Electrode assembly, battery cell, battery and electric device

Abstract

An electrode assembly (30) and a manufacturing method thereof, a battery cell (7), a battery and an electric device, the electrode assembly (30) comprising a first pole piece (301) and a second pole piece (302) having opposite polarities and a first insulator (303), the first pole piece (301) and the second pole piece (302) being wound along a winding direction, the first pole piece (301) comprising a first current collector (3011) and a first active material layer (3012) disposed on the surface of the first current collector (3011), the second pole piece (302) comprising a second active material layer (3012) disposed on the surface of the second current collector (3011), and the first insulator (303) comprising a second active material layer (3012) disposed on the surface of the second current collector (3011). The end part of the first current collector (3011) along the winding direction is provided with a first end surface (30111); the first insulating part (303) is connected to the first pole piece (301) and covers at least part of the first end surface (30111); in the above structure, since the first end face (30111) of the end portion of the first current collector (3011) is covered with the first insulating member (303), and the first insulating member (303) can wrap burrs at the first end face (30111), the risk that the burrs pierce a separator (305) of the electrode assembly (30) is reduced, the possibility of short circuit in the battery is reduced, and improvement of the reliability of the battery is facilitated.

Description

[0001] Cross - reference to related applications

[0002] This application claims the priority of Chinese Patent Application No. 202410160635.1, titled "Electrode Assembly and Its Manufacturing Method, Battery Cell, Battery, and Electric Appliance", filed on February 4, 2024. The entire content of this application is incorporated herein by reference. Technical field

[0003] This application relates to the technical field of batteries, and particularly to an electrode assembly, a battery cell, a battery, and an electric appliance. Background art

[0004] Batteries have advantages such as high specific energy and high power density, and are widely used in electronic devices and transportation means, such as mobile phones, laptop computers, battery cars, electric vehicles, electric airplanes, electric ships, and electric tools, etc.

[0005] With the continuous expansion of the application scope of batteries, people's requirements for the reliability of batteries are also getting higher and higher. How to improve the reliability of batteries has attracted more and more attention from those skilled in the art. Summary of the utility model

[0006] In view of the above problems, this application provides an electrode assembly, a battery cell, a battery, and an electric appliance. This electrode assembly is beneficial to improving the reliability of the battery.

[0007] In a first aspect, this application provides an electrode assembly. The electrode assembly includes a first electrode tab and a second electrode tab with opposite polarities, and the first electrode tab and the second electrode tab are wound along the winding direction; the first electrode tab includes a first current collector and a first active material layer provided on the surface of the first current collector, and the end of the first current collector along the winding direction has a first end face; the electrode assembly further includes a first insulating member, and the first insulating member is connected to the first electrode tab and covers at least a part of the first end face. In the above structure, since the first end face at the end of the first current collector is covered with the first insulating member, the first insulating member can wrap the burrs at the first end face, reducing the risk of the burrs piercing the separator of the electrode assembly, reducing the possibility of short - circuit inside the battery, and being beneficial to improving the reliability of the battery.

[0008] According to the electrode assembly provided by some embodiments of this application, first insulating members are provided at both ends of the first electrode tab along the winding direction, so that the burrs on the first end faces at both ends of the first electrode tab can be wrapped, which can further reduce the risk of the burrs piercing the separator of the electrode assembly, and is beneficial to further improving the reliability of the battery.

[0009] According to the electrode assembly provided by 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 connection of the first insulating member on the first electrode tab is firm and not easy to fall off.

[0010] According to the electrode assembly provided by 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 laminated on the first electrode tab, 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 two opposite surfaces connected to the first electrode tab.

[0011] According to the electrode assembly provided by some embodiments of the present application, the thickness of the first electrode tab is H1, and the thickness of the first insulating layer is H2. It is beneficial to reduce the appearance of steps in the wound electrode assembly, and reduce the possibility of cracks in the first electrode tab due to step stress.

[0012] According to the electrode assembly provided by some embodiments of the present application, the inner end of the first electrode tab is connected with a first insulating member, and at least a part of the first electrode tab is wound outside the first insulating member, so that the first insulating member at the inner end of the first electrode tab can be wound at the center of the electrode assembly, so that the first insulating member can play a supporting role for the electrode assembly, which is beneficial to reducing the possibility of the electrode assembly collapsing.

[0013] According to the electrode assembly provided by some embodiments of the present application, along the reverse direction of the winding direction, the length of the first insulating member extending from the inner end of the first electrode tab beyond the first electrode tab is A1, and 0.5 mm ≤ A1 ≤ 120 mm.

[0014] According to the electrode assembly provided by some embodiments of the present application, the second electrode tab includes a second current collector and a second active material layer provided on the surface of the second current collector. The end of the second current collector along the winding direction has a second end face; the electrode assembly further includes a second insulating member, and the second insulating member is connected to the second electrode tab and covers at least a part of the second end face, so that the burrs at 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 separator and reducing the risk of short circuit of the battery cell.

[0015] According to the electrode assembly provided by some embodiments of the present application, the elastic modulus of the first insulating member is greater than the elastic modulus of the first electrode tab, and the elastic modulus of the second insulating member is greater than the elastic modulus of the second electrode tab, so that the first insulating member connected to the inner end of the first electrode tab can better support at the center of the electrode assembly, and the second insulating member connected to the inner end of the second electrode tab can better support at the center of the electrode assembly, which is beneficial to reducing the possibility of the electrode assembly collapsing.

