Battery cell, battery, electric device, and method and apparatus for manufacturing battery cell

Abstract

The embodiment of the application relates to the battery technical field, and provides a battery monomer, a battery, an electric device, and a method and equipment for preparing the battery monomer. The battery monomer comprises a shell, an electrode assembly arranged in the shell, the electrode assembly comprising a positive electrode sheet and a negative electrode sheet, the positive electrode sheet and the negative electrode sheet being laminated and wound to form a winding structure, the electrode assembly comprising a flat area and a bending area, and the bending area being located at an end of the flat area along a first direction; and a support, the support being arranged in the shell and located at a side of the electrode assembly, and the support being used for reducing an expansion space of an innermost layer sheet of the electrode assembly located at the bending area along a thickness direction of the electrode assembly. In the above manner, the innermost layer sheet of the electrode assembly located at the bending area is not prone to wrinkling, lithium ions are prevented from being deposited at the wrinkling position, heat runaway caused by lithium precipitation is prevented from being triggered, and the safety of the battery monomer is improved.

Description

Technical Field

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

[0002] Battery cells are widely used in electronic devices such as mobile phones, laptops, electric vehicles, electric cars, electric airplanes, electric ships, electric toy cars, electric toy ships, electric toy airplanes, and power tools. Battery cells can include nickel-cadmium battery cells, nickel-metal hydride battery cells, lithium-ion battery cells, and rechargeable alkaline zinc-manganese battery cells, among others.

[0003] Safety is a critical issue in the development of battery technology, especially when a short circuit occurs within a single battery cell, which can easily lead to serious safety accidents. Therefore, reducing the probability of internal short circuits in battery cells to improve their safety performance has been a long-standing and important concern in this field. Summary of the Invention

[0004] In view of the above problems, embodiments of this application provide a battery cell, a battery, an electrical device, and a method and apparatus for preparing a battery cell, which can reduce the probability of internal short circuits in the battery cell and improve the safety performance of the battery cell.

[0005] According to a first aspect of the present application, a battery cell is provided, comprising: a housing; an electrode assembly disposed within the housing, the electrode assembly including a positive electrode and a negative electrode, the positive electrode and the negative electrode being stacked and wound to form a wound structure, the electrode assembly including a straight region and a bent region, the bent region being located at the end of the straight region along a first direction; and a support member disposed within the housing and located on the side of the electrode assembly, the support member being used to reduce the expansion space of the innermost electrode of the electrode assembly located in the bent region along the thickness direction of the electrode assembly.

[0006] In the battery cell of this application embodiment, by providing a support member on the side of the electrode assembly inside the casing, the expansion space of the innermost electrode sheet of the electrode assembly located in the bending area along the thickness direction of the electrode assembly can be reduced. During the charging and discharging process of the battery cell, the innermost electrode sheet of the electrode assembly located in the bending area is less likely to wrinkle, preventing lithium ions from depositing at the wrinkled area, which could lead to lithium plating triggering thermal runaway and improve the safety of the battery cell.

[0007] In some embodiments, at least a portion of the support member is located at the boundary between the bent area and the straight area.

[0008] By positioning the support at least part of it at the junction of the bending and straight areas, the expansion space along the thickness direction of the electrode assembly can be reduced in the part of the innermost electrode that is prone to wrinkling. This makes the electrode less prone to wrinkling and prevents lithium ions from depositing at the wrinkled areas, which could lead to lithium plating and trigger thermal runaway.

[0009] In some embodiments, along the thickness direction, the largest part of the support corresponds to the corner of the innermost electrode and abuts against the electrode assembly.

[0010] Setting the largest dimension of the support to correspond to the corner of the innermost electrode and having the support abut against the electrode assembly can reduce the expansion space along the thickness direction of the electrode assembly at the corner of the innermost electrode, making this part of the electrode less prone to wrinkling and preventing lithium ions from depositing at the wrinkled area, which could lead to lithium plating triggering thermal runaway.

[0011] In some embodiments, along the second direction, both ends of the support are flush with the ends of the negative electrode sheet, and the second direction is perpendicular to both the first direction and the thickness direction.

[0012] Since the two ends of the support are flush with the ends of the negative electrode sheet, that is, the height of the support is the same as the height of the negative electrode sheet and the position is the same in the second direction, the support can reduce the expansion space of the innermost electrode sheet of the electrode assembly located in the bending area along the thickness direction of the electrode assembly in the second direction, and can also prevent the support from protruding from the negative electrode sheet, increasing the weight of the battery cell and reducing the energy density of the battery cell.

[0013] In some embodiments, the support member includes a first support portion, a second support portion, and a connecting portion, wherein the first support portion and the second support portion are respectively located at both ends of the support member, and the connecting portion is used to connect the first support portion and the second support portion; the bending area includes a first bending area and a second bending area, wherein at least a portion of the first support portion corresponds to the position of the first bending area, and at least a portion of the second support portion corresponds to the position of the second bending area.

[0014] By setting a first support portion and a second support portion corresponding to the first bending area and the second bending area respectively, the expansion space of the innermost electrode sheet at both ends along the thickness direction of the electrode assembly can be reduced, making the electrode sheet less prone to wrinkling. Furthermore, by setting a connection portion between the first support portion and the second support portion, the structural strength of the support member can be improved.

[0015] In some embodiments, the connecting portion is a hollow structure, used to provide expansion space for the flat area.

[0016] If the expansion of the electrode sheet in the thickness direction in the flat area is suppressed, the electrolyte in the electrode assembly will be squeezed out, affecting the transfer of lithium ions between the positive and negative electrodes, resulting in large-area lithium plating, which can trigger thermal runaway and affect the safety of the battery cell. By setting the connection part as a hollow structure, expansion space can be reserved in the thickness direction for the flat area of ​​the electrode assembly to prevent lithium plating and thus reduce the impact on the safety of the battery cell.

[0017] In some embodiments, the connecting portion includes a first connecting portion and a second connecting portion disposed along a second direction, wherein the hollow structure is formed between the first connecting portion and the second connecting portion, and the second direction is perpendicular to both the first direction and the thickness direction.

[0018] The first and second connecting parts arranged along the second direction can improve the structural strength of the support and prevent the support frame from collapsing.

[0019] In some embodiments, the connecting portion includes a first connecting portion and a second connecting portion disposed along the thickness direction, wherein the sides of the first connecting portion and the second connecting portion near the electrode assembly are flush with the sides of the first support portion and the second support portion near the electrode assembly.

[0020] By providing a first connecting portion and a second connecting portion along the thickness direction, a hollow structure is formed between the first connecting portion and the second connecting portion, which can reserve expansion space in the thickness direction for the flat area of ​​the electrode assembly, preventing lithium plating and thus reducing the impact on the safety of the battery cell. The sides of the first connecting portion and the second connecting portion near the electrode assembly are flush with the sides of the first support portion and the second support portion near the electrode assembly, making the side of the entire support member near the electrode assembly planar. This can reduce stress concentration at the contact point between the sides of the first support portion and the second support portion and the electrode assembly, thereby reducing damage to the electrode assembly that the support portion contacts, preventing positive and negative electrode plates from overlapping, and reducing the risk of internal short circuits in the battery cell.

[0021] In some embodiments, the outer surface of the support member that contacts the electrode assembly is an arc surface.

