Battery cells, related devices, systems, and charging networks

Abstract

This application relates to the field of power battery technology, and proposes a battery cell (100), related devices, systems and charging networks. The battery cell (100) includes an electrode (11), which includes: a current collector (111), the current collector (111) including two end faces (1111a) located at opposite ends along the width direction of the current collector (111), and the current collector (111) also including two side faces (1111b) located at opposite sides along the thickness direction of the current collector (111); an insulating layer (113) disposed on the current collector (111), the insulating layer (113) covering the end faces (1111a), and the insulating layer (113) The first cover (113a) and the second cover (113b) are formed respectively on the two sides (1111b). On the same projection plane perpendicular to the thickness direction of the current collector (111), the size of the orthographic projection of the first cover (113a) and the size of the orthographic projection of the second cover (113b) are different. In the battery cell (100) provided in this application embodiment, the burrs on the end face (1111a) are covered by the insulating layer (113), so that the width of the insulating layer (113) on both sides of the current collector (111) is different, so as to alleviate the stress concentration of the electrode (11) at the insulating layer (113).

Description

Battery cell, related device, system and charging network TECHNICAL FIELD

[0001] The present application belongs to the technical field of power batteries, and particularly relates to a battery cell, a related device, a system and a charging network. BACKGROUND

[0002] Energy saving and emission reduction is 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 energy saving and environmental protection advantages. For electric vehicles, battery technology is an important factor for their development.

[0003] During the manufacturing process of the battery, the burrs generated during the processing of the pole piece are usually covered by structural members such as adhesive tape to reduce the negative impact of the burrs on the battery. However, during the winding of the pole piece into an electrode assembly, stress concentration is prone to occur at the corners and large faces of the electrode assembly, resulting in damage to the pole piece.

[0004] SUMMARY

[0005] In view of the above problems, the present application provides a battery cell, a related device, a system and a charging network, which can alleviate the problem of stress concentration of the pole piece at the adhesive tape, which leads to damage to the pole piece.

[0006] In a first aspect, the embodiments of the present application provide a battery cell, comprising a pole piece, the pole piece comprising: a current collector, the current collector comprising two end faces located at opposite ends along the width direction of the current collector, and the current collector further comprising two side faces located at opposite sides along the thickness direction of the current collector; an insulating layer provided on the current collector, the insulating layer covering the end faces, and the insulating layer also covering part of the two side faces and forming a first covering face and a second covering face, respectively; on the same projection plane perpendicular to the thickness direction of the current collector, the size of the orthographic projection of the first covering face in the width direction of the current collector is different from the size of the orthographic projection of the second covering face in the width direction of the current collector.

[0007] In the technical solution of the present embodiment, the insulating layer is provided to cover the burrs on the end faces, thereby reducing the risk of the burrs piercing the separator and causing short circuit of adjacent pole pieces; the widths of the part of the insulating layer located at the two sides of the current collector are made different, so as to alleviate the stress concentration of the pole piece at the insulating layer, thereby reducing the risk of deformation and damage of the pole piece, and improving the safety performance and stability of the battery cell.

[0008] In some embodiments, on the same projection plane perpendicular to the thickness direction of the current collector, the difference between the size of the orthographic projection of the first covering face in the width direction of the current collector and the size of the orthographic projection of the second covering face in the width direction of the current collector is less than or equal to 1 mm.

[0009] The technical scheme of the embodiment provides a width difference of some portions of the insulating layer on the two side surfaces, so that the width of the insulating layer is not too large, thereby reducing the negative influence of the insulating layer on the energy density of the battery monomer, and the stress concentration of the pole piece at the insulating layer is also reduced.

[0010] In some embodiments, the current collector comprises a first body portion and a tab portion connected to the first body portion, the side surface and the end surface are formed on the first body portion, the tab portion extends from any one of the two end surfaces in a width direction of the current collector and away from the first body portion, the insulating layer covers at least part of the tab portion, and the insulating layer also covers the end surface connected to the tab portion.

[0011] In the technical scheme of the embodiment, the insulating layer can cover the end surface of the body portion to cover burrs on the end surface, thereby reducing the case that the burrs pierce the diaphragm and contact the adjacent other pole piece; the insulating layer can also cover at least part of the tab portion to strengthen the strength of the connection part between the tab portion and the body portion, thereby reducing the case that the tab portion is torn; and the arrangement of the insulating layer is also reduced in difficulty.

[0012] In some embodiments, the insulating layer comprises two sub-insulating layers corresponding to the two side surfaces, the sub-insulating layer comprises a first portion and a second portion connected to the first portion, the second portion is connected to the side surface, and the first covering surface and the second covering surface are respectively the surfaces of the two second portions connected to the corresponding side surfaces; at least part of the first portion is connected to the first portion of the adjacent other sub-insulating layer to cover the corresponding end surface, and at least part of the first portion covers at least part of the tab portion.

[0013] The technical scheme of the embodiment provides a specific structure of the insulating layer, so that the insulating layer is formed by the mutual connection of the two sub-insulating layers; the sub-insulating layer comprises the first portion and the second portion, and the first portion covers at least part of the tab portion to improve the connection strength between the tab portion and the body portion.

[0014] In some embodiments, in the width direction of the current collector, the ratio between the size of the first portion and the size of the tab portion is less than or equal to 1:3.

[0015] The technical scheme of the embodiment provides a width range of the first portion covering the tab portion, so that the first portion can not only strengthen the connection strength between the tab portion and the body portion, but also reduce the negative influence of the first portion on the conduction performance of the tab portion.

[0016] In some embodiments, the sizes of the two sub-insulating layers in the width direction of the current collector are the same; in the width direction of the current collector, the sizes of the first portions of the two sub-insulating layers are different, and the ratio between the size of each first portion and the size of the tab portion is less than or equal to 1:3.

[0017] The two sub-insulating layers of the insulating layer have the same width, and the two sub-insulating layers are partially staggered, so that the stress concentration of the pole piece at the insulating layer can be relieved, the manufacturing difficulty of the insulating layer can be reduced, and the difficulty of arranging the insulating layer on the current collector can be reduced. The two sub-insulating layers of the present embodiment also cover the width range of the tab part, so as to reduce the negative influence of the sub-insulating layer on the conduction performance of the tab part.

[0018] In some embodiments, the pole piece further comprises an active material layer arranged on the side surface, the active material layer covers part of the side surface, and a blank area is formed on the side surface close to one side of the tab part, and the second part covers at least part of the blank area.

[0019] In the technical solution of the present embodiment, the second part can cover at least part of the blank area of the first main part, so as to protect the first main part, and at the same time, the area of the first main part exposed to the outside can be reduced, so as to reduce the occurrence of short circuit and the like, and improve the safety performance of the battery monomer.

[0020] In some embodiments, the sub-insulating layer further comprises a third part connected to the second part on the side opposite to the first part, the second part covers the blank area, and the third part covers part of the active material layer.

[0021] In the technical solution of the present embodiment, the sub-insulating layer further comprises a third part, and the third part covers part of the active material layer, so that the second part can completely cover the blank area, thereby further improving the safety performance of the battery monomer.

[0022] In some embodiments, the active material layer comprises a second main part arranged on the side surface and a transition part connected to the second main part, the transition part is arranged on the side of the second main part facing the blank area, the thickness of the transition part gradually decreases along the direction from the second main part to the blank area, and the third part covers at least part of the transition part.

[0023] In the technical solution of the present embodiment, the active material layer comprises a transition part with gradually decreasing thickness, and the third part covers at least part of the transition part, so as to reduce the height of the third part protruding from the active material layer, thereby reducing the negative influence of the insulating layer on the energy density of the battery monomer, and further relieving the stress concentration of the pole piece at the insulating layer.

[0024] In some embodiments, in the width direction of the current collector, the size range of the transition part is 0.2mm-10mm.

[0025] The technical solution of the present embodiment provides a width range of some transition parts, so that the third part can be stably connected to the transition part, and at the same time, the negative influence of the third part on the charge and discharge capacity of the active material layer can be reduced.

[0026] In some embodiments, the size of the transition portion ranges from 0.55mm to 2.15mm in the width direction of the current collector.

[0027] The technical solution of the present embodiment further provides a width range of some transition portions, and in the case that the third portion can be stably connected to the transition portion, the setting can further reduce the negative influence of the third portion on the charge and discharge capacity of the active material layer.

[0028] In some embodiments, the maximum distance between the side of the third portion away from the corresponding side surface and the corresponding side surface is less than or equal to the thickness of the second main portion.

[0029] In the technical solution of the present embodiment, the distance between the side of the third portion away from the corresponding side surface and the side surface is less than the thickness of the second main portion, so that the third portion is difficult to protrude from the active material layer, thereby further reducing the negative influence of the insulating layer on the energy density of the battery monomer, and further relieving the stress concentration of the pole piece at the insulating layer.

[0030] In some embodiments, the sub-insulating layer comprises a substrate layer and an adhesive layer provided on the substrate layer, and the adhesive layer is provided on the side of the substrate layer facing the current collector.

[0031] The technical solution of the present embodiment provides the structure of some sub-insulating layers, so that the sub-insulating layer comprises an adhesive layer and a substrate layer, so that the substrate layer can be connected to the current collector through the adhesive layer, and can wrap the burrs on the end face through the adhesive layer, and the burrs are difficult to pierce the insulating layer through the substrate layer; at the same time, the substrate layer can also play a role in protecting the current collector.

[0032] In some embodiments, the substrate layer is an insulating structure layer.

[0033] In the technical solution of the present embodiment, the substrate layer is an insulating structure layer, so as to reduce the risk of short circuit of the current collector.

[0034] In some embodiments, the thickness of the substrate layer ranges from 6μm to 20μm.

[0035] The technical solution of the present embodiment provides a thickness range of some substrate layers, so that the burrs are difficult to pierce the substrate layer, and the substrate layer can provide protection for the current collector; this setting can also make the substrate layer not easy to be punctured by static electricity, so that the substrate layer can better protect the current collector.

[0036] In some embodiments, the adhesive layer is an adhesive structure layer.

[0037] In the technical solution of the present embodiment, the adhesive layer is an adhesive structure layer, so as to adhere the substrate layer to the current collector and / or the active material layer; at the same time, the adhesive layer can also coat the burrs on the end face, so as to reduce the risk of the burrs piercing the insulating layer.

[0038] In some embodiments, the thickness of the adhesive layer ranges from 3 μm to 10 μm.

[0039] The technical solution of the present embodiment provides a thickness range of the adhesive layer, so that the adhesive layer can stably bond the substrate layer to the current collector and / or the active material layer, and the adhesive layer can also hinder the burr from piercing the insulation layer.

[0040] In some embodiments, the peeling strength of the insulation layer ranges from 15 N / m to 20 N / m.

[0041] The technical solution of the present embodiment provides a peeling strength range of the insulation layer, so that the insulation layer is difficult to separate from the current collector and / or the active material layer, thereby enabling the insulation layer to still have strong connection stability in the environment of electrolyte infiltration.

[0042] In some embodiments, the needle penetration strength of the insulation layer is greater than or equal to 300 gf.

[0043] The technical solution of the present embodiment provides a needle penetration strength range of the insulation layer, so that the burr is difficult to pierce the insulation layer, thereby enabling the insulation layer to better reduce the risk of short circuiting of the burr and the adjacent pole piece.

[0044] In some embodiments, the battery monomer further comprises an electrode assembly, the electrode assembly comprising a positive pole piece, a diaphragm and a negative pole piece arranged in sequence; the pole piece is a positive pole piece.

[0045] In the technical solution of the present embodiment, the burr generated by the processing of the positive pole piece is more harmful to the short circuiting of the active material layer of the negative pole piece, so the present embodiment makes the pole piece a positive pole piece to reduce the safety risk caused by the short circuiting of the burr.

[0046] In a second aspect, some embodiments of the present application further provide a battery device comprising the battery monomer provided by some embodiments of the first aspect.

