Battery cell, battery device, energy storage device, energy storage system and charging network

Abstract

A battery cell, a battery device, an energy storage device, an energy storage system and a charging network. The battery cell comprises: a housing; electrode terminals, provided on a first wall of the housing; an electrode assembly set, accommodated in an accommodating cavity of the housing, the electrode assembly set comprising a main body portion and tabs, the main body portion comprising a first end surface facing the first wall and an outer peripheral surface intersecting with the first end surface and surrounding the first end surface, and the tabs being located on the first end surface; a current collecting member, used for electrically connecting the electrode terminals and the tabs; a first insulating film, covering the outer peripheral surface; and a second insulating film, comprising a body portion and an extension portion which are bent relative to each other, wherein the body portion is arranged between the current collecting member and the first wall so as to isolate the current collecting member from the first wall, the extension portion covers a partial area of the outer peripheral surface, and the first insulating film wraps around and fixes the extension portion. With respect to the battery cell, the battery device, the energy storage device, the energy storage system and the charging network in the embodiments of the present application, the insulation performance and reliability of the battery cell can be improved.

Description

Battery cells, battery packs, energy storage devices, energy storage systems, and charging networks Cross-reference to related applications

[0001] This application claims priority to Chinese patent application CN202520279182.4, filed on February 20, 2025, entitled “Battery cell, battery device, energy storage device, energy storage system and charging network”, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of batteries, and more specifically, to a battery cell, a battery device, an energy storage device, an energy storage system, and a charging network. Background Technology

[0003] Energy conservation and emission reduction are key to the sustainable development of the automotive industry, and electric vehicles, due to their energy-saving and environmentally friendly advantages, have become an important component of this sustainable development. For electric vehicles, battery technology is a crucial factor in their development.

[0004] In the fabrication of a single battery cell, after the electrode assembly is prepared, it needs to be installed into a metal casing to complete the assembly. Improving the insulation performance between the electrode assembly and the casing is a technical problem that urgently needs to be solved. Summary of the Invention

[0005] This application provides a battery cell, a battery device, an energy storage device, an energy storage system, and a charging network, which can improve the insulation performance and reliability of the battery cell.

[0006] In a first aspect, a battery cell is provided, comprising: a housing having a receiving cavity; an electrode terminal disposed on a first wall of the housing; an electrode assembly assembly housed in the receiving cavity, the electrode assembly assembly including at least one electrode assembly, the electrode assembly assembly including a body portion and a tab, the body portion including a first end face and an outer peripheral face, the outer peripheral face intersecting and surrounding the first end face, the tab being located on the first end face, the first end face facing the first wall; a current collector for electrically connecting the electrode terminal and the tab; a first insulating film covering the outer peripheral face; and a second insulating film including a relatively bent body portion and an extension portion, the body portion being disposed between the current collector and the first wall to isolate the current collector and the first wall, the extension portion covering a portion of the outer peripheral face, and the first insulating film wrapping and fixing the extension portion.

[0007] Therefore, in the battery cell of this application embodiment, the first insulating film can effectively isolate the outer peripheral surface of the electrode assembly from the outer casing; the second insulating film can further isolate the first end face where the tab is located from the first wall, and the body of the second insulating film is located between the current collector and the first wall, which can reduce the influence of the second insulating film on the electrical connection between the current collector and the tab, that is, it can improve the insulation performance between the electrode assembly and the outer casing, and reduce the influence between the electrode assembly and the current collector, thereby improving the reliability of the battery cell.

[0008] In some embodiments, the second insulating film includes two opposing extensions, each extension covering at least a portion of one of the two large surfaces of the outer peripheral surface, where the large surface is the surface with the largest area. By configuring the second insulating film with two opposing extensions, the second insulating film achieves a relatively symmetrical structure, which improves its stability. Furthermore, each extension covers a large surface of the outer peripheral surface, facilitating the first insulating film to cover and fix the second insulating film, further enhancing structural stability and reducing the risk of battery cell insulation failure.

[0009] In some embodiments, the battery cell further includes: an insulating member fixed to the first wall and located between the first wall and the first end face, and a first insulating film fixed to the insulating member. The insulating member can be used to isolate the first end face from the first wall; in addition, the first insulating film covering the outer peripheral surface is fixed to the insulating member to further improve the stability of the various components inside the battery cell.

[0010] In some embodiments, the body portion is disposed between the current collector and the insulating member, such that the second insulating film and the insulating member are used together to isolate the electrode assembly assembly from the first wall, and to isolate the current collector from the first wall, thereby improving the insulation effect inside the battery cell.

[0011] In some embodiments, the insulating member includes a first electrode lead-out hole, through which the electrode terminal is connected to the current collector to achieve electrical connection between the electrode terminal and the tab, thereby outputting electrical energy.

[0012] In some embodiments, the current collector includes an electrode terminal connection portion, and the body portion includes a second electrode lead-out hole. The electrode terminal and / or the electrode terminal connection portion pass through the second electrode lead-out hole so that the electrode terminal is connected to the electrode terminal connection portion, thereby realizing the electrical connection between the electrode terminal and the tab, and thus outputting electrical energy.

[0013] In some embodiments, the current collector includes a tab connection portion for electrical connection with the tab, the tab connection portion being located between the body portion and the tab to reduce the influence of the second insulating film on the electrical connection between the tab connection portion and the tab.

[0014] In some embodiments, the battery cell further includes a third insulating film, which includes a first region and a second region that are bent relative to each other. The first region is bonded to the tab connection portion, and the second region is bonded to and covers a portion of the outer peripheral surface. The second insulating film covers the third insulating film, and along the thickness direction of the first wall, the length of the extension covering the outer peripheral surface is greater than the length of the second region covering the outer peripheral surface. The third insulating film isolates the tab connection portion from the first wall, thereby improving the insulation reliability between the tab connection portion and the first wall. The second insulating film further secures the third insulating film, thereby improving the stability and reliability of the third insulating film.

[0015] In some embodiments, the melting point of the third insulating film is greater than that of the second insulating film. Thus, during the use of the battery cell assembly, when the temperature rises, the third insulating film is less prone to damage than the second insulating film, improving the insulation reliability between the tab and the first wall and reducing the risk of insulation failure.

[0016] In some embodiments, the battery cell further includes a pressure relief mechanism disposed on the first wall, and the body portion further includes a pressure relief hole corresponding to the pressure relief mechanism. Thus, when thermal runaway occurs in the battery cell, the pressure relief hole reduces the obstruction of the second insulating film from the discharge of pollutants from the battery cell, allowing the pressure relief mechanism to be activated promptly to quickly discharge pollutants and improve the reliability of the battery cell.

[0017] In some embodiments, the battery cell further includes a liquid injection structure disposed on the first wall, and the body portion further includes a liquid injection hole corresponding to the liquid injection structure. The liquid injection hole allows the electrolyte to smoothly wet the electrode assembly, facilitating improved processing efficiency of the battery cell.

[0018] In some embodiments, along the thickness direction of the first wall, the range of the ratio of the length of the extension covering the outer peripheral surface to the length of the outer peripheral surface is [0.08, 0.25]. Setting this ratio to be greater than or equal to 0.08 can increase the area of ​​the outer peripheral surface covered by the extension, and also increase the area of ​​the extension covered by the first insulating film, improving the stability between the extension and the first insulating film, thereby improving the structural stability of the battery cell. Setting this ratio to be less than or equal to 0.25 can limit the area of ​​the extension. Considering that the first insulating film can cover the outer peripheral surface, appropriately limiting the area of ​​the extension can reduce the area of ​​overlap between the extension and the first insulating film, reduce the space occupied by the extension and the first insulating film on the outer peripheral surface, improve the space utilization of the battery cell, reduce the weight of the battery cell, and thus improve the energy density of the battery cell.

[0019] In some embodiments, the electrode assembly is a stacked structure. The first insulating film can also be used to fix the electrode assembly assembly to improve its stability. Especially when the electrode assembly assembly includes multiple electrode assemblies, the first insulating film surrounds the outer peripheral surface of the electrode assembly assembly. This first insulating film can increase structural stability, reduce misalignment and movement between the multiple stacked electrode sheets, and thus improve the performance of the electrode assembly assembly.

[0020] In some embodiments, the electrode assembly includes a first surface and a second surface disposed opposite to each other along the thickness direction of the electrode assembly. The electrode assembly also includes a plurality of fixing structures spaced apart, each of which extends from the edge of the first surface along the thickness direction of the electrode assembly to the edge of the second surface. The second insulating film covers the plurality of fixing structures. For stacked electrode assemblies, by providing multiple fixing structures, multiple electrodes of the electrode assembly can be fixed, thereby improving the stability of the electrode assembly. Furthermore, in this embodiment, the first insulating film and the second insulating film are at least disposed on the outer peripheral surface of the main body of the electrode assembly assembly, i.e., outside the plurality of fixing structures disposed on the outer peripheral surface, which can reduce movement and misalignment between the multiple electrode assemblies, thereby further improving the stability of the electrode assembly assembly.

[0021] In some embodiments, the first insulating film includes at least one insulating sheet, which is folded and adhered to the outer peripheral surface. Compared to methods that use materials such as heat-shrink film to cover the outside of the electrode assembly, the first insulating film in this embodiment adopts a sheet structure. At least one insulating sheet can be wrapped and adhered to the outer peripheral surface by folding, which simplifies the processing method, improves processing efficiency, and allows for a tighter fit between the first insulating film and the main body of the electrode assembly, thereby improving the space utilization of the battery cell.

[0022] In some embodiments, the first insulating film includes two insulating sheets, which respectively cover two large surfaces of the outer peripheral surface and overlap and adhere to two side surfaces of the outer peripheral surface to cover the outer peripheral surface. The area of ​​the side surfaces of the outer peripheral surface is smaller than the area of ​​the large surfaces of the outer peripheral surface. By providing relatively complete insulating sheets on the two large surfaces of the outer peripheral surface and overlapping areas of the two insulating sheets on the two side surfaces of the outer peripheral surface, the processing technology is simple, improving processing efficiency and structural stability.

[0023] In some embodiments, the electrode assembly includes a first electrode assembly and a second electrode assembly, and an insulating sheet that is attached to the side of the outer peripheral surface of the first electrode assembly is attached to the side of the outer peripheral surface of the second electrode assembly to improve structural stability and reduce the risk of insulation failure of the first insulating film.

[0024] In some embodiments, the main body portion further includes a second end face opposite to the first end face, the outer peripheral surface connects the first end face and the second end face, and the first insulating film covers at least a portion of the second end face to isolate the second end face from the housing.

[0025] In some embodiments, the first insulating film is adhered to and covers the edge region of the second end face; the battery cell further includes a separator, which is adhered to and covers the area of ​​the second end face not covered by the first insulating film, and the separator covers the first insulating film. By directly adhering and fixing the first insulating film to the outer peripheral surface of the main body and the edge region of the second end face, the electrode assembly assembly and the housing can be effectively isolated, and the fixing method does not require heat fusion, reducing processing steps, facilitating the processing of the battery cell, and improving the processing efficiency of the battery cell. In addition, the first insulating film covers part of the second end face of the main body, rather than the entire area, which can reduce weight; at the same time, the separator is adhered to and covers the area of ​​the second end face not covered by the first insulating film, and covers the first insulating film adhered to the edge of the second end face. The separator can be used to isolate the second end face of the electrode assembly assembly and the housing, and the separator is fixed by adhesion, which facilitates processing and can also improve the processing efficiency of the battery cell.

[0026] In some embodiments, the housing includes: a housing having an opening; and a cover plate for closing the opening to form the receiving cavity, the cover plate including the first wall to facilitate processing and assembly.

[0027] In a second aspect, a battery device is provided, comprising: a plurality of battery cells as described in the first aspect or any one of the embodiments of the first aspect.

[0028] Thirdly, an energy storage device is provided, comprising: a plurality of battery cells as described in the first aspect or any one embodiment of the first aspect, or a plurality of battery devices as described in the second aspect, wherein the battery cell or the battery device is used to store or provide electrical energy.

[0029] Fourthly, an energy storage system is provided, comprising: a power conversion device; and the energy storage device described in the third aspect, wherein the power conversion device is used to electrically connect a power generation device and the energy storage device.