[0016] According to the electrode assembly provided by some embodiments of the present application, the first pole piece is an anode pole piece, and the second pole piece is a cathode pole piece. In the opposite direction of the winding direction, the first insulating member extends beyond the second insulating member, so that the first insulating member connected to the anode pole piece can be longer than the second insulating member at the center of the electrode assembly and be wound into the center of the electrode assembly.

[0017] According to the electrode assembly provided by 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, and H3 > F3, so that the first insulating member at the inner end of the first pole piece wound around the center of the electrode assembly can provide greater support force, which is beneficial to improving the effect of reducing collapse.

[0018] According to the electrode assembly provided by some embodiments of the present application, in the opposite direction of the winding direction, the first insulating member is located inside the second insulating member, so that the first insulating member is entirely located inside the second insulating member. This not only enables the anode pole piece to extend beyond the cathode pole piece in the winding direction, but also enables the first insulating member connected to the inner end of the first pole piece to be better wound around the center of the electrode assembly and can better play a supporting role.

[0019] According to the electrode assembly provided by some embodiments of the present application, the elastic modulus of the first insulating member is greater than that of the second insulating member, so that the first insulating member connected to the inner end of the first pole piece can provide greater elastic restoring force to support at the center of the electrode assembly after winding, and enables the first insulating member to better reduce the possibility of collapse of the electrode assembly.

[0020] According to the electrode assembly provided by some embodiments of the present application, second insulating members are 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 separator of the electrode assembly and is beneficial to further improving the reliability of the battery.

[0021] According to the electrode assembly provided by some embodiments of the present application, the length by which the second insulating member at the inner end of the second pole piece extends beyond the second pole piece is B1, and the length by which the second insulating member at the outer end of the second pole piece extends beyond the second pole piece is B4, and B1 > B4, which can enable the second insulating member to have a good supporting effect while reducing waste.

[0022] According to the electrode assembly provided by some embodiments of the present application, the electrode assembly is a cylindrical structure.

[0023] According to the electrode assembly provided by some embodiments of the present application, the first pole piece further includes a first pole ear connected to the first current collector. The first pole ear includes a flattened area, and the flattened area is spaced apart from the first insulating member, so that the flattened area and the first insulating member are in a separated state, and the first insulating member will not affect the connection between the flattened area and the current collecting plate.

[0024] In a second aspect, the present application provides a battery cell, which includes a housing and at least one electrode assembly provided in any of the above technical solutions, and is accommodated in the housing.

[0025] In a third aspect, the present application provides a battery, which includes the battery cell provided in the above technical solution.

[0026] In a fourth aspect, the present application provides an electrical device, which includes the battery provided in the above technical solution, and the battery is used to provide electrical energy.

[0027] In a fifth aspect, the present application provides a manufacturing method of an electrode assembly, and the manufacturing method of the electrode assembly includes the following steps:

[0028] Provide a plurality of first electrode foils and insulating members. The first electrode foil includes a first current collector and a first active material layer provided on the surface of the first current collector. The end of the first current collector in its own length direction has a first end face;

[0029] Connect two adjacent first electrode foils through an insulating member, and the insulating member covers at least a part of the first end face;

[0030] Wind the first electrode foil and the insulating member in the length direction of the first current collector;

[0031] Cut the insulating member between two adjacent first electrode foils so that first insulating members are formed at both ends of the first electrode foil in the winding direction, and the first insulating members cover at least a part of the first end face.

[0032] The technical solutions provided by the embodiments of the present disclosure at least bring the following beneficial effects:

[0033] The present application provides an electrode assembly, which includes a first electrode foil and a second electrode foil with opposite polarities and a first insulating member. The first electrode foil and the second electrode foil are wound in the winding direction. The first electrode foil includes a first current collector and a first active material layer provided on the surface of the first current collector. The end of the first current collector in the winding direction has a first end face, and the first insulating member is connected to the first electrode foil and covers at least a part of the first end face. In the above structure, since the first end face at the end of the first current collector is covered with the first insulating member, the first insulating member can wrap the burrs at the first end face, reducing the risk of the burrs piercing the separator of the electrode assembly, reducing the possibility of short circuit inside the battery, and being beneficial to improving the reliability of the battery.

[0034] The above description is only an overview of the technical solutions of the present application. In order to be able to understand the technical means of the present application more clearly, it can be implemented according to the content of the specification. And in order to make the above and other purposes, features and advantages of the present application more obvious and understandable, the following specifically illustrates the specific embodiments of the present application. Brief Description of the Drawings

[0035] By reading the following detailed description of the preferred embodiments, various other advantages and benefits will become clear to those of ordinary skill in the art. The drawings are only for the purpose of showing the preferred embodiments and are not considered to be a limitation of the present application. Also, throughout the drawings, the same reference numerals are used to represent the same components.

