Battery cell, method for manufacturing battery cell, battery device and power-using device

Abstract

The present application provides a battery cell, a method for manufacturing a battery cell, a battery device and an electrical device. The battery cell includes a shell and an insulating film, the outer surface of the shell includes two first surfaces, a second surface and a third surface, and the first surface, the second surface and the third surface intersect with each other. The insulating film is integrally arranged and includes a main body area and a tail area, the main body area covers the two first surfaces and the second surface, and the tail area covers the third surface and connects to the main body area. Among them, the tail area includes a first folded ear and a second folded ear, a part of the first folded ear is self-folded to form a folded portion with multiple layers of insulating film, the folded portion is stacked on the side of the second folded ear facing away from the third surface, and at least part of the folded edge of the folded portion is exposed on the side surface of the second folded ear facing away from the third surface, and the second folded ear is at least fused with the folded edge exposed on the side surface of the second folded ear facing away from the third surface. According to the present application, the reliability and energy density of the battery cell can be effectively improved.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a battery cell, a method for manufacturing a battery cell, a battery device, and an electrical device. Background Art

[0002] With the development of new energy technology, batteries are used more and more widely, for example, in mobile phones, laptops, electric vehicles, electric cars, electric airplanes, electric ships, electric toy cars, electric toy ships, electric toy airplanes and electric tools, etc.

[0003] The outer surface of the battery cell shell is usually covered with an insulating film to protect the battery cell. However, the current insulating film usually forms a multi-layer folded structure in part of the battery cell shell, which not only affects the reliability of the battery cell, but also increases the outer size of the battery cell and reduces the energy density of the battery cell. Therefore, how to effectively improve the reliability and energy density of the battery cell is a technical problem that needs to be solved in battery technology. Summary of the invention

[0004] In view of the above problems, the present application provides a battery cell, a method for manufacturing a battery cell, a battery device and an electrical device, which can effectively improve the reliability and energy density of the battery cell.

[0005] In a first aspect, an embodiment of the present application provides a battery cell, the battery cell includes a shell and an insulating film, the outer surface of the shell includes two first surfaces, a second surface and a third surface, the two first surfaces are arranged oppositely, the second surface connects the two first surfaces, the third surface connects the two first surfaces, and the first surface, the second surface and the third surface intersect with each other. The insulating film is arranged in one piece and includes a main body area and a tail area, the main body area covers the two first surfaces and the second surface, and the tail area covers the third surface and connects the main body area. Wherein, the tail area includes a plurality of folded ears, the plurality of folded ears at least partially overlap, the plurality of folded ears include a first folded ear and a second folded ear, a portion of the first folded ear is self-folded to form a folded portion with multiple layers of insulating film, the folded portion is stacked on the side of the second folded ear facing away from the third surface, and at least a portion of the folded edge of the folded portion is exposed on the side surface of the second folded ear facing away from the third surface, and the second folded ear is at least fused with the folded edge exposed on the side surface of the second folded ear facing away from the third surface. Wherein, there is an indentation on the tail area, and the indentation at least covers the folded edge exposed on the side surface of the first folded ear facing away from the third surface.

[0006] The above technical solution can cut off the conductive relationship between the gap between the folded portion and the second folded ear and the external environment, or eliminate the gap between the folded portion and the second folded ear, by welding the second folded ear at least to the folded edge exposed on the side surface of the second folded ear facing away from the third surface, thereby not only reducing the risk of insulation failure when abnormalities such as electrolyte leakage or thermal runaway occur in the battery cell to improve the reliability of the battery cell, but also reducing the overall thickness of the insulating film to improve the energy density of the battery cell. In addition, on the one hand, it can enable operators or identification devices to quickly and accurately determine whether the folded portion and the second folded ear have been welded, thereby improving the overall production efficiency of the battery cell; on the other hand, it can utilize the existing hot pressing equipment in the battery production system, which can help reduce costs.

[0007] In some embodiments of the first aspect, the entire folded portion is welded to the second flap.

[0008] The gap between the folded portion and the second folded ear can be eliminated, so that the reliability of the battery cell can be further improved, and the energy density of the battery cell can be further improved.

[0009] In some embodiments of the first aspect, the indentation covers the fold.

[0010] By increasing the hot pressing area, the risk of incomplete welding of the fold edge exposed on the side of the first fold ear facing away from the third surface and the second fold ear due to pressure leakage can be reduced, thereby further improving the reliability of welding.

[0011] In some embodiments of the first aspect, there are multiple folding portions, and there are multiple indentations, and the number of indentations is not less than the number of folding portions, and each indentation at least partially overlaps with the folding portion.

[0012] By performing multiple heat pressing operations on the insulating film in sequence, key areas can be welded more specifically, and the heat pressing area can be reduced while meeting the welding requirements, thereby helping to reduce costs.

[0013] In some embodiments of the first aspect, the outer surface of the housing includes two third surfaces, the two third surfaces are arranged opposite to each other, and the second surface connects the two first surfaces and the two third surfaces. The main body area includes two first sub-areas and a second sub-area, the two first sub-areas are respectively covered on the two first surfaces, and the second sub-area is covered on the second surface, and the insulating film includes two tail areas, and the two tail areas are respectively covered on the two third surfaces. Each tail area includes two first folding ears and a second folding ear, the first folding ear is connected to an end of the first sub-area close to the third surface, and the two first folding ears located in the same tail area are respectively folded from the two first sub-areas toward the third surface, and the second folding ear is connected to an end of the second sub-area close to the third surface and folded from the second sub-area toward the third surface.

[0014] The coating method of the above technical solution is conducive to reducing the area of ​​the folded portion in the tail area, thereby reducing the welding difficulty and welding area between the folded portion and the second folded ear, so as to improve the welding efficiency and reduce the cost.

[0015] In some embodiments of the first aspect, two first folded ears located in the same tail region partially overlap.

[0016] The above technical solution can reduce the risk of partial exposure of the outer surface of the shell to the external environment due to incomplete coverage of the tail area by overlapping the two first folded ears located in the same tail area, thereby improving the coverage effect of the insulating film and thus improving the reliability of the battery cell.

[0017] In some embodiments of the first aspect, overlapping portions of two first folded ears located in the same finishing area are welded.

[0018] The above technical solution can reduce the thickness of the overlapping portion of the two first folded ears by welding the overlapping portions of the two first folded ears located in the same tailing area, thereby facilitating reducing the overall volume of the battery cell to improve the energy density of the battery cell.

[0019] In some embodiments of the first aspect, the battery cell further includes a connector, which at least connects the fold edge exposed on the side of the second fold ear facing away from the third surface and the second fold ear, and the melting point of the connector is lower than the melting point of the insulating film.

[0020] In this way, the above technical solution can effectively reduce the temperature during the welding process and reduce the risk of high-temperature damage to the insulating film by additionally providing a low-melting-point connecting piece while achieving welding between the folded portion and the second folded ear.

[0021] In some embodiments of the first aspect, a portion of the connecting element covers the folded portion.

[0022] By increasing the coverage area of ​​the connector, the risk of incomplete welding of the fold edge exposed on the side of the first fold ear facing away from the third surface with the second fold ear due to incomplete coverage of the connector can be reduced, thereby further improving the reliability of welding.

[0023] In a second aspect, an embodiment of the present application provides a method for manufacturing a battery cell, the method for manufacturing a battery cell comprising:

[0024] A housing is provided, wherein an outer surface of the housing includes two first surfaces, a second surface and a third surface, the two first surfaces are arranged opposite to each other, the second surface connects the two first surfaces, the third surface connects the two first surfaces, and the first surface, the second surface and the third surface intersect with each other;

[0025] An insulating film is provided, and the insulating film is coated on the outer surface of the housing, wherein the insulating film is integrally provided and includes a main body area and a tail area, the main body area covers the first surface and the second surface, the tail area covers the third surface and is connected to the main body area, the tail area includes a plurality of folded ears, the plurality of folded ears at least partially overlap, the plurality of folded ears include a first folded ear and a second folded ear, a portion of the first folded ear is self-folded to form a folded portion having a plurality of insulating films, the folded portion is stacked on a side of the second folded ear facing away from the third surface, and at least a portion of a folded edge of the folded portion is exposed on a surface of a side of the second folded ear facing away from the third surface;

[0026] The insulating film is processed so that the second folded ear is at least fused to the fold edge exposed on the side of the second folded ear facing away from the third surface;

[0027] The processing of the insulating film includes: hot pressing the insulating film to form an indentation.