[0030] Fifthly, a charging network is provided, comprising: a charging pile; an energy storage device as described in the third aspect or an energy storage system as described in the fourth aspect, the energy storage device being used to provide electrical energy to the charging pile. Attached Figure Description

[0031] Figure 1 is a schematic diagram of the structure of a battery cell according to an embodiment of this application;

[0032] Figure 2 is an exploded view of a partial structure of a battery cell according to an embodiment of this application;

[0033] Figure 3 is a schematic diagram of the structure of an electrode assembly according to an embodiment of this application;

[0034] Figure 4 is a schematic diagram of the internal structure of a battery cell according to an embodiment of this application;

[0035] Figure 5 is a cross-sectional schematic diagram of a battery cell according to an embodiment of this application;

[0036] Figure 6 is another partial cross-sectional view of a battery cell according to an embodiment of this application;

[0037] Figure 7 is a schematic diagram of the structure of the second insulating film according to an embodiment of this application;

[0038] Figure 8 is a schematic diagram of the current collector, second insulating film and insulating element in a battery cell according to an embodiment of this application;

[0039] Figure 9 is a partial cross-sectional schematic diagram of a battery cell according to another embodiment of this application;

[0040] Figure 10 is a cross-sectional schematic diagram of an electrode assembly according to an embodiment of this application;

[0041] Figure 11 is a cross-sectional schematic diagram of an electrode assembly according to another embodiment of this application;

[0042] Figure 12 is a front view schematic diagram of an electrode assembly according to an embodiment of this application;

[0043] Figure 13 is a bottom view of an electrode assembly according to an embodiment of this application;

[0044] Figure 14 is a top view of an electrode assembly wrapped with a first insulating film according to an embodiment of this application;

[0045] Figure 15 is a top view of an electrode assembly wrapped with a first insulating film according to another embodiment of this application;

[0046] Figure 16 is a top view of an electrode assembly wrapped with a first insulating film according to another embodiment of this application.

[0047] Figure 17 is a top view of an electrode assembly wrapped with a first insulating film according to another embodiment of this application.

[0048] Figure 18 is a cross-sectional schematic diagram of a battery cell according to another embodiment of this application;

[0049] Figure 19 is a partial cross-sectional schematic diagram of a battery cell according to another embodiment of this application;

[0050] Figure 20 is a schematic diagram of the second end face of the main body portion to which the first insulating film is pasted, according to another embodiment of this application;

[0051] Figure 21 is a schematic diagram of the internal structure of a battery cell according to another embodiment of this application;

[0052] Figure 22 is a top view of a separator according to another embodiment of this application;

[0053] Figure 23 is a bottom view of an electrode assembly with a separator and a first insulating film attached, according to another embodiment of this application.

[0054] The accompanying drawings are not drawn to scale. Detailed Implementation

[0055] The technical solutions in the embodiments of this application will now be described with reference to the accompanying drawings.

[0056] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0057] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in the description of this application 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 description, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the description, claims, or accompanying drawings of this application are used to distinguish different objects, not to describe a specific order or hierarchy.

[0058] In this application, the reference to "embodiment" means that a specific 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 mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described in this application can be combined with other embodiments.

[0059] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "attachment" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0060] 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, or B existing alone. Additionally, in this application, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0061] In the embodiments of this application, the same reference numerals denote the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width, and other dimensions of various components in the embodiments of this application shown in the accompanying drawings, as well as the overall thickness, length, width, and other dimensions of the integrated device, are merely illustrative and should not constitute any limitation on this application.

[0062] In this application, "multiple" refers to two or more (including two), and similarly, "multiple groups" refers to two or more (including two), and "multiple pieces" refers to two or more (including two).

[0063] In this embodiment of the application, the battery cell can be a secondary battery, which refers to a battery cell that can be recharged to activate the active materials and continue to be used after the battery cell has been discharged.

[0064] The battery cell 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.

[0065] A single battery cell typically includes an electrode assembly. The electrode assembly includes a positive electrode, a negative electrode, and a separator, with the separator positioned between the positive and negative electrodes. During the charging and discharging process of a single battery cell, active ions (such as lithium ions) repeatedly insert and extract between the positive and negative electrodes. The separator, positioned between the positive and negative electrodes, prevents short circuits while allowing active ions to pass through.

[0066] In some embodiments, the positive electrode can be a positive electrode sheet, which may include a positive current collector and a positive active material disposed on at least one surface of the positive current collector.

[0067] 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.

[0068] 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.).

[0069] 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.

[0070] In some embodiments, the negative electrode can be a negative electrode sheet, and the negative electrode sheet can include a negative current collector.

[0071] 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.).

[0072] As an example, the negative electrode sheet may include a negative current collector and a negative active material disposed on at least one surface of the negative current collector.

[0073] 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.

[0074] 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.

[0075] In some embodiments, the negative electrode can be made of 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 contain a negative electrode active material.

[0076] As an example, negative electrode active materials can be filled or / and deposited within the negative electrode current collector.

[0077] In some embodiments, the positive current collector can be made of aluminum, and the negative current collector can be made of copper.

[0078] In some embodiments, the electrode assembly further includes an isolator disposed between the positive and negative electrodes.

[0079] In some embodiments, the separator is a separator membrane. This application does not impose any particular limitation on the type of separator membrane; any porous separator membrane with good chemical and mechanical stability can be selected.

[0080] 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.

[0081] In some embodiments, the battery cell also includes an electrolyte, which acts as a conductor of ions between the positive and negative electrodes. This application does not impose specific limitations on the type of electrolyte; it can be selected according to requirements. The electrolyte can be liquid, gel, or solid.

[0082] The electrode assembly can be a wound structure, a stacked structure, or a hybrid structure of wound and stacked.

[0083] In some embodiments, the electrode assembly is a wound structure. The positive electrode and the negative electrode are wound into a wound structure.

[0084] In some implementations, the electrode assembly is a stacked structure.

[0085] As an example, multiple positive and negative electrode plates can be set, and multiple positive and multiple negative electrode plates can be stacked alternately.

[0086] As an example, multiple positive electrode sheets can be set, and negative electrode sheets are folded to form multiple stacked folded segments, with a positive electrode sheet sandwiched between adjacent folded segments.

[0087] As an example, both the positive and negative electrode sheets are folded to form multiple stacked folded segments.

[0088] As an example, multiple separators can be provided, each positioned between any adjacent positive or negative electrode plates.

[0089] As an example, the separator can be continuously arranged between any adjacent positive or negative electrode plates by folding or rolling.

[0090] In some embodiments, the electrode assembly can be cylindrical, flat, or polygonal, etc.

[0091] In some embodiments, the electrode assembly has tabs that allow current to be drawn from the electrode assembly. The tabs include a positive tab and a negative tab.

[0092] During the fabrication of a battery cell, after the electrode assembly is prepared, it needs to be installed into a metal casing to complete the assembly. To achieve insulation between the electrode assembly and the casing, an insulating film can be included on the outer surface of the electrode assembly. However, since the tabs of the electrode assembly need to be electrically connected to the current collector to output electrical energy, the outer surface of the electrode assembly without tabs is usually wrapped with an insulating film, while the end face where the tabs are located is not wrapped with an insulating film. However, there is still a risk of insulation failure between the end face without an insulating film and the casing, as well as between the tabs and the casing, which may affect the performance and lifespan of the battery cell.

[0093] Therefore, the battery cell, battery device, energy storage device, energy storage system, and charging network of the present application embodiments can solve the above-mentioned technical problems. The battery cell of the present application embodiments includes a casing, electrode terminals, an electrode assembly assembly, a current collector, a first insulating film, and a second insulating film. The electrode terminals are disposed on the first wall of the casing; the electrode assembly assembly is housed within a receiving cavity of the casing, and the electrode assembly assembly includes at least one electrode assembly. The electrode assembly assembly includes a main body and a tab. The main body includes a first end face and an outer peripheral face. The tab is disposed on the first end face, and the outer peripheral face intersects with and surrounds the first end face, with the first end face facing the first wall. The current collector is used to electrically connect the tab and the electrode terminal. The first insulating film covers the outer peripheral face. The second insulating film includes a relatively bent body portion and an extension portion. The body portion is disposed between the current collector and the first wall to isolate the current collector and the first wall. The extension portion covers a portion of the outer peripheral face, and the first insulating film wraps around and fixes the extension portion. The first insulating film effectively isolates the outer peripheral surface of the electrode assembly from the outer casing. The second insulating film further isolates the first end face where the tab is located from the first wall. Since the body of the second insulating film is located between the current collector and the first wall, it reduces the impact of the second insulating film on the electrical connection between the current collector and the tab. This improves the insulation performance between the electrode assembly and the outer casing, reduces the impact on the connection between the electrode assembly and the current collector, and enhances the reliability of the individual battery cells. Furthermore, the fixation of the first insulating film to the body of the electrode assembly simultaneously fixes the second insulating film, facilitating processing and improving structural stability.

[0094] Figure 1 shows a structural schematic diagram of the battery cell 20 according to an embodiment of this application; Figure 2 shows an exploded schematic diagram of a partial structure of the battery cell 20 according to an embodiment of this application; Figure 3 shows a structural schematic diagram of the electrode assembly 22 of the battery cell 20 according to an embodiment of this application. As shown in Figures 1 to 3, the battery cell 20 according to an embodiment of this application includes: a housing 21, electrode terminals 214, and an electrode assembly 22.

[0095] Specifically, the housing 21 has a receiving cavity; the electrode terminal 214 is disposed on the first wall 201 of the housing 21; the electrode assembly 22 is housed in the receiving cavity, the electrode assembly 22 includes a main body 221 and a tab 222, the main body 221 includes a first end face 2211 and an outer peripheral face 2213, the outer peripheral face 2213 intersects with the first end face 2211 and surrounds the first end face 2211, the tab 222 is located on the first end face 2211, the first end face 2211 faces the first wall 201.

[0096] In this embodiment, the battery cell 20 may include a housing 21, the interior of which has a cavity for accommodating the electrode assembly 22. The housing 21 may be a hollow polyhedral structure for accommodating the electrode assembly 22.

[0097] In some embodiments, the outer casing 21 may be a steel casing, an aluminum casing, a plastic casing (such as a polypropylene casing), a composite metal casing (such as a copper-aluminum composite casing), or an aluminum-plastic film, etc. In some embodiments, the outer casing 21 may be a sealed structure or a non-sealed structure.

[0098] For ease of explanation, this application embodiment uses a cuboid battery cell 20 as an example, that is, the outer casing 21 is approximately cuboid; and, taking the cuboid battery cell 20 as an example, three reference directions are defined: the length direction of the battery cell 20 is direction X, the thickness direction of the battery cell 20 is direction Y, and the height direction of the battery cell 20 is direction Z. Among them, the thickness direction Y, the height direction Z and the length direction X of the battery cell 20 are perpendicular to each other, and the dimension of the thickness direction Y of the battery cell 20 is smaller than the dimension of the length direction X.

[0099] It should be understood that the electrode assembly set 22 in this application embodiment may include at least one electrode assembly 220. Each electrode assembly 220 is a component in the battery cell 20 where an electrochemical reaction occurs. Depending on actual usage requirements, the specific number of electrode assemblies 220 included in the electrode assembly set 22 within the battery cell 20 may be set to one or more. The shape of the electrode assembly set 22 in this application embodiment can be set according to actual application, and all electrode assemblies 220 included in the electrode assembly set 22 generally have the same shape. For example, the electrode assembly 220 may be a cylinder, a cuboid, etc. Furthermore, the external shape of the battery cell 20 may be the same as or different from the shape of the electrode assembly set 22. For example, if the electrode assembly set 22 is a cylindrical structure, the outer shell 21 of the battery cell 20 may also be a cylindrical structure, or it may be a cuboid structure; if the electrode assembly set 22 is a cuboid structure, the outer shell 21 may also generally be a cuboid structure, but this application embodiment is not limited to this. For ease of explanation, as shown in Figures 1 to 3, the embodiments of this application mainly take the cuboid electrode assembly set 22 as an example, and each electrode assembly 220 is also a cuboid as an example for explanation.