[0036] Figure 1 Schematic structural diagram of a vehicle provided by some embodiments of the present application;

[0037] Figure 2 Exploded view of a battery provided by some embodiments of the present application;

[0038] Figure 3 Exploded view of a battery module provided by some embodiments of the present application;

[0039] Figure 4 Cross-sectional view of a battery cell provided by some embodiments of the present application;

[0040] Figure 5 Cross-sectional view of an electrode assembly in a battery cell provided by some embodiments of the present application;

[0041] Figure 6 Cross-sectional view of a first pole piece provided by some embodiments of the present application;

[0042] Figure 7 Cross-sectional view after connection of a first insulating member and a first pole piece provided by some embodiments of the present application;

[0043] Figure 8 Cross-sectional view of a second pole piece provided by some embodiments of the present application;

[0044] Figure 9 Cross-sectional view after connection of a second insulating member and a second pole piece provided by some embodiments of the present application;

[0045] Figure 10 Top view of the first end face of a first pole piece provided by some embodiments of the present application;

[0046] Figure 11 Top view of the first end face of a first pole piece provided by some other embodiments of the present application.

[0047] In the drawings:

[0048] 1. Vehicle; 2. Battery; 3. Controller; 4. Motor; 5. Box; 5a. First box part; 5b. Second box part; 5c. Accommodating space; 6. Battery module; 7. Battery cell; 20. Outer shell; 30. Electrode assembly; 301. First electrode plate; 3011. First current collector; 30111. First end face; 3012. First active material layer; 3013. First tab; 30131. Smoothed area; 302. Second electrode plate; 3021. Second current collector; 30211. Second end face; 3022. Second active material layer; 303. First insulating member; 3031. First insulating layer; 30311. First connecting part; 30312. First covering part; 304. Second insulating member; 3041. Second insulating layer; 30411. Second connecting part; 30412. Second covering part; 305. Separator; X. Winding direction. Detailed implementation manners

[0049] The embodiments of the technical solutions of the present application will be described in detail below with reference to the accompanying drawings. The following embodiments are only used to illustrate the technical solutions of the present application more clearly, and therefore are only examples and cannot be used to limit the protection scope 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 be the ordinary meanings understood by those skilled in the art 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", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the embodiments of the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the embodiments of the present application.

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

[0053] In the description of the embodiments of the present application, unless otherwise clearly specified or limited, technical terms such as "installation", "connection", "connection", "fixation" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can also be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to specific circumstances.

[0054] In the description of the embodiments of the present application, unless otherwise clearly specified or limited, the first feature being "on" or "under" the second feature can be that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on" the second feature can be that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is at a higher horizontal height than the second feature. The first feature being "under", "below" and "beneath" the second feature can be that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is at a lower horizontal height than the second feature.

[0055] Currently, from the perspective of the development of the market situation, the application of batteries is becoming more and more extensive. Batteries are not only used in energy storage power systems such as hydropower, thermal power, wind power and solar power stations, but also widely used in electric transportation tools such as electric bicycles, electric motorcycles and electric vehicles.

[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 embodiments of the present application, the battery cell can be a secondary battery, which refers to a battery cell that can be activated by charging after discharging to continue use.

[0058] The battery cell can include but is 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-metal hydride battery cells, nickel-cadmium battery cells, lead-acid battery cells, etc.

[0059] As an example, the battery cell can be a cylindrical battery cell, a prismatic battery cell or a battery cell of other shapes. The prismatic battery cell includes a square shell battery cell, a blade-shaped battery cell, a multi-prismatic battery, and the multi-prismatic battery is, for example, a hexagonal prism battery, etc.

[0060] In some embodiments, the battery can 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. The battery cells or battery modules are accommodated in the case.

[0062] In some embodiments, the case may be part of the chassis structure of a vehicle. For example, a part of the case may form at least a part of the floor of the vehicle, or a part of the case may form at least a part of the cross beams and longitudinal beams of the vehicle.

[0063] In some embodiments, the battery may be an energy storage device. The energy storage device includes an energy storage container, an energy storage cabinet, etc.

[0064] Generally, a battery cell includes an electrode assembly and a housing. The electrode assembly is accommodated in 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 embedded and extracted back and forth between the cathode and the anode. The separator is disposed between the cathode and the anode, which can reduce the risk of short circuit between the cathode and the anode and allow the active ions to pass through.

[0065] The housing is used to encapsulate components such as the electrode assembly and the electrolyte. 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, etc.

[0066] In some embodiments, the cathode may be a cathode sheet, and the cathode sheet 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, and the anode sheet 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 process of the electrode sheet (cathode sheet or anode sheet), it is usually necessary to perform cutting (such as the electrode sheet slitting process or the tab die-cutting process) to form the required size and shape. However, after cutting, burrs are likely to be generated at the cutting position of the current collector; during the charge and discharge process of the battery cell, the burrs may pierce the separator and conduct the cathode and the anode, leading to a short circuit risk and affecting the reliability of the battery cell.

[0068] In view of this, the embodiments of the present application provide a technical solution, which sets an insulating member on the electrode sheet to cover the end face of the current collector where burrs are likely to be generated, thereby reducing the risk of the burrs conducting the cathode and the anode 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 computer, a laptop computer, an electric toy, an electric tool, a battery car, an electric vehicle, a ship, a spacecraft, etc. Among them, the electric toy can include a fixed or mobile electric toy, for example, a game console, an electric vehicle toy, an electric ship toy, an electric aircraft toy, etc., and the spacecraft can include an airplane, a rocket, a space shuttle, a spaceship, etc.

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

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

[0073] As Figure 1 shown, a battery 2 is provided inside the vehicle 1, and the battery 2 can be provided at the bottom, head or tail of the vehicle 1. The battery 2 can be used for power supply of the vehicle 1. For example, the battery 2 can be used as an operating power source of 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, it is used for the working power requirements during the start, navigation and driving of the vehicle 1.

