Electrode assembly and manufacturing method therefor, battery cell, battery, and electrical device

Abstract

An electrode assembly (30) and a manufacturing method therefor, a battery cell (7), a battery, and an electrical device, said electrode assembly (30) comprising a first electrode plate (301) and a second electrode plate (302) that have opposite polarities, as well as a first insulator (303). The first electrode plate (301) and the second electrode plate (302) are wound in a winding direction. The first electrode plate (301) comprises a first current collector (3011) and a first active material layer (3012) arranged on a surface of the first current collector (3011). An end portion of the first current collector (3011) in the winding direction is provided with a first end face (30111). The first insulator (303) is connected to the first electrode plate (301) and covers at least part of the first end face (30111). In the described structure, the first end face (30111) provided at the end portion of the first current collector (3011) is covered with the first insulator (303), and the first insulator (303) can wrap up burrs on the first end face (30111). Thus, the risk of burrs piercing a separator (305) of the electrode assembly (30) is reduced, the possibility of short circuiting occurring inside of the battery is reduced, and improvement to the reliability of the battery is facilitated.

Description

Electrode assembly and manufacturing method thereof, battery cell, battery and electrical device

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to Chinese patent application No. 202410160635.1 filed on February 4, 2024, entitled “Electrode assembly and method for manufacturing the same, battery cell, battery and electrical device,” the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present application relates to the field of battery technology, and in particular to an electrode assembly and a manufacturing method thereof, a battery cell, a battery, and an electrical device. Background Art

[0004] Batteries have the advantages of high specific energy and high power density. They are widely used in electronic devices and transportation vehicles, such as mobile phones, laptops, electric vehicles, electric airplanes, electric ships, and electric tools.

[0005] As the application scope of batteries continues to expand, people's requirements for battery reliability are also getting higher and higher. How to improve battery reliability has attracted more and more attention from those skilled in the art.

[0006] Summary of the Invention

[0007] In view of the above problems, the present application provides an electrode assembly and a manufacturing method thereof, a battery cell, a battery and an electrical device. The electrode assembly is conducive to improving the reliability of the battery.

[0008] In a first aspect, the present application provides an electrode assembly, comprising a first electrode sheet and a second electrode sheet of opposite polarity, the first electrode sheet and the second electrode sheet being wound along a winding direction; the first electrode sheet comprising a first current collector and a first active material layer disposed on a surface of the first current collector, the end of the first current collector along the winding direction having a first end face; the electrode assembly further comprising a first insulating member connected to the first electrode sheet and covering at least a portion of the first end face. In the above structure, since the first end face of the end of the first current collector is covered with the first insulating member, the first insulating member can cover burrs at the first end face, thereby reducing the risk of burrs piercing the separator of the electrode assembly, reducing the possibility of a short circuit within the battery, and facilitating improved battery reliability.

[0009] According to the electrode assembly provided in some embodiments of the present application, a first insulating member is provided at both ends of the first pole piece along the winding direction, so that the burrs on the first end faces at both ends of the first pole piece can be covered, which can further reduce the risk of the burrs piercing the isolation member of the electrode assembly, and is conducive to further improving the reliability of the battery.

[0010] According to the electrode assembly provided in some embodiments of the present application, the first insulating member is bonded to the first active material layer or the first current collector, so that the first insulating member is firmly connected to the first electrode sheet and is not easy to fall off.

[0011] According to the electrode assembly provided in some embodiments of the present application, the first insulating member includes two oppositely arranged first insulating layers, the first insulating layer includes a first connecting portion and a first covering portion, the first covering portion is stacked on the first pole piece, and the first connecting portions of the two first insulating layers are bonded to each other to achieve the covering of the first end face between the two opposite surfaces connected to the first pole piece.

[0012] According to the electrode assembly provided in some embodiments of the present application, the thickness of the first electrode piece is H1, the thickness of the first insulating layer is H2, This is beneficial to reducing the occurrence of steps in the electrode assembly formed by winding, and reduces the possibility of cracks in the first pole piece due to step stress.

[0013] According to the electrode assembly provided in some embodiments of the present application, the inner end of the first pole piece is connected to the first insulating member, and at least a portion of the first pole piece is wound around the outside of the first insulating member, so that the first insulating member at the inner end of the first pole piece can be wound around the center of the electrode assembly, so that the first insulating member can support the electrode assembly, which is beneficial to reduce the possibility of collapse of the electrode assembly.

[0014] According to the electrode assembly provided in some embodiments of the present application, in the direction opposite to the winding direction, the length of the first insulating member at the inner end of the first pole piece extending out of the first pole piece is A1, and 0.5mm≤A1≤120mm.

[0015] According to the electrode assembly provided in some embodiments of the present application, the second pole piece includes a second current collector and a second active material layer arranged on the surface of the second current collector, and the end of the second current collector along the winding direction has a second end face; the electrode assembly also includes a second insulating member, which is connected to the second pole piece and covers at least a portion of the second end face, so that the burrs on the part of the second end face covered by the second insulating member are covered by the second insulating member, reducing the possibility of the burrs piercing the isolation member and reducing the risk of short circuit in the battery cell.

[0016] According to the electrode assembly provided in some embodiments of the present application, the elastic modulus of the first insulating member is greater than the elastic modulus of the first pole piece, and the elastic modulus of the second insulating member is greater than the elastic modulus of the second pole piece, so that the first insulating member connected to the inner end of the first pole piece can better support the center of the electrode assembly, and the second insulating member connected to the inner end of the second pole piece can better support the center of the electrode assembly, which is beneficial to reducing the possibility of collapse of the electrode assembly.

[0017] According to the electrode assembly provided in some embodiments of the present application, the first electrode piece is an anode electrode piece, and the second electrode piece is a cathode electrode piece. In the opposite direction of the winding direction, the first insulating member extends from the second insulating member, so that the first insulating member connected to the anode electrode piece can be longer than the second insulating member at the center of the electrode assembly and wound into the center of the electrode assembly.

[0018] According to the electrode assembly provided in some embodiments of the present application, in the thickness direction of the first pole piece, the thickness of the first insulating member is H3, and the thickness of the second insulating member is F3, H3>F3, so that the first insulating member at the inner end of the first pole piece wound in the center of the electrode assembly can provide greater supporting force, which is beneficial to improving the effect of reducing collapse.

[0019] According to the electrode assembly provided in some embodiments of the present application, in the opposite direction of the winding direction, the first insulating member is located on the inner side of the second insulating member, so that the first insulating member as a whole is located on the inner side of the second insulating member, which not only enables the anode electrode sheet to extend beyond the cathode electrode sheet in the winding direction, but also enables the first insulating member connected to the inner end of the first electrode sheet to be better wound in the center of the electrode assembly, thereby better playing a supporting role.

[0020] According to the electrode assembly provided in some embodiments of the present application, the elastic modulus of the first insulating member is greater than the elastic modulus of the second insulating member, so that the first insulating member connected to the inner end of the first pole piece can provide a greater elastic restoring force to support the center of the electrode assembly after winding, so that the first insulating member can better reduce the possibility of collapse of the electrode assembly.

[0021] According to the electrode assembly provided in some embodiments of the present application, a second insulating member is provided at both ends of the second pole piece along the winding direction, so that the burrs on the second end faces at both ends of the second pole piece can be covered, which can further reduce the risk of the burrs piercing the isolation member of the electrode assembly, and is conducive to further improving the reliability of the battery.