[0022] By setting the outer surface of the support member that contacts the electrode assembly as an arc surface, compared with the support member with sharp edges on the sides, the stress concentration at the contact position between the sides of the first support part and the electrode assembly can be further reduced, thereby avoiding damage to the electrode assembly that the support part contacts, preventing the positive and negative electrode sheets from overlapping, and reducing the risk of internal short circuit in the battery cell.

[0023] In some embodiments, the battery cell includes a plurality of electrode assemblies arranged side-by-side within the housing along the thickness direction, wherein the support is disposed between the housing and the electrode assemblies adjacent to the housing in the thickness direction.

[0024] In some embodiments, the battery cell includes a plurality of electrode assemblies arranged side by side within the housing along the thickness direction, and the support is disposed between two adjacent electrode assemblies.

[0025] By placing a support between two adjacent electrode assemblies in a plurality of electrode assemblies, a single support can prevent the innermost electrode sheets of the two electrode assemblies located on either side of it from wrinkling, thereby achieving the same effect with fewer supports and reducing the weight of the battery cell.

[0026] In some embodiments, the support is fixed to the side of the electrode assembly by adhesive bonding, or the support is fixed to the side of the electrode assembly by a snap-fit ​​fastener.

[0027] By using snap-fit ​​fasteners, the support can be fixed to the side of the electrode assembly, preventing it from collapsing or shifting relative to the electrode assembly during use. This would reduce the suppression effect on wrinkling of the innermost electrode sheet in the bending area of ​​the electrode assembly. The snap-fit ​​fastener fixation method improves the structural strength of the support. By attaching the support to the side of the electrode assembly, it is also prevented from collapsing or shifting relative to the electrode assembly during use. Moreover, the attachment method can reduce the weight of the sandwich unit and has a smaller impact on the energy density of the battery cell.

[0028] In some embodiments, the support member is provided with a through hole for the electrolyte to pass through in the second direction, and the second direction is perpendicular to both the first direction and the thickness direction.

[0029] Because the support member in the second direction has a through hole for the electrolyte to pass through, the electrolyte can flow from the bottom to the top of the battery cell through the through hole, which improves the wetting effect of the electrolyte on the electrode assembly and ensures the charging and discharging performance of the battery cell.

[0030] In some embodiments, the electrode assembly further includes a diaphragm for isolating the positive electrode and the negative electrode, and the support is one or more diaphragms located outside the electrode assembly. The one or more diaphragms have through holes extending along the thickness direction, and the through holes are provided corresponding to the flat region.

[0031] By winding one or more layers of separator as a support on the outside of the electrode assembly, the expansion space of the innermost electrode sheet in the bending area along the thickness direction of the electrode assembly can be reduced. By opening through holes in this separator as a support, expansion space in the thickness direction can be reserved for the flat area of ​​the electrode assembly to prevent lithium plating and thus reduce the impact on the safety of the battery cell. In addition, directly using the separator as a support can simplify the components and reduce the difficulty of processing and assembly.

[0032] According to a second aspect of the embodiments of this application, a battery is provided, including the battery cell of the above embodiments.

[0033] According to a third aspect of the present application, an electrical device is provided, including a battery cell as described above, wherein the battery cell is used to provide electrical energy.

[0034] According to a fourth aspect of the present application, a method for preparing a battery cell is provided, comprising: providing a housing; providing an electrode assembly, the electrode assembly including a positive electrode and a negative electrode, the positive electrode and the negative electrode being stacked and wound to form a wound structure, the electrode assembly including a straight region and a bent region, the bent region being located at the end of the straight region along a first direction; providing a support member; disposing the electrode assembly and the support member within the housing, and positioning the support member on the side of the electrode assembly, such that the support member can reduce the expansion space of the innermost electrode of the electrode assembly located in the bent region along the thickness direction of the electrode assembly.

[0035] According to a fifth aspect of the present application, an apparatus for preparing a battery cell is provided, comprising: a first providing device configured to provide a housing; a second providing device configured to provide an electrode assembly, the electrode assembly including a positive electrode and a negative electrode, the positive electrode and the negative electrode being stacked and wound to form a wound structure, the electrode assembly including a straight region and a bent region, the bent region being located at an end of the straight region along a first direction; a third providing device configured to provide a support member; and an assembly device configured to dispose of the electrode assembly and the support member within the housing, and to position the support member on a side of the electrode assembly such that the support member can reduce the expansion space of the innermost electrode of the electrode assembly located in the bent region along the thickness direction of the electrode assembly.

[0036] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0037] The features, advantages, and technical effects of exemplary embodiments of this application will now be described with reference to the accompanying drawings.

[0038] Figure 1 These are schematic diagrams of the vehicle structure provided in some embodiments of this application;

[0039] Figure 2 These are exploded schematic diagrams of batteries provided in some embodiments of this application;

[0040] Figure 3 yes Figure 2 A schematic diagram of the battery module in the diagram;

[0041] Figure 4 These are exploded schematic diagrams of individual battery cells provided in some embodiments of this application;

[0042] Figure 5 yes Figure 4 A schematic diagram of the cross-section of the electrode assembly in the XOY plane;

[0043] Figure 6 yes Figure 4 A schematic diagram showing the fit between the middle electrode assembly and the support component;

[0044] Figure 7 This is a schematic diagram illustrating the engagement of electrode assemblies and support members provided in some embodiments of this application;

[0045] Figure 8 These are schematic diagrams of the support structure provided in some embodiments of this application;

[0046] Figure 9 yes Figure 8 The diagram shows the cooperation between the support member and the electrode assembly.

[0047] Figure 10 These are schematic diagrams of the support structure provided in some embodiments of this application;

[0048] Figure 11 yes Figure 10 The diagram shows the cooperation between the support member and the electrode assembly.

[0049] Figure 12 These are schematic diagrams of the support structure provided in some embodiments of this application;

[0050] Figure 13 yes Figure 12 The diagram shows the cooperation between the support member and the electrode assembly.

[0051] Figure 14 This is a schematic diagram of the cooperation between the electrode assembly and the support in a battery cell provided in some embodiments of this application;

[0052] Figure 15This is a schematic diagram of the cooperation between the electrode assembly and the support in a battery cell provided in some embodiments of this application;

[0053] Figure 16 This is a schematic diagram of the cooperation between the electrode assembly and the support in a battery cell provided in some embodiments of this application;

[0054] Figure 17 This is a schematic diagram of the cooperation between the electrode assembly and the support in a battery cell provided in some embodiments of this application;

[0055] Figure 18 This is a schematic diagram of the cooperation between the electrode assembly and the support in a battery cell provided in some embodiments of this application;

[0056] Figure 19 This is a schematic diagram of the cooperation between the electrode assembly and the support in a battery cell provided in some embodiments of this application;

[0057] Figure 20 These are exploded schematic diagrams of individual battery cells provided in some embodiments of this application;

[0058] Figure 21 yes Figure 20 Assembly diagram of the fastener and electrode assembly;

[0059] Figure 22 yes Figure 21 Top view of the fastener and electrode assembly in the XOY plane;

[0060] Figure 23 yes Figure 22 Schematic diagram of the cross-sectional structure in the AA direction;

[0061] Figure 24 These are exploded schematic diagrams of individual battery cells provided in some embodiments of this application;

[0062] Figure 25 These are exploded schematic diagrams of individual battery cells provided in some embodiments of this application;

[0063] Figure 26 This is a schematic flowchart of a method for preparing a battery cell provided in some embodiments of this application;

[0064] Figure 27 This is a schematic diagram of the structure of an apparatus for preparing battery cells provided in some embodiments of this application.