[0047] In a third aspect, some embodiments of the present application further provide an energy storage device comprising a plurality of battery monomers provided by some embodiments of the first aspect, or a plurality of battery devices provided by some embodiments of the second aspect.

[0048] The battery monomer or the battery device is used for storing or providing electric energy.

[0049] In a fourth aspect, some embodiments of the present application further provide an energy storage system comprising a power conversion device and an energy storage device provided by some embodiments of the third aspect, the power conversion device being used for electrically connecting a power generation device and the energy storage device.

[0050] In a fifth aspect, some embodiments of the present application further provide a power consuming device, characterized in that it comprises the battery cell provided by some embodiments of the first aspect, the battery device provided by some embodiments of the second aspect, the energy storage device provided by some embodiments of the third aspect, or the energy storage system provided by some embodiments of the fourth aspect, the battery cell or the battery device being used for storing or providing electric energy.

[0051] In a sixth aspect, some embodiments of the present application further provide a charging network, comprising a charging pile and the energy storage device provided by some embodiments of the third aspect, or the energy storage system provided by some embodiments of the fourth aspect;

[0052] The energy storage device or the energy storage system is used for providing electric energy for the charging pile.

[0053] The above description is only a summary of the technical solutions of the present application. In order to enable one of ordinary skill in the art to better understand the technical means of the present application and to carry it out according to the content of the description, and in order to enable the above and other purposes, characteristics and advantages of the present application to be more apparent and easy to understand, the following specific embodiments of the present application are described in detail. BRIEF DESCRIPTION OF DRAWINGS

[0054] Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The accompanying drawings are included to provide a description of the preferred embodiments and are not meant to limit the present application. Moreover, the same reference numerals in the attached drawings indicate the same or similar components. In the drawings:

[0055] FIG. 1 is a structural schematic diagram of a vehicle provided by some embodiments of the present application;

[0056] FIG. 2 is an exploded structural schematic diagram of a battery device according to some embodiments of the present application;

[0057] FIG. 3 is an exploded structural schematic diagram of a battery cell according to some embodiments of the present application;

[0058] FIG. 4 is a structural schematic diagram of an electrode assembly according to some embodiments of the present application;

[0059] FIG. 5 is a cross-sectional structural schematic diagram of an electrode assembly according to some embodiments of the present application;

[0060] FIG. 6 is a structural schematic diagram of a pole piece according to some embodiments of the present application;

[0061] FIG. 7 is a cross-sectional schematic diagram I of A-A in FIG. 6;

[0062] FIG. 8 is a cross-sectional schematic diagram II of A-A in FIG. 6;

[0063] FIG. 9 is a cross-sectional schematic diagram I of B-B in FIG. 6;

[0064] Fig. 10 is a schematic view of a section at B-B in Fig. 6;

[0065] Fig. 11 is a schematic view of a section at C in Fig. 7;

[0066] Fig. 12 is a schematic view of a section at D in Fig. 7;

[0067] Fig. 13 is a schematic view of a structure of an energy storage system according to some embodiments of the present application;

[0068] Fig. 14 is a schematic view of a structure of a charging network according to some embodiments of the present application.

[0069] The meanings of the reference signs in the figures are as follows:

[0070] 1, energy storage device; 2, power conversion device; 3, power generation device; 4, charging post; 5, connector;

[0071] 1000, battery device;

[0072] 100, battery cell;

[0073] 10, electrode assembly; 11, electrode sheet; 111, current collector; 1111, first main portion; 1111a, end surface; 1111b, side surface; 1111c, blank area; 1112, tab portion; 112, active material layer; 1121, second main portion; 1122, transition portion; 113, insulating layer; 113a, first covering surface; 113b, second covering surface; 1131, sub-insulating layer; 1131a, first portion; 1131b, second portion; 1131c, third portion; 1131d, base material layer; 1131e, adhesive layer; 114, positive electrode sheet; 115, negative electrode sheet; 12, separator;

[0074] 20, housing;

[0075] 30, end cap;

[0076] 40, electrode terminal;

[0077] 200, box; 201, upper box; 202, lower box;

[0078] 2000, motor;

[0079] 3000, controller. Embodiments of the present application

[0080] 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 more clearly illustrate the technical solutions of the present application, and therefore only serve as examples, and cannot limit the protection scope of the present application.

[0081] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of this application; the use of the terms "including," "comprising," or "having" and variations thereof herein is intended to be broad and encompass the terms "consisting of" and "consisting essentially of" and variations thereof. Unless otherwise noted, the terms "including" and "comprising" are open-ended and do not exclude the presence of unrecited elements or limitations.

[0082] 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 "a plurality of" is two or more, unless otherwise explicitly and specifically limited.

[0083] Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearance of the phrase in various places in the specification does not necessarily all refer to the same embodiment, nor is it necessarily independent or alternative embodiments to each other. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0084] 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, which means that there can be three relationships, for example, A and / or B, which means that there are three cases of A alone, A and B together, and B alone. In addition, the character " / " herein generally represents an "or" relationship between the front and rear associated objects.

[0085] In the description of the embodiments of the present application, the term "a plurality of" refers to two or more (including two), and similarly, "a plurality of groups" refers to two or more groups (including two groups), and "a plurality of pieces" refers to two or more pieces (including two pieces).

[0086] 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", and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the embodiments of the present application and simplifying the description, and therefore cannot be understood as limiting the embodiments of the present application, which do not indicate or imply that the indicated devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the embodiments of the present application.

[0087] In the description of the embodiments of the present application, unless otherwise explicitly specified and limited, the technical terms "mount", "connect", "connect", "fix" and other terms should be understood in a broad sense, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0088] At present, from the development of market situation, the application of power battery is more and more widely. Power battery is not only applied to energy storage power supply system of water power, thermal power, wind power and solar power station, but also widely applied to electric bicycles, electric motorcycles, electric vehicles and other electric vehicles, military equipment, aerospace and other fields. With the continuous expansion of the application field of power battery, the demand of its market is also increasing.

[0089] During the manufacturing process of the battery, the composite electrode sheet and the separator need to be cut. However, after cutting, burrs are easily generated on the cut section of the electrode sheet. The burrs are easy to pierce the adjacent separator and contact the adjacent electrode sheet, thereby easily causing short circuit of the adjacent electrode sheet and leading to short circuit, which further easily causes negative impact on the performance of the battery, and also easily leads to the risk of thermal runaway of the battery.

[0090] In order to alleviate the problem of short circuit of adjacent electrode sheets caused by burrs piercing the separator, the number of burrs generated during the cutting of the electrode sheet can be reduced. However, this requires improvement of the winding and die cutting equipment, which is too high in cost and difficult to eliminate burrs. A small amount of burrs on the section of the electrode sheet still exist the risk of piercing the separator and causing short circuit of the adjacent electrode sheet.

[0091] At present, there is also a way to reduce the negative impact of burrs by covering the burrs with adhesive tape on the electrode sheet. The adhesive tape covers the end face of the electrode sheet and part of the side face connected to the end face, so as to cover the burrs with the adhesive tape and reduce the risk of burrs piercing the separator. However, after the electrode sheet is wound and hot pressed to form an electrode assembly, stress concentration is easily generated at the position adjacent to the adhesive tape on the corner and large face of the electrode assembly, thereby easily causing deformation and damage of the electrode sheet.

[0092] Based on the above considerations, in order to alleviate the problem of short circuit of adjacent electrode sheets caused by burrs piercing the separator, the embodiments of the present application provide a battery monomer. An insulating layer is arranged on the electrode sheet of the battery monomer to cover the end face and part of the side face of the current collector. At the same time, the width of the insulating layer on the two side faces is different.

[0093] In the battery cell, the insulation layer can cover the burrs on the end face to reduce the risk of the burrs piercing the diaphragm to cause short circuit of adjacent pole pieces; the width of the part of the insulation layer located on both sides of the current collector is different to alleviate the stress concentration, thereby reducing the risk of deformation and damage of the pole piece, and improving the safety performance and stability of the battery cell.

[0094] The battery cell disclosed in the embodiments of the present application can be used in a power consumption device using the battery device as a power source or a variety of energy storage systems using the battery device as an energy storage element. The power consumption device can be, but is not limited to, a mobile phone, a tablet, a notebook computer, an electric toy, an electric tool, an electric vehicle, an electric automobile, a ship, a spacecraft, etc. Among them, the electric toy can include a fixed or mobile electric toy, such as a game console, an electric automobile toy, an electric ship toy, and an electric aircraft toy, etc., and the spacecraft can include an airplane, a rocket, a space shuttle, a spacecraft, etc.

[0095] The following embodiments are described by taking a vehicle as an example for convenience of description.

[0096] Referring to FIG. 1, FIG. 1 is a structural schematic diagram of a vehicle as a power consumption device according to some embodiments of the present application. The vehicle can be a fuel automobile, a gas automobile, or a new energy automobile, and the new energy automobile can be a pure electric automobile, a hybrid electric automobile, or a range extended automobile, etc. The vehicle is internally provided with a battery device 1000, which can be arranged at the bottom, the head, or the tail of the vehicle. The battery device 1000 can be used for power supply of the vehicle, for example, the battery device 1000 can be used as an operating power source of the vehicle. The vehicle can further include a controller 3000 and a motor 2000, and the controller 3000 is used to control the battery device 1000 to supply power to the motor 2000, for example, to meet the working power demand of the vehicle during starting, navigation, and driving.

[0097] In some embodiments of the present application, the battery device 1000 can not only be used as an operating power source of the vehicle, but also be used as a driving power source of the vehicle, to replace or partially replace fuel or natural gas to provide driving power for the vehicle.

[0098] Referring to FIG. 2, FIG. 2 is an exploded structural schematic diagram of a battery device 1000 according to some embodiments of the present application. The battery device 1000 includes a case 20 and a battery cell 100, and the battery cell 100 is accommodated in the case 20. The case 20 is used to provide an accommodation space for the battery cell 100, and the case 20 can adopt various structures. In some embodiments, the case 20 can include an upper case 201 and a lower case 202, and the upper case 201 and the lower case 202 are mutually covered to jointly define an accommodation space for accommodating the battery cell 100. The lower case 202 can be a hollow structure with one end open, and the upper case 201 can be a plate structure, which is covered on the open side of the lower case 202 to jointly define the accommodation space with the lower case 202. Alternatively, the upper case 201 and the lower case 202 can both be hollow structures with one side open, and the open side of the upper case 201 is covered on the open side of the lower case 202. Of course, the case 20 formed by the upper case 201 and the lower case 202 can have various shapes, such as a cylinder, a cuboid, etc.

[0099] In the battery device 1000, the battery cell 100 can be multiple, and the multiple battery cells 100 can be connected in series, in parallel, or in a mixed connection. The mixed connection means that the multiple battery cells 100 are connected in series and in parallel. The multiple battery cells 100 can be directly connected in series, in parallel, or in a mixed connection, and then the whole of the multiple battery cells 100 is accommodated in the case 20. Of course, the battery device 1000 can also be that the multiple battery cells 100 are first connected in series, in parallel, or in a mixed connection to form a battery module, and then the multiple battery modules are connected in series, in parallel, or in a mixed connection to form a whole, which is accommodated in the case 20. The battery device 1000 can further include other structures, for example, the battery device 1000 can further include a current collecting component for realizing the electrical connection between the multiple battery cells 100.

[0100] Each battery cell 100 can be a secondary battery or a primary battery, and can also be a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery, but is not limited thereto. The battery cell 100 can have a cylindrical shape, a flat shape, a cuboid shape, or other shapes, etc.

[0101] Referring to FIG. 2 and FIG. 3, the battery cell 100 refers to the smallest unit that constitutes the battery device 1000. As shown in FIG. 3, the battery cell 100 includes an end cover 30, a case 20, an electrode assembly 10, and other functional components.

