lm < Ld, it is known that the second bottom membrane 11236 will have a gap with the first bottom membrane 11235 in the first direction X, thereby reducing the risk of interference during the folding process of the first bottom membrane 11235 and the second bottom membrane 11236. It should be noted that since the first width and the second width can be the same or different, the fifth width and the sixth width can also be the same or different.

[0155] It should be noted that both the fifth and sixth widths should be smaller than the width of the bottom surface 11226 of the electrode assembly 1122, so that when the second bottom film 11236 is attached to the bottom surface 11226, the second bottom film 11236 will not protrude outward from the edge of the bottom surface 11226, thus ensuring the neatness of the film application.

[0156] In this embodiment, by making the width of the second bottom film 11236 less than or equal to the corresponding second side film 11234, it is easier to stack the first bottom film 11235 and the second bottom film 11236, reducing the risk of interference, thereby improving the regularity of the insulating film 1123 sheet and making it easier to prepare.

[0157] In some embodiments, refer to Figure 5 and Figure 6 As shown, the second bottom film 11236 has a preset length, which is equal to the size of the first bottom film 11235 that it matches.

[0158] Specifically, taking the example of each side-combination film 11232 having two second bottom films 11236, the preset length refers to the length of any second bottom film 11236 in the two side-combination films 11232. The length should be understood as the dimension of the insulating film 1123 in the sheet state, extending along the third direction Z. For example, if the width (third width) of the first bottom film 11235 in a side-combination film 11232 is Le, then the length of the two second bottom films 11236 opposite to the first bottom film 11235 is the first length Lp. The first length should be understood as the length of the insulating film 1123 in the sheet state, extending along the third direction Z, such that Lp = Le, thereby making the width of the first bottom film 11235 the same as the length of its corresponding second bottom film 11236, which makes it easier to cut the first bottom film 11235 and the second bottom film 11236 into shape.

[0159] Furthermore, in another side-mounted composite film 11232, the width (fourth width) of the first bottom film 11235 is Lf. Therefore, the length of the two second bottom films 11236 opposite to the first bottom film 11235 is the second length Lq. This second length should be understood as the length of the insulating film 1123 extending along the third direction Z in its sheet state, such that Lq = Lf. This ensures that the width of the first bottom film 11235 is the same as the length of its corresponding second bottom film 11236, making it easier to cut and shape the first bottom film 11235 and the second bottom film 11236. It should be noted that since the third and fourth widths can be the same or different, the first and second lengths can also be the same or different.

[0160] In this embodiment, by matching the length of the second bottom film 11236 to the width of the corresponding first bottom film 11235, the regularity of the insulating film 1123 sheet is improved, and it is also easier to prepare.

[0161] Of course, the preset length of the second bottom film 11236 can also be greater than or less than the width of the matching first bottom film 11235. The larger the preset length of the second bottom film 11236, the greater the extension length of the second bottom film 11236 on the bottom surface 11226 of the electrode assembly 1122, and the larger the coverage area. The preset length of one second bottom film 11236 should be less than or equal to the length of the bottom surface 11226 of the electrode assembly 1122 (i.e., the length of the bottom surface 11226 between the two second side surfaces 11225). When the sum of the preset lengths of the two opposite second bottom films 11236 in the first direction X is greater than the length of the bottom surface 11226 of the electrode assembly 1122, the two second bottom films 11236 will overlap each other, thereby further increasing the film thickness on the bottom surface 11226 and achieving the effect of raising the bottom surface 11226 of the electrode assembly 1122.

[0162] In some embodiments, refer to Figure 4 , Figure 5 and Figure 8 As shown, the electrode assembly 11221 has tabs 11222; the electrode assembly 1122 also includes an adapter (not shown in the figure), and the battery cell 1120 also includes an electrode terminal 1124 and an explosion-proof valve 1125. The electrode assembly 11221 and the adapter are both disposed in the receiving cavity 11213; the tabs 11222 on the electrode assembly 11221 are all electrically connected to the electrode terminal 1124 through the adapter, and the electrode terminal 1124 and the explosion-proof valve 1125 are both connected to the housing 1121; the top membrane 11231 covers the tabs 11222; the top membrane 11231 has a first clearance hole 11237 and a second clearance hole 11238, the explosion-proof valve 1125 is disposed opposite to the first clearance hole 11237, and the connection position of the adapter and the electrode terminal 1124 is disposed opposite to the second clearance hole 11238.

[0163] Specifically, an explosion-proof valve 1125 is typically installed on the housing 1121 to open and release gas in the event of thermal runaway of the battery cell 1120. Generally, the explosion-proof valve 1125 is mounted on the cover assembly 11211. The explosion-proof valve 1125 is positioned opposite to the top surface 11223 of the top membrane 11231 and the electrode assembly 1122. A first clearance hole 11237 is provided on the top membrane 11231 to correspond to the explosion-proof valve 1125, so that the gas generated by the electrode assembly 11221 can be connected to the explosion-proof valve 1125 through the first clearance hole 11237. The shape of the first clearance hole 11237 is consistent with the outline of the explosion-proof valve 1125 (such as circular, elliptical, etc.). The size of the first clearance hole 11237 is slightly larger than the outer dimensions of the explosion-proof valve 1125, ensuring that the explosion-proof valve 1125 can open smoothly when triggered, without being blocked or restricted by the top membrane 11231.

[0164] Since the adapter needs to be welded to the electrode terminal 1124 after being welded to the tab 11222, a second clearance hole 11238 needs to be reserved on the top film 11231. This second clearance hole 11238 corresponds to a portion of the adapter, specifically the welding position between the adapter and the electrode terminal 1124. Multiple second clearance holes 11238 can be provided, the number of which is the same as the number of welding positions between the adapter and the electrode terminal 1124. The shape of the second clearance hole 11238 is adapted to the welding area of ​​the adapter (e.g., rectangular, circular, etc.). The size of the second clearance hole 11238 covers at least a portion of the adapter and precisely corresponds to the laser welding position of the adapter, ensuring that the laser welding head can pass through the clearance hole and contact the adapter to complete the welding operation without interfering with the top film 11231.

[0165] The edges of the first clearance hole 11237 and the second clearance hole 11238 are both designed with rounded corners to reduce the risk of sharp edges scratching the electrode assembly 1122 or the related components of the cover assembly 11211, while improving the structural stability of the top film 11231 and preventing stress concentration from causing cracks.

[0166] In this example, the electrode assembly 1122, which includes two electrode components 11221, is used as an example for illustration. During assembly, the cover assembly 11211 is independently loaded to a preset station to ensure that the explosion-proof valve 1125 on the cover assembly 11211 is in the preset assembly posture (and the positioning structure of the lower plastic 11215 is in the preset assembly posture). Then, the insulating film 1123 is independently placed on the cover assembly 11211, so that the top film 11231 is positioned between the cover assembly 11211 and the cover assembly 11211 (for example, the insulating film 1123 is positioned by the snap-fit ​​between the first side film 11233 and the lower plastic 11215 on the cover assembly 11211). At this time, the first clearance hole 11237 on the top film 11231 is precisely aligned with the explosion-proof valve 1125 of the cover assembly 11211, ensuring that the explosion-proof valve 1125 is completely within the coverage area of ​​the first clearance hole 11237. Then, the ultrasonic waves are completed. The welded electrode assembly 1122 is placed on the top film 11231 and the first side film 11233 of the insulating film 1123. The position of the electrode assembly 1122 is adjusted so that the adapters (e.g., positive and negative adapters) on the top surface 11223 are precisely embedded in the second clearance holes 11238 of the corresponding adapters on the top film 11231. The welding area of ​​the adapters is completely exposed in the second clearance holes 11238. The rest of the top film 11231 is tightly attached to the top surface 11223 of the electrode assembly 1122 (e.g., tabs 11222). Then, the electrode assembly 11221 is wrapped with the first side film 11233, the bottom film, the second side film 11234, and the second bottom film 11236 is bent and wrapped in sequence. The second bottom film 11236 can also be glued and tightened to finally complete the overall wrapping and fixing of the insulating film 1123.

[0167] The top membrane 11231, as the core structure at the top of the insulating membrane 1123, needs to fit tightly with both the top surface 11223 of the electrode assembly 1122 and the inner side of the cover assembly 11211. This ensures both insulation protection and prevents coverage failure due to structural misalignment. The first clearance hole 11237 and the second clearance hole 11238 of the top membrane 11231 are provided for the functional areas of the explosion-proof valve 1125 and the adapter. The remaining areas are still tightly fitted with the top surface 11223 of the electrode assembly 1122 and the inner side of the cover assembly 11211, forming a continuous insulating protective surface. With the overall covering structure of the first side film 11233, the second side film 11234, and the bottom film of the insulating film 1123, the key insulation areas of the tab 11222 and the electrode assembly 1122 are completely covered, and there is no contact channel between them and the outer shell 1121 and the cover assembly 11211. At the same time, the size of the first clearance hole 11237 and the second clearance hole 11238 is strictly controlled, exposing only the functional parts of the explosion-proof valve 1125 and the adapter, without adding any additional insulation protection blind spots, thus reducing the risk of short circuits caused by improper opening of the clearance holes.