[0075] In some embodiments of the present application, the battery 2 can not only be used as an operating power source of the vehicle 1, but also be used as a 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 FIG. is an exploded view of the battery 2 provided in some embodiments of the present application. As Figure 2 shown, the battery 2 includes a box body 5 and battery cells (not shown), and the battery cells are accommodated in the box body 5. The battery cell can be the smallest unit that makes up the battery 2.

[0077] The housing 5 is used to accommodate battery cells, and the housing 5 can have various structures. In some embodiments, the housing 5 can include a first housing part 5a and a second housing part 5b. The first housing part 5a and the second housing part 5b cover each other, and the first housing part 5a and the second housing part 5b jointly define an accommodation space 5c for accommodating battery cells. The second housing part 5b can be a hollow structure with an open end, and the first housing part 5a is a plate-like structure. The first housing part 5a covers the open side of the second housing part 5b to form the housing 5 with the accommodation space 5c. Both the first housing part 5a and the second housing part 5b can also be hollow structures with an open side, and the open side of the first housing part 5a covers the open side of the second housing part 5b to form the housing 5 with the accommodation space 5c. Of course, the first housing part 5a and the second housing part 5b can have various shapes, such as a cylinder, a cuboid, etc.

[0078] To improve the sealing performance after the connection between the first housing part 5a and the second housing part 5b, a sealing member can also be provided between the first housing part 5a and the second housing part 5b, such as sealant, sealing ring, etc.

[0079] Assume that the first housing part 5a covers the top of the second housing part 5b. The first housing part 5a can also be called the upper cover, and the second housing part 5b can also be called the lower housing 5.

[0080] In the battery 2, there can be one or multiple battery cells. If there are multiple battery cells, they can be connected in series, parallel, or in a mixed connection. A mixed connection means that there are both series and parallel connections among multiple battery cells. Multiple battery cells can be directly connected in series, parallel, or in a mixed connection together, and then the whole formed by multiple battery cells is accommodated in the housing 5. Of course, it can also be that multiple battery cells are first connected in series, parallel, or in a mixed connection to form battery modules 6, and then multiple battery modules 6 are connected in series, parallel, or in a mixed connection to form a whole and are accommodated in the housing 5.

[0081] Multiple battery cells can be directly arranged in the housing 5 to form the battery 10, or multiple battery cells can first form battery modules 6, and then multiple battery modules 6 are arranged in the housing 5 to form the battery 10.

[0082] Figure 3 The explosion diagram of the battery module 6 provided in some embodiments of the present application.

[0083] As Figure 3 shown, in some embodiments, there are multiple battery cells 7. Multiple battery cells 7 are first connected in series, parallel, or in a mixed connection to form battery modules 6. Then multiple battery modules 6 are connected in series, parallel, or in a mixed connection to form a whole battery module 6 and are accommodated in the housing 5.

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

[0085] The battery cell 7 can be a cylindrical battery cell 7, a prismatic battery cell 7, or a battery cell 7 with other shapes.

[0086] As Figure 4 shown, in some embodiments, the battery cell 7 includes a housing 20 and an electrode assembly 30. The electrode assembly 30 is accommodated within the housing 20. Among them, the electrode assembly 30 is a cylindrical wound structure.

[0087] The housing 20 can be of various shapes and sizes, such as cuboid, 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 material of the housing 20 can be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, etc.

[0088] The electrode assembly 30 is the component in the battery cell 7 where an electrochemical reaction occurs. The housing 20 can contain one or more electrode assemblies 30.

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

[0090] The first pole piece 301 and the second pole piece 302 are two types of pole pieces with opposite electrode characteristics, one of which is an anode pole piece and the other is a cathode pole piece. The first pole piece 301 and the second pole piece 302 are wound along the winding direction X, making the electrode assembly 30 a wound structure.

[0091] The first current collector 3011 can be a structure with conductive ability, which can be formed by disposing a conductive material on an insulating substrate. Exemplarily, the conductive material on the first current collector 3011 can include metal materials, and the metal materials include aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, or silver alloy, etc. The first active material layer 3012 can be a structural layer containing polar active materials.

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

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

[0094] The first end face 30111 can be the surface of the end of the first current collector 3011 along the winding direction X, and it can be formed by cutting during the preparation of the electrode tab. Exemplarily, the first end face 30111 can 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 member with insulating properties. By connecting the first insulating member 303 to the first electrode tab 301 and covering at least part of the first end face 30111 with the first insulating member 303, the burrs at the part of the first end face 30111 covered by the first insulating member 303 are wrapped by the first insulating member 303, reducing the possibility of the burrs piercing the separator 305 and reducing the risk of short circuit in the battery cell 7.

[0096] Exemplarily, the first insulating member 303 can be an insulating structure with an opening, and the end of the first current collector 3011 having the first end face 30111 is inserted into the opening to wrap the first end face 30111; the first insulating member 303 can also be formed by curing an insulating adhesive, and the insulating adhesive covers the first end face 30111 by adhering to it; the first insulating member 303 can also be formed by adhering an insulating tape to the end of the first current collector 3011 having the first end face 30111 and wrapping 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 wrap the burrs at the first end face 30111, reducing the risk of the burrs piercing the separator 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, first insulating members 303 are provided at both ends of the first pole piece 301 along the winding direction X.