[0100] The electrode assembly 22 of this application embodiment may include tabs 222 and a main body 221. Specifically, the electrode assembly 22 may include at least two tabs 222, which may include at least one positive tab 222a and at least one negative tab 222b. Each positive tab 222a may be formed by stacking portions of one or more positive electrode sheets of the electrode assembly 220 that are not coated with a positive active material layer, while the corresponding portions of the positive electrode sheets coated with a positive active material layer may be formed by winding or stacking to form the main body 221 of the electrode assembly 22. Each negative tab 222b may be formed by stacking portions of one or more negative electrode sheets of the electrode assembly 220 that are not coated with a negative active material layer, while the corresponding portions of the negative electrode sheets coated with a negative active material layer may be formed by winding or stacking to form the main body 221 of the electrode assembly 22. That is, the main body 221 of the electrode assembly 22 includes the portion of the positive electrode sheet of all electrode assemblies 220 coated with a positive active material layer and the portion of the negative electrode sheet coated with a negative active material layer.

[0101] In this embodiment, the multiple tabs 222 of the electrode assembly 22 can be located on the same end face of the electrode assembly 22. For example, as shown in Figures 1 to 3, this embodiment mainly takes the example that all the tabs 222 of the electrode assembly 22 are disposed on the first end face 2211 of the main body 221 of the electrode assembly 22, but this embodiment is not limited to this.

[0102] The main body 221 of this embodiment further includes an outer peripheral surface 2213, which intersects with and surrounds the first end face 2211. For example, as shown in Figures 1 to 3, taking the approximately cuboid main body 221 as an example, when the first end face 2211 is provided with a tab 222, the outer peripheral surface 2213 that connects to and surrounds the first end face 2211 may include four surfaces.

[0103] The battery cell 20 of this embodiment may also be provided with electrode terminals 214 on its outer casing 21. The electrode terminals 214 are used to electrically connect with the electrode assembly 22 to output the electrical energy of the battery cell 20. As shown in Figures 1 to 3, the battery cell 20 may include at least two electrode terminals 214, which include at least one positive electrode terminal 214a and at least one negative electrode terminal 214b. Each electrode terminal 214 is used to electrically connect with a corresponding tab 222. For example, each electrode terminal 214 can be electrically connected to the corresponding tab 222 through a current collector 27. For example, the positive tab 222a of the electrode assembly 22 can be connected to the positive electrode terminal 214a through one current collector 27, and the negative tab 222b of the electrode assembly 22 can be connected to the negative electrode terminal 214b through another current collector 27.

[0104] At least two electrode terminals 214 of the battery cell 20 can be disposed on the same wall or different walls of the battery cell 20. For example, the position of the electrode terminals 214 can be set according to the position of the tabs 222 of the electrode assembly 22. For example, as shown in Figures 1 to 3, the embodiment of this application mainly takes the battery cell 20 as having two electrode terminals 214, and the two electrode terminals 214 being disposed on the first wall 201 of the battery cell 20. The first wall 201 is any wall of the outer casing 21, and the first end face 2211 faces the first wall 201 to facilitate the electrical connection between the tabs 222 and the electrode terminals 214.

[0105] Figure 4 shows a schematic diagram of the internal structure of the battery cell 20 according to an embodiment of this application. For example, the battery cell 20 shown in Figure 4 can be a possible implementation of the battery cell 20 shown in Figures 1 and 2. Figure 5 shows a schematic cross-sectional view of the battery cell 20 according to an embodiment of this application. For example, the battery cell 20 shown in Figure 5 can be a cross-sectional view of the battery cell 20 shown in Figure 4. That is, Figure 5 can also be a possible implementation of the battery cell 20 shown in Figures 1 and 2. The cross-section shown in Figure 5 is perpendicular to the length direction X of the battery cell 20. That is, Figure 5 can be a schematic cross-sectional view of the battery cell 20 along the A-A' direction shown in Figure 4. Figure 6 shows another partial schematic cross-sectional view of the battery cell 20 according to an embodiment of this application. For example, the battery cell 20 shown in Figure 6 can be a cross-sectional view of the battery cell 20 shown in Figure 4. The cross-section shown in Figure 6 is perpendicular to the length direction X of the battery cell 20, and the cross-section shown in Figure 6 passes through the electrode terminal 214.

[0106] As shown in Figures 1 to 6, the battery cell 20 of this embodiment further includes a current collector 27, a first insulating film 23, and a second insulating film 26. Specifically, the current collector 27 is used to electrically connect the electrode terminal 214 and the tab 222; the first insulating film 23 covers the outer peripheral surface 2213; the second insulating film 26 includes a relatively bent body portion 261 and an extension portion 262. The body portion 261 is disposed between the current collector 27 and the first wall 201 to isolate the current collector 27 and the first wall 201. The extension portion 262 covers a portion of the outer peripheral surface 2213, and the first insulating film 23 wraps around and fixes the extension portion 262.

[0107] It should be understood that the current collector 27 in this embodiment is used to electrically connect the electrode terminal 214 and the tab 222. For example, the current collector 27 used to electrically connect the positive tab 222a and the positive electrode terminal 214a can be located between the positive tab 222a and the positive electrode terminal 214a; the current collector 27 used to electrically connect the negative tab 222b and the negative electrode terminal 214b can be located between the negative tab 222b and the negative electrode terminal 214b, so as to facilitate the processing and assembly of the battery cell 20.

[0108] The first insulating film 23 of this application embodiment covers the outer peripheral surface 2213, which can effectively isolate the outer peripheral surface 2213 of the electrode assembly 22 from the outer shell 21.

[0109] The second insulating film 26 in this embodiment includes a relatively bent body portion 261 and an extension portion 262. The body portion 261 is disposed between the current collector 27 and the first wall 201, which can isolate the current collector 27 and the first wall 201, and can also be used to isolate the first end face 2211 where the electrode tab 222 is located and the first wall 201. This can reduce the impact of the second insulating film 26 on the electrical connection between the current collector 27 and the electrode tab 222, that is, it can improve the insulation performance between the electrode assembly assembly 22 and the housing 21, and reduce the impact on the electrode assembly assembly 22 and the current collector 27, thereby improving the reliability of the battery cell 20.

[0110] In this embodiment, the extension 262 of the second insulating film 26 covers a portion of the outer peripheral surface 2213. The first insulating film 23 wraps around and fixes the extension 262. The fixation of the second insulating film 26 is achieved simultaneously through the fixation between the first insulating film 23 and the electrode assembly 22, which facilitates processing and improves structural stability.

[0111] In this embodiment, the outer casing 21 includes: a housing 211 having an opening 2111; and a cover plate 212 for covering the opening 2111 to form a receiving cavity. Specifically, the housing 211 is a hollow structure with an opening 2111, and the electrode assembly 22 wrapped with a first insulating film 23 is accommodated within the housing 211 through the opening 2111; the cover plate 212 is used to cover the opening 2111 of the housing 211 to isolate the external environment.

[0112] In some embodiments, the housing 211 may be a hollow structure with an opening 2111 at at least one end, and the shape of the cover plate 212 may be adapted to the shape of the housing 211. The cover plate 212 is used to cover the opening 2111 of the housing 211 so that the housing 21 isolates the internal environment of the battery cell 20 from the external environment. If the housing 211 is a hollow structure with an opening 2111 at one end, the cover plate 212 may be provided as one; or, if the housing 211 is a hollow structure with openings 2111 at both opposite ends, the cover plate 212 may be provided as two, and the two cover plates 212 respectively cover the openings 2111 at both ends of the housing 211. The embodiments of this application are not limited to this.

[0113] The shell 211 in this embodiment can be made of various materials, such as copper, iron, aluminum, steel, aluminum alloy, etc. The cover plate 212 can also be made of various materials, such as copper, iron, aluminum, steel, aluminum alloy, etc. The material of the cover plate 212 can be the same as or different from that of the shell 211.

[0114] In this embodiment, the shell 211 and cover plate 212 are shaped to fit each other. For example, the shell 211 can be an approximate cuboid structure, and the cover plate 212 can be an approximate rectangular plate structure adapted to the shell 211. The cover plate 212 can be any wall of the shell 21. For example, the cover plate 212 can be the wall with the largest area among the multiple walls included in the shell 21, or the wall with the smallest area, or it can be other walls. This embodiment is not limited to these. Alternatively, the cover plate 212 can also have other structures. For example, the cover plate 212 can also be a groove structure with an opening to cover the opening 2111 of the shell 211. This embodiment is not limited to these.

[0115] For ease of explanation, this application mainly takes the hollow structure with one open end of the housing 211 as an example; correspondingly, by setting a cover plate 212 to cover the opening 2111 of the housing 211, for example, the housing 211 and the cover plate 212 can be sealed by welding to form a closed cavity for placing the electrode assembly 22, thereby improving the sealing reliability.

[0116] It should be understood that the relative positional relationship between the various end faces of the main body 221 and the outer shell 21 in this embodiment can be flexibly set according to actual application. For example, the first end face 2211 with the tab 222 can face any wall of the outer shell 21.

[0117] In some embodiments, as shown in Figures 1 to 6, the present application embodiment mainly takes the cover plate 212 including the first wall 201 as an example, that is, the first end face 2211 is disposed facing the cover plate 212, and the electrode terminal 214 is located on the cover plate 212, so as to facilitate processing and installation. For example, during installation, the electrode assembly 22 wrapped with the first insulating film 23 can be placed into the housing 211 through the opening 2111 of the housing 211, and the first end face 2211 of the electrode assembly 22 with the tab 222 is disposed facing the opening 2111, and then the cover plate 212 is closed to cover the opening 2111.

[0118] In some embodiments, as shown in Figures 1 to 6, the second insulating film 26 includes two opposing extensions 262, each covering at least a portion of the two large surfaces 2214 of the outer peripheral surface 2213, where the large surface 2214 is the surface with the largest area of ​​the outer peripheral surface 2213. By configuring the second insulating film 26 with two opposing extensions 262, the second insulating film 26 achieves a relatively symmetrical structure, which improves the stability of the second insulating film 26. Furthermore, each extension 262 covers the large surface 2214 of the outer peripheral surface 2213, facilitating the first insulating film 23 to cover and fix the second insulating film 26, further improving structural stability and reducing the risk of insulation failure of the battery cell 20.

[0119] Figure 7 shows a schematic diagram of the structure of the second insulating film 26 according to an embodiment of this application. For example, Figure 7 can be a top view of the second insulating film 26 in its unfolded state according to an embodiment of this application. As shown in Figure 7, the second insulating film 26 can adopt a sheet-like structure and has two relatively parallel folds 263. By bending the second insulating film 26 along the two folds 263, the main body 261 and two oppositely arranged extensions 262 can be obtained. The main body 261 is disposed between the first wall 201 and the current collecting member 27. By bending the second insulating film 26 through the two preset folds 263, the two extensions 262 can cover the two large surfaces 2214 of the outer peripheral surface 2213. The operation is simple and easy to implement.

[0120] In this embodiment, the battery cell 20 further includes an insulating member 25, which is fixed to the first wall 201 and located between the first wall 201 and the first end face 2211. A first insulating film 23 is fixed to the insulating member 25. The insulating member 25 can be used to isolate the first end face 2211 from the first wall 201. In addition, the first insulating film 23 covering the outer peripheral surface 2213 is fixed to the insulating member 25 to further improve the stability of the various components inside the battery cell 20.

[0121] In some embodiments, the body portion 261 is disposed between the current collector 27 and the insulator 25, such that the second insulating film 26 and the insulator 25 are used together to isolate the electrode assembly assembly 22 from the first wall 201, and to isolate the current collector 27 from the first wall 201, thereby improving the insulation effect inside the battery cell 20.

[0122] In some embodiments, as shown in Figures 4 to 7, the insulating member 25 includes a first electrode lead-out hole 251, and the electrode terminal 214 is connected to the current collector 27 through the first electrode lead-out hole 251 to realize the electrical connection between the electrode terminal 214 and the tab 222, thereby outputting electrical energy.

[0123] In some embodiments, as shown in Figures 4 to 7, the first wall 201 includes a third electrode lead-out hole 2011. The electrode terminal 214 is connected to the current collector 27 through the third electrode lead-out hole 2011. For example, the electrode terminal 214 can pass through the third electrode lead-out hole 2011 and the first electrode lead-out hole 251 in sequence, and then be connected to the current collector 27 to realize the electrical connection between the electrode terminal 214 and the tab 222, thereby outputting electrical energy.