[0022] According to the electrode assembly provided in some embodiments of the present application, the length of the second insulating member at the inner end of the second pole piece extending from the second pole piece is B1, and the length of the second insulating member at the outer end of the second pole piece extending from the second pole piece is B4, B1>B4, which can enable the second insulating member to have a good supporting effect while reducing waste.

[0023] According to the electrode assembly provided in some embodiments of the present application, the electrode assembly has a cylindrical structure.

[0024] According to the electrode assembly provided in some embodiments of the present application, the first pole piece also includes a first pole ear connected to the first current collector, and the first pole ear includes a flattened area. The flattened area is spaced apart from the first insulating member so that the flattened area and the first insulating member are separated, so that the first insulating member will not affect the connection between the flattened area and the current collecting plate.

[0025] In a second aspect, the present application provides a battery cell, which includes a housing and at least one electrode assembly provided by any of the above technical solutions, housed in the housing.

[0026] In a third aspect, the present application provides a battery comprising the battery cell provided by the above technical solution.

[0027] In a fourth aspect, the present application provides an electrical device, which includes a battery provided by the above technical solution, and the battery is used to provide electrical energy.

[0028] In a fifth aspect, the present application provides a method for manufacturing an electrode assembly, the method comprising the following steps:

[0029] Providing a plurality of first pole pieces and insulating members, wherein the first pole piece includes a first current collector and a first active material layer disposed on a surface of the first current collector, and the first current collector has a first end surface at an end portion along its length direction;

[0030] connecting two adjacent first pole pieces via an insulating member, wherein the insulating member covers at least a portion of the first end surface;

[0031] Winding the first pole piece and the insulating member in the length direction of the first current collector;

[0032] The insulating member between two adjacent first pole pieces is cut to form first insulating members at both ends of the first pole piece in the winding direction, and the first insulating member covers at least a portion of the first end surface.

[0033] The technical solutions provided by the embodiments of the present disclosure bring at least the following beneficial effects:

[0034] The present application provides an electrode assembly, which includes a first electrode sheet and a second electrode sheet of opposite polarity and a first insulating member. The first electrode sheet and the second electrode sheet are wound along a winding direction. The first electrode sheet includes a first current collector and a first active material layer disposed on the surface of the first current collector. The end of the first current collector along the winding direction has a first end face. The first insulating member is connected to the first electrode sheet and covers at least a portion of the first end face. In the above structure, because the first end face of the end of the first current collector is covered with the first insulating member, the first insulating member can cover the burrs at the first end face, reducing the risk of the burrs piercing the insulating member of the electrode assembly, reducing the possibility of a short circuit inside the battery, and helping to improve the reliability of the battery.

[0035] 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

[0036] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiment below. The accompanying drawings are for illustration purposes only and are not to be considered as limiting the present application. Throughout the accompanying drawings, the same reference numerals are used to denote the same components.

[0037] FIG1 is a schematic structural diagram of a vehicle provided in some embodiments of the present application;

[0038] FIG2 is a disassembled diagram of a battery provided in some embodiments of the present application;

[0039] FIG3 is an exploded view of a battery module provided in some embodiments of the present application;

[0040] FIG4 is a cross-sectional view of a battery cell provided in some embodiments of the present application;

[0041] FIG5 is a cross-sectional view of an electrode assembly in a battery cell provided in some embodiments of the present application;

[0042] FIG6 is a cross-sectional view of a first pole piece provided in some embodiments of the present application;

[0043] FIG7 is a cross-sectional view of a first insulating member and a first pole piece connected together according to some embodiments of the present application;

[0044] FIG8 is a cross-sectional view of a second pole piece provided in some embodiments of the present application;

[0045] FIG9 is a cross-sectional view of a second insulating member and a second pole piece connected together according to some embodiments of the present application;

[0046] FIG10 is a top view of a first end surface of a first pole piece provided in some embodiments of the present application;

[0047] FIG11 is a top view of the first end surface of the first pole piece provided in some other embodiments of the present application.

[0048] In the attached figure: 1. Vehicle; 2. Battery; 3. Controller; 4. Motor; 5. Housing; 5a. First housing portion; 5b. Second housing portion; 5c. Accommodation space; 6. Battery module; 7. Battery cell; 20. Housing; 30. Electrode assembly; 301. First pole piece; 3011. First current collector; 30111. First end face; 3012. First active material layer; 3013. First pole tab; 30131. Flattening area; 302. Second pole piece; 3021. Second current collector; 30211. Second end face; 3022. Second active material layer; 303. First insulating member; 3031. First insulating layer; 30311. First connecting portion; 30312. First covering portion; 304. Second insulating member; 3041. Second insulating layer; 30411. Second connecting portion; 30412. Second covering portion; 305. Isolator; X, winding direction. DETAILED DESCRIPTION

[0049] The following embodiments of the technical solution of the present application will be described in detail with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application and are therefore only examples and are not intended to limit the scope of protection of the present application.

[0050] It should be noted that, unless otherwise specified, the technical terms or scientific terms used in the embodiments of the present application should have the common meanings understood by technicians in the field to which the embodiments of the present application belong.

[0051] In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they should not be understood as limiting the embodiments of the present application.

[0052] In addition, the technical terms "first," "second," etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. In the description of the embodiments of the present application, the meaning of "plurality" is two or more (including two), unless otherwise clearly and specifically defined.

[0053] In the description of the embodiments of the present application, unless otherwise expressly specified or limited, technical terms such as "installed," "connected," "connected," and "fixed" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal connections between two components or interactions between two components. Those skilled in the art can understand the specific meanings of the above terms in the embodiments of the present application based on specific circumstances.

[0054] In the description of the embodiments of the present application, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Furthermore, a first feature being "above," "above," and "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is at a higher level than the second feature. A first feature being "below," "below," and "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0055] Currently, judging by market developments, batteries are becoming increasingly widely used. They are not only used in energy storage systems such as hydropower, thermal power, wind power, and solar power stations, but are also widely used in electric vehicles such as electric bicycles, electric motorcycles, and electric cars.

[0056] The battery mentioned in the embodiments of the present application refers to a single physical module including one or more battery cells to provide higher voltage and capacity.

[0057] In the embodiment of the present application, the battery cell may be a secondary battery. A secondary battery refers to a battery cell that can be continuously used by activating active materials by charging after the battery cell is discharged.

[0058] Battery cells may include but are not limited to 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.

[0059] As an example, the battery cell may be a cylindrical battery cell, a prismatic battery cell or a battery cell of other shapes. Prismatic battery cells include square-shell battery cells, blade-shaped battery cells, and polygonal prismatic batteries. Polygonal prismatic batteries are, for example, hexagonal prismatic batteries.

[0060] In some embodiments, the battery may be a battery module. When there are multiple battery cells, the multiple battery cells are arranged and fixed to form a battery module.

[0061] In some embodiments, the battery may be a battery pack, which includes a case and battery cells, wherein the battery cells or battery modules are housed in the case.

[0062] 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.

[0063] In some embodiments, the battery may be an energy storage device, including an energy storage container, an energy storage cabinet, and the like.

[0064] A battery cell typically consists of an electrode assembly and a housing, with the electrode assembly housed within the housing. The electrode assembly includes a cathode, an anode, and a separator. During the charge and discharge process of the battery cell, active ions (such as lithium ions) are inserted and removed between the cathode and anode. A separator, placed between the cathode and anode, reduces the risk of short circuits while allowing active ions to pass through.