[0168] In this embodiment, by opening the first clearance hole 11237 and the second clearance hole 11238, the safe pressure relief function of the explosion-proof valve 1125 and the welding quality of the adapter can be maintained without affecting the circuit connection problem and venting problem of the battery caused by the interference of the insulating film 1123.

[0169] In some embodiments, refer to Figure 4 , Figure 5 and Figure 8 As shown, the top membrane 11231 and the cover assembly 11211 are disposed opposite to each other. The top membrane 11231 has a first positioning structure 11239, and the cover assembly 11211 has a second positioning structure 11216. Along the second direction Y, the first positioning structure 11239 and the second positioning structure 11216 are inserted and engaged. The second direction Y is perpendicular to the top membrane 11231.

[0170] Specifically, the shell body 11212 can be an aluminum square cylindrical structure with one end open and the other end closed, forming an accommodating cavity 11213 inside for accommodating the electrode assembly 1122, and the bottom edge corner of the closed end of the shell body 11212 is provided with an arc-shaped chamfer 11227.

[0171] During the process of covering the insulating film 1123, the top film 11231 needs to be positioned with the cover assembly 11211 at a preset station (or film covering station). The top film 11231 is provided with a first positioning structure 11239. The first positioning structure 11239 can be a protruding structure, then correspondingly, the second positioning structure 11216 is a hole structure; or, the first positioning structure 11239 can also be a hole structure, then correspondingly, the second positioning structure 11216 is a protruding structure.

[0172] The following explanation uses the first positioning structure 11239 as an example of a protruding structure. The first positioning structure 11239 can be a protruding insert along the thickness direction of the top film 11231 (i.e., the second direction Y, perpendicular to the plane where the top film 11231 is located). The insert is integrally formed with the top film 11231 and uses the same insulating polymer material as the top film 11231. Two inserts can be provided, symmetrically distributed on both sides of the length direction (i.e., the first direction) of the top film 11231.

[0173] The cover assembly 11211 is provided with a second positioning structure 11216, specifically an insertion hole adapted to the first positioning structure 11239. The insertion hole is along the second direction Y, and its diameter precisely matches the size of the insertion piece, while its depth matches the height of the insertion piece, ensuring that the insertion piece can be fully embedded in the insertion hole to form a tight insertion fit. The position of the second positioning structure 11216 corresponds one-to-one with the position of the first positioning structure 11239. When the top film 11231 is positioned opposite the cover assembly 11211, the insertion piece can be precisely aligned with the insertion hole along the second direction Y. The top film 11231 achieves precise positioning of the top film 11231 and the cover assembly 11211 through the insertion fit between the first positioning structure 11239 (insertion piece) and the second positioning structure 11216 (insertion hole) of the cover assembly 11211 along the second direction Y.

[0174] During assembly, the top film 11231 of the insulating film 1123 is placed inside the cover assembly 11211. The position of the insulating film 1123 is adjusted so that the first positioning structure 11239 (plug piece) on the top film 11231 is aligned with the second positioning structure 11216 (plug hole) of the cover assembly 11211 along the second direction Y (perpendicular to the top film 11231). The top film 11231 is pressed down so that the plug piece is fully embedded in the plug hole to form a plug-in fit. At this time, the clearance hole of the explosion-proof valve 1125 and the clearance hole of the adapter on the top film 11231 are precisely aligned with the welding areas of the explosion-proof valve 1125 and the adapter of the cover assembly 11211, respectively.

[0175] In related technologies, when the insulating film 1123 is integrated with the cover assembly 11211, positioning is achieved by relying on the integrated structure, but there is a problem of inconvenience in material packaging. If the materials are fed separately, the positioning stability is insufficient, and the insulating film 1123 is easily displaced in the direction parallel to the top film 11231 due to actions such as core joining and bending during the assembly process. This can cause the clearance hole to be misaligned with the explosion-proof valve 1125 and the adapter, affecting the realization of functions, or causing deviations in the covering positions of the side film and bottom film, resulting in insulation blind spots. In this embodiment, the first positioning structure 11239 and the second positioning structure 11216 are inserted and engaged along the second direction Y (perpendicular to the top membrane 11231) to form a positioning constraint in the vertical direction, and the third positioning structure 11240 and the fourth positioning structure 11217 are inserted and engaged to form a positioning constraint, thereby reducing the risk of displacement between the top membrane 11231 and the cover assembly 11211; at the same time, the insertion engagement is a rigid positioning with high engagement accuracy, which can ensure that the clearance hole of the top membrane 11231 is always precisely aligned with the explosion-proof valve 1125 and the adapter, so that the covering position of the side membrane and the bottom membrane always meets the design requirements, reducing the risk of displacement and misalignment (it can also be used in conjunction with the snap-fit ​​positioning of the second side membrane 11234).

[0176] This embodiment maintains the design of independent material supply and separate stacking of the insulating film 1123 and the cover assembly 11211, solving the packaging and material handling problems of integrated material supply. At the same time, the insertion and engagement of the first positioning structure 11239 and the second positioning structure 11216 has a guiding function. When the automated equipment places the insulating film 1123, it can quickly align the insertion piece with the insertion hole through visual positioning or mechanical guidance, without the need for complicated calibration procedures. Moreover, the positioning stability after insertion and engagement is strong, and there is no need to adjust the position of the insulating film 1123 in subsequent assembly processes, reducing assembly time. In addition, the separately stacked insulating film 1123 and cover assembly 11211 can achieve batch feeding, reduce the frequency of material change, and improve the continuity of automated production.

[0177] In this embodiment, by setting the first positioning structure 11239 and the second positioning structure 11216, the assembly positioning accuracy of the insulating film (Mylar film) can be improved, ensuring the normal realization of core functions such as the opening of the explosion-proof valve 1125 and the welding of the adapter, reducing the risk of insulation failure caused by the displacement of the insulating film 1123, and improving the battery assembly quality.

[0178] In some embodiments, refer to Figure 4 , Figure 5 and Figure 8As shown, the cover assembly 11211 includes a cover 11214 and a lower plastic 11215. The cover 11214 and the shell body 11212 together form an accommodating cavity 11213. The lower plastic 11215 is connected to the cover 11214 and disposed on the side of the cover 11214 facing the accommodating cavity 11213. The second positioning structure 11216 is disposed on the lower plastic 11215.

[0179] Specifically, the cover assembly 11211 has a modular structure, including a cover 11214 (top cover) and a lower plastic 11215. The cover 11214 is made of metal (such as aluminum alloy) and is used to seal the opening end of the shell body 11212. The lower plastic 11215 is made of insulating polymer material. The lower plastic 11215 can be fixed to the side (inner side) of the cover 11214 facing the receiving cavity 11213 by injection molding or snap-fit ​​connection. The lower plastic 11215 extends along the length of the cover 11214 and covers the middle area of ​​the inner side of the cover 11214, which not only serves as insulation and isolation but also provides a positioning reference for the insulating film 1123.

[0180] The second positioning structure 11216 is disposed on the lower plastic 11215. For example, the second positioning structure 11216 is an insertion hole adapted to the first positioning structure 11239 (insertion piece) of the top film 11231. The insertion hole penetrates the lower plastic 11215 along the second direction Y (perpendicular to the top film 11231). Its number and position correspond one-to-one with the first positioning structure 11239. The hole diameter is precisely matched with the size of the insertion piece to ensure that the two form a tight insertion fit.

[0181] The two sides of the lower plastic 11215 form a snap-fit ​​area that adapts to the second side film 11234. The inner edge of the second side film 11234 is attached to the outer side wall of the lower plastic 11215. The snap-fit ​​action restricts the lateral displacement of the second side film 11234. It forms a dual positioning system with the insertion and cooperation of the "first positioning structure 11239 and the second positioning structure 11216".

[0182] When the insulating film 1123 is assembled with the cover assembly 11211, the first positioning structure 11239 of the top film 11231 is inserted into the second positioning structure 11216 of the lower plastic 11215 along the second direction Y, while the second side film 11234 is stuck on both sides of the lower plastic 11215, so as to achieve precise and stable positioning of the insulating film 1123 and the cover assembly 11211, and ensure that the insulating film 1123 does not shift during subsequent assembly.