[0028] The above technical solution can cut off the conductive relationship between the gap between the folded portion and the second folded ear and the external environment, or eliminate the gap between the folded portion and the second folded ear, by welding the second folded ear at least to the fold edge exposed on the side surface of the second folded ear facing away from the third surface. This can not only reduce the risk of insulation failure when abnormalities such as electrolyte leakage or thermal runaway occur in the battery cell to improve the reliability of the battery cell, but also reduce the overall thickness of the insulating film to improve the energy density of the battery cell.

[0029] In addition, on the one hand, it can enable the operator or identification device to quickly and accurately determine whether the folding part and the second folding ear have been welded, thereby improving the overall production efficiency of the battery cell; on the other hand, it can utilize the existing hot pressing equipment in the battery production system, which can help reduce costs.

[0030] In some embodiments of the second aspect, performing heat pressing on the insulating film to form the indentations includes performing heat pressing on the insulating film multiple times to form multiple indentations.

[0031] By performing multiple hot pressing operations on the insulating film in sequence, the key areas can be welded more specifically, which can reduce the hot pressing area while meeting the welding requirements, thereby helping to reduce costs.

[0032] In some embodiments of the second aspect, the duration of heat pressing does not exceed 5 seconds.

[0033] The risk of damage to the insulating film during the hot pressing process can be effectively reduced.

[0034] In some embodiments of the second aspect, processing the insulating film includes:

[0035] Providing a connecting member, at least a portion of which is disposed between the second folded ear and a fold edge exposed on a side surface of the second folded ear facing away from the third surface, wherein the melting point of the connecting member is lower than the melting point of the insulating film;

[0036] The connecting member is heated to melt the connecting member and connect at least the second folded ear and the fold edge exposed on the side surface of the second folded ear facing away from the third surface.

[0037] The above technical solution can effectively reduce the temperature during the welding process and reduce the risk of high-temperature damage to the insulating film by additionally providing a low-melting-point connecting piece while achieving welding between the folded portion and the second folded ear.

[0038] In a third aspect, the present application provides a battery device, which includes a battery cell provided by any embodiment of the first aspect.

[0039] In a fourth aspect, the present application provides an electrical device, comprising a battery cell provided by any embodiment of the first aspect, wherein the battery cell is used to provide electrical energy.

[0040] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present application. Also, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

[0042] Figure 1 A schematic diagram of the structure of a vehicle provided in some embodiments of the present application;

[0043] Figure 2 A schematic diagram of an exploded structure of a battery device provided in some embodiments of the present application;

[0044] Figure 3 A schematic diagram of the structure of a battery module provided in some embodiments of the present application;

[0045] Figure 4 A schematic diagram of a three-dimensional structure of a battery cell provided in some embodiments of the present application;

[0046] Figure 5 A three-dimensional structural schematic diagram of the positional relationship between a battery cell and an insulating film provided in some embodiments of the present application;

[0047] Figure 6 A schematic diagram of a three-dimensional structure in which a first surface of a battery cell and a main body area of ​​an insulating film are attached, and a second surface of the battery cell and a main body area of ​​the insulating film are attached, provided in some embodiments of the present application;

[0048] Figure 7 A schematic diagram of a three-dimensional structure in which a third surface of a battery cell and a second folded ear of an insulating film are attached to each other in some embodiments of the present application;

[0049] Figure 8 A schematic diagram of a three-dimensional structure in which a third surface of a battery cell and a first folded ear of an insulating film are attached to each other in some embodiments of the present application;

[0050] Fig. 9 A schematic diagram of a side view structure of a battery cell provided in some embodiments of the present application;

[0051] Fig.10 A schematic side view of another battery cell provided in some embodiments of the present application;

[0052] Fig.11 A schematic diagram of a side view structure of another battery cell provided in some embodiments of the present application;

[0053] Fig.12 A schematic diagram of a side view structure of another battery cell provided in some embodiments of the present application;

[0054] Fig.13 A schematic side view of a battery cell provided in some embodiments of the present application;

[0055] Fig.14 A process flow chart of a method for manufacturing a battery cell provided in some embodiments of the present application.

[0056] The reference numerals in the specific implementation manner are as follows:

[0057] 1. Vehicle; 2. Battery device; 3. Controller; 4. Motor; 5. Box; 5a. First box portion; 5b. Second box portion; 5c. Accommodation space; 6. Battery module; 7. Battery cell;

[0058] 10. Shell; 11. First surface; 12. Second surface; 13. Third surface; 20. Insulating film; 21. Main body area; 22. Finishing area; 221. First fold ear; 2211. Folding part; 2212. Crease edge; 2213. Connecting part; 222. Second fold ear; 30. Indentation; 40. Connecting piece. DETAILED DESCRIPTION

[0059] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0060] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as those commonly understood by technicians in the technical field to which this application belongs; the terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned drawings are intended to cover non-exclusive inclusions. The terms "first", "second", etc. in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order or a primary and secondary relationship.

[0061] Reference to "embodiment" in this application means that a particular feature, structure, or characteristic described in conjunction with the embodiment may be included in at least one embodiment of the present application. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments.

[0062] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", and "attached" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0063] The term "and / or" in this application is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this application generally indicates that the associated objects before and after are in an "or" relationship.

[0064] In the embodiments of the present application, the same reference numerals represent 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 the present application shown in the drawings, as well as the overall thickness, length, width and other dimensions of the integrated device are only exemplary descriptions and should not constitute any limitation to the present application.

[0065] The term “plurality” used in this application refers to two or more (including two).

[0066] In the present application, the term "parallel" includes not only the absolutely parallel situation, but also the roughly parallel situation conventionally recognized in engineering; meanwhile, "vertical" includes not only the absolutely vertical situation, but also the roughly vertical situation conventionally recognized in engineering.

[0067] In the embodiment of the present application, the battery cell may be a secondary battery cell, which refers to a battery cell that can be continuously used by activating active materials by charging after the battery cell is discharged.

[0068] The battery cells can be lithium-ion battery cells, sodium-ion battery cells, sodium-lithium-ion battery cells, lithium metal battery cells, sodium metal battery cells, lithium-sulfur battery cells, magnesium-ion battery cells, nickel-hydrogen battery cells, nickel-cadmium battery cells, lead-acid battery cells, etc., which are not limited in the embodiments of the present application.

[0069] In some embodiments, the battery cell may include a housing. The housing is used to encapsulate components such as electrode assemblies and electrolytes. The housing may be a steel housing, an aluminum housing, a plastic housing (such as polypropylene), a composite metal housing (such as a copper-aluminum composite housing), or an aluminum-plastic film.

[0070] As an example, the battery cell may be a cylindrical battery cell, a prismatic battery cell, a soft-pack battery cell or a battery cell of other shapes. The prismatic battery cell includes a square-shell battery cell, a blade-shaped battery cell, a polygonal battery, such as a hexagonal battery.

[0071] The battery device mentioned in the embodiments of the present application may include one or more battery cell assemblies for providing voltage and capacity. The battery cell assembly may include a plurality of battery cells, and the plurality of battery cells are connected in series, in parallel or in mixed connection through a busbar.

[0072] In some embodiments, the battery cell assembly is generally formed by arranging a plurality of battery cells; as an example, the battery cell assembly may be a battery module, which is formed by arranging and fixing a plurality of battery cells to form an independent module. As an example, the battery module may be formed by bundling a plurality of battery cells by a cable tie.

[0073] In some embodiments, the battery device may be a battery pack, which includes a case and one or more battery cell assemblies, wherein the battery cell assemblies are accommodated in the case.

[0074] As an example, the battery cell assembly may be a battery module, and the battery cell assembly may be accommodated in the box by fixing the battery module in the box.

[0075] As an example, the battery cell assembly may also be housed in the case by directly fixing a plurality of battery cells to the case.

[0076] In some embodiments, the box body can be used as a part of the chassis structure of the vehicle. For example, part of the box body can become at least a part of the floor of the vehicle, or part of the box body can become at least a part of the cross beam and longitudinal beam of the vehicle.

[0077] In some embodiments, the battery device may be an energy storage device, which includes an energy storage container, an energy storage cabinet, and the like.

[0078] With the development of new energy technology, batteries are used more and more widely, for example, in mobile phones, laptops, electric vehicles, electric cars, electric airplanes, electric ships, electric toy cars, electric toy ships, electric toy airplanes and electric tools, etc.

[0079] The battery device generally includes a housing and a plurality of battery cells. The outer surfaces of the housings of the battery cells are generally coated with an insulating film to protect the battery cells.