[0065] The housing is used to encapsulate the electrode assembly and electrolyte components. The housing can be a steel shell, an aluminum shell, a plastic shell (such as polypropylene), a composite metal shell (such as a copper-aluminum composite shell), or an aluminum-plastic film.

[0066] In some embodiments, the cathode may be a cathode sheet, which may include a cathode current collector and a cathode active material layer disposed on at least one surface of the cathode current collector. The anode may be an anode sheet, which may include an anode current collector and an anode active material layer disposed on at least one surface of the anode current collector.

[0067] During the preparation of electrode sheets (cathode or anode), cutting (e.g., electrode sheet slitting or tab die-cutting) is typically required to achieve the desired size and shape. However, after cutting, burrs are prone to form on the current collector at the cutting locations. During the charge and discharge process of the battery cell, these burrs may puncture the separator and connect the cathode and anode, causing a short circuit risk and affecting the reliability of the battery cell.

[0068] In view of this, an embodiment of the present application provides a technical solution, which provides an insulating member on the pole piece to cover the end surface of the current collector where burrs are prone to form, thereby reducing the risk of burrs connecting the anode and cathode and improving the reliability of the battery cell.

[0069] The electrode assembly described in the embodiments of the present application is applicable to battery cells, batteries, and electrical devices using batteries.

[0070] The battery disclosed in the embodiments of the present application can be used in electrical devices that use the battery as a power source or various energy storage systems that use the battery as an energy storage element. The electrical device can be, but is not limited to, a mobile phone, a tablet, a laptop computer, an electric toy, an electric tool, a battery car, an electric car, a ship, a spacecraft, and the like. Among them, the electric toy can include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, and the like, and the spacecraft can include airplanes, rockets, space shuttles, and spacecraft, and the like.

[0071] For the convenience of description, the following embodiments are described by taking a vehicle as an example of an electrical device.

[0072] FIG1 is a schematic structural diagram of a vehicle 1 provided in some embodiments of the present application.

[0073] As shown in FIG1 , a battery 2 is provided inside the vehicle 1. The battery 2 may be provided at the bottom, head, or tail of the vehicle 1. The battery 2 may be used to power the vehicle 1. For example, the battery 2 may serve as an operating power source for the vehicle 1.

[0074] The vehicle 1 may further 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 requirements of the vehicle 1 during startup, navigation, and driving.

[0075] In some embodiments of the present application, the battery 2 can not only serve as the operating power source of the vehicle 1, but also serve as the driving power source of the vehicle 1, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1.

[0076] Figure 2 is an exploded view of a battery 2 provided in some embodiments of the present application. As shown in Figure 2 , the battery 2 includes a housing 5 and a battery cell (not shown), which is housed in the housing 5. The battery cell is the smallest unit that makes up the battery 2.

[0077] The housing 5 is used to house battery cells and can have various structures. In some embodiments, the housing 5 can include a first housing portion 5a and a second housing portion 5b. The first housing portion 5a and the second housing portion 5b overlap each other, and the first housing portion 5a and the second housing portion 5b together define a storage space 5c for accommodating the battery cells. The second housing portion 5b can be a hollow structure with one end open. The first housing portion 5a is a plate-like structure, and the first housing portion 5a overlaps the open side of the second housing portion 5b to form the housing 5 with the storage space 5c. The first housing portion 5a and the second housing portion 5b can also be hollow structures with one end open. The open side of the first housing portion 5a overlaps the open side of the second housing portion 5b to form the housing 5 with the storage space 5c. Of course, the first housing portion 5a and the second housing portion 5b can have various shapes, such as a cylinder, a rectangular parallelepiped, etc.

[0078] In order to improve the sealing performance after the first box body 5a and the second box body 5b are connected, a sealing member, such as a sealant, a sealing ring, etc., may also be provided between the first box body 5a and the second box body 5b.

[0079] Assuming that the first box body portion 5 a covers the top of the second box body portion 5 b , the first box body portion 5 a can also be called an upper box cover, and the second box body portion 5 b can also be called a lower box body 5 .

[0080] In battery 2, there can be one or more battery cells. If there are multiple battery cells, they can be connected in series, in parallel, or in a hybrid configuration. A hybrid configuration refers to a combination of series and parallel connections. Multiple battery cells can be directly connected in series, in parallel, or in a hybrid configuration, and then the entire battery module can be housed within housing 5. Alternatively, multiple battery cells can be first connected in series, in parallel, or in a hybrid configuration to form a battery module 6, and then multiple battery modules 6 can be connected in series, in parallel, or in a hybrid configuration to form a single unit housed within housing 5.

[0081] A plurality of battery cells may be directly disposed in the housing 5 to form the battery 10 , or a plurality of battery cells may first form a battery module 6 , and then a plurality of battery modules 6 may be disposed in the housing 5 to form the battery 10 .

[0082] FIG3 is an exploded schematic diagram of a battery module 6 provided in some embodiments of the present application.

[0083] As shown in FIG3 , in some embodiments, there are multiple battery cells 7 , which are first connected in series, in parallel, or in series to form a battery module 6 . The multiple battery modules 6 are then connected in series, in parallel, or in series to form an integrated battery module 6 , which is then housed in a housing 5 .

[0084] The multiple battery cells 7 in the battery module 6 can be electrically connected via a busbar component to achieve parallel connection, series connection, or mixed connection of the multiple battery cells 7 in the battery module 6 .

[0085] The battery cell 7 may be a cylindrical battery cell 7 , a square battery cell 7 , or a battery cell 7 in another shape.

[0086] As shown in FIG4 , in some embodiments, the battery cell 7 includes a housing 20 and an electrode assembly 30. The electrode assembly 30 is accommodated in the housing 20. The electrode assembly 30 is a cylindrical wound structure.

[0087] The housing 20 can have various shapes and sizes, such as a rectangular parallelepiped, a hexagonal prism, etc. Specifically, the shape of the housing 20 can be determined according to the specific shape and size of the electrode assembly 30. The housing 20 can be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, etc.

[0088] The electrode assembly 30 is a component where electrochemical reactions occur in the battery cell 7. One or more electrode assemblies 30 may be contained in the housing 20.

[0089] Some embodiments of the present application provide an electrode assembly 30, as shown in Figure 5, the electrode assembly 30 includes a first electrode sheet 301 and a second electrode sheet 302 with opposite polarities, and the first electrode sheet 301 and the second electrode sheet 302 are wound along a winding direction X; as shown in Figure 6, the first electrode sheet 301 includes a first current collector 3011 and a first active material layer 3012 arranged on the surface of the first current collector 3011, and the end of the first current collector 3011 along the winding direction X has a first end face 30111; the electrode assembly 30 also includes a first insulating member 303, the first insulating member 303 is connected to the first electrode sheet 301 and covers at least a portion of the first end face 30111.

[0090] The first electrode sheet 301 and the second electrode sheet 302 are two electrode sheets with opposite electrode characteristics, one of which is an anode electrode sheet and the other is a cathode electrode sheet. The first electrode sheet 301 and the second electrode sheet 302 are wound along a winding direction X, so that the electrode assembly 30 has a wound structure.

[0091] The first current collector 3011 may be a conductive structure formed by disposing a conductive material on an insulating substrate. For example, the conductive material on the first current collector 3011 may include a metal material, such as aluminum, an aluminum alloy, nickel, a nickel alloy, titanium, a titanium alloy, silver, or a silver alloy. The first active material layer 3012 may be a structural layer containing a polar active material.