[0124] In some embodiments, as shown in Figures 4 to 7, the body portion 261 includes a second electrode lead-out hole 2611. An electrode terminal 214 and / or a current collector 27 pass through the second electrode lead-out hole 2611 to connect with the current collector 27. For example, the electrode terminal 214 can sequentially pass through the third electrode lead-out hole 2011, the first electrode lead-out hole 251, and the second electrode lead-out hole 2611 to connect with the current collector 27; or, the electrode terminal 214 can sequentially pass through the third electrode lead-out hole 2011 and the first electrode lead-out hole 251, while the current collector 27 passes through the second electrode lead-out hole 2611, so that the electrode terminal 214 is connected with the current collector 27, thereby realizing the electrical connection between the electrode terminal 214 and the tab 222, and thus outputting electrical energy.

[0125] Figure 8 shows a schematic diagram of the current collector 27, the second insulating film 26, and the insulating element 25 in the battery cell 20 of this application embodiment. For example, Figure 8 can be a bottom view of the current collector 27, the second insulating film 26, and the insulating element 25 included in the battery cell 20 as shown in Figures 4 to 6.

[0126] In some embodiments, as shown in Figures 4 to 8, the current collector 27 includes an electrode terminal connection portion 271 for electrical connection with an electrode terminal 214. For example, the electrode terminal 214 passes through a second electrode lead-out hole 2611 and connects to the electrode terminal connection portion 271. As another example, the electrode terminal 214 sequentially passes through a third electrode lead-out hole 2011, a first electrode lead-out hole 251, and a second electrode lead-out hole 2611 to connect to the electrode terminal connection portion 271.

[0127] In some embodiments, unlike Figures 4 to 8, the electrode terminal 214 may pass through the third electrode lead-out hole 2011 and the first electrode lead-out hole 251 in sequence, while the electrode terminal connection portion 271 passes through the second electrode lead-out hole 2611. For example, the electrode terminal connection portion 271 may protrude toward the electrode terminal 214 through the second electrode lead-out hole 2611 so that the electrode terminal 214 is connected to the electrode terminal connection portion 271 of the current collector 27.

[0128] In some embodiments, the electrode terminal 214 may pass through the third electrode lead-out hole 2011 and the first electrode lead-out hole 251 in sequence, and a portion of the electrode terminal 214 is accommodated in the second electrode lead-out hole 2611, and the electrode terminal connection portion 271 is also accommodated in the second electrode lead-out hole 2611, so that the electrode terminal 214 and the electrode terminal connection portion 271 of the current collector 27 are connected in the second electrode lead-out hole 2611, thereby realizing the electrical connection between the electrode terminal 214 and the current collector 27.

[0129] In some embodiments, as shown in Figures 4 to 8, the current collector 27 includes a tab connection portion 272 for electrical connection with a tab 222. The tab connection portion 272 is located between the body portion 261 and the tab 222, that is, the body portion 261 of the second insulating film 26 is located on the side of the tab connection portion 272 of the current collector 27 away from the tab 222, so as to reduce the influence of the second insulating film 26 on the electrical connection between the tab connection portion 272 and the tab 222.

[0130] In some embodiments, the battery cell 20 further includes a pressure relief mechanism 213, which is disposed on the first wall 201, and the body portion 261 further includes a pressure relief hole 2612 corresponding to the pressure relief mechanism 213. Thus, when thermal runaway occurs in the battery cell 20, the pressure relief hole 2612 reduces the obstruction of the second insulating film 26 from the discharge of pollutants from the battery cell 20, allowing the pressure relief mechanism 213 to be activated promptly to quickly discharge pollutants and improve the reliability of the battery cell 20.

[0131] It should be understood that the pressure relief mechanism 213 in this embodiment is actuated when the internal pressure or temperature of the battery cell 20 reaches a predetermined threshold, in order to release the internal pressure or temperature. When the internal pressure or temperature of the battery cell 20 reaches the predetermined threshold, the pressure relief mechanism 213 performs an action or a weak structure provided in the pressure relief mechanism 213 is destroyed, thereby forming an opening or channel for the release of internal pressure or temperature. The threshold design varies depending on the design requirements. The threshold may depend on the materials of one or more of the positive electrode, negative electrode, electrolyte, and separator in the battery cell 20.

[0132] As an example, the pressure relief mechanism 213 can be integrally formed with the first wall 201; or, the pressure relief mechanism 213 can be separately set and connected to the first wall 201.

[0133] The term "actuation" as used in this application refers to the pressure relief mechanism 213 being activated or undergoing a certain state, thereby releasing the internal pressure and temperature of the battery cell 20. The actions of the pressure relief mechanism 213 may include, but are not limited to: movement of components within the pressure relief mechanism 213 to form an exhaust channel, rupture, breakage, tearing, or opening of at least a portion of the pressure relief mechanism 213, etc. When the pressure relief mechanism 213 is actuated, the high-temperature, high-pressure substances inside the battery cell 20 are discharged outwards from the actuated portion as exhaust materials. This method enables pressure and temperature relief of the battery cell 20 under controllable pressure or temperature conditions, thereby preventing potentially more serious accidents.

[0134] The emissions from the battery cell 20 mentioned in this application include, but are not limited to: electrolyte, dissolved or split positive and negative electrode plates, fragments of separators, high-temperature and high-pressure gases generated by the reaction, flames, etc.

[0135] It should be understood that the size and shape of the pressure relief hole 2612 can be set according to the size and shape of the corresponding pressure relief mechanism 213. For example, the shape of the pressure relief hole 2612 can be the same as or similar to the shape of the pressure relief mechanism 213 to facilitate processing. Furthermore, the area of ​​the pressure relief mechanism 213 is usually less than or equal to the area of ​​the pressure relief hole 2612, meaning that the projection of the pressure relief mechanism 213 toward the body portion 261 is usually within the range of the pressure relief hole 2612. This ensures that the pressure relief hole 2612 does not obstruct the pressure relief mechanism 213, thereby reducing the obstruction effect of the pressure relief hole 2612 on emissions when the battery cell 20 experiences thermal runaway, and thus improving the reliability of the battery cell 20.

[0136] In some embodiments, the battery cell 20 further includes an injection structure 215 disposed on the first wall 201, and the body portion 261 further includes an injection hole 2613 disposed corresponding to the injection structure 215. Through the injection hole 2613, the electrolyte can smoothly wet the electrode assembly assembly 22, which facilitates improving the processing efficiency of the battery cell 20.

[0137] It should be understood that the electrolyte injection structure 215 in this embodiment may include an injection through-hole disposed on the first wall 201 and a sealing structure for sealing the injection through-hole. Electrolyte is injected into the battery cell 20 through the injection through-hole disposed on the first wall 201 and the injection hole 2613 of the body portion 261, and the injection through-hole of the first wall 201 is sealed by the sealing structure to reduce the risk of electrolyte leakage and improve the reliability and stability of the battery cell 20.

[0138] It should be understood that the dimensions of the extension 262 in this embodiment can be set according to actual applications. For example, as shown in Figures 4 to 8, along the thickness direction of the first end face 2211, the range of the ratio of the length D1 of the extension 262 covering the outer peripheral surface 2213 to the length D2 of the outer peripheral surface 2213 is [0.08, 0.25]. For example, taking the thickness direction of the first end face 2211 as the height direction Z of the battery cell 20, setting the ratio of the length D1 of the extension 262 covering the outer peripheral surface 2213 to the length D2 of the outer peripheral surface 2213 to be greater than or equal to 0.08 can increase the area of ​​the outer peripheral surface 2213 covered by the extension 262, and can also increase the area of ​​the extension 262 covered by the first insulating film 23, improve the stability between the extension 262 and the first insulating film 23, and thus improve the structural stability of the battery cell 20. The ratio of the length D1 of the extension 262 covering the outer peripheral surface 2213 to the length D2 of the outer peripheral surface 2213 is less than or equal to 0.25, which can limit the area of ​​the extension 262. Considering that the first insulating film 23 can cover the outer peripheral surface 2213, appropriately limiting the area of ​​the extension 262 can reduce the area of ​​overlap between the extension 262 and the first insulating film 23, reduce the space occupied by the extension 262 and the first insulating film 23 on the surface of the outer peripheral surface 2213, improve the space utilization of the battery cell 20, reduce the weight of the battery cell, and thus improve the energy density of the battery cell 20.

[0139] Figure 9 shows another partial cross-sectional view of the battery cell 20 according to an embodiment of the present application. For example, the battery cell 20 shown in Figure 9 can be another possible partial cross-sectional view of the battery cell 20 shown in Figure 4, and the cross-section shown in Figure 9 is perpendicular to the length direction X of the battery cell 20, and the cross-section shown in Figure 9 passes through the electrode terminal 214.

[0140] In some embodiments, as shown in FIG9, the battery cell further includes a third insulating film 28, which includes a first region 281 and a second region 282 that are bent relative to each other. The first region 281 is bonded to the tab connection portion 272, and the second region 282 is bonded to and covers a portion of the outer peripheral surface 2213. A second insulating film 26 covers the third insulating film 28. The third insulating film 28 can isolate the tab connection portion 272 from the first wall 201, thereby improving the insulation reliability between the tab connection portion 272 and the first wall 201.

[0141] In some embodiments, the first region 281 can also be used to adhere to and cover the surface of the tab 222 facing the first wall 201 that is not covered by the current collector 27. For example, the first region 281 can cover the edge region of the tab 222 that is not covered by the current collector 27 to isolate this part of the tab 222 from the first wall 201, thereby further improving the internal insulation reliability of the battery cell 20.

[0142] In some embodiments, the first region 281 can also be used to adhere to and cover a portion of the first end face 2211. For example, the first region 281 can cover the outer edge region of the first end face 2211 to isolate the portion of the first end face 2211 from the first wall 201, thereby further improving the internal insulation reliability of the battery cell 20.

[0143] In some embodiments, the first region 281 of the third insulating film 28 is located between the first end face 2211 and the body portion 261 of the second insulating film 26. By bending the third insulating film 28, the second region 282 of the third insulating film 28 is adhered to and covers a portion of the outer peripheral surface 2213. This can improve the stability and reliability of the third insulating film 28, thereby reducing the risk of insulation failure between the tab 222 and the first wall 201.

[0144] In some embodiments, along the thickness direction of the first wall 201, the length of the extension 262 covering the outer peripheral surface 2213 is greater than the length of the second region 282 covering the outer peripheral surface 2213, so that the third insulating film 28 is further fixed by the second insulating film 26, thereby improving the stability and reliability of the third insulating film 28. As shown in FIG9, taking the thickness direction of the first wall 201 as the height direction Z of the battery cell 20 as an example, if the length of the extension 262 covering the outer peripheral surface 2213 is greater than the length of the second region 282 covering the outer peripheral surface 2213, then the end of the extension 262 away from the first wall 201 exceeds the end of the second region 282 away from the first wall 201, so that the extension 262 can cover the entire area of ​​the second region 282, further fixing the second region 282.

[0145] In some embodiments, the melting point of the third insulating film 28 is greater than that of the second insulating film 26. Thus, during the use of the battery cell 20, when the temperature of the battery cell assembly 22 rises, the third insulating film 28 is less likely to be damaged than the second insulating film 26, which can improve the insulation reliability between the tab 222 and the first wall 201 and reduce the risk of insulation failure.

[0146] It should be understood that the melting point in the embodiments of this application refers to the temperature at which the material is damaged. For example, the melting point of the third insulating film 28 refers to the temperature at which the third insulating film 28 is damaged or melted.

[0147] It should be understood that the material of the third insulating film 28 can be set according to the actual application. For example, the material of the third insulating film 28 may include polyimide (PI) to make the third insulating film 28 resistant to high temperatures and easy to implement.

[0148] It should be understood that each electrode assembly 220 included in the electrode assembly set 22 of this application embodiment can be a wound electrode assembly or a stacked electrode assembly, to suit different application scenarios. Furthermore, the multiple electrode assemblies 220 included in the electrode assembly set 22 are generally of the same type; for example, they can all be wound electrode assemblies or stacked electrode assemblies.

[0149] The electrode assembly 220 of any embodiment of this application will now be described with reference to the accompanying drawings.

[0150] In some embodiments, the electrode assembly 220 of this application can be a wound electrode assembly. Specifically, the electrode assembly 220 may include a positive electrode and a negative electrode, which are wound together around a winding shaft to form the wound electrode assembly 220.