[0183] During the loading process of the cover assembly 11211, the pre-assembled cover assembly 11211 (the cover 11214 and the lower plastic 11215 are fixedly connected) is loaded independently, so that the inner side of the cover assembly 11211 (the side where the lower plastic 11215 is located) faces upward, ensuring that the second positioning structure 11216 (plug hole) on the lower plastic 11215 is in a position that facilitates docking; the insulating film 1123 is placed independently inside the cover assembly 11211, and the position of the insulating film 1123 is adjusted so that the first positioning structure 11239 (plug piece) on the top film 11231 is aligned with the second positioning structure 11216 (plug hole) on the lower plastic 11215 along the second direction Y, and the insulating film 1123 is pressed down so that the plug piece is fully embedded in the plug hole to form a rigid plug-in fit.

[0184] The lower plastic 11215 serves as the core insulating component of the cover assembly 11211, primarily used to isolate the cover 11214 from the electrode assembly 1122. In this embodiment, the second positioning structure 11216 is directly disposed on the lower plastic 11215, making full use of the structural space and insulating properties of the lower plastic 11215. On one hand, the lower plastic 11215 is fixedly connected to the cover 11214, exhibiting strong structural stability. As a positioning carrier, it can ensure the positional accuracy of the second positioning structure 11216, thereby improving the matching accuracy with the first positioning structure 11239. On the other hand, the lower plastic 11215 itself is an insulating material, and its positioning and matching with the insulating film 1123 (an insulating material) will not introduce the risk of electrical conductivity, reducing the potential short circuit hazard that may be caused by the metal positioning structure.

[0185] If the second positioning structure 11216 is set on the cover 11214 (metal material), additional insulation treatment is required (such as embedding an insulating sleeve, coating treatment, etc.), which will increase the processing steps and costs; however, if the second positioning structure 11216 is set on the lower plastic 11215, it can be directly processed and formed by injection molding without affecting the original insulation function of the lower plastic 11215, without the need for additional processing steps or parts.

[0186] In this embodiment, by setting the lower plastic 11215 and placing the second positioning structure 11216 on the lower plastic 11215, the battery's insulation safety performance is enhanced while ensuring positioning accuracy. This reduces the risk of short circuits caused by improper material or unreasonable layout of the positioning structure, and improves the stability of assembly quality. It also improves the long-term stability and anti-aging performance of the battery cell 1120, extends the service life of the battery cell 1120, and enhances the reliability of the battery cell 1120 under complex operating conditions.

[0187] In some embodiments, refer to Figure 4 , Figure 5 and Figure 8As shown, the cover assembly 11211 includes a cover 11214 and a lower plastic 11215. The cover 11214 and the shell body 11212 together form an accommodating cavity 11213. The lower plastic 11215 is connected to the cover 11214 and is disposed on the side of the cover 11214 facing the accommodating cavity 11213. The fourth positioning structure 11217 is disposed on the cover 11214.

[0188] Specifically, the structure of the cover assembly 11211 can be referred to in the above embodiments, and will not be repeated here.

[0189] The fourth positioning structure 11217 is disposed on the cover 11214. For example, the fourth positioning structure 11217 is an insertion hole adapted to the third positioning structure 11240 (insertion protrusion) on the first side film 11233. The insertion hole is formed along the second direction Y (perpendicular to the top film 11231) near the edge of the cover 11214 and can avoid the lower plastic 11215. Its number and position correspond one-to-one with the third positioning structure 11240. The diameter of the insertion hole is precisely matched with the size of the insertion protrusion to ensure that the two form a tight insertion fit.

[0190] The two sides of the lower plastic 11215 can form a snap-fit ​​area that fits the second side film 11234. The inner edge of the second side film 11234 is attached to the outer side wall of the lower plastic 11215. The snap-fit ​​action restricts the lateral displacement of the second side film 11234. It forms a dual positioning system with the insertion and cooperation of the "first positioning structure 11239 and the second positioning structure 11216".

[0191] During the loading process of the cover assembly 11211, the pre-assembled cover assembly 11211 (the cover 11214 and the lower plastic 11215 are fixedly connected) is loaded independently, so that the inner side of the cover assembly 11211 (the side where the lower plastic 11215 is located) faces upward, ensuring that the fourth positioning structure 11217 (insertion hole) on the cover 11214 is in a position that facilitates docking; the insulating film 1123 is placed independently on the inner side of the cover assembly 11211, and the position of the insulating film 1123 is adjusted so that the first positioning structure 11239 (insertion piece) on the top film 11231 is aligned with the second positioning structure 11216 (insertion hole) on the lower plastic 11215 along the second direction Y, and the third positioning structure 11240 on the first side film 11233 is aligned with the fourth positioning structure 11217 on the cover 11214 along the second direction Y, forming a rigid insertion fit.

[0192] The lower plastic 11215 serves as the core insulating component of the cover assembly 11211, primarily used to isolate the cover 11214 from the electrode assembly 1122. The fourth positioning structure 11217 can be disposed on one side of the lower plastic 11215, and the side of the lower plastic 11215 can serve as a guide plane. The fourth positioning structure 11217 can fit against this guide plane and be inserted into the third positioning structure 11240, resulting in strong structural stability. As a positioning carrier, it can ensure the positional accuracy of the fourth positioning structure 11217, which is beneficial to improving the matching accuracy between the fourth positioning structure 11217 and the third positioning structure 11240. On the other hand, the lower plastic 11215 itself is an insulating material, and its positioning and matching with the insulating film 1123 (an insulating material) will not introduce the risk of electrical conductivity, reducing the potential short circuit hazard that may be caused by the metal positioning structure.

[0193] In this embodiment, by setting a cover 11214 and a lower plastic 11215, and placing the fourth positioning structure 11217 on the cover 11214, the battery's insulation safety performance is enhanced while ensuring positioning accuracy. This reduces the risk of short circuits caused by improper material or layout of the positioning structure, and improves the stability of assembly quality. It also improves the long-term stability and anti-aging performance of the battery cell 1120, extends its service life, and enhances its reliability under complex operating conditions.

[0194] In some embodiments, the cover assembly 11211 is also provided with a liquid injection hole, and the top membrane 11231 should be provided with at least a liquid injection hole opposite to it, so as to realize liquid injection flushing to prevent mistaken identity. During liquid injection, due to the importance of liquid injection efficiency, the liquid injection impact force is large, which poses a risk of flushing the separator membrane, causing the separator membrane to fold and the anode and cathode plates (positive electrode plate and negative electrode plate) to short-circuit. Therefore, the top membrane 11231 of the insulating membrane 1123 is shielded below the liquid injection hole, so that the insulating membrane 1123 protects the end face of the electrode terminal 1124 and reduces the risk of the separator membrane being flushed.

[0195] In some embodiments, refer to Figure 5 , Figures 8-11 and Figure 18 As shown, the cover assembly 11211 includes a cover 11214 and a lower plastic 11215. The cover 11214 and the shell body 11212 together form a receiving cavity 11213. The lower plastic 11215 is connected to the cover 11214 and disposed on the side of the cover 11214 facing the receiving cavity 11213. Along the first direction X, one or both ends of the lower plastic 11215 have positioning protrusions 11218. Corresponding to the positioning protrusions 11218, one or both ends of the top film 11231 have clearance areas 11242. The positioning protrusions 11218 are limited between the two first side films 11233 by the clearance areas 11242.

[0196] Specifically, the cover 11214, as the main structure of the cover assembly 11211, is made of a rigid material (preferably a metal material, such as aluminum alloy, stainless steel, or high-strength engineering plastic, such as ABS, PC material). Its shape is adapted to the opening shape of the shell body 11212 to ensure that the cover 11214 and the shell body 11212 can fit tightly after assembly.

[0197] The lower plastic 11215 is connected to the cover 11214 and is specifically located on the side of the cover 11214 facing the receiving cavity 11213, that is, the lower plastic 11215 is located between the cover 11214 and the receiving cavity 11213. The lower plastic 11215 is made of soft or semi-rigid plastic material (such as silicone, TPU, soft PVC, etc.), and its main function is to fill the gap between the cover 11214 and the internal components, playing a role in buffering, sealing and insulation, while reducing the risk of wear, short circuit and other problems caused by direct contact between the cover 11214 (especially the metal cover 11214) and the internal components.