[0092] In some examples, the first pole piece 301 may be an anode pole piece, the second pole piece 302 may be a cathode pole piece, and the first active material layer 3012 includes an anode active material, which may be an anode active material known in the art for battery cells 7. As an example, the anode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate. The silicon-based material may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. The tin-based material may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys. However, the present application is not limited to these materials, and other traditional materials that can be used as anode active materials for the battery 2 may also be used. These anode active materials may be used alone or in combination of two or more.

[0093] The first active material layer 3012 may be formed by coating the anode active material on the surface of the first current collector 3011 through a coating process.

[0094] The first end surface 30111 may be the surface of the end of the first current collector 3011 along the winding direction X, which may be formed by cutting during the electrode sheet preparation process. For example, the first end surface 30111 may intersect with the surface of the first current collector 3011 coated with the first active material.

[0095] The first insulating member 303 can be a component with insulating properties. By connecting the first insulating member 303 to the first pole piece 301 and making the first insulating member 303 cover at least a portion of the first end surface 30111, the burrs on the first end surface 30111 covered by the first insulating member 303 are covered by the first insulating member 303, thereby reducing the possibility of the burrs piercing the isolation member 305 and reducing the risk of short circuit in the battery cell 7.

[0096] Exemplarily, the first insulating member 303 may be an insulating structure having an opening, and the end of the first current collector 3011 having the first end face 30111 is inserted into the opening to cover the first end face 30111; the first insulating member 303 may also be formed by curing the insulating glue, and the insulating glue adheres to the first end face 30111 to cover the first end face 30111; the first insulating member 303 may also be formed by adhering the insulating tape to the end of the first current collector 3011 having the first end face 30111 and covering the first end face 30111.

[0097] In the above structure, since the first end face 30111 of the end of the first current collector 3011 is covered with the first insulating member 303, the first insulating member 303 can cover the burrs at the first end face 30111, thereby reducing the risk of the burrs piercing the isolation member 305 of the electrode assembly 30, and reducing the possibility of short circuit inside the battery 2, which is beneficial to improving the reliability of the battery 2.

[0098] In some embodiments, both ends of the first pole piece 301 along the winding direction X are provided with a first insulating member 303 .

[0099] By arranging the first insulating member 303 at both ends of the first pole piece 301 along the winding direction X, the first end faces 30111 at both ends of the first pole piece 301 along the winding direction X are at least partially covered by the first insulating member 303, so that the burrs on the first end faces 30111 at both ends of the first pole piece 301 can be covered, which can further reduce the risk of the burrs piercing the isolation member 305 of the electrode assembly 30, which is conducive to further improving the reliability of the battery 2.

[0100] In some embodiments, the first insulating member 303 is bonded to the first active material layer 3012 or the first current collector 3011 .

[0101] By bonding the first insulating member 303 to the first active material layer 3012 of the first electrode 301 or the first current collector 3011, the first insulating member 303 is firmly connected to the first electrode 301 and is not easily removed. For example, the first insulating member 303 can be bonded to the first active material layer 3012 or the first current collector 3011 using an adhesive such as glue.

[0102] In some embodiments, the first insulating member 303 is bonded to the first active material layer 3012. By bonding the first insulating member 303 to the surface of the first active material layer 3012, the first insulating member 303 and the first electrode 301 have a larger bonding area, which is beneficial to improving the firmness of the connection between the first insulating member 303 and the first electrode 301.

[0103] In some embodiments, the first insulating member 303 includes two oppositely arranged first insulating layers 3031 , the first insulating layer 3031 includes a first connecting portion 30311 and a first covering portion 30312 , the first covering portion 30312 is stacked on the first pole piece 301 , and the first connecting portions 30311 of the two first insulating layers 3031 are bonded to each other.

[0104] The first insulating layer 3031 may be a partial structure constituting the first insulating member 303 . The two first insulating layers 3031 are arranged opposite to each other and are respectively connected to two oppositely arranged surfaces of the end of the first pole piece 301 , so as to cover the first end surface 30111 .

[0105] As shown in FIG7 , the first insulating layer 3031 includes a first connecting portion 30311 and a first covering portion 30312 that are connected to each other. The first connecting portion 30311 and the first covering portion 30312 are sequentially arranged along the winding direction X. The first covering portion 30312 is used to connect to the first pole piece 301, and the first connecting portion 30311 is used to connect to the first connecting portion 30311 of another first insulating layer 3031 to cover the end of the first pole piece 301 where the first end surface 30111 is located.

[0106] The first covering parts 30312 of the two first insulating members 303 are adhered to the two opposite surfaces of the first pole piece 301 and are stacked on both sides of the first pole piece 301 respectively. The first connecting parts 30311 of the two first insulating layers 3031 are bonded to each other to achieve the covering of the first end face 30111 connected between the two opposite surfaces of the first pole piece 301.

[0107] Illustratively, the first insulating layer 3031 may be an insulating tape, a portion of which is adhered to the surface of the first electrode 301 , and another portion of which is bonded to another insulating tape.

[0108] In some embodiments, the thickness of the first pole piece 301 is H1, the thickness of the first insulating layer 3031 is H2,

[0109] By setting the thickness of the first pole piece 301 to H1, the thickness of the first insulating layer 3031 to H2, and The thickness of the first connecting portion 30311 in the two first insulating layers 3031 after bonding is less than or equal to the thickness of the first electrode piece 301, which is beneficial to reducing the steps of the electrode assembly 30 formed by winding and reducing the possibility of cracks in the first electrode piece 301 due to step stress.

[0110] In some embodiments, the inner end of the first pole piece 301 is connected to the first insulating member 303 , and at least a portion of the first pole piece 301 is wound around the outer side of the first insulating member 303 .

[0111] By connecting the first insulating member 303 to the inner end of the first pole piece 301 and winding at least a portion of the first pole piece 301 around the outside of the first insulating member 303, the first insulating member 303 at the inner end of the first pole piece 301 can be wound around the center of the electrode assembly 30, so that the first insulating member 303 can support the electrode assembly 30, which helps to reduce the possibility of collapse of the electrode assembly 30.

[0112] In some embodiments, along the opposite direction of the winding direction X, the length of the first insulating member 303 at the inner end of the first pole piece 301 extending from the first pole piece 301 is A1, and 0.5 mm ≤ A1 ≤ 120 mm.

[0113] The length A1 of the first insulating member 303 extending from the inner end of the first electrode piece 301 beyond the first electrode piece 301 is the length of the first connecting portion 30311 in the direction opposite to the winding direction X. By setting the range of the length A1 of the first insulating member 303 connected to the inner end of the first electrode piece 301 extending from the first electrode piece 301 in the direction opposite to the winding direction X to 0.5 mm ≤ A1 ≤ 120 mm, the first insulating member 303 connected to the inner end of the first electrode piece 301 can form a winding core with good support capabilities, thereby better supporting the center of the electrode assembly 30 and better preventing the electrode assembly 30 from collapsing.

[0114] In some embodiments, 1mm≤A1≤100mm, so that the first insulating member 303 connected to the inner end of the first pole piece 301 can not only well support the center of the electrode assembly 30, but also reduce the usage of the first insulating member 303 and reduce waste.