[0151] In some embodiments, the electrode assembly 220 of this application can be a stacked electrode assembly, and the specific structure of the stacked electrode assembly can be set according to the actual application. FIG10 shows a cross-sectional schematic diagram of the electrode assembly 220 of this application, wherein the cross-section shown in FIG10 is perpendicular to the height direction of the battery cell 20, and the electrode assembly 220 shown in FIG10 can be any one of the electrode assembly 220 shown in FIG1 to FIG3 as a possible implementation. As shown in FIG10, the portion of the electrode assembly 220 corresponding to the main body 221 includes a plurality of first electrode sheets 223 and a plurality of second electrode sheets 224 with opposite polarities. The plurality of first electrode sheets 223 and the plurality of second electrode sheets 224 are alternately stacked along a first direction. For example, here the first direction is the thickness direction Y of the battery cell 20, thereby forming a stacked electrode assembly.

[0152] Figure 11 shows a cross-sectional schematic diagram of an electrode assembly 220 according to another embodiment of this application. The cross-section shown in Figure 11 is perpendicular to the height direction of the battery cell 20. The electrode assembly 220 shown in Figure 11 can be another possible implementation of any one of the electrode assembly 220s shown in Figures 1 to 3. As shown in Figure 11, the portion of the electrode assembly 220 corresponding to the main body 221 includes a first electrode 223 with opposite polarity and a plurality of second electrode 224. The first electrode 223 includes at least one bent section 2231 and a plurality of stacked sections 2232. The bent section 2231 is used to connect two adjacent stacked sections 2232. The plurality of stacked sections 2232 and the plurality of second electrode 224 are alternately stacked along a first direction. For example, here the first direction is the thickness direction Y of the battery cell 20, thereby forming a stacked electrode assembly.

[0153] It should be understood that the first electrode 223 and the second electrode 224 in this embodiment are electrodes with opposite polarities. For example, if the first electrode 223 is a positive electrode, then the second electrode 224 is a negative electrode; conversely, if the first electrode 223 is a negative electrode, then the second electrode 224 is a positive electrode. For example, as shown in Figures 10 and 11, this embodiment uses the first electrode 223 as a negative electrode and the second electrode 224 as a positive electrode to reduce the risk of metal deposition in the electrode assembly 220 and improve the electrical performance of the battery cell 20.

[0154] In this embodiment, the electrode assembly 220 further includes an isolator 225, which is disposed between the positive electrode and the negative electrode to isolate the positive electrode and the negative electrode.

[0155] When the electrode assembly 22 includes stacked electrode assemblies 220 as shown in Figures 10 and 11, the first insulating film 23 can also be used to fix the electrode assembly 22 to improve its stability. Especially when the electrode assembly 22 includes multiple electrode assemblies 220, the first insulating film 23 surrounds the outer peripheral surface 2213 of the electrode assembly 22. This first insulating film 23 can increase structural stability, reduce misalignment and movement between the multiple stacked electrode sheets, and thus improve the performance of the electrode assembly 22.

[0156] In some embodiments, for the stacked electrode assembly shown in Figures 10 and 11, the electrode assembly 220 may further include a fixing structure 2203 to fix the electrode assembly 220. Figures 12 and 13 respectively show schematic diagrams of the electrode assembly 220 from different angles according to embodiments of the present application. The electrode assembly 220 shown in Figures 12 and 13 can be the electrode assembly 220 shown in Figure 10 or Figure 11. Specifically, Figure 12 shows a front view of the electrode assembly 220 according to an embodiment of the present application; Figure 13 shows a bottom view of the electrode assembly 220 according to an embodiment of the present application.

[0157] As shown in Figures 12 and 13, the electrode assembly 220 includes a first surface 2201 and a second surface 2202 disposed opposite to each other along the thickness direction of the electrode assembly 220. The electrode assembly 220 also includes a plurality of fixing structures 2203 disposed at intervals. Each of the plurality of fixing structures 2203 extends from the edge of the first surface 2201 along the thickness direction of the electrode assembly 220 to the edge of the second surface 2202. A second insulating film 26 covers the plurality of fixing structures 2203. For a stacked electrode assembly, by providing a plurality of fixing structures 2203, the plurality of electrodes of the electrode assembly 220 can be fixed to improve the stability of the electrode assembly 220. Furthermore, in this embodiment of the application, the first insulating film 23 and the second insulating film 26 are at least disposed on the outer peripheral surface 2213 of the main body 221 of the electrode assembly 22, that is, disposed on the outside of the plurality of fixing structures 2203 of the main body 221, and cover at least a portion of the area of ​​at least one of the fixing structures 2203. This can reduce the movement and misalignment between the plurality of electrode assemblies 220, thereby further improving the stability of the electrode assembly 22.

[0158] In some embodiments, at least one fixing structure 2203 may be provided in different regions of the electrode assembly 220. For example, as shown in Figures 12 and 13, take the end faces of the electrode assembly 220 used to connect the first surface 2201 and the second surface 2202 as examples. Considering that the fixing structure 2203 is an insulating material, the end face of the electrode assembly 220 with tabs 222 may not have any fixing structure 2203 or may have a small number of fixing structures 2203 to reduce the impact on the tabs 222. For example, in Figures 12 and 13, taking the first end face 2211 with tabs 222 as an example with only one fixing structure 2203, the body portion 261 of the second insulating film 26 used to cover the first end face 2211 is at least provided on the outside of the fixing structure 2203 and covers the area of ​​the fixing structure 2203 located on the first end face 2211. For the end face of the electrode assembly 220 that does not have tabs 222, a certain number of fixing structures 2203 can be provided according to the size of the end face. For example, in Figures 12 and 13, three fixing structures 2203 are provided for each end face, but the embodiments of this application are not limited to this.

[0159] The first insulating film 23 disposed on a portion of the outer surface of the main body 221 according to an embodiment of this application will now be described with reference to the accompanying drawings.

[0160] It should be understood that the first insulating film 23 in this embodiment can be disposed on the surface of the main body 221 in various ways. For example, the first insulating film 23 can be pasted on a portion of the surface of the main body 221. For example, the first insulating film 23 can be pasted on and cover the outer peripheral surface 2213 of the main body 221 to effectively isolate the electrode assembly assembly 22 from the housing 21. Furthermore, the first insulating film 23 does not need to be fixed by heat fusion, reducing processing steps and facilitating the processing of the battery cell 20, thereby improving the processing efficiency of the battery cell 20.

[0161] In some embodiments, the first insulating film 23 includes at least one insulating sheet 231, and the first insulating film 23 is folded and adhered to the outer peripheral surface 2213. Compared with the method of covering the outside of the electrode assembly assembly 22 with materials such as heat-shrink film, the first insulating film 23 in this embodiment adopts a sheet structure. At least one insulating sheet 231 can be wrapped and adhered to the outer peripheral surface 2213 by folding. The processing method is simple and can improve processing efficiency. In addition, the first insulating film 23 can be more tightly attached to the main body 221 of the electrode assembly assembly 22, which can improve the space utilization of the battery cell 20.

[0162] Figure 14 shows a top view of the electrode assembly 22 wrapped with a first insulating film 23 according to an embodiment of the present application. For example, Figure 14 can be a possible way for the first insulating film 23 to wrap the outer peripheral surface 2213 of the electrode assembly 22 according to an embodiment of the present application.

[0163] In some embodiments, as shown in FIG14, the first insulating film 23 may include an insulating sheet 231 surrounding the outer peripheral surface 2213, such that the starting end and the ending end of the insulating sheet 231 are stacked and fixed on either end face of the outer peripheral surface 2213. For example, FIG14 shows the starting end and the ending end of the insulating sheet 231 stacked on the side surface 2215 of the outer peripheral surface 2213, where the side surface 2215 is the surface with the smallest area included in the outer peripheral surface 2213. Alternatively, unlike FIG14, the starting end and the ending end of the insulating sheet 231 may also be stacked on other end faces of the outer peripheral surface 2213; the embodiments of this application are not limited to this.

[0164] In some embodiments, as shown in FIG14, taking the example of the starting end and the ending end of the insulating sheet 231 overlapping each other on the side surface 2215 of the outer peripheral surface 2213, when the electrode assembly assembly 22 includes multiple electrode assemblies 220, the overlapping position of the starting end and the ending end can be located in any region of the side surface 2215 of the outer peripheral surface 2213, and the size of the overlapping region can also be set according to the actual application. For example, the overlapping region of the starting end and the ending end of the insulating sheet 231 can cover the side surface of any one or more electrode assemblies 220 in the electrode assembly assembly 22; or, as shown in FIG14, the overlapping region of the starting end and the ending end of the insulating sheet 231 can cover the middle region of any two electrode assemblies 220 in the electrode assembly assembly 22. The embodiments of this application are not limited to this.

[0165] Figures 15 to 17 show top views of electrode assembly 22 wrapped with a first insulating film 23 in several other embodiments of this application. For example, Figures 15 to 17 can be several other possible ways in which the first insulating film 23 wraps the outer peripheral surface 2213 of the electrode assembly 22 in the embodiments of this application.

[0166] In some embodiments, the first insulating film 23 may further include a plurality of insulating sheets 231, which are interconnected to surround the outer peripheral surface 2213. The arrangement of multiple insulating sheets 231 surrounding the outer peripheral surface 2213 can improve the processing flexibility of the battery cell 20, making it suitable for different application scenarios and different types of battery cells 20.

[0167] It should be understood that when the first insulating film 23 includes multiple insulating sheets 231, the position of each insulating sheet 231 can be set according to the actual application.

[0168] For example, as shown in Figures 15 to 17, the first insulating film 23 includes two insulating sheets 231. The two insulating sheets 231 respectively cover the two large surfaces 2214 of the outer peripheral surface 2213 and overlap and adhere to the two side surfaces 2215 of the outer peripheral surface 2213 to cover the outer peripheral surface 2213. The area of ​​the side surfaces 2215 of the outer peripheral surface 2213 is smaller than the area of ​​the large surfaces 2214 of the outer peripheral surface 2213. The relatively complete insulating sheets 231 are provided on the two large surfaces 2214 of the outer peripheral surface 2213, while the overlapping area of ​​the two insulating sheets 231 is provided on the two side surfaces 2215 of the outer peripheral surface 2213. This simplifies the processing operation, improves processing efficiency, and enhances structural stability.

[0169] It should be understood that the position and size of the overlapping area of ​​the two insulating sheets 231 included in the first insulating film 23 on the two sides 2215 of the outer peripheral surface 2213 can be set according to the actual application.

[0170] For example, as shown in Figures 15 to 17, the electrode assembly 22 includes a first electrode assembly 2201 and a second electrode assembly 2202. An insulating sheet 231, which is attached to the side of the outer peripheral surface of the first electrode assembly 2201, is attached to the side of the outer peripheral surface of the second electrode assembly 2202 to improve structural stability and reduce the risk of insulation failure of the first insulating film 23.

[0171] Specifically, as shown in Figures 15 to 17, the electrode assembly 22 includes a first electrode assembly 2201 and a second electrode assembly 2202. The first electrode assembly 2201 has one large surface 2214 of its outer peripheral surface 2213, and the second electrode assembly 2202 has another large surface 2214 of its outer peripheral surface 2213. Each side surface 2215 of the outer peripheral surface 2213 includes both a side surface of the first electrode assembly 2201 and a side surface of the second electrode assembly 2202. Correspondingly, the first insulating film 23 includes two insulating sheets 231, for example, the two insulating sheets 2311 being a first insulating sheet 2311 and a second insulating sheet 2312. The first insulating sheet 2311 is used to adhere to one large surface 2214 of the outer peripheral surface 2213 of the first electrode assembly 2201, and the second insulating sheet 2312 is used to adhere to the other large surface 2214 of the outer peripheral surface 2213 of the second electrode assembly 2202.

[0172] Furthermore, the insulating sheet 231, which is bonded to the side of the outer peripheral surface of the first electrode assembly 2201, is bonded to the side of the outer peripheral surface of the second electrode assembly 2202. That is, the first insulating sheet 2311 is also bonded to the area of ​​the first electrode assembly 2201 and at least a portion of the area of ​​the second electrode assembly 2202 on the side surface 2215 of the outer peripheral surface 2213. That is, on each side surface 2215 of the outer peripheral surface 2213, the first insulating sheet 2311 can extend from the area of ​​the first electrode assembly 2201 to the area of ​​the second electrode assembly 2202.