[0065] The accompanying drawings are not necessarily drawn to scale.

[0066] Reference numerals: 1-Vehicle, 2-Battery, 3-Controller, 4-Motor, 5-Housing, 6-Battery Module; 51-First Housing Section, 52-Second Housing Section, 53-Accommodation Space; 7-Battery Cell; 71-Housing Shell; 72-Electrode Assembly, 721-Positive Electrode, 722-Negative Electrode, 722a-Innermost Electrode, 723-Separator, 724-Through Hole, R1-Straight Region, R2-Bending Region, R 21 -First bend area, R 22 - Second bending area; 73- Support member, 731- First support part, 732- Second support part, 733- Connecting part, 733a- First connecting part, 733b- Second connecting part, 734- Fastener; 74- End cap; 8- Equipment for preparing battery cells, 81- First supplying device, 82- Second supplying device, 83- Third supplying device, 84- Assembly device; P 1, P2 - Corner of the innermost electrode; P3 - Maximum size of the support; S - Adhesive surface on the support; X - First direction; Y - Thickness direction of the electrode assembly; Z - Second direction. Detailed Implementation

[0067] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0068] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0069] It should be noted that, unless otherwise stated, the technical or scientific terms used in the embodiments of this application should have the ordinary meaning understood by those skilled in the art to which the embodiments of this application pertain.

[0070] In the description of the embodiments of this application, the technical terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0071] Furthermore, technical terms such as "first" and "second" are used for descriptive purposes only and should not be interpreted as indicating or implying relative importance or implicitly specifying the number of technical features indicated, nor are they used to describe a specific order or primary / secondary relationship.

[0072] In this article, the term "and / or" simply describes the relationship between related objects, indicating that three relationships can exist. For example, "A and / or B" can represent three cases: A exists alone, A and B exist simultaneously, and B exists alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0073] In this application, "multiple" means two or more; similarly, "multiple groups" means two or more groups, and "multiple pieces" means two or more pieces, unless otherwise explicitly specified.

[0074] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0075] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment that is mutually exclusive with other embodiments. Those skilled in the art will understand that the embodiments described herein can be combined with other embodiments.

[0076] A battery electrode assembly typically includes a positive electrode, a negative electrode, and a separator. These are stacked and wound around a winding axis to form a wound structure. The wound electrode assembly includes a flat region and bent regions at both ends of the flat region. The positive electrode includes a positive current collector and a positive active material layer, which is coated on the surface of the positive current collector. Taking a lithium-ion battery as an example, the positive current collector can be made of aluminum, and the positive active material layer includes a positive active material, such as lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide. The negative electrode includes a negative current collector and a negative active material layer, which is coated on the surface of the negative current collector. The negative current collector can be made of copper, and the negative active material layer includes a negative active material, such as carbon or silicon. The separator can be made of PP or PE, etc.

[0077] During charging and discharging, lithium ions embedding into the electrode plates causes changes in the electrode lattice parameters, resulting in expansion of the electrode plates in the thickness direction. This expansion and contraction occur with the frequency of charging and discharging. In existing battery cell structures, there is generally a gap between the electrode assembly and the casing in the thickness direction of the electrode assembly. This gap prevents the electrode assembly from being effectively constrained in the thickness direction, allowing for expansion. Expansion of the innermost electrode plate in the bending region can easily cause wrinkling of that part of the electrode plate. Lithium ions tend to deposit at the wrinkled areas, leading to lithium plating. The deposited lithium dendrites may react with the electrolyte, generating a large amount of heat locally or puncturing the separator, causing a short circuit between the positive and negative electrodes. This can result in thermal runaway of the battery cell and lead to a safety accident.

[0078] In view of this, this application provides a battery cell that, by providing a support member on the side of the electrode assembly inside the casing, can reduce the expansion space of the innermost electrode sheet of the electrode assembly located in the bending area along the thickness direction of the electrode assembly. During the charging and discharging process of the battery cell, the innermost electrode sheet of the electrode assembly located in the bending area is less likely to wrinkle, preventing lithium ions from depositing at the wrinkled area, which could lead to lithium plating triggering thermal runaway and improve the safety of the battery cell.

[0079] The battery cells described in the embodiments of this application are applicable to batteries and electrical devices that use batteries.

[0080] Electrical devices can include vehicles, mobile phones, portable devices, laptops, ships, spacecraft, electric toys, and power tools, etc. Vehicles can be gasoline-powered cars, natural gas-powered cars, or new energy vehicles; new energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. Spacecraft include airplanes, rockets, space shuttles, and spacecraft, etc. Electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc. This application does not impose any special limitations on the above-mentioned electrical devices.

[0081] For ease of explanation, the following embodiments will use a vehicle as an example of an electrical device.

[0082] Please see Figure 1 , Figure 1 The diagram shows the structural features of a vehicle as provided in some embodiments of this application. Figure 1 As shown, a battery 2 is installed inside the vehicle 1. Battery 2 refers to a single physical module comprising one or more individual battery cells to provide higher voltage and capacity. For example, the battery 2 mentioned in this application may include a battery module or battery pack. Battery 2 may be located at the bottom, front, or rear of the vehicle 1. Battery 2 can be used to power the vehicle 1; for example, battery 2 can serve as the operating power source for the vehicle 1. The vehicle 1 may also include a controller 3 and a motor 4. The controller 3 is used to control the battery 2 to supply power to the motor 4, for example, to meet the power needs of the vehicle 1 during starting, navigation, and driving.

[0083] In some embodiments of this application, the battery 2 can not only serve as the operating power source for the vehicle 1, but also as the driving power source for the vehicle 1, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1.

[0084] Please see Figure 2 , Figure 2 This is an exploded schematic diagram of a battery provided for some embodiments of this application.

[0085] like Figure 2 As shown, battery 2 includes housing 5 and battery module 6, with battery module 6 housed inside housing 5.

[0086] The housing 5 is used to house the battery module 6, and the housing 5 can have various structures. In some embodiments, the housing 5 may include a first housing portion 51 and a second housing portion 52, which overlap each other, and together define a receiving space 53 for housing the battery module 6. The second housing portion 52 may be a hollow structure with one end open, and the first housing portion 51 may be a plate-like structure, with the first housing portion 51 covering the open side of the second housing portion 52 to form a housing 5 with the receiving space 53; alternatively, both the first housing portion 51 and the second housing portion 52 may be hollow structures with one side open, with the open side of the first housing portion 51 covering the open side of the second housing portion 52 to form a housing 5 with the receiving space 53. Of course, the first housing portion 51 and the second housing portion 52 can be various shapes, such as cylinders, cuboids, etc.

[0087] To improve the sealing performance after the first housing part 51 and the second housing part 52 are connected, a sealing element, such as sealant or sealing ring, can also be provided between the first housing part 51 and the second housing part 52.

[0088] Assuming that the first box part 51 covers the top of the second box part 52, the first box part 51 can also be called the upper box cover, and the second box part 52 can also be called the lower box.

