Pole piece, battery cell assembly and preparation method, battery cell, battery and power-consuming device

Abstract

The present application discloses a pole piece, a battery cell assembly and a preparation method, a battery cell, a battery and an electrical device. The pole piece is used to wind up a battery cell assembly, and the pole piece includes: a main body, extending along a first direction; a pole ear, extending from the main body along a second direction, and a plurality of pole ears are spaced and distributed along the first direction on the same side of the main body, wherein a first insulating layer is coated on the pole ear, and the first insulating layer has a height extending along the second direction, and in at least two adjacent pole ears, the height of the first insulating layer on the previous pole ear is less than the height of the first insulating layer on the next pole ear. The present application can improve the safety performance of the battery cell assembly.

Description

Technical Field

[0001] The present application relates to the field of batteries, and specifically to a pole piece, a battery cell assembly and a preparation method, a battery cell, a battery and an electrical device. Background Art

[0002] Energy conservation and emission reduction are the key to the sustainable development of the automobile industry. Electric vehicles have become an important part of the sustainable development of the automobile industry due to their advantages of energy conservation and environmental protection. For electric vehicles, battery technology is an important factor related to their development. Batteries include battery cells, which include battery cell components. As the most basic and important component of batteries, the safety performance of battery cell components directly affects the safety performance of batteries. Summary of the invention

[0003] In view of the above problems, the present application provides a pole piece, a battery cell assembly and a preparation method, a battery cell, a battery and an electrical device, which can improve the safety performance of the battery cell assembly.

[0004] In a first aspect, the present application provides a pole piece for winding to form a battery cell assembly, the pole piece comprising: a main body extending along a first direction; a pole ear extending from the main body along a second direction, wherein a plurality of pole ears are spaced apart and distributed along the first direction on the same side of the main body, wherein a first insulating layer is coated on the pole ear, the first insulating layer having a height extending along the second direction, and among at least two adjacent pole ears, the height of the first insulating layer on the previous pole ear is less than the height of the first insulating layer on the next pole ear.

[0005] In the technical solution of the embodiment of the present application, the pole piece includes a main body and a pole ear, and a first insulating layer is arranged on the pole ear, and the height of the first insulating layer on at least two adjacent pole ears is different. In the process of winding the pole piece to form a battery cell assembly, the pole ear with a higher first insulating layer height can be stacked and arranged on the inner side of other pole ears, that is, the pole ear with a higher first insulating layer height and its corresponding main body are wound to form the battery cell assembly. When the pole ear is bent to form the connecting terminal of the battery cell assembly, the pole ear with a higher first insulating layer height is close to the inner side of the connecting terminal. On the one hand, the first insulating layer can improve the structural strength of the inner pole ear, improve the problem of easy damage to the pole ear when bending to produce metal particles, and can improve the life of the pole ear and the safety performance of the battery cell assembly; on the other hand, the first insulating layer can provide support to the outer pole ear, and improve the short circuit problem caused by the outer pole ear being easily folded and inserted into the inner pole ear. Therefore, the embodiment of the present application can improve the safety performance of the battery cell assembly by setting first insulating layers of different heights on different pole ears.

[0006] In some embodiments, the tab has two surfaces arranged opposite to each other, both surfaces are coated with a first insulating layer. Two layers of first insulating layers are arranged on the tab, and the two layers of first insulating layers can provide better protection for the tab and further improve the structural strength of the tab.

[0007] In some embodiments, the pole lug has a bending area, and the pole lug is used to bend in the bending area to form a connecting terminal of the battery cell assembly. Among at least two adjacent pole lugs, the height of the first insulating layer on the first pole lug in the bending area is less than the height of the first insulating layer on the second pole lug in the bending area. The heights of the first insulating layer in the bending area of ​​different pole lugs are different. In the process of winding the pole piece to form a battery cell assembly, the pole lug with a larger first insulating layer height can be set on the inner side of the connecting terminal, and the pole lug with a smaller first insulating layer height can be set on the outer side of the connecting terminal. Since the height of the first insulating layer in the bending area of ​​the inner pole lug is higher, the inner first insulating layer can not only cover the fold line formed when the pole lug is bent, thereby improving the structural strength of the pole lug, but also provide support to the outer pole lug, thereby improving the short-circuit connection caused by the outer pole lug being bent and inserted toward the inside.

[0008] In some embodiments, the first insulating layer is coated on the area of ​​the tab adjacent to the main body, so that the first insulating layer can provide protection to the root of the tab close to the main body, avoiding the tab from being easily broken from the main body due to insufficient structural strength at the root of the tab, and improving the yield and service life of the battery cell assembly.

[0009] In some embodiments, the tab also includes a welding area located on the side of the first insulating layer away from the main body, and the spacing between the first insulating layer and the welding area in the second direction is 2mm to 6mm. By providing a welding area on the tab, the tab can be connected to other external electrical connectors through the welding area. When the spacing between the first insulating layer and the welding area is 2mm to 6mm, it can not only avoid the spacing between the first insulating layer and the welding area being too close to affect the connection between the welding area and the external electrical connector, but also avoid the spacing between the first insulating layer and the welding area being too far to cause material waste, and make the tab too long and more susceptible to damage.

[0010] In some embodiments, the tab has a first edge facing away from the main body, and the distance between the welding area and the first edge is 1 mm to 3 mm. A gap is left on the side of the welding area facing away from the first insulating layer, which can leave enough space for connecting the welding area with an external electrical connector.

[0011] In some embodiments, a second insulating layer is coated on the main body, the second insulating layer is located on the side of the main body facing the tab, and the second insulating layer is connected to the first insulating layer. Providing the second insulating layer on the main body can provide protection for the connection between the tab and the main body, and improve the poor connection between the tab and the main body.

[0012] In some embodiments, the height of the second insulating layer in the second direction is 2 mm to 4 mm. When the height of the second insulating layer is within the above range, it can prevent the height of the second insulating layer from being too small to provide good protection for the connection between the tab and the main body, and it can also prevent the height of the second insulating layer from being too large to affect the coating of the active material on the main body and the energy density of the battery cell assembly.

[0013] In some embodiments, the body includes a second edge between two adjacent tabs, and the maximum spacing between the first insulating layer and the second edge in the second direction is greater than or equal to 1 mm. The height of the first insulating layer is ensured to be sufficient so that at least part of the height of the first insulating layer can extend to the bending position after the tab is bent.