[0102] The end cover 30 refers to a component that covers the opening of the shell 20 to isolate the internal environment of the battery cell 100 from the external environment. Without limitation, the shape of the end cover 30 can be adapted to the shape of the shell 20 to fit the shell 20. Optionally, the end cover 30 can be made of a material with certain hardness and strength, such as aluminum alloy, so that the end cover 30 is not easily deformed when subjected to extrusion collision, so that the battery cell 100 can have higher structural strength, and the safety performance can also be improved. The end cover 30 can be provided with functional components such as electrode terminals 40. The electrode terminals 40 can be used to electrically connect with the electrode assembly 10 for outputting or inputting the electrical energy of the battery cell 100. In some embodiments, the end cover 30 can also be provided with a pressure relief mechanism for relieving the internal pressure of the battery cell 100 when the internal pressure or temperature of the battery cell 100 reaches a threshold value. The material of the end cover 30 can also be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and the embodiments of the present application do not make special limitations. In some embodiments, an insulating member can also be provided on the inner side of the end cover 30, which can be used to isolate the electrical connection components in the shell 20 from the end cover 30 to reduce the risk of short circuit. For example, the insulating member can be plastic, rubber, etc.

[0103] The shell 20 is a component for fitting the end cover 30 to form the internal environment of the battery cell 100, wherein the formed internal environment can be used to accommodate the electrode assembly 10, the electrolyte and other components. The shell 20 and the end cover 30 can be independent components, and an opening can be provided on the shell 20, and the end cover 30 is covered on the opening to form the internal environment of the battery cell 100. Without limitation, the end cover 30 and the shell 20 can also be integrated, specifically, the end cover 30 and the shell 20 can form a common connecting surface before other components enter the shell, and when it is necessary to encapsulate the internal environment of the shell 20, the end cover 30 is covered on the shell 20. The shell 20 can be various shapes and various sizes, such as rectangular parallelepiped, cylindrical, hexagonal prism, etc. Specifically, the shape of the shell 20 can be determined according to the specific shape and size of the electrode assembly 10. The material of the shell 20 can be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and the embodiments of the present application do not make special limitations.

[0104] The electrode assembly 10 is a component in which electrochemical reactions occur in the battery cell 100. One or more electrode assemblies 10 can be contained within the case 20. The electrode assembly 10 is mainly formed by winding or layering a positive electrode sheet 114 and a negative electrode sheet 115, and a separator 12 is generally provided between the positive electrode sheet 114 and the negative electrode sheet 115. The positive electrode sheet 114 and the negative electrode sheet 115 have portions with active materials that constitute the main body of the electrode assembly 10, and portions without active materials that each constitute a tab. The positive and negative tabs can be located together at one end of the main body or at separate ends of the main body. During charging and discharging of the battery device 1000, the positive and negative active materials react with the electrolyte, and the tabs connect the electrode terminals 40 to form a current loop.

[0105] In a first aspect, with reference to FIGS. 4-10, some embodiments of the present application provide a battery cell 100, comprising an electrode sheet 11, the electrode sheet 11 comprising a current collector 111 and an insulating layer 113. The current collector 111 comprises two end faces 1111a located at opposite ends along a width direction of the current collector 111, and the current collector 111 further comprises two side faces 1111b located at opposite sides along a thickness direction of the current collector 111; the insulating layer 113 is provided on the current collector 111, the insulating layer 113 covers the end faces 1111a, and the insulating layer 113 also covers portions of the two side faces 1111b and forms a first covering face 113a and a second covering face 113b, respectively; in the same projection plane perpendicular to the thickness direction of the current collector 111, the size of the orthographic projection of the first covering face 113a in the width direction of the current collector 111 is different from the size of the orthographic projection of the second covering face 113b in the width direction of the current collector 111.

[0106] In the drawings, the direction in which the X-axis lies is the length direction of the electrode sheet 11 and also the length direction of the current collector 111; the direction in which the Y-axis lies is the width direction of the electrode sheet 11 and also the width direction of the current collector 111; the direction in which the Z-axis lies is the thickness direction of the electrode sheet 11 and also the thickness direction of the current collector 111.

[0107] The current collector 111 refers to a structure in the electrode sheet 11 that is mainly used to support current flow. The main function of the current collector 111 is to provide an ion conductor in electrochemical reactions to support the flow of current and separate the chemical reactions between the positive and negative electrodes, so that electrons flow in the external circuit to generate electrical energy. In an example, in a lithium ion battery device 1000, the current collector 111 can be a copper foil, an aluminum foil, or a structural member of other materials.

[0108] The current collector 111 includes an end surface 1111a and a side surface 1111b. The end surface 1111a refers to two surfaces of the current collector 111 located at opposite ends in the width direction Y of the current collector 111, and is also the surface of the pole piece 11 after slitting. The burr is usually formed on the end surface 1111a. The side surface 1111b refers to two surfaces of the current collector 111 located at opposite sides in the thickness direction Z of the current collector 111, and the active material is usually formed on the side surface 1111b.

[0109] The insulating layer 113 refers to a layered structure of the pole piece 11 mainly used for protecting the end surface 1111a of the pole piece 11. The insulating layer 113 covers the end surface 1111a of the current collector 111 and covers part of the side surface 1111b of the current collector 111, that is, the insulating layer 113 covers the corresponding end surface 1111a and also covers part of the adjacent side surface 1111b. The insulating layer 113 can cover only one end surface 1111a, or can be divided into two or more parts and cover two end surfaces 1111a respectively. According to the coverage area of the insulating layer 113, the insulating layer 113 can be a square, circular or other shaped layered structure, and the insulating layer 113 can also be a U-shaped, L-shaped or other shaped structure.

[0110] The insulating layer 113 covers the corresponding end surface 1111a and can also wrap the burr on the corresponding end surface 1111a inside the insulating layer 113, thereby reducing the direct contact between the burr and the diaphragm 12 and reducing the risk of the burr piercing the diaphragm 12.

[0111] The insulating layer 113 is arranged on the current collector 111. According to the structure of the insulating layer 113, the insulating layer 113 can be connected to the current collector 111 by adhesion, or can be connected to the current collector 111 by solidification or other means. For example, the insulating layer 113 can include insulating adhesive paper and be connected to the current collector 111 by adhesion. For example, the insulating layer 113 can also include a coating and be connected to the current collector 111 by spraying and solidification. It can be understood that the insulating layer 113 can also include other structures, not limited to the above two.

[0112] The insulating layer 113 also covers part of the two side surfaces 1111b adjacent to the corresponding end surface 1111a. The first coverage surface 113a is the surface of the insulating layer 113 opposite to one side surface 1111b, and the area of the first coverage surface 113a is the area of the insulating layer 113 covering the corresponding side surface 1111b. The second coverage surface 113b is the surface of the insulating layer 113 opposite to the other side surface 1111b, and the area of the second coverage surface 113b is the area of the insulating layer 113 covering the corresponding side surface 1111b.

[0113] The insulating layer 113 can be connected to the corresponding side surface 1111b or end surface 1111a, or both the corresponding side surface 1111b and end surface 1111a, due to the insulating layer 113 covering the end surface 1111a and part of the side surface 1111b adjacent to the end surface 1111a.

[0114] The number of the insulating layer 113 can be one or two due to the current collector 111 having two end surfaces 1111a along the width direction Y thereof; in the case of one insulating layer 113, the insulating layer 113 can cover either of the two end surfaces 1111a, and in the case of two insulating layers 113, the two insulating layers 113 can cover the two end surfaces 1111a respectively.

[0115] The insulating layer 113 has insulating properties, so that the insulating layer 113 has a large resistance, thereby improving the safety performance of the battery monomer 100; for example, in the case of short circuit caused by the short circuit of the pole piece 11 at the end surface 1111a to the adjacent other pole piece 11, the large resistance of the insulating layer 113 can reduce the short circuit current and reduce the heat generated by the short circuit, thereby achieving the effect of improving the safety performance of the battery monomer 100.

[0116] The projection plane perpendicular to the thickness direction of the current collector 111 refers to a virtual plane perpendicular to the thickness direction of the current collector 111, which is also parallel to the current collector 111.

[0117] The orthographic projection of the first covering surface 113a on the projection plane refers to the projection of the first covering surface 113a on the projection plane along the direction perpendicular to the projection plane, which is also the projection of the first covering surface 113a on the projection plane along the thickness direction Z of the current collector 111; the orthographic projection of the second covering surface 113b on the projection plane refers to the projection of the second covering surface 113b on the projection plane along the direction perpendicular to the projection plane, which is also the projection of the second covering surface 113b on the projection plane along the thickness direction Z of the current collector 111.

[0118] In the width direction Y of the current collector 111, the size of the orthographic projection of the first covering surface 113a is different from the size of the orthographic projection of the second covering surface 113b, that is, the width of the insulating layer 113 covering the two side surfaces 1111b is different; referring to FIG. 7 and FIG. 9, the sum of L2 and L3 can be the size of the orthographic projection of the first covering surface 113a in the width direction Y of the current collector 111, or the size of the orthographic projection of the second covering surface 113b in the width direction Y of the current collector 111, that is, the width of the corresponding side surface 1111b covered by the insulating layer 113.

[0119] In the process of processing the pole piece 11, the pole piece 11 needs to pass through the processes of winding and shaping, and the pole piece 11 needs to be pressed in the winding and shaping processes. In the case that the widths of the insulating layer 113 on the two side surfaces 1111b are the same, the pole piece 11 is prone to stress concentration at the insulating layer 113, thereby easily causing deformation damage of the pole piece 11. Accordingly, the widths of the insulating layer 113 on the two side surfaces 1111b are made different, so that the parts of the insulating layer 113 on the two side surfaces 1111b are partially staggered in the thickness direction Z of the pole piece 11, thereby being able to alleviate the stress concentration problem of the pole piece 11 in the winding, shaping or other pressing conditions.

[0120] In the embodiment, the insulating layer 113 is arranged to cover the burrs on the end surface 1111a through the insulating layer 113, so as to reduce the risk that the burrs pierce the diaphragm 12 to cause short circuit of the adjacent pole piece 11. The widths of the parts of the insulating layer 113 located on both sides of the current collector 111 are made different, so as to alleviate the stress concentration of the pole piece 11 at the insulating layer 113, thereby reducing the risk of deformation and damage of the pole piece 11 and improving the safety performance and stability of the battery monomer 100.

[0121] Referring to FIGS. 5 to 10, in some embodiments, the difference between the size of the orthographic projection of the first covering surface 113a in the width direction of the current collector 111 and the size of the orthographic projection of the second covering surface 113b in the width direction of the current collector 111 is less than or equal to 1 mm (millimeter) on the same projection plane perpendicular to the thickness direction of the current collector 111.

[0122] Referring to FIGS. 8 and 10, the difference between the widths of the orthographic projection of the first covering surface 113a and the orthographic projection of the second covering surface 111b is the size denoted by W in the figure, which is less than or equal to 1 mm. For example, the size can be 1 mm, 0.8 mm, 0.6 mm, 0.4 mm, 0.2 mm, 0.1 mm or other values.

[0123] It can be understood that, due to the different widths of the insulating layer 113 on the two side surfaces 1111b, the widths of the orthographic projection of the first covering surface 113a and the orthographic projection of the second covering surface 111b are different, so the difference between the widths of the orthographic projection of the insulating layer 113 on the two side surfaces 1111b should not be 0, that is, the areas of the two side surfaces 1111b covered by the insulating layer 113 are different.

[0124] For example, the difference between the widths of the orthographic projection of the first covering surface 113a and the orthographic projection of the second covering surface 111b can be 1 mm, in which case the difference between the widths of the insulating layer 113 on the two side surfaces 1111b is larger, so as to better alleviate the stress concentration of the pole piece 11 at the insulating layer 113.

[0125] For example, the difference between the width of the orthographic projection of the first covering surface 113a and the orthographic projection of the second covering surface 111b can be 0.5 mm, in which case the setting can both relieve the stress concentration of the pole piece 11 at the insulating layer 113 and relieve the excessive width of the insulating layer 113 on a certain side surface 1111b, thereby reducing the negative impact of the insulating layer 113 on the charge and discharge capability of the pole piece 11.