[0198] The connection between the lower plastic 11215 and the cover 11214 can be achieved through methods such as integral injection molding, snap-fit ​​connection, bonding, or screw fixing. For example, integral injection molding is used, in which the corresponding part of the cover 11214 is embedded into the injection mold during the injection molding process of the lower plastic 11215, so that the lower plastic 11215 and the cover 11214 form a firm integral structure. This not only simplifies the assembly process, but also improves the sealing and stability of the connection between the two, and reduces the risk of separation between the lower plastic 11215 and the cover 11214 during use.

[0199] To achieve precise positioning and assembly of the cover assembly 11211 with the top membrane 11231 and the two first side membranes 11233 inside the device, a positioning protrusion 11218 is integrally formed at one or both ends of the lower plastic 11215 along the first direction X. The shape of the positioning protrusion 11218 can be a cuboid, a cylinder, or a frustum. Corresponding to the positioning protrusion 11218, a clearance area 11242 is provided at one or both ends of the top membrane 11231. The clearance area 11242 is the space formed by the edges of the two first side membranes 11233 and the edge of the top membrane 11231. The shape of the clearance area 11242 is adapted to the shape of the positioning protrusion 11218, and the size of the clearance area 11242 can be equal to or slightly larger than the size of the positioning protrusion 11218, so as to ensure that the positioning protrusion 11218 can pass smoothly through the clearance area 11242 and ensure the sealing or isolation effect between the positioning protrusion 11218 and the top membrane 11231.

[0200] When the cover assembly 11211 is assembled with the top membrane 11231 and the first side membrane 11233 (third positioning structure 11240), the positioning protrusion 11218 passes through the avoidance area 11242 on the top membrane 11231 and is confined within the positioning space between the two first side membranes 11233. The positioning space limits the two sides of the positioning protrusion 11218, thereby realizing the positioning of the cover assembly 11211 in the first direction X (horizontal direction) and reducing the risk of the cover assembly 11211 shifting or shaking after assembly.

[0201] In this embodiment, both ends of the lower plastic 11215 are provided with positioning protrusions 11218, and correspondingly, both ends of the top film 11231 are provided with avoidance areas 11242. After the two positioning protrusions 11218 pass through the corresponding avoidance areas 11242, they are limited to being located between the two first side films 11233. This double-sided positioning structure can further improve the stability of the assembly of the cover assembly 11211, ensure the fitting accuracy of the cover 11214 and the shell body 11212, and reduce the problem of assembly offset.

[0202] According to some embodiments of this application, refer to Figure 1 As shown, this application also provides a battery device 1100, which includes the battery cells 1120 in the above embodiments. The battery device 1100 (Battery Apparatus) may include one or more battery cell assemblies for providing voltage and capacity. The battery cell assembly may include multiple battery cells 1120, which are connected in series, parallel, or mixed connection via a busbar. The battery device 1100 may be a battery pack, which generally includes a housing 1110 and one or more battery cell assemblies, with the battery cell assemblies housed within the housing 1110.

[0203] In some embodiments, reference is made to Figure 2As shown, the housing 1110 may include a first part 1111 and a second part 1112, which overlap each other, defining a space for accommodating the battery cell 1120. The second part 1112 may be a hollow structure with one open end, while the first part 1111 may be a plate-like structure, covering the open side of the second part 1112 so that the first part 1111 and the second part 1112 together define an accommodating space 1113. Alternatively, both the first part 1111 and the second part 1112 may be hollow structures with one open side, with the open side of the first part 1111 covering the open side of the second part 1112. Of course, the housing 1110 formed by the first part 1111 and the second part 1112 can be of various shapes, such as a cylinder or a cuboid.

[0204] For details, please refer to the description of the above embodiments, which will not be repeated here.

[0205] According to some embodiments of this application, refer to Figure 1 As shown, this application also provides an electrical device, which includes the battery cell 1120 in the above embodiments; or, the electrical device includes the battery device 1100 in the above embodiments, which is used to store or provide electrical energy.

[0206] Specifically, refer to Figure 2 As shown in the illustration, this application provides a battery device 1100. The battery device 1100 disclosed in this application can be used in electrical devices that use the battery device 1100 as a power source or in various energy storage devices and systems that use the battery device 1100 as an energy storage element. Electrical devices can be, but are not limited to, mobile phones, portable devices, laptops, electric toys, power tools, electric vehicles, vehicles 1000, ships, spacecraft, etc. Electric toys can include stationary or mobile electric toys, such as game consoles, electric car toys, electric boat toys, and electric airplane toys, etc. Spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.

[0207] For ease of explanation, the following embodiments will be described using a vehicle 1000 as an example of an electrical device according to an embodiment of this application.

[0208] 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 1100 is provided inside the vehicle 1000, and the battery device 1100 can be located at the bottom, front, or rear of the vehicle 1000. The battery device 1100 can be used to power the vehicle 1000; for example, the battery device 1100 can serve as the operating power source for the vehicle 1000. The vehicle 1000 may also include a controller 1200 and a motor 1300. The controller 1200 is used to control the battery device 1100 to supply power to the motor 1300, for example, to meet the power needs of the vehicle 1000 during starting, navigation, and driving.

[0209] In some embodiments of this application, the battery device 1100 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.

[0210] The examples of electrical devices in this application are based on the examples of the battery device 1100 described above. The examples of electrical devices include all the technical effects of the examples of the battery device 1100 described above, and will not be repeated here.

[0211] According to some embodiments of this application, refer to Figure 12-17 As shown, this application also provides a method for preparing a battery cell 1120, the method including the steps of prefabricating an insulating film 1123, prefabricating an electrode assembly 1122, covering the electrode assembly 1122 with the insulating film 1123, welding electrode terminals 1124, and inserting the battery into a casing.

[0212] Specifically, in step S01, referring to Figure 5 and Figure 12 As shown, a sheet of insulating film 1123 in the battery cell 1120 of the above embodiment is prefabricated.

[0213] The insulating film 1123 mentioned above is the same as the insulating film 1123 in the example above. Before being wrapped, the insulating film 1123 is a sheet material. The sheet material of the insulating film 1123 includes a top film 11231 and two side combination films 11232. Each side combination film 11232 includes a first side film 11233, a first bottom film 11235, and two second side films 11234. The top film 11231, the first side film 11233, the second side film 11234, the first bottom film 11235, and the second side film 11234 are all on the same plane to form the sheet material of the insulating film 1123. In the third direction Z, two side-combination membranes 11232 are located on both sides of the top membrane 11231, and the top membrane 11231 is connected to the first side membrane 11233 on both sides. The first bottom membrane 11235 is connected to the side of the first side membrane 11233 away from the top membrane 11231 (the first bottom membrane 11235 is opposite to the top membrane 11231 and is located on both sides of the first side membrane 11233). In the first direction X, two second side membranes 11234 are connected to both sides of the first side membrane 11233. In the third direction Z, the second bottom membrane 11236 is connected to the side of the second side membrane 11234 closer to the first bottom membrane 11235. In the first direction X, the second bottom membrane 11236 is located on one or both sides of the first bottom membrane 11235 (when one side-combination membrane 11232 is provided with two second bottom membranes 11236).

[0214] In step S02, refer to Figure 13 As shown, prefabricated electrode assembly 1122.

[0215] The electrode assembly 1122 may include one or more electrode components 11221. The electrode components 11221 may be prepared by winding or stacking. When the electrode assembly 1122 includes multiple electrode components 11221, the multiple electrode components 11221 may be electrically connected to each other through an adapter.

[0216] In step S03, refer to Figure 13-17 As shown, the insulating film 1123 covers the electrode assembly 1122. Specifically, firstly, the cover assembly 11211 and the electrode assembly 1122 are fed separately. Then, the insulating film 1123 (e.g., the top film 11231 or the first side film 11233) is initially positioned with the electrode assembly 1122, so that the third positioning structure 11240 and the fourth positioning structure 11217 are inserted and positioned. Then, the films of each part are wrapped in sequence.

[0217] Specifically, in step S031, referring to Figure 13As shown, at the preset work station, the cover assembly 11211, insulating film 1123 and electrode assembly 1122 of the outer shell 1121 are placed separately using the individual feeding method. The insulating film 1123 is in an unfolded sheet state, which allows the top film 11231 in the insulating film 1123 to be paired with the inner side of the cover assembly 11211.

[0218] The known outer shell 1121 includes a cover assembly 11211 and a shell body 11212. The cover assembly 11211 is attached to the shell body 11212 to jointly enclose and form an accommodating cavity 11213. The cover assembly 11211 may also include a cover 11214 and a lower plastic 11215. When assembling the insulating film 1123, the top film 11231 of the insulating film 1123 is first assembled with the cover assembly 11211. The cover assembly 11211 has an inner side, which can be understood as the side surface facing the shell body 11212 when the cover assembly 11211 is connected to the shell body 11212. The cover assembly 11211 is positioned at the bottom with its inner side facing upward at a preset station. Then, the insulating film 1123 is transported to the preset station, so that the top film 11231 of the insulating film 1123 is laid flat on the upper part of the cover assembly 11211, and the third positioning structure 11240 and the fourth positioning structure 11217 are inserted and positioned.