[0014] In some embodiments, one or more tabs form multiple tab groups, and in two adjacent tab groups along the first direction, the height of the first insulating layer in the previous tab group is less than the height of the first insulating layer in the next tab group. When winding to form a cell assembly, the tab group with a larger first insulating layer height can be arranged on the inner side of the electrode terminal, and the tab group with a smaller first insulating layer height can be arranged on the outer side of the electrode terminal, which can not only improve the structural strength of the previous tab group, and improve the problem that the tabs in the previous tab group are easily damaged by bending, but also enable the tabs in the previous tab group to provide support to the tabs in the next tab group, and improve the problem that the next tab group is easily deformed and inserted into the previous tab group.

[0015] In some embodiments, the first insulating layers on the tabs in the same tab group have the same height, which can reduce the difficulty of tab preparation, simplify the tab preparation process, and improve tab preparation efficiency.

[0016] In the second aspect, the present application provides a battery cell assembly, which includes the pole piece in the above-mentioned embodiment, and the battery cell assembly includes a main body formed by winding a main body and a connecting terminal which is stacked by multiple pole ears and extends along a preset bending path, wherein a first section and a second section of the pole ears are intersectingly arranged and an angle area between the first section and the second section, in at least two adjacent layers of pole ears, the length of the first insulating layer on the pole ear away from the angle area is less than the length of the first insulating layer on the pole ear close to the angle area.

[0017] In some embodiments, the pole ear has a bending area, and the pole ear is used to bend in the bending area to form a connecting terminal of the battery cell assembly. Among at least two adjacent pole ears, the length of the first insulating layer on the previous pole ear in the bending area is smaller than the length of the first insulating layer on the next pole ear in the bending area.

[0018] In some embodiments, the second section is located on a side of the first section facing away from the main body;

[0019] The first insulating layer on at least one pole lug close to the angle region extends from the first section to the second section; and / or the first insulating layer on at least one pole lug away from the angle region is located in the first section.

[0020] In a third aspect, the present application provides a battery cell comprising the battery cell assembly of the above embodiment.

[0021] In a fourth aspect, an embodiment of the present application provides a battery, which includes the battery cell of the above embodiment.

[0022] In a fifth aspect, the present application provides an electrical device, which includes the battery in the above embodiment, and the battery is used to provide electrical energy.

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

[0024] Provided is a pole piece, comprising a main body extending along a first direction and a pole ear extending from the main body along a second direction, wherein a plurality of pole ears are spaced and distributed along the second direction on the same side of the main body;

[0025] A first insulating layer is coated on the area of ​​the electrode tab adjacent to the main body, and in at least two electrode tabs adjacent to each other along the first direction, an extension height of the first insulating layer on the first electrode tab in the second direction is smaller than an extension height of the first insulating layer on the second electrode tab;

[0026] The pole sheets are wound to form a battery cell assembly, which includes a main body formed by winding a main body and a connecting terminal which is stacked by a plurality of pole ears and extends along a preset bending path. The pole ears are bent to form an angle area. In at least two adjacent layers of pole ears, the length of the first insulating layer on the pole ear away from the angle area is less than the length of the first insulating layer on the pole ear close to the angle area.

[0027] The present application sets first insulating layers of different heights on the tabs, so that the first insulating layers can not only improve the structural strength of the inner tabs, but also provide support to the outer tabs, thereby improving the short circuit problem caused by the outer tabs being easily folded and inserted into the inner tabs. Therefore, the embodiments of the present application can improve the safety performance of the battery cell assembly by setting first insulating layers of different heights on different tabs.

[0028] 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

[0029] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present application. Moreover, the same reference numerals are used throughout the drawings to represent the same components. In the drawings:

[0030] Figure 1 A schematic diagram of the structure of a vehicle according to some embodiments of the present application;

[0031] Figure 2 A schematic diagram of the exploded structure of a battery according to some embodiments of the present application;

[0032] Figure 3 A schematic diagram of the exploded structure of a battery cell according to some embodiments of the present application;

[0033] Figure 4 This is a schematic diagram of the structure of the pole piece of some embodiments of the present application;

[0034] Figure 5 It is a cross-sectional schematic diagram of the connection terminal of the battery cell assembly of some embodiments of the present application, showing the shape of the connection terminal formed by stacking the tabs;

[0035] Figure 6 Schematic diagrams of the structures of pole pieces of other embodiments of the present application;

[0036] Figure 7 Schematic diagrams of the structures of pole pieces of some other embodiments of the present application;

[0037] Figure 8 It is a schematic flow chart of a method for preparing a battery cell assembly provided in an embodiment of the present application.

[0038] The reference numerals in the specific implementation manner are as follows:

[0039] Vehicles 1000;

[0040] Battery 100, controller 200, motor 300;

[0041] Box body 10, first part 11, second part 12;

[0042] Battery cell 20, end cap 21, electrode terminal 21a, shell 22, battery cell assembly 23, body 231, connection terminal 232;

[0043] Pole piece 30, main body 31, second insulating layer 311, second edge 312, pole ear 32, first insulating layer 321, bending area 322, welding area 323, first edge 324, first section 325, second section 326;

[0044] Adapter 40. DETAILED DESCRIPTION

[0045] The following embodiments of the technical solution of the present application will be described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0046] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0047] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0048] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0049] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of the associated objects, indicating that there may be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0050] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[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, which 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 referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the embodiments of the present application.

[0052] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. 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 the specific circumstances.

[0053] At present, from the perspective of market development, the application of power batteries is becoming more and more extensive. Power 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 vehicles such as electric bicycles, electric motorcycles, electric cars, as well as military equipment and aerospace and other fields. With the continuous expansion of the application field of power batteries, the market demand is also constantly expanding.

[0054] The battery includes a battery cell, and the battery cell assembly of the battery cell is formed by winding the pole pieces. As the most basic and important component of the battery, the safety performance of the battery cell assembly directly affects the safety performance of the entire battery. The battery cell assembly is formed by winding the positive pole piece, the negative pole piece and the diaphragm, and the diaphragm is used to ensure the insulation of the positive pole piece and the negative pole piece. Both the positive pole piece and the negative pole piece include a main body and a pole ear extending from the main body. The main body is wound to form the main body of the battery cell assembly, and a plurality of pole ears are stacked to form the connecting terminal of the battery cell assembly. The connecting terminal is usually formed by bending the stacked pole ears.

[0055] The inventors noticed that among the multiple stacked and bent tabs, the tabs on the inner side of the connection terminal have a smaller bending angle, that is, the inner tabs have a smaller bending angle, so the tabs on the inner side of the connection terminal are more likely to be bent and damaged, or even broken. The tabs on the outer side of the connection terminal may bend toward the inner tabs due to insufficient support force and may be inserted into the inner tabs, that is, the outer tabs may be inserted into the inner tabs, resulting in the positive and negative tabs inside the battery cell assembly overlapping to form an internal short circuit.