[0126] For example, the difference between the width of the orthographic projection of the first covering surface 113a and the orthographic projection of the second covering surface 111b can be 0.1 mm, in which case the width difference of the insulating layer 113 on the two side surfaces 1111b is small, so as to better reduce the negative impact of the insulating layer 113 on the charge and discharge capability of the pole piece 11.

[0127] The embodiment provides the width difference of some portions of the insulating layer 113 on the two side surfaces 1111b, which can make the width of the insulating layer 113 not too large, so as to reduce the negative impact of the insulating layer 113 on the energy density of the battery monomer 100, and the setting can also reduce the stress concentration of the pole piece 11 at the insulating layer 113.

[0128] Referring to FIGS. 6-10, in some embodiments, the current collector 111 includes a first body portion 1111 and a tab portion 1112 connected to the first body portion 1111, the side surface 1111b and the end surface 1111a are formed on the first body portion 1111, and the tab portion 1112 extends from any one of the two end surfaces 1111a in a direction away from the first body portion 1111 along the width direction of the current collector 111; the insulating layer 113 covers at least part of the tab portion 1112, and the insulating layer 113 also covers the end surface 1111a connected to the tab portion 1112.

[0129] The first body portion 1111 refers to a part of the current collector 111 for carrying active material, and the active material can be formed on the first body portion 1111; the end surface 1111a and the side surface 1111b both refer to the surface of the first body portion 1111, that is, the end surface 1111a refers to the two surfaces located at the opposite ends of the first body portion 1111 along the width direction Y of the current collector 111, and the side surface 1111b refers to the two surfaces located at the opposite sides of the first body portion 1111 along the thickness direction Z of the current collector 111.

[0130] The tab portion 1112 refers to a part of the current collector 111 extending outward from the first body portion 1111, and the tab portion 1112 is used to make the pole piece 11 conductive with the circuit outside the electrode assembly 10; the tab portion 1112 can be integrally formed with the first body portion 1111, or can be connected to the first body portion 1111 by means of gluing, welding or the like; the tab portion 1112 can be one, or two or more.

[0131] The tab portion 1112 extends from either of the two end faces 1111a to outside the first body portion 1111, and extends along the width direction Y of the current collector 111; the insulating layer 113 can cover the tab portion 1112 and the end face 1111a adjacent to the tab portion 1112, i.e., the insulating layer 113 is arranged on the end face 1111a adjacent to the tab portion 1112, and the insulating layer 113 can cover at least part of the tab portion 1112 in addition to covering the corresponding end face 1111a, at the position of the tab portion 1112 on the corresponding end face 1111a; at this time, the part of the insulating layer 113 covering the end face 1111a is connected to the corresponding end face 1111a, and the part of the insulating layer 113 covering the tab portion 1112 is connected to the corresponding tab portion 1112; for example, the insulating layer 113 covers at least the part of the tab portion 1112 close to the end face 1111a.

[0132] It can be understood that, when the number of the insulating layer 113 is one, the insulating layer 113 is arranged on the side of the current collector 111 having the tab portion 1112; when the number of the insulating layer 113 is two, one of the two insulating layers 113 is arranged on the side of the current collector 111 close to the tab portion 1112.

[0133] In the embodiment, the insulating layer 113 can cover the end face 1111a of the first body portion 1111 to cover the burr on the end face 1111a, thereby reducing the case that the burr pierces the diaphragm 12 and contacts the adjacent other tab 11; the insulating layer 113 can also cover at least part of the tab portion 1112 to strengthen the strength of the connection part of the tab portion 1112 and the first body portion 1111, thereby reducing the case that the tab portion 1112 is torn.

[0134] Referring to FIG. 10 in FIG. 6, in some embodiments, the insulating layer 113 includes two sub-insulating layers 1131 corresponding to the two side faces 1111b, the sub-insulating layer 1131 includes a first portion 1131a and a second portion 1131b connected to the first portion 1131a, the second portion 1131b is connected to the side face 1111b, and the first covering surface 113a and the second covering surface 113b are respectively the surfaces where the two second portions 1131b are connected to the corresponding side faces 1111b; at least part of the first portion 1131a is connected to the first portion 1131a of the adjacent other sub-insulating layer 1131 to cover the corresponding end face 1111a, and at least part of the first portion 1131a covers at least part of the tab portion 1112.

[0135] The sub-insulating layer 1131 refers to a part of the insulating layer 113, and there are two sub-insulating layers 1131, which can be combined to form the insulating layer 113; the two sub-insulating layers 1131 can be arranged on opposite sides of the current collector 111 and meet at the end surface 1111a of the current collector 111 to be connected, so that the insulating layer 113 can cover the end surface 1111a and part of the side surface 1111b.

[0136] The sub-insulating layer 1131 includes a first part 1131a and a second part 1131b. The second part 1131b is a part of the sub-insulating layer 1131 and is connected to the side surface 1111b to fix the sub-insulating layer 1131, and according to the material of the sub-insulating layer 1131, the second part 1131b can be bonded to the side surface 1111b or connected to the side surface 1111b by curing; the first part 1131a is also a part of the sub-insulating layer 1131 and is connected to the second part 1131b, and the first part 1131a can be integrally formed with the second part 1131b, or the first part 1131a can be connected to the second part 1131b by bonding, curing or the like.

[0137] The second part 1131b is connected to the side surface 1111b, the first covering surface 113a is the surface of one of the two second parts 1131b connected to the corresponding side surface 1111b, and the second covering surface 113b is the surface of the other of the two second parts 1131b connected to the corresponding side surface 1111b.

[0138] Since the second part 1131b is connected to the side surface 1111b, the first part 1131a can extend beyond the first main body part 1111, and since the insulating layer 113 is arranged on the side of the current collector 111 having the tab part 1112, at least part of the first part 1131a can be connected to the first part 1131a of the other sub-insulating layer 1131 adjacent to it, and at this time, the part of the first part 1131a can cover the corresponding end surface 1111a together with the other first part 1131a connected thereto; at least part of the first part 1131a covers at least part of the tab part 1112, and according to the length of the first part 1131a extending beyond the first main body part 1111, i.e. according to the size of the first part 1131a in the width direction Y of the current collector 111, the first part 1131a can completely cover the tab part 1112 or only cover part of the tab part 1112.

[0139] The first part 1131a can extend out of the first main body part 1111, and at least part of the two first parts 1131a can be connected to each other and cover the corresponding end face 1111a, at this time the two first parts 1131a can also play a role in correcting the direction of the burr, that is, under the action of the two first parts 1131a, the burr on the end face 1111a can extend in a direction parallel or approximately parallel to the width direction Y of the current collector 111, so that the burr is less likely to pierce the insulating layer 113, and also makes it more difficult for the burr to pierce the diaphragm 12 adjacent to the pole piece 11, thereby better reducing the risk of the burr piercing the diaphragm 12 and shorting with another pole piece 11.

[0140] It can be understood that because the first part 1131a is connected to the second part 1131b, and the second part 1131b is connected to the side face 1111b, in the case that the first part 1131a only covers part of the tab part 1112, the first part 1131a can at least cover the part of the tab part 1112 connected to the first main body part 1111.

[0141] Because the width of the insulating layer 113 covering the two side faces 1111b is different, the size of the two second parts 1131b in the width direction Y of the current collector 111 is different; the size of the two first parts 1131a in the width direction Y of the current collector 111 can be the same, at this time the size of the two sub-insulating layers 1131 in the width direction Y of the current collector 111 is different; the size of the two first parts 1131a in the width direction Y of the current collector 111 can also be different, at this time the size of the two sub-insulating layers 1131 in the width direction Y of the current collector 111 can be the same.

[0142] The embodiment provides a specific structure of some insulating layers 113, so that the insulating layer 113 is formed by two sub-insulating layers 1131 connected to each other; the sub-insulating layer 1131 includes a first part 1131a and a second part 1131b, and the first part 1131a covers at least part of the tab part 1112 to improve the connection strength of the tab part 1112 and the first main body part 1111.

[0143] Referring to FIGS. 6-10, in some embodiments, the ratio between the size of the first part 1131a and the size of the tab part 1112 in the width direction of the current collector 111 is less than or equal to 1:3.

[0144] The size of the first part 1131a in the width direction Y of the current collector 111 is the width size of the first part 1131a, because part of the first part 1131a covers the tab part 1112, that is, the size of the first part 1131a in the width direction Y of the current collector 111 is the size L1 shown in FIG. 7; because part of the first part 1131a is also connected to another first part 1131a, that is, the size of the first part 1131a in the width direction Y of the current collector 111 is also the size L1 shown in FIG. 9.

[0145] In the width direction of the current collector 111, the ratio between the size of the first part 1131a and the size of the tab part 1112 is less than or equal to 1:3, that is, the width of the first part 1131a is less than or equal to 1 / 3 of the width of the tab part 1112. The ratio can be 1:3, 1:4, 1:5, 1:6 or other ratios.

[0146] The sizes of the two first parts 1131a in the width direction of the current collector 111 can be the same or different. When the sizes of the two first parts 1131a are the same, the ratio between the size of each first part 1131a and the size of the tab part 1112 is less than 1:3 in the width direction of the current collector 111. When the sizes of the two first parts 1131a are different, the ratio between the size of each first part 1131a and the size of the tab part 1112 should also be less than 1:3 in the width direction of the current collector 111.

[0147] Referring to FIGS. 8 and 10, L11 and L12 are the sizes of the two first parts 1131a in the width direction Y of the current collector 111, and the ratio between the width of each first part 1131a and the width of the tab part 1112 is less than 1:3.

[0148] Making the width of the first part 1131a less than or equal to 1 / 3 of the width of the tab part 1112 enables the first part 1131a to be stably connected to another adjacent first part 1131a, so that the insulating layer 113 can cover the corresponding end face 1111a, thereby reducing the risk of burrs piercing the adjacent diaphragm 12. At the same time, this arrangement also enables the width of the connection site of the first part 1131a and another adjacent first part 1131a to be not too large, thereby reducing the interference of the first part 1131a with the arrangement of the diaphragm 12.

[0149] Making the width of the first part 1131a less than or equal to 1 / 3 of the width of the tab part 1112 also enables the first part 1131a to cover part of the tab part 1112, thereby enhancing the connection strength of the tab part 1112 and the first main body part 1111 and reducing the occurrence of tearing of the tab part 1112. This arrangement also reduces the negative impact of the large coverage area of the first part 1131a on the connection of the tab part 1112 and external structures and reduces the negative impact of the first part 1131a on the bending performance of the tab part 1112.

[0150] For example, the width of the first part 1131a is 1 / 3 of the width of the tab part 1112, and the two first parts 1131a can cover the burrs on the end surface 1111a after being connected, so as to reduce the risk of the burrs piercing the adjacent diaphragm 12, improve the connection strength between the tab part 1112 and the first body part 1111, reduce the interference of the first part 1131a on the connection between the tab part 1112 and the external structure, and reduce the negative impact of the first part 1131a on the bending performance of the tab part 1112.

[0151] Since the insulating layer 113 is used to cover the burrs on the current collector 111, in order to reduce the negative impact of the insulating layer 113 on the energy density of the battery cell 100, the width of the insulating layer 113 should be small under the premise that the insulating layer 113 can cover the burrs. In addition, at least part of the tab part 1112 needs to be connected with the external structure (such as the electrode terminal 40) to transmit electric energy, and the insulating layer 113 located between the tab part 1112 and the adjacent external structure will interfere with the transmission of electric energy.

[0152] Therefore, the present embodiment provides that the width range of the first part 1131a covering the tab part 1112 is such that the first part 1131a can not only strengthen the connection strength between the tab part 1112 and the first body part 1111, but also reduce the negative impact of the first part 1131a on the conduction performance of the tab part 1112. In addition, the negative impact of the insulating layer 113 on the energy density of the battery cell 100 can also be reduced.