[0099] By providing first insulating members 303 at both ends of the first pole piece 301 along the winding direction X, at least a part of the first end surfaces 30111 at both ends of the first pole piece 301 along the winding direction X are covered by the first insulating members 303, so that the burrs on the first end surfaces 30111 at both ends of the first pole piece 301 can be covered, and the risk that the burrs pierce the separator 305 of the electrode assembly 30 can be further reduced, which is beneficial 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 or the first current collector 3011 of the first pole piece 301, the connection of the first insulating member 303 on the first pole piece 301 is firm and not easy to fall off. Exemplarily, the first insulating member 303 can be bonded to the first active material layer 3012 or the first current collector 3011 through 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 pole piece 301 have a larger bonding area, which is beneficial to improving the firmness of the connection of the first insulating member 303 on the first pole piece 301.

[0103] In some embodiments, the first insulating member 303 includes two relatively 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 laminated 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 can be a partial structure of the first insulating member 303. The two first insulating layers 3031 are relatively arranged and are respectively connected to two relatively arranged surfaces at the end of the first pole piece 301 for covering the first end surface 30111.

[0105] Such as Figure 7As shown, 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 arranged in sequence along the winding direction X. Among them, the first covering portion 30312 is used to connect with the first pole piece 301, and the first connecting portion 30311 is used to connect with the first connecting portion 30311 of another first insulating layer 3031 to cover the end portion of the first pole piece 301 where the first end face 30111 is located.

[0106] The first covering portions 30312 of the two first insulating members 303 are respectively laminated on both sides of the first pole piece 301 by being pasted on two opposite surfaces of the first pole piece 301, and the first connecting portions 30311 of the two first insulating layers 3031 are adhesively 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] Exemplarily, the first insulating layer 3031 can be an insulating tape. A part of the insulating tape is pasted on the surface of the first pole piece 301, and the other part is adhesively bonded and attached to another insulating tape.

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

[0109] By setting the thickness of the first pole piece 301 to H1, setting the thickness of the first insulating layer 3031 to H2, and making the thickness after the first connecting portions 30311 in the two first insulating layers 3031 are adhesively bonded less than or equal to the thickness of the first pole piece 301, it is beneficial to reduce the occurrence of steps in the wound electrode assembly 30 and reduce the possibility of cracks in the first pole piece 301 due to step stress.

[0110] In some embodiments, a first insulating member 303 is connected to the inner end of the first pole piece 301, and at least a part of the first pole piece 301 is wound outside 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 part of the first pole piece 301 outside the first insulating member 303, the first insulating member 303 at the inner end of the first pole piece 301 can be wound at the center of the electrode assembly 30, so that the first insulating member 303 can play a supporting role for the electrode assembly 30, which is beneficial to reducing the possibility of collapse of the electrode assembly 30.

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

[0113] The length A1 by which the first insulating member 303 at the inner end of the first electrode tab 301 extends beyond the first electrode tab 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 by which the first insulating member 303 connected to the inner end of the first electrode tab 301 extends beyond the first electrode tab 301 in the direction opposite to the winding direction X to be 0.5 mm ≤ A1 ≤ 120 mm, the first insulating member 303 connected to the inner end of the first electrode tab 301 can form a bobbin with good supporting ability, can better support the center of the electrode assembly 30, and can better prevent the electrode assembly 30 from collapsing.

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

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

[0116] The second electrode tab 302 is a cathode tab. The second current collector 3021 included in the second electrode tab 302 can be a structure having electrical conductivity, and it can be formed by providing a conductive material on an insulating substrate. Exemplarily, the conductive material on the second current collector 3021 can include a metal material, and the metal material includes aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver or silver alloy, etc.

[0117] The second active material layer 3022 can be a structural layer containing a cathode active material, and the cathode active material can 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 conventional materials that can be used as the cathode active material of the battery 2 can also be used. These cathode active materials can be used alone or in combination of two or more. Among them, examples of the lithium-containing phosphate can include but are not limited to lithium iron phosphate (such as LiFePO4 (which can also be abbreviated 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 the lithium transition metal oxide can 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 (which can also be abbreviated as NCM 333 )、LiNi 0.5 Co 0.2 Mn 0.3 O2 (which can also be abbreviated as NCM 523 )、LiNi 0.5 Co 0.25 Mn 0.25 O2 (which can also be abbreviated as NCM 211 )、LiNi 0.6 Co 0.2 Mn 0.2 O2 (which can also be abbreviated as NCM 622 )、LiNi 0.8 Co 0.1 Mn 0.1 O2 (which can also be abbreviated as NCM 811 )、lithium nickel cobalt aluminum oxide (such as LiNi 0.80 Co 0.15 Al 0.05 O2) and their modified compounds, etc.

[0118] The second end face 30211 can be the surface of the end of the second current collector 3021 along the winding direction X, and it can be formed by cutting during the preparation of the electrode. Exemplarily, the second end face 30211 can 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 member with insulating properties. By connecting the second insulating member 304 to the second pole piece 302 and covering at least a part of the second end face 30211 with the second insulating member 304, the burrs at the part of the second end face 30211 covered by the second insulating member 304 are covered by the second insulating member 304, reducing the possibility of the burrs piercing the separator 305 and reducing the risk of short circuit of 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 insulating glue, and the insulating glue covers the second end face 30211 by adhering to the second end face 30211; the second insulating member 304 can also be formed by adhering an 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] A separator 305 for isolating the stacked first pole piece 301 and second pole piece 302 is provided between the first pole piece 301 and the second pole piece 302, and it is stacked between the adjacent first pole piece 301 and second pole piece 302. Exemplarily, the separator 305 can be a separator membrane, and in the embodiments of the present application, any well-known porous structure separator membrane with good chemical stability and mechanical stability can be selected for the separator membrane.