[0080] In current battery cells, the insulating film coating of the battery cell is usually carried out by using a round-shaped coating or a U-shaped coating, which is simple, convenient and fast. However, the above coating method usually forms a folded multi-layer insulating film in part of the outer shell, and the insulating film is usually provided with adhesive on one side. In the folded multi-layer insulating film, there is a folded portion formed by the self-folding of part of the insulating film, so that there is no adhesive on both sides of the folded portion along its own thickness direction. Therefore, on the one hand, in the folded multi-layer insulating film, a gap will be generated between the folded portion and the insulating film adjacent to it. When the battery cell has abnormalities such as electrolyte leakage or thermal runaway, the gap between the folded portion and the insulating film adjacent to it will produce a capillary effect, and the electrolyte will enter the gap and conduct the outer shell and the box under the action of voltage, causing insulation failure, thereby affecting the reliability of the battery cell. On the other hand, it will cause the outer dimensions of the battery cell to increase and reduce the energy density of the battery cell.

[0081] Based on the above considerations, an embodiment of the present application provides a battery cell, the battery cell includes a shell and an insulating film, the outer surface of the shell includes two first surfaces, a second surface and a third surface, the two first surfaces are arranged opposite to each other, the second surface connects the two first surfaces, the third surface connects the two first surfaces, and the first surface, the second surface and the third surface intersect with each other. The insulating film is arranged in one piece and includes a main body area and a tail area, the main body area covers the two first surfaces and the second surface, and the tail area covers the third surface and connects the main body area. Among them, the tail area includes a plurality of folded ears, the plurality of folded ears at least partially overlap, the plurality of folded ears include a first folded ear and a second folded ear, a portion of the first folded ear is self-folded to form a folded portion with multiple layers of insulating film, the folded portion is stacked on the side of the second folded ear facing away from the third surface, and at least a portion of the folded edge of the folded portion is exposed on the side surface of the second folded ear facing away from the third surface, and the second folded ear is at least fused to the folded edge exposed on the side surface of the second folded ear facing away from the third surface.

[0082] A portion of the first folded ear is self-folded to form a folded portion with a multi-layer insulation film, and there is no adhesive on both sides of the folded portion along its own thickness direction, so a gap is generated between the folded portion and the second folded ear. In this way, the above technical solution can cut off the conductive relationship between the gap between the folded portion and the second folded ear and the external environment by welding the second folded ear at least to the fold edge exposed on the side surface of the second folded ear facing away from the third surface, or eliminate the gap between the folded portion and the second folded ear, thereby not only reducing the risk of insulation failure when abnormalities such as electrolyte leakage or thermal runaway occur in the battery cell, thereby improving the reliability of the battery cell, but also reducing the overall thickness of the insulation film, thereby improving the energy density of the battery cell.

[0083] The technical solutions described in the embodiments of the present application are applicable to battery devices and electrical devices using the battery devices.

[0084] The electrical device may be a vehicle, a mobile phone, a portable device, a laptop computer, a ship, a spacecraft, an electric toy, an electric tool, and the like. The vehicle may be a fuel vehicle, a gas vehicle, or a new energy vehicle, and the new energy vehicle may be a pure electric vehicle, a hybrid vehicle, or an extended-range vehicle, and the like; the spacecraft may include an airplane, a rocket, a space shuttle, and a spacecraft, and the like; the electric toy may include a fixed or mobile electric toy, such as a game console, an electric car toy, an electric ship toy, and an electric airplane toy, and the like; the electric tool may include a metal cutting electric tool, a grinding electric tool, an assembly electric tool, and an electric tool for railways, such as an electric drill, an electric grinder, an electric wrench, an electric screwdriver, an electric hammer, an impact drill, a concrete vibrator, and an electric planer, and the like. The embodiments of the present application do not impose any special restrictions on the above-mentioned electrical devices.

[0085] It should be understood that the technical solutions described in the embodiments of the present application are not limited to the battery devices and electrical devices described above, but can also be applied to all battery devices including a box and electrical devices using the battery devices. However, for the sake of simplicity, the following embodiments are described using electric vehicles as examples.

[0086] Figure 1 A schematic diagram of the structure of a vehicle provided for some embodiments of the present application.

[0087] Continue to refer Figure 1 The vehicle 1 is provided with a battery device 2 inside, and the battery device 2 can be provided at the bottom, head, or tail of the vehicle 1. The battery device 2 can be used for powering the vehicle 1, for example, the battery device 2 can be used as an operating power source for the vehicle 1.

[0088] The vehicle 1 may further include a controller 3 and a motor 4 , wherein the controller 3 is used to control the battery device 2 to supply power to the motor 4 , for example, to meet the power requirements of starting, navigating and driving the vehicle 1 .

[0089] In some embodiments of the present application, the battery device 2 can not only serve as an operating power source for the vehicle 1, but also serve as a driving power source for the vehicle 1, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1.

[0090] Figure 2 A schematic diagram of an exploded structure of a battery device provided in some embodiments of the present application.

[0091] Continue to refer Figure 2 The battery device 2 includes a box body 5 and a battery cell, and the battery cell is accommodated in the box body 5.

[0092] The box 5 is used to accommodate the battery cells, and the box 5 can be of various structures. In some embodiments, the box 5 can include a first box portion 5a and a second box portion 5b, the first box portion 5a and the second box portion 5b cover each other, and the first box portion 5a and the second box portion 5b jointly define a storage space 5c for accommodating the battery cells. The second box portion 5b can be a hollow structure with one end open, the first box portion 5a is a plate-like structure, and the first box portion 5a covers the open side of the second box portion 5b to form a box 5 with a storage space 5c; the first box portion 5a and the second box portion 5b can also be hollow structures with one side open, and the open side of the first box portion 5a covers the open side of the second box portion 5b to form a box 5 with a storage space 5c. Of course, the first box portion 5a and the second box portion 5b can be of various shapes, such as a cylinder, a cuboid, etc.

[0093] In order to improve the sealing performance after the first box body part 5a and the second box body part 5b are connected, a sealing member, such as a sealant, a sealing ring, etc., may also be provided between the first box body part 5a and the second box body part 5b.

[0094] Assuming that the first box body portion 5a covers the top of the second box body portion 5b, the first box body portion 5a can also be called an upper box cover, and the second box body portion 5b can also be called a lower box.

[0095] In the battery device 2, there can be one or more battery cells. If there are more than one battery cell, the battery cells can be connected in series, in parallel or in a mixed connection. A mixed connection means that the battery cells are connected in series and in parallel. The battery cells can be directly connected in series, in parallel or in a mixed connection, and then the whole formed by the battery cells can be accommodated in the box 5; of course, the battery modules 6 can also be formed by connecting the battery cells in series, in parallel or in a mixed connection, and then the battery modules 6 can be connected in series, in parallel or in a mixed connection to form a whole and accommodated in the box 5.

[0096] Figure 3 A schematic structural diagram of a battery module provided in some embodiments of the present application.

[0097] In some embodiments, referring to the figure, there are multiple battery cells 7, and the multiple battery cells 7 are first connected in series, parallel or mixed to form a battery module 6. The multiple battery modules 6 are then connected in series, parallel or mixed to form a whole, and are accommodated in the box.

[0098] The multiple battery cells 7 in the battery module 6 can be electrically connected through a busbar component to achieve parallel connection, series connection or mixed connection of the multiple battery cells 7 in the battery module 6 .

[0099] Figure 4 A schematic diagram of a three-dimensional structure of a battery cell provided in some embodiments of the present application. Figure 5 A three-dimensional structural schematic diagram of the positional relationship between a battery cell and an insulating film provided in some embodiments of the present application, Figure 6 A schematic diagram of a three-dimensional structure in which a first surface of a battery cell and a main body area of ​​an insulating film are attached, and a second surface of the battery cell and a main body area of ​​the insulating film are attached, provided in some embodiments of the present application. Figure 7 This is a schematic diagram of a three-dimensional structure in which a third surface of a battery cell and a second folded ear of an insulating film are attached to each other in some embodiments of the present application. Figure 8 This is a schematic diagram of a three-dimensional structure in which a third surface of a battery cell and a first folded ear of an insulating film are attached to each other in some embodiments of the present application. Fig. 9 A schematic side view of the structure of a battery cell provided in some embodiments of the present application.