[0056] In order to solve the problems of deformation of the pole lug and short-circuit connection of the pole lug, the applicant has found that an insulating layer can be coated on the pole lug, and the insulating layer on the inner pole lug can extend to the bending corner of the pole lug. The insulating layer can not only improve the structural strength of the inner pole lug and avoid damage to the inner pole lug, but also provide support to the outer pole lug to prevent the outer pole lug from being inserted into the inner pole lug, causing a short circuit between the positive and negative pole sheets.

[0057] Based on the above considerations, in order to solve the problem of short-circuit connection between the positive and negative electrodes in the battery cell assembly caused by the insertion of the electrode tabs, the inventors have designed a electrode sheet after in-depth research. Different electrode tabs of the electrode sheet have first insulating layers of different heights. In the process of winding the electrode sheet to form a battery cell assembly, the electrode tab with a higher first insulating layer can be stacked on the inner side of the electrode terminal, and the electrode tab with a lower first insulating layer can be stacked on the outer side of the electrode terminal. The first insulating layer on the inner electrode tab provides support to the outer electrode tab to avoid the short-circuit connection between the positive and negative electrodes caused by the insertion of the electrode tab into the inner electrode tab.

[0058] The cell assembly formed by winding the pole pieces disclosed in the embodiment of the present application can be used in, but not limited to, electric devices such as vehicles, ships or aircraft. A power supply system comprising the cell assembly, battery cells, batteries, etc. disclosed in the present application can be used to form the electric device, which is conducive to improving the safety performance of the battery.

[0059] The embodiment of the present application provides an electric device using a battery as a power source, and the electric device may be, but is not limited to, a mobile phone, a tablet, a laptop, an electric toy, an electric tool, a battery car, an electric car, a ship, a spacecraft, etc. Among them, the electric toy may include a fixed or mobile electric toy, such as a game console, an electric car toy, an electric ship toy, and an electric airplane toy, etc., and the spacecraft may include an airplane, a rocket, a space shuttle, and a spacecraft, etc.

[0060] For the convenience of description, the following embodiments are described by taking a vehicle 1000 as an example of an electrical device according to an embodiment of the present application.

[0061] Please refer to Figure 1 , Figure 1A schematic diagram of the structure of a vehicle 1000 provided for some embodiments of the present application. The vehicle 1000 may be a fuel vehicle, a gas vehicle or a new energy vehicle, and the new energy vehicle may be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc. A battery 100 is provided inside the vehicle 1000, and the battery 100 may be provided at the bottom, head or tail of the vehicle 1000. The battery 100 may be used to power the vehicle 1000, for example, the battery 100 may be used as an operating power source for the vehicle 1000. The vehicle 1000 may also include a controller 200 and a motor 300, and the controller 200 is used to control the battery 100 to power the motor 300, for example, for starting, navigating and driving the vehicle 1000.

[0062] In some embodiments of the present application, the battery 100 can not only serve as an operating power source for the vehicle 1000, but also serve as a driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0063] Please refer to Figure 2 , Figure 2 An exploded view of a battery 100 provided in some embodiments of the present application. The battery 100 includes a box 10 and a battery cell 20, and the battery cell 20 is contained in the box 10. Among them, the box 10 is used to provide a storage space for the battery cell 20, and the box 10 can adopt a variety of structures. In some embodiments, the box 10 may include a first part 11 and a second part 12, the first part 11 and the second part 12 cover each other, and the first part 11 and the second part 12 jointly define a storage space for accommodating the battery cell 20. The second part 12 may be a hollow structure with one end open, the first part 11 may be a plate-like structure, and the first part 11 covers the open side of the second part 12, so that the first part 11 and the second part 12 jointly define a storage space; the first part 11 and the second part 12 may also be hollow structures with one side open, and the open side of the first part 11 covers the open side of the second part 12. Of course, the box 10 formed by the first part 11 and the second part 12 may be in a variety of shapes, such as a cylinder, a cuboid, etc.

[0064] In the battery 100, there may be multiple battery cells 20, and the multiple battery cells 20 may be connected in series, in parallel, or in a mixed connection. A mixed connection means that the multiple battery cells 20 are both connected in series and in parallel. The multiple battery cells 20 may be directly connected in series, in parallel, or in a mixed connection, and then the whole formed by the multiple battery cells 20 is accommodated in the box 10; of course, the battery 100 may also be a battery module formed by connecting multiple battery cells 20 in series, in parallel, or in a mixed connection, and then the multiple battery modules are connected in series, in parallel, or in a mixed connection to form a whole, and accommodated in the box 10. The battery 100 may also include other structures, for example, the battery 100 may also include a busbar component for realizing electrical connection between the multiple battery cells 20.

[0065] Each battery cell 20 may be a secondary battery or a primary battery, or a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery, but is not limited thereto. The battery cell 20 may be cylindrical, flat, rectangular, or in other shapes.

[0066] Please refer to Figure 3 , Figure 3 The schematic diagram of the exploded structure of the battery cell 20 provided in some embodiments of the present application. The battery cell 20 refers to the smallest unit that constitutes the battery. Figure 3 The battery cell 20 includes an end cover 21, a shell 22, a battery cell assembly 23 and other functional components.

[0067] The end cap 21 refers to a component that covers the opening of the shell 22 to isolate the internal environment of the battery cell 20 from the external environment. Without limitation, the shape of the end cap 21 can be adapted to the shape of the shell 22 to match the shell 22. Optionally, the end cap 21 can be made of a material with a certain hardness and strength (such as aluminum alloy), so that the end cap 21 is not easily deformed when squeezed and collided, so that the battery cell 20 can have a higher structural strength and the safety performance can also be improved. Functional components such as electrode terminals 21a can be provided on the end cap 21. The electrode terminal 21a can be used to electrically connect to the battery cell assembly 23 for outputting or inputting electrical energy of the battery cell 20. In some embodiments, the end cap 21 can also be provided with a pressure relief mechanism for releasing the internal pressure when the internal pressure or temperature of the battery cell 20 reaches a threshold. The material of the end cap 21 can also be a variety of materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and the embodiments of the present application do not impose special restrictions on this. In some embodiments, an insulating member may be provided inside the end cap 21, and the insulating member may be used to isolate the electrical connection components in the housing 22 from the end cap 21 to reduce the risk of short circuit. For example, the insulating member may be plastic, rubber, or the like.