[0219] It should be noted that, taking the third positioning structure 11240 as a protruding sheet structure as an example, since the sheet-like third positioning structure 11240 and the first side film 11233 should be coplanar integral film structures, after the step of prefabricating the insulating film 1123 and before the step of assembling and positioning the top film 11231 with the cover assembly 11211, a step of bending the third positioning structure 11240 should also be included. That is, bending the sheet-like third positioning structure 11240. Structure 11240 is perpendicular to the first side membrane 11233. The third positioning structure 11240 can be bent at the position where it connects with the first side membrane 11233. That is, the protruding direction of the third positioning structure 11240 is perpendicular to the top membrane 11231. In this way, the third positioning structure 11240 can be inserted into the fourth positioning structure 11217 (groove structure) of the cover assembly 11211 along the second direction Y, thus completing the assembly and positioning of the top membrane 11231 and the cover assembly 11211.

[0220] Then, in step S032, the electrode assembly 1122 and the insulating film 1123 are assembled and positioned together, and the two first side films 11233 in the insulating film 1123 are respectively attached to the two first side films 11224 of the electrode assembly 1122.

[0221] Specifically, when an electrode assembly 11221 is provided, one of the first side films 11233 of the insulating film 1123 can be attached to one of the first side films 11224 of the electrode assembly 11221, and then the other first side film 11233 of the insulating film 1123 can be attached to the other first side film 11224 of the electrode assembly 11221. When an adapter is provided, both the tab 11222 and the adapter can be positioned and connected to the top film 11231 of the insulating film 1123 to achieve preliminary positioning of the insulating film 1123 and the electrode assembly 1122.

[0222] Then, in step S04, refer to Figure 15 and Figure 16 As shown, a first bottom film 11235, a second side film 11234, and a second bottom film 11236 are covered. When covering the first bottom film 11235 and the second side film 11234, there is no fixed order. The first bottom film 11235 can be covered first and then the second side film 11234 can be covered, or the second side film 11234 can be covered first and then the first bottom film 11235 can be covered. Then, the second bottom film 11236 can be covered.

[0223] Taking the first layer of the bottom film 11235 as an example, specifically, in step S041, during the step of covering the first bottom film 11235, the two first bottom films 11235 are folded in sequence so that the two first bottom films 11235 are attached to and stacked with the bottom surface 11226 of the electrode assembly 1122. The two first bottom films 11235 are cross-overlaid on the bottom surface 11226 to form an overlap area, thereby improving the sealing effect. In addition, since two layers of the first bottom film 11235 are stacked on the bottom surface 11226, the thickness of the film on the bottom surface 11226 can be increased. After the electrode assembly 1122 is installed in the outer shell 1121, the height of the bottom surface 11226 is raised so that the bottom corner 11228 of the electrode assembly 1122 is far away from the arc-shaped chamfer 11227 at the bottom of the outer shell 1121 (shell body 11212).

[0224] It should be noted that the first bottom film 11235 and the second bottom film 11236 are not connected and there is a gap between them. Therefore, when the first bottom film 11235 is folded, the second bottom film 11236 will not move and will not affect the position of the second bottom film 11236.

[0225] In step S042, during the step of covering the second side film 11234, the four second side films 11234 are folded toward the corresponding second side surface 11225 of the electrode assembly 1122, so that two second side films 11234 are attached and stacked on each second side surface 11225; correspondingly, the four second bottom films 11236 are stacked in pairs.

[0226] Specifically, since each side assembly membrane 11232 includes two second side membranes 11234, it can be known that there are two second side membranes 11234 on each second side surface 11225 of the electrode assembly 1122, and the two second side membranes 11234 are folded and attached to the second side surface 11225; the two second side membranes 11234 overlap on the second side surface 11225 to form an overlap area, thereby improving the sealing effect.

[0227] Since the second bottom film 11236 is connected to the second side film 11234, it is understandable that during the folding of the second side film 11234, the second bottom film 11236 will also fold, so that the two second bottom films 11236 located on one side of each second side 11225 will also be stacked, and the thickness of the composite stacked layer formed by the two second bottom films 11236 will double.

[0228] In step S043, during the step of covering the second bottom film 11236, refer to Figure 16 As shown, two second bottom films 11236 (i.e., composite stacked layers) that are stacked in pairs are folded toward the bottom surface 11226 of the electrode assembly 1122, so that the two stacked second bottom films 11236 (i.e., composite stacked layers) are respectively attached to and stacked with the first bottom film 11235.

[0229] Specifically, after the second side film 11234 is attached to the second side surface 11225, the two stacked second bottom films 11236 (composite stacked layers) will protrude from the bottom surface 11226 of the electrode assembly 1122. By folding the stacked second bottom films 11236 on both sides toward the bottom surface 11226, the second bottom films 11236 can be stacked on the first bottom film 11235. Therefore, it can be understood that the film structure attached to the bottom surface 11226 includes two first bottom films 11235 and two second bottom films 11236, making... The thickness of the film structure attached to the bottom surface 11226 is further increased, so that after the electrode assembly 1122 is installed in the housing 1121, the height of the bottom surface 11226 can be further raised, so that the bottom corner 11228 of the electrode assembly 1122 is far away from the arc chamfer 11227 at the bottom of the housing 1121 (the housing body 11212), thereby achieving the thickness of the bottom plate in the related art. The bottom plate is replaced by a film structure in which two first bottom films 11235 and two second bottom films 11236 are stacked.

[0230] In step S05, the electrode terminal 1124 is electrically connected and soldered to the electrode assembly 11221 (e.g., tab or adapter).

[0231] Specifically, the electrode terminal 1124 includes a positive electrode terminal 1124 and a negative electrode terminal 1124. The positive electrode terminal 1124 (e.g., through a positive electrode adapter) is electrically connected to the positive electrode tab, and the negative electrode terminal 1124 (e.g., through a negative electrode adapter) is electrically connected to the negative electrode tab. The electrical connection can be achieved by welding. For example, the electrode terminal 1124 and the adapter can be connected by laser welding.

[0232] Taking the case with an adapter as an example, it should be noted that the step of assembling the electrode terminal 1124 can be set in the step of prefabricating the cover assembly 11211. During the assembly of the cover assembly 11211, the electrode terminal 1124 can be installed on the cover assembly 11211. The step of electrically connecting the electrode terminal 1124 can be set after the step of covering the insulating film 1123 and before the step of inserting the shell; or, the step of electrically connecting the electrode terminal 1124 can also be set after the step of covering the insulating film 1123 and after the step of inserting the shell. All of the above methods are acceptable, and the appropriate method can be selected and adapted according to the specific scenario.

[0233] In step S06, the electrode assembly 1122 with the coating completed is inserted into the receiving cavity 11213 of the shell body 11212 of the outer shell 1121, so that the cover assembly 11211 and the shell body 11212 are sealed together.

[0234] Specifically, after the electrode assembly 1122 is covered with the insulating film 1123, it forms an integral structure with an external film. This integral structure can be installed into the receiving cavity 11213 of the shell body 11212, and the cover assembly 11211 can be placed on the opening of the receiving cavity 11213 to form a closed receiving cavity 11213. The cover assembly 11211 is fixedly connected to the shell body 11212. In this step, a liquid injection process can also be performed, injecting electrolyte into the receiving cavity 11213 through the liquid injection hole on the cover assembly 11211.