[0115] In some embodiments, as shown in Figure 8, the second pole piece 302 includes a second current collector 3021 and a second active material layer 3022 arranged on the surface of the second current collector 3021, and the end of the second current collector 3021 along the winding direction X has a second end face 30211; the electrode assembly 30 also includes a second insulating member 304, which is connected to the second pole piece 302 and covers at least a portion of the second end face 30211.

[0116] The second electrode piece 302 is a cathode electrode piece. The second current collector 3021 included in the second electrode piece 302 can be a conductive structure, which can be formed by disposing a conductive material on an insulating substrate. For example, the conductive material on the second current collector 3021 can include a metal material, such as aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, or silver alloy.

[0117] The second active material layer 3022 may be a structural layer containing a cathode active material, and the cathode active material may include at least one of the following materials: lithium-containing phosphates, lithium transition metal oxides, and their respective modified compounds. However, the present application is not limited to these materials, and other traditional materials that can be used as cathode active materials for battery 2 may also be used. These cathode active materials may be used alone or in combination of two or more. Examples of lithium-containing phosphates may include but are not limited to at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO4), a composite material of lithium manganese phosphate and carbon, lithium manganese iron phosphate, and a composite material of lithium manganese iron phosphate and carbon. Examples of lithium transition metal oxides may include but are not limited to lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (such as LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (also referred to as NCM 333 ), LiNi 0.5 Co 0.2 Mn 0.3 O2 (also referred to as NCM 523 ), LiNi 0.5 Co 0.25 Mn 0.25 O2 (also referred to as NCM 211 ), LiNi 0.6 Co 0.2 Mn 0.2 O2 (also referred to as NCM 622 ), LiNi 0.8 Co 0.1Mn 0.1 O2 (also referred to as NCM 811 ), lithium nickel cobalt aluminum oxide (such as LiNi 0.80 Co 0.15 Al 0.05 O2) and at least one of its modified compounds, etc.

[0118] The second end surface 30211 may be the surface of the end of the second current collector 3021 along the winding direction X, which may be formed by cutting during the electrode sheet preparation process. For example, the second end surface 30211 may intersect with the surface of the second current collector 3021 coated with the second active material.

[0119] The second insulating member 304 can be a component with insulating properties. By connecting the second insulating member 304 to the second pole piece 302 and making the second insulating member 304 cover at least a portion of the second end face 30211, the burrs on the second end face 30211 covered by the second insulating member 304 are covered by the second insulating member 304, thereby reducing the possibility of the burrs piercing the isolation member 305 and reducing the risk of short circuit in the battery cell 7.

[0120] Exemplarily, the second insulating member 304 can be an insulating structure with an opening, and the end of the second current collector 3021 having the second end face 30211 is inserted into the opening to cover the second end face 30211; the second insulating member 304 can also be formed by curing the insulating glue, and the insulating glue adheres to the second end face 30211 to achieve coverage of the second end face 30211; the second insulating member 304 can also be formed by adhering the insulating tape to the end of the second current collector 3021 having the second end face 30211 and covering the second end face 30211.

[0121] An isolation member 305 is provided between the first electrode piece 301 and the second electrode piece 302 for isolating the stacked first electrode piece 301 and the second electrode piece 302. The isolation member 305 is stacked between adjacent first electrode pieces 301 and second electrode pieces 302. For example, the isolation member 305 may be an isolation membrane. In the embodiments of the present application, any known porous isolation membrane with good chemical and mechanical stability may be selected as the isolation membrane.

[0122] As an example, the primary material of the isolation membrane can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramic. The isolation membrane can be a single-layer film or a multi-layer composite film. When the isolation membrane is a multi-layer composite film, the materials of each layer can be the same or different. The isolation member 305 can be a separate component located between the first and second pole pieces 301, 302, or it can be attached to the surfaces of the first and second pole pieces 301, 302.

[0123] In some embodiments, the separator 305 may also be a solid electrolyte. The solid electrolyte is disposed between the first electrode 301 and the second electrode 302 and serves to transmit ions and isolate the first electrode 301 from the second electrode 302 .

[0124] In some embodiments, the elastic modulus of the first insulating member 303 is greater than the elastic modulus of the first pole piece 301 , and the elastic modulus of the second insulating member 304 is greater than the elastic modulus of the second pole piece 302 .

[0125] By configuring the elastic modulus of the first insulating member 303 to be greater than the elastic modulus of the first pole piece 301, and configuring the elastic modulus of the second insulating member 304 to be greater than the elastic modulus of the second pole piece 302, the first insulating member 303 connected to the inner end of the first pole piece 301 can better support the center of the electrode assembly 30, and the second insulating member 304 connected to the inner end of the second pole piece 302 can better support the center of the electrode assembly 30, which is beneficial to reducing the possibility of collapse of the electrode assembly 30.

[0126] For example, the elastic modulus of the first insulating member 303 and the second insulating member 304 may be Young's modulus, which may be obtained by measurement according to the national standard GB / T 1447-2005. The specific measurement method may refer to the national standard GB / T 1447-2005 and will not be repeated here.

[0127] In some embodiments, the first electrode piece 301 is an anode electrode piece, the second electrode piece 302 is a cathode electrode piece, and in the opposite direction of the winding direction X, the first insulating member 303 extends out from the second insulating member 304 .

[0128] In the cylindrical wound electrode assembly 30 , the anode electrode sheet generally extends beyond the cathode electrode sheet in the winding direction X. By configuring the first electrode sheet 301 as the anode electrode sheet and the second electrode sheet 302 as the cathode electrode sheet, and making the first insulating member 303 extend beyond the second insulating member 304 in the opposite direction of the winding direction X, the first insulating member 303 connected to the anode electrode sheet can be longer than the second insulating member 304 at the center of the electrode assembly 30 and wound into the center of the electrode assembly 30.

[0129] In some embodiments, in the thickness direction of the first pole piece 301 , the thickness of the first insulating member 303 is H3 , the thickness of the second insulating member 304 is F3 , and H3 > F3 .

[0130] By configuring the thickness H3 of the first insulating member 303 in the thickness direction of the first pole piece 301 to be greater than the thickness of the second insulating member F3, the first insulating member 303 at the inner end of the first pole piece 301 wound around the center of the electrode assembly 30 can provide greater supporting force, which is beneficial to improving the effect of reducing collapse.

[0131] In some embodiments, in the opposite direction of the winding direction X, the first insulating member 303 is located inside the second insulating member 304 .

[0132] By arranging the first insulating member 303 on the inner side of the second insulating member 304 in the opposite direction of the winding direction X, the first insulating member 303 is located on the inner side of the second insulating member 304 as a whole. This not only allows the anode electrode to extend beyond the cathode electrode in the winding direction X, but also allows the first insulating member 303 connected to the inner end of the first electrode 301 to be better wound around the center of the electrode assembly 30, thereby better playing a supporting role.

[0133] In some embodiments, the elastic modulus of the first insulating member 303 is greater than the elastic modulus of the second insulating member 304 .

[0134] By configuring the elastic modulus of the first insulating member 303 to be greater than the elastic modulus of the second insulating member 304, the first insulating member 303 connected to the inner end of the first pole piece 301 can provide a greater elastic restoring force after winding to support the center of the electrode assembly 30, so that the first insulating member 303 can better reduce the possibility of collapse of the electrode assembly 30.

[0135] In some embodiments, a second insulating member 304 is provided at both ends of the second pole piece 302 along the winding direction X.