[0068] The shell 22 is a component used to cooperate with the end cover 21 to form the internal environment of the battery cell 20, wherein the formed internal environment can be used to accommodate the battery cell assembly 23, electrolyte and other components. The shell 22 and the end cover 21 can be independent components, and an opening can be set on the shell 22, and the internal environment of the battery cell 20 is formed by covering the opening with the end cover 21 at the opening. Without limitation, the end cover 21 and the shell 22 can also be integrated. Specifically, the end cover 21 and the shell 22 can form a common connection surface before other components are put into the shell, and when the interior of the shell 22 needs to be encapsulated, the end cover 21 covers the shell 22. The shell 22 can be of various shapes and sizes, such as a rectangular parallelepiped, a cylindrical shape, a hexagonal prism, etc. Specifically, the shape of the shell 22 can be determined according to the specific shape and size of the battery cell assembly 23. The material of the shell 22 can be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and the embodiment of the present application does not impose any special restrictions on this.

[0069] The cell assembly 23 is a component in the battery cell 100 where electrochemical reactions occur. One or more cell assemblies 23 may be included in the housing 22. The cell assembly 23 is mainly formed by winding or stacking positive and negative electrodes, and a separator is usually provided between the positive and negative electrodes. The cell assembly 23 includes a body 231 and a connection terminal 232. The parts of the positive and negative electrodes with active materials constitute the body 231 of the cell assembly, and the parts of the positive and negative electrodes without active materials each constitute a connection terminal 232. The positive connection terminal 232 and the negative connection terminal 232 may be located together at one end of the body 231 or at both ends of the body 231, respectively. During the charge and discharge process of the battery, the positive active material and the negative active material react with the electrolyte, and the connection terminal 232 connects to an external electrical connector to form a current loop.

[0070] According to some embodiments of the present application, referring to Figure 3 , and please refer to Figure 4 , Figure 4 Schematic diagram of the structure of the pole piece 30 according to some embodiments of the present application.

[0071] like Figure 3 and Figure 4 As shown, the present application provides a pole piece 30, which is used to be wound to form the above-mentioned battery cell assembly 23, and the pole piece 30 includes: a main body 31, which is extended along the first direction; a pole ear 32, which extends from the main body 31 along the second direction, and a plurality of pole ears 32 are distributed at intervals along the first direction on the same side of the main body 31, wherein the pole ear 32 is coated with a first insulating layer 321, and the first insulating layer 321 has a height extending along the second direction, and in at least two adjacent pole ears 32, the height of the first insulating layer 321 on the previous pole ear 32 is less than the height of the first insulating layer 321 on the next pole ear 32.

[0072] like Figure 4 As shown in , the first direction is the X direction, and the second direction is the Y direction. Optionally, the main body 31 and the tabs 32 are integrally formed, and the tabs 32 can be formed by cutting excess material between two adjacent tabs 32 .

[0073] Optionally, when the electrode sheet 30 is wound to form the cell assembly 23, the main body 31 is wound to form the main body 231 of the cell assembly 23, and the tabs 32 are stacked and bent to form the connection terminals 232. At least one of the positive electrode sheet and the negative electrode sheet of the cell assembly 23 can be selected from the electrode sheet 30 provided in the embodiment of the present application.

[0074] In the technical solution of the embodiment of the present application, the pole piece 30 includes a main body 31 and a pole ear 32, and a first insulating layer 321 is provided on the pole ear 32, and the height of the first insulating layer 321 on at least two adjacent pole ears 32 is different. In the process of winding the pole piece 30 to form the battery cell assembly 23, the pole ear 32 with a higher first insulating layer 321 can be stacked on the inner side of other pole ears 32, that is, the battery cell assembly 23 is formed by winding from the pole ear 32 with a higher first insulating layer 321 and its corresponding main body 31. When the pole ear 32 is bent to form the connecting terminal 232 of the battery cell assembly 23, the pole ear 32 with a higher first insulating layer 321 is close to the inner side of the connecting terminal 232. On the one hand, the first insulating layer 321 can improve the structural strength of the inner tab 32, improve the problem of the tab 32 being easily damaged and producing metal particles when being bent, and improve the life of the tab 32 and the safety performance of the battery cell assembly 23; on the other hand, the first insulating layer 321 can provide support to the outer tab 32, and improve the short circuit problem caused by the outer tab 32 being easily folded and inserted into the inner tab 32. Therefore, the embodiment of the present application can improve the safety performance of the battery cell assembly 23 by providing the first insulating layer 321 of different heights on different tabs 32.

[0075] See also Figure 5 , Figure 5 yes Figure 3 A partial cross-sectional view of the connection terminal 232 of the middle cell assembly 23.

[0076] like Figure 5 As shown, when the pole ear 32 is bent to form the connection terminal 232, the pole ear 32 includes a first section 325 and a second section 326 intersecting each other, and an angle region a is formed between the first section 325 and the second section 326 at an acute angle. The inner side of the connection terminal 232 refers to the side close to the angle region a, the inner pole ear 32 is the pole ear 32 close to the angle region a, and the outer side of the inner pole ear 32 has at least one layer of pole ear 32; the outer side of the connection terminal 232 refers to the side away from the angle region a, the outer pole ear 32 is the pole ear 32 away from the angle region a, and the inner side of the outer pole ear 32 has at least one layer of pole ear 32.

[0077] In the embodiment of the present application, the first insulating layer 321 on the pole ear 32 located on the inner side of the connecting terminal 232 is relatively high, so the first insulating layer 321 on the pole ear 32 located on the inner side of the connecting terminal 232 can provide support to the outer pole ear 32, preventing the outer pole ear 32 from bending inward and inserting into the inner pole ear 32, thereby improving the safety performance of the battery cell assembly 23.

[0078] like Figure 5 As shown, after the tab 32 is bent to form the connecting terminal 232 , the connecting terminal 232 and an external electrical connector such as a transfer plate 40 are welded and connected to each other.

[0079] According to some embodiments of the present application, the tab 32 may have two surfaces disposed opposite to each other. A first insulating layer 321 may be disposed on one of the two surfaces. For example, when the tabs 32 are stacked to form the connection terminal 232, the surface of the inner tab 32 facing the outer tab 32 may be provided with the first insulating layer 321 to improve the problem of the outer tab 32 being inserted into the inner tab 32. Alternatively, the surface of the inner tab 32 facing away from the outer tab 32 may be provided with the first insulating layer 321 to improve the structural strength of the tab 32.