[0235] In this embodiment, by improving the insulating film 1123 in the battery cell 1120, a third positioning structure 11240 is provided on the first side film 11233 of the side combination film 11232, and a fourth positioning structure 11217 is correspondingly provided on the cover assembly 11211 of the outer casing 1121. During the assembly and positioning of the electrode assembly 1122, the side combination film 11232, and the outer casing 1121, the top film 11231 is positioned opposite to the cover assembly 11211, and the third positioning structure 11240 and the fourth positioning structure 11217 are positioned opposite each other. The insertion of 217 further improves the positioning reliability between the insulating film 1123 and the cover assembly 11211, reduces the risk of displacement of the insulating film 1123 relative to the cover assembly 11211, and achieves the initial positioning of the electrode assembly 1122, the side assembly film 11232, and the cover assembly 11211, making it less prone to offset and misalignment among the three, resulting in high positioning reliability. This improves the overall assembly quality of the battery cell 1120 and is beneficial to improving battery performance. In addition, the entire outer surface of the electrode assembly 1122 is covered by the insulating film 1123. Different parts of the electrode assembly 11221 are correspondingly bonded and wrapped, effectively insulating the electrode assembly 11221 from the side wall of the outer shell 1121 and from the outer shell, reducing the risk of short circuits. The overlapping wrapping method also increases the tightness and reliability of the wrapping, thereby improving the insulation reliability. Two layers of first bottom film 11235 and one or two layers of second bottom film 11236 are laminated on the bottom surface 11226 of the electrode assembly 1122, raising the height of the bottom surface 11226 of the electrode assembly 1122, thereby increasing the bottom corner 112 of the electrode assembly 1122. 28 can be kept away from and avoid the arc-shaped chamfer 11227 at the bottom of the outer casing 1121, reducing the risk of interference between the bottom corner 11228 and the arc-shaped chamfer 11227, reducing the risk of the electrode assembly 11221 being crushed and damaged, which is conducive to improving the service life and reliability of the electrode assembly 11221; in addition, the bottom of the electrode assembly 1122 does not need to be provided with a bottom support plate, eliminating the preparation and installation process of the bottom support plate, which is conducive to reducing the manufacturing cost of the battery cell 1120; eliminating the bottom support plate can also reduce the weight of the battery cell 1120, which is conducive to weight reduction.

[0236] In some embodiments, refer to Figure 13 As shown, the electrode assembly 1122 includes an adapter and at least two electrode assemblies 11221; in step S02, the step of prefabricating the electrode assembly 1122 includes connecting the tabs 11222 of at least two electrode assemblies 11221 to the adapter to form the electrode assembly 1122.

[0237] Specifically, a prefabricated adapter and multiple electrode assemblies 11221 are used to connect the tabs 11222 of the multiple electrode assemblies 11221 to the adapter to form an electrode assembly 1122.

[0238] The electrode assembly 11221 can be fabricated by winding or stacking. The adapter can be an adapter piece, and multiple adapters can be provided. Each electrode assembly 11221 has a positive electrode tab and a negative electrode tab. Therefore, the adapter includes a positive electrode adapter piece and a negative electrode adapter piece. The positive electrode tab is welded to the positive electrode adapter piece, and the negative electrode tab is welded to the negative electrode adapter piece, typically using ultrasonic welding. Multiple electrode assemblies 11221 can each have a set of positive and negative electrode tabs, or multiple electrode assemblies 11221 can share a positive electrode tab and a shared negative electrode tab. After welding the adapters to the tabs of multiple electrode assemblies 11221, an electrode assembly 1122 is formed. The entire electrode assembly 1122 is moved to a preset station to be covered with an insulating film 1123.

[0239] Taking a configuration with two electrode assemblies 11221 as an example, the positive tabs of the two electrode assemblies 11221 are electrically connected through a positive electrode adapter, and the negative tabs of the two electrode assemblies 11221 are electrically connected through a negative electrode adapter. Both electrode assemblies 11221 are in a flat state (i.e., on the same plane), and the two electrode assemblies 11221 are located on both sides of the adapter.

[0240] In step S03, the assembly and positioning of the electrode assembly 1122 and the insulating film 1123, with the two first side films 11233 of the insulating film 1123 respectively corresponding to the two first side films 11224 of the electrode assembly 1122, includes: at a preset station, positioning and connecting the tab 11222 and the adapter to the top film 11231 of the insulating film 1123, with the two first side films 11233 of the insulating film 1123 respectively corresponding to and fitting the two first side films 11224 of the outer electrode assembly 11221 in the electrode assembly 1122; and folding the core, stacking the electrode assembly 11221 so that the first side films 11224 of adjacent electrode assemblies 11221 are opposite or fitted together, maintaining the two first side films 11233 respectively corresponding to and fitting the two first side films 11224 of the outer electrode assembly 11221.

[0241] Specifically, in step S03, refer to Figure 12-17 As shown, the electrode assembly 1122 is assembled and positioned with the insulating film 1123, so that the tab 11222 and the adapter are positioned and connected with the top film 11231 of the insulating film 1123. The two first side films 11233 in the insulating film 1123 are respectively matched and attached to the two first side surfaces 11224 of the outer electrode assembly 11221 in the electrode assembly 1122.

[0242] It is known that both electrode assemblies 11221 are in a flat state, with tabs 11222 and adapters located between them. The tabs 11222 and adapters are aligned with their corresponding positions on the top membrane 11231 (e.g., the position of the adapter for welding to the electrode terminal 1124 corresponds to the second clearance hole 11238), thus achieving positioning and connection between the tabs 11222 and adapters and the top membrane 11231. During the positioning of the top membrane 11231, the first side 11224 of the two electrode assemblies 11221 facing the insulating membrane 1123 will correspondingly adhere to the two first side membranes 11233.

[0243] Reference Figure 14 As shown, then, the core is combined, and multiple electrode assemblies 11221 are folded to stack and arrange so that the first side surfaces 11224 of adjacent electrode assemblies 11221 are positioned opposite or in contact with each other, and the two first side films 11233 are respectively in contact with the two first side surfaces 11224 of the outer electrode assembly 11221.

[0244] Among them, the positions of the core-connecting top film 11231 and the cover assembly 11211 are fixed, and the two flat electrode assemblies 11221 are folded upward and brought closer together, so that the two first side surfaces 11224 of the two electrode assemblies 11221 that are close to each other (or located on the inside) are opposite or attached to each other, so that the two electrode assemblies 11221 are stacked and arranged.

[0245] During or after the electrode assembly 11221 is folded, the first side film 11233 adheres to the two outer (exposed) first side surfaces 11224 of the two stacked electrode assemblies 11221. In this state, the second side film 11234, the first bottom film 11235, and the second bottom film 11236 are all on the same plane as the first side film 11233 and all extend outward from the first side surface 11224.

[0246] In this embodiment, the electrode assembly 1122, which has multiple electrode components 11221, can be positioned and connected to the top film 11231 of the insulating film 1123 by positioning the tabs 11222 and the adapters. At the same time, the two first side films 11233 in the insulating film 1123 are respectively matched and attached to the two first side films 11224 of the outer electrode components 11221 in the electrode assembly 1122. Then, the core is closed, so that the entire outer surface of the electrode assembly 1122 is covered by different parts of the insulating film 1123. This effectively insulates the electrode components 11221 from the side walls of the outer shell 1121 and from the outer shell, reducing the risk of short circuit. The overlapping wrapping method also increases the tightness and reliability of the wrapping, thereby improving the insulation reliability.

[0247] In some embodiments, refer to Figure 17 As shown, after the step of covering the second bottom film 11236, adhesive is applied to the bottom surface 11226 and the portion of the second side surface 11225 of the electrode assembly 1122 near the bottom surface 11226, so that the adhesive 11241 at least covers the second bottom film 11236, at least a portion of the first bottom film 11235 and at least a portion of the second side film 11234.

[0248] Specifically, after the second bottom film 11236 is wrapped, the bottom film (first bottom film 11235, second bottom film 11236) and the side film (first side film 11233, second side film 11234) are in a tight fit without displacement, ensuring that the insulating film 1123 can fully adhere to the surface of each component; then, adhesive is applied to the bottom surface 11226, and the adhesive 11241 (or tape) completely covers the entire area of ​​the second bottom film 11236, and can also extend to the first bottom film 11235, covering 30% to 100% of the area of ​​the first bottom film 11235 (ensuring that the overlapping area of ​​the first bottom film 11235 and the second bottom film 11236 is completely covered).

[0249] The second side 11225 can also be covered with adhesive. The adhesive 11241 (or tape) extends upward along the second side 11225. The adhesive 11241 (or tape) can cover 1 / 10 to 1 / 2 of the height of the second side film 11234 and 10% to 60% of the area of ​​the second side film 11234, ensuring that the joint between the second side film 11234, the first side film 11233 and the first bottom film 11235 and the second bottom film 11236 is completely wrapped by the adhesive 11241.

[0250] After the adhesive is applied, compaction can be performed. After the adhesive is applied, the adhesive 11241 is compacted using rollers or pressure blocks, with the pressure controlled at 0.3~0.5MPa, to ensure that the adhesive 11241 is tightly adhered to the surface of the insulating film 1123 without bubbles or wrinkles, thereby improving the bonding stability.

[0251] The colloid 11241 should at least cover the entire surface of the second base film 11236 (including the overlapping area between the second base films 11236), the overlapping area of ​​the first base film 11235 and the second base film 11236, and the joint area of ​​the second side film 11234 and the second base film 11236, to ensure that these critical joints are sealed by the colloid 11241 and reduce the risk of gap residue.

