Cylindrical battery cells, batteries and electrical devices

Abstract

This application discloses a cylindrical battery cell, a battery, and an electrical device. The cylindrical battery cell includes a casing and an electrode assembly. The diameter of the cylindrical battery cell is greater than or equal to 40 mm. At least a portion of the electrode assembly is housed within the casing. The electrode assembly includes a positive electrode, a negative electrode, and a separator, which are wound together, with the separator separating the positive and negative electrodes. The negative electrode active material of the negative electrode includes at least one of silicon and carbon. A gap is formed between the positive and negative electrodes, extending along the winding direction of the electrode assembly, and the radial dimension of the gap is 5 μm to 60 μm.

Description

Cylindrical battery cell, battery and electric device TECHNICAL FIELD

[0001] The present application relates to the technical field of batteries, and more particularly, to a cylindrical battery cell, a battery and an electric device. BACKGROUND

[0002] Battery cells, particularly cylindrical battery cells, are widely used in electronic devices, such as mobile phones, notebook computers, electric vehicles, electric cars, electric planes, electric ships, electric toy cars, electric toy ships, electric toy planes and electric tools, etc.

[0003] With the gradual increase of the requirement for energy density, the diameter of the cylindrical battery cell gradually increases. However, with the gradual increase of the diameter of the cylindrical battery cell, the expansion force of the cylindrical battery cell in the cycle process is also greater, and the expansion force will affect the cycle performance of the cylindrical battery cell. How to improve the cycle performance of the cylindrical battery cell with large diameter is an important research direction in the technical field of batteries.

[0004] SUMMARY

[0005] The present application provides a cylindrical battery cell, a battery and an electric device, which can improve the reliability.

[0006] In a first aspect, the present application provides a cylindrical battery cell with a diameter ≥ 40 mm, comprising a shell and an electrode assembly. At least part of the electrode assembly is accommodated in the shell. The electrode assembly comprises a positive electrode sheet, a negative electrode sheet and a separator, the positive electrode sheet, the negative electrode sheet and the separator are wound and arranged, and the separator separates the positive electrode sheet and the negative electrode sheet. The negative electrode active material of the negative electrode sheet comprises at least one of a silicon-based material and a carbon-based material. A gap is formed between the positive electrode sheet and the negative electrode sheet, the gap extends along the winding direction of the electrode assembly, and the radial dimension of at least part of the gap is 5 μm-60 μm.

[0007] In the cycle process of the cylindrical battery cell, the gap can provide space for the expansion of the negative electrode sheet; the present application limits the radial dimension of at least part of the gap to be greater than or equal to 5 μm, which can reduce the extrusion of the electrolyte in the internal pores of the positive electrode film layer of the positive electrode sheet and the internal pores of the negative electrode film layer of the negative electrode sheet, can reduce the concentration difference of the electrolyte in each region inside the electrode sheet, and improve the cycle performance of the cylindrical battery cell with a larger diameter. The gap can reduce the expansion amount of the electrode assembly, thereby reducing the extrusion effect on the shell, reducing the risk of deformation and cracking of the shell, and improving the reliability of the cylindrical battery cell. The present application limits the radial dimension of at least part of the gap to be less than or equal to 60 μm, so as to shorten the ion migration path between the positive electrode sheet and the negative electrode sheet, reduce the internal resistance of the cylindrical battery cell, reduce the heat generation, and reduce the influence of the gap on the energy density.

[0008] In some embodiments, at least one of the positive electrode sheet, the negative electrode sheet, and the separator includes a base and a plurality of support portions provided on the base. The base has two first surfaces oppositely arranged along a thickness direction of the base, and the plurality of support portions are protruded from at least one of the first surfaces to form a gap between the positive electrode sheet and the negative electrode sheet. By providing the plurality of protruded support portions, the gap between the positive electrode sheet and the negative electrode sheet can be increased, more space for expansion of the negative electrode sheet can be provided, and the cycle performance of the cylindrical battery cell can be improved.

[0009] In some embodiments, the support portions are configured to be compressible. During the cycle of the cylindrical battery cell, the support portions can be compressed when pressed, thereby providing more space for expansion of the negative electrode sheet. The compressible support portions can release stress by deforming under compression, thereby reducing the risk of the positive electrode sheet or the negative electrode sheet being pressed by the support portions and improving reliability.

[0010] In some embodiments, the plurality of support portions include first support portions and second support portions, the first support portions protruding from the first surfaces to a height greater than a height at which the second support portions protrude from the first surfaces.

[0011] The first support portions have a greater height, which can support the positive electrode sheet or the negative electrode sheet to form a larger gap, thereby providing more space for expansion of the negative electrode sheet. The second support portions have a smaller height, which occupies less space. As the negative electrode sheet expands, the gap gradually decreases; the second support portions can be pressed only after the negative electrode sheet expands to a certain extent, thereby reducing the pressure on the negative electrode sheet in the early stage of expansion. When the second support portions are pressed, the second support portions can slow down the expansion of the negative electrode sheet to some extent, reduce the electrolyte squeezed out by the negative electrode sheet, and improve the cycle performance of the cylindrical battery cell.

[0012] In some embodiments, at least one of the positive electrode sheet, the negative electrode sheet, and the separator includes a plurality of organic particles, and the support portions include the organic particles. The organic particles can support the positive electrode sheet or the negative electrode sheet to form a gap. When thermal runaway occurs in the cylindrical battery cell, the organic particles can form a gel film structure at high temperature, thereby reducing the diffusion channel of active ions and delaying the time of thermal spread, thereby improving the reliability of the cylindrical battery cell.

[0013] In some embodiments, the plurality of organic particles include first organic particles and second organic particles, and the first organic particles have a number average particle size greater than a number average particle size of the second organic particles. The first organic particles with a larger number average particle size can support the positive electrode sheet or the negative electrode sheet to form a larger gap, thereby providing more space for expansion of the negative electrode sheet. The second organic particles with a smaller number average particle size can be pressed only after the negative electrode sheet expands to a certain extent, thereby reducing the pressure on the negative electrode sheet in the early stage of expansion. When the second organic particles are pressed, the second organic particles can slow down the expansion of the negative electrode sheet to some extent, reduce the electrolyte squeezed out by the negative electrode sheet, and improve the cycle performance of the cylindrical battery cell.

[0014] In some embodiments, the plurality of organic particles includes first organic particles including one or more of a homopolymer or copolymer of a fluorine-containing alkenyl monomer unit, a homopolymer or copolymer of an olefin monomer unit, a homopolymer or copolymer of an unsaturated nitrile monomer unit, a homopolymer or copolymer of an alkylene oxide monomer unit, and a modified compound of each of the above homopolymers or copolymers.

[0015] In some embodiments, the first organic particles include one or more of polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinyl fluoride, polyvinylidene fluoride, polyethylene, polypropylene, polyacrylonitrile, polyethylene oxide, a copolymer of different fluorine-containing alkenyl monomer units, a copolymer of a fluorine-containing alkenyl monomer unit and an olefin monomer unit, a copolymer of a fluorine-containing alkenyl monomer unit and an acrylic monomer unit, a copolymer of a fluorine-containing alkenyl monomer unit and an acrylate monomer unit, and a modified compound of each of the above homopolymers or copolymers.

[0016] In some embodiments, the plurality of organic particles includes second organic particles including one or more of a homopolymer or copolymer of an acrylate monomer unit, a homopolymer or copolymer of an acrylic monomer unit, a homopolymer or copolymer of a styrene monomer unit, a polyurethane compound, a rubber compound, and a modified compound of each of the above homopolymers or copolymers.

[0017] In some embodiments, the second organic particles include one or more of a copolymer of an acrylate monomer unit and a styrene monomer unit, a copolymer of an acrylic monomer unit and a styrene monomer unit, a copolymer of an acrylic monomer unit-acrylate monomer unit-styrene monomer unit, a copolymer of a styrene monomer unit and an unsaturated nitrile monomer unit, a copolymer of a styrene monomer unit-olefin monomer unit-unsaturated nitrile monomer unit, and a modified compound of each of the above copolymers.

[0018] In some embodiments, the plurality of supports includes first supports and second supports, the first supports protruding from the first surface to a height greater than a height to which the second supports protrude from the first surface. The plurality of organic particles includes first organic particles and second organic particles; the first supports include the first organic particles, and the second supports include the second organic particles.

[0019] By providing the first organic particles and the second organic particles having different number average particle diameters, the first supports and the second supports having different heights can be formed. The first supports have a greater height, which can support the positive electrode sheet or the negative electrode sheet to form a larger gap, thereby providing more space for the expansion of the negative electrode sheet.

[0020] In some embodiments, the side of the positive electrode sheet facing the separator is provided with a plurality of support portions, the side of the separator facing the positive electrode sheet is provided with a plurality of support portions, and the plurality of support portions of the positive electrode sheet facing the separator and the plurality of support portions of the separator facing the positive electrode sheet are at least partially arranged opposite to each other. By arranging the plurality of support portions of the positive electrode sheet and the plurality of support portions of the separator to face each other, the plurality of support portions of the positive electrode sheet and the plurality of support portions of the separator can at least partially abut each other, so as to increase the gap and provide more space for the expansion of the negative electrode sheet.

[0021] In some embodiments, the side of the negative electrode sheet facing the separator is provided with a plurality of support portions, the side of the separator facing the negative electrode sheet is provided with a plurality of support portions, and the plurality of support portions of the negative electrode sheet facing the separator and the plurality of support portions of the separator facing the negative electrode sheet are at least partially arranged opposite to each other. By arranging the plurality of support portions of the negative electrode sheet and the plurality of support portions of the separator to face each other, the plurality of support portions of the negative electrode sheet and the plurality of support portions of the separator can at least partially abut each other, so as to increase the gap and provide more space for the expansion of the negative electrode sheet.

[0022] In some embodiments, the side of the negative electrode sheet facing the positive electrode sheet is provided with a plurality of support portions, the side of the positive electrode sheet facing the positive electrode sheet is provided with a plurality of support portions, and the plurality of support portions of the negative electrode sheet facing the positive electrode sheet and the plurality of support portions of the positive electrode sheet facing the negative electrode sheet are at least partially arranged opposite to each other. By arranging the plurality of support portions of the negative electrode sheet and the plurality of support portions of the positive electrode sheet to face each other, the plurality of support portions of the negative electrode sheet and the plurality of support portions of the positive electrode sheet can support each other, so as to increase the gap and provide more space for the expansion of the negative electrode sheet.

[0023] In some embodiments, the separator is provided with a plurality of support portions on both sides. The gap includes a first gap formed between the positive electrode sheet and the separator and a second gap formed between the negative electrode sheet and the separator. By arranging a plurality of support portions on both sides of the separator, the gap can be increased, and more space can be provided for the expansion of the negative electrode sheet.

[0024] In some embodiments, the shell includes a side wall arranged around the electrode assembly, and the material of the side wall includes steel. The thickness of the side wall is 0.3 mm to 1.5 mm, which can be 0.3 mm to 1.2 mm. By arranging the gap, the expansion force exerted by the electrode assembly on the side wall can be reduced. Therefore, the steel side wall can have a thickness less than or equal to 1.5 mm, thereby improving the energy density of the cylindrical battery cell. The thickness of the steel side wall is greater than or equal to 0.3 mm, so as to reduce the risk of deformation and rupture of the side wall under the expansion force of the electrode assembly, thereby improving the reliability of the cylindrical battery cell.

[0025] In some embodiments, the negative electrode sheet includes a negative electrode current collector and a negative electrode film layer provided on at least one side of the negative electrode current collector and containing a negative electrode active material, the negative electrode active material including a silicon-based material. The mass content of silicon in the negative electrode film layer is 2% to 19%, or 6% to 13%. The introduction of the silicon-based material can increase the capacity of the negative electrode active material and improve the energy density of the cylindrical battery cell. The gap can provide space for the expansion of the negative electrode sheet, thereby reducing the influence of the silicon-based material on the expansion force. The embodiments of the present application limit the mass content of silicon in the negative electrode film layer to the above range, so as to balance the expansion and capacity of the negative electrode sheet to some extent, and take into account the cycle performance and energy density of the cylindrical battery cell.

[0026] In some embodiments, the capacity area density of the negative electrode sheet is greater than or equal to 3.2 mAh / cm 2 The embodiments of the present application can reduce the influence of the increase in the area density of the negative electrode sheet on the expansion force by providing the gap, thereby improving the capacity of the negative electrode sheet and the energy density of the cylindrical battery cell.

[0027] In some embodiments, the capacity area density of the negative electrode sheet is 3.3 mAh / cm 2 to 11.5 mAh / cm 2 The embodiments of the present application can balance the capacity and expansion of the negative electrode sheet to some extent, and take into account the energy density and cycle performance of the cylindrical battery cell.

[0028] In some embodiments, the capacity area density of the negative electrode sheet is 3.96 mAh / cm 2 to 7.56 mAh / cm 2 , which can further take into account the energy density and cycle performance of the cylindrical battery cell.