[0136] By arranging the second insulating member 304 at both ends of the second pole piece 302 along the winding direction X, the second end faces 30211 at both ends of the second pole piece 302 along the winding direction X are at least partially covered by the second insulating member 304, so that the burrs on the second end faces 30211 at both ends of the second pole piece 302 can be covered, which can further reduce the risk of the burrs piercing the isolation member 305 of the electrode assembly 30, which is conducive to further improving the reliability of the battery 2.

[0137] In some embodiments, the second insulating member 304 at the inner end of the second pole piece 302 extends from the second pole piece 302 by a length B1 , and the second insulating member 304 at the outer end of the second pole piece 302 extends from the second pole piece 302 by a length B4 , where B1 > B4 .

[0138] By setting the length of the second insulating member 304 at the inner end of the second pole piece 302 extending from the second pole piece 302 to B1, and setting the length of the second insulating member 304 at the outer end of the second pole piece 302 extending from the second pole piece 302 to B4, and making B1>B4, the second insulating member 304 can have a good supporting effect while reducing waste.

[0139] In some embodiments, the second insulating member 304 includes two oppositely disposed second insulating layers 3041 , each of which includes a second connecting portion 30411 and a second covering portion 30412 . The second covering portion 30412 is stacked on the second electrode 302 , and the second connecting portions 30411 of the two second insulating layers 3041 are bonded to each other.

[0140] As shown in FIG9 , the second insulating layer 3041 includes a second connecting portion 30411 and a second covering portion 30412 connected to each other, and the second connecting portion 30411 and the second covering portion 30412 are sequentially arranged along the winding direction X. The second covering portion 30412 is used to connect to the second pole piece 302, and the second connecting portion 30411 is used to connect to the second connecting portion 30411 of another second insulating layer 3041 to cover the end of the second pole piece 302 where the second end surface 30211 is located.

[0141] The second covering parts 30412 of the two second insulating members 304 are adhered to the two opposite surfaces of the second pole piece 302 and are stacked on both sides of the second pole piece 302. The second connecting parts 30411 of the two second insulating layers 3041 are bonded to each other to achieve the covering of the second end face 30211 connected between the two opposite surfaces of the second pole piece 302.

[0142] The length B1 of the second insulating member 304 at the inner end of the second pole piece 302 extending from the second pole piece 302 is the length of the second connecting portion 30411 at the inner end of the second pole piece 302 in the direction opposite to the winding direction X. The length B4 of the second insulating member 304 at the outer end of the second pole piece 302 extending from the second pole piece 302 is the length of the second connecting portion 30411 at the outer end of the second pole piece 302 in the winding direction X.

[0143] In some embodiments, the length B1 of the second insulating member 304 at the inner end of the second pole piece 302 extending from the second pole piece 302 (the length of the second connecting portion 30411 at the inner end of the second pole piece 302 in the opposite direction of the winding direction X) is configured to be in the range of 0.5mm≤B1≤120mm. By configuring the length B1 of the second insulating member 304 at the inner end of the second pole piece 302 extending from the second pole piece 302 to be in the range of 0.5mm≤B1≤120mm, the second insulating member 304 at the inner end of the second pole piece 302 can extend into the center of the electrode assembly 30 by a sufficient length, which is beneficial to improving its supporting effect on the electrode assembly 30 without being too long and causing waste. In some embodiments, the length B1 of the second insulating member 304 at the inner end of the second pole piece 302 extending from the second pole piece 302 is configured to be in the range of 1mm≤B1≤100mm, so that the second insulating member 304 at the inner end of the second pole piece 302 can better support the electrode assembly 30 while not being too long and causing waste.

[0144] In some embodiments, the length B4 by which the second insulating member 304 at the outer end of the second pole piece 302 extends from the second pole piece 302 (the length of the second connecting portion 30411 at the outer end of the second pole piece 302 in the winding direction X) is configured to be 0.5 mm ≤ B4 ≤ 10 mm. By configuring the length B4 by which the second insulating member 304 at the outer end of the second pole piece 302 extends from the second pole piece 302 to be 0.5 mm ≤ B4 ≤ 10 mm, the second insulating member 304 at the outer end of the second pole piece 302 can cover the second end surface 30211 at the outer end of the second pole piece 302 while reducing waste of the second insulating member 304. In some embodiments, the length B4 by which the second insulating member 304 at the outer end of the second pole piece 302 extends from the second pole piece 302 is configured to be 1 mm ≤ B4 ≤ 6 mm, so that the second insulating member 304 at the outer end of the second pole piece 302 can both cover the second end surface 30211 at the outer end of the second pole piece 302 and reduce waste of the second insulating member 304.

[0145] Illustratively, the second insulating layer 3041 may be an insulating tape, two parts of the insulating tape are adhered to the surface of the second electrode 302 , and the other part is bonded to another insulating tape.

[0146] In some embodiments, in the winding direction X, the length of the first covering portion 30312 at the inner end of the first pole piece 301 is A2, and the length of the second covering portion 30412 at the inner end of the second pole piece 302 is B2, where B2<A2.

[0147] The length A2 of the first covering portion 30312 at the inner end of the first pole piece 301 is the length of the portion of the first insulating member 303 at the inner end of the first pole piece 301 covering the first pole piece 301 along the winding direction X. The length B2 of the second covering portion 30412 at the inner end of the second pole piece 302 is the length of the portion of the second insulating member 304 at the inner end of the second pole piece 302 covering the second pole piece 302 along the winding direction X. By setting B2 < A2, the area of ​​the second insulating member 304 at the inner end of the second pole piece 302 covering the second pole piece 302 can be reduced, which helps to reduce the capacity loss caused by the provision of the second insulating member 304.

[0148] Exemplarily, the length A2 of the first covering portion 30312 at the inner end of the first pole piece 301 is configured to be in the range of 0.5 mm ≤ A2 ≤ 120 mm. By configuring the length A2 of the first covering portion 30312 at the inner end of the first pole piece 301 to be in the range of 0.5 mm ≤ A2 ≤ 120 mm, the first insulating member 303 at the inner end of the first pole piece 301 has a sufficient bonding area with the first pole piece 301 while not wasting the first pole piece 301 due to an excessive bonding area. This allows the first insulating member 303 to be firmly bonded to the first pole piece 301 through the first covering portion 30312 without wasting the functional area of ​​the first pole piece 301. In some embodiments, the length A2 of the first covering portion 30312 at the inner end of the first pole piece 301 is configured to be in the range of 1 mm ≤ A2 ≤ 100 mm. This allows the first insulating member 303 to be firmly bonded to the first pole piece 301 without wasting the area of ​​the first pole piece 301.

[0149] The length B2 of the second covering portion 30412 at the inner end of the second pole piece 302 is configured to be within a range of 0.5 mm ≤ B2 ≤ 10 mm. By configuring the length B2 of the second covering portion 30412 at the inner end of the second pole piece 302 to be within a range of 0.5 mm ≤ B2 ≤ 10 mm, the second insulating member 304 at the inner end of the second pole piece 302 has a sufficient bonding area with the second pole piece 302 while also reducing the coverage of the second pole piece 302. This allows the second insulating member 304 to be firmly bonded to the second pole piece 302 through the second covering portion 30412 without excessively covering the second pole piece 302. In some embodiments, the length B2 of the second covering portion 30412 at the inner end of the second pole piece 302 is configured to be within a range of 1 mm ≤ B2 ≤ 6 mm. This allows the second insulating member 304 to be firmly bonded to the second pole piece 302 while not wasting the area of ​​the second pole piece 302.