[0252] In this example, the first bottom film 11235, the second bottom film 11236, and the second side film 11234 are firmly connected as a whole to form a closed bottom protective structure. Compared with the hot melt process, the adhesive application operation does not require high-temperature heating, which reduces the damage to the insulating film 1123 and the diaphragm of the electrode assembly 11221 caused by the hot melt process. At the same time, it eliminates the need for hot melt equipment debugging and hot melt point quality inspection, thus simplifying the process.

[0253] In this embodiment, the covering design of the colloid 11241 ensures that there is no relative displacement space between the bottom film and the side film. Combined with the overlapping structure of the second bottom film 11236 and the first bottom film 11235, the overall covering stability of the insulating film 1123 is further improved, ensuring that there will be no problems such as bottom film detachment or side film displacement during long-term use. It also increases the height of the bottom surface 11226 of the electrode assembly 1122, making it less likely for the bottom corner 11228 of the electrode assembly 1122 to touch the arc chamfer 11227 at the bottom of the outer shell 1121.

[0254] In some embodiments, the preparation method does not require a heat-melting process for the insulating film 1123.

[0255] In related technologies, a hot-melt process is used during the assembly of the insulating film 1123. High temperatures are used to bond and fix the insulating film 1123 to components such as the lower plastic 11215 and the top cover, preventing displacement after wrapping. However, this process has significant drawbacks: First, the hot-melt process requires precise control of temperature and pressure, making equipment debugging complex and increasing production energy consumption; second, high temperatures can easily damage the separator of the electrode assembly 11221, increasing the risk of battery short circuits; third, the hot-melt point may shift or detach, causing the insulating film 1123 to loosen and affecting its insulation protection effect; fourth, the hot-melt process requires an additional workstation, extending the production cycle time, which contradicts the goal of streamlining the process.

[0256] Therefore, in this example, the dual design of "structural positioning combined with adhesive fastening" completely replaces the fixing function of the hot-melt process. Specifically, in the structural positioning, the first positioning structure 11239 of the top film 11231 is inserted and engaged with the second positioning structure 11216 of the cover assembly 11211, and the third positioning structure 11240 of the first side film 11233 is inserted and engaged with the fourth positioning structure 11217 of the cover assembly 11211, forming a multi-dimensional rigid positioning that restricts the displacement freedom of the insulating film 1123. After covering the second bottom film 11236, the bottom surface 11226 and the area of ​​the second side surface 11225 near the bottom surface 11226 are covered with insulating tape (adhesive 11241). The adhesive 11241 firmly bonds the first bottom film 11235, the second bottom film 11236 and the second side film 11234 to form a closed and fixed structure, ensuring that the relative position of the insulating film 1123 as a whole with the electrode assembly 1122 and the cover assembly 11211 is fixed, and a long-term stable coating effect can be achieved without heat melting.

[0257] With separate feeding, the insulating film 1123 and the cover assembly 11211 are fed and stacked independently. If a hot melt process is used, the two need to be integrated in advance, which violates the core design of "separate feeding". The non-hot melt design ensures that after separate feeding, it can still be fixed by positioning and adhesive, which meets the goal of improving the automation cycle time.

[0258] In addition, the second bottom film 11236 overlaps with the first bottom film 11235 after being bent, physically closing the bottom gap. Combined with adhesive sealing of the tiny gap, the path of electrode powder accumulation can be blocked without heat fusion, thus solving the risk of leakage. Furthermore, the insulating film 1123 completely covers the tab 11222, achieving insulation isolation between the tab 11222 and the cover assembly 11211 without heat fusion, eliminating the adhesive application process on the back of the tab 11222, and further simplifying the process.

[0259] In this embodiment, no hot-melting process is required, which can protect the core components (such as separators) of the electrode assembly 11221, reduce the quality risks such as short circuits and insulation failures of the battery cell 1120, and improve the battery yield and reliability.

[0260] In some embodiments, refer to Figure 5 and Figure 8 As shown, the top membrane 11231 has a first clearance hole 11237 and a second clearance hole 11238, and an explosion-proof valve 1125 is connected to the cover assembly 11211; in the step where the electrode tab 11222 and the adapter are positioned and connected to the top membrane 11231 of the insulating membrane 1123, the method further includes setting the explosion-proof valve 1125 opposite to the first clearance hole 11237, and setting the area of ​​the adapter connected to the electrode terminal 1124 opposite to the second clearance hole 11238.

[0261] Specifically, the first clearance hole 11237 can reserve opening space for the explosion-proof valve 1125, so that the top membrane 11231 will not adhere to and cover the explosion-proof valve 1125. This ensures that when the internal pressure of the battery cell 1120 is abnormal, the explosion-proof valve 1125 can smoothly break through the sealing structure of the cover assembly 11211 to release pressure, thus ensuring the reliability of the battery cell 1120. At the same time, it reduces the risk of friction or confinement caused by direct contact between the top membrane 11231 and the explosion-proof valve 1125, as well as the risk of failure of the explosion-proof valve 1125.

[0262] The second clearance hole 11238 can expose the welding area between the adapter and the electrode terminal 1124, providing an unobstructed working channel for laser welding, ensuring that the welding energy is accurately applied to the welding surface, reducing the risk of insufficient welding strength or incomplete welding caused by the obstruction of the top film 11231; at the same time, it reduces the probability of high temperature damage to the top film 11231 during welding, and ensures the insulation performance of the insulating film 1123.

[0263] In the step where both the tab 11222 and the adapter are positioned and connected to the top film 11231 of the insulating film 1123, the positioning and engagement of the clearance hole is performed synchronously with other positioning structures. Specifically, after the cover assembly 11211 is loaded, the position coordinates of the explosion-proof valve 1125 on the cover assembly 11211 can be captured by a vision positioning system to establish a reference positioning point. When the insulating film 1123 is loaded, the automated equipment adjusts the posture of the insulating film 1123 according to the reference positioning point, so that the first clearance hole 11237 of the top film 11231 is precisely aligned with the explosion-proof valve 1125. When the electrode assembly 1122 is loaded, the position of the electrode assembly 1122 is adjusted with the second clearance hole 11238 of the top film 11231 as the positioning reference, so that the welding area of ​​the adapter is completely embedded in the second clearance hole 11238, while the tab 11222 and the top film 11231 are tightly fitted together.

[0264] In this embodiment, during the process of assembling the top membrane 11231 with the tabs 11222 and the adapter on the electrode assembly 1122, the first clearance hole 11237 is matched with the explosion-proof valve 1125, and the second clearance hole 11238 is matched with the welding position on the adapter. This reduces the risk of functional failure caused by misalignment of the clearance holes and ensures the reliability of the circuit connection of the battery cell 1120.

[0265] In some embodiments, refer to Figure 5 and Figure 8 As shown, the top film 11231 has a first positioning structure 11239, and the cover assembly 11211 has a second positioning structure 11216; in the step where the tab 11222 and the adapter are positioned and connected to the top film 11231 of the insulating film 1123, the method further includes inserting and engaging the first positioning structure 11239 and the second positioning structure 11216.

[0266] Specifically, during the feeding of the insulating film 1123, the automated equipment adjusts the posture of the insulating film 1123 according to the reference positioning point, so that the first clearance hole 11237 of the top film 11231 is precisely aligned with the explosion-proof valve 1125, and at the same time, the first positioning structure 11239 of the top film 11231 and the second positioning structure 11216 of the cover assembly 11211 are inserted and engaged, completing the dual positioning of the insulating film 1123 and the cover assembly 11211; during the feeding of the electrode assembly 1122... Using the second clearance hole 11238 of the top membrane 11231 as the positioning reference, the position of the electrode assembly 1122 is adjusted so that the welding area of ​​the adapter is completely embedded in the second clearance hole 11238. At the same time, the electrode tab 11222 is tightly attached to the top membrane 11231, and the third positioning structure 11240 of the first side membrane 11233 and the fourth positioning structure 11217 of the cover assembly 11211 are inserted and engaged, thus achieving the synchronous completion of the clearance hole alignment and connection structure positioning.

[0267] During long-term use, the battery cell 1120 will face conditions such as vibration, temperature changes, and expansion of the electrode assembly 1122. The insulating film 1123, which is traditionally positioned, is prone to loosening and displacement. In this embodiment, the multiple interlocking joints form a rigid positioning structure, which can resist the influence of external forces such as vibration and expansion, ensuring the long-term stability of the connection between the insulating film 1123 and the cover assembly 11211 and the electrode assembly 1122. At the same time, the positioning structure works in conjunction with the subsequent adhesive fastening process to form a closed and fixed system for the insulating film 1123, reducing the risk of coating failure caused by loosening of the insulating film 1123, protecting the structural integrity of the electrode assembly 1122, and extending the service life of the battery cell 1120.