[0080] According to some embodiments of the present application, optionally, both surfaces are coated with a first insulating layer 321. Two first insulating layers 321 are provided on the tab 32, and the two first insulating layers 321 can provide better protection for the tab 32 and further improve the structural strength of the tab 32.

[0081] See also Figure 6 , Figure 6 It is a schematic structural diagram of a pole piece 30 provided in another embodiment of the present application.

[0082] According to some embodiments of the present application, optionally, refer to Figure 5 and Figure 6 The pole ear 32 has a bending area 322, and the pole ear 32 is used to bend in the bending area 322 to form a connecting terminal 232 of the battery cell assembly 23. In at least two adjacent pole ears 32, the height of the first insulating layer 321 on the previous pole ear 32 in the bending area 322 is less than the height of the first insulating layer 321 on the next pole ear 32 in the bending area 322.

[0083] The tab 32 is bent in its bending area 322 to form the connection terminal 232. The bending area 322 of the tab 32 may be the area where the fold line is located when the tab 32 is bent, or the bending area 322 of the tab 32 may be the fold line and the area near the fold line when the tab 32 is bent. The fold line is the area near the connection position of the first section 325 and the second section 326.

[0084] Different pole tabs 32 have different heights of the first insulating layer 321 in the bending region 322. In the process of winding the pole piece 30 to form the battery cell assembly 23, the pole tab 32 with a larger height of the first insulating layer 321 can be arranged on the inner side of the connection terminal 232, and the pole tab 32 with a smaller height of the first insulating layer 321 can be arranged on the outer side of the connection terminal 232. Since the height of the first insulating layer 321 in the bending region 322 of the inner pole tab 32 is higher, the inner first insulating layer 321 can not only cover the fold line formed when the pole tab 32 is bent, thereby improving the structural strength of the pole tab 32, but also provide support to the outer pole tab 32, thereby improving the short-circuit connection caused by the outer pole tab 32 being bent and inserted toward the inner side.

[0085] See also Figure 7 , Figure 7 It is a schematic structural diagram of a pole piece 30 provided in yet another embodiment of the present application.

[0086] According to some embodiments of the present application, optionally, Figures 3 to 7 As shown, the tab 32 further includes a welding area 323 located on a side of the first insulating layer 321 away from the main body 31 , and a distance between the first insulating layer 321 and the welding area 323 in the second direction is 2 mm to 6 mm.

[0087] The welding area 323 is a connection portion between the pole tab 32 and an external electrical connector, such as the adapter 40 . The pole tab 32 is connected to the adapter 40 in the welding area 323 .

[0088] By setting the welding area 323 on the tab 32, the tab 32 can be connected to other external electrical connectors through the welding area 323. When the spacing between the first insulating layer 321 and the welding area 323 is 2 mm to 6 mm, it can prevent the spacing between the first insulating layer 321 and the welding area 323 from being too close to affect the connection between the welding area 323 and the external electrical connector, and it can also prevent the spacing between the first insulating layer 321 and the welding area 323 from being too far to cause material waste, and make the tab 32 too long and more susceptible to damage.

[0089] According to some embodiments of the present application, optionally, the tab 32 has a first edge 324 on a side away from the main body 31 , and a distance between the welding area 323 and the first edge 324 is 1 mm to 3 mm.

[0090] Optionally, the first edge 324 is arranged parallel to the second edge 312 of the main body 31. The first edge 324 is extended along the first direction. The distance between the welding area 323 and the first edge 324 is the distance between the welding area 323 and the first edge 324 in the second direction.

[0091] A gap is left on the side of the welding area 323 away from the first insulating layer 321 , so as to leave enough space for the connection between the welding area 323 and an external electrical connector.

[0092] According to some embodiments of the present application, optionally, please continue to refer to Figure 7 The first insulating layer 321 is coated on the area of ​​the tab 32 adjacent to the main body 31 .

[0093] “The area on the pole lug 32 adjacent to the main body 31” refers to the area on the pole lug 32 close to the main body 31, and the first insulating layer 321 extends from the portion where the pole lug 32 is connected to the main body 31 toward the pole lug 32 along the second direction. For example, the main body 31 has a second edge 312 located between two adjacent pole lugs 32, and the pole lug 32 has a first edge 324 away from the main body 31. The starting position of the area on the pole lug 32 adjacent to the main body 31 is located in the same straight line as the second edge 312, and extends from the straight line toward the first edge 324.

[0094] In these embodiments, the first insulating layer 321 is formed by extending from the portion where the pole lug 32 and the main body 31 are connected toward the pole lug 32, so that the first insulating layer 321 can provide protection to the root of the pole lug 32 close to the main body 31, thereby preventing the pole lug 32 from being easily broken from the main body 31 due to insufficient structural strength at the root of the pole lug 32, thereby improving the yield and service life of the battery cell assembly 23.

[0095] According to some embodiments of the present application, optionally, a second insulating layer 311 is coated on the main body 31 , the second insulating layer 311 is located on a side of the main body 31 facing the tab 32 , and the second insulating layer 311 is connected to the first insulating layer 321 .

[0096] There are many ways to connect the second insulating layer 311 and the first insulating layer 321. For example, the first insulating layer 321 can cover a portion of the second insulating layer 311 close to the pole ear 32, or the second insulating layer 311 can cover at least a portion of the first insulating layer 321 close to the main body 31, or the first insulating layer 321 and the second insulating layer 311 can be connected to each other, and the first insulating layer 321 and the second insulating layer 311 can be coated and formed in the same process step.

[0097] The second insulating layer 311 is provided on the main body 31 to provide protection for the connection between the tab 32 and the main body 31 and improve the poor connection between the tab 32 and the main body 31. The second insulating layer 311 can also improve the problem of curling around the second edge 311 when the pole piece 30 is cut.

[0098] Optionally, when a first insulating layer 321 is disposed on one surface of the pole lug 32 , a second insulating layer 311 is disposed on the corresponding surface of the body 31 , that is, the first insulating layer 321 and the second insulating layer 311 are located on the same surface of the pole piece 30 .

[0099] Optionally, two opposite surfaces of the tab 32 are both provided with a first insulating layer 321 , and two opposite surfaces of the body 31 are also both provided with a second insulating layer 311 .

[0100] According to some embodiments of the present application, optionally, a height of the second insulating layer 311 in the second direction is 2 mm to 4 mm.