[0153] Referring to FIGS. 6-10, in some embodiments, the two sub-insulating layers 1131 have the same size in the width direction of the current collector 111. In the width direction of the current collector 111, the sizes of the first parts 1131a of the two sub-insulating layers 1131 are different, and the ratio between the sizes of the two first parts 1131a and the size of the tab part 1112 is less than or equal to 1:3.

[0154] The two sub-insulating layers 1131 have the same size in the width direction Y of the current collector 111, that is, the widths of the two sub-insulating layers 1131 are the same. In the case where the widths of the two second parts 1131b are different, the widths of the two first parts 1131a are also different, and the difference between the widths of the two first parts 1131a is the same as the difference between the widths of the two second parts 1131b. At this time, the two sub-insulating layers 1131 can have the same structure, thereby reducing the processing and manufacturing difficulty of the insulating layer 113.

[0155] The two first portions 1131a have different widths, and the widths of the two first portions 1131a relative to the width of the tab portion 1112 are both less than 1:3. In this way, the insulating layer 113 can cover the corresponding end surface 1111a, thereby reducing the risk of burrs piercing the adjacent diaphragm 12. Meanwhile, the first portion 1131a can also reduce the negative impact of the excessively large coverage area of the first portion 1131a on the connection between the tab portion 1112 and the external structure, and reduce the negative impact of the first portion 1131a on the bending performance of the tab portion 1112.

[0156] In the case where the widths of the two sub-insulating layers 1131 are different, the forming processes of the two sub-insulating layers 1131 will be different in the processing process, thereby increasing the complexity and difficulty of the forming process of the insulating layer 113. For example, in the case where the insulating layer 113 includes insulating adhesive paper, the two sub-insulating layers 1131 can both be insulating adhesive paper, and the widths of the two sub-insulating layers 1131 are different, i.e., the widths of the insulating adhesive paper are different. In this case, two different specifications of adhesive paper need to be manufactured and pasted on different sides of the current collector 111, thereby greatly increasing the complexity of the processing.

[0157] Therefore, in the embodiment, the widths of the two sub-insulating layers 1131 of the insulating layer 113 are the same, thereby reducing the difficulty of the processing and manufacturing of the insulating layer 113 and the difficulty of the insulating layer 113 being arranged on the current collector 111. Meanwhile, the two sub-insulating layers 1131 are partially staggered, thereby relieving the stress concentration of the tab 11 at the insulating layer 113.

[0158] Referring to FIGS. 6-10, in some embodiments, the tab 11 further includes an active material layer 112 arranged on the side surface 1111b. The active material layer 112 covers part of the side surface 1111b and forms a blank area 1111c on the side surface 1111b near the tab portion 1112. The second portion 1131b covers at least part of the blank area 1111c.

[0159] The active material layer 112 refers to a layered structure formed on the side surface 1111b of the current collector 111 and used to participate in an electrochemical reaction. According to the polarity of the tab 11, the material of the active material layer 112 can include lithium manganate, lithium cobaltate, lithium nickel cobalt manganese oxide, etc. The material of the active material layer 112 can also include natural graphite, artificial graphite, etc.

[0160] The blank area 1111c refers to an area on the side surface 1111b that is not covered by the active material layer 112. The blank area 1111c is formed on the side surface 1111b and located on the side of the side surface 1111b near the tab portion 1112. Referring to FIGS. 7-10, the area corresponding to the dimension L2 in the figures is the blank area 1111c.

[0161] The second part 1131b covers at least part of the blank area 1111c, that is, the second part 1131b can completely cover the blank area 1111c, or can only cover part of the blank area 1111c; for example, the second part 1131b completely covers the blank area 1111c, and at this time, the second part 1131b is attached to the active material layer 112 at the end away from the first part 1131a.

[0162] Covering the blank area 1111c by the second part 1131b can reduce the area of the first main body part 1111 directly contacting the electrolyte, thereby reducing damage of the electrolyte to the first main body part 1111, and reducing the occurrence of short circuit and the like of the battery monomer 100.

[0163] In the embodiment, the second part 1131b is capable of covering at least part of the blank area 1111c of the first main body part 1111, so as to play a role in protecting the first main body part 1111, and at the same time, the area of the first main body part 1111 exposed to the electrolyte can be reduced, thereby reducing the occurrence of short circuit and the like, and improving the safety performance of the battery monomer 100.

[0164] Referring to FIGS. 6 to 10, in some embodiments, the sub-insulating layer 1131 further includes a third part 1131c connected to the second part 1131b on the side opposite to the first part 1131a, the second part 1131b covers the blank area 1111c, and the third part 1131c covers part of the active material layer 112.

[0165] The third part 1131c is part of the sub-insulating layer 1131, and the third part 1131c is connected to the side of the second part 1131b away from the first part 1131a, that is, the first part 1131a, the second part 1131b, and the third part 1131c are arranged in sequence along the width direction Y of the current collector 111; the third part 1131c can be integrally formed with the second part 1131b, or the third part 1131c can be connected to the second part 1131b by adhesion, curing, or the like.

[0166] The third part 1131c is connected to the active material layer 112 and covers part of the active material layer 112, and since the third part 1131c is connected to the second part 1131b, at this time, the second part 1131b can completely cover the blank area 1111c, so as to better play a role in protecting the first main body part 1111, and better improve the safety performance of the battery monomer 100.

[0167] According to the structure of the third part 1131c, the third part 1131c can be connected to the active material layer 112 by adhesion, or can be connected to the active material layer 112 by curing or other means.

[0168] In the case where the sub-insulating layer 1131 does not cover the active material layer 112, the second part 1131b of the sub-insulating layer 1131 is difficult to seal and seamlessly contact the active material layer 112 due to the influence of the processing technology, and the gap between the second part 1131b and the active material layer 112 is easy to cause the first main body part 1111 to be exposed and cause short circuit and other conditions to occur.

[0169] Accordingly, the embodiment makes the sub-insulating layer 1131 further include a third part 1131c, and makes the third part 1131c cover a part of the active material layer 112, so that the second part 1131b can completely cover the blank area 1111c, thereby further improving the safety performance of the battery monomer 100.

[0170] Referring to FIGS. 6, 7, and 11, in some embodiments, the active material layer 112 includes a second main body part 1121 arranged on the side surface 1111b and a transition part 1122 connected to the second main body part 1121, the transition part 1122 is arranged on the side of the second main body part 1121 towards the blank area 1111c, and the thickness of the transition part 1122 gradually decreases along the direction from the second main body part 1121 to the blank area 1111c; the third part 1131c covers at least part of the transition part 1122.

[0171] The second main body part 1121 refers to a part of the structure of the active material layer 112, and the second main body part 1121 is mainly used for exchanging ions with the electrolyte to store and release electrical energy; the second main body part 1121 is connected to and covers most of the corresponding side surface 1111b; the transition part 1122 refers to a part of the structure of the active material layer 112, and the transition part 1122 is located on the side of the second main body part 1121 along the width direction Y of the current collector 111 towards the blank area 1111c, and the transition part 1122 is mainly used for connecting the third part 1131c to provide a fixed basis for the third part 1131c.

[0172] The thickness of the transition part 1122 gradually decreases along the direction from the second main body part 1121 to the blank area 1111c, and since the transition part 1122 is arranged on the side surface 1111b, which is a plane or substantially a plane, the surface of the transition part 1122 away from the side surface 1111b should be an arc surface or an inclined surface, so that the thickness of the transition part 1122 gradually decreases in the direction from the second main body part 1121 to the blank area 1111c; for example, the surface of the transition part 1122 away from the side surface 1111b is an inclined surface, and the inclined surface gradually approaches the side surface 1111b in the direction from the second main body part 1121 to the blank area 1111c.

[0173] The third portion 1131c covers at least part of the transition portion 1122, that is, the third portion 1131c can completely cover the transition portion 1122 or can only cover part of the transition portion 1122; because the third portion 1131c is connected to the active material layer 112, the third portion 1131c is connected to the transition portion 1122, so as to provide a fixed basis for the third portion 1131c through the transition portion 1122.

[0174] Because the thickness of the pole piece 11 at the third portion 1131c is the sum of the thickness of the current collector 111, the thickness of the two active material layers 112, and the thickness of the two third portions 1131c, in the thickness direction Z of the pole piece 11, the third portion 1131c is easy to protrude from the surface of the active material layer 112 away from the side surface 1111b, so that the thickness of the pole piece 11 at the third portion 1131c is thicker; in the winding and hot pressing process of the pole piece 11, the stress of the pole piece 11 at the third portion 1131c is correspondingly greater, and the stress concentration is more serious.

[0175] Accordingly, the active material layer 112 includes the second main portion 1121 and the transition portion 1122, the third portion 1131c covers the transition portion 1122, and the thickness of the transition portion 1122 gradually decreases; at this time, although the thickness of the pole piece 11 at the third portion 1131c is the sum of the thickness of the current collector 111, the thickness of the two transition portions 1122, and the thickness of the two third portions 1131c, the thickness of the transition portion 1122 gradually decreases, so as to reduce the height of the third portion 1131c protruding from the active material layer 112, and even to make the third portion 1131c below the surface of the active material layer 112 away from the side surface 1111b, so as to alleviate the stress concentration of the pole piece 11 at the third portion 1131c.

[0176] Because of the safety risk caused by the exposure of the blank area 1111c, the third portion 1131c needs to be arranged and cover part of the active material layer 112, so the transition portion 1122 is arranged, so that the third portion 1131c can cover at least part of the transition portion 1122, so that the second portion 1131b can better cover the blank area 1111c, and the third portion 1131c can reduce the negative impact on the thickness of the pole piece 11, so as to alleviate the stress concentration of the pole piece 11 at the third portion 1131c.

[0177] In the embodiment, the active material layer 112 includes the transition portion 1122 with gradually decreasing thickness, and the third portion 1131c covers at least part of the transition portion 1122, so as to reduce the height of the third portion 1131c protruding from the active material layer 112, thereby reducing the negative impact of the insulating layer 113 on the energy density of the battery monomer 100, and further alleviating the stress concentration of the pole piece 11 at the insulating layer 113.

[0178] Referring to FIG. 6, FIG. 7, and FIG. 11, in some embodiments, the size of the transition portion 1122 in the width direction of the current collector 111 ranges from 0.2 mm to 10 mm.

[0179] The size of the transition portion 1122 in the width direction Y of the current collector 111 is the width of the transition portion 1122, which ranges from 0.2 mm to 10 mm. For example, the width of the transition portion 1122 can be 0.2 mm, 1.2 mm, 2.2 mm, 3.2 mm, 4.2 mm, 5.1 mm, 5.2 mm, 6.2 mm, 7.2 mm, 8.2 mm, 9.2 mm, 10.0 mm, or other values.

[0180] The size of the transition portion 1122 in the width direction Y of the current collector 111 is the width of the transition portion 1122, which is positively correlated with the area of the surface of the transition portion 1122 facing away from the side surface 1111b. Since the transition portion 1122 is used to provide a fixed basis for the third portion 1131c, and the third portion 1131c covers at least part of the transition portion 1122, the greater the width of the transition portion 1122, the greater the connection area that the transition portion 1122 can provide for the third portion 1131c.

[0181] When the size of the active material layer 112 in the width direction Y of the current collector 111 is fixed, the size of the transition portion 1122 and the second main portion 1121 in the width direction Y of the current collector 111 is negatively correlated. Since the third portion 1131c covers at least part of the transition portion 1122, and the thickness of the transition portion 1122 gradually decreases, the charge and discharge performance of the active material layer 112 is mainly related to the area of the second main portion 1121, i.e., positively correlated with the size of the second main portion 1121 in the width direction Y of the current collector 111. Accordingly, under the premise that the third portion 1131c can be stably connected to the transition portion 1122, the width of the transition portion 1122 should be smaller to reduce the negative impact on the charge and discharge performance of the battery monomer 100.

[0182] For example, the width of the transition portion 1122 can be 0.2 mm. In this case, the width of the transition portion 1122 is small, the size of the second main portion 1121 in the width direction Y of the current collector 111 is large, the area of the second main portion 1121 is large, and the charge and discharge performance of the battery monomer 100 is good.