[0029] In some embodiments, the gap has a winding start end and a winding end. The radial dimension of the portion of the gap close to the winding start end is greater than or equal to the radial dimension of the portion of the gap close to the winding end. The portion of the gap close to the winding start end has a larger radial dimension to provide more expansion space for the negative electrode sheet in the middle of the electrode assembly, reduce the risk of the middle of the electrode assembly collapsing due to expansion, and improve the cycle performance of the cylindrical battery cell.

[0030] In some embodiments, the radial dimension of at least part of the gap gradually decreases along the winding direction. The radial dimension of the gap changes smoothly, reducing the sudden change in the radial dimension of the gap, reducing the stress concentration of the negative electrode sheet, and improving the cycle performance of the cylindrical battery cell.

[0031] In some embodiments, the gap includes a middle region and two end regions arranged along an axial direction of the cylindrical battery cell, the middle region is located between the two end regions, and a radial dimension of the middle region is smaller than a radial dimension of the end regions. The end regions have a larger radial dimension to facilitate electrolyte entering the gap, improve the wettability of the electrolyte to the electrode sheet, and improve the cycle performance of the cylindrical battery cell.

[0032] In some embodiments, the radial dimension of the gap gradually decreases in a direction from the end region to the middle region, to reduce the abrupt change of the radial dimension of the gap, reduce the stress concentration of the negative electrode sheet, and improve the cycle performance of the cylindrical battery cell.

[0033] In some embodiments, the spacer includes a base and a plurality of support portions, the support portions include organic particles arranged on the base. The organic particles can support the positive electrode sheet or the negative electrode sheet to increase the gap and provide space for the expansion of the negative electrode sheet.

[0034] In some embodiments, the base of the spacer includes a base film and an inorganic particle layer arranged on the base film, and the organic particles at least partially protrude from the inorganic particle layer.

[0035] The inorganic particle layer includes a plurality of inorganic particles, and gaps are formed between the inorganic particles and the organic particles, which are sufficient and unevenly distributed, to improve the air permeability of the spacer and improve the cycle performance and reliability of the cylindrical battery cell.

[0036] In some embodiments, one of the positive electrode sheet and the negative electrode sheet includes a first tab, and the other includes a second tab. The cylindrical battery cell includes a first electrode lead-out portion and a second electrode lead-out portion, the first electrode lead-out portion is electrically connected to the first tab, and the second electrode lead-out portion is electrically connected to the second tab. In the axial direction of the cylindrical battery cell, the first electrode lead-out portion and the second electrode lead-out portion are located on the same side of the electrode assembly. When a plurality of cylindrical battery cells are assembled into a group, the first electrode lead-out portions and the second electrode lead-out portions of the plurality of cylindrical battery cells can be arranged on the same side, to facilitate the connection of the current collecting member to the first electrode lead-out portions and the second electrode lead-out portions and simplify the battery structure.

[0037] In some embodiments, the housing includes a shell and an end cover, the shell includes an integrally formed side wall and an end wall, the side wall surrounds the electrode assembly, the end wall and the end cover are opposite in the axial direction of the cylindrical battery cell, and the end cover is sealingly connected to the side wall.

[0038] In some embodiments, one of the positive tab and the negative tab comprises a first tab, and the other comprises a second tab. The cylindrical battery cell further comprises an electrode terminal insulatedly arranged at the end wall, one of the first tab and the second tab is electrically connected to the electrode terminal, and the other is electrically connected to the end wall. The electrode terminal and the end wall can serve as two exposed electrodes of the cylindrical battery cell, and are located at the same side, which facilitates the assembly of a plurality of cylindrical battery cells into a group and simplifies the battery structure.

[0039] In some embodiments, the cylindrical battery cell further comprises a first current collecting member, which is located at a side of the first tab facing the end wall and connected to the first tab. The electrode terminal is abutted against and connected to a surface of the first current collecting member facing the end wall. The first current collecting member can serve as an adapter to realize the electrical connection between the first tab and the electrode terminal.

[0040] In some embodiments, the electrode terminal is provided with a terminal recess at a side facing the first current collecting member, and / or is provided with a terminal recess at a side away from the first current collecting member. A bottom wall of the terminal recess is welded to the first current collecting member. By providing the terminal recess, the thickness of the bottom wall of the terminal recess can be reduced, the power required for welding the electrode terminal and the first current collecting member from the outside can be reduced, the risk of particles generated by welding falling into the shell can be reduced, and the reliability of the cylindrical battery cell can be improved.

[0041] In some embodiments, the first tab and the second tab are both located at an end of the electrode assembly facing the end wall. The first tab and the second tab can share space in the axial direction, thereby improving the space utilization and increasing the energy density.

[0042] In some embodiments, the first tab is located at an end of the electrode assembly facing the end wall, and the second tab is located at an end of the electrode assembly facing the end cover. The cylindrical battery cell further comprises a second current collecting member connected to the second tab; the second current collecting member is connected to at least one of the end cover and the side wall.

[0043] In some embodiments, the height of the shell is 1.3 to 4 times the diameter of the shell. When the shell meets the above size requirements, the structural stability of the shell can be higher, and the use reliability of the cylindrical battery cell can be improved.

[0044] In some embodiments, the height of the shell is 50 mm to 150 mm.

[0045] In some embodiments, the diameter of the shell is 45 mm to 80 mm.

[0046] In a second aspect, the present application provides a battery comprising a plurality of cylindrical battery cells according to any one of the embodiments of the first aspect.

[0047] In a third aspect, the present application provides a power consuming device, which comprises the battery provided in any of the embodiments of the second aspect, and the battery is configured to provide power. BRIEF DESCRIPTION OF DRAWINGS

[0048] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the embodiments of the present application will be briefly introduced as follows. Obviously, the drawings described below are only some of the embodiments of the present application, and other drawings can also be obtained by those skilled in the art without any creative effort on the basis of the drawings.

[0049] FIG. 1 is a structural schematic diagram of a vehicle provided in some embodiments of the present application;

[0050] FIG. 2 is an exploded schematic diagram of a battery provided in some embodiments of the present application;

[0051] FIG. 3 is a structural schematic diagram of a battery module shown in FIG. 2;

[0052] FIG. 4 is a structural schematic diagram of a cylindrical battery cell in some embodiments of the present application;

[0053] FIG. 5 is an exploded schematic diagram of the cylindrical battery cell shown in FIG. 4;

[0054] FIG. 6 is a sectional view schematic diagram of an electrode assembly of the cylindrical battery cell provided in some embodiments of the present application;

[0055] FIG. 7 is an enlarged schematic diagram of a dashed line frame A in FIG. 6;

[0056] FIG. 8 is a schematic diagram of a separator of the electrode assembly of the cylindrical battery cell provided in some embodiments of the present application;

[0057] FIG. 9 is a partial sectional view schematic diagram of the electrode assembly of the cylindrical battery cell provided in some other embodiments of the present application;

[0058] FIG. 10 is a schematic diagram of the separator of the electrode assembly of the cylindrical battery cell provided in some other embodiments of the present application;

[0059] FIG. 11 is a partial sectional view schematic diagram of the electrode assembly of the cylindrical battery cell provided in some other embodiments of the present application;

[0060] FIG. 12 is a schematic diagram of a positive electrode sheet of the electrode assembly provided in some embodiments of the present application in a flattened state;

[0061] FIG. 13 is a sectional view schematic diagram of the positive electrode sheet of the electrode assembly provided in some embodiments of the present application;

[0062] FIG. 14 is a sectional view schematic diagram of a negative electrode sheet of the electrode assembly provided in some embodiments of the present application;

[0063] Fig. 15 is a cross-sectional view of a positive electrode sheet according to some embodiments of the present application;

[0064] Fig. 16 is a cross-sectional view of a negative electrode sheet according to some embodiments of the present application;

[0065] Fig. 17 is a partial cross-sectional view of an electrode assembly of a cylindrical battery cell according to some embodiments of the present application;

[0066] Fig. 18 is a partial cross-sectional view of an electrode assembly of a cylindrical battery cell according to some embodiments of the present application;

[0067] Fig. 19 is a cross-sectional view of the battery cell shown in Fig. 4;

[0068] Fig. 20 is an enlarged view of the circle in Fig. 19;

[0069] Fig. 21 is a partial cross-sectional view of a battery cell according to some embodiments of the present application.

[0070] In the drawings, the drawings are not drawn to scale.

[0071] The reference numerals are explained as follows: 1, vehicle; 2, battery; 3, controller; 4, motor; 5, case; 5a, first case portion; 5b, second case portion; 5c, accommodation space; 6, battery module; 7, cylindrical battery cell; 7a, first electrode lead-out portion; 7b, second electrode lead-out portion; 10, electrode assembly; 10a, first tab; 10b, second tab; 10c, electrode main body; 11, positive electrode sheet; 111, positive electrode base; 112, positive electrode protrusion; 113, positive electrode recess; 11a, positive electrode current collector; 11b, positive electrode film layer; 11c, positive electrode particle coating layer; 12, negative electrode sheet; 121, negative electrode base; 122, negative electrode protrusion; 123, negative electrode recess; 12a, negative electrode current collector; 12b, negative electrode film layer; 12c, negative electrode particle coating layer; 13, separator; 131, separator base; 13a, base film; 13b, coating layer; 14, support portion; 141, first support portion; 142, second support portion; 15, base; 151, first surface; 20, housing; 21, case; 211, end wall; 212, side wall; 22, end cover; 30, electrode terminal; 31, terminal recess; 32, through hole; 40, first current collecting member; 50, cover plate; 60, second current collecting member; G, gap; G1, first gap; G2, second gap; C1, middle region; C2, end region; C3, transition region; E1, winding start end; E2, winding end end; E3, positive electrode winding start end; E4, positive electrode winding end end; E5, negative electrode winding start end; E6, negative electrode winding end end; E7, first end; E8, second end; P, organic particle; P1, first organic particle; P2, second organic particle; P3, inorganic particle layer; V, winding direction; Z, axial direction. DETAILED DESCRIPTION

[0072] In order to make the objects, technical solutions, and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0073] 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 in the specification herein is for describing particular embodiments only and is not intended to be limiting of the application. Unless otherwise defined, all terms used in disclosing the application, including technical and scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description of the application herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The articles "a", "an", and "the" as used herein are to be construed to mean "at least one" or "one or more", unless otherwise indicated. The terms "comprise", "comprising", "comprises", "include", "including", and "includes" as used herein are to be construed as optionally permitting the presence of one or more elements, so long as the presence of the one or more elements does not change the basic function of the device or method to which the term refers. The terms "first", "second", "third", etc. as used herein are to be construed as describing different objects, and not to be construed as describing a particular order or sequence unless otherwise indicated.

[0074] 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 appearances of the phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are they necessarily mutually exclusive of one another.

[0075] In the description of the application, it is necessary to explain that, unless otherwise explicitly specified and limited, the terms "mount", "connect", "connection", "attach" should be understood in a broad sense, for example, it can be fixed connection, or detachable connection, or integrally connected; it can be directly connected, or indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in the application can be understood according to the specific circumstances.

[0076] The term "and / or" in the application is only to describe the association relationship of the associated objects, which means that there can be three kinds of relationships, for example, A and / or B can mean that A exists alone, A and B exist together, and B exists alone. In addition, the character " / " in the application generally represents that the front and rear associated objects have an "or" relationship.

[0077] In the embodiments of the application, the same reference signs represent the same components, and for the sake of brevity, the detailed description of the same components is omitted in different embodiments. It should be understood that the thickness, length, width and other dimensions of various components in the embodiments of the application shown in the drawings, as well as the overall thickness, length, width and other dimensions of the integrated device, are only exemplary and should not constitute any limitation on the application.

[0078] "Multiple" appearing in the application means more than two (including two).

[0079] The cylindrical battery cell can be a cylindrical secondary battery, which refers to a battery cell that can be activated by charging after discharging to continue to be used.

[0080] The battery can refer to a single physical module including one or more cylindrical battery cells to provide higher voltage and capacity.

[0081] The cylindrical battery cell generally includes an electrode assembly and a case for accommodating the electrode assembly. The electrode assembly generally includes a positive electrode sheet, a negative electrode sheet, and a separator separating the positive electrode sheet and the negative electrode sheet.

[0082] During the cyclic charging and discharging of the cylindrical battery cell, the negative electrode sheet expands due to the intercalation of ions; as the diameter of the cylindrical battery cell increases, the amount of expansion of the negative electrode sheet accumulates and can generate a greater expansion force, which can cause the pressure between the positive electrode sheet and the negative electrode sheet to increase, resulting in the electrolyte in the internal pores of the positive electrode film layer of the positive electrode sheet and the electrolyte in the internal pores of the negative electrode film layer of the negative electrode sheet being squeezed out, affecting the cycle performance of the cylindrical battery cell.

[0083] In addition, the expanded electrode assembly can also squeeze the case, causing the risk of deformation or even rupture of the case, affecting the use reliability of the cylindrical battery cell.