[0089] In battery 2, there are multiple battery cells 7. These multiple battery cells 7 can be connected in series, parallel, or in a mixed manner. A mixed connection means that multiple battery cells 7 are connected in both series and parallel. Multiple battery cells 7 can be directly connected in series, parallel, or in a mixed manner, and then the whole assembly of multiple battery cells 7 is housed in the housing 5. Alternatively, multiple battery cells 7 can first be connected in series, parallel, or in a mixed manner to form a battery module 6, and then multiple battery modules 6 can be connected in series, parallel, or in a mixed manner to form a whole assembly, which is then housed in the housing 5.

[0090] Figure 3 for Figure 2 A schematic diagram of the structure of battery module 6. (See diagram below.) Figure 3 As shown, in some embodiments, there are multiple battery cells 7, which 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 housed in a casing.

[0091] Please see Figures 4 to 6This application provides a battery cell 7, which includes a housing 71, an electrode assembly 72, and a support member 73. The electrode assembly 72 is disposed within the housing 71 and includes a positive electrode 721 and a negative electrode 722, which are stacked and wound to form a wound structure. The electrode assembly 72 includes a straight region R1 and a bent region R2, with the bent region R2 located at the end of the straight region R1 along a first direction X. The support member 73 is disposed within the housing 71, located on the side of the electrode assembly 72, and is used to reduce the expansion space of the innermost electrode 722a of the electrode assembly 72 located in the bent region R2 along the thickness direction Y of the electrode assembly 72.

[0092] In some embodiments of this application, the battery cell 7 may include a lithium-ion secondary battery cell 7, a lithium-ion primary battery cell, a lithium-sulfur battery cell, a sodium-lithium-ion battery cell, a sodium-ion battery cell, or a magnesium-ion battery cell, etc., and this application is not limited in this respect. The battery cell 7 may be flat, cuboid, or other shapes, and this application is not limited in this respect either. For ease of explanation, a flat battery shape is used as an example in the following embodiments. The battery cell 7 generally includes hard-shell battery cells and soft-pack battery cells, and this application is not limited in this respect either.

[0093] For some embodiments of this application, please refer to Figure 4 , Figure 4 This is an exploded view of a battery cell provided in some embodiments of this application. The battery cell 7 may include a housing 71, an electrode assembly 72, a support 73, an end cap 74, and an electrolyte.

[0094] The housing 71 may have an opening at one end or at both ends. The end cap 74 closes onto the opening of the housing 71 to form a space for accommodating the electrode assembly 72 and the electrolyte. Optionally, the housing 71 and the end cap 74 may be made of the same material, for example, both the housing 71 and the end cap 74 may be made of aluminum, which facilitates welding of the housing 71 and the end cap 74. Alternatively, the housing 71 and the end cap 74 may be made of different materials, for example, the housing 71 and the end cap 74 may be made of different metals, and other connection methods such as riveting may be used to connect the housing 71 and the end cap 74.

[0095] The electrode assembly 72 may include a positive electrode 721, a negative electrode 722, and a separator 723. The battery cell 7 mainly relies on the movement of metal ions between the positive electrode 721 and the negative electrode 722 to operate. The positive electrode 721, the negative electrode 722, and the separator 723 are stacked and then wound around a winding axis to form a wound structure.

[0096] Please see Figure 5 , Figure 5 for Figure 4 A schematic diagram of the cross-section of the electrode assembly in the XOY plane. The wound electrode assembly 72 includes a flat region R1 and a bent region R2 located at the end of the flat region R1 along the first direction X. The flat region R1 refers to the area with a parallel structure in the wound structure, that is, the positive electrode 721, negative electrode 722, and separator 723 within the flat region R1 are substantially parallel to each other, meaning that the surfaces of each layer of positive electrode 721, negative electrode 722, and separator 723 in the flat region R1 are planar. The bent region R2 refers to the area with a bent structure in the wound structure, that is, the positive electrode 721, negative electrode 722, and separator 723 within the bent region R2 are all bent, meaning that the surfaces of each layer of positive electrode 721, negative electrode 722, and separator 723 in the bent region R2 are curved. Figure 5 As shown, the straight region R1 has bending regions R2 at both ends along the first direction X.

[0097] The positive electrode 721 includes a positive current collector and a positive active material layer, the latter being coated on the surface of the current collector. Taking a lithium-ion battery as an example, the material of the current collector can be aluminum, and the positive active material layer includes the positive active material, which can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide, etc. The negative electrode 722 includes a negative current collector and a negative active material layer, the latter being coated on the surface of the current collector. The material of the current collector can be copper, and the negative active material layer includes the negative active material, which can be carbon or silicon, etc. The separator 723 can be made of PP or PE, etc.

[0098] Please see Figure 6 , Figure 6 for Figure 4 A schematic diagram of the fit between the electrode assembly and the support member. The support member 73 is located on the side of the electrode assembly 72, where the side of the electrode assembly 72 refers to the surface of the electrode assembly 72 on one side along its thickness direction Y. The shape of the support member 73 can be a prism, cylinder, elliptical cylinder, etc., and this embodiment is not limited thereto. The support member 73 can be made of insulating material to meet structural strength requirements such as resistance to collapse and compression, as well as high temperature resistance requirements for the materials used to prepare the battery. For example, porous polyolefin materials can be selected. In addition, electrolyte corrosion and electrochemical corrosion may occur within the battery cell 7, and the material of the support member 73 must also have acid and alkali resistance.

[0099] By providing a support member 73 on the side of the electrode assembly 72 inside the housing 71, the expansion space of the innermost electrode 722a of the electrode assembly 72 located in the bending region R2 along the thickness direction Y of the electrode assembly 72 can be reduced. During the charging and discharging process of the battery cell 7, the innermost electrode 722a of the electrode assembly 72 located in the bending region R2 is less likely to wrinkle, preventing lithium ions from depositing at the wrinkled area, which could lead to lithium plating triggering thermal runaway and improve the safety of the battery cell 7.

[0100] In some embodiments of this application, please refer to... Figure 6 At least a portion of the support member 73 is located at the boundary between the bending region R2 and the straight region R1. The boundary between the bending region R2 and the straight region R1 refers to the location near the intersection of the bending region R2 and the straight region R1 on the side of the electrode assembly 72, not the exact intersection point itself. Since the projection of the easily wrinkled portion of the innermost electrode 722a on the side of the electrode assembly 72 is located near this boundary, positioning the support member 73 at least partially at the boundary between the bending region R2 and the straight region R1 reduces the expansion space of the easily wrinkled portion of the innermost electrode 722a along the thickness direction Y of the electrode assembly 72. This makes the electrode less prone to wrinkling, preventing lithium ions from depositing at the wrinkled areas and causing lithium plating to trigger thermal runaway.

[0101] In some embodiments of this application, along the thickness direction Y, the largest dimension of the support member 73 corresponds to the corner of the innermost electrode 722a and abuts against the electrode assembly 72. The dimension of the support member 73 refers to its dimension along the thickness direction Y in the XOY plane. "Corresponds" means that... Figure 6 Within the cross-section shown, the projection of the support member 73 at its maximum size in the first direction X coincides or substantially coincides with the projection of the corner of the innermost electrode 722a in the first direction X. The corner of the innermost electrode 722a refers to the point where both sides of the electrode bend towards the center of the electrode assembly 72, such as... Figure 6 Points P1 and P2 are shown. The support 73 abutting against the electrode assembly 72 means that the support 73 is in contact with the electrode assembly 72. The support 73 and the electrode assembly 72 can have an interference fit, in which case there is an interaction force between them. Alternatively, the support 73 and the electrode assembly 72 can have a clearance fit, in which case there is no interaction force between them. Since the corner of the innermost electrode 722a of the electrode assembly 72 is prone to wrinkling, setting the largest dimension of the support 73 to correspond to the corner of the innermost electrode 722a, and having the support 73 abut against the electrode assembly 72, can reduce the expansion space along the thickness direction Y of the electrode assembly 72 at the corner of the innermost electrode 722a. This makes the electrode less prone to wrinkling, preventing lithium ions from depositing at the wrinkled area and causing lithium plating to trigger thermal runaway.