[0183] For example, the width of the transition portion 1122 can be 5.1 mm. In this case, the width of the transition portion 1122 is moderate, so that the transition portion 1122 can provide a larger connection area for the third portion 1131c, thereby enabling the third portion 1131c to be more stably connected to the transition portion 1122. At the same time, it can also make the area of the second main portion 1121 always, and the charge and discharge performance of the battery monomer 100 is good.

[0184] For example, the width of the transition portion 1122 can be 10 mm, and the width of the transition portion 1122 is relatively large, so that the transition portion 1122 can provide a larger connection area for the third portion 1131c, and the third portion 1131c can be more stably connected to the transition portion 1122.

[0185] The width of the transition portion 1122 can be in a range provided in this embodiment, so that the third portion 1131c can be more stably connected to the transition portion 1122, and the negative influence of the third portion 1131c on the charge and discharge capability of the active material layer 112 can be reduced.

[0186] Referring to FIGS. 6, 7, and 11, in some embodiments, the size of the transition portion 1122 in the width direction of the current collector 111 is in a range of 0.55 mm to 2.15 mm.

[0187] The size of the transition portion 1122 in the width direction Y of the current collector 111 is the width of the transition portion 1122, and the width is in a range of 0.2 mm to 10 mm. For example, the width can be 0.55 mm, 0.7 mm, 0.85 mm, 1 mm, 1.15 mm, 1.3 mm, 1.35 mm, 1.45 mm, 1.6 mm, 1.75 mm, 1.9 mm, 2.05 mm, 2.15 mm, or other values.

[0188] For example, the width of the transition portion 1122 can be 0.55 mm, and the width of the transition portion 1122 is relatively small, the size of the second main portion 1121 in the width direction Y of the current collector 111 is relatively large, the area of the second main portion 1121 is relatively large, and the charge and discharge performance of the battery monomer 100 is better.

[0189] For example, the width of the transition portion 1122 can be 1.35 mm, and the width of the transition portion 1122 is moderate, so that the transition portion 1122 can provide a larger connection area for the third portion 1131c, and the third portion 1131c can be more stably connected to the transition portion 1122. At the same time, the area of the second main portion 1121 is also moderate, and the charge and discharge performance of the battery monomer 100 is better.

[0190] For example, the width of the transition portion 1122 can be 2.15 mm, and the width of the transition portion 1122 is relatively large, so that the transition portion 1122 can provide a larger connection area for the third portion 1131c, and the third portion 1131c can be more stably connected to the transition portion 1122.

[0191] The embodiment further provides a length range of the transition portion 1122, and in a case where the third portion 1131c is capable of being stably connected to the transition portion 1122, the arrangement can further reduce the negative influence of the third portion 1131c on the charge and discharge capability of the active material layer 112.

[0192] Referring to FIGS. 6, 7 and 11, in some embodiments, the maximum distance between the side of the third portion 1131c facing away from the corresponding side surface 1111b and the corresponding side surface 1111b is less than or equal to the thickness of the second main body portion 1121.

[0193] The side of the third portion 1131c facing away from the side surface 1111b refers to the side of the third portion 1131c facing away from the pole piece 11, i.e., the side of the third portion 1131c facing away from the transition portion 1122, and under the condition of winding and hot pressing of the pole piece 11, the pressure can act on the side of the third portion 1131c; the maximum distance between the third portion 1131c and the corresponding side surface 1111b refers to the maximum value of the sum of the thickness of the third portion 1131c and the thickness of the transition portion 1122, and according to the structure of the third portion 1131c, the maximum distance between the third portion 1131c and the corresponding side surface 1111b can be formed between a point of the third portion 1131c facing away from the side surface 1111b and the corresponding side surface 1111b, or can be formed between the surface of the third portion 1131c facing away from the side surface 1111b and the corresponding side surface 1111b; referring to FIG. 11, the dimension denoted by H2 in the figure is the maximum distance between the side of the third portion 1131c facing away from the corresponding side surface 1111b and the corresponding side surface 1111b.

[0194] The thickness of the second main body portion 1121 refers to the dimension of the second main body portion 1121 in the thickness direction Z of the current collector 111, i.e., the distance between the side of the second main body portion 1121 facing away from the corresponding side surface 1111b and the corresponding side surface 1111b, and since the thicknesses of the portions of the second main body portion 1121 on the corresponding side surface 1111b are the same or substantially the same, the side of the second main body portion 1121 facing away from the corresponding side surface 1111b can be a plane or substantially a plane; referring to FIG. 11, the dimension denoted by H1 in the figure is the thickness of the second main body portion 1121.

[0195] The maximum distance between the side of the third part 1131c facing away from the corresponding side surface 1111b and the corresponding side surface 1111b is less than or equal to the thickness of the second main body part 1121, that is, H2≤H1. In the case where the maximum distance between the side of the third part 1131c facing away from the corresponding side surface 1111b and the corresponding side surface 1111b is less than the thickness of the second main body part 1121, the side of the third part 1131c farthest from the corresponding side surface 1111b is located between the surface of the second main body part 1121 facing away from the corresponding side surface 1111b and the corresponding side surface 1111b; in the case where the maximum distance between the side of the third part 1131c facing away from the corresponding side surface 1111b and the corresponding side surface 1111b is equal to the thickness of the second main body part 1121, the side of the third part 1131c farthest from the corresponding side surface 1111b is located on the plane where the surface of the second main body part 1121 facing away from the corresponding side surface 1111b is located.

[0196] Making the maximum distance between the side of the third part 1131c facing away from the corresponding side surface 1111b and the corresponding side surface 1111b less than or equal to the thickness of the second main body part 1121 can reduce the thickness of the pole piece 11 at the third part 1131c; in the case of winding and hot pressing of the pole piece 11, the pressure can first act on the second main body part 1121 to alleviate the stress concentration at the third part 1131c, thereby reducing damage to the pole piece 11; at the same time, this setting can also reduce the gap between the diaphragm 12 and the pole piece 11, thereby reducing the negative impact of the insulating layer 113 on the energy density of the battery monomer 100.

[0197] In the embodiment, the gap between the side of the third part 1131c facing away from the corresponding side surface 1111b and the side surface 1111b is less than the thickness of the second main body part 1121, so that the third part 1131c is difficult to protrude from the active material layer 112, thereby further reducing the negative impact of the insulating layer 113 on the energy density of the battery monomer 100 and further alleviating the stress concentration of the pole piece 11 at the insulating layer 113.

[0198] Referring to FIGS. 6, 7, and 12, in some embodiments, the sub-insulating layer 1131 includes a substrate layer 1131d and an adhesive layer 1131e provided on the substrate layer 1131d, and the adhesive layer 1131e is provided on the side of the substrate layer 1131d facing the current collector 111.

[0199] The substrate layer 1131d refers to a layered structure in the sub-insulating layer 1131 mainly used to provide a fixed basis, which can be used to provide a fixed basis for the adhesive layer 1131e and also can play a protective role for the corresponding pole piece 11; according to the role of the substrate layer 1131d, the substrate layer 1131d should have a certain strength and have a certain insulation capacity, and the material of the substrate layer 1131d can include plastic, rubber, ceramic, etc.

[0200] The adhesive layer 1131e refers to a layered structure mainly serving a fixing function in the sub-insulating layer 1131. The adhesive layer 1131e is arranged on the side of the base material layer 1131d facing the current collector 111, so as to fix the base material layer 1131d on the current collector 111. The material of the adhesive layer 1131e can include rubber, resin or other materials. The adhesive layer 1131e can be connected to the current collector 111 through light curing, thermal curing or other curing methods.

[0201] In the case where the sub-insulating layer 1131 is connected to the current collector 111, the adhesive connection can cover the end surface 1111a and wrap the burr, thereby reducing the contact between the burr and the separator 12. The base material layer 1131d can further reduce the contact between the burr and the separator 12. Meanwhile, the base material layer 1131d can also protect the current collector 111 and reduce the damage that other structures may cause to the current collector 111.

[0202] The embodiments provide some structures of the sub-insulating layer 1131, so that the sub-insulating layer 1131 includes the adhesive layer 1131e and the base material layer 1131d. The base material layer 1131d can be connected to the current collector 111 through the adhesive layer 1131e, and can wrap the burr on the end surface 1111a through the adhesive layer 1131e. The burr is difficult to pierce the insulating layer 113 through the base material layer 1131d. Meanwhile, the base material layer 1131d can also protect the current collector 111.

[0203] In some embodiments, the base material layer 1131d is an insulating structural layer.

[0204] The base material layer 1131d is an insulating structural layer, i.e., the material of the base material layer 1131d includes an insulating material. The insulating layer 113 can better separate the current collector 111 covered thereby and the external environment (e.g., the electrolyte or the adjacent other pole piece 11), so as to protect the current collector 111 and reduce the short circuit of the current collector 111. For example, the material of the base material layer 1131d can include polypropylene.

[0205] In the embodiments, the base material layer 1131d is an insulating structural layer, so as to reduce the risk of short circuit of the current collector 111.

[0206] In some embodiments, the thickness of the base material layer 1131d ranges from 6 μm to 20 μm.

[0207] The thickness of the base material layer 1131d is the dimension of the base material layer 1131d in the arrangement direction of the base material layer 1131d and the adhesive layer 1131e. The dimension ranges from 6 μm to 20 μm. For example, the dimension can be 6 μm, 8 μm, 10 μm, 12 μm, 14 μm, 16 μm, 18 μm, 20 μm or other values.

[0208] For example, the thickness of the substrate layer 1131d can be 6 μm. In this case, the thickness of the substrate layer 1131d is thin, so that the negative effect of the sub-insulating layer 1131 on the energy density of the battery cell 100 is small.

[0209] For example, the thickness of the substrate layer 1131d can be 13 μm. In this case, the substrate layer 1131d has a certain thickness, so that the substrate layer 1131d can not only protect the current collector 111, but also reduce the risk of the burr piercing the insulating layer 113 and the adjacent separator 12; at the same time, the negative effect of the sub-insulating layer 1131 on the energy density of the battery cell 100 is reduced.

[0210] For example, the thickness of the substrate layer 1131d can be 20 μm. In this case, the thickness of the substrate layer 1131d is thick, so that the substrate layer 1131d can better protect the current collector 111 and better reduce the risk of the burr piercing the insulating layer 113 and the adjacent separator 12.

[0211] The embodiment provides a thickness range of the substrate layer 1131d, so that the burr is difficult to pierce the substrate layer 1131d, and the substrate layer 1131d can protect the current collector 111; the setting also makes the substrate layer 1131d not easy to be punctured by static electricity, so that the substrate layer 1131d can better protect the current collector 111.

[0212] In some embodiments, the adhesive layer 1131e is a sticky structure layer.

[0213] The adhesive layer 1131e is a sticky structure layer, that is, the material of the adhesive layer 1131e includes a sticky material, so that the adhesive layer 1131e can bond the substrate layer 1131d to the current collector 111, and the substrate layer 1131d is not easy to separate from the current collector 111, so that the substrate layer 1131d can better and more stably protect the current collector 111; at the same time, the adhesion of the adhesive layer can also provide resistance for the burr to pierce the insulating layer 113, so that the burr is more difficult to pierce the insulating layer 113; for example, the material of the adhesive layer 1131e includes polyacrylate.

[0214] It can be understood that, in the case where the sub-insulating layer 1131 includes the first part 1131a, the second part 1131b and the third part 1131c, at least part of the adhesive layer 1131e of the first part 1131a is bonded to the adhesive layer 1131e of another first part 1131a, the adhesive layer 1131e of the second part 1131b is bonded to the blank area 1111c of the current collector 111, and the adhesive layer 1131e of the third part 1131c is bonded to the transition part 1122 of the active material layer 112.