[0084] In view of this, the embodiments of the present application provide a technical solution, which provides a space for the expansion of the negative electrode sheet by arranging a gap between the positive electrode sheet and the negative electrode sheet, thereby reducing the expansion force, improving the cycle performance of the cylindrical battery cell with a larger diameter, and improving the reliability of the cylindrical battery cell.

[0085] The cylindrical battery cell described in the embodiments of the present application is suitable for a battery and a power consumption device using the battery.

[0086] The power consumption device can be a device using a battery as a power source or a variety of energy storage systems using a battery 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 car, 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 car toy, an electric ship toy, and an electric plane toy, etc., and the spacecraft can include an airplane, a rocket, a space shuttle, a spacecraft, etc.

[0087] The following embodiments are described by taking a vehicle as an example for convenience of description.

[0088] FIG. 1 is a structural schematic diagram of a vehicle provided by some embodiments of the present application.

[0089] As shown in FIG. 1, the vehicle 1 is internally provided with a battery 2, which can be arranged at the bottom, head or tail of the vehicle 1. The battery 2 can be used for power supply of the vehicle 1, for example, the battery 2 can be used as an operating power source of the vehicle 1.

[0090] The vehicle 1 can further comprise a controller 3 and a motor 4, the controller 3 being configured to control the battery 2 to supply power to the motor 4, for example, for the power requirements of the vehicle 1 during start-up, navigation and travel.

[0091] In some embodiments of the present application, the battery 2 can not only serve as a power source for the operation of the vehicle 1, but also serve as a driving power source for the vehicle 1, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1.

[0092] FIG. 2 is an exploded view of a battery according to some embodiments of the present application. As shown in FIG. 2, the battery 2 comprises a box 5 and a cylindrical battery cell (not shown in FIG. 2), the cylindrical battery cell being accommodated in the box 5.

[0093] The box 5 is configured to accommodate the cylindrical battery cell, and the box 5 can have various structures. In some embodiments, the box 5 can comprise a first box part 5a and a second box part 5b, the first box part 5a and the second box part 5b being coupled to each other, and the first box part 5a and the second box part 5b together defining an accommodation space 5c for accommodating the cylindrical battery cell. The second box part 5b can be a hollow structure with one open end, and the first box part 5a can be a plate-like structure, the first box part 5a being coupled to the open end of the second box part 5b to form the box 5 with the accommodation space 5c. Alternatively, the first box part 5a and the second box part 5b can both be hollow structures with one open end, the open end of the first box part 5a being coupled to the open end of the second box part 5b to form the box 5 with the accommodation space 5c. Of course, the first box part 5a and the second box part 5b can have various shapes, such as a cylinder, a cuboid, etc.

[0094] To improve the sealing performance of the first box part 5a and the second box part 5b after being coupled, a sealing member, such as a sealing glue, a sealing ring, etc., can be provided between the first box part 5a and the second box part 5b.

[0095] Suppose the first box part 5a is coupled to the top of the second box part 5b, the first box part 5a can also be referred to as an upper box cover, and the second box part 5b can also be referred to as a lower box.

[0096] In the battery 2, the cylindrical battery cell can be one or multiple. If the cylindrical battery cell is multiple, the multiple cylindrical battery cells can be connected in series, in parallel or in a mixed manner. The mixed manner means that the multiple cylindrical battery cells are connected in both series and parallel. The multiple cylindrical battery cells can be directly connected in series, in parallel or in a mixed manner, and then the whole of the multiple cylindrical battery cells is accommodated in the box 5. Alternatively, the multiple cylindrical battery cells can be first connected in series, in parallel or in a mixed manner to form a battery module 6, and then the multiple battery modules 6 are connected in series, in parallel or in a mixed manner to form a whole, which is accommodated in the box 5.

[0097] The cylindrical battery cell can be the smallest unit of the battery.

[0098] In some embodiments, the box 5 can be part of the chassis structure of the vehicle. For example, part of the box 5 can be at least part of the floor of the vehicle, or part of the box 5 can be at least part of the cross beam and the longitudinal beam of the vehicle.

[0099] In some embodiments, the battery 2 can be an energy storage device. The energy storage device includes an energy storage container, an energy storage cabinet, etc.

[0100] FIG. 3 is a structural schematic diagram of the battery module shown in FIG. 2.

[0101] In some embodiments, as shown in FIG. 3, the plurality of cylindrical battery cells 7 are connected in series or in parallel or in a hybrid manner to form a battery module 6. The plurality of battery modules 6 are connected in series or in parallel or in a hybrid manner to form a whole and are accommodated in the box.

[0102] The plurality of cylindrical battery cells 7 in the battery module 6 can be electrically connected through a busbar component to realize parallel connection, series connection or hybrid connection of the plurality of cylindrical battery cells 7 in the battery module 6. The busbar component can be one or more, and each busbar component is used to electrically connect at least two cylindrical battery cells 7.

[0103] The cylindrical battery cell 7 can be a lithium ion battery cell, a sodium ion battery cell, a sodium lithium ion battery cell, a lithium metal battery cell, a sodium metal battery cell, a lithium sulfur battery cell, a magnesium ion battery cell, a nickel hydrogen battery cell, a nickel cadmium battery cell, a lead-acid battery cell, etc.

[0104] FIG. 4 is a structural schematic diagram of a cylindrical battery cell in some embodiments of the present application; FIG. 5 is an exploded schematic diagram of the cylindrical battery cell shown in FIG. 4; FIG. 6 is a cross-sectional schematic diagram of an electrode assembly of the cylindrical battery cell provided in some embodiments of the present application; FIG. 7 is an enlarged schematic diagram of the dashed box A in FIG. 6; and FIG. 8 is a schematic diagram of a separator of the electrode assembly of the cylindrical battery cell provided in some embodiments of the present application.

[0105] Referring to FIGS. 4 to 8, the embodiments of the present application provide a cylindrical battery cell 7, which includes a shell 20 and an electrode assembly 10, at least part of the electrode assembly 10 being accommodated in the shell 20.

[0106] The shell 20 is a hollow structure, and an accommodation space for accommodating the electrode assembly 10 and the electrolyte is formed inside the shell 20. The shell 20 of the cylindrical battery cell 7 is a cylindrical shell.

[0107] As an example, the shell 20 includes a shell body 21 having an opening and an end cap 22 for covering the opening.

[0108] The shell 21 is a component for fitting the end cap 22 to form an internal cavity of the cylindrical battery cell 7, and the formed internal cavity can be used to accommodate the electrode assembly 10, electrolyte, and other components.

[0109] The shell 21 and the end cap 22 can be independent components. For example, an opening can be provided on the shell 21, and the end cap 22 can be fitted to cover the opening to form the internal cavity of the cylindrical battery cell 7.

[0110] The shell 21 can be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, etc.

[0111] The end cap 22 can have a shape that is adapted to the shape of the shell 21 to fit the shell 21. The material of the end cap 22 can be the same as or different from the material of the shell 21. Optionally, the end cap 22 can be made of a material (such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc.) that has a certain hardness and strength, so that the end cap 22 is less likely to deform when subjected to extrusion and impact, and the cylindrical battery cell 7 can have higher structural strength and improved reliability.

[0112] The end cap 22 can be connected to the shell 21 by welding, bonding, clamping, or other means.

[0113] The shell 21 can be open at one end or both ends. In some examples, the shell 21 can have a structure that is open at one side, and the end cap 22 is provided as one and covers the shell 21. In other examples, the shell 21 can also have a structure that is open at both ends, and the end cap 22 is provided as two and covers the two openings of the shell 21.

[0114] In some embodiments, the shell 21 includes an integrally formed side wall 212 and an end wall 211, the end wall 211 and the end cap 22 are opposite along the axial direction Z of the cylindrical battery cell, and the end cap 22 is sealingly connected to the side wall 212.

[0115] The electrode assembly 10 is a component that undergoes an electrochemical reaction in the cylindrical battery cell 7. The electrode assembly 10 can be entirely accommodated in the housing 20 or partially accommodated in the housing 20. For example, a portion of the tab of the electrode assembly 10 can extend outside the housing 20.

[0116] Optionally, the electrode assembly 10 is entirely accommodated in the housing 20.

[0117] In some embodiments, the diameter of the cylindrical battery cell is greater than or equal to 40 mm. The large-diameter cylindrical battery cell has a higher capacity, which is beneficial to improving the energy density when multiple cylindrical battery cells are assembled into a group.

[0118] In some embodiments, the electrode assembly 10 includes a positive electrode tab 11 and a negative electrode tab 12. During charging and discharging of the cylindrical battery cell 7, active ions (e.g., lithium ions) are intercalated and deintercalated between the positive electrode tab 11 and the negative electrode tab 12.

[0119] In some embodiments, the positive electrode tab 11 can include a positive electrode current collector and a positive electrode film layer disposed on at least one surface of the positive electrode current collector.

[0120] As an example, the positive electrode current collector has two surfaces opposite in the thickness direction thereof, and the positive electrode film layer is disposed on either one or both of the two opposite surfaces of the positive electrode current collector.

[0121] As an example, the positive electrode current collector can employ a metal foil or a composite current collector. For example, as the metal foil, silver surface-treated aluminum or stainless steel, stainless steel, copper, aluminum, nickel, a carbon electrode, carbon, nickel, or titanium, or the like can be employed. The composite current collector can include a polymer material base layer and a metal layer. The composite current collector can be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, or the like) on a polymer material base material (e.g., a base material of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, or the like).

[0122] As an example, the positive electrode film layer includes a positive electrode active material, which can include at least one of lithium-containing phosphates, lithium transition metal oxides, and respective modified compounds thereof. However, the present application is not limited to these materials, and other conventional materials that can be used as battery positive electrode active materials can also be used. These positive electrode active materials can be used alone or in combination with two or more. Among them, examples of the lithium-containing phosphates can include, but are not limited to, at least one of lithium iron phosphate (e.g., LiFePO4 (which can also be referred to as LFP)), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate (e.g., LiMnPO4), a composite material of lithium manganese phosphate and carbon, lithium manganese iron phosphate, and a composite material of lithium manganese iron phosphate and carbon. Examples of the lithium transition metal oxides can include, but are not limited to, at least one of lithium cobalt oxide (e.g., LiCoO2), lithium nickel oxide (e.g., LiNiO2), lithium manganese oxide (e.g., LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (e.g., LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (which can also be referred to as NCM 333 ), LiNi 0.5 Co 0.2 Mn 0.3 O2 (which can also be referred to as NCM 523 ), LiNi 0.5 Co 0.25 Mn0.25 O2(also can be referred to as NCM 211 ), LiNi 0.6 Co 0.2 Mn 0.2 O2(also can be referred to as NCM 622 ), LiNi 0.8 Co 0.1 Mn 0.1 O2(also can be referred to as NCM 811 ), lithium nickel cobalt aluminum oxide (such as LiNi 0.80 Co 0.15 Al 0.05 O2), and modified compounds thereof.

[0123] In some embodiments, the negative electrode sheet 12 can include a negative electrode current collector and a negative electrode film layer disposed on at least one surface of the negative electrode current collector.

[0124] As an example, the negative electrode current collector can employ a metal foil, a foamed metal, a foamed carbon, or a composite current collector. For example, as the metal foil, silver surface-treated aluminum or stainless steel, stainless steel, copper, aluminum, nickel, a carbon electrode, a carbon, nickel, or titanium, or the like can be employed. The foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloy, or the like. The composite current collector can include a high molecular material base layer and a metal layer. The composite current collector can be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, or the like) on a high molecular material base material (such as a base material of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, or the like).

[0125] As an example, the negative electrode current collector has two surfaces opposite in the thickness direction thereof, and the negative electrode film layer is disposed on either one or both of the two opposite surfaces of the negative electrode current collector.

[0126] As an example, the negative electrode film layer includes a negative electrode active material. For example, the negative electrode active material can include at least one of artificial graphite, natural graphite, soft carbon, hard carbon, a silicon-based material, a tin-based material, lithium titanate, and the like. The silicon-based material can be selected from at least one of elemental silicon, a silicon oxide compound, a silicon-carbon composite, a silicon-nitrogen composite, and a silicon alloy. The tin-based material can be selected from at least one of elemental tin, a tin oxide compound, and a tin alloy. However, the present application is not limited to these materials, and other conventional materials that can be used as a battery negative electrode active material can also be used. These negative electrode active materials can be used alone or in combination of two or more.

[0127] In some embodiments, the material of the positive electrode current collector can be aluminum, and the material of the negative electrode current collector can be copper.

[0128] In some embodiments, the electrode assembly 10 further includes a separator 13 disposed between the positive electrode sheet 11 and the negative electrode sheet 12. The separator 13 can function to prevent short-circuiting between the positive and negative electrodes while allowing active ions to pass through.

[0129] In some embodiments, the cylindrical battery cell 7 further includes an electrolyte that functions to conduct ions between the positive electrode sheet 11 and the negative electrode sheet 12. The electrolyte can be in a liquid state, a gel state, or a solid state.

[0130] In some embodiments, the liquid electrolyte includes an electrolyte salt and a solvent.