[0102] Please continue reading Figure 6 , Figure 6 The middle support 73 is a cuboid. The support 73 is positioned so that its length or width direction is consistent with its thickness direction Y. The dimensions of the support 73 along the thickness direction Y in the XOY plane are consistent everywhere. Any position of the support 73 along its length or width direction corresponds to the corner of the innermost electrode 722a and abuts against the electrode assembly 72.

[0103] Please see Figure 7 , Figure 7 This is a schematic diagram illustrating the fit between the electrode assembly and the support provided in some embodiments of this application. Figure 7 The middle support 73 is a cylinder. The largest dimension of the support 73 along the thickness direction Y in the XOY plane is P3. The P3 of the support 73 corresponds to the corner of the innermost electrode 722a and abuts against the electrode assembly 72.

[0104] In some embodiments of this application, along the second direction Z, the two ends of the support member 73 are flush with the ends of the negative electrode 722, and the second direction Z is perpendicular to both the first direction X and the thickness direction Y. In the electrode assembly 72, along the second direction Z, the ends of the negative electrode 722 extend beyond the ends of the positive electrode 721. Since the two ends of the support member 73 are flush with the ends of the negative electrode 722, that is, the height of the support member 73 is the same as the height of the negative electrode 722 and the position is the same in the second direction Z, the support member 73 can reduce the expansion space of the innermost electrode 722a of the electrode assembly 72 located in the bending region R2 along the thickness direction Y of the electrode assembly 72 in the second direction Z, and can also prevent the support member 73 from protruding from the negative electrode 722, increasing the weight of the battery cell 7 and reducing the energy density of the battery cell 7.

[0105] Furthermore, regarding the other dimensions of the support member 73, its thickness can be calculated based on the group margin of the electrode assembly thickness. The group margin refers to the ratio of the maximum dimension of the electrode assembly 72 to the maximum dimension of the housing 71 in the thickness direction Y.

[0106] Support thickness = (Shell inner cavity thickness - / Shell inner cavity thickness)

[0107] After the electrode assembly 72 and the support 73 are installed into the housing 71, the actual group degree at the corner of the innermost electrode 722a of the electrode assembly can meet or basically meet 100%.

[0108] For some embodiments of this application, please refer to Figures 8-9 ,in Figure 8 This is a schematic diagram of the structure of the support member provided in some embodiments of this application. Figure 9 for Figure 8The diagram shows the cooperation between the support member and the electrode assembly. The support member 73 includes a first support portion 731, a second support portion 732, and a connecting portion 733. The first support portion 731 and the second support portion 732 are located at opposite ends of the support member 73, and the connecting portion 733 connects the first support portion 731 and the second support portion 732. The bending region R2 includes a first bending region R. 21 Second bending area R 22 At least part of the first support portion 731 and the first bending area R 21 The positions correspond at least partially to the second support portion 732 and the second bending area R. 22 The positions correspond. "Correspond" means that at least a portion of the first support 731 corresponds to the first bending area R. 21 The projections in the first direction X have overlapping portions, and at least a portion of the second support 732 and the second bending region have overlapping portions in the projections in the first direction X. This is achieved by setting a portion that coincides with the first bending region R. 21 Second bending area R 22 The corresponding first support portion 731 and second support portion 732 can reduce the expansion space of the innermost electrode 722a at both ends along the thickness direction Y of the electrode assembly 72, making this part of the electrode less prone to wrinkling. By providing the connecting portion 733 between the first support portion 731 and the second support portion 732, the structural strength of the support member 73 can be improved.

[0109] In some embodiments of this application, please refer to... Figure 8 and Figure 9 The connecting portion 733 has a hollow structure to provide expansion space for the flat region R1. A hollow structure means that a portion of the connecting portion 733 is hollow, particularly the area corresponding to the middle part between the connecting portion 733 and the electrode assembly. During charging and discharging, lithium ions embedding into the electrode sheet causes changes in the electrode sheet's lattice parameters, resulting in expansion of the electrode sheet in the thickness direction Y, which expands and contracts with the frequency of charging and discharging. If the expansion of the electrode sheet in the flat region R1 in the thickness direction Y is suppressed, the electrolyte in the electrode assembly 72 will be squeezed out, affecting the transfer of lithium ions between the positive and negative electrodes, leading to large-area lithium plating, thermal runaway, and thus affecting the safety of the battery cell 7. By making the connecting portion 733 a hollow structure, expansion space can be reserved in the thickness direction Y for the flat region R1 of the electrode assembly 72, preventing lithium plating and reducing the impact on the safety of the battery cell 7.

[0110] Please continue reading Figure 8 and Figure 9 . Figure 8In the support member 73 shown, the connecting portion 733 includes a first connecting portion 733a and a second connecting portion 733b disposed along the thickness direction Y. The sides of the first connecting portion 733a and the second connecting portion 733b near the electrode assembly 72 are flush with the sides of the first support portion 731 and the second support portion 732 near the electrode assembly 72. Figure 9 As shown, the support member 73 is disposed between two electrode assemblies 72. The first connecting portion 733a and the second connecting portion 733b abut against the electrode assemblies 72 on both sides. The side of the first connecting portion 733a near the lower electrode assembly 72 is flush with the side of the first support portion 731 near the lower electrode assembly 72, and the side of the second connecting portion 733b near the upper electrode assembly 72 is flush with the side of the second support portion 732 near the upper electrode assembly 72. Both the first connecting portion 733a and the second connecting portion 733b are plate-shaped structures. By setting the first connecting portion 733a and the second connecting portion 733b along the thickness direction Y, a hollow structure is formed between the first connecting portion 733a and the second connecting portion 733b, which can reserve expansion space in the thickness direction Y for the flat area R1 of the electrode assembly 72, preventing lithium plating and thus reducing the impact on the safety of the battery cell 7. The sides of the first connecting portion 733a and the second connecting portion 733b near the electrode assembly 72 are flush with the sides of the first support portion 731 and the second support portion 732 near the electrode assembly 72, making the entire support member 73's side near the electrode assembly 72 planar. This reduces stress concentration at the contact points between the sides of the first support portion 731 and the second support portion 732 and the electrode assembly 72, thereby reducing damage to the electrode assembly 72 that it contacts, preventing positive and negative electrode plates from overlapping, and reducing the risk of internal short circuits in the battery cell 7.

[0111] Please continue reading Figure 8 . Figure 8 In the support member 73 shown in the figure, the connecting part 733 includes a first connecting part 733a and a second connecting part 733b arranged along the second direction Z. A hollow structure is formed between the first connecting part 733a and the second connecting part 733b. The second direction Z is perpendicular to the first direction X and the thickness direction Y. Figure 8 The first connecting part 733a and the second connecting part 733b shown are X-shaped brackets. Figure 8 The first connecting portion 733a and the second connecting portion 733b shown are thin plate-shaped supports. Those skilled in the art should understand that the first connecting portion 733a and the second connecting portion 733b can also be other shapes, and the present invention does not limit them. The first connecting portion 733a and the second connecting portion 733b arranged along the second direction Z can improve the structural strength of the support member 73 and prevent the support frame from collapsing.