[0173] As shown in Figure 15, when the first insulating sheet 2311 covers the area of ​​the first electrode assembly 2201 and at least a portion of the area of ​​the second electrode assembly 2202 on each side 2215 of the outer peripheral surface 2213, the second insulating sheet 2312 may only cover at least a portion of the area of ​​the second electrode assembly 2202 on each side 2215 of the outer peripheral surface 2213, without covering the area of ​​the first electrode assembly 2201 on each side 2215 of the outer peripheral surface 2213. In this case, the second insulating sheet 2312 covers the first insulating sheet 2311 on each side 2215 of the outer peripheral surface 2213.

[0174] As shown in Figure 16, unlike Figure 15, on each side 2215 of the outer peripheral surface 2213, the first insulating sheet 2311 covers the second insulating sheet 2312.

[0175] As shown in Figure 17, when the first insulating sheet 2311 covers the area of ​​the first electrode assembly 2201 and at least a portion of the area of ​​the second electrode assembly 2202 on each side 2215 of the outer peripheral surface 2213, the second insulating sheet 2312 can cover the area of ​​the second electrode assembly 2202 and at least a portion of the area of ​​the first electrode assembly 2201 in the side 2215 of the outer peripheral surface 2213, so as to increase the size of the overlapping area between the two insulating sheets 231 and improve the structural stability and insulation effect.

[0176] It should be understood that the overlapping areas of the two insulating sheets 231 on the two sides 2215 of the outer peripheral surface 2213 may be in the same or different positions. For example, as shown in Figures 15 to 17, the overlapping areas of the two insulating sheets 231 on the two sides 2215 of the outer peripheral surface 2213 may be in exactly the same position, so that the electrode assembly 22 covering the first insulating film 23 has a symmetrical structure, which is convenient for processing and can improve structural stability.

[0177] The above description, in conjunction with the accompanying drawings, describes how the first insulating film 23 covers the outer peripheral surface 2213 of the present application embodiment. The following description, in conjunction with the accompanying drawings, describes how the first insulating film 23 covers other areas of the main body 221 of the present application embodiment.

[0178] In some embodiments, the main body 221 further includes a second end face 2212 opposite to the first end face 2211, an outer peripheral surface 2213 connecting the first end face 2211 and the second end face 2212, and a first insulating film 23 covering at least a portion of the second end face 2212 to isolate the second end face 2212 from the outer casing 21.

[0179] In some embodiments, as shown in Figures 4 and 5, the first insulating film 23 can cover the entire area of ​​the second end face 2212 to isolate the second end face 2212 from the outer casing 21.

[0180] In some embodiments, unlike Figures 4 and 5, the first insulating film 23 may also cover a local area of ​​the second end face 2212.

[0181] Figure 18 shows a cross-sectional schematic diagram of the battery cell 20 according to an embodiment of this application. For example, the battery cell 20 shown in Figure 18 can be another possible implementation of the battery cell 20 shown in Figures 1 and 2, and the cross-section shown in Figure 18 is perpendicular to the length direction X of the battery cell 20. Figure 19 shows a partial cross-sectional schematic diagram of the battery cell 20 according to another embodiment of this application. For example, Figure 19 can be a partial enlarged view of the area near the lower separator 24 in Figure 18.

[0182] In some embodiments, as shown in Figures 18 and 19, a first insulating film 23 is adhered to and covers the edge region 22122 of the second end face 2212. Exemplarily, the first insulating film 23 includes a first portion 233 and a second portion 234 that are bent relative to each other. The first portion 233 extends along the height direction Z of the battery cell 20 and covers the entire area of ​​the outer peripheral surface 2213. The second portion 234 is bent relative to the first portion 233 and covers the edge region 22122 of the second end face 2212.

[0183] As shown in Figures 18 and 19, the first portion 233 and the second portion 234 of the first insulating film 23 are bent relative to each other. When the first insulating film 23 is pasted, the first insulating film 23 can be wrapped around the outer peripheral surface 2213 so that the first portion 233 of the first insulating film 23 covers the entire area of ​​the outer peripheral surface 2213 to isolate the outer peripheral surface 2213 of the main body 221 and the outer shell 21; then the portion exceeding the outer peripheral surface 2213 is bent to the second end face 2212 so that the second portion 234 of the first insulating film 23 covers the edge area 22122 of the second end face 2212.

[0184] In some embodiments, the battery cell 20 further includes a separator 24, which is adhered to and covers the area of ​​the second end face 2212 not covered by the first insulating film 23, and the separator 24 covers the first insulating film 23. In this embodiment, the separator 24 is adhered to and covers the area of ​​the second end face 2212 not covered by the first insulating film 23, that is, the separator 24 is at least located in the area of ​​the second end face 2212 not covered by the first insulating film 23; furthermore, the separator 24 may also cover the area of ​​the second end face 2212 covered by the first insulating film 23, and the separator 24 covers the first insulating film 23, that is, the first insulating film 23 on the surface of the second end face 2212 is located between the separator 24 and the second end face.

[0185] In this embodiment, the first insulating film 23 covers a portion, rather than the entire, area of ​​the second end face 2212 of the main body 221, which reduces the weight and space occupied by the first insulating film 23, thereby reducing the weight of the battery cell 20 and improving the space utilization of the battery cell 20. At the same time, the separator 24 with adhesive is pasted on at least a portion of the second end face 2212, and the separator 24 covers at least a portion of the first insulating film 23 located on the second end face 2212, so that the separator 24 can be used together with the first insulating film 23 to isolate the second end face 2212 of the electrode assembly 22 and the outer shell 21. Furthermore, the separator 24 can be fixed by adhesive, which facilitates processing and can also improve the processing efficiency of the battery cell 20.

[0186] Figure 20 shows a schematic diagram of the second end face 2212 of the main body 221 with the first insulating film 23 pasted thereon according to an embodiment of this application. In some embodiments, as shown in Figure 20, the second end face 2212 includes a middle region 22121 and an edge region 22122 surrounding the middle region 22121. The first insulating film 23 covers the edge region 22122 of the second end face 2212 but does not cover the middle region 22121 of the second end face 2212. That is, the middle region 22121 of the second end face 2212 is the area on the second end face 2212 that is not covered by the first insulating film 23, and the edge region 22122 of the second end face 2212 is the area on the second end face 2212 covered by the first insulating film 23. The first insulating film 23 only covers a partial area of ​​the second end face 2212. The second end face 2212 can be isolated from the outer casing 21 by the separator 24. It can also reduce the coverage area of ​​the first insulating film 23, reduce weight, and increase the energy density of the battery cell 20.

[0187] In some embodiments, the shape and size of the intermediate region 22121 of the second end face 2212 can be set according to the actual application. For example, the shape of the region 22121 of the second end face 2212 can be the same as that of the second end face 2212. The edge region 22122 of the second end face 2212 is the region of the second end face 2212 other than the intermediate region 22121, and the edge region 22122 of the second end face 2212 surrounds the intermediate region 22121 of the second end face 2212.

[0188] As shown in Figures 18 to 20, the first portion 233 of the first insulating film 23 covers the outer peripheral surface 2213. The first insulating film 23 is bent at the intersection of the outer peripheral surface 2213 and the second end surface 2212, so that the second portion 234 is bent to the second end surface 2212, so that the second portion 234 of the first insulating film 23 covers the edge region 22122 of the second end surface 2212 and exposes the middle region 22121 of the second end surface 2212.

[0189] In some embodiments, the first insulating film 23 is bonded to the insulating member 25, thereby fixing the insulating member 25 and the first insulating film 23 to each other and further improving the stability of the internal components of the battery cell 20. As shown in Figures 18 to 20, along a direction perpendicular to the first end face 2211, the edge of the first portion 233 facing the cover plate 212 extends beyond the first end face 2211, so that the first portion 233 is bonded and fixed to the insulating member 25. For example, taking the direction perpendicular to the first end face 2211 as the height direction Z of the battery cell 20, in this height direction Z, the upper edge of the first portion 233 extends beyond the first end face 2211 and can extend to the insulating member 25, so that the edge of the first portion 233 can be bonded and fixed to the insulating member 25, which can further improve the insulation performance and the structural stability of the battery cell 20. Furthermore, since the first insulating film 23 has an adhesive, no additional fixing method such as heat fusion is required between the first insulating film 23 and the insulating member 25, which can improve processing efficiency.

[0190] It should be understood that the dimensions of the first insulating film 23 in this embodiment can be set according to actual applications. For example, the thickness of the first insulating film 23 can range from 35 μm to 80 μm. Setting the thickness of the first insulating film 23 to be greater than or equal to 35 μm makes it less prone to damage, which can improve the reliability and insulation performance of the first insulating film 23. At the same time, setting the thickness of the first insulating film 23 to be less than or equal to 80 μm, while ensuring that the strength of the first insulating film 23 meets the design requirements, can reduce the space occupied by the first insulating film 23 and increase the energy density of the battery cell 20.

[0191] Furthermore, the thickness of the first insulating film 23 can also be in the range of [40um, 55um], in order to balance the relationship between the structural strength of the first insulating film 23 and the energy density of the battery cell 20.

[0192] In some embodiments, the thickness of the first insulating film 23 may also be other values. For example, the thickness of the first insulating film 23 may also be any of the following values ​​or between any two of the following values: 35μm, 38μm, 40μm, 43μm, 45μm, 48μm, 50μm, 53μm, 55μm, 58μm, 60μm, 63μm, 65μm, 68μm, 70μm, 73μm, 75μm, 78μm, and 80μm.

[0193] It should be understood that the material of the first insulating film 23 in this embodiment can be any insulating material to suit different application scenarios. For example, the material of the first insulating film 23 includes a blue film, that is, the first insulating film 23 can be a blue film with an adhesive layer. Compared with the original use of a mylar film to wrap the electrode assembly 22, this blue film is thinner, and its structural strength and insulation performance can still meet the design requirements. The thinner blue film can reduce the space occupied and increase the energy density of the battery cell 20.

[0194] In some embodiments, the material of the blue film mainly includes polyethylene terephthalate (PET) so that the blue film is suitable for battery cells 20 with different chemical systems, making it easy to process and implement.

[0195] The separator 24 of the present application embodiment will now be described with reference to the accompanying drawings.

[0196] It should be understood that the separator 24 in the embodiments of this application can be used to elevate the electrode assembly 22 to reduce the impact of the rounded corners of the housing 21 on the internal electrode assembly 22.

[0197] In some embodiments, the housing 21 includes an intersecting second wall 202 and a third wall 203 connected by a fillet 204, with the second end face 2212 facing the third wall 203. The thickness T of the separator 24 is greater than or equal to the radius R of the fillet 204 to elevate the electrode assembly 22 and reduce interference at the edge portion of the electrode assembly 22 of the fillet 204.

[0198] As shown in Figure 19, taking the second wall 202 as any side wall of the housing 211 as an example, the third wall 203 is the bottom wall 2112 of the housing 211, and the partition 24 is disposed facing the bottom wall 2112 of the housing 211. When the thickness T of the partition 24 is greater than or equal to the radius R of the fillet 204, and the electrode assembly 22 is disposed above the partition 24, the approximately right-angled corner region of the electrode assembly 22 extends beyond the region of the fillet 204. For example, this corner region can be the intersection of the second end face 2212 and the outer peripheral face 2213 of the main body 221. Therefore, the influence of the fillet 204 on the electrode assembly 22 can be reduced, and the performance of the electrode assembly 22 can be improved.

[0199] In some embodiments, the thickness T of the separator 24 can be set within a range according to the actual application. For example, the thickness T of the separator 24 is related to the radius R of the fillet 204.

[0200] In some embodiments, the thickness T of the separator 24 ranges from [0.25 mm to 0.8 mm]. Setting the thickness T of the separator 24 to be greater than or equal to 0.25 mm elevates the electrode assembly 22 and improves the structural strength of the separator 24. Setting the thickness T of the separator 24 to be less than or equal to 0.8 mm reduces the space occupied by the separator 24 and increases the energy density of the battery cell 20.

[0201] Furthermore, the thickness T of the separator 24 can also be in the range of [0.3mm, 0.5mm], in order to balance the structural strength of the separator 24 and the energy density of the battery cell 20.