[0131] As an example, the electrolyte salt can be selected from at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bisfluorosulfonylimide, lithium bis-trifluoromethanesulfonylimide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluoro oxalato borate, lithium difluoro dioxalato borate, lithium difluoro dioxalato phosphate, and lithium tetrafluoro oxalato phosphate.

[0132] As an example, the solvent can be selected from at least one of ethylene carbonate, propylene carbonate, methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, butyl sulfone, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone. The solvent can also be selected from an ether-based solvent. The ether-based solvent can include one or more of ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyl tetrahydrofuran, diphenyl ether, and a crown ether.

[0133] In some embodiments, the gel-state electrolyte includes a polymer as a backbone network of the electrolyte, in combination with an ionic liquid-lithium salt.

[0134] In some embodiments, the solid-state electrolyte includes a polymer solid-state electrolyte, an inorganic solid-state electrolyte, a composite solid-state electrolyte.

[0135] As an example, the polymer solid-state electrolyte can be a polyether (polyethylene oxide), a polysiloxane, a polycarbonate, a polyacrylonitrile, a polyvinylidene fluoride, a polymethyl methacrylate, a single-ion polymer, a polyionic liquid-lithium salt, cellulose, or the like.

[0136] As an example, the inorganic solid-state electrolyte can be one or more of an oxide solid-state electrolyte (crystalline perovskite, sodium superionic conductor, garnet, amorphous LiPON thin film), a sulfide solid-state electrolyte (crystalline lithium superionic conductor (lithium germanium phosphorous sulfide, argyrodite), amorphous sulfide), and a halide solid-state electrolyte, a nitride solid-state electrolyte, and a hydride solid-state electrolyte.

[0137] As an example, the composite solid-state electrolyte is formed by adding an inorganic solid-state electrolyte filler to a polymer solid-state electrolyte.

[0138] In some embodiments, the positive electrode sheet 11, the negative electrode sheet 12, and the separator 13 are wound.

[0139] The electrode assembly 10 is a wound structure. As an example, the positive electrode sheet 11, the separator 13, and the negative electrode sheet 12 are wound into a cylindrical wound structure.

[0140] In some embodiments, the diameter of the cylindrical battery cell 7 is greater than or equal to 40 mm. The cylindrical battery cell 7 includes the electrode assembly 10 and a housing 20. At least a portion of the electrode assembly 10 is housed in the housing 20.

[0141] The electrode assembly 10 includes the positive electrode sheet 11, the negative electrode sheet 12, and the separator 13, which are wound, and the separator 13 separates the positive electrode sheet 11 and the negative electrode sheet 12.

[0142] The negative electrode active material of the negative electrode sheet 12 includes at least one of a silicon-based material and a carbon-based material.

[0143] A gap G is formed between the positive electrode sheet 11 and the negative electrode sheet 12, the gap G extends in a winding direction V of the electrode assembly 10, and a radial dimension of at least a portion of the gap G is 5 μm to 60 μm.

[0144] As an example, the radial dimension of the gap G can be a dimension of the gap G in a radial direction of the cylindrical battery cell. The radial dimension W of the gap G can be the same or different at different positions.

[0145] Optionally, the radial dimension W of each portion of the gap G is 5 μm to 60 μm.

[0146] As an example, the carbon-based material includes at least one of artificial graphite and natural graphite.

[0147] As an example, the silicon-based material includes at least one of elemental silicon, a silicon oxide compound, a silicon-carbon composite, a silicon-nitrogen composite, and a silicon alloy.

[0148] As an example, the gap G can be a space between the positive electrode sheet 11 and the negative electrode sheet 12 that is not filled with the separator 13.

[0149] As an example, the gap G is wound in the winding direction V as multiple turns.

[0150] As an example, the radial dimension W of the gap G can be 5 μm, 6 μm, 8 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 53 μm, 55 μm, 58 μm, 60 μm, or a range defined by any two of the above values.

[0151] As an example, the radial dimension of the gap G can be measured in the following manner:

[0152] Discharge the cylindrical battery cell to a lower cut-off voltage (e.g., 2.5 V);

[0153] Use CT (Computed Tomography) technology to obtain an image of a cross-section of the electrode assembly using X-rays, the cross-section being perpendicular to the axial direction of the cylindrical battery cell;

[0154] Based on the image, measure the distance D1 between the outer surface of the 6th positive electrode sheet and the inner surface of the 10th positive electrode sheet in the radial direction of the electrode assembly;

[0155] Disassemble the cylindrical battery cell and measure the thickness t1 of the positive electrode sheet, the thickness t2 of the negative electrode sheet, and the thickness t3 of the separator.

[0156] There are 3 layers of positive electrode sheets, 4 layers of negative electrode sheets, and 8 layers of separators between the outer surface of the 6th positive electrode sheet and the inner surface of the 10th positive electrode sheet. Eight layers of gaps are formed between the outer surface of the 6th positive electrode sheet and the inner surface of the 10th positive electrode sheet. W = (D1-3xt1-4xt2-8xt3) / 8.

[0157] During the cycling of the cylindrical battery cell 7, the gap G can provide space for the expansion of the negative electrode sheet 12. In the present application, the radial dimension W of at least part of the gap G is limited to be greater than or equal to 5 μm, which can reduce the compression of the electrolyte in the internal pores of the positive electrode film layer of the positive electrode sheet 11 and the negative electrode film layer of the negative electrode sheet 12, can reduce the concentration difference of the electrolyte in different regions inside the electrode sheet, and can improve the cycling performance of the cylindrical battery cell 7 with a larger diameter. The gap G can reduce the expansion amount of the electrode assembly 10, thereby reducing the compression of the shell 20, reducing the risk of deformation and cracking of the shell 20, and improving the reliability of the cylindrical battery cell 7. In the present application, the radial dimension W of at least part of the gap G is limited to be less than or equal to 60 μm, so as to shorten the ion migration path between the positive electrode sheet and the negative electrode sheet, reduce the internal resistance of the cylindrical battery cell 7, reduce heat generation, and reduce the impact of the gap G on the energy density.

[0158] The gap G can also accommodate electrolyte, so as to improve the electrolyte infiltration effect on the positive and negative electrode sheets and improve the cycle performance of the cylindrical battery cell.

[0159] In addition, when the negative electrode sheet 12 has ion precipitation problems during the cycle process, such as lithium precipitation, the gap G can provide space for the deformation of the separator 13, so that the separator 13 can release the pressure exerted by the lithium dendrites through deformation, thereby avoiding the separator 13 being pierced to a certain extent, reducing the risk of short circuit, and improving the reliability.

[0160] In some embodiments, the radial dimension of the gap G is 10-50 μm.

[0161] In some embodiments, the negative active material includes a carbon-based material. The carbon-based material has high cycle stability, which can improve the cycle performance of the cylindrical battery cell.

[0162] In some embodiments, at least one of the positive electrode sheet 11, the negative electrode sheet 12, and the separator 13 includes a base 15 and a plurality of support portions 14 provided on the base 15. The base 15 has two first surfaces 151 oppositely arranged along the thickness direction thereof, and the plurality of support portions 14 are protruded from at least one of the first surfaces 151 to form the gap G between the positive electrode sheet 11 and the negative electrode sheet 12.

[0163] As an example, the plurality of support portions 14 are dispersedly arranged on the first surface 151.

[0164] In some examples, one of the first surfaces 151 of the base 15 is provided with the plurality of support portions 14, of course, the first surface 151 of the base 15 can be inwardly radially provided with the plurality of support portions 14, or the first surface 151 of the base 15 can be outwardly radially provided with the plurality of support portions 14. In other examples, both of the first surfaces 151 of the base 15 are provided with the plurality of support portions 14.

[0165] In some examples, the positive electrode sheet 11 includes a base and a support portion, and for the convenience of description, the base of the positive electrode sheet 11 can be referred to as a positive electrode base. For the example that the positive electrode sheet is provided with the support portion, D1 is measured on the outer surface of the positive electrode base of the 6th layer positive electrode sheet and the inner surface of the positive electrode base of the 10th layer positive electrode sheet, and the thickness t1 is measured on the positive electrode base.

[0166] Optionally, the negative electrode sheet 12 and the separator 13 can be provided with the support portion, or can not be provided with the support portion. In the plurality of support portions of the positive electrode sheet 11, some of the support portions can be in contact with the separator, or all of the support portions can be in contact with the separator.

[0167] In some examples, the negative tab 12 includes a base and a support portion, and the base of the negative tab 12 can be referred to as a negative base for ease of description. For examples in which the negative tab 12 has a support portion, the thickness t2 is measured at the negative base.

[0168] Optionally, the positive tab 11 and the separator 13 can be provided with a support portion, or can not be provided with a support portion. In the plurality of support portions of the negative tab 12, some of the support portions can be in contact with the separator, or all of the support portions can be in contact with the separator.

[0169] In some examples, the separator 13 includes a base 15 and a support portion 14, and the base of the separator 13 can be referred to as a separator base 131 for ease of description. For examples in which the separator 13 has a support portion, the thickness t3 is measured at the separator base 131.

[0170] Optionally, the positive tab 11 and the negative tab 12 can be provided with a support portion, or can not be provided with a support portion. As an example, the positive tab 11 can be in contact with some of the support portions of the separator 13, and / or the negative tab 12 can be in contact with some of the support portions of the separator 13.

[0171] In some examples, at least two of the positive tab 11, the negative tab 12, and the separator 13 are provided with a support portion 14, and the support portions 14 of the two can be formed in the same way or in different ways.

[0172] In some examples, the support portion 14 can be rigid or flexible.

[0173] By providing the plurality of protruding support portions 14, the gap G between the positive tab 11 and the negative tab 12 can be increased, more space for expansion of the negative tab 12 can be provided, and the cycle performance of the cylindrical battery cell 7 can be improved.

[0174] In some embodiments, the support portion 14 is configured to be compressible. During the cycle of the cylindrical battery cell 7, the support portion 14 can be compressed when under pressure, thereby providing more space for expansion of the negative tab 12. The compressible support portion 14 can release stress by deforming under compression, thereby reducing the risk of the positive tab 11 or the negative tab 12 being damaged by the support portion 14 and improving reliability.

[0175] In some embodiments, the plurality of support portions 14 includes a first support portion 141 and a second support portion 142, and the height H1 at which the first support portion 141 protrudes from the first surface 151 is greater than the height H2 at which the second support portion 142 protrudes from the first surface 151.

[0176] There can be one or more first support portions 141. There can be one or more second support portions 142. Optionally, there are a plurality of first support portions 141 and a plurality of second support portions 142.

[0177] The first support portion 141 has a large height, which can support the positive electrode sheet 11 or the negative electrode sheet 12 to form a large gap G, thereby providing more space for the expansion of the negative electrode sheet 12. The second support portion 142 has a small height and occupies a small space. As the negative electrode sheet 12 expands, the gap G gradually decreases; the second support portion 142 can be pressed only after the negative electrode sheet 12 expands to a certain extent, thereby reducing the pressure on the negative electrode sheet 12 in the initial stage of expansion. When the second support portion 142 is pressed, the second support portion 142 can slow down the expansion of the negative electrode sheet 12 to some extent, reduce the electrolyte squeezed out by the negative electrode sheet 12, and improve the cycle performance of the cylindrical battery cell 7.

[0178] In some embodiments, the first support portion 141 is provided in a plurality, and the second support portion 142 is provided in a plurality.

[0179] In some embodiments, the height of the first support portion 141 is 1.1 to 15 times, optionally 2 to 7 times, the height of the second support portion 142.

[0180] In some embodiments, the separator 13 comprises a plurality of support portions 14 and a separator base portion 131. Optionally, the plurality of support portions 14 of the separator 13 comprises the first support portion 141 and the second support portion 142.

[0181] In some embodiments, at least one of the positive electrode sheet 11, the negative electrode sheet 12, and the separator 13 comprises the organic particle P, and the support portion 14 comprises the organic particle P.

[0182] For example, in the electrode assembly 10, one of the positive electrode sheet 11, the negative electrode sheet 12, and the separator 13 can be provided with the organic particle P, both of them can be provided with the organic particle P 4, or all of them can be provided with the organic particle P.

[0183] The organic particle P can play a supporting role to form the gap G. When the cylindrical battery cell 7 experiences thermal runaway, the organic particle P can form a gel film structure at high temperature, thereby reducing the diffusion channel of active ions and delaying the time of thermal spread, thereby improving the reliability of the cylindrical battery cell 7.

[0184] For example, the organic particle P can be formed on the positive electrode sheet 11, the negative electrode sheet 12, or the separator 13 by coating. The support portion 14 formed by coating the organic particle P can simplify the forming process.

[0185] In some embodiments, the plurality of organic particles P comprises a first organic particle P1 and a second organic particle P2, and the number average particle size of the first organic particle P1 is greater than the number average particle size of the second organic particle P2.

[0186] It should be noted that the number average path of the organic particles is the arithmetic mean of the particle size of the organic particles counted by the number of the organic particles. The particle size of the organic particles can refer to the distance between the two most distant points on the organic particles.