[0215] In this embodiment, the adhesive layer 1131e is a sticky structure layer, which is used to bond the substrate layer 1131d to the current collector 111 and / or the active material layer 112; at the same time, the adhesive layer 1131e can also cover the burrs on the end face 1111a, so as to reduce the risk that the burrs pierce the insulating layer 113.

[0216] In some embodiments, the thickness of the adhesive layer 1131e ranges from 3 μm to 10 μm.

[0217] The thickness of the adhesive layer 1131e is the dimension of the adhesive layer 1131e in the arrangement direction of the adhesive layer 1131e and the substrate layer 1131d, which ranges from 3 μm to 10 μm; for example, the dimension can be 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, or other values.

[0218] For example, the thickness of the adhesive layer 1131e can be 3 μm, in which case the adhesive layer 1131e is relatively thin, so that the negative impact of the sub-insulating layer 1131 on the energy density of the battery cell 100 is relatively small.

[0219] For example, the thickness of the adhesive layer 1131e can be 7 μm, in which case the adhesive layer 1131e has a certain thickness, so that the adhesive layer 1131e can not only fix the substrate layer 1131d, but also cover the burrs to reduce the risk that the burrs pierce the insulating layer 113 and the adjacent separator 12; at the same time, the negative impact of the sub-insulating layer 1131 on the energy density of the battery cell 100 can also be reduced.

[0220] For example, the thickness of the adhesive layer 1131e can be 10 μm, in which case the adhesive layer 1131e is relatively thick, so that the adhesive layer 1131e can better fix the substrate layer 1131d, and can better cover the burrs to reduce the risk that the burrs pierce the insulating layer 113 and the adjacent separator 12.

[0221] The embodiments provide some thickness ranges of the adhesive layer 1131e, so that the adhesive layer 1131e can more stably bond the substrate layer 1131d to the current collector 111 and / or the active material layer 112, and at the same time, the adhesive layer 1131e can also hinder the burrs from piercing the insulating layer 113.

[0222] In some embodiments, the peeling strength of the insulating layer 113 ranges from 15 N / m (Newton per meter) to 20 N / m.

[0223] The peeling strength of the insulation layer 113 refers to the force required to peel the unit width insulation layer 113 from the current collector 111, and the peeling strength of the insulation layer 113 reflects the adhesion strength of the insulation layer 113 to the current collector 111 and can also reflect the adhesion stability of the insulation layer 113 in the electrolyte; the peeling strength of the insulation layer 113 ranges from 15 N / m to 20 N / m, and examples can be 15 N / m, 16 N / m, 17 N / m, 18 N / m, 19 N / m, 20 N / m or other values.

[0224] Examples, the peeling strength of the insulation layer 113 ranges from 15 N / m to 20 N / m after the insulation layer 113 is soaked in the electrolyte for 1000 hours, so that the insulation layer 113 can be stably connected to the current collector 111, thereby reducing the risk of short circuit of the pole piece 11 caused by the insulation layer 113 being separated.

[0225] For testing the peeling strength of the insulation layer 113, the insulation layer 113 can be adhered to a sample (such as a copper foil) having the same size and material as the current collector 111; then the sample with the insulation layer 113 adhered thereto is soaked in the electrolyte for a period of time and taken out, and the soaking time can be set as needed (for example, 1000 hours); then the soaked sample is adhered to a stainless steel plate and compacted so that the sample can be stably adhered to the stainless steel plate; then one end of the insulation layer 113 is clamped by a tensile testing machine and pulled up at a preset stable speed until the insulation layer 113 is separated from the sample, and the displacement and force during the process are recorded by the tensile testing machine.

[0226] Examples, the insulation layer 113 is an insulation adhesive tape with a thickness of 13 μm and a width of 8 mm, and the sample is an aluminum foil with a thickness of 13 μm, and the insulation adhesive tape is adhered to the aluminum foil; the aluminum foil with the adhered insulation adhesive tape is soaked in the electrolyte at 70°C for 200h, 400h, 600h, 800h and 1000h respectively and then taken out, at which time the insulation adhesive tape does not fall off; a high-iron tensile testing machine is used to adhere the aluminum foil after soaking to a stainless steel plate with double-sided adhesive tape, one side of the insulation adhesive tape faces outward and is compacted with a compression roller to fix the entire sample on the tensile testing machine; the tensile testing machine is used to clamp one end of the adhesive tape and pull it up at a speed of 50 mm / min until the adhesive tape is completely peeled off from the aluminum foil, and the displacement and force during the process are recorded; when the base material layer 1131d of the insulation adhesive tape is polypropylene with a thickness of 10 μm and the adhesive layer 1131e is polyacrylate with a thickness of 3 μm, the peeling strength of the insulation adhesive tape is 19.21 N / m.

[0227] The embodiment provides a range of peel strength of the insulation layer 113, so that the insulation layer 113 is difficult to separate from the current collector 111 and / or the active material layer 112, thereby enabling the insulation layer 113 to still have strong connection stability in an electrolyte wet environment.

[0228] In some embodiments, the needle penetration strength of the insulation layer 113 is greater than or equal to 300 gf (gram force).

[0229] The needle penetration strength of the insulation layer 113 refers to the bearing capacity or the ability to resist puncture damage of the insulation layer 113 under the action of needle penetration. The needle penetration strength of the insulation layer 113 reflects the ability of the insulation layer 113 to resist puncture by burrs, and also reflects the protection ability of the insulation layer 113 to the current collector 111. The needle penetration strength of the insulation layer 113 is greater than or equal to 300 gf. For example, the needle penetration strength can be 300 gf, 500 gf, 800 gf, 1000 gf or other values.

[0230] For example, the needle penetration strength of the insulation layer 113 can be 300 gf, so that the burr is not easy to pierce the insulation layer 113, so that the insulation layer 113 can better reduce the risk of short circuit of the pole piece 11 caused by the puncture of the burr to the diaphragm 12. At the same time, the requirement for the material of the insulation layer 113 is not too high, thereby reducing the processing cost and processing difficulty of the insulation layer 113.

[0231] For the test of the needle penetration strength of the insulation layer 113, a steel needle can be used to test on a puncture tester, and the force of the steel needle to pierce the insulation layer 113 at a certain speed is recorded.

[0232] For example, the insulation layer 113 is an insulation adhesive tape with a thickness of 13 μm and a length and a width of 50 mm. A steel needle with a diameter of 1 mm is used to test on a puncture tester, and the force of the insulation adhesive tape to pierce at a speed of 50 mm / min is recorded. In the case that the base material layer 1131d of the insulation adhesive tape is polypropylene with a thickness of 10 μm and the adhesive layer 1131e is polyacrylate with a thickness of 3 μm, ten insulation adhesive tapes with the same specifications are tested for puncture, and the average puncture strength of the insulation adhesive tape is 425.31 gf.

[0233] The embodiment provides a range of needle penetration strength of the insulation layer 113, so that the burr is difficult to pierce the insulation layer 113, thereby enabling the insulation layer 113 to better reduce the risk of short circuit of the adjacent pole piece 11 by the burr.

[0234] In some embodiments, the battery monomer 100 further comprises an electrode assembly 10, the electrode assembly 10 comprising a positive pole piece 114, a diaphragm 12 and a negative pole piece 115 arranged in sequence and spaced apart. The pole piece 11 is the positive pole piece 114.

[0235] The pole piece 11 is a positive pole piece 114, at this time the current collector 111 can be an aluminum foil, the active material layer 112 can include cobalt, nickel, manganese, lithium iron phosphate, etc., the insulating layer 113 is arranged on the end surface 1111a of the first main body part 1111 close to the tab part 1112, and the insulating layer 113 covers part of the tab part 1112.

[0236] For example, in the case of the pole piece 11 being the positive pole piece 114, the insulating layer 113 includes a first part 1131a, a second part 1131b and a third part 1131c connected in sequence, wherein the first part 1131a extends to outside the current collector 111 and covers part of the tab part 1112, the second part 1131b covers the blank area 1111c of the current collector 111, and the third part 1131c covers the transition part 1122 of the active material layer 112.

[0237] The burr generated by processing of the positive pole piece 114 is more dangerous when short-circuited with the active material layer 112 of the negative pole piece 115; accordingly, the pole piece 11 is the positive pole piece 114 in this embodiment to reduce the safety risk caused by burr short-circuiting.

[0238] In some embodiments, the preparation process of the positive pole piece 114 is as follows:

[0239] The material of the active material layer 112 of the positive pole piece 114 includes active material lithium iron phosphate (LiFePO4, LFP), binder polyvinylidene fluoride (PVDF) and conductive carbon black (Super P), which are uniformly mixed in a ratio of lithium iron phosphate: polyvinylidene fluoride: conductive carbon black = 95:3:2 to obtain a first mixed slurry.

[0240] The dispersion solvent is 1-methyl-2-pyrrolidone (NMP), and the first mixed slurry is dispersed using the dispersion solvent to obtain a positive pole slurry.

[0241] The positive pole slurry is coated on both sides 1111b of the aluminum foil (current collector 111 of the positive pole piece 114), and is sequentially subjected to drying, rolling, die cutting and slitting.

[0242] The insulating adhesive paper is used as the sub-insulating layer 1131, and two insulating adhesive papers are respectively attached to the die-cut edges on both sides of the aluminum foil, and the portions of the two insulating adhesive papers are attached to each other and form the insulating layer 113; the widths of the portions of the two insulating adhesive papers covering the corresponding active material layer 112 are 0.2mm and 0.8mm respectively.

[0243] In some embodiments, the preparation process of the negative pole piece 115 is as follows:

[0244] The material of the active material layer 112 of the negative electrode sheet 115 includes an active material graphite, a binder styrene butadiene rubber (SBR), and conductive carbon black, which are uniformly mixed in a ratio of graphite: styrene butadiene rubber: conductive carbon black = 94:4:2 to obtain a second mixed slurry.

[0245] The dispersion solvent is ionized water, and the second mixed slurry is dispersed using the dispersion solvent to obtain a negative electrode slurry.

[0246] The negative electrode slurry is coated on both sides 1111b of the copper foil (current collector 111 of the negative electrode sheet 115), and is sequentially subjected to drying, rolling, die cutting, and slitting to obtain the negative electrode sheet 115.

[0247] In some embodiments, the sub-insulating layer 1131 is an insulating adhesive tape, the base material layer 1131d of which is made of polypropylene (PP) and has a thickness of 10 μm; the adhesive layer 1131e is made of polyacrylate (PA) and has a thickness of 3 μm; the total thickness of the sub-insulating layer 1131 is 13 μm, and the size of the sub-insulating layer 1131 in the width direction Y of the current collector 111 is 8 mm.

[0248] In some embodiments, the base film of the separator 12 has a thickness of 7 μm and is made of polypropylene.

[0249] In some embodiments, the electrode assembly 10 is prepared as follows:

[0250] The prepared positive electrode sheet 114, the separator 12, and the negative electrode sheet 115 are wound, and then are subjected to heat pressing to obtain the electrode assembly 10.

[0251] In some embodiments, the electrolyte is prepared as follows:

[0252] Lithium hexafluorophosphate (LFPF6) is sequentially added to ethylene carbonate (EC) to control the mass fraction of the lithium hexafluorophosphate in the electrolyte to be 12.5%, to obtain the electrolyte.

[0253] In some embodiments, the battery cell 100 is assembled as follows:

[0254] The electrode assembly 10 is placed in the shell 20 (for example, an aluminum shell) of the outer package, the tab portions 1112 of the positive electrode sheet 114 and the negative electrode sheet 115 are welded to the electrode terminals 40 of the end cover 30, and are subjected to drying; the prepared electrolyte is injected into the shell 20, and then is subjected to standing, formation, and capacity distribution to complete the preparation of the battery device 1000.

[0255] In some embodiments, the battery cell 100 comprises a tab 11, the tab 11 comprising a current collector 111, an active material layer 112, and an insulating layer 113.

[0256] The current collector 111 comprises a first main body part 1111, the first main body part 1111 comprising two side surfaces 1111b and two end surfaces 1111a, the end surfaces 1111a being prone to burrs; the current collector 111 further comprises a tab part 1112 connected to the end surfaces 1111a.