[0202] In some embodiments, the thickness T of the separator 24 may also be other values. For example, the thickness T of the separator 24 may also be any of the following values ​​or between any two of the following values: 0.25mm, 0.28mm, 0.3mm, 0.33mm, 0.35mm, 0.38mm, 0.4mm, 0.43mm, 0.45mm, 0.48mm, 0.5mm, 0.53mm, 0.55mm, 0.58mm, 0.6mm, 0.63mm, 0.65mm, 0.68mm, 0.7mm, 0.73mm, 0.75mm, 0.78mm, and 0.8mm.

[0203] Figure 21 shows a schematic diagram of the internal structure of a battery cell 20 according to another embodiment of this application. For example, the battery cell 20 shown in Figure 21 can be another possible implementation of the battery cell 20 shown in Figures 1 and 2. Figure 22 shows a top view of a separator 24 according to an embodiment of this application. For example, Figure 22 can be a schematic diagram of the surface of the separator 24 facing the second end face 2212. Figure 23 shows a bottom view of an electrode assembly 22 with the separator 24 and the first insulating film 23 attached according to an embodiment of this application. For example, Figure 23 can be a schematic diagram of the second end face 2212 with the separator 24 and the first insulating film 23 attached.

[0204] In some embodiments, the surface of the middle region 241 of the separator 24 facing the second end face 2212 is planar. By ensuring that at least the surface of the middle region 241 of the separator 24 facing the second end face 2212 is planar, the stability between the separator 24 and the electrode assembly 22 to which the first insulating film 23 is adhered can be improved. Furthermore, the middle region 241 of the separator 24 may also have an adhesive to facilitate the adhesion of the separator 24 to the second end face 2212, thereby improving the stability and insulation performance of the separator 24.

[0205] As shown in Figures 21 to 23, the specific shape and size of the middle region 241 of the separator 24 can be set according to the actual application. For example, the shape of the middle region 241 of the separator 24 can be consistent with or similar to the outline of the separator 24.

[0206] In some embodiments, an adhesive is provided on the entire surface of the separator 24 facing the second end face 2212 to further improve the connection reliability between the separator 24 and the second end face 2212, thereby improving the insulation effect of the separator 24.

[0207] It should be understood that the shape of the separator 24 in this application embodiment can be set according to actual application. For example, as shown in Figures 18 and 19, the surface of the separator 24 facing the second end face 2212 can be a plane or a near-plane. For example, the separator 24 can be a flat plate structure, which is convenient for processing and allows the second end face 2212 to fit tightly with the surface of the separator 24 facing the second end face 2212, thereby improving structural stability. Furthermore, when the surface of the separator 24 facing the second end face 2212 can be a plane or a near-plane, adhesive can be provided on the entire area of ​​the surface of the separator 24 facing the second end face 2212, or only the surface of the middle region 241 of the separator 24 facing the second end face 2212 can be provided with adhesive. This application embodiment is not limited to this.

[0208] For example, unlike those shown in Figures 18 and 19, a portion of the surface of the separator 24 facing the second end face 2212 can be planar, while another portion can be non-planar. This application embodiment is not limited to this.

[0209] In some embodiments, as shown in Figures 21 to 23, the edge region 242 of the separator 24 includes a curved portion 2421. The curved portion 2421 includes a protruding structure 24211 protruding toward the second end face 2212 and a recessed structure 24212 protruding away from the second end face 2212. The edge region 242 of the separator 24 is the portion of the separator 24 excluding the middle region 241, and the edge region 242 surrounds the middle region 241 of the separator 24.

[0210] The surface of the middle region 241 of the separator 24 facing the second end face 2212 is flat, which can improve the structural stability between the separator 24 and the electrode assembly 22. A curved portion 2421 is provided in the edge region 242 of the separator 24, so that there is more gap between the separator 24 and the second end face 2212. This facilitates the flow of electrolyte from the uneven gaps of the curved portion 2421 into the area of ​​the second end face 2212, improving the wetting performance of the electrode assembly 22 and enhancing the electrical performance of the battery cell 20.

[0211] That is, the edge region 242 of the separator 24 is at least partially set to a wavy shape.

[0212] It should be understood that the number, size, and position of the curved portions 2421 included in the edge region 242 of the separator 24 in the embodiments of this application can be set according to the actual application.

[0213] In some embodiments, the edge region 242 of the separator 24 includes two curved portions 2421 disposed opposite to each other along the width direction of the second end face 2212. The width direction of the second end face 2212 is the direction in which the size of the second end face 2212 is relatively small; for example, the size of the second end face 2212 in the width direction is smaller than its size in the length direction. For example, as shown in Figures 21 to 23, taking the width direction of the second end face 2212 as the width direction Y of the battery cell 20 as an example, if the edge region 242 of the separator 24 includes two oppositely disposed curved portions 2421, then each curved portion 2421 extends along the length direction of the second end face 2212, that is, along the length direction X of the battery cell 20. Therefore, the length of each curved portion 2421 is relatively large, resulting in more gaps between the separator 24 and the second end face 2212, which is more conducive to electrolyte wetting; and the symmetrical distribution of the two curved portions 2421 can improve structural stability.

[0214] In some embodiments, the portion of the edge region 242 of the separator 24 other than the curved portion 2421 is a flat portion 2422, and the surface of the flat portion 2422 facing the second end face 2212 is flat. As shown in Figures 21 to 23, the flat portion 2422 can further increase the stability and insulation between the separator 24 and the electrode assembly 22.

[0215] Alternatively, the edge region 242 of the separator 24 may not have a flat portion 2422. For example, the entire edge region 242 of the separator 24 may be a curved portion 2421 to improve the efficiency of electrolyte wetting of the electrode assembly 22.

[0216] In some embodiments, the surface of the bent portion 2421 facing the second end face 2212 may also be provided with an adhesive, so that the protruding structure 24211 of the bent portion 2421 facing the second end face 2212 can be bonded to the second end face 2212, thereby further improving the stability and insulation between the separator 24 and the electrode assembly 22.

[0217] It should be understood that in this embodiment, both the separator 24 and the first insulating film 23 can be adhered to the second end face 2212 using an adhesive. The materials of the adhesive for the separator 24 and the adhesive for the first insulating film 23 can be set according to the actual application. For example, the adhesive for the separator 24 and the adhesive for the first insulating film 23 can be selected according to the material of the electrolyte inside the battery cell 20 to reduce the impact of the electrolyte on the stability of the adhesive adhesion. Furthermore, the materials of the adhesive for the separator 24 and the adhesive for the first insulating film 23 can be the same or different; this embodiment is not limited to this.

[0218] In some embodiments, along the length direction of the second end face 2212, the length L1 of the bent portion 2421 is greater than the length L2 of the middle region 22121 of the second end face 2212. As shown in Figures 21 to 23, taking the length direction of the second end face 2212 as the length direction X of the battery cell as an example, the length L1 of each bent portion 2421 can be slightly greater than the length L2 of the middle region 22121 of the second end face 2212 to increase the gap between the separator 24 and the second end face 2212, thereby improving the wetting efficiency.

[0219] In some embodiments, along the width direction of the second end face 2212, the bent portion 2421 covers at least a portion of the edge region 22122 of the second end face 2212 and a portion of the middle region 22121 of the second end face 2212. As shown in Figures 21 to 23, taking the length direction of the second end face 2212 as the length direction X of the battery cell as an example, the bent portion 2421 can cover the area at the junction of the edge region 22122 of the second end face 2212 and the middle region 22121 of the second end face 2212. That is, the edge of the bent portion 2421 facing the middle region 241 of the separator 24 extends beyond the edge of the edge region 22122 of the second end face 2212 facing the middle region 22121 of the second end face 2212, so that more electrolyte can enter the middle region 22121 of the second end face 2212 that is not covered by the first insulating film 23 through the bent portion 2421, thereby improving the wetting efficiency of the electrode assembly assembly 22 and the performance of the battery cell 20.

[0220] It should be understood that the middle region 22121 of the second end face 2212 is the region of the second end face 2212 that is not covered by the first insulating film 23. Correspondingly, the edge region 22122 of the second end face 2212 is the region covered by the first insulating film 23 on the second end face 2212. The edge region 22122 of the second end face 2212 surrounds the middle region 22121 of the second end face 2212.

[0221] According to some embodiments of this application, this application also provides a battery device including a battery cell 20 as described in any of the above embodiments.

[0222] The battery apparatus mentioned in the embodiments of this application may include one or more battery cell assemblies for providing voltage and capacity. A battery cell assembly may include multiple battery cells connected in series, parallel, or mixed connections via a busbar.

[0223] In some embodiments, a battery cell assembly is typically formed by arranging multiple battery cells.

[0224] As an example, a battery cell assembly can be a battery module, which is formed by arranging and fixing multiple battery cells together to form an independent module. As another example, a battery module can be formed by bundling multiple battery cells together with cable ties.

[0225] In some embodiments, the battery device may be a battery pack, which includes a housing and one or more individual battery cells housed within the housing.

[0226] As an example, the battery cell assembly can be a battery module, and the battery cell assembly can be housed in the housing by fixing the battery module in the housing.

[0227] As an example, battery cell assemblies can also be housed in a housing by directly fixing multiple battery cells to the housing.

[0228] As an example, the enclosure may include a first enclosure and a second enclosure. The first enclosure and the second enclosure are fastened together to form a closed space inside the enclosure to house the individual battery cells. Here, "closed" refers to covering or closing, and can be either sealed or unsealed. The first enclosure may be a top cover or a bottom plate.

[0229] As an example, the enclosure may include a top cover, a frame, and a bottom plate. The top cover and bottom plate are connected to the frame, creating an enclosed space inside the enclosure to house the individual battery cells.

[0230] In some embodiments, the housing may be part of the vehicle's chassis structure. For example, a portion of the housing may be at least a part of the vehicle's floor, or a portion of the housing may be at least a part of the vehicle's crossbeams and longitudinal beams.

[0231] According to some embodiments of this application, this application also provides an electrical device including a battery as described in any of the above embodiments, and the battery is used to provide electrical energy to the electrical device.

[0232] Electrical equipment can be any device or system that uses batteries. Examples include mobile phones, portable devices, laptops, electric vehicles, electric toys, power tools, vehicles, ships, and spacecraft, such as airplanes, rockets, space shuttles, and spacecraft.

[0233] This application provides an energy storage device including one or more battery clusters to increase the voltage and capacity of the energy storage device. The battery cluster may include multiple battery devices, which are connected in series via a busbar to increase the voltage of the energy storage device. When the energy storage device includes multiple battery clusters, the multiple battery clusters are connected in parallel to increase the capacity of the energy storage device.

[0234] Energy storage devices can be used in energy storage power stations, wind power generation systems, solar power generation systems, mobile power systems, or temporary power supply systems. Energy storage devices can store electrical energy as needed and output it when appropriate. For example, an energy storage device can store electrical energy during off-peak hours and provide power to relevant users or electrical devices during peak hours. The energy storage system provided in this application embodiment can be any power system that requires energy storage devices.

[0235] In some embodiments, the energy storage device is an energy storage container or an energy storage cabinet.

[0236] In some embodiments, the energy storage device may include a cabinet and one or more battery clusters housed within the cabinet.

[0237] In some embodiments, the energy storage device may include modules such as a thermal management module, a main control module, a central control module, a power distribution module, and a fire protection module.

[0238] As an example, the thermal management module may include a liquid cooling unit that supplies coolant to each battery device via piping to regulate the temperature of the individual battery cells.

[0239] As an example, the main control module can serve as the battery management unit for the battery cluster, used to monitor and manage the battery cluster. The main control module can monitor information such as the current, voltage, power, or temperature of the battery cluster. For instance, it can control the charging and discharging current and voltage of the battery cluster. The main control module includes modules such as an auxiliary battery management unit (SBMU) and a fusion switch.

[0240] As an example, the master control module can serve as the battery management unit for an energy storage device, used to monitor and manage the device. The master control module can monitor information such as the energy storage device's current, voltage, power, state of charge, or temperature. For instance, it can control the charging and discharging current and voltage of the energy storage device. As an example, the master control module may include modules such as an insulation monitoring module (IMM), a master battery management unit (MBMU), an Ethernet (ETH) module, and a fiber optic conversion module.

[0241] As an example, a fire protection system includes control panels, detectors, alarm devices, etc., used to detect, alarm, or extinguish fires in energy storage systems.

[0242] As an example, the power distribution unit can be used to distribute power to the power modules of the energy storage device.