[0150] Exemplarily, the range of the length A3 of the first covering portion 30312 at the outer end of the first pole piece 301 is configured to be 0.5 mm ≤ A3 ≤ 120 mm. By configuring the range of the length A3 of the first covering portion 30312 at the outer end of the first pole piece 301 to be 0.5 mm ≤ A3 ≤ 120 mm, the first insulating member 303 at the outer end of the first pole piece 301 has a sufficient bonding area with the first pole piece 301 while not wasting the first pole piece 301 due to an excessive bonding area. This allows the first insulating member 303 to be firmly bonded to the first pole piece 301 through the first covering portion 30312 without wasting the functional area of ​​the first pole piece 301. In some embodiments, the range of the length A3 of the first covering portion 30312 at the outer end of the first pole piece 301 is configured to be 1 mm ≤ A3 ≤ 100 mm. This allows the first insulating member 303 to be firmly bonded to the first pole piece 301 without wasting the area of ​​the first pole piece 301.

[0151] Exemplarily, the range of the length A4 of the first connecting portion 30311 at the outer end of the first pole piece 301 is configured to be 0.5 mm ≤ A4 ≤ 120 mm. By configuring the range of the length A4 of the first connecting portion 30311 at the outer end of the first pole piece 301 to be 0.5 mm ≤ A4 ≤ 120 mm, the first connecting portion 30311 at the outer end of the first pole piece 301 can cover the first end surface 30111 at the outer end of the first pole piece 301 while reducing waste of the first insulating member 303. In some embodiments, the range of the length A4 of the first connecting portion 30311 at the outer end of the first pole piece 301 is configured to be 1 mm ≤ A4 ≤ 100 mm, so that the first connecting portion 30311 at the outer end of the first pole piece 301 can both cover the first end surface 30111 at the outer end of the first pole piece 301 and reduce waste of the first insulating member 303.

[0152] In some embodiments, the electrode assembly 30 is a cylindrical structure.

[0153] The cylindrical structure formed by the configuration of the electrode assembly 30 may be formed by stacking the first electrode piece 301 , the second electrode piece 302 and the separator 305 in the electrode assembly 30 and then winding them along the winding direction X.

[0154] In some embodiments, the first pole piece 301 further includes a first pole tab 3013 connected to the first current collector 3011 . The first pole tab 3013 includes a flattened area 30131 . The flattened area 30131 is spaced apart from the first insulating member 303 .

[0155] The first electrode tab 3013 may be a portion of the first current collector 3011 on the surface of which the first active material layer 3012 is not provided, and may be used to connect with other components in the battery cell 7 .

[0156] The first electrode tab 3013 is flattened to obtain a flattened area 30131, which can make the end of the electrode assembly 30 in the direction perpendicular to the winding direction X flat, reduce the possibility of the occurrence of sharp-angle structures, and facilitate the subsequent welding of the collecting plate at the end of the electrode assembly 30 in the direction perpendicular to the winding direction X, thereby ensuring the welding quality.

[0157] The interval arrangement between the flattened area 30131 and the first insulating member 303 may mean that the first insulating member 303 is not set in the flattened area 30131 of the first electrode 3013, so that the flattened area 30131 and the first insulating member 303 are separated, so that the first insulating member 303 does not affect the connection between the flattened area 30131 and the collecting plate.

[0158] In some embodiments, as shown in Figure 10, in a direction perpendicular to the winding direction X, the first insulating member 303 can extend from the side of the first pole piece 301 where the first pole tab 3013 is provided, from the first active material layer 3012 to the surface of the first pole tab 3013, so that the first insulating member 303 can cover a larger area of ​​the first end surface 30111, which is beneficial for covering more burrs on the first end surface 30111, and is beneficial for further reducing the risk of burrs piercing the isolation member 305 of the electrode assembly 30.

[0159] Illustratively, in a direction perpendicular to the winding direction X, the first insulating member 303 extends beyond the first active material layer 3012 by a length G1, G1≤4 mm, so that the first insulating member 303 can better avoid the flattened area 30131 of the first electrode tab 3013 .

[0160] As shown in FIG11 , the first insulating member 303 may not extend from the side of the first electrode sheet 301 where the first electrode tab 3013 is provided, so that the first insulating member 303 can better avoid the flattened area 30131 of the first electrode tab 3013 and is less likely to affect or change the structure of the first electrode tab 3013. In some embodiments, the length of the first insulating member 303 from the edge of the first active material layer 3012 is G2, where G2 is ≤ 4 mm. This allows the first insulating member 303 to cover a larger area of ​​the first end surface 30111, facilitating coverage of more burrs on the first end surface 30111 and further reducing the risk of burrs piercing the separator 305 of the electrode assembly 30.

[0161] In some embodiments, the first insulating member 303 may extend from the first active material layer 3012 on a side of the first electrode sheet 301 away from the first electrode tab 3013 in a direction perpendicular to the winding direction X. This allows the first insulating member 303 to better cover the first end surface 30111, facilitating coverage of more burrs on the first end surface 30111 and further reducing the risk of burrs piercing the separator 305 of the electrode assembly 30. Exemplarily, the first insulating member 303 extends from the first active material layer 3012 on the side of the first electrode sheet 301 away from the first electrode tab 3013 by an angle I1, where I1 ≤ 4 mm. This reduces the amount of the first insulating member 303 used and reduces material waste.

[0162] For example, in the direction perpendicular to the winding direction X, the first insulating member 303 may not extend from the side of the first pole piece 301 away from the first pole ear 3013, and the length of the first insulating member 303 from the edge of the first active material layer 3012 is I, I≤4mm, so that the first insulating member 303 can cover a larger area of ​​the first end surface 30111, which is beneficial for covering more burrs on the first end surface 30111, and is beneficial for further reducing the risk of burrs piercing the isolation member 305 of the electrode assembly 30.

[0163] Some embodiments of the present application further provide a battery cell 7, comprising a housing 20 and at least one electrode assembly 30 provided by the above technical solution, wherein the electrode assembly 30 is accommodated in the housing 20. Since the battery cell 7 includes the electrode assembly 30 provided by the above technical solution, the battery cell 7 has good reliability.

[0164] Some embodiments of the present application further provide a battery 2, which includes the battery cell 7 provided by the above technical solution. Since the battery 2 includes the battery cell 7 provided by the above technical solution, the battery 2 has good reliability.

[0165] Some embodiments of the present application further provide an electrical device, which includes the battery 2 provided by the above technical solution, and is used to provide electrical energy. The electrical device can be any of the aforementioned devices or systems using the battery 2.

[0166] Some embodiments of the present application further provide a method for manufacturing an electrode assembly 30, the method comprising the following steps:

[0167] S1. Provide multiple first pole pieces 301 and insulating members. The first pole piece 301 includes a first current collector 3011 and a first active material layer 3012 arranged on the surface of the first current collector 3011. The end of the first current collector 3011 along its own length direction has a first end surface 30111.

[0168] The provided first electrode sheet 301 may be the first electrode sheet 301 in the aforementioned technical solution, and includes a first current collector 3011 and a first active material layer 3012 disposed on a surface of the first current collector 3011. Each first electrode sheet 301 is used to form an electrode assembly 30. The first current collector 3011 in the first electrode sheet 301 has a first end surface 30111 at its end along its length. The insulating member may be an insulating structure used to connect two first electrode sheets 301.