[0101] When the height of the second insulating layer 311 is within the above range, it can prevent the height of the second insulating layer 311 from being too small and failing to provide better protection for the connection between the tab 32 and the main body 31 , and it can also prevent the height of the second insulating layer 311 from being too large and affecting the coating of the active material on the main body 31 and affecting the energy density of the battery cell assembly 23 .

[0102] According to some embodiments of the present application, optionally, the main body 31 includes a second edge 312 located between two adjacent tabs 32 , and a maximum distance between the first insulating layer 321 and the second edge 312 in the second direction is greater than or equal to 1 mm.

[0103] The height of the first insulating layer 321 is ensured to be sufficient, so that at least a portion of the first insulating layer 321 can extend to the bending position of the tab 32 .

[0104] According to some embodiments of the present application, optionally, the main body 31 includes a second edge 312 located between two adjacent tabs 32 , and a minimum spacing between the first insulating layer 321 and the second edge 312 in the second direction is greater than or equal to 1 mm.

[0105] When the minimum spacing between the first insulating layer 321 and the second edge 312 in the second direction is greater than or equal to 1 mm, that is, the minimum spacing between the first insulating layer 321 in the second direction is greater than or equal to 1 mm, the height of the first insulating layer 321 is ensured to be sufficient so that at least part of the height of the first insulating layer 321 can extend to the point formed when the tab 32 is bent.

[0106] According to some embodiments of the present application, optionally, one or more tabs 32 form multiple tab groups, and in two adjacent tab groups along the first direction, the height of the first insulating layer 321 in the first tab group is less than the height of the first insulating layer 321 in the second tab group.

[0107] A tab group refers to a group formed by one or more adjacent tabs 32. For example, there may be one tab 32 in a tab group, and then two tab groups adjacent along the first direction are two tabs 32 adjacent along the first direction. A tab group may also include more than two tabs 32 adjacent along the first direction.

[0108] When winding to form the battery cell assembly 23, the pole lug group with a larger first insulating layer 321 height can be set on the inner side of the electrode terminal, and the pole lug group with a smaller first insulating layer 321 height can be set on the outer side of the electrode terminal. This can not only improve the structural strength of the previous group of pole lug groups and improve the problem that the pole lugs 32 in the previous group of pole lug groups are easily damaged by bending, but also enable the pole lugs 32 in the previous group of pole lug groups to provide support to the pole lugs 32 in the next group of pole lug groups, thereby improving the problem that the next group of pole lugs 32 are easily deformed and inserted into the previous group of pole lugs 32.

[0109] According to some embodiments of the present application, optionally, the main body 31 includes a first end and a second end opposite to each other in a first direction, and in the direction from the first end to the second end, the height of the first insulating layer 321 on the pole tab 32 in the previous pole tab group is greater than the height of the first insulating layer 321 on the pole tab 32 in the next pole tab group, that is, the height of the first insulating layer 321 on the pole tab 32 in the pole tab group gradually increases in a gradient. When the pole piece 30 is wound to form the battery cell assembly 23, the winding can be started from the first end of the main body 31, so that the first end is wound inside the second end.

[0110] According to some embodiments of the present application, optionally, the first insulating layer 321 on the tabs 32 in the same tab group has the same height, which can reduce the difficulty of preparing the tabs 32 , simplify the preparation process of the tabs 32 , and improve the preparation efficiency of the tabs 32 .

[0111] Optional, Figure 4 , Figure 6 and Figure 7 The pole piece 30 shown schematically shows three pole tabs 32 on the main body 31 . The embodiment of the present application does not limit the number of the pole tabs 32 , as long as the number of the pole tabs 32 is two or more.

[0112] According to some embodiments of the present application, the present application further provides a battery cell assembly 23, and the battery cell assembly 23 includes the pole piece 30 in the above embodiment.

[0113] According to some embodiments of the present application, optionally, the battery cell assembly 23 includes a main body portion 231 formed by winding a main body 31 and a connecting terminal 232 which is stacked by a plurality of pole tabs 32 and extends along a preset bending path, wherein the pole tabs 32 have a first section 325 and a second section 326 at which they intersect and an angle region a between the first section 325 and the second section 326, and in at least two adjacent layers of the pole tabs 32, a length of the first insulating layer 321 on the pole tab 32 away from the angle region a is less than a length of the first insulating layer 321 on the pole tab 32 close to the angle region a.

[0114] The tab 32 away from the angle region a is the tab 32 located outside the connection terminal 232, i.e., the outer tab 32. The tab 32 away from the angle region a is provided with at least one layer of tabs 32 on the side facing the angle region a. The tab 32 close to the angle region a is the tab 32 located inside the connection terminal 232, i.e., the inner tab 32. The tab 32 close to the angle region a is provided with at least one layer of tabs 32 on the side away from the angle region a.

[0115] The pole tab 32 is bent along the bending path to form an electrode terminal. The length of the first insulating layer 321 is the extension length of the first insulating layer 321 along the bending path. The length value of the first insulating layer 321 is equal to the height value of the first insulating layer 321. The difference between the length of the first insulating layer 321 and the height of the first insulating layer 321 is that the length of the first insulating layer 321 refers to the extension length of the first insulating layer 321 on the bending path after the pole tab 32 is bent along the bending path. The height of the first insulating layer 321 refers to the extension height of the first insulating layer 321 in the second direction before the pole tab 32 is bent.

[0116] In these embodiments, in at least two adjacent layers of pole ears 32, the length of the first insulating layer 321 on the inner pole ear 32 is longer, and the first insulating layer 321 can provide better protection for the inner pole ear 32, and improve the problem of easy damage caused by the small bending angle of the inner pole ear 32. And by providing a longer first insulating layer 321 on the inner pole ear 32, the structural strength of the inner pole ear 32 can be improved, and the supporting effect of the inner pole ear 32 on the outer pole ear 32 can be improved, and the problem of the outer pole ear 32 being bent and deformed and easily inserted into the inner pole ear 32 to cause a short circuit can be improved.

[0117] According to some embodiments of the present application, optionally, one or more tabs 32 form multiple tab groups, and in two adjacent tab groups, the length of the first insulating layer 321 in the tab group close to the angle region a is less than the length of the first insulating layer 321 in the tab group close to the angle region a. The first insulating layer 321 on the tab 32 in the inner tab group is longer, and the first insulating layer 321 can provide better protection for the tab 32 in the inner tab group. And by providing a longer first insulating layer 321 on the inner tab 32, the structural strength of the tab 32 in the inner tab group can be improved.