[0187] The first organic particles P1 with a larger number average particle size can support the positive electrode sheet 11 or the negative electrode sheet 12 to form a larger gap G, thereby providing more space for the expansion of the negative electrode sheet 12. The second organic particles P2 with a smaller number average particle size can be compressed after the negative electrode sheet 12 expands to a certain extent, which can reduce the pressure on the negative electrode sheet 12 in the initial stage of expansion. When the second organic particles P2 are compressed, the second organic particles P2 can slow down the expansion of the negative electrode sheet 12 to some extent, reduce the electrolyte squeezed out by the negative electrode sheet 12, and improve the cycle performance of the cylindrical battery cell 7.

[0188] In some embodiments, the plurality of support portions 14 includes a first support portion 141 and a second support portion 142, the height of the first support portion 141 protruding from the first surface is greater than the height of the second support portion 142 protruding from the first surface. The plurality of organic particles P includes first organic particles P1 and second organic particles P2. The first support portion 141 includes the first organic particles P1, and the second support portion 142 includes the second organic particles P2.

[0189] By setting the first organic particles P1 and the second organic particles P2 with different number average particle sizes, the first support portion 141 and the second support portion 142 with different heights can be formed. The first support portion 141 has a larger height, which can support the positive electrode sheet 11 or the negative electrode sheet 12 to form a larger gap G, thereby providing more space for the expansion of the negative electrode sheet 12. The second support portion 142 can be compressed after the negative electrode sheet 12 expands to a certain extent, which can reduce the pressure on the negative electrode sheet 12 in the initial stage of expansion. When the second support portion 142 is compressed, the second support portion 142 can slow down the expansion of the negative electrode sheet 12 to some extent, reduce the electrolyte squeezed out by the negative electrode sheet 12, and improve the cycle performance of the cylindrical battery cell 7.

[0190] In some embodiments, the number average particle size of the first organic particles P1 is >10 μm, and the number average particle size of the second organic particles P2 is 2 μm-10 μm.

[0191] In some embodiments, the number average particle size of the first organic particles P1 is 12 μm-25 μm. For example, the number average particle size of the first organic particles P1 can be 12 μm, 13 μm, 15 μm, 16 μm, 18 μm, 20 μm, 21 μm, 22 μm, 24 μm, or 25 μm.

[0192] In some embodiments, the second organic particles P2 have a number average particle diameter of 2 μm to 9 μm. For example, the first organic particles P1 can have a number average particle diameter of 2 μm, 2.5 μm, 3 μm, 4 μm, 5 μm, 5.5 μm, 6 μm, 7 μm, 8 μm, or 9 μm.

[0193] In some embodiments, the ratio of the number average particle diameter of the first organic particles P1 to the number average particle diameter of the second organic particles P2 is greater than or equal to 1.5.

[0194] In some embodiments, the first organic particles P1 are secondary particles.

[0195] In some embodiments, the second organic particles P2 are primary particles.

[0196] It should be noted that primary particles and secondary particles have meanings well known in the art. Primary particles refer to particles that have not formed an agglomerated state. Secondary particles refer to agglomerated particles formed by the aggregation of two or more primary particles.

[0197] In some embodiments, the plurality of organic particles P includes the first organic particles P1, and the first organic particles P1 include one or more of a homopolymer or copolymer of a fluorine-containing alkenyl monomer unit, a homopolymer or copolymer of an alkenyl monomer unit, a homopolymer or copolymer of an unsaturated nitrile monomer unit, a homopolymer or copolymer of an alkylene oxide monomer unit, and a modified compound of each of the above homopolymers or copolymers.

[0198] In some embodiments, the fluorine-containing alkenyl monomer unit can be selected from one or more of difluoroethylene, vinylidene fluoride, trifluoroethylene, chlorotrifluoroethylene, tetrafluoroethylene, hexafluoropropylene.

[0199] In some embodiments, the alkenyl monomer unit can be selected from one or more of ethylene, propylene, butadiene, isoprene, and the like.

[0200] In some embodiments, the unsaturated nitrile monomer unit can be selected from one or more of acrylonitrile, methacrylonitrile, and the like.

[0201] In some embodiments, the alkylene oxide monomer unit can be selected from one or more of ethylene oxide, propylene oxide, and the like.

[0202] In some embodiments, the first organic particles P1 include one or more of polytetrafluoroethylene, polychlorotrifluoroethylene, polyfluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, polyacrylonitrile, polyethylene oxide, a copolymer of different fluorine-containing alkenyl monomer units, a copolymer of a fluorine-containing alkenyl monomer unit and an alkenyl monomer unit, a copolymer of a fluorine-containing alkenyl monomer unit and an acrylic monomer unit, a copolymer of a fluorine-containing alkenyl monomer unit and an acrylate monomer unit, and a modified compound of each of the above homopolymers or copolymers.

[0203] In some embodiments, the first organic particles P1 can include one or more of a vinylidene fluoride-trifluoroethylene copolymer, a vinylidene fluoride-hexafluoropropylene copolymer, a vinylidene fluoride-trifluoroethylene-hexafluoropropylene copolymer, a vinylidene fluoride-hexafluoropropylene-acrylic acid copolymer, a vinylidene fluoride-hexafluoropropylene-acrylate copolymer, and a modified compound of the above copolymers.

[0204] In some embodiments, the plurality of organic particles P includes second organic particles P2 including one or more of a homopolymer or a copolymer of an acrylate monomer unit, a homopolymer or a copolymer of an acrylic monomer unit, a homopolymer or a copolymer of a styrene monomer unit, a polyurethane compound, a rubber compound, and a modified compound of each of the above homopolymers or copolymers.

[0205] In some embodiments, the second organic particles P2 include one or more of a copolymer of an acrylate monomer unit and a styrene monomer unit, a copolymer of an acrylic monomer unit and a styrene monomer unit, a copolymer of an acrylic monomer unit-acrylate monomer unit-styrene monomer unit, a copolymer of a styrene monomer unit and an unsaturated nitrile monomer unit, a copolymer of a styrene monomer unit-olefin-based monomer unit-unsaturated nitrile monomer unit, and a modified compound of the above copolymers.

[0206] In some embodiments, the acrylate monomer unit can be selected from one or more of methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, methyl methacrylate, butyl methacrylate, isooctyl methacrylate, and the like.

[0207] In some embodiments, the acrylic monomer unit can be selected from one or more of acrylic acid, methacrylic acid, and the like.

[0208] In some embodiments, the styrene monomer unit can be selected from one or more of styrene, methylstyrene, and the like.

[0209] In some embodiments, the unsaturated nitrile monomer unit can be selected from one or more of acrylonitrile, methacrylonitrile, and the like.

[0210] In some embodiments, the second organic particles P2 can include one or more of butyl acrylate-styrene copolymer, butyl methacrylate-isooctyl methacrylate copolymer, isooctyl methacrylate-styrene copolymer, methacrylate-methacrylic acid-styrene copolymer, methyl acrylate-isooctyl methacrylate-styrene copolymer, butyl acrylate-isooctyl acrylate-styrene copolymer, butyl acrylate-isooctyl methacrylate-styrene copolymer, butyl methacrylate-isooctyl acrylate-styrene copolymer, butyl methacrylate-isooctyl methacrylate-styrene copolymer, styrene-acrylonitrile copolymer, styrene-butadiene-acrylonitrile copolymer, methyl acrylate-styrene-acrylonitrile copolymer, isooctyl methacrylate-styrene-acrylonitrile copolymer, styrene-vinyl acetate copolymer, styrene-vinyl acetate-pyrrolidone copolymer, and modified compounds of the above materials.

[0211] In some embodiments, the separator 13 includes a base 15 and a plurality of support portions 14, the support portions 14 including organic particles disposed on the base.

[0212] The organic particles P can protrude from the base 15 as a whole. Alternatively, a portion of the organic particles is embedded in the base 15, and another portion protrudes from the base 15.

[0213] The organic particles P can support the positive electrode sheet 11 or the negative electrode sheet 12 to increase the gap G and provide space for expansion of the negative electrode sheet 12.

[0214] For simplicity of description, the base 15 of the separator 13 can be referred to as a separator base 131.

[0215] In some embodiments, the base 15 of the separator 13 includes a base film 13a and an inorganic particle layer P3 disposed on the base film 13a, and the organic particles P at least partially protrude from the inorganic particle layer P3.

[0216] The inorganic particle layer P3 includes a plurality of inorganic particles, and gaps are formed between the inorganic particles and the organic particles, which are sufficient and unevenly distributed, thereby improving the air permeability of the separator and providing better cycle performance and reliability of the cylindrical battery cell.

[0217] In some embodiments, the separator 13 includes a coating layer 13b disposed on at least one surface of the base film 13a. The coating layer 13b includes the inorganic particle layer P3 and the plurality of organic particles P.

[0218] In some examples, the inorganic particles can be coated on the base film 13a to form the inorganic particle layer P3, and then the plurality of organic particles can be coated on the inorganic particle layer P3. In other examples, the inorganic particles and the organic particles can be mixed and then coated together on the base film 13a.

[0219] In some examples, one surface of the base film 13a is coated with the coating layer 13b containing the inorganic particle layer P3 and the plurality of organic particles P, and the other surface of the base film 13a can be uncoated or coated with the inorganic particle layer P3. In other examples, both surfaces of the base film 13a are coated with the coating layer 13b containing the inorganic particle layer P3 and the organic particles P.

[0220] The sufficient and unevenly distributed voids between the inorganic particles and the organic particles P can improve the air permeability of the separator 13, and the cylindrical battery cell 7 has better cycle performance and reliability. The organic particles P can support the positive electrode sheet 11 or the negative electrode sheet 12 to increase the gap G and provide space for the expansion of the negative electrode sheet 12.

[0221] In some embodiments, the inorganic particles can include one or more of boehmite (γ-AlOOH), aluminum oxide (Al2O3), barium sulfate (BaSO4), magnesium oxide (MgO), magnesium hydroxide (Mg(OH)2), silicon dioxide (SiO2), tin dioxide (SnO2), titanium oxide (TiO2), calcium oxide (CaO), zinc oxide (ZnO), zirconium oxide (ZrO2), yttrium oxide (Y2O3), nickel oxide (NiO), cerium oxide (CeO2), zirconium titanate (SrTiO3), barium titanate (BaTiO3), and magnesium fluoride (MgF2).

[0222] In some embodiments, the volume average particle size Dv50 of the inorganic particles is ≤ 2.5 μm; for example, the particle size of the inorganic particles can be 0.5 μm-2.5 μm, 1.5 μm-2.5 μm, 0.3 μm-0.7 μm, etc.

[0223] In some embodiments, the surface of the base film 13a facing the positive electrode sheet 11 is coated with the coating layer 13b, and / or the surface of the base film 13a facing the negative electrode sheet 12 is coated with the coating layer 13b.

[0224] In some embodiments, the gap G extends along the winding direction V of the electrode assembly 10, and the gap G has a winding start end E1 and a winding end E2.

[0225] As an example, the positive electrode sheet 11 has a positive electrode winding start end E3 and a positive electrode winding end E4, and the negative electrode sheet 12 has a negative electrode winding start end E5 and a negative electrode winding end E6. Along the winding direction V, the negative electrode winding end E6 is beyond the positive electrode winding end E4; along the opposite direction of the winding direction V, the negative electrode winding start end E5 is beyond the positive electrode winding start end E3. The negative electrode sheet 12 is beyond the positive electrode sheet 11 at both ends along the winding direction V, and the negative electrode sheet 12 can provide an insertion space for the active ions released by the positive electrode sheet 11, thereby reducing the risk of ion release. In the radial direction of the cylindrical battery cell, the winding start end E1 of the gap G corresponds to the positive electrode winding start end E3, and the winding end E2 of the gap G corresponds to the positive electrode winding end E4.

[0226] FIG. 9 is a partial cross-sectional view of an electrode assembly of a cylindrical battery cell according to some embodiments of the present application; and FIG. 10 is a schematic view of a separator of the electrode assembly of the cylindrical battery cell according to some embodiments of the present application.

[0227] Referring to FIGS. 9 and 10, in some embodiments, the separator 13 is provided with a plurality of support portions 14 on both sides thereof. The gap G includes a first gap G1 formed between the positive electrode sheet 11 and the separator 13, and a second gap G2 formed between the negative electrode sheet 12 and the separator 13.

[0228] As an example, the first gap G1 has a radial dimension W1, and the second gap G2 has a radial dimension W2. The radial dimension W of the gap G is W1+W2.

[0229] In the thickness direction of the separator 13, the support portions 14 on both sides of the separator 13 can or can not overlap.

[0230] By providing a plurality of support portions 14 on both sides of the separator 13, the gap G can be increased, thereby providing more space for the expansion of the negative electrode sheet 12.

[0231] In some embodiments, the base film 13a is provided with a coating layer 13b on both sides thereof.