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

[0123] In some embodiments, the separator 305 can also be a solid electrolyte. The solid electrolyte is provided between the first pole piece 301 and the second pole piece 302, and simultaneously functions to transport ions and isolate the first pole piece 301 and the second pole piece 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 that of the first pole piece 301, and configuring the elastic modulus of the second insulating member 304 to be greater than that 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 at 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 at the center of the electrode assembly 30, which is beneficial to reducing the possibility of the electrode assembly 30 collapsing.

[0126] Exemplarily, the elastic moduli of the first insulating member 303 and the second insulating member 304 can be Young's moduli, which can be obtained by measurement according to the national standard GB / T 1447 - 2005. The specific measurement method can refer to the national standard GB / T1447 - 2005 and will not be elaborated here.

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

[0128] Since in the electrode assembly 30 with a cylindrical winding structure, in the winding direction X, the anode pole piece usually extends beyond the cathode pole piece. By configuring the first pole piece 301 as the anode pole piece, the second pole piece 302 as the cathode pole piece, 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 pole piece can be longer than the second insulating member 304 at the center of the electrode assembly 30 and be 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, and 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 to be greater than the thickness F3 of the second insulating member in the thickness direction of the first pole piece 301, 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 a 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 disposing the first insulating member 303 inside the second insulating member 304 in the direction opposite to the winding direction X, such that the entire first insulating member 303 is located inside the second insulating member 304, not only can the anode electrode sheet extend beyond the cathode electrode sheet in the winding direction X, but also the first insulating member 303 connected to the inner end of the first electrode sheet 301 can be better wound around the center of the electrode assembly 30 and can better play a supporting role.

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

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

[0135] In some embodiments, second insulating members 304 are provided at both ends of the second electrode sheet 302 along the winding direction X.

[0136] By disposing second insulating members 304 at both ends of the second electrode sheet 302 along the winding direction X, at least a part of the second end faces 30211 at both ends of the second electrode sheet 302 along the winding direction X are covered by the second insulating members 304, such that the burrs on the second end faces 30211 at both ends of the second electrode sheet 302 can be covered, and the risk that the burrs pierce the separator 305 of the electrode assembly 30 can be further reduced, which is beneficial to further improving the reliability of the battery 2.

[0137] In some embodiments, the length by which the second insulating member 304 at the inner end of the second electrode sheet 302 extends beyond the second electrode sheet 302 is B1, and the length by which the second insulating member 304 at the outer end of the second electrode sheet 302 extends beyond the second electrode sheet 302 is B4, where B1 > B4.

[0138] By setting the length by which the second insulating member 304 at the inner end of the second electrode sheet 302 extends beyond the second electrode sheet 302 to be B1, setting the length by which the second insulating member 304 at the outer end of the second electrode sheet 302 extends beyond the second electrode sheet 302 to be B4, and making B1 > B4, while enabling the second insulating member 304 to have a good supporting effect, waste can be reduced.

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

[0140] As shown Figure 9 in the figure, the second insulating layer 3041 includes a second connecting portion 30411 and a second covering portion 30412 that are interconnected. The second connecting portion 30411 and the second covering portion 30412 are arranged in sequence along the winding direction X. Among them, the second covering portion 30412 is used to connect with the second pole piece 302, and the second connecting portion 30411 is used to connect with 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 face 30211 is located.

[0141] The second covering portions 30412 of the two second insulating members 304 are respectively laminated on both sides of the second pole piece 302 by being pasted on two opposite surfaces of the second pole piece 302. The second connecting portions 30411 of the two second insulating layers 3041 are adhesively 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 by which the second insulating member 304 at the inner end of the second pole piece 302 extends beyond 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 opposite direction of the winding direction X. The length B4 by which the second insulating member 304 at the outer end of the second pole piece 302 extends beyond 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 range of the length B1 (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) by which the second insulating member 304 at the inner end of the second pole piece 302 extends beyond the second pole piece 302 is configured to be 0.5 mm ≤ B1 ≤ 120 mm. By configuring the range of the length B1 by which the second insulating member 304 at the inner end of the second pole piece 302 extends beyond the second pole piece 302 to be 0.5 mm ≤ B1 ≤ 120 mm, 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, and will not be too long to cause waste. In some embodiments, the range of the length B1 by which the second insulating member 304 at the inner end of the second pole piece 302 extends beyond the second pole piece 302 is configured to be 1 mm ≤ B1 ≤ 100 mm, so that the second insulating member 304 at the inner end of the second pole piece 302 can better support the electrode assembly 30 without being too long to cause waste.

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

[0145] Exemplarily, the second insulating layer 3041 may be an insulating tape, and two parts of the insulating tape are adhered to the surface of the second pole piece 302, and the other part is adhesively 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, and 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 part of the first insulating member 303 covering the first pole piece 301 at the inner end of the first pole piece 301 in the winding direction X, and the length B2 of the second covering portion 30412 at the inner end of the second pole piece 302 is the length of the part of the second insulating member 304 covering the second pole piece 302 at the inner end of the second pole piece 302 in the winding direction X. By making B2 < A2, the area of the second insulating member 304 covering the second pole piece 302 at the inner end of the second pole piece 302 can be reduced, which is beneficial to reducing the capacity loss caused by the arrangement of the second insulating member 304.