[0112] The shapes of the first support portion 731 and the second support portion 732 can be prisms, cylinders, elliptical cylinders, etc., and the embodiments of this application are not limited to this. Figure 8 The first support portion 731 and the second support portion 732 shown are cuboid structures, and their cross-sectional shapes in the XOY plane are rectangular. The cuboid structure of the first support portion 731 and the second support portion 732 is easy to process. Moreover, when there is an interaction force between the electrode assembly 72 and the support member 73, the cuboid structure of the first support portion 731 and the second support portion 732 has sufficient strength to abut against the electrode assembly 72, reducing the probability of expansion of the innermost electrode sheet 722a of the electrode assembly 72 located in the bending region R2 along the thickness direction Y of the electrode assembly 72, and reducing the risk of wrinkling of the innermost electrode sheet 722a of the electrode assembly 72 located in the bending region R2.

[0113] For some embodiments of this application, please refer to Figures 10-11 ,in Figure 10 This is a schematic diagram of the structure of the support member provided in some embodiments of this application. Figure 11 for Figure 10 The diagram shows the cooperation between the support and the electrode assembly. Figure 10 The structure of the first support part 731 and the second support part 732 Figure 8 Unlike the previous one, the first support part 731 and the second support part 732 are a combination of two triangular prisms in the XOY plane. The cross-sectional shape of the two support parts 731 and 732 is a combination of two triangles. The two triangles are set opposite each other, with their vertices connected and their bases parallel. Figure 10 The structure of the middle connecting part 733 and Figure 8 The components are the same or substantially the same. Compared to a cuboid structure with the same cross-sectional side length, the combination structure of two triangular prisms can reduce the material used in the support component 73, lighten its weight, and increase the energy density of the battery cell 7.

[0114] In some embodiments of this application, the outer surface of the support 73 that contacts the electrode assembly 72 is an arc surface. Please refer to... Figures 12-13 ,in Figure 12 This is a schematic diagram of the structure of the support member provided in some embodiments of this application. Figure 13 for Figure 12 The diagram shows the cooperation between the support and the electrode assembly. Figure 12 The structure of the first support part 731 and the second support part 732 Figure 8 as well as Figure 10 Unlike other parts, the first support part 731 and the second support part 732 are cylindrical, and their cross-sectional shapes in the XOY plane are circular. Figure 12 The structure of the middle connecting part 733 and Figure 8The components are the same or substantially the same. The first support portion 731 and the second support portion 732 of the cylinder make the outer surface of the support member 73 in contact with the electrode assembly 72 an arc surface. Compared with the support member 73 with sharp edges on the sides, this can further reduce the stress concentration at the contact position between the sides of the first support portion 731 and the second support portion 732 and the electrode assembly 72, thereby avoiding damage to the electrode assembly 72 in contact with the support portion, preventing the positive and negative electrode plates from overlapping, and reducing the risk of internal short circuit in the battery cell 7.

[0115] In some embodiments described above, the connecting part 733 can be integrally formed with the first support part 731 and the second support part 732, or these parts can be processed separately and then assembled into a support member 73. For example, the first support part 731, the second support part 732 and the connecting part 733 can be fixed together by welding, screwing, gluing or other methods to obtain the support member 73.

[0116] In some embodiments of this application, please refer to... Figure 4 and Figure 6 The battery cell 7 contains one electrode assembly 72 and one support member 73. In the thickness direction Y, the support member 73 is disposed between the housing 71 and the electrode assembly 72.

[0117] For some embodiments of this application, please refer to Figure 14 , Figure 14 This is a schematic diagram illustrating the fit between the electrode assembly and the support member in a battery cell according to some embodiments of this application. The battery cell 7 contains one electrode assembly 72 and two sets of support members 73, each set including two support members. In the thickness direction Y, the two sets of support members 73 are respectively disposed on both sides of the electrode assembly 72, located between the housing 71 and the electrode assembly 72. The thickness of a single support member 73 can be... Figure 6 The thickness of the middle support component is half that of 73.

[0118] In some embodiments of this application, the battery cell 7 includes a plurality of electrode assemblies 72, which are arranged side-by-side along the thickness direction Y within a housing 71. A support member 73 is disposed between the housing 71 and the electrode assemblies 72 adjacent to the housing 71 in the thickness direction Y. See also... Figure 15 , Figure 15 This is a schematic diagram illustrating the fit between electrode assemblies and support members in a battery cell according to some embodiments of this application. The battery cell 7 includes two electrode assemblies 72, which are arranged side-by-side along the thickness direction Y within a housing 71. A support member 73 is disposed between the housing 71 and the electrode assemblies 72 adjacent to the housing 71 in the thickness direction Y.

[0119] Please see Figure 16 , Figure 16This is a schematic diagram illustrating the fit between electrode assemblies and supports in a battery cell according to some embodiments of this application. The battery cell 7 includes four electrode assemblies 72, which are arranged side-by-side along the thickness direction Y within a housing 71. A support 73 is disposed between the housing 71 and the electrode assemblies 72 adjacent to the housing 71 in the thickness direction Y. In some embodiments of this application, the battery cell 7 includes multiple electrode assemblies 72, which are arranged side-by-side along the thickness direction Y within a housing 71, and a support 73 is disposed between two adjacent electrode assemblies 72.

[0120] Please see Figure 17 , Figure 17 This is a schematic diagram illustrating the fit between electrode assemblies and support members in a battery cell according to some embodiments of this application. The battery cell 7 includes two electrode assemblies 72, which are arranged side-by-side along the thickness direction Y within a housing 71. A support member 73 is disposed between two adjacent electrode assemblies 72 along the thickness direction Y.

[0121] Please see Figure 18 , Figure 18 This is a schematic diagram illustrating the cooperation between electrode assemblies and support members in a battery cell according to some embodiments of this application. The battery cell 7 includes four electrode assemblies 72, which are arranged side-by-side along the thickness direction Y within a housing 71. Support members 73 are disposed between adjacent electrode assemblies 72 along the thickness direction Y.

[0122] Please see 19. Figure 19 This is a schematic diagram illustrating the cooperation between electrode assemblies and support members in a battery cell according to some embodiments of this application. The battery cell 7 includes four electrode assemblies 72, which are arranged side-by-side along the thickness direction Y within a housing 71. Support members 73 are disposed between adjacent electrode assemblies 72 along the thickness direction Y.

[0123] By placing the support 73 between two adjacent electrode assemblies 72 in a plurality of electrode assemblies 72, one support 73 can simultaneously prevent the innermost electrode 722a of the two electrode assemblies 73 located on both sides of it from wrinkling, thereby achieving the same effect by using fewer support 73 and reducing the weight of the battery cell 7.