[0232] FIG. 11 is a partial cross-sectional view of an electrode assembly of a cylindrical battery cell according to some other embodiments of the present application; FIG. 12 is a schematic view of a positive electrode sheet of the electrode assembly in a flattened state according to some embodiments of the present application; FIG. 13 is a cross-sectional view of the positive electrode sheet of the electrode assembly according to some embodiments of the present application; and FIG. 14 is a cross-sectional view of a negative electrode sheet of the electrode assembly according to some embodiments of the present application.

[0233] Referring to FIGS. 11 to 14, in some embodiments, the positive electrode sheet 11 is provided with a support portion 14. In the embodiments of the present application, the positive electrode sheet 11 can be provided with a support portion 14 on one side thereof, or can be provided with a support portion 14 on both sides thereof.

[0234] In some embodiments, the positive tab 11 includes a positive base 111 and a plurality of positive protrusions 112 protruding from the surface of the positive base 111, and the positive tab 11 is provided with a plurality of positive recesses 113 corresponding to the positions of the positive protrusions 112 on the side away from the positive protrusions 112.

[0235] As an example, the support portion 14 of the positive tab 11 includes the positive protrusions 112.

[0236] As an example, the positive recesses 113 are provided in one-to-one correspondence with the positive protrusions 112.

[0237] The positive protrusions 112 can support the separator 13 and the negative tab 12, thereby forming the gap G. The positive recesses 113 can accommodate the electrolyte and also provide space for the expansion of the negative tab 12.

[0238] As an example, the positive protrusions 112 and the positive recesses 113 can be formed by stamping the positive tab 11.

[0239] In some embodiments, the surface of the positive protrusions 112 can be provided with organic particles.

[0240] In some embodiments, the positive lug is connected to the positive base 111.

[0241] In some embodiments, all of the positive protrusions 112 protrude toward the same side of the positive base 111. Correspondingly, the plurality of support portions 14 are provided on the same side of the positive base 111.

[0242] Embodiments of the present application can simplify the forming process of the positive tab 11.

[0243] In some embodiments, the positive protrusions 112 are a plurality of positive protrusions, a portion of the positive protrusions 112 protrude from the positive base 111 to a higher height, and another portion of the positive protrusions 112 protrude from the positive base 111 to a lower height. The first support portion includes the positive protrusions 112 protruding from the positive base 111 to the higher height, and the second support portion includes the positive protrusions 112 protruding from the positive base 111 to the lower height.

[0244] In some embodiments, the side of the separator 13 facing the positive recesses 113 is provided with a plurality of support portions 14, and at least a portion of the plurality of support portions 14 of the separator 13 does not overlap the positive recesses 113 in the radial direction.

[0245] In some embodiments, the positive tab 11 includes a positive current collector 11a and a positive film layer 11b provided on the surface of the positive current collector 11a. As an example, the portion of the positive current collector 11a on which the positive film layer 11b is not provided can be the positive lug.

[0246] In some embodiments, the positive electrode protrusion 112 is formed in a region of the positive electrode tab 11 provided with the positive electrode film layer 11b.

[0247] In some embodiments, the negative electrode tab 12 includes a negative electrode current collector 12a and a negative electrode film layer 12b provided on at least one side of the negative electrode current collector 12a and containing a negative electrode active material.

[0248] Exemplarily, the portion of the negative electrode current collector 12a not provided with the negative electrode film layer 12b can be a negative electrode ear.

[0249] In some embodiments, the negative electrode active material includes a silicon-based material. The introduction of the silicon-based material can improve the capacity of the negative electrode active material and increase the energy density of the cylindrical battery cell 7. The gap G can provide space for the expansion of the silicon-based material, thereby reducing the influence of the expansion force on the silicon-based material.

[0250] Exemplarily, the silicon-based material can include at least one of elemental silicon, a silicon oxide compound, a silicon-carbon composite, a silicon-nitrogen composite, and a silicon alloy.

[0251] In some embodiments, the mass content of silicon in the negative electrode film layer 12b is 2% to 19%. Exemplarily, the mass content of silicon in the negative electrode film layer can be 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, or a range formed by any two of the above values.

[0252] The mass content of silicon in the negative electrode film layer is a meaning known in the art and can be detected using devices and methods known in the art, for example, placing the negative electrode tab in a solvent (such as water) for soaking, separating the negative electrode active material from the negative electrode current collector, and obtaining each substance in the negative electrode film layer by suction filtration, taking the test sample, and using an inductively coupled plasma-optical emission spectrometer of ICAP7400 model of Thermo Fisher Scientific Company of the United States, and referring to the GB / T30902-2014 standard to obtain the content of silicon.

[0253] Embodiments of the present application limit the mass content of silicon in the negative electrode film layer 12b to be greater than or equal to 2% to improve the capacity of the negative electrode tab and increase the energy density of the cylindrical battery cell. The gap G can provide space for the expansion of the negative electrode tab, thereby reducing the influence of the expansion force on the silicon-based material. Embodiments of the present application limit the mass content of silicon in the negative electrode film layer 12b to be less than or equal to 19% to limit the expansion amount of the cylindrical battery cell and improve the cycle performance of the cylindrical battery cell.

[0254] The mass content of silicon in the negative electrode film layer 12b is limited to 2% to 19% in the embodiments of the present application, so as to balance the expansion and capacity of the negative electrode sheet to some extent, and take into account the cycle performance and energy density of the cylindrical battery cell.

[0255] In some embodiments, the mass content of silicon in the negative electrode film layer 12b is 6% to 13%.

[0256] In some embodiments, the capacity area density of the negative electrode sheet 12 is greater than or equal to 3.2 mAh / cm 2 .

[0257] The capacity area density of the negative electrode sheet is a meaning known in the art, which can be detected by using devices and methods known in the art, for example, the above-mentioned negative electrode sheet and metal lithium sheet are assembled into a pair of electrodes, matched with electrolyte and separator, and assembled into a CR2430 type button cell in an argon-protected glove box; after the obtained button cell is left standing for 12 h, it is discharged at 0.05C constant current to 0.005V at 25°C, left standing for 10 minutes, discharged at 50 μA constant current to 0.005V again, left standing for 10 minutes, and discharged at 10 μA constant current to 0.005V; then charged at 0.1C constant current to 2V, and the ratio of the charge capacity to the area of the negative electrode sheet is the capacity area density. As an example, the electrolyte and separator can be the electrolyte and separator of Example 1 described below.

[0258] The area density of the negative electrode sheet 12 is related to the expansion of the negative electrode sheet. By providing a gap, the influence of increasing the area density of the negative electrode sheet on the expansion force can be reduced, thereby improving the capacity of the negative electrode sheet and the energy density of the cylindrical battery cell.

[0259] For example, the capacity area density of the negative electrode sheet can be 3.2 mAh / cm 2 , 3.3 mAh / cm 2 , 3.33 mAh / cm 2 , 3.5 mAh / cm 2 , 3.8 mAh / cm 2 , 3.9 mAh / cm 2 , 4 mAh / cm 2 , 4.2 mAh / cm 2 , 4.5 mAh / cm 2 , 4.8 mAh / cm 2 , 4.9 mAh / cm 2 , 5 mAh / cm 2 , 5.2 mAh / cm 2 , 5.5 mAh / cm 2 , 5.8 mAh / cm 2 , 6 mAh / cm 2, 6.2 mAh / cm 2 , 6.5 mAh / cm 2 , 6.8 mAh / cm 2 , 7 mAh / cm 2 , 7.5 mAh / cm 2 , 8 mAh / cm 2 , 8.5 mAh / cm 2 , 9 mAh / cm 2 , 9.5 mAh / cm 2 , 10 mAh / cm 2 , 10.5 mAh / cm 2 , 11 mAh / cm 2 , 11.5 mAh / cm 2 , or a range defined by any two of the above values.

[0260] In some embodiments, the capacity area density of the negative electrode sheet 12 is 3.3 mAh / cm 2 to 11.5 mAh / cm 2 . The embodiments of the present application can balance the capacity and expansion of the negative electrode sheet to some extent, and take into account the energy density and cycle performance of the cylindrical battery cell.

[0261] In some embodiments, the capacity area density of the negative electrode sheet 12 is 3.96 mAh / cm 2 to 7.56 mAh / cm 2 . The embodiments of the present application can further take into account the energy density and cycle performance of the cylindrical battery cell.

[0262] In some embodiments, the negative electrode sheet 12 is provided with a plurality of support portions 14.

[0263] In the embodiments of the present application, the negative electrode sheet 12 can be provided with a plurality of support portions 14 on one side, or can be provided with a plurality of support portions 14 on both sides.

[0264] In some embodiments, the negative electrode sheet 12 includes a negative electrode base portion 121 and a plurality of negative electrode protrusions 122 protruding from the surface of the negative electrode base portion 121, and the negative electrode sheet 12 is provided with a negative electrode recess portion 123 corresponding to the negative electrode protrusions 122 on the side away from the negative electrode protrusions 122.

[0265] As an example, the support portion 14 of the negative electrode sheet 12 includes the negative electrode protrusion 122.

[0266] As an example, the negative electrode recess portion 123 is the same number as the negative electrode protrusion 122, and is provided one-to-one.

[0267] The negative protrusions 122 can support the separator 13 and the positive sheet 11, thereby forming the gap G. The negative recesses 123 can accommodate the electrolyte and can also provide space for expansion of the negative sheet 12.

[0268] As an example, the negative protrusions 122 and the negative recesses 123 can be formed by stamping the negative sheet 12.

[0269] In some embodiments, the surface of the negative protrusions 122 can be provided with organic particles.

[0270] In some embodiments, the negative tab is connected to the negative base 121.

[0271] In some embodiments, all of the negative protrusions 122 protrude toward the same side of the negative base 121. Correspondingly, the plurality of support portions 14 are arranged on the same side of the negative base 121.

[0272] Embodiments of the present application can simplify the forming process of the negative sheet 12.

[0273] In some embodiments, the negative protrusions 122 are a plurality, a part of the negative protrusions 122 protrude from the negative base 121 at a higher height, and another part of the negative protrusions 122 protrude from the negative base 121 at a lower height. The first support portion includes the negative protrusions 122 with the higher height, and the second support portion includes the negative protrusions 122 with the lower height.

[0274] In some embodiments, the side of the separator 13 facing the negative recesses 123 is provided with a plurality of support portions 14, and at least part of the plurality of support portions 14 of the separator 13 does not overlap the negative recesses 123 in the radial direction.

[0275] In some embodiments, the negative protrusions 122 are formed in the region of the negative sheet 12 provided with the negative film layer 12b.

[0276] In some embodiments, the gap G is formed between the negative film layer 12b and the positive film layer 11b.

[0277] In some embodiments, the side of the positive sheet 11 facing the separator 13 is provided with a plurality of support portions 14, the side of the separator 13 facing the positive sheet 11 is provided with a plurality of support portions 14, and the plurality of support portions 14 of the positive sheet 11 facing the separator 13 and the plurality of support portions 14 of the separator 13 facing the positive sheet 11 are arranged at least partially opposite to each other.

[0278] Optionally, the negative sheet 12 is not provided with support portions.

[0279] As an example, the positive sheet 11 is provided with separators 13 on both sides, the separator 13 located on the inner side of the positive sheet 11 is referred to as an inner separator, and the separator 13 located on the outer side of the positive sheet 11 is referred to as an outer separator.

[0280] In some examples, the positive electrode sheet 11 is provided with a plurality of support portions 14 on a side facing the inner separator, the inner separator is provided with a plurality of support portions 14 on a side facing the positive electrode sheet 11, and the plurality of support portions 14 of the positive electrode sheet 11 and the plurality of support portions 14 of the inner separator are at least partially oppositely arranged. For example, the plurality of positive electrode protrusions 112 of the positive electrode sheet 11 and the plurality of organic particles of the inner separator are at least partially oppositely arranged.

[0281] In other examples, the positive electrode sheet 11 is provided with a plurality of support portions 14 on a side facing the outer separator, the outer separator is provided with a plurality of support portions 14 on a side facing the positive electrode sheet 11, and the plurality of support portions 14 of the positive electrode sheet 11 and the plurality of support portions 14 of the outer separator are at least partially oppositely arranged. For example, the plurality of positive electrode protrusions 112 of the positive electrode sheet 11 and the plurality of organic particles of the outer separator are at least partially oppositely arranged.

[0282] In yet other examples, the positive electrode sheet 11 is provided with a plurality of support portions 14 on both sides. The inner separator is provided with a plurality of support portions 14 on a side facing the positive electrode sheet 11, and the outer separator is provided with a plurality of support portions 14 on a side facing the positive electrode sheet 11. The plurality of support portions 14 of the positive electrode sheet 11 facing the inner separator and the plurality of support portions 14 of the inner separator facing the positive electrode sheet 11 are at least partially oppositely arranged, and the plurality of support portions 14 of the positive electrode sheet 11 facing the outer separator and the plurality of support portions 14 of the outer separator facing the positive electrode sheet 11 are at least partially oppositely arranged.