[0100] refer to Figures 4 to 9The embodiment of the present application provides a battery cell 7, the battery cell 7 includes a shell 10 and an insulating film 20, the outer surface of the shell 10 includes two first surfaces 11, a second surface 12 and a third surface 13, the two first surfaces 11 are arranged opposite to each other, the second surface 12 connects the two first surfaces 11, the third surface 13 connects the two first surfaces 11, and the first surface 11, the second surface 12 and the third surface 13 intersect each other. The insulating film 20 is integrally arranged and includes a main body area 21 and a tail area 22, the main body area 21 covers the two first surfaces 11 and the second surface 12, and the tail area 22 covers the third surface 13 and connects the main body area 21. Among them, the tail area 22 includes a plurality of folded ears, and the plurality of folded ears at least partially overlap, and the plurality of folded ears include a first folded ear 221 and a second folded ear 222. A portion of the first folded ear 221 is self-folded to form a folding portion 2211 having a multi-layer insulating film 20, and the folding portion 2211 is stacked on the side of the second folded ear 222 facing away from the third surface 13, and at least a portion of the folding edge 2212 of the folding portion 2211 is exposed on the side surface of the second folded ear 222 facing away from the third surface 13, and the second folded ear 222 is at least welded to the folding edge 2212 exposed on the side surface of the second folded ear 222 facing away from the third surface 13.

[0101] Exemplarily, the housing 10 is a component for forming the internal environment of the battery cell 7. The formed internal environment can be used to accommodate electrode assemblies, electrolytes and other components. The electrode assembly is a component in the battery cell 7 where electrochemical reactions occur. The electrode assembly is mainly formed by winding or stacking positive and negative electrode sheets, and a separator is usually provided between the positive and negative electrode sheets. The parts of the positive and negative electrode sheets with active materials constitute the main body of the electrode assembly, and the parts of the positive and negative electrode sheets without active materials each constitute a lug. The positive electrode lug and the negative electrode lug can be located together at one end of the main body or respectively at both ends of the main body. During the charge and discharge process of the battery cell 7, the positive electrode active material and the negative electrode active material react with the electrolyte, and the lugs connect the electrode terminals to form a current loop.

[0102] Optionally, the housing 10 may be but is not limited to being made of metal or non-metal materials. For example, the metal material may be copper, aluminum or stainless steel, etc.; the non-metal material may be polyethylene, polypropylene or polyvinyl chloride, etc.

[0103] In some embodiments of the present application, the housing 10 is square, and the housing 10 includes a shell and an end cover, the shell has an opening, and the end cover covers the opening. The first surface 11, the second surface 12, and the third surface 13 are all arranged on the shell. The first surface 11 can be understood as a large surface on the circumferential side of the shell, wherein the circumferential side refers to the surface along the opening, and the large surface means the surface with a larger area on the circumferential side of the shell. One of the second surface 12 and the third surface 13 can be understood as a small surface on the circumferential side of the shell, and the other of the second surface 12 and the third surface 13 can be understood as the bottom surface of the shell, wherein the small surface means the surface with a smaller area on the circumferential side of the shell, and the bottom surface refers to the surface on the shell opposite to the opening.

[0104] In some examples, when the square housing 10 is coated with the insulating film 20 in a round-shaped coating manner, the first surface 11 is a large surface, the second surface 12 is a small surface, and the third surface 13 is a bottom surface.

[0105] In some examples, when the square housing 10 is coated with the insulating film 20 in a U-shaped coating manner, the first surface 11 is a large surface, the second surface 12 is a bottom surface, and the third surface 13 is a small surface.

[0106] In the embodiment disclosed in the present application, an insulating film 20 is coated on the outer surface of the housing 10. The insulating film 20 can provide insulation protection for the battery cell 7, reduce the risk of short circuit of the battery cell 7 during normal use, and make the appearance of the battery cell 7 more beautiful. Optionally, the insulating film 20 can be made of, but not limited to, polyethylene, polypropylene or other high molecular polymer materials.

[0107] The insulating film 20 is integrally provided, which means that the insulating film 20 is already integrally provided before covering the housing 10 .

[0108] The main area 21 refers to the portion of the insulating film 20 that covers the outer shell 10 in a flat manner, and the tail area 22 refers to the portion of the insulating film 20 that covers the outer shell 10 in a folded manner. In other words, in the process of coating the battery cell 7 with the insulating film 20, the insulating film 20 first covers the first surface 11 and the second surface 12 of the outer shell 10 to form the main area 21, and the portion of the insulating film 20 that exceeds the main area 21 is used as a plurality of folded ears, and the plurality of folded ears are then covered on the third surface 13 of the outer shell 10 in a folded form to form the tail area 22. It should be noted that the coverage area of ​​the main area 21 is usually larger than the coverage area of ​​the tail area 22.

[0109] It can be understood that, in the process of covering the third surface 13 of the shell 10 by folding to form the end area 22, the folding of each folding ear in the plurality of folding ears has a sequence.

[0110] The second folded ear 222 refers to the folded ear that is folded first, and the second folded ear 222 will be attached to the third surface 13 in a flat form. The first folded ear 221 refers to the folded ear that is folded later relative to the second folded ear 222. Since the insulating film 20 is integrally arranged, the first folded ear 221 and the second folded ear 222 are connected. During the folding process of the second folded ear 222, a part of the first folded ear 221 close to the second folded ear 222 will be driven to be folded synchronously, so that the part of the first folded ear 221 close to the second folded ear 222 is folded with another part of the first folded ear 221 to form a folded portion 2211 with two layers of insulating film 20. After the first folded ear 221 is folded, the folded portion 2211 will be stacked on the side of the second folded ear 222 facing away from the third surface 13.

[0111] It should be noted that, in the process of folding the second folded ear 222, the first folded ear 221 is affected by the folding of the second folded ear 222 to form the folded portion 2211. Depending on the specific folding method, the folded portion 2211 with two layers of insulating film 20, three layers of insulating film 20, or more layers of insulating film 20 can be formed. In other words, the formation of the folded portion 2211 can be described as a folded structure with multiple layers of insulating film 20 formed by self-folding of a part of the first folded ear 221. In order to more clearly illustrate the embodiments of the present application, the following is an example of the folding of the part of the first folded ear 221 close to the second folded ear 222 and the other part of the first folded ear 221 to form the folded portion 2211 with two layers of insulating film 20.

[0112] In the embodiment disclosed in the present application, the insulating film 20 is usually provided with adhesive on one side, that is, the insulating film 20 has one adhesive backing surface. In the process of coating the battery cell 7 with the insulating film 20, the insulating film 20 is first attached to the first surface 11 and the second surface 12 of the housing 10 through the adhesive backing surface to form a main body area 21, and the portion of the insulating film 20 that exceeds the main body area 21 is used as a plurality of folded ears, and the plurality of folded ears are folded and attached to the third surface 13 of the housing 10 through the adhesive backing surface to form a tail area 22.

[0113] In the folding portion 2211, the portion of the first folding ear 221 close to the second folding ear 222 is folded in half with the other portion of the first folding ear 221, that is, the adhesive surface of the portion of the first folding ear 221 close to the second folding ear 222 is attached to the adhesive surface of the other portion of the first folding ear 221, so that there is no adhesive on both sides of the folding portion 2211 along its thickness direction. Therefore, a gap will be generated between the folding portion 2211 and the second folding ear 222. When the battery cell 7 has abnormalities such as electrolyte leakage or thermal runaway, the gap between the folding portion 2211 and the second folding ear 222 will produce a capillary effect, and the electrolyte will enter the gap and conduct the shell 10 and the box body under the action of voltage, causing insulation failure, thereby affecting the reliability of the battery cell 7.

[0114] The specific structures of the embodiments of the present application are introduced below using the round-shaped encapsulation method and the U-shaped encapsulation method. It should be noted that: Figures 5 to 8 This is a schematic diagram of the specific step structure of the U-shaped encapsulation method. The specific step structure schematic diagram of the round-shaped encapsulation method can refer to the existing relevant step diagrams and will not be illustrated here.

[0115] In some examples, when the square shell 10 is coated with the insulating film 20 in a U-shaped coating method, the shell 10 includes two first surfaces 11, one second surface 12 and two third surfaces 13, the first surface 11 is the large surface among the circumferential side surfaces of the square shell 10, the second surface 12 is the bottom surface of the square shell 10, and the third surface 13 is the small surface among the circumferential side surfaces of the square shell 10.