[0148] Exemplarily, the range of the length A2 of the first covering portion 30312 at the inner end of the first pole piece 301 is configured to be 0.5 mm ≤ A2 ≤ 120 mm. By configuring the range of the length A2 of the first covering portion 30312 at the inner end of the first pole piece 301 to be 0.5 mm ≤ A2 ≤ 120 mm, while ensuring that the first insulating member 303 at the inner end of the first pole piece 301 has sufficient bonding area with the first pole piece 301, it is not easy to cause waste of the first pole piece 301 due to excessive bonding area. This enables 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 A2 of the first covering portion 30312 at the inner end of the first pole piece 301 is configured to be 1 mm ≤ A2 ≤ 100 mm, so that the first insulating member 303 can be firmly bonded to the first pole piece 301 without wasting the area of the first pole piece 301.

[0149] The range of the length B2 of the second covering portion 30412 at the inner end of the second pole piece 302 is configured to be 0.5 mm ≤ B2 ≤ 10 mm. By configuring the range of the length B2 of the second covering portion 30412 at the inner end of the second pole piece 302 to be 0.5 mm ≤ B2 ≤ 10 mm, while ensuring that the second insulating member 304 at the inner end of the second pole piece 302 has sufficient bonding area with the second pole piece 302, it can reduce the coverage of the second pole piece 302. This enables the second insulating member 304 to be firmly bonded to the second pole piece 302 through the second covering portion 30412 without overly covering the second pole piece 302. In some embodiments, the range of the length B2 of the second covering portion 30412 at the inner end of the second pole piece 302 is configured to be 1 mm ≤ B2 ≤ 6 mm, so that the second insulating member 304 can be firmly bonded to the second pole piece 302 without 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, while ensuring that the first insulating member 303 at the outer end of the first pole piece 301 has sufficient bonding area with the first pole piece 301, it is not easy to cause waste of the first pole piece 301 due to excessive bonding area. This enables 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, so that the first insulating member 303 can be firmly bonded to the first pole piece 301 without wasting the area of the first pole piece 301.

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

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

[0153] The cylindrical structure formed by configuring the electrode assembly 30 can be formed by winding the first pole piece 301, the second pole piece 302, and the separator 305 in the electrode assembly 30 along the winding direction X after stacking.

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

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

[0156] The first tab 3013 is subjected to a flattening process to obtain the 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 appearance of a sharp corner structure, and facilitate subsequent welding of the current collecting plate at the end of the electrode assembly 30 in the direction perpendicular to the winding direction X, ensuring the welding quality.

[0157] The fact that the flattened area 30131 is spaced apart from the first insulating member 303 may mean that the first insulating member 303 is not provided on the flattened area 30131 of the first tab 3013, so that the flattened area 30131 and the first insulating member 303 are in a separated state, and the first insulating member 303 will not affect the connection between the flattened area 30131 and the current collecting plate.

[0158] In some embodiments, such as Figure 10As shown, in the 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 tab 3013 is provided to the surface of the first tab 3013 through the first active material layer 3012, so that the first insulating member 303 can cover a larger area of the first end face 30111, which is beneficial to covering more burrs on the first end face 30111 and further reducing the risk of the burrs piercing the separator 305 of the electrode assembly 30.

[0159] Exemplarily, in the direction perpendicular to the winding direction X, the length of the first insulating member 303 extending from the first active material layer 3012 is G1, and G1 ≤ 4 mm, so that the first insulating member 303 can preferably avoid the flattening area 30131 of the first tab 3013.

[0160] As Figure 11 shown, the first insulating member 303 may not extend from the side of the first pole piece 301 where the first tab 3013 is provided, so that the first insulating member 303 can better avoid the flattening area 30131 of the first tab 3013 and is not likely to affect and change the structure of the first 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, and G2 ≤ 4 mm, so that the first insulating member 303 can cover a larger area of the first end face 30111, which is beneficial to covering more burrs on the first end face 30111 and further reducing the risk of the burrs piercing the separator 305 of the electrode assembly 30.

[0161] In some embodiments, in the direction perpendicular to the winding direction X, the first insulating member 303 can extend from the side of the first pole piece 301 away from the first tab 3013 through the first active material layer 3012, so that the first insulating member 303 can better cover the first end face 30111, which is beneficial to covering more burrs on the first end face 30111 and further reducing the risk of the burrs piercing the separator 305 of the electrode assembly 30. Exemplarily, the length of the first insulating member 303 extending from the side of the first pole piece 301 away from the first tab 3013 through the first active material layer 3012 is I1, and I1 ≤ 4 mm, which is beneficial to reducing the amount of the first insulating member 303 used and waste of materials.

[0162] Exemplarily, 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 tab 3013, and the length of the first insulating member 303 from the edge of the first active material layer 3012 is I, and I ≤ 4 mm, so that the first insulating member 303 can cover a larger area of the first end face 30111, which is beneficial to covering more burrs on the first end face 30111 and further reducing the risk of the burrs piercing the separator 305 of the electrode assembly 30.

[0163] Some embodiments of the present application further provide a battery cell 7, which includes a housing 20 and at least one electrode assembly 30 provided by the above technical solution. 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. The battery 2 is used to provide electrical energy. The electrical device can be any of the foregoing devices or systems that use the battery 2.