[0283] By oppositely arranging the plurality of support portions 14 of the positive electrode sheet 11 and the plurality of support portions 14 of the separator 13, the plurality of support portions 14 of the positive electrode sheet 11 and the plurality of support portions 14 of the separator 13 can at least partially abut, so as to increase the gap G and provide more space for the expansion of the negative electrode sheet 12.

[0284] As an example, the embodiments of the present application can reduce the depth of the positive electrode recess 113 and the particle size of the organic particles, reduce the damage of the positive electrode sheet 11 during stamping, and improve the cycle life of the cylindrical battery cell 7.

[0285] In some embodiments, the negative electrode sheet 12 is provided with a plurality of support portions 14 on a side facing the separator 13, the separator 13 is provided with a plurality of support portions 14 on a side facing the negative electrode sheet 12, and the plurality of support portions 14 of the negative electrode sheet 12 facing the separator 13 and the plurality of support portions 14 of the separator 13 facing the negative electrode sheet 12 are at least partially oppositely arranged.

[0286] Optionally, the positive electrode sheet 11 is not provided with a support portion.

[0287] As an example, the negative electrode sheet 12 is provided with a separator 13 on both sides, the separator 13 located on the inner side of the negative electrode sheet 12 is referred to as an inner separator, and the separator 13 located on the outer side of the negative electrode sheet 12 is referred to as an outer separator.

[0288] In some examples, the negative electrode sheet 12 has a plurality of support portions 14 on a side facing the inner separator, the inner separator has a plurality of support portions 14 on a side facing the negative electrode sheet 12, and the plurality of support portions 14 of the negative electrode sheet 12 and the plurality of support portions 14 of the inner separator are at least partially arranged opposite to each other. For example, the plurality of negative electrode protrusions 122 of the negative electrode sheet 12 and the plurality of organic particles of the inner separator are at least partially arranged opposite to each other.

[0289] In other examples, the negative electrode sheet 12 has a plurality of support portions 14 on a side facing the outer separator, the outer separator has a plurality of support portions 14 on a side facing the negative electrode sheet 12, and the plurality of support portions 14 of the negative electrode sheet 12 and the plurality of support portions 14 of the outer separator are at least partially arranged opposite to each other. For example, the plurality of negative electrode protrusions 122 of the negative electrode sheet 12 and the plurality of organic particles of the outer separator are at least partially arranged opposite to each other.

[0290] In yet other examples, the negative electrode sheet 12 has a plurality of support portions 14 on both sides. The inner separator has a plurality of support portions 14 on a side facing the negative electrode sheet 12, and the outer separator has a plurality of support portions 14 on a side facing the negative electrode sheet 12. The plurality of support portions 14 of the negative electrode sheet 12 facing the inner separator and the plurality of support portions 14 of the inner separator facing the negative electrode sheet 12 are at least partially arranged opposite to each other, and the plurality of support portions 14 of the negative electrode sheet 12 facing the outer separator and the plurality of support portions 14 of the outer separator facing the negative electrode sheet 12 are at least partially arranged opposite to each other.

[0291] By arranging the plurality of support portions 14 of the negative electrode sheet 12 opposite to the plurality of support portions 14 of the separator 13, the plurality of support portions 14 of the negative electrode sheet 12 and the plurality of support portions 14 of the separator 13 are at least partially arranged opposite to each other, so as to increase the gap G and provide more space for the expansion of the negative electrode sheet 12.

[0292] As an example, the embodiments of the present application can reduce the depth of the negative electrode recess 123 and the particle size of the organic particles P, reduce the damage of the negative electrode sheet 12 during stamping, and improve the cycle life of the cylindrical battery cell 7.

[0293] In some embodiments, the negative electrode sheet 12 has a plurality of support portions 14 on a side facing the positive electrode sheet 11, the positive electrode sheet 11 has a plurality of support portions 14 on a side facing the negative electrode sheet 12, and the plurality of support portions 14 of the negative electrode sheet 12 facing the positive electrode sheet 11 and the plurality of support portions 14 of the positive electrode sheet 11 facing the negative electrode sheet 12 are at least partially arranged opposite to each other.

[0294] Optionally, the separator 13 is not provided with a support portion.

[0295] In some examples, the outer side of the positive electrode sheet 11 is provided with a plurality of support portions 14, and the inner side of the negative electrode sheet 12 is provided with a plurality of support portions 14. The plurality of support portions 14 on the outer side of the positive electrode sheet 11 and the plurality of support portions 14 on the inner side of the negative electrode sheet 12 are arranged to face each other and overlap in the radial direction.

[0296] In some examples, the inner side of the positive electrode sheet 11 is provided with a plurality of support portions 14, and the outer side of the negative electrode sheet 12 is provided with a plurality of support portions 14. The plurality of support portions 14 on the inner side of the positive electrode sheet 11 and the plurality of support portions 14 on the outer side of the negative electrode sheet 12 are arranged to face each other and overlap in the radial direction.

[0297] In some examples, the inner side and the outer side of the positive electrode sheet 11 are both provided with a plurality of support portions 14, and the inner side and the outer side of the negative electrode sheet 12 are both provided with a plurality of support portions 14. The plurality of support portions 14 on the outer side of the positive electrode sheet 11 and the plurality of support portions 14 on the inner side of the negative electrode sheet 12 are arranged to face each other and overlap in the radial direction, and the plurality of support portions 14 on the inner side of the positive electrode sheet 11 and the plurality of support portions 14 on the outer side of the negative electrode sheet 12 are arranged to face each other and overlap in the radial direction.

[0298] By arranging the plurality of support portions 14 on the negative electrode sheet 12 to face the plurality of support portions 14 on the positive electrode sheet 11, the plurality of support portions 14 on the negative electrode sheet 12 and the plurality of support portions 14 on the positive electrode sheet 11 can support each other, so as to increase the gap G and provide more space for the expansion of the negative electrode sheet 12.

[0299] As an example, the embodiments of the present application can reduce the depth of the negative electrode recess 123 and the depth of the positive electrode recess 113, reduce the damage of the positive electrode sheet 11 and the negative electrode sheet 12 during stamping, and improve the cycle life of the cylindrical battery cell 7.

[0300] In some embodiments, the positive electrode sheet 11, the negative electrode sheet 12, and the separator 13 are all provided with a plurality of support portions 14.

[0301] Optionally, the separator 13 is provided with a plurality of support portions 14 on both sides.

[0302] Optionally, the outer side of the positive electrode sheet 11 is provided with a plurality of support portions 14, and the inner side of the negative electrode sheet 12 is provided with a plurality of support portions 14; alternatively, the inner side of the positive electrode sheet 11 is provided with a plurality of support portions 14, and the outer side of the negative electrode sheet 12 is provided with a plurality of support portions 14.

[0303] FIG. 15 is a cross-sectional view of a positive electrode sheet according to some embodiments of the present application.

[0304] Referring to FIG. 15, in some embodiments, the positive electrode sheet 11 includes a positive electrode base 111 and a plurality of support portions 14, and the support portions 14 include organic particles arranged on the positive electrode base 111.

[0305] The organic particles P can protrude from the positive electrode base 111 as a whole. Alternatively, a part of the organic particles is embedded in the positive electrode base 111, and another part protrudes from the positive electrode base 111.

[0306] The organic particles P of the positive electrode sheet 11 can support the negative electrode sheet 12 to increase the gap G and provide space for expansion of the negative electrode sheet 12.

[0307] In some embodiments, the positive electrode base 111 includes a positive electrode current collector 11a, a positive electrode film layer 11b disposed on a surface of the positive electrode current collector 11a, and an inorganic particle layer P3 coated on a surface of the positive electrode film layer 11b facing away from the positive electrode current collector. The organic particles P at least partially protrude from the inorganic particle layer P3.

[0308] The positive electrode film layer 11b includes a positive electrode active material, and the inorganic particle layer P3 includes a plurality of inorganic particles.

[0309] In some embodiments, a part of the organic particles P is embedded in the inorganic particle layer P3, and another part protrudes from the inorganic particle layer P3.

[0310] In some embodiments, the positive electrode sheet 11 includes a positive electrode particle coating layer 11c disposed on a surface of the positive electrode film layer 11b. The positive electrode particle coating layer 11c includes the inorganic particle layer P3 and a plurality of organic particles P.

[0311] In some examples, the inorganic particles can be coated on the positive electrode film layer 11b to form the inorganic particle layer P3 first, and then the plurality of organic particles can be coated on the inorganic particle layer P3. In other examples, the inorganic particles and the organic particles can be mixed together and then coated on the positive electrode film layer 11b.

[0312] As an example, the positive electrode particle coating layer 11c does not include a positive electrode active material.

[0313] In some embodiments, the plurality of organic particles P includes first organic particles P1 and second organic particles P2, and a number average particle size of the first organic particles P1 is greater than a number average particle size of the second organic particles P2.

[0314] FIG. 16 is a cross-sectional schematic view of a negative electrode sheet according to some embodiments of the present application.

[0315] Referring to FIG. 16, in some embodiments, the negative electrode sheet 12 includes a negative electrode base 121 and a plurality of support portions 14, and the support portions 14 include organic particles P disposed on the negative electrode base 121.

[0316] The organic particles P can protrude from the negative electrode base 121 as a whole. Alternatively, a part of the organic particles is embedded in the negative electrode base 121, and another part protrudes from the negative electrode base 121.

[0317] The organic particles P of the negative sheet 12 can support the positive sheet 11 to increase the gap G and provide space for expansion of the negative sheet 12.

[0318] In some embodiments, the negative base 121 includes a negative current collector 12a, a negative film layer 12b disposed on a surface of the negative current collector 12a, and an inorganic particle layer P3 coated on a surface of the negative film layer 12b away from the negative current collector 12a. The organic particles P at least partially protrude from the inorganic particle layer P3.

[0319] The negative film layer 12b includes a negative active material, and the inorganic particle layer P3 includes a plurality of inorganic particles.

[0320] In some embodiments, a portion of the organic particles P is embedded in the inorganic particle layer P3, and a portion of the organic particles P protrudes from the inorganic particle layer P3.

[0321] In some embodiments, the negative sheet 12 includes a negative particle coating layer 12c disposed on a surface of the negative film layer 12b. The negative particle coating layer 12c includes the inorganic particle layer P3 and the plurality of organic particles P.

[0322] In some examples, the inorganic particle layer P3 can be formed on the negative film layer 12b first, and then the plurality of organic particles can be coated on the inorganic particle layer P3. In other examples, the inorganic particles and the organic particles can be mixed together and then coated on the negative film layer 12b.

[0323] As an example, the negative particle coating layer 12c does not include a negative active material.

[0324] In some embodiments, the plurality of organic particles P includes first organic particles P1 and second organic particles P2, and a number average particle size of the first organic particles P1 is greater than a number average particle size of the second organic particles P2.

[0325] FIG. 17 is a partial cross-sectional view of an electrode assembly of a cylindrical battery cell according to some embodiments of the present application. FIG. 17 shows one circle of positive sheets, one circle of negative sheets, and one circle of separators.

[0326] In some embodiments, the gap G1 has a winding start end E1 and a winding end E2. A radial dimension of a portion of the gap G close to the winding start end E1 is greater than or equal to a radial dimension of a portion of the gap G close to the winding end E2.

[0327] In the embodiments of the present application, the radial dimensions of different portions of the gap G along the winding direction V are compared in the same cross-section perpendicular to the axial direction Z.

[0328] The "portion of the gap G close to the winding start end E1" does not require extending from the winding start end E1. As an example, the "portion of the gap G close to the winding start end E1" can extend from a position 1-5 turns away from the winding start end in the winding direction V.

[0329] The "portion of the gap G close to the winding end end E2" does not require extending to the winding end end E2 in the winding direction V. As an example, the "portion of the gap G close to the winding end end E2" can have a tail end in the winding direction V that is 1-5 turns away from the winding end end.

[0330] In embodiments of the present application, the portion of the gap G close to the winding start end E1 has a larger radial dimension to provide more expansion space for the negative electrode sheet 12 in the middle of the electrode assembly 10, reduce the risk of the middle of the electrode assembly 10 collapsing due to expansion, and improve the cycle performance of the cylindrical battery cell 7.

[0331] In some embodiments, the gap G extends in the winding direction V and is wound into n turns, each turn being defined as a winding turn, and n≥20. The average of the radial dimensions of the 5th-9th winding turns is greater than the average of the radial dimensions of the n-9th to n-5th winding turns.

[0332] It is explained herein that n does not require being an integer, in other words, the 1st to n-1th winding turns are all complete turns; the portion from the end of the n-1th winding turn to the winding end end E2 can or can not be a complete turn, for example, 1 / 4 turn, 1 / 2 turn, or 3 / 4 turn.

[0333] In embodiments of the present application, the portion of the gap G close to the winding start end E1 has a larger radial dimension to provide more expansion space for the negative electrode sheet 12 in the middle of the electrode assembly 10, reduce the risk of the middle of the electrode assembly 10 collapsing due to expansion, and improve the cycle performance of the cylindrical battery cell 7.