[0116] The insulating film 20 has two tail regions 22 and six folded ears, wherein each tail region 22 is formed by three folded ears. Specifically, the insulating film 20 will first cover the two first surfaces 11 and one second surface 12 of the housing 10 to form a main body region 21 and six folded ears. For ease of description, the two third surfaces 13 are respectively configured as the first facet and the second facet, and the two tail regions 22 are respectively configured as the first tail region and the second tail region. Three of the six folded ears are connected to one end of the main body region 21 close to the first facet and surround the periphery of the first facet, and these three folded ears are folded toward the first facet to cover the first facet to form a first tail region; and the other three of the six folded ears are connected to one end of the main body region 21 close to the second facet and surround the periphery of the second facet, and these three folded ears are folded toward the second facet to cover the second facet to form a second tail region.

[0117] In the first tailing area, two of the three folded ears in the first tailing area are configured as two first folded ears 221, and another of the three folded ears in the first tailing area is configured as a second folded ear 222. The two first folded ears 221 are respectively connected to one end of the main area 21 covering the two first surfaces 11 close to the first small face, and the second folded ear 222 is connected to one end of the main area 21 covering the second surface 12 close to the first small face. Each first folded ear 221 has a folded portion 2211.

[0118] In the second tailing area, two of the three folded ears in the second tailing area are configured as two first folded ears 221, and another of the three folded ears in the second tailing area is configured as a second folded ear 222. The two first folded ears 221 are respectively connected to one end of the main body area 21 covering the two first surfaces 11 close to the first small face, and the second folded ear 222 is connected to one end of the main body area 21 covering the second surface 12 close to the first small face. Each first folded ear 221 has a folded portion 2211.

[0119] In some examples, when the square shell 10 is wrapped with an insulating film 20 in a zigzag wrapping manner, the shell 10 includes two first surfaces 11, two second surfaces 12 and one third surface 13, the first surface 11 is a large surface among the circumferential side surfaces of the square shell 10, the second surface 12 is a small surface among the circumferential side surfaces of the square shell 10, and the third surface 13 is the bottom surface of the square shell 10.

[0120] The insulating film 20 has a tail area 22 and four folded ears. Specifically, the insulating film 20 will first cover the two first surfaces 11 and the two second surfaces 12 along the circumference of the shell 10 to form a main body area 21 and four folded ears, and the four folded ears are folded toward the bottom surface to cover the bottom surface to form the tail area 22. The four folded ears are configured as two first folded ears 221 and two second folded ears 222. The two first folded ears 221 are respectively connected to one end of the main body area 21 covered on the two first surfaces 11 close to the bottom surface, and the two second folded ears 222 are connected to one end of the main body area 21 covered on the two second surfaces 12 close to the bottom surface. Each first folded ear 221 has two folded portions 2211.

[0121] It should be noted that the present application is also applicable to other encapsulation methods, whose structures and working principles are similar to the above-mentioned round-shaped encapsulation method and U-shaped encapsulation method, and will not be repeated here.

[0122] The crease edge 2212 of the folding portion 2211 refers to the edge where the crease line of the folding portion 2211 is located. For example, when the portion of the first folded ear 221 close to the second folded ear 222 is folded with another portion of the first folded ear 221 to form the folding portion 2211, the position where the crease line formed by folding the portion of the first folded ear 221 close to the second folded ear 222 with another portion of the first folded ear 221 is located is the crease edge 2212. The crease edge 2212 of the folding portion 2211 can be partially exposed on the side surface of the second folded ear 222 facing away from the third surface 13, and the other part is covered by other parts of the insulating film 20; the crease edge 2212 of the folding portion 2211 can also be completely exposed on the side surface of the second folded ear 222 facing away from the third surface 13.

[0123] The fold edge 2212 of the folding portion 2211 is the place closest to the gap between the folding portion 2211 and the second folding ear 222 and the external environment. The fold edge 2212 exposed on the side surface of the second folding ear 222 facing away from the third surface 13 can be understood as the entrance for the electrolyte to enter the gap. Therefore, this entrance is closed, that is, the fold edge 2212 exposed on the side surface of the second folding ear 222 facing away from the third surface 13 is connected to the second folding ear 222 to form a sealing structure. When the battery cell 7 has abnormalities such as electrolyte leakage or thermal runaway, the electrolyte can be blocked outside and the electrolyte is blocked from entering the gap.

[0124] Exemplarily, the folded edge 2212 of the folding portion 2211 and the second folded ear 222 may be welded, for example, by but not limited to heating or hot pressing, etc.; the folded edge 2212 of the folding portion 2211 and the second folded ear 222 may also be bonded.

[0125] In this way, the above technical scheme can cut off the conductive relationship between the gap between the folding portion 2211 and the second folding ear 222 and the external environment, or eliminate the gap between the folding portion 2211 and the second folding ear 222, by welding the second folding ear 222 at least to the fold edge 2212 exposed on the side surface of the second folding ear 222 facing away from the third surface 13. This can not only reduce the risk of insulation failure when abnormalities such as electrolyte leakage or thermal runaway occur in the battery cell 7, thereby improving the reliability of the battery cell 7, but also reduce the overall thickness of the insulating film 20, thereby improving the energy density of the battery cell 7.

[0126] In some embodiments, the entire folded portion 2211 is welded to the second folded ear 222 to eliminate the gap between the folded portion 2211 and the second folded ear 222 , thereby further improving the reliability of the battery cell 7 and further improving the energy density of the battery cell 7 .

[0127] Fig.10This is a schematic side view of another battery cell 7 provided in some embodiments of the present application.

[0128] Continue to refer Fig.10 In some embodiments, the tail region 22 has an indentation 30 , and the indentation 30 at least covers the fold edge 2212 exposed on the side surface of the first fold ear 221 facing away from the third surface 13 .

[0129] For example, the folding portion 2211 and the second folding ear 222 may be welded by hot pressing and an indentation 30 may be formed on the finishing area 22 at the same time. The indentation 30 may facilitate an operator or an identification device to quickly and accurately determine whether the folding portion 2211 and the second folding ear 222 have been welded based on the appearance of the battery cell 7.

[0130] In the manufacturing process of the battery cell 7, there are many links that require hot pressing operations. For example, the stacking or winding of the pole pieces needs to be compacted by hot pressing, the pole pieces need to be dried and compacted by hot pressing after coating, the packaging of the battery cell 7 needs to be hot pressed, etc. Therefore, hot pressing equipment is more commonly used in battery production systems.

[0131] In this way, on the one hand, the above technical solution enables the operator or the identification device to quickly and accurately determine whether the folding portion 2211 and the second folding ear 222 have been welded, thereby improving the overall production efficiency of the battery cell 7; on the other hand, it can utilize the existing hot pressing equipment in the battery production system, which can help reduce costs.

[0132] Fig.11 This is a schematic side view of the structure of another battery cell 7 provided in some embodiments of the present application.

[0133] Continue to refer Fig.11 In some embodiments, the indentation 30 covers the folded portion 2211. By increasing the hot pressing area, the risk of incomplete welding of the fold edge 2212 exposed on the side of the first folded ear 221 facing away from the third surface 13 and the second folded ear 222 due to pressure leakage can be reduced, thereby further improving the reliability of welding.

[0134] In some embodiments, there are multiple folding portions 2211 , and there are multiple indentations 30 , and the number of indentations 30 is not less than the number of folding portions 2211 , and each indentation 30 at least partially overlaps with the folding portion 2211 .

[0135] In this way, the insulating film 20 can be hot-pressed multiple times in sequence to more specifically weld key areas, which can reduce the hot-pressing area while meeting the welding requirements, thereby helping to reduce costs.

[0136] In some embodiments, the outer surface of the housing 10 includes two third surfaces 13, the two third surfaces 13 are arranged opposite to each other, and the second surface 12 connects the two first surfaces 11 and the two third surfaces 13. The main body area 21 includes two first sub-areas and a second sub-area, the two first sub-areas are respectively covered on the two first surfaces 11, and the second sub-area is covered on the second surface 12, and the insulating film 20 includes two tailing areas 22, and the two tailing areas 22 are respectively covered on the two third surfaces 13. Each tailing area 22 includes two first folding ears 221 and a second folding ear 222, the first folding ear 221 is connected to one end of the first sub-area close to the third surface 13, and the two first folding ears 221 located in the same tailing area 22 are respectively folded from the two first sub-areas toward the third surface 13, and the second folding ear 222 is connected to one end of the second sub-area close to the third surface 13, and is folded from the second sub-area toward the third surface 13.

[0137] Exemplarily, the housing 10 is a square housing 10, the two first surfaces 11 can be understood as two large surfaces in the circumferential side of the housing 10, the second surface 12 can be understood as the bottom surface of the housing 10, and the two third surfaces 13 can be understood as two small surfaces in the circumferential side of the housing 10. The insulating film 20 has two tail regions 22 and six folded ears, wherein each tail region 22 is formed by three folded ears.