[0124] For some embodiments of this application, please refer to Figures 20-23 , Figure 20 This is an exploded view of a single battery cell provided in some embodiments of this application. Figure 21 for Figure 20 Assembly diagram of the fastener and electrode assembly. Figure 22 for Figure 21 A top view of the fastener and electrode assembly in the XOY plane. Figure 23 for Figure 22 A schematic diagram of the cross-sectional structure along the AA direction is shown. In the figure, the support member 73 is fixed to the side of the electrode assembly 72 by a snap fastener 734. By setting the snap fastener 734, the support member 73 can be fixed to the side of the electrode assembly 72, preventing the support member 73 from collapsing or shifting relative to the electrode assembly 72 during use, which would reduce the suppression effect on wrinkling of the innermost electrode sheet 722a of the electrode assembly 72 located in the bending region R2. If the support member 73 collapses or shifts relative to the electrode assembly 72, the position of the support frame will not correspond to the innermost electrode sheet 722a of the electrode assembly 72 located in the bending region R2, thus failing to reduce the expansion space of the innermost electrode sheet 722a of the electrode assembly 72 located in the bending region R2 along the thickness direction Y of the electrode assembly 72. Moreover, the fixing method of the snap fastener 734 improves the structural strength of the support member 73.

[0125] Figures 20-23 In the illustrated embodiment, the latching member 734 includes a latching plate disposed at the top of the support member 73, which overlaps the top of the electrode assembly 72; and a latching plate disposed at the bottom of the support member 73, which overlaps the bottom of the electrode assembly 72. The latching member 734 may only overlap the electrode assembly 72, and the positional cooperation between the electrode assembly 72, the support member 73, and the latching member 734 limits the support member 73, thereby fixing the support member 73 to the side of the electrode assembly 72. Those skilled in the art should understand that in other embodiments, the latching member 734 may also be fixed to the electrode assembly 72 by a fastener, making the fixation between the support member 73 and the electrode assembly 72 more secure. The battery cell 7 shown in the figure includes two electrode assemblies 72, and the support member 73 is disposed between the electrode assemblies 72, so the latching member 734 overlaps the electrode assemblies 72 on both sides of the support member 73. In some embodiments, the battery cell 7 includes only one electrode assembly 72, and the support member 73 is disposed between the electrode assembly 72 and the housing 71. Alternatively, although the battery cell 7 includes multiple electrode assemblies 72, the support member 73 is also disposed between the electrode assembly 72 and the housing 71. In this case, the fastener 734 can only be attached to the electrode assembly 72 on one side of the support member 73.

[0126] Those skilled in the art will understand that a latching member 734 can be provided only at one end of the support member 73. For example, in some embodiments, the latching member 734 includes a latching plate disposed at the top of the support member 73, which overlaps the top of the electrode assembly 72. The positional cooperation between the electrode assembly 72, the support member 73, and the latching member 734 limits the support member 73, thereby fixing the support member 73 to the side of the electrode assembly 72. Having a latching member 734 only at one end of the support member 73 facilitates assembly, reduces the weight of the battery cell 7, and increases the energy density of the battery cell 7.

[0127] In the above embodiments, the fastener 734 can be an independent component or it can be integrally formed with the support 73.

[0128] For some embodiments of this application, please refer to Figure 24 , Figure 24 This is an exploded view of a battery cell provided in some embodiments of this application. The support member 73 is fixed to the side of the electrode assembly 72 by adhesive bonding, and S is the bonding surface on the support member. By fixing the support member 73 to the side of the electrode assembly 72, it prevents the support member 73 from collapsing or shifting relative to the electrode assembly 72 during use. If the support member 73 collapses or shifts relative to the electrode assembly 72, the position of the support frame will not correspond to the innermost electrode 722a of the electrode assembly 72 located in the bending region R2, thus failing to reduce the expansion space of the innermost electrode 722a of the electrode assembly 72 located in the bending region R2 along the thickness direction Y of the electrode assembly 72. Moreover, the bonding method can reduce the weight of the sandwich unit and has a smaller impact on the energy density of the battery cell 7.

[0129] The surface of the support member 73 can have appropriate adhesiveness, so that the support member 73 can be well adhered and fixed to the side of the electrode assembly 72. Those skilled in the art should understand that an adhesive support member 73 can be selected, or a non-adhesive support member 73 can be selected, and an adhesive or backing can be applied to the side of its surface that abuts against the electrode assembly 72, or an adhesive or backing can be applied to the surface of the electrode assembly 72 that abuts against the support member 73, so as to facilitate the adhesion of the support member 73.

[0130] In some embodiments of this application, the support member 73 is provided with a through hole for electrolyte to pass through in the second direction Z, and the second direction Z is perpendicular to both the first direction X and the thickness direction Y. The formation of the through hole is not limited; it can be formed by opening a through hole in the support member 73, or by selecting a material with inherent through holes to make the support member 73, such as a porous polyolefin material with a certain surface porosity. Because the support member 73 is provided with a through hole for electrolyte to pass through in the second direction Z, the electrolyte can flow from the bottom to the top of the battery cell 7 through this through hole, improving the wetting effect of the electrolyte on the electrode assembly 72 and ensuring the charge and discharge performance of the battery cell 7.

[0131] For some embodiments of this application, please refer to Figure 25 , Figure 25The diagram shows an exploded view of a battery cell according to some embodiments of this application. The electrode assembly 72 further includes a separator for isolating the positive and negative electrode plates. The support is one or more layers of separator 723 located on the outside of the electrode assembly 72. The one or more layers of separator 723 have through holes 724 extending along the thickness direction Y, and the through holes 724 are provided corresponding to the flat region R1. One or more layers of separator 723 are wound around the outside of the electrode assembly 72 as a support to reduce the expansion space of the innermost electrode 722a of the electrode assembly 72 located in the bending region R2 along the thickness direction Y of the electrode assembly 72. In addition, during the charging and discharging process of the battery cell 7, the embedding of lithium ions into the electrode plate will cause changes in the lattice parameters of the electrode plate, causing the electrode plate to expand in the thickness direction Y, and expanding and contracting with the frequency of charging and discharging. If the expansion of the electrode plate in the flat region R1 in the thickness direction Y is suppressed, the electrolyte in the electrode assembly 72 will be squeezed out, affecting the transfer of lithium ions between the positive and negative electrodes, resulting in large-area lithium plating, causing thermal runaway, and thus affecting the safety of the battery cell 7. By creating through holes 724 in the separator 723, which serves as a support, expansion space can be reserved in the thickness direction Y for the flat region R1 of the electrode assembly 72, preventing lithium plating and thus reducing the impact on the safety of the battery cell 7. Furthermore, directly using the separator as a support simplifies the components and reduces processing and assembly difficulties.

[0132] The number of layers of the diaphragm 723 serving as the support 73 can be calculated based on the group degree of the electrode assembly 72 thickness. For example, if the group degree at the corner of the innermost electrode 722a is 90%, then:

[0133] Number of membrane layers = () / thickness of a single membrane layer

[0134] After the wound electrode assembly 72 is installed into the housing 71, the actual group density at the corner of the innermost electrode 722a of the electrode assembly 72 meets or nearly meets 100%. If the group density exceeds 100%, it exceeds the thickness of the housing 71 that can accommodate the electrode assembly 72, and the electrode assembly 72 cannot be installed into the housing 71, or forcibly installing the electrode assembly 72 into the housing 71 will damage the electrode assembly 72. If the group density is less than 100%, the one or more layers of diaphragms 723 located on the outside of the electrode assembly 72, which serve as support members 73, cannot effectively reduce the expansion space of the innermost electrode 722a of the electrode assembly 72 located in the bending region R2 along the thickness direction Y of the electrode assembly 72.