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

[0167] S1. Provide a plurality of first electrode plates 301 and insulating members. The first electrode plate 301 includes a first current collector 3011 and a first active material layer 3012 provided 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 face 30111.

[0168] The provided first electrode plate 301 can be the first electrode plate 301 in the foregoing technical solution, which includes a first current collector 3011 and a first active material layer 3012 provided on the surface of the first current collector 3011. Each first electrode plate 301 is used to form an electrode assembly 30. The first current collector 3011 in the first electrode plate 301 has a first end face 30111 at the end along its own length direction. The insulating member can be an insulating structure for connecting two first electrode plates 301.

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

[0170] S2. Connect two adjacent first electrode plates 301 through an insulating member, and the insulating member covers at least a part of the first end face 30111.

[0171] Through step S2, a plurality of first pole pieces 301 are sequentially connected along the length direction of the first pole piece 301 to form a long strip structure. Among them, two adjacent first pole pieces 301 are connected by an insulating member, and the insulating member covers at least part of the first end face 30111 of the first current collector 3011, realizing that the insulating member covers at least part of the burrs on the first end face 30111, and reducing the possibility of piercing the separator 305 after winding to form the electrode assembly 30.

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

[0173] Through step S2, wind the long strip structure including a plurality of first pole pieces 301 and insulating members to form a cylindrical winding structure.

[0174] S4. Cut the insulating member between two adjacent first pole pieces 301 so that first insulating members 303 are formed at both ends of the first pole piece 301 in the winding direction X, and the first insulating members 303 cover at least part of the first end face 30111.

[0175] Through the above 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 off in the middle, so that the insulating member is divided into first insulating members 303 connected to both ends of two adjacent first pole pieces 301 in the winding direction X, and the first insulating members 303 cover at least part of the first end face 30111.

[0176] According to some embodiments of the present application, embodiments of the present application provide an electrode assembly 30, which includes a first electrode tab 301, a second electrode tab 302, a separator 305, a first insulating member 303, and a second insulating member 304. The first electrode tab 301, the second electrode tab 302, and the separator 305 are stacked. The separator 305 is disposed between the first electrode tab 301 and the second electrode tab 302. The first electrode tab 301 includes a first current collector 3011 and a first active material layer 3012 disposed on the surface of the first current collector 3011. An end portion of the first current collector 3011 along the winding direction X has a first end face 30111. The first insulating member 303 is connected to the first electrode tab 301 and covers at least a part of the first end face 30111. The second electrode tab 302 includes a second current collector 3021 and a second active material layer 3022 disposed on the surface of the second current collector 3021. An end portion of the second current collector 3021 along the winding direction X has a second end face 30211. The second insulating member 304 is connected to the second electrode tab 302 and covers at least a part of the second end face 30211. Among them, the inner end of the first electrode tab 301 is connected with the first insulating member 303, and at least a part of the first electrode tab 301 is wound outside the first insulating member 303. In the above structure, since the first end face 30111 at the end of the first current collector 3011 is covered with the first insulating member 303, the first insulating member 303 can wrap the burrs at the first end face 30111, reducing the risk of the burrs piercing the separator 305 of the electrode assembly 30, reducing the possibility of a short circuit occurring inside the battery 2, and being beneficial to improving 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 foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should all be covered within the scope of the claims and the description of the present application. In particular, as long as there is no structural conflict, the technical features mentioned in each embodiment can be combined in any way. The present application is not limited to the specific embodiments disclosed in the text, but includes all technical solutions that fall within the scope of the claims.

Claims

1. An electrode assembly, comprising a first pole piece and a second pole piece with opposite polarities, the first pole piece and the second pole piece being 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 an end portion of the first current collector along the winding direction has a first end face; The electrode assembly further includes a first insulating member, the first insulating member being connected to the first pole piece and covering at least a portion of the first end face.

2. The electrode assembly according to claim 1, wherein, The first insulating members are 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 claim 1, wherein, The first insulating member includes two oppositely disposed first insulating layers, the first insulating layer includes a first connecting portion and a first covering portion, the first covering portion is laminated on the first pole piece, and 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, and H2 ≤ H1.

6. The electrode assembly according to claim 1, wherein, The inner end of the first pole piece is connected with the first insulating member, and at least a portion of the first pole piece is wound outside the first insulating member.

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

8. The electrode assembly according to claim 1, wherein, The second pole piece includes a second current collector and a second active material layer disposed on a surface of the second current collector, and an end portion of the second current collector along the winding direction has a second end face; the electrode assembly further includes a second insulating member, the second insulating member being connected to the second pole piece and covering at least a portion of the second end face.

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 in the opposite direction of the winding direction, the first insulating member extends beyond the second insulating member.

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 of the winding direction, the first insulating member is located inside the second insulating member.

13. The electrode assembly according to claim 10, 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 claim 10, wherein, The second insulating members are provided at both ends of the second pole piece along the winding direction.

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

16. The electrode assembly according to claim 1, wherein, The electrode assembly is in a cylindrical structure.

17. The electrode assembly according to claim 1, 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, and the flattened area is spaced apart from the first insulating member.

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

19. A battery, wherein, Including a battery cell according to claim 18.

20. An electrical device, wherein, Including a battery according to claim 19, the battery being used to provide electrical energy.

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