[0268] In this embodiment, the positioning structure improves the long-term stability and failure resistance of the insulating film 1123, reduces battery failures caused by loosening of the insulating film 1123, and enhances the environmental adaptability of the battery.

[0269] The above are merely preferred embodiments of this application, and only specifically describe the technical principles of this application. These descriptions are only for explaining the principles of this application and should not be construed as limiting the scope of protection of this application in any way. Based on this explanation, any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application, as well as other specific embodiments of this application that can be conceived by those skilled in the art without creative effort, should be included within the scope of protection of this application.

Claims

1. A battery cell, comprising a housing and an electrode assembly disposed within a cavity of the housing, the electrode assembly comprising at least one electrode component, the electrode assembly having a top surface, a bottom surface, two opposing first side surfaces, and two opposing second side surfaces, characterized in that, The outer casing includes a casing body and a cover assembly, the cover assembly being connected to the casing body and together with the casing body forming the accommodating cavity; the battery cell further includes an insulating film, the insulating film comprising: A top film is attached to the top surface, and the top film is disposed opposite to the cover assembly; The top film has two side-combination films, which are respectively disposed on opposite sides of the top film. Each side-combination film includes a first side film, a first bottom film, and two second side films. The two first side films are respectively bonded to the two first side films in a one-to-one correspondence. In a first direction, the two second side films are respectively connected to the two sides of the first side film. Two second side films located on the same side are laminated and bonded to one second side film, and the other two second side films located on the same side are laminated and bonded to the other second side film. In a second direction, the top film and the first bottom film are respectively connected to the two sides of the first side film. The membrane layers are laminated and bonded to the bottom surface, with the first direction perpendicular to the second direction; at least one of the side assembly membranes further includes two second bottom membranes, which are disposed at both ends of the first bottom membrane in the first direction, and are connected to the end of the second side membrane near the first bottom membrane, and are laminated and bonded to the bottom surface or the first bottom membrane; the end of the first side membrane facing the cover assembly has a third positioning structure protruding from the edge of the first side membrane; the side of the cover assembly facing the top membrane has a fourth positioning structure, and the third positioning structure and the fourth positioning structure are interlocked along the second direction.

2. The battery cell as described in claim 1, characterized in that, The second side film in one of the side combination films has a first width, and the second side film in the other side combination film has a second width, the second width being less than the first width, and the sum of the first width and the second width being greater than the width of the second side film; The first bottom film in one of the side-mounted films has a third width, and the first bottom film in the other side-mounted film has a fourth width, the fourth width being less than the third width, and the sum of the third width and the fourth width being greater than the width of the bottom surface.

3. The battery cell as described in claim 2, characterized in that, The second width is 0.25 to 0.75 times the first width; and / or, the fourth width is 0.25 to 1.0 times the third width.

4. The battery cell as described in claim 1, characterized in that, The second base film has a preset width, which is less than or equal to the width of the second side film that is matched and connected to the current second base film.

5. The battery cell as described in claim 1, characterized in that, The second base film has a preset length, which is equal to the size of the first base film that matches the current second base film.

6. The battery cell as described in claim 1, characterized in that, The electrode assembly has tabs; the electrode assembly also includes an adapter, and the battery cell also includes an electrode terminal and an explosion-proof valve. The electrode assembly and the adapter are both disposed within the accommodating cavity. The tabs on the electrode assembly are electrically connected to the electrode terminals via the adapter, and the electrode terminals and the explosion-proof valve are both connected to the outer casing. The top membrane covers the tabs. The top membrane has a first clearance hole and a second clearance hole. The explosion-proof valve is disposed opposite to the first clearance hole, and the connection position of the adapter and the electrode terminal is disposed opposite to the second clearance hole.

7. The battery cell as described in claim 1, characterized in that, The top membrane has a first positioning structure, and the cover assembly has a second positioning structure. Along the second direction, the first positioning structure and the second positioning structure are interlocked.

8. The battery cell as described in claim 7, characterized in that, The cover assembly includes a cover and a lower plastic. The cover and the shell body together form a receiving cavity. The lower plastic is connected to the cover and disposed on the side of the cover facing the receiving cavity. The second positioning structure is disposed on the lower plastic.

9. The battery cell as described in claim 1, characterized in that, The cover assembly includes a cover and a lower plastic part. The cover and the shell body together form a receiving cavity. The lower plastic part is connected to the cover and disposed on the side of the cover facing the receiving cavity. The fourth positioning structure is disposed on the cover.

10. The battery cell as described in claim 1, characterized in that, The cover assembly includes a cover and a lower plastic. The cover and the shell body together form a receiving cavity. The lower plastic is connected to the cover and disposed on the side of the cover facing the receiving cavity. Along the first direction, one or both ends of the lower plastic have positioning protrusions. Corresponding to the positioning protrusions, one or both ends of the top membrane have avoidance areas. The positioning protrusions are limited between the two first side membranes by the avoidance areas.

11. A battery device, characterized in that, The battery device includes a battery cell as described in any one of claims 1-10.

12. An electrical appliance, characterized in that, The electrical device includes a single battery cell as described in any one of claims 1-10; or, The electrical device includes the battery device as described in claim 11, the battery device being used to store or provide electrical energy.

13. A method for preparing a single battery cell, characterized in that, The preparation method includes the following steps: A sheet of material for prefabricating the insulating film in a battery cell as described in any one of claims 1-10; Prefabricated electrode assembly; At a preset workstation, the cover assembly, the insulating film, and the electrode assembly are placed separately using a separate loading method. The insulating film is in a sheet-like unfolded state, with the top film of the insulating film aligning with the inner side of the cover assembly. The electrode assembly is then assembled and positioned with the insulating film, with the third positioning structure and the fourth positioning structure interlocked. The two first side films of the insulating film are respectively attached to the two first side films of the electrode assembly. The first base film is covered, and the two first base films are folded in sequence so that the two first base films are attached to and stacked with the bottom surface of the electrode assembly; The second side film is covered, and the four second side films are folded toward the corresponding second side of the electrode assembly, so that two second side films are attached and stacked on each second side; correspondingly, the four second bottom films are stacked in pairs. The second bottom film is covered, and the two second bottom films, which are respectively stacked in pairs, are folded towards the bottom surface of the electrode assembly, so that the two stacked second bottom films are respectively attached to and stacked with the first bottom film. Electrically connect the electrode terminals and weld the electrode terminals to the electrode assembly; The coated electrode assembly is then inserted into the receiving cavity of the outer shell body, thereby encapsulating the cover assembly with the shell body.

14. The method for preparing a single battery cell as described in claim 13, characterized in that, The electrode assembly includes an adapter and at least two electrode components; The step of the prefabricated electrode assembly includes: connecting the tabs of the at least two electrode assemblies to the adapter to form the electrode assembly; The step of assembling and positioning the electrode assembly with the insulating film, wherein the two first side films in the insulating film are respectively attached to the two first sides of the electrode assembly, includes: at a preset station, positioning and connecting the electrode tab and the adapter to the top film of the insulating film, wherein the two first side films in the insulating film are respectively matched and attached to the two first sides of the outer electrode assembly in the electrode assembly; and then, folding the electrode assembly to stack it so that the first sides of adjacent electrode assemblies are opposite or attached to each other, maintaining the two first side films respectively attached to the two first sides of the outer electrode assembly.

15. The method for preparing a battery cell as described in claim 13 or 14, characterized in that, After the step of covering the second base film, adhesive is applied to the bottom surface of the electrode assembly and the portion of the second side surface near the bottom surface, so that the adhesive covers at least the second base film, at least a portion of the first base film, and at least a portion of the second side film.

16. The method for preparing a battery cell as described in claim 13 or 14, characterized in that, In the preparation method described above, there is no need to perform a hot-melt process on the insulating film.

17. The method for preparing a single battery cell as described in claim 14, characterized in that, The top membrane has a first clearance hole and a second clearance hole, and the cover assembly is connected to an explosion-proof valve; in the step where the electrode tab and the adapter are both positioned and connected to the top membrane of the insulating membrane, the method further includes setting the explosion-proof valve opposite to the first clearance hole, and setting the area of ​​the adapter connected to the electrode terminal opposite to the second clearance hole.

18. The method for preparing a single battery cell as described in claim 14, characterized in that, The top film has a first positioning structure, and the cover assembly has a second positioning structure; in the step where the tabs and the adapter are both positioned and connected to the top film of the insulating film, the method further includes inserting and engaging the first positioning structure and the second positioning structure.

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