[0257] The active material layer 112 comprises a second main body part 1121 and a transition part 1122 connected to the second main body part 1121, the transition part 1122 being located on a side of the second main body part 1121 facing the tab part 1112, and the thickness of the transition part 1122 gradually decreases in a direction in which the second main body part 1121 points to the tab part 1112; a part of the current collector 111 not covered by the active material layer 112 is a blank area 1111c, the blank area 1111c being located on the side surface 1111b of the first main body part 1111 and close to the tab part 1112.

[0258] The insulating layer 113 comprises two sub-insulating layers 1131 connected to the two side surfaces 1111b respectively; the sub-insulating layer 1131 comprises a first part 1131a, a second part 1131b, and a third part 1131c connected in sequence. The first part 1131a extends out of the current collector 111 and covers a part of the tab part 1112, and the first part 1131a can also be connected to another first part 1131a to cover the corresponding end surface 1111a and the burrs; the second part 1131b covers the blank area 1111c of the current collector 111, and the third part 1131c covers at least part of the transition part 1122.

[0259] In the two sub-insulating layers 1131, the widths of the two first parts 1131a are different, and the widths of the two third parts 1131c are also different.

[0260] The insulating layer 113 comprises a base material layer 1131d and an adhesive layer 1131e, one side of the adhesive layer 1131e being connected to the current collector 111, and the other side being connected to the base material layer 1131d.

[0261] In the second aspect, some embodiments of the present application provide a battery device 1000, comprising the battery cell 100 provided by some embodiments of the first aspect; in the battery device 1000, the burrs of the tab 11 are less likely to pierce the adjacent separator 12 and cause short circuit, so that the battery device 1000 can have higher stability.

[0262] In a third aspect, some embodiments of the present application further provide an energy storage device 1 comprising the battery cell 100 provided by some embodiments of the first aspect, or the battery device 1000 provided by some embodiments of the second aspect.

[0263] The energy storage device 1 comprises one or more battery clusters to improve the voltage and capacity of the energy storage device 1. The battery cluster can comprise a plurality of battery devices 1000, which are connected in series by busbar components to improve the voltage of the energy storage device 1. When the energy storage device 1 comprises a plurality of battery clusters, the plurality of battery clusters are connected in parallel to improve the capacity of the energy storage device 1.

[0264] The energy storage device 1 can be used in energy storage power stations, wind power systems, solar power systems, mobile power systems, or temporary power supply systems, etc. The energy storage device 1 can store electrical energy as needed and output electrical energy at an appropriate time. For example, the energy storage device 1 can store electrical energy during the off-peak period of electricity consumption, and provide electrical energy for related users or electrical equipment during the peak period of electricity consumption. The energy storage system provided by the embodiments of the present application can be any power system that needs to use the energy storage device 1.

[0265] In some embodiments, the energy storage device 1 is an energy storage container or an energy storage cabinet.

[0266] In some embodiments, the energy storage device 1 can comprise a cabinet body and one or more battery clusters, which are accommodated in the cabinet body.

[0267] In some embodiments, the energy storage device 1 can comprise a thermal management module, a master control module, a general control module, a power distribution module, and a fire-fighting module, etc.

[0268] As an example, the thermal management module can comprise a liquid cooling unit, which provides cooling liquid for adjusting the temperature of the battery cell 100 to each battery device 1000 through a pipeline.

[0269] As an example, the master control module can serve as a battery management unit of the battery cluster, for monitoring and managing the battery cluster. The master control module can monitor the current, voltage, power, or temperature, etc. of the battery cluster. For example, the charging and discharging current, voltage, etc. of the battery cluster can be controlled. The master control module comprises a slave battery management unit (SBMU), a fuse switch, and other modules.

[0270] As an example, the master control module can be used as a battery management unit of the energy storage device 1 to monitor and manage the energy storage device 1. The master control module can monitor information such as current, voltage, power, state of charge, or temperature of the energy storage device 1. For example, the charging and discharging current, voltage, and the like of the energy storage device 1 can be controlled. As an example, the master control module includes an insulation monitoring module IMM (Insulation Monitoring Module, IMM), a master battery management unit MBMU (Master Battery Management Unit, MBMU), an Ethernet ETH (EtherNet, ETH), and an optical fiber conversion module.

[0271] As an example, the fire control module includes a control panel, a detector, an alarm device, and the like, which are used for detecting, alarming, or extinguishing the energy storage system.

[0272] As an example, the power distribution module can be used to distribute power to the modules that need power in the energy storage device 1.

[0273] In a fourth aspect, referring to FIG. 13, some embodiments of the present application further provide an energy storage system, which includes the power conversion device 2 and the energy storage device 1 provided by some embodiments of the third aspect. The power conversion device 2 is used to electrically connect the power generation device 3 and the energy storage device 1.

[0274] The energy storage system can include one or more energy storage devices 1 and a power conversion device 2 (Power Converter System, PCS) connected between the power generation device 3 and the energy storage device 1. The power generation device 3 is used to generate electric energy, and the electric energy generated by the power generation device 3 can be stored in the energy storage device 1 through the power conversion device 2. As an example, the power generation device 3 can be a solar panel, a water power generation device, a fire power generation device, a wind power generation device, and the like. The specific type of the power generation device 3 is not limited in the present application.

[0275] In a fifth aspect, some examples of the present application further provide a power consumption device, which includes the battery cell 100 provided by some embodiments of the first aspect, or the battery device 1000 provided by some embodiments of the second aspect, or the energy storage device 1 provided by some embodiments of the third aspect, or the energy storage system provided by some embodiments of the fourth aspect. The battery cell 100 or the battery device 1000 is used to store or provide electric energy.

[0276] In a sixth aspect, referring to FIG. 14, some embodiments of the present application further provide a charging network, which includes the charging pile 4 and the energy storage device 1 provided by some embodiments of the third aspect, or the energy storage system provided by some embodiments of the fourth aspect. The energy storage device 1 or the energy storage system is used to provide electric energy for the charging pile 4.

[0277] The charging pile 4 is electrically connected with the energy storage device 1, and the energy storage device 1 is used to provide electric energy for the charging pile 4. The charging pile 4 is electrically connected with the battery device 1000 in the energy storage device 1 through a cable, and the battery device 1000 can provide the stored electric energy to the charging pile 4. The charging pile 4 has one or more connectors 5, which are used to connect with the electric equipment (such as a vehicle), so as to supply electric energy to the electric equipment.

[0278] The energy storage device 1 can be located inside the charging pile 4 (for example, a charging and storage integrated machine), or outside the charging pile 4.

[0279] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part 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 be covered in the scope of the claims and the specification of the present application. Especially, as long as there is no structural conflict, each technical feature 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 falling within the scope of the claims.

Claims

1. A battery cell, characterized by, The pole piece comprises: a current collector comprising two end faces located at opposite ends along a width direction of the current collector, and two side faces located at opposite sides along a thickness direction of the current collector; an insulating layer provided on the current collector, the insulating layer covering the end faces, and covering portions of the two side faces and forming a first covering face and a second covering face respectively; in the same projection plane perpendicular to the thickness direction of the current collector, the size of the orthographic projection of the first covering face in the width direction of the current collector is different from the size of the orthographic projection of the second covering face in the width direction of the current collector.

2. The battery cell of claim 1, wherein, in the same projection plane perpendicular to the thickness direction of the current collector, the difference between the size of the orthographic projection of the first covering face in the width direction of the current collector and the size of the orthographic projection of the second covering face in the width direction of the current collector is less than or equal to 1 mm.

3. The battery cell according to claim 1 or 2, characterized in that, The current collector comprises a first body portion and a tab portion connected to the first body portion, the side faces and the end faces are formed on the first body portion, and the tab portion extends from any one of the two end faces in the width direction of the current collector towards a direction away from the first body portion; The insulating layer covers at least a portion of the tab portion, and the insulating layer also covers the end face connected to the tab portion.

4. The battery cell of claim 3, wherein, The insulating layer comprises two sub-insulating layers corresponding to the two side faces, the sub-insulating layer comprises a first portion and a second portion connected to the first portion, and the second portion is connected to the side face, and the first covering face and the second covering face are respectively the faces of the two second portions connected to the corresponding side faces; At least a portion of the first portion is connected to the first portion of another adjacent sub-insulating layer to cover the corresponding end face, and at least a portion of the first portion covers at least a portion of the tab portion.

5. The battery cell of claim 4, wherein, In the width direction of the current collector, the ratio between the size of the first portion and the size of the tab portion is less than or equal to 1:

3.

6. The battery cell according to claim 4 or 5, characterized in that The sizes of the two sub-insulating layers in the width direction of the current collector are the same; In the width direction of the current collector, the sizes of the first portions of the two sub-insulating layers are different, and the ratio between the size of each of the first portions and the size of the tab portion is less than or equal to 1:

3.

7. The battery cell of any one of claims 4-6, wherein, The pole piece further comprises an active material layer provided on the side face, the active material layer covers a portion of the side face, and forms a blank area on the side face close to the tab portion, and the second portion covers at least a portion of the blank area.

8. The battery cell of claim 7, wherein, The sub-insulating layer further comprises a third portion connected to the second portion on the opposite side of the first portion, the second portion covers the blank area, and the third portion covers a portion of the active material layer.

9. The battery cell of claim 8, wherein, The active material layer comprises a second body portion provided on the side face and a transition portion connected to the second body portion, the transition portion is provided on the side of the second body portion towards the blank area, and the thickness of the transition portion gradually decreases in the direction from the second body portion to the blank area; The third portion covers at least a portion of the transition portion.

10. The battery cell of claim 9, wherein, The size of the transition portion ranges from 0.2 mm to 10 mm in the width direction of the current collector.

11. The battery cell according to claim 9 or 10, characterized in that The size of the transition portion ranges from 0.55 mm to 2.15 mm in the width direction of the current collector.

12. The battery cell of any one of claims 9-11, wherein, The maximum distance between the side of the third portion facing away from the corresponding side and the corresponding side is less than or equal to the thickness of the second main body portion.

13. The battery cell of any one of claims 4-12, wherein, The sub-insulating layer comprises a substrate layer and an adhesive layer disposed on the substrate layer, and the adhesive layer is disposed on the side of the substrate layer facing the current collector.

14. The battery cell of claim 13, wherein, The substrate layer is an insulating structural layer.

15. The battery cell according to claim 13 or 14, characterized in that The thickness of the substrate layer ranges from 6 μm to 20 μm.

16. The battery cell of any one of claims 13-15, wherein, The adhesive layer is an adhesive structural layer.

17. The battery cell of any one of claims 13-16, wherein, The thickness of the adhesive layer ranges from 3 μm to 10 μm.

18. The battery cell of any one of claims 1-17, wherein, The peeling strength of the insulating layer ranges from 15 N / m to 20 N / m.

19. The battery cell of any one of claims 1-18, wherein, The needle-punching strength of the insulating layer is greater than or equal to 300 gf.

20. The battery cell of any one of claims 1-19, wherein, The battery cell further comprises an electrode assembly, the electrode assembly comprising a positive electrode sheet, a separator and a negative electrode sheet arranged in sequence with intervals; The electrode sheet is the positive electrode sheet.

21. A battery device, characterized by The battery cell as claimed in any one of claims 1-20.

22. An energy storage device, comprising: The battery device as claimed in claim 21. The battery cell or the battery device is used for storing or providing electric energy.

23. An energy storage system characterized by, The energy storage device as claimed in claim 22.

24. An electrical device, comprising: The battery cell as claimed in any one of claims 1-20, the battery device as claimed in claim 21, the energy storage device as claimed in claim 22 or the energy storage system as claimed in claim 23 is used for storing or providing electric energy.

25. A charging network characterized by, The charging pile and the energy storage device as claimed in claim 22, or the energy storage system as claimed in claim 23. The energy storage device or the energy storage system is used for providing electric energy for the charging pile.

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