[0243] According to some embodiments of this application, this application also provides an energy storage system, including the energy storage device described in any of the above embodiments. In some embodiments, the energy storage system may include one or more energy storage devices and a power converter system (PCS), the power converter being connected between the power generation device and the energy storage device. The power generation device generates electrical energy, which can be stored in the energy storage device through the power converter. As an example, the power generation device may specifically be a solar panel, a hydroelectric power generation device, a thermal power generation device, a wind power generation device, etc. The specific type of power generation device is not limited in this application.

[0244] According to some embodiments of this application, a charging network is provided. The charging network includes charging piles and an energy storage device. The charging piles are electrically connected to the energy storage device, which provides electrical energy to the charging piles. The charging piles are electrically connected to a battery device in the energy storage device via cables, and the battery device can provide its stored electrical energy to the charging piles. The charging piles have one or more connectors for connecting to electrical devices (such as vehicles), thereby enabling the charging of these devices.

[0245] Energy storage devices can be located inside the charging pile (e.g., an integrated energy storage and charging unit) or outside the charging pile.

[0246] According to some embodiments of this application, referring to Figures 8 to 19, this application provides a battery cell 20, including: a housing 21 having a receiving cavity; electrode terminals 214 disposed on a first wall 201 of the housing 21; and an electrode assembly assembly 22 housed in the receiving cavity, the electrode assembly assembly 22 including at least one electrode assembly 220, the electrode assembly assembly 22 including a main body 221 and tabs 222, the main body 221 including a first end face 2211 and an outer peripheral surface 2213, the outer peripheral surface 2213 intersecting with and surrounding the first end face 2211. The electrode tab 222 is located on the first end face 2211, which faces the first wall 201; the current collector 27 is used to electrically connect the electrode terminal 214 and the electrode tab 222; the first insulating film 23 covers the outer peripheral surface 2213; the second insulating film 26 includes a relatively bent body portion 261 and an extension portion 262. The body portion 261 is disposed between the current collector 27 and the first wall 201 to isolate the current collector 27 and the first wall 201. The extension portion 262 covers a portion of the outer peripheral surface 2213. The first insulating film 23 wraps around and fixes the extension portion 262.

[0247] The second insulating film 26 includes two opposing extensions 262, each covering at least a portion of the two large surfaces 2214 of the outer peripheral surface 2213, wherein the large surface 2214 of the outer peripheral surface 2213 has the largest area. The battery cell also includes an insulating member 25, which is fixed to the first wall 201 and located between the first wall 201 and the first end face 2211. The first insulating film 23 is fixed to the insulating member 25. The body portion 261 is disposed between the current collector 27 and the insulating member 25. The insulating member 25 includes a first electrode lead-out hole 251, through which the electrode terminal 214 is connected to the current collector 27.

[0248] The current collector 27 includes an electrode terminal connection portion 271, and the body portion 261 includes a second electrode lead-out hole 2611. The electrode terminal 214 and / or the electrode terminal connection portion 271 pass through the second electrode lead-out hole 2611 to connect the electrode terminal 214 to the electrode terminal connection portion 271. The current collector 27 also includes a tab connection portion 272 for electrical connection with a tab 222, and the tab connection portion 272 is located between the body portion 261 and the tab 222.

[0249] The battery cell 20 further includes a third insulating film 28, which includes a first region 281 and a second region 282 that are bent relative to each other. The first region 281 is bonded to the tab connection portion 272, and the second region 282 is bonded to and covers a portion of the outer peripheral surface 2213. A second insulating film 26 covers the third insulating film 28. Along the thickness direction of the first wall 201, the length of the extension 262 covering the outer peripheral surface 2213 is greater than the length of the second region 282 covering the outer peripheral surface 2213. The melting point of the third insulating film 28 is greater than the melting point of the second insulating film 26.

[0250] The battery cell also includes a pressure relief mechanism 213, which is disposed on the first wall 201, and the body portion 261 also includes a pressure relief hole 2612 corresponding to the pressure relief mechanism 213. The battery cell also includes an electrolyte injection structure 215, which is disposed on the first wall 201, and the body portion 261 also includes an electrolyte injection hole 2613 corresponding to the electrolyte injection structure 215.

[0251] Along the thickness direction of the first wall 201, the region in which the ratio of the length of the outer peripheral surface 2213 to the length of the outer peripheral surface 2213 is in the range of [0.08, 0.25].

[0252] The electrode assembly 220 has a stacked structure. The first insulating film 23 includes at least one insulating sheet 231, and the first insulating film 23 is folded and adhered to the outer peripheral surface 2213. The first insulating film 23 includes two insulating sheets 231, which respectively cover the two large surfaces 2214 of the outer peripheral surface 2213 and overlap and adhere to the two side surfaces 2215 of the outer peripheral surface 2213 to cover the outer peripheral surface 2213. The area of ​​the side surfaces 2215 of the outer peripheral surface 2213 is smaller than the area of ​​the large surfaces 2214 of the outer peripheral surface 2213.

[0253] The main body 221 also includes a second end face 2212 opposite to the first end face 2211, an outer peripheral surface 2213 connecting the first end face 2211 and the second end face 2212, and a first insulating film 23 covering at least a portion of the second end face 2212. The first insulating film 23 is adhered to and covers the edge region 22122 of the second end face 2212; the battery cell also includes a separator 24, which is adhered to and covers the area of ​​the second end face 2212 not covered by the first insulating film 23, and the separator 24 covers the first insulating film 23.

[0254] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A battery cell, characterized by, include: The outer casing (21) has a receiving cavity; Electrode terminal (214), the electrode terminal (214) is disposed on the first wall (201) of the housing (21); An electrode assembly (22) is housed in the receiving cavity. The electrode assembly (22) includes at least one electrode assembly (220). The electrode assembly (22) includes a main body (221) and a tab (222). The main body (221) includes a first end face (2211) and an outer peripheral face (2213). The outer peripheral face (2213) intersects with and surrounds the first end face (2211). The tab (222) is located on the first end face (2211). The first end face (2211) faces the first wall (201). A current collector (27) is used to electrically connect the electrode terminal (214) and the tab (222); A first insulating film (23) covers the outer peripheral surface (2213); The second insulating film (26) includes a relatively bent body portion (261) and an extension portion (262). The body portion (261) is disposed between the current collecting member (27) and the first wall (201) to isolate the current collecting member (27) and the first wall (201). The extension portion (262) covers a portion of the outer peripheral surface (2213). The first insulating film (23) wraps around and fixes the extension portion (262).

2. The battery cell of claim 1, wherein, The second insulating film (26) includes two oppositely arranged extensions (262), which respectively cover at least a portion of the two large surfaces (2214) of the outer peripheral surface (2213), wherein the large surface (2214) of the outer peripheral surface (2213) is the surface with the largest area of ​​the outer peripheral surface (2213).

3. The battery cell according to claim 1 or 2, characterized in that, The battery cell also includes: An insulating element (25) is fixed to the first wall (201) and located between the first wall (201) and the first end face (2211), and the first insulating film (23) is fixed to the insulating element (25).

4. The battery cell of claim 3, wherein, The main body (261) is disposed between the current collecting member (27) and the insulating member (25).

5. The battery cell according to claim 3 or 4, characterized in that, The insulating component (25) includes a first electrode lead-out hole (251), and the electrode terminal (214) is connected to the current collector (27) through the first electrode lead-out hole (251).

6. The battery cell according to any one of claims 1 to 5, characterized in that, The current collector (27) includes an electrode terminal connection portion (271), and the body portion (261) includes a second electrode lead-out hole (2611). The electrode terminal (214) and / or the electrode terminal connection portion (271) pass through the second electrode lead-out hole (2611) so that the electrode terminal (214) is connected to the electrode terminal connection portion (271).

7. The battery cell according to any one of claims 1 to 6, characterized in that, The current collector (27) includes a tab connection portion (272) for electrical connection with the tab (222), and the tab connection portion (272) is located between the body portion (261) and the tab (222).

8. The battery cell of claim 7, wherein, The battery cell also includes: A third insulating film (28) comprising a first region (281) and a second region (282) that are bent relative to each other, the first region (281) being bonded to the tab connection portion (272), the second region (282) being bonded to and covering a portion of the outer peripheral surface (2213), and the second insulating film (26) covering the third insulating film (28). Along the thickness direction of the first wall (201), the length of the extension (262) covering the outer peripheral surface (2213) is greater than the length of the second region (282) covering the outer peripheral surface (2213).

9. The battery cell of claim 8, wherein, The melting point of the third insulating film (28) is greater than that of the second insulating film (26).

10. The battery cell of any one of claims 1 to 9, wherein, The battery cell also includes: The pressure relief mechanism (213) is disposed on the first wall (201), and the main body (261) further includes a pressure relief hole (2612) corresponding to the pressure relief mechanism (213).

11. The battery cell of any one of claims 1 to 10, wherein, The battery cell also includes: The liquid injection structure (215) is disposed on the first wall (201), and the body part (261) further includes a liquid injection hole (2613) corresponding to the liquid injection structure (215).

12. The battery cell of any one of claims 1 to 11, wherein, Along the thickness direction of the first wall (201), the region in which the length of the extension (262) covers the ratio of the length of the outer peripheral surface (2213) to the length of the outer peripheral surface (2213) is in the range of [0.08, 0.25].

13. The battery cell according to any one of claims 1 to 12, characterized in that, The electrode assembly (220) has a stacked structure.

14. The battery cell of claim 13, wherein, The electrode assembly (220) includes a first surface (2201) and a second surface (2202) disposed opposite to each other along the thickness direction of the electrode assembly (220). The electrode assembly (220) also includes a plurality of fixing structures (2203) disposed at intervals. Each of the plurality of fixing structures (2203) extends from the edge of the first surface (2201) along the thickness direction of the electrode assembly (220) to the edge of the second surface (2202). The second insulating film (26) covers the plurality of fixing structures (2203).

15. The battery cell of any one of claims 1 to 14, wherein, The first insulating film (23) includes at least one insulating sheet (231), and the first insulating film (23) is folded and adhered to the outer peripheral surface (2213).

16. The battery cell according to claim 15, characterized in that, The first insulating film (23) includes two insulating sheets (231), which respectively cover the two large surfaces (2214) of the outer peripheral surface (2213) and overlap and adhere to the two side surfaces (2215) of the outer peripheral surface (2213) to cover the outer peripheral surface (2213). The area of ​​the side surfaces (2215) of the outer peripheral surface (2213) is smaller than the area of ​​the large surfaces (2214) of the outer peripheral surface (2213).

17. The battery cell according to claim 16, characterized in that, The electrode assembly (22) includes a first electrode assembly (2201) and a second electrode assembly (2202), with an insulating sheet (231) attached to the side of the outer peripheral surface of the first electrode assembly (2201) and attached to the side of the outer peripheral surface of the second electrode assembly (2202).

18. The battery cell according to any one of claims 1 to 17, characterized in that, The main body (221) also includes a second end face (2212) opposite to the first end face (2211), the outer peripheral surface (2213) connects the first end face (2211) and the second end face (2212), and the first insulating film (23) covers at least a portion of the second end face (2212).

19. The battery cell according to claim 18, characterized in that, The first insulating film (23) is pasted and covers the edge region (22122) of the second end face (2212); The battery cell also includes: A separator (24) is attached to and covers the area of ​​the second end face (2212) that is not covered by the first insulating film (23), and the separator (24) covers the first insulating film (23).

20. The battery cell according to any one of claims 1 to 19, characterized in that, The outer casing (21) includes: The housing (211) has an opening (2111); A cover plate (212) for covering the opening (2111) to form the receiving cavity, the cover plate (212) including the first wall (201).

21. A battery device, characterized in that, include: Multiple battery cells according to any one of claims 1 to 20.

22. An energy storage device, characterized in that, include: A plurality of battery cells according to any one of claims 1 to 20 or a plurality of battery devices according to claim 21, wherein the battery cells or the battery devices are used to store or provide electrical energy.

23. An energy storage system, characterized in that, include: Power conversion device; The energy storage device as claimed in claim 22, wherein the power conversion device is used to electrically connect the power generation device and the energy storage device.

24. A charging network, characterized in that, include: Charging stations; The energy storage device as described in claim 22 or the energy storage system as described in claim 23, wherein the energy storage device is used to provide electrical energy to the charging pile.

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