[0138] As an example, the insulating film 20 may first cover a first surface 11 of the shell 10 to form a first sub-region, then the insulating film 20 is folded toward the second surface 12 and covers the second surface 12 to form a second sub-region, and then the insulating film 20 is folded toward another first surface 11 of the shell 10 to form another first sub-region and six folded ears.

[0139] As another example, the insulating film 20 may first cover the second surface 12 of the housing 10 to form a second sub-region, and then the insulating film 20 may be folded toward the two first surfaces 11 and cover the two first surfaces 11 to form two first sub-regions and six folded ears.

[0140] For ease of description, the two third surfaces 13 are respectively configured as the first facet and the second facet, and the two tail regions 22 are respectively configured as the first tail region and the second tail region. Three of the six folded ears are connected to one end of the main body region 21 close to the first facet and surround the periphery of the first facet, and these three folded ears are folded toward the first facet to cover the first facet to form the first tail region; and the other three of the six folded ears are connected to one end of the main body region 21 close to the second facet and surround the periphery of the second facet, and these three folded ears are folded toward the second facet to cover the second facet to form the second tail region.

[0141] In the first tailing area, two of the three folded ears in the first tailing area are configured as two first folded ears 221, and another of the three folded ears in the first tailing area is configured as a second folded ear 222. The two first folded ears 221 are respectively connected to one end of the main area 21 covering the two first surfaces 11 close to the first small face, and the second folded ear 222 is connected to one end of the main area 21 covering the second surface 12 close to the first small face. Each first folded ear 221 has a folded portion 2211.

[0142] In the second tailing area, two of the three folded ears in the second tailing area are configured as two first folded ears 221, and another of the three folded ears in the second tailing area is configured as a second folded ear 222. The two first folded ears 221 are respectively connected to one end of the main body area 21 covering the two first surfaces 11 close to the first small face, and the second folded ear 222 is connected to one end of the main body area 21 covering the second surface 12 close to the first small face. Each first folded ear 221 has a folded portion 2211.

[0143] The coating method of the above technical solution is conducive to reducing the area of ​​the folded portion 2211 of the tail area 22, thereby reducing the welding difficulty and welding area between the folded portion 2211 and the second folded ear 222, so as to improve the welding efficiency and reduce the cost.

[0144] In some embodiments, the first folded ear 221 further has a notch, which is disposed close to the second folded ear 222. The presence of the notch can further reduce the area of ​​the folded portion 2211 when the first folded ear 221 is affected by the folding of the second folded ear 222 to form the folded portion 2211.

[0145] In some embodiments, two first folded ears 221 located in the same tail region 22 partially overlap.

[0146] Exemplarily, for ease of description, the portion of the first folded ear 221 excluding the folded portion 2211 is configured as the connecting portion 2213. In other words, the portion of the first folded ear 221 that is not folded by itself is configured as the connecting portion 2213. The connecting portion 2213 has a single-layer insulating film 20, and two first folded ears 221 located in the same tailing region 22 partially overlap, so that a stacked structure having multiple layers of insulating films 20 can be formed in the tailing region 22.

[0147] In some examples, in the same tailing region 22, the connection portions 2213 of the two first folded ears 221 partially overlap, and the folded portions 2211 of the two first folded ears 221 do not overlap. In this way, a first stacked structure having two layers of insulating film 20 and a second stacked structure having three layers of insulating film 20 can be formed in the tailing region 22. The first stacked structure is formed by the overlap of the connection portions 2213 of the two first folded ears 221, a portion of the second stacked structure is formed by the overlap of the connection portions 2213 of the two first folded ears 221 and the second folded ears 222, and another portion of the second stacked structure is formed by the overlap of the folded portion 2211 of one first folded ear 221 and the second folded ear 222.

[0148] In some examples, in the same tailing area 22, the connection parts 2213 of the two first folded ears 221 partially overlap, and the folded parts 2211 of the two first folded ears 221 also partially overlap. In this way, a first stacking structure with two layers of insulating film, a second stacking structure with three layers of insulating film, and a third stacking structure with five layers of insulating film can be formed in the tailing area 22. Among them, the first stacking structure is formed by the overlapping of the connection parts 2213 of the two first folded ears 221, a part of the second stacking structure is formed by the overlapping of the connection parts 2213 of the two first folded ears 221 and the second folded ears 222, another part of the second stacking structure is formed by the overlapping of the folded parts 2211 of each first folded ear 221 and the second folded ear 222, and the third stacking structure is formed by the overlapping of the folded parts 2211 and the second folded ears 222 of the two first folded ears 221.

[0149] The above technical solution can reduce the risk of incomplete coverage of the tail area 22 causing part of the outer surface of the shell 10 to be exposed to the external environment by partially overlapping the two first folded ears 221 located in the same tail area 22, thereby improving the coverage effect of the insulating film 20 and thus improving the reliability of the battery cell 7.

[0150] In some embodiments, the overlapping parts of the two first folded ears 221 located in the same tailing area 22 are welded.

[0151] For example, the overlapping parts of the two first folded ears 221 located in the same tailing area 22 may be welded by, but not limited to, heating or hot pressing.

[0152] The above technical solution can reduce the thickness of the overlapping portion of the two first folded ears 221 by welding the overlapping portions of the two first folded ears 221 located in the same tail area 22, thereby facilitating reducing the overall volume of the battery cell 7 to improve the energy density of the battery cell 7.

[0153] Fig.12 This is a schematic side view of another battery cell 7 provided in some embodiments of the present application. Fig.13A schematic side view of the structure of another battery cell 7 provided in some embodiments of the present application.

[0154] Continue to refer Fig.12 and Fig.13 In some embodiments, the battery cell 7 further includes a connector 40 , which at least connects the fold edge 2212 and the second fold ear 222 exposed on the side surface of the second fold ear 222 facing away from the third surface 13 , and the melting point of the connector 40 is lower than the melting point of the insulating film 20 .

[0155] For example, the melting point is the temperature at which a solid changes its physical state from a solid state (melts) to a liquid state. The connector 40 may be disposed between the fold edge 2212 exposed on the side of the second folded ear 222 facing away from the third surface 13 and the second folded ear 222, or the connector 40 may cover the side of the fold edge 2212 exposed on the side of the second folded ear 222 facing away from the third surface 13 facing away from the second folded ear 222.

[0156] Optionally, the connecting member 40 may be made of, but not limited to, polyethylene or polypropylene.

[0157] When the insulating film 20 is subjected to heating or heat pressing, since the melting point of the connector 40 is lower than that of the insulating film 20, the connector 40 will melt before the insulating film 20, and then at least the fold edge 2212 exposed on the side surface of the second fold ear 222 facing away from the third surface 13 will be connected to the second fold ear 222, thereby cutting off the conductive relationship between the gap between the folded portion 2211 and the second fold ear 222 and the external environment, or eliminating the gap between the folded portion 2211 and the second fold ear 222.

[0158] In this way, the above technical solution can effectively reduce the temperature during the welding process and reduce the risk of high-temperature damage to the insulating film 20 by additionally providing a low-melting-point connector 40 while achieving welding of the folding portion 2211 and the second folding ear 222 .

[0159] In some embodiments, part of the connector 40 covers the folded portion 2211. By increasing the coverage area of ​​the connector 40, the risk of incomplete welding of the fold edge 2212 exposed on the side surface of the first folded ear 221 facing away from the third surface 13 and the second folded ear 222 due to incomplete coverage of the connector 40 can be reduced, thereby further improving the reliability of welding.

[0160] Based on the battery cell 7 provided in the embodiment of the present application, the embodiment of the present application also provides a method for manufacturing the battery cell 7. Fig.14 A process flow chart of a method for manufacturing a battery cell 7 provided in some embodiments of the present application. Fig.14As shown, the method for manufacturing the battery cell 7 may include step 01 , step 02 and step 03 .