[0118] According to some embodiments of the present application, optionally, along the stacking direction of the pole tabs 32, in any two adjacent pole tab groups, the length of the first insulating layer 321 in the pole tab group close to the angle region a is less than the length of the first insulating layer 321 in the pole tab group close to the angle region a. That is, the length of the first insulating layer 321 on the plurality of pole tab groups increases in a gradient along the stacking direction, and the length of the first insulating layer 321 in the pole tab group close to the angle region a is larger, which can further improve the structural strength of the inner pole tab 32 and improve the support capability provided by the inner pole tab 32 to the outer pole tab 32.

[0119] For example, the innermost tab 32 has to support multiple outer tabs 32, and the innermost tab 32 has the smallest bending angle, so the requirements for the structural strength and the supporting capacity of the innermost tab 32 are higher. In this embodiment, the length of the first insulating layer 321 on the innermost tab 32 is the longest, which can ensure that the innermost tab 32 has sufficient structural strength.

[0120] According to some embodiments of the present application, optionally, the pole lug 32 has a bending area 322, and the pole lug 32 is used to bend in the bending area 322 to form a connecting terminal 232 of the battery cell assembly 23. Among at least two adjacent pole lugs 32, the length of the first insulating layer 321 on the pole lug 32 away from the angle area a in the bending area 322 is smaller than the length of the first insulating layer 321 on the pole lug 32 close to the angle area a in the bending area 322.

[0121] Different tabs 32 have different heights of the first insulating layer 321 in the bending region 322, and the tab 32 with a longer first insulating layer 321 is arranged on the inner side of the connection terminal 232, while the tab 32 with a shorter first insulating layer 321 is arranged on the outer side of the connection terminal 232. Since the first insulating layer 321 in the bending region 322 of the inner tab 32 is longer, the inner first insulating layer 321 can not only cover the fold line formed when the tab 32 is bent, thereby improving the structural strength of the tab 32, but also provide support to the outer tab 32, thereby improving the short circuit connection caused by the outer tab 32 being bent and inserted toward the inner side.

[0122] According to some embodiments of the present application, optionally, the second section 326 is located on a side of the first section 325 away from the main body 231, and the first insulating layer 321 on at least one of the tabs 32 near the angle region a extends from the first section 325 to the second section 326. The first insulating layer 321 on the inner tab 32 can cover the bending region 322 of the tab 32, thereby improving the structural strength and support strength of the inner tab 32.

[0123] According to some embodiments of the present application, optionally, the first insulating layer 321 on at least one of the tabs 32 away from the angle region a is located in the first section 325. Since the outer tab 32 supports a smaller number of tabs 32, or even does not need to support its tab 32, the outer tab 32 does not need to be provided with a longer first insulating layer 321. In addition, the connection terminal 232 is usually electrically connected to the adapter 40 through the outer tab 32, and the area covered by the first insulating layer 321 on the outer tab 32 is small, which can ensure that the tab 32 has a sufficient area to be connected to the adapter 40. Increase the flow rate of the connection terminal 232 and the adapter 40.

[0124] According to some embodiments of the present application, the present application also provides a battery cell, which includes

[0125] According to some embodiments of the present application, the present application also provides a battery, comprising the battery cell described in any of the above schemes.

[0126] According to some embodiments of the present application, the present application further provides an electrical device, comprising the battery described in any of the above schemes, and the battery is used to provide electrical energy to the electrical device.

[0127] The power-consuming device may be any of the aforementioned devices or systems using batteries.

[0128] See also Figure 8 , Figure 8 Schematic diagram of a method for preparing a battery cell assembly 23 provided in an embodiment of the present application. The battery cell assembly 23 may be Figures 3 to 7 The battery cell assembly 23 of any embodiment.

[0129] According to some embodiments of the present application, Figure 8 As shown, the preparation method of the battery cell assembly 23 provided in the present application includes:

[0130] Step S01: providing a pole piece 30 , the pole piece 30 comprising a main body 31 extending along a first direction and pole ears 32 extending from the main body 31 along a second direction, wherein a plurality of pole ears 32 are spaced apart and distributed along the second direction on the same side of the main body 31 .

[0131] Step S02: Coating a first insulating layer 321 on the area of ​​the pole tab 32 adjacent to the main body 31, and in at least two pole tabs 32 adjacent to each other along the first direction, an extension height of the first insulating layer 321 on the preceding pole tab 32 in the second direction is less than an extension height of the first insulating layer 321 on the succeeding pole tab 32.

[0132] Step S03: Winding the pole piece 30 to form a battery cell assembly 23, the battery cell assembly 23 includes a main body 231 formed by winding a main body 31 and a connecting terminal 232 which is stacked by a plurality of pole ears 32 and extends along a preset bending path, the pole ears 32 are bent to form an angle area a, and in at least two adjacent layers of pole ears 32, the length of the first insulating layer 321 on the pole ear 32 away from the angle area a is less than the length of the first insulating layer 321 on the pole ear 32 close to the angle area a.

[0133] The cell assembly 23 prepared by the preparation method provided in the embodiment of the present application has a first insulating layer on the pole ear 32, and in at least two adjacent layers of pole ears 32, the length of the first insulating layer 321 on the inner pole ear 32 is longer, and the first insulating layer 321 can provide better protection to the inner pole ear 32, and improve the problem of easy damage caused by the small bending angle of the inner pole ear 32. And by providing a longer first insulating layer 321 on the inner pole ear 32, the structural strength of the inner pole ear 32 can be improved, and the supporting effect of the inner pole ear 32 on the outer pole ear 32 can be improved, and the problem of the outer pole ear 32 bending and deformation and easy insertion into the inner pole ear 32 causing a short circuit can be improved.

[0134] According to some embodiments of the present application, see Figures 3 to 7 The present application provides a pole piece 30, which includes: a main body 31 extending along a first direction; a pole ear 32 extending from the main body 31 along a second direction, and a plurality of pole ears 32 are spaced apart and distributed along the first direction on the same side of the main body 31. A first insulating layer 321 is coated in the region adjacent to the main body 31 on the pole ear 32, and the first insulating layer 321 has a height extending along the second direction. In any two adjacent pole ears 32, the height of the first insulating layer 321 on the front pole ear 32 is less than the height of the first insulating layer 321 on the rear pole ear 32. On the pole ear 32 near at least one end of the main body 31 in the first direction, the first insulating layer 321 extends to the bending region 322 of the pole ear 32. A second insulating layer 311 is coated in the region adjacent to the pole ear 32 on the main body 31, and the second insulating layer 311 is extended and formed along the first direction. The second insulating layer 311 and the first insulating layer 321 are in contact with each other, and the first insulating layer 321 and the second insulating layer 311 can be coated and formed in the same process step.