[0135] The size of the through hole 724 in the diaphragm 723, which serves as the support member 73, is determined based on the overall size of the electrode assembly 72 and the size of the bending region R2. For example, if the width of the electrode assembly 72 is X1, the height is Y1, and the width at the corner of the bending region R2 is X2, then the size of the through hole 724 is:

[0136] Through hole width = X1 - X2 * 2

[0137] Through hole height = Y1-2k, where k is determined according to processing requirements, and k refers to the distance between the through hole 724 and the edge of the diaphragm 723 in the second direction Z.

[0138] Please see Figure 26 , Figure 26 This is a schematic flowchart illustrating a method for preparing a battery cell according to some embodiments of this application. The method for preparing a battery cell includes the following:

[0139] Step 261, provide the housing.

[0140] Step 262, providing an electrode assembly, the electrode assembly including a positive electrode sheet and a negative electrode sheet, the positive electrode sheet and the negative electrode sheet being stacked and wound to form a wound structure, the electrode assembly including a straight region and a bent region, the bent region being located at the end of the straight region along a first direction.

[0141] Step 263, provide support components.

[0142] Step 264: The electrode assembly and the support are placed inside the housing, and the support is located on the side of the electrode assembly so that the support can reduce the expansion space of the innermost electrode sheet of the electrode assembly located in the bending area along the thickness direction of the electrode assembly.

[0143] The relevant structure of the battery cell manufactured by the method in this embodiment can be referred to the foregoing. Figure 1-25 The details of the battery cell 7 described in the corresponding embodiments will not be repeated here.

[0144] Please see Figure 27 , Figure 27 This is a schematic diagram of the structure of an apparatus for preparing battery cells according to some embodiments of this application. The apparatus 8 for preparing battery cells includes: a first providing device 81, a second providing device 82, a third providing device 83, and an assembly device 84.

[0145] The first providing device 81 is configured to provide a housing.

[0146] The second providing device 82 is configured to provide an electrode assembly, the electrode assembly including a positive electrode and a negative electrode, the positive electrode and the negative electrode being stacked and wound to form a wound structure, the electrode assembly including a straight region and a bent region, the bent region being located at the end of the straight region along a first direction.

[0147] The third providing device 83 is configured to provide a support member.

[0148] Assembly device 84 is configured to house the electrode assembly and support within the housing, with the support positioned on the side of the electrode assembly, so that the support can reduce the expansion space of the innermost electrode sheet of the electrode assembly located in the bending region along the thickness direction of the electrode assembly.

[0149] The relevant structure of the battery cell manufactured using the equipment in this embodiment can be referred to the foregoing. Figure 1-25 The details of the battery cell 7 described in the corresponding embodiments will not be repeated here.

[0150] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A battery cell, characterized by, The battery cell comprises: a shell; an electrode assembly arranged in the shell, the electrode assembly comprising a positive electrode tab and a negative electrode tab, the positive electrode tab and the negative electrode tab being laminated and wound to form a winding structure, the electrode assembly comprising a flat area and a bending area, the bending area being located at an end of the flat area along a first direction; a support provided in the shell and located at a side of the electrode assembly, the support being used to reduce the expansion space of the innermost layer of the electrode tab of the electrode assembly located at the bending area along the thickness direction of the electrode assembly, at least part of the support being located at the junction of the bending area and the flat area.

2. The battery cell of claim 1, wherein, Along the thickness direction, the largest dimension of the support corresponds to the corner of the innermost layer of the electrode tab and abuts against the electrode assembly.

3. The battery cell of claim 1, wherein, Along a second direction, both ends of the support are flush with the end of the negative electrode tab, the second direction being perpendicular to both the first direction and the thickness direction.

4. The battery cell of claim 1, wherein, The support comprises a first support part, a second support part and a connecting part, the first support part and the second support part being located at both ends of the support respectively, and the connecting part being used to connect the first support part and the second support part; The bending area comprises a first bending area and a second bending area, at least part of the first support part corresponding to the position of the first bending area, and at least part of the second support part corresponding to the position of the second bending area.

5. The battery cell of claim 4, wherein the cathode comprises a lithium metal oxide. The connecting part is a hollow structure and is used to provide expansion space for the flat area.

6. The battery cell of claim 5, wherein, The connecting part comprises a first connecting part and a second connecting part arranged along a second direction, the hollow structure being formed between the first connecting part and the second connecting part, the second direction being perpendicular to both the first direction and the thickness direction.

7. The battery cell of claim 5, wherein the cathode comprises a lithium metal oxide. The connecting part comprises a first connecting part and a second connecting part arranged along the thickness direction, the first connecting part and the second connecting part being flush with the first support part and the second support part close to the side of the electrode assembly.

8. The battery cell of any one of claims 1-7, wherein, The outer surface of the support in contact with the electrode assembly is an arc surface.

9. The battery cell of any one of claims 1-7, wherein, The battery cell comprises a plurality of electrode assemblies arranged side by side in the shell along the thickness direction, and the support is arranged between the shell and the electrode assembly adjacent to the shell along the thickness direction.

10. The battery cell of any one of claims 1-7, wherein, The battery cell comprises a plurality of electrode assemblies arranged side by side in the shell along the thickness direction, and the support is arranged between two adjacent electrode assemblies.

11. The battery cell of any one of claims 1-7, wherein, The support is fixed to the side of the electrode assembly by pasting, or the support is fixed to the side of the electrode assembly by a buckle.

12. The battery cell of any one of claims 1-7, wherein, The support is provided with a through hole for electrolyte to pass through along a second direction, the second direction being perpendicular to both the first direction and the thickness direction.

13. The battery cell of any one of claims 1-2, wherein, The electrode assembly further comprises a separator for isolating the positive electrode tab and the negative electrode tab, the support being one or more separators located outside the electrode assembly, the one or more separators having a through hole along the thickness direction, the through hole being provided corresponding to the flat area.

14. A battery, characterized by The battery cell comprises: The battery cell according to any one of claims 1-13.

15. An electrical device, comprising: The power consuming device includes the battery cell according to any one of claims 1-13, and the battery cell is configured to provide electric energy.

16. A method of making a battery cell, characterized by, Providing a housing; Providing an electrode assembly including a positive electrode tab and a negative electrode tab, the positive electrode tab and the negative electrode tab being stacked and wound to form a wound structure, the electrode assembly including a flat area and a bent area, the bent area being located at an end of the flat area in a first direction; Providing a support member; Providing the electrode assembly and the support member in the housing, and locating the support member at a side of the electrode assembly, so that the support member can reduce an expansion space of an innermost layer tab of the electrode assembly located at the bent area in a thickness direction of the electrode assembly, at least part of the support member being located at an interface between the bent area and the flat area. Providing a housing; 17. An apparatus for preparing a battery cell, characterized by Providing an electrode assembly including a positive electrode tab and a negative electrode tab, the positive electrode tab and the negative electrode tab being stacked and wound to form a wound structure, the electrode assembly including a flat area and a bent area, the bent area being located at an end of the flat area in a first direction; Providing a support member; Providing the electrode assembly and the support member in the housing, and locating the support member at a side of the electrode assembly, so that the support member can reduce an expansion space of an innermost layer tab of the electrode assembly located at the bent area in a thickness direction of the electrode assembly, at least part of the support member being located at an interface between the bent area and the flat area. ​ ​

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