[0161] Step 01, providing a housing 10, wherein the outer surface of the housing 10 includes two first surfaces 11, a second surface 12 and a third surface 13, the two first surfaces 11 are arranged opposite to each other, the second surface 12 connects the two first surfaces 11, the third surface 13 connects the two first surfaces 11, and the first surface 11, the second surface 12 and the third surface 13 intersect with each other;

[0162] Step 02, providing an insulating film 20, and covering the insulating film 20 on the outer surface of the housing 10, wherein the insulating film 20 is integrally provided and includes a main body area 21 and a tail area 22, the main body area 21 covers the first surface 11 and the second surface 12, the tail area 22 covers the third surface 13 and connects to the main body area 21, the tail area 22 includes a plurality of folded ears, the plurality of folded ears at least partially overlap, the plurality of folded ears include a first folded ear 221 and a second folded ear 222, a portion of the first folded ear 221 is self-folded to form a folded portion 2211 having a plurality of insulating films 20, the folded portion 2211 is stacked on a side of the second folded ear 222 facing away from the third surface 13, and at least a portion of a folded edge 2212 of the folded portion 2211 is exposed on a surface of a side of the second folded ear 222 facing away from the third surface 13;

[0163] Step 03, processing the insulating film 20 so that the second folded ear 222 is at least fused to the fold edge 2212 exposed on the side surface of the second folded ear 222 facing away from the third surface 13.

[0164] The above steps are described in detail below, as shown below.

[0165] First, regarding the above step 01, the outer shell 10 can be square, and the outer shell 10 includes a shell and an end cover, the shell has an opening, and the end cover covers the opening. The first surface 11, the second surface 12 and the third surface 13 are all arranged on the shell. The first surface 11 can be understood as a large surface on the circumferential side of the shell, wherein the circumferential side refers to the surface along the opening, and the large surface means the surface with a larger area on the circumferential side of the shell. One of the second surface 12 and the third surface 13 can be understood as a small surface on the circumferential side of the shell, and the other of the second surface 12 and the third surface 13 can be understood as the bottom surface of the shell, wherein the small surface means the surface with a smaller area on the circumferential side of the shell, and the bottom surface refers to the surface on the shell opposite to the opening.

[0166] Next, in step 02, the insulating film 20 may be coated on the housing 10 in a U-shaped coating method or in a U-shaped coating method.

[0167] In some examples, when the square housing 10 is coated with the insulating film 20 in a round-shaped coating manner, the first surface 11 is a large surface, the second surface 12 is a small surface, and the third surface 13 is a bottom surface.

[0168] In some examples, when the square housing 10 is coated with the insulating film 20 in a U-shaped coating manner, the first surface 11 is a large surface, the second surface 12 is a bottom surface, and the third surface 13 is a small surface.

[0169] Next, in relation to the above step 03, the crease edge 2212 of the folding portion 2211 refers to the edge where the crease line of the folding portion 2211 is located. For example, when the portion of the first folded ear 221 close to the second folded ear 222 is folded with another portion of the first folded ear 221 to form the folding portion 2211, the position where the crease line formed by folding the portion of the first folded ear 221 close to the second folded ear 222 with another portion of the first folded ear 221 is located is the crease edge 2212. The crease edge 2212 of the folding portion 2211 may be partially exposed on the side surface of the second folded ear 222 facing away from the third surface 13, and the other part is covered by other parts of the insulating film 20; the crease edge 2212 of the folding portion 2211 may also be completely exposed on the side surface of the second folded ear 222 facing away from the third surface 13.

[0170] The fold edge 2212 of the folding portion 2211 is the place closest to the gap between the folding portion 2211 and the second folding ear 222 and the external environment. The fold edge 2212 exposed on the side surface of the second folding ear 222 facing away from the third surface 13 can be understood as the entrance for the electrolyte to enter the gap. Therefore, this entrance is closed, that is, the fold edge 2212 exposed on the side surface of the second folding ear 222 facing away from the third surface 13 is connected to the second folding ear 222 to form a sealing structure. When the battery cell 7 has abnormalities such as electrolyte leakage or thermal runaway, the electrolyte can be blocked outside and the electrolyte is blocked from entering the gap.

[0171] Exemplarily, the folded edge 2212 of the folding portion 2211 and the second folded ear 222 may be welded, for example, by but not limited to heating or hot pressing, etc.; the folded edge 2212 of the folding portion 2211 and the second folded ear 222 may also be bonded.

[0172] In this way, the above technical scheme can cut off the conductive relationship between the gap between the folding portion 2211 and the second folding ear 222 and the external environment, or eliminate the gap between the folding portion 2211 and the second folding ear 222, by welding the second folding ear 222 at least to the fold edge 2212 exposed on the side surface of the second folding ear 222 facing away from the third surface 13. This can not only reduce the risk of insulation failure when abnormalities such as electrolyte leakage or thermal runaway occur in the battery cell 7, thereby improving the reliability of the battery cell 7, but also reduce the overall thickness of the insulating film 20, thereby improving the energy density of the battery cell 7.

[0173] In some embodiments, the processing of the insulating film 20 in step 03 includes: hot pressing the insulating film 20 to form an indentation 30 .

[0174] For example, the folding portion 2211 and the second folding ear 222 may be welded by hot pressing and an indentation 30 may be formed on the finishing area 22 at the same time. The indentation 30 may facilitate an operator or an identification device to quickly and accurately determine whether the folding portion 2211 and the second folding ear 222 have been welded based on the appearance of the battery cell 7.

[0175] In the manufacturing process of the battery cell 7, there are many links that require hot pressing operations. For example, the stacking or winding of the pole pieces needs to be compacted by hot pressing, the pole pieces need to be dried and compacted by hot pressing after coating, the packaging of the battery cell 7 needs to be hot pressed, etc. Therefore, hot pressing equipment is more commonly used in battery production systems.

[0176] In this way, on the one hand, the above technical solution enables the operator or the identification device to quickly and accurately determine whether the folding portion 2211 and the second folding ear 222 have been welded, thereby improving the overall production efficiency of the battery cell 7; on the other hand, it can utilize the existing hot pressing equipment in the battery production system, which can help reduce costs.

[0177] In some embodiments, the processing of the insulating film 20 in step 03 includes: performing multiple hot pressing on the insulating film 20 to form multiple indentations 30 .

[0178] By performing multiple heat pressing operations on the insulating film 20 in sequence, the key areas can be welded more specifically, which can reduce the heat pressing area while meeting the welding requirements, thereby helping to reduce costs.

[0179] In some embodiments, the duration of the hot pressing is no more than 5 seconds, which can effectively reduce the risk of the insulating film 20 being damaged during the hot pressing process and the risk of the battery cell 7 being damaged due to excessive heating.

[0180] In some embodiments, the processing of the insulating film 20 in step 03 includes:

[0181] Providing a connecting member 40, at least a portion of which is disposed between the second folded ear 222 and a fold edge 2212 exposed on a side surface of the second folded ear 222 facing away from the third surface 13, wherein the melting point of the connecting member 40 is lower than the melting point of the insulating film 20;

[0182] The connecting member 40 is heated to melt the connecting member 40 and connect at least the second folded ear 222 and the fold edge 2212 exposed on the side surface of the second folded ear 222 facing away from the third surface 13 .

[0183] For example, the melting point is the temperature at which a solid changes its physical state from a solid state (melts) to a liquid state. The connector 40 may be disposed between the fold edge 2212 exposed on the side of the second folded ear 222 facing away from the third surface 13 and the second folded ear 222, or the connector 40 may cover the side of the fold edge 2212 exposed on the side of the second folded ear 222 facing away from the third surface 13 facing away from the second folded ear 222.

[0184] Optionally, the connecting member 40 may be made of, but not limited to, polyethylene or polypropylene.

[0185] When the insulating film 20 is subjected to heating or heat pressing, since the melting point of the connector 40 is lower than that of the insulating film 20, the connector 40 will melt before the insulating film 20, and then at least the fold edge 2212 exposed on the side surface of the second fold ear 222 facing away from the third surface 13 will be connected to the second fold ear 222, thereby cutting off the conductive relationship between the gap between the folded portion 2211 and the second fold ear 222 and the external environment, or eliminating the gap between the folded portion 2211 and the second fold ear 222.

[0186] In this way, the above technical solution can effectively reduce the temperature during the welding process and reduce the risk of high-temperature damage to the insulating film 20 by additionally providing a low-melting-point connector 40 while achieving welding of the folding portion 2211 and the second folding ear 222 .

[0187] In some embodiments, the processing of the insulating film 20 in step 03 includes:

[0188] Providing a connecting member 40, and covering the connecting member 40 on the side of the folding portion 2211 facing away from the second folding ear 222, wherein the melting point of the connecting member 40 is lower than the melting point of the insulating film 20;

[0189] The connecting member 40 is heated to melt the connecting member 40 and connect at least the second folded ear 222 and the fold edge 2212 exposed on the side surface of the second folded ear 222 facing away from the third surface 13 .

[0190] By increasing the coverage area of ​​the connector 40, the risk of incomplete welding of the fold edge 2212 exposed on the side surface of the first fold ear 221 facing away from the third surface 13 and the second fold ear 222 due to incomplete coverage of the connector 40 can be reduced, thereby further improving the reliability of welding.