[0135] According to some embodiments of the present application, see Figures 3 to 7The present application provides a battery cell assembly 23, which is formed by winding the above-mentioned pole piece 30. The battery cell assembly 23 includes a main body 231 formed by winding a main body 31 and a connection terminal 232 formed by stacking a plurality of pole tabs 32 and extending along a preset bending path, wherein the first section 325 and the second section 326 of the pole tabs 32 intersectingly arranged and the angle region a between the first section 325 and the second section 326, in any two adjacent layers of pole tabs 32, the length of the first insulating layer 321 on the pole tab 32 away from the angle region a is less than the length of the first insulating layer 321 on the pole tab 32 close to the angle region a. The first insulating layer 321 on at least one layer of the pole tab 32 extends and covers the bending region 322 of the pole tab 32.

[0136] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A pole piece (30) for winding to form a battery cell assembly (23), characterized in that: The pole piece (30) comprises: A main body (31) extending along a first direction; A pole lug (32) extends from the main body (31) along the second direction, and a plurality of pole lugs (32) are spaced apart and distributed along the first direction on the same side of the main body (31). The pole lug (32) is coated with a first insulating layer (321), the first insulating layer (321) having a height extending along the second direction, and in at least two adjacent pole lugs (32), the height of the first insulating layer (321) on the first pole lug (32) is smaller than the height of the first insulating layer (321) on the second pole lug (32).

2. The pole piece (30) according to claim 1, characterized in that: The pole tab (32) has two surfaces arranged opposite to each other, and both surfaces are coated with the first insulating layer (321).

3. The pole piece (30) according to claim 1, characterized in that: The pole lug (32) has a bending area (322), and the pole lug (32) is used to bend in the bending area (322) to form a connection terminal (232) of the battery cell assembly (23); and in at least two adjacent pole lugs (32), the height of the first insulating layer (321) on the first pole lug (32) in the bending area (322) is smaller than the height of the first insulating layer (321) on the second pole lug (32) in the bending area (322).

4. The pole piece (30) according to claim 1, characterized in that: The electrode tab (32) further comprises a welding area (323) located on a side of the first insulating layer (321) away from the main body (31), and a distance between the first insulating layer (321) and the welding area (323) in the second direction is 2 mm to 6 mm.

5. The pole piece (30) according to claim 4, characterized in that: The pole lug (32) has a first edge (324) on a side away from the main body (31), and the distance between the welding area (323) and the first edge (324) is 1 mm to 3 mm.

6. The pole piece (30) according to claim 1, characterized in that: The first insulating layer (321) is coated on the electrode tab (32) in an area adjacent to the main body (31).

7. The pole piece (30) according to claim 6, characterized in that: The main body (31) is coated with a second insulating layer (311), the second insulating layer (311) is located on a side of the main body (31) facing the pole lug (32), and the second insulating layer (311) is connected to the first insulating layer (321).

8. The pole piece (30) according to claim 7, characterized in that: The height of the second insulating layer (311) in the second direction is 2 mm to 4 mm.

9. The pole piece (30) according to claim 1, characterized in that: The main body comprises a second edge (312) located between two adjacent pole tabs (32), and a maximum distance between the first insulating layer (321) and the second edge (312) in the second direction is greater than or equal to 1 mm.

10. The pole piece (30) according to claim 1, characterized in that: One or more of the pole lugs (32) form a plurality of pole lug (32) groups, and in two adjacent pole lug (32) groups along the first direction, the height of the first insulating layer (321) in the first pole lug (32) group is smaller than the height of the first insulating layer (321) in the second pole lug (32) group.

11. The pole piece (30) according to claim 9, characterized in that: The first insulating layer (321) on the pole tabs (32) in the same pole tab (32) group has the same height.

12. A battery cell assembly (23), characterized in that: The battery cell assembly (23) is formed by winding the pole piece (30) according to any one of claims 1 to 11, and the battery cell assembly (23) comprises a main body (231) formed by winding the main body (31) and a connecting terminal (232) formed by stacking a plurality of pole tabs (32) and extending along a preset bending path. Among them, the first section (325) and the second section (326) of the pole lug (32) are arranged to intersect, and the angle region (a) between the first section (325) and the second section (326), in at least two adjacent layers of the pole lug (32), the length of the first insulating layer (321) on the pole lug (32) away from the angle region (a) is shorter than the length of the first insulating layer (321) on the pole lug (32) close to the angle region (a).

13. The battery cell assembly (23) according to claim 12, characterized in that: The pole lug (32) has a bending area (322), and the pole lug (32) is used to bend in the bending area (322) to form a connection terminal (232) of the battery cell assembly (23); in at least two adjacent pole lugs (32), the length of the first insulating layer (321) on the first pole lug (32) in the bending area (322) is smaller than the length of the first insulating layer (321) on the second pole lug (32) in the bending area (322).

14. The battery cell assembly (23) according to any one of claims 12 to 13, characterized in that: The second section (326) is located on a side of the first section (325) away from the main body (231); The first insulating layer (321) on at least one of the pole tabs (32) close to the angle region (a) extends from the first section (325) to the second section (326); And / or, the first insulating layer (321) on at least one of the pole tabs (32) away from the angle region (a) is located in the first section (325).

15. A battery cell, characterized in that: Comprising the battery cell assembly (23) according to any one of claims 12 to 14.

16. A battery, characterized in that: It comprises the battery cell assembly (23) according to any one of claims 12 to 14, or the battery cell according to claim 15.

17. An electrical device, characterized in that: The electrical device comprises the battery as claimed in claim 16, and the battery is used to provide electrical energy.

18. A method for preparing a battery core assembly, characterized in that: include: Provided is a pole piece, the pole piece comprising a main body extending along a first direction and a pole ear extending from the main body along a second direction, wherein a plurality of pole ears are spaced and distributed along the second direction on the same side of the main body; A first insulating layer is coated on the area of ​​the tab adjacent to the main body, and of at least two tabs adjacent to each other along the first direction, an extension height of the first insulating layer on the first tab in the second direction is smaller than an extension height of the first insulating layer on the second tab in the second direction; The pole piece is wound to form a battery cell assembly, and the battery cell assembly includes a main body formed by winding the main body and a connecting terminal which is stacked by a plurality of the pole ears and extends along a preset bending path, and the pole ears are bent to form an angle area. In at least two adjacent layers of the pole ears, the length of the first insulating layer on the pole ears away from the angle area is less than the length of the first insulating layer on the pole ears close to the angle area.

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