[0169] Step S1 can provide materials for manufacturing the electrode assembly 30 , facilitating subsequent processing and manufacturing of the electrode assembly 30 .

[0170] S2. Connect two adjacent first pole pieces 301 through an insulating member, and the insulating member covers at least a portion of the first end surface 30111.

[0171] In step S2, the plurality of first electrode sheets 301 are sequentially connected along the length of the first electrode sheets 301 to form a long strip-like structure. Two adjacent first electrode sheets 301 are connected by an insulating member, which covers at least a portion of the first end surface 30111 of the first current collector 3011. This ensures that the insulating member covers at least a portion of the burrs on the first end surface 30111, thereby reducing the possibility of the insulating member puncturing the separator 305 after winding to form the electrode assembly 30.

[0172] S3 , winding the first pole piece 301 and the insulating member in the length direction of the first current collector 3011 .

[0173] In step S2 , the long strip structure including the plurality of first pole pieces 301 and the insulating member is wound to form a cylindrical wound structure.

[0174] S4 , cutting the insulating member between two adjacent first pole pieces 301 to form first insulating members 303 at both ends of the first pole piece 301 in the winding direction X, wherein the first insulating member 303 covers at least a portion of the first end surface 30111 .

[0175] Through the above-mentioned step S4, after a first pole piece 301 is wound to form a winding structure, the insulating member between the first pole piece 301 and the adjacent first pole piece 301 is cut in the middle, so that the insulating member is divided into first insulating members 303 connected to the two adjacent first pole pieces 301 at both ends in the winding direction X, and the first insulating member 303 covers at least part of the first end face 30111.

[0176] According to some embodiments of the present application, an electrode assembly 30 is provided in the embodiments of the present application, wherein the electrode assembly 30 includes a first electrode piece 301, a second electrode piece 302, a separator 305, a first insulating member 303 and a second insulating member 304, the first electrode piece 301, the second electrode piece 302 and the separator 305 are stacked, the separator 305 is arranged between the first electrode piece 301 and the second electrode piece 302, the first electrode piece 301 includes a first current collector 3011 and a first active material layer 3012 arranged on the surface of the first current collector 3011 The first current collector 3011 has a first end surface 30111 at its end along the winding direction X. The first insulating member 303 is connected to the first pole piece 301 and covers at least a portion of the first end surface 30111. The second pole piece 302 includes a second current collector 3021 and a second active material layer 3022 disposed on a surface of the second current collector 3021. The second current collector 3021 has a second end surface 30211 at its end along the winding direction X. The second insulating member 304 is connected to the second pole piece 302 and covers at least a portion of the second end surface 30211. The first insulating member 303 is connected to the inner end of the first pole piece 301, and at least a portion of the first pole piece 301 is wound around the outer side of the first insulating member 303. In the above structure, since the first end face 30111 of the end of the first current collector 3011 is covered with the first insulating member 303, the first insulating member 303 can cover the burrs at the first end face 30111, thereby reducing the risk of the burrs piercing the isolation member 305 of the electrode assembly 30, reducing the possibility of short circuit inside the battery 2, and helping to improve the reliability of the battery 2.

[0177] 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 make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions 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. An electrode assembly comprising a first electrode sheet and a second electrode sheet having opposite polarities, wherein the first electrode sheet and the second electrode sheet are wound along a winding direction; The first pole piece includes a first current collector and a first active material layer disposed on a surface of the first current collector, and the end of the first current collector along the winding direction has a first end surface; The electrode assembly further includes a first insulating member connected to the first electrode piece and covering at least a portion of the first end surface.

2. The electrode assembly according to claim 1, wherein The first insulating member is provided at both ends of the first pole piece along the winding direction.

3. The electrode assembly according to any one of claims 1 to 2, wherein: The first insulating member is bonded to the first active material layer or the first current collector.

4. The electrode assembly according to any one of claims 1 to 3, wherein: The first insulating member includes two first insulating layers arranged opposite to each other. The first insulating layer includes a first connecting portion and a first covering portion. The first covering portion is stacked on the first pole piece. The first connecting portions of the two first insulating layers are bonded to each other.

5. The electrode assembly according to claim 4, wherein The thickness of the first pole piece is H1, the thickness of the first insulating layer is H2, 6. The electrode assembly according to any one of claims 1 to 5, wherein: The inner end of the first pole piece is connected to the first insulating member, and at least a portion of the first pole piece is wound around the outer side of the first insulating member.

7. The electrode assembly according to claim 6, wherein: Along the direction opposite to the winding direction, the length of the first insulating member at the inner end of the first pole piece extending out of the first pole piece is A1, and 0.5 mm ≤ A1 ≤ 120 mm.

8. The electrode assembly according to any one of claims 1 to 7, wherein: The second pole piece includes a second current collector and a second active material layer arranged on the surface of the second current collector, and the end of the second current collector along the winding direction has a second end surface; the electrode assembly also includes a second insulating member, which is connected to the second pole piece and covers at least a portion of the second end surface.

9. The electrode assembly according to claim 8, wherein The elastic modulus of the first insulating member is greater than the elastic modulus of the first pole piece, and the elastic modulus of the second insulating member is greater than the elastic modulus of the second pole piece.

10. The electrode assembly according to claim 8, wherein The first pole piece is an anode pole piece, the second pole piece is a cathode pole piece, and the first insulating member extends out from the second insulating member in the opposite direction of the winding direction.

11. The electrode assembly according to claim 10, wherein: In the thickness direction of the first pole piece, the thickness of the first insulating member is H3, the thickness of the second insulating member is F3, and H3>F3.

12. The electrode assembly according to any one of claims 10 to 11, wherein: In the opposite direction to the winding direction, the first insulating member is located inside the second insulating member.

13. The electrode assembly according to any one of claims 10 to 12, wherein: The elastic modulus of the first insulating member is greater than the elastic modulus of the second insulating member.

14. The electrode assembly according to any one of claims 10 to 13, wherein: The second insulating member is provided at both ends of the second pole piece along the winding direction.

15. The electrode assembly according to claim 14, wherein The second insulating member at the inner end of the second pole piece extends out of the second pole piece by a length B1 , and the second insulating member at the outer end of the second pole piece extends out of the second pole piece by a length B4 , where B1 > B4 .

16. The electrode assembly according to any one of claims 1 to 15, wherein: The electrode assembly is a cylindrical structure.

17. The electrode assembly according to any one of claims 1 to 16, wherein: The first pole piece further includes a first pole tab connected to the first current collector. The first pole tab includes a flattened area. The flattened area is spaced apart from the first insulating member.

18. A battery cell, wherein: include: shell; At least one electrode assembly according to any one of claims 1 to 17 is housed in the housing.

19. A battery, wherein: Comprising the battery cell as claimed in claim 18.

20. An electrical device, wherein: The battery of claim 19 is provided for providing electrical energy.

21. A method for manufacturing an electrode assembly, comprising: Providing a plurality of first pole pieces and insulating members, wherein the first pole piece includes a first current collector and a first active material layer disposed on a surface of the first current collector, and the first current collector has a first end surface at an end portion along its length direction; connecting two adjacent first pole pieces via the insulating member, wherein the insulating member covers at least a portion of the first end surface; Winding the first pole piece and the insulating member in the length direction of the first current collector; The insulating member between two adjacent first pole pieces is cut to form first insulating members at both ends of the first pole piece in a winding direction, and the first insulating member covers at least a portion of the first end surface.

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