[0191] It can be understood that the manufacturing method of the battery cell 7 of the embodiment of the present application can be used to implement the battery cell 7 provided by any of the embodiments of the present application mentioned above. The specific details of the battery cell 7 implemented by the various steps of the manufacturing method of the battery cell 7 can be found in the description of the corresponding parts of the battery cell 7 provided in the embodiments of the present application mentioned above. For the sake of brevity, they will not be repeated here.

[0192] In addition, the corresponding structural features of the battery cell 7 provided in any of the above embodiments of the present application can be prepared using the same or similar preparation method mentioned in the embodiments of the present application, and for the sake of brevity, they will not be repeated here.

[0193] According to some embodiments of the present application, the present application further provides a battery device, comprising a battery cell 7 of any of the above solutions.

[0194] According to some embodiments of the present application, the present application further provides an electrical device, comprising a battery cell 7 according to any of the above schemes, and the battery cell 7 is used to provide electrical energy.

[0195] In order to better understand the battery cell 7 provided in the embodiment of the present application, based on the same inventive concept, an embodiment of the above-mentioned battery cell 7 in actual application is provided here for illustration.

[0196] An embodiment of the present application provides a battery cell 7, which includes a shell 10 and an insulating film 20. The outer surface of the shell 10 includes two first surfaces 11, a second surface 12 and two third surfaces 13. The two first surfaces 11 are arranged opposite to each other, and the two third surfaces 13 are arranged opposite to each other. The second surface 12 connects the two first surfaces 11 and the two third surfaces 13, and each third surface 13 connects the two first surfaces 11. The first surface 11, the second surface 12 and the third surface 13 intersect with each other.

[0197] The insulating film 20 is integrally provided and includes a main body region 21 and two tail regions 22. The main body region 21 includes two first sub-regions and a second sub-region. The two first sub-regions cover the two first surfaces 11 respectively, and the second sub-region covers the second surface 12. The two tail regions 22 cover the two third surfaces 13 respectively and are connected to the main body region 21. Each tail region 22 includes two first folded ears 221 and a second folded ear 222. The first folded ear 221 and the second folded ear 222 at least partially overlap. The first folded ear 221 is connected to one end of the first sub-region close to the third surface 13. The two first folded ears 221 located in the same tail region 22 are folded relatively from the two first sub-regions toward the third surface 13 respectively. The second folded ear 222 is connected to one end of the second sub-region close to the third surface 13 and is folded from the second sub-region toward the third surface 13.

[0198] A portion of the first fold ear 221 is self-folded to form a folding portion 2211 having a multi-layer insulating film 20, and the folding portion 2211 is stacked on the side of the second fold ear 222 facing away from the third surface 13, and at least a portion of the folding edge 2212 of the folding portion 2211 is exposed on the side surface of the second fold ear 222 facing away from the third surface 13, and the second fold ear 222 is at least welded to the folding edge 2212 exposed on the side surface of the second fold ear 222 facing away from the third surface 13.

[0199] In this way, the above technical scheme can cut off the conductive relationship between the gap between the folding portion 2211 and the second folding ear 222 and the external environment, or eliminate the gap between the folding portion 2211 and the second folding ear 222, by welding the second folding ear 222 at least to the fold edge 2212 exposed on the side surface of the second folding ear 222 facing away from the third surface 13. This can not only reduce the risk of insulation failure when abnormalities such as electrolyte leakage or thermal runaway occur in the battery cell 7, thereby improving the reliability of the battery cell 7, but also reduce the overall thickness of the insulating film 20, thereby improving the energy density of the battery cell 7.

[0200] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application may be combined with each other.

[0201] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A battery cell, characterized in that: include: A shell, wherein the outer surface of the shell comprises two first surfaces, a second surface and a third surface, the two first surfaces are arranged opposite to each other, the second surface connects the two first surfaces, the third surface connects the two first surfaces, and the first surface, the second surface and the third surface intersect with each other; An insulating film is integrally provided and includes a main region and a tail region, wherein the main region covers the two first surfaces and the second surface, and the tail region covers the third surface and is connected to the main region; Wherein, the tail area includes a plurality of folded ears, the plurality of folded ears at least partially overlap, the plurality of folded ears include a first folded ear and a second folded ear, a portion of the first folded ear is self-folded to form a folded portion having multiple layers of the insulating film, the folded portion is stacked on a side of the second folded ear facing away from the third surface, and at least a portion of the folded edge of the folded portion is exposed on a side of the second folded ear facing away from the third surface, and the second folded ear is at least welded to the folded edge exposed on a side of the second folded ear facing away from the third surface; The tail area has an indentation, and the indentation at least covers the fold edge exposed on the surface of the first folded ear facing away from the third surface; The battery cell further comprises a connector, which at least connects the fold edge and the second fold ear exposed on a surface of the second fold ear facing away from the third surface, and the melting point of the connector is lower than the melting point of the insulating film.

2. The battery cell according to claim 1, characterized in that: The entire folded portion is welded to the second folded ear.

3. The battery cell according to claim 1, characterized in that: The indentation covers the folded portion.

4. The battery cell according to claim 1, characterized in that: There are multiple folding portions, there are multiple indentations, and the number of the indentations is not less than the number of the folding portions, and each of the indentations at least partially overlaps with the folding portion.

5. The battery cell according to claim 1, characterized in that: The outer surface of the housing includes two third surfaces, the two third surfaces are arranged opposite to each other, and the second surface connects the two first surfaces and the two third surfaces; The main body region includes two first sub-regions and a second sub-region, the two first sub-regions respectively cover the two first surfaces, the second sub-region covers the second surface, and the insulating film includes two tail regions, the two tail regions respectively cover the two third surfaces; Each of the tail areas includes two first folded ears and the second folded ears, the first folded ear is connected to one end of the first sub-area close to the third surface, the two first folded ears located in the same tail area are respectively folded from the two first sub-areas toward the third surface, and the second folded ear is connected to one end of the second sub-area close to the third surface and is folded from the second sub-area toward the third surface.

6. The battery cell according to claim 5, characterized in that: The two first folded ears located in the same tailing area are partially overlapped.

7. The battery cell according to claim 6, characterized in that: The overlapping parts of the two first folded ears located in the same tailing area are welded.

8. The battery cell according to claim 1, characterized in that: Part of the connecting member covers the folded portion.

9. A method for manufacturing a battery cell, characterized in that: include: A housing is provided, wherein an outer surface of the housing includes two first surfaces, a second surface and a third surface, the two first surfaces are arranged opposite to each other, the second surface connects the two first surfaces, the third surface connects the two first surfaces, and the first surface, the second surface and the third surface intersect with each other; Providing an insulating film, and coating the insulating film on the outer surface of the shell, wherein the insulating film is integrally provided and includes a main body area and a tail area, the main body area covers the first surface and the second surface, the tail area covers the third surface and connects to the main body area, the tail area includes a plurality of folded ears, the plurality of folded ears at least partially overlap, the plurality of folded ears include a first folded ear and a second folded ear, a portion of the first folded ear is self-folded to form a folded portion having multiple layers of the insulating film, the folded portion is stacked on a side of the second folded ear facing away from the third surface, and at least a portion of the folded edge of the folded portion is exposed on a side of the second folded ear facing away from the third surface; The insulating film is processed so that the second folded ear is at least welded to the fold edge exposed on the side of the second folded ear facing away from the third surface; Wherein, the processing of the insulating film comprises: Hot pressing the insulating film to form an indentation; Wherein, the processing of the insulating film comprises: Providing a connecting member, disposing at least a portion of the connecting member between the second folded ear and the fold edge exposed on a side surface of the second folded ear facing away from the third surface, wherein the melting point of the connecting member is lower than the melting point of the insulating film; The connecting member is heated to melt the connecting member and connect at least the second folded ear and the fold edge exposed on a side surface of the second folded ear facing away from the third surface.

10. The method for manufacturing a battery cell according to claim 9, characterized in that: The step of hot pressing the insulating film and forming an indentation comprises: The insulating film is subjected to heat pressing multiple times to form a plurality of the indentations.

11. The method for manufacturing a battery cell according to claim 9, characterized in that: The duration of the heat pressing does not exceed 5 seconds.

12. A battery device, characterized in that: The invention comprises a plurality of battery cells according to any one of claims 1 to 8.

13. An electrical device, characterized in that: The invention comprises a battery cell as claimed in any one of claims 1 to 8, wherein the battery cell is used to provide electrical energy.

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