[0334] In some embodiments, the radial dimension of at least part of the gap G gradually decreases in the winding direction V.

[0335] The gradual change in the radial dimension of the gap G reduces the abrupt change in the radial dimension of the gap G, reduces the stress concentration of the negative electrode sheet 12, and improves the cycle performance of the cylindrical battery cell 7.

[0336] FIG. 18 is a partial cross-sectional view of an electrode assembly of a cylindrical battery cell according to some embodiments of the present application.

[0337] Referring to FIG. 18, in some embodiments, the gap G includes a middle region C1 and two end regions C2 arranged in the axial direction Z of the cylindrical battery cell, the middle region C1 being located between the two end regions C2, and the radial dimension of the middle region C1 being smaller than the radial dimension of the end regions C2.

[0338] In the embodiments of the present application, the radial dimension of the middle region C1 and the radial dimension of the end region C2 are compared in a cross section of one winding turn parallel to the axial direction Z.

[0339] The gap G has a first end E7 and a second end E8 oppositely arranged along the axial direction Z; the dimension of the gap G along the axial direction Z is defined as L, i.e. the distance between the first end E7 and the second end E8 along the axial direction Z is L.

[0340] The end region C2 is a region having a certain dimension along the axial direction Z. One end region C2 is a region extending to a length L1 from the first end E7 towards the second end E8, and the other end region C2 is a region extending to a length L1 from the second end E8 towards the first end E7; the middle region C1 includes a region extending to a length L2 from the middle cross section S towards the first end E7 and a region extending to a length L2 from the middle cross section S towards the second end E8. The middle cross section S is a cross section perpendicular to the axial direction Z; along the axial direction Z, the distance between the middle cross section S and the first end E7 is equal to the distance between the middle cross section S and the second end E8.

[0341] Exemplarily, L1 / L is 0.1-0.3, and can be 0.2. Exemplarily, L2 / L is 0.03-0.2, and can be 0.1.

[0342] Exemplarily, L1 can be 20 mm, and L2 can be 5 mm.

[0343] Exemplarily, the minimum radial dimension of the end region C2 is greater than the maximum radial dimension of the middle region C1.

[0344] In the embodiments of the present application, the end region C2 has a larger radial dimension, so as to facilitate the electrolyte to enter the gap G, improve the wetting effect of the electrolyte on the electrode sheet, and improve the cycle performance of the cylindrical battery cell 7.

[0345] In some embodiments, the radial dimension of the middle region is 5 μm-60 μm, and can be 10 μm-30 μm.

[0346] In some embodiments, the gap G further includes a transition region C3 connecting the middle region C1 and the end region C2.

[0347] In some embodiments, the radial dimension of the gap G gradually decreases in the direction from the end region C2 to the middle region C1, so as to reduce the sudden change of the radial dimension of the gap G, reduce the stress concentration of the negative electrode sheet 12, and improve the cycle performance of the cylindrical battery cell 7.

[0348] FIG. 19 is a cross-sectional view of the battery cell shown in FIG. 4; and FIG. 20 is an enlarged view of the circle frame in FIG. 19.

[0349] Referring to FIGS. 4, 5, 19, and 20, in some embodiments, one of the positive tab 11 and the negative tab 12 includes the first tab 10a, and the other includes the second tab 10b. In other words, one of the first tab 10a and the second tab 10b is a positive tab, and the other is a negative tab.

[0350] The first tab 10a and the second tab 10b can be located at the same end of the electrode assembly 10 along the axial direction Z, or can be located at two ends of the electrode assembly 10 along the axial direction Z, respectively.

[0351] In some embodiments, the portion of the positive tab 11 having the positive film layer, the portion of the negative tab 12 having the negative film layer, and the separator 13 constitute an electrode body 10c of the electrode assembly 10. The first tab 10a and the second tab 10b are drawn out from one end of the electrode body 10c, or are drawn out from two ends of the electrode body 10c, respectively.

[0352] In some embodiments, the first tab 10a is wound into multiple turns along the winding direction. Optionally, the end portion of the first tab 10a is bent by a kneading or smoothing process, and forms a multi-layer structure stacked in the axial direction Z.

[0353] In some embodiments, the second tab 10b is wound into multiple turns along the winding direction. Optionally, the end portion of the second tab 10b is bent by a kneading or smoothing process, and forms a multi-layer structure stacked in the axial direction Z.

[0354] In some embodiments, the cylindrical battery cell 7 includes a first electrode lead-out portion 7a and a second electrode lead-out portion 7b, the first electrode lead-out portion 7a being electrically connected to the first tab 10a, and the second electrode lead-out portion 7b being electrically connected to the second tab 10b. The first electrode lead-out portion 7a and the second electrode lead-out portion 7b are insulated from each other.

[0355] The first electrode lead-out portion 7a and the second electrode lead-out portion 7b are used to be connected with an external circuit to achieve charging or discharging of the cylindrical battery cell 7. Exemplarily, when a plurality of cylindrical battery cells 7 are assembled into a group, the first electrode lead-out portion 7a and the second electrode lead-out portion 7b are used to be connected with a current lead member.

[0356] The first electrode lead-out portion 7a can be an electrode terminal 30 provided on the outer shell 20. The electrode terminal 30 is independently formed with the outer shell 20 and assembled together in the production process of the cylindrical battery cell 7. Exemplarily, the electrode terminal 30 is insulatively provided on the end cover 22 or the shell 21.

[0357] Alternatively, the first electrode lead-out portion 7a can also be a part of the outer shell 20. For example, the first electrode lead-out portion 7a can be the end cover 22 of the outer shell 20, or the first electrode lead-out portion 7a can be the end wall 211 of the shell 21 opposite to the end cover 22.

[0358] The second electrode lead-out portion 7b can be an electrode terminal 30 provided on the shell 20. Alternatively, the second electrode lead-out portion 7b can be a part of the shell 20. For example, the second electrode lead-out portion 7b can be an end cover 22 of the shell 20, or the second electrode lead-out portion 7b can be an end wall 211 of the shell 21 opposite to the end cover 22.

[0359] In some embodiments, the first electrode lead-out portion 7a and the second electrode lead-out portion 7b are located on the same side of the electrode assembly 10 in the axial direction Z of the cylindrical battery cell.

[0360] When a plurality of cylindrical battery cells 7 are assembled into a group, the first electrode lead-out portion 7a and the second electrode lead-out portion 7b of the plurality of cylindrical battery cells 7 can be arranged on the same side, facilitating the connection of the current collecting member to the first electrode lead-out portion 7a and the second electrode lead-out portion 7b and simplifying the battery structure.

[0361] In some embodiments, the shell 20 includes a shell 21 and an end cover 22, the shell 21 includes an integrally formed side wall 212 and an end wall 211, the end wall 211 and the end cover 22 are opposite in the axial direction Z of the cylindrical battery cell, and the end cover 22 is sealingly connected to the side wall 212.

[0362] The end cover 22 can be insulated from the side wall 212 or electrically connected.

[0363] The shell 21 has an opening at an end away from the end wall 211, and the end cover 22 covers the opening of the shell 21.

[0364] In some embodiments, one of the positive electrode sheet 11 and the negative electrode sheet 12 includes a first tab 10a, and the other includes a second tab 10b. The cylindrical battery cell 7 further includes an electrode terminal 30 insulated from the end wall 211, one of the first tab 10a and the second tab 10b is electrically connected to the electrode terminal 30, and the other is electrically connected to the end wall 211.

[0365] For example, the first tab 10a is electrically connected to the electrode terminal 30, and the second tab 10b is electrically connected to the end wall 211. The second tab 10b can be directly connected to the end wall 211 or indirectly connected to the end wall 211 through the end cover 22, the side wall 212, or other components.

[0366] One of the electrode terminal 30 and the end wall 211 serves as the first electrode lead-out portion 7a, and the other serves as the second electrode lead-out portion 7b.

[0367] The electrode terminal 30 and the end wall 211 can serve as two exposed electrodes of the cylindrical battery cell 7, and the electrode terminal 30 and the end wall 211 are located on the same side, facilitating the assembly of a plurality of cylindrical battery cells 7 into a group and simplifying the battery structure.

[0368] In some embodiments, the cylindrical battery cell 7 further comprises a first current collecting member 40 located on the side of the first tab 10a facing the end wall 211 and connected to the first tab 10a. The electrode terminal 30 abuts against and is connected to the surface of the first current collecting member 40 facing the end wall 211.

[0369] The first current collecting member 40 can function as an adapter to achieve electrical connection between the first tab 10a and the electrode terminal 30.

[0370] In some embodiments, the first current collecting member 40 is in the shape of a ring.

[0371] In some embodiments, the side of the electrode terminal 30 facing the first current collecting member 40 is provided with a terminal recess 31. The bottom wall of the terminal recess 31 is welded to the first current collecting member 40.

[0372] By providing the terminal recess 31, the thickness of the bottom wall of the terminal recess 31 can be reduced, the power required for welding the electrode terminal 30 and the first current collecting member 40 from the outside can be reduced, the risk of particles generated by welding falling into the housing 20 can be reduced, and the reliability of the cylindrical battery cell 7 can be improved.

[0373] Providing the terminal recess 31 on the inner side of the electrode terminal 30 can also increase the internal space of the cylindrical battery cell 7.

[0374] In some embodiments, the side of the electrode terminal 30 facing away from the first current collecting member 40 is provided with a terminal recess 31.

[0375] In some embodiments, the side of the electrode terminal 30 facing the first current collecting member 40 is provided with one terminal recess 31, and the side of the electrode terminal 30 facing away from the first current collecting member 40 is provided with another terminal recess 31; the bottom surfaces of the two terminal recesses 31 are welded to the first current collecting member 40 at corresponding positions.

[0376] In some embodiments, the bottom wall of the terminal recess 31 is provided with a through hole 32, which can be used for injecting electrolyte.

[0377] In some embodiments, the cylindrical battery cell 7 further comprises a cover plate 50 connected to the electrode terminal 30 and used to separate the through hole 32 from the external space of the cylindrical battery cell 7.

[0378] In some embodiments, at least part of the cover plate 50 is accommodated in the terminal recess 31. In some embodiments, the first electrode lead-out part comprises the cover plate 50 and the electrode terminal 30.

[0379] In some embodiments, the electrode terminal 30 is riveted to the end wall 211.

[0380] In some embodiments, the first tab 10a is located at one end of the electrode assembly 10 facing the end wall 211, and the second tab 10b is located at one end of the electrode assembly 10 facing the end cover 22. The cylindrical battery cell 7 further comprises a second current collecting member 60 connected to the second tab 10b; the second current collecting member 60 is connected to at least one of the end cover 22 and the side wall 212.

[0381] In some examples, the second current collecting member 60 is connected to the end cover 22, and the end cover 22 is electrically connected to the side wall 212. The second tab 10b is electrically connected to the end wall 211 through the second current collecting member 60, the end cover 22, and the side wall 212.

[0382] In other examples, the second current collecting member 60 is connected to the side wall 212. The second tab 10b is electrically connected to the end wall 211 through the second current collecting member 60 and the side wall 212. Optionally, the end cover 22 is provided in an insulating manner with the side wall 212.

[0383] In some embodiments, the shell 20 comprises a side wall 212 provided around the electrode assembly 10, the thickness of the side wall 212 is 0.3mm to 1.5mm, and the material of the side wall 212 comprises steel.

[0384] For example, the thickness of the side wall 212 is 0.3mm, 0.31mm, 0.32mm, 0.33mm, 0.35mm, 0.38mm, 0.40mm, 0.42mm, 0.45mm, 0.5mm, 0.55mm, 0.6mm, 0.65mm, 0.7mm, 0.75mm, 0.8mm, 0.85mm, 0.9mm, 0.95mm, 1mm, 1.05mm, 1.1mm, 1.15mm, 1.2mm, 1.3mm, 1.35mm, 1.4mm, 1.45mm, or 1.5mm.

[0385] In the embodiments of the present application, the thickness of the side wall 212 is in the meaning known in the art, and can be detected by using devices and methods known in the art, for example, a micrometer or a vernier caliper can be used for measurement.

[0386] For example, the material of the side wall 212 comprises stainless steel.

[0387] By providing the gap G, the present application can reduce the expansion force exerted by the electrode assembly 10 on the side wall 212, and therefore, the steel side wall 212 can have a thickness less than or equal to 1.5mm, thereby improving the energy density of the cylindrical battery cell 7. The thickness of the steel side wall 212 is greater than or equal to 0.3mm, so as to reduce the risk of deformation and rupture of the side wall 212 under the expansion force of the electrode assembly 10, and improve the reliability of the cylindrical battery cell 7.

[0388] The mechanical strength of the side wall 212 is relatively high and is not easy to deform, which is suitable for use with the silicon-containing negative electrode sheet 12 and is beneficial to improving the energy density of the battery monomer and making the battery monomer have excellent use reliability.

[0389] In some embodiments, the thickness of the side wall 212 is 0.3 mm to 1.2 mm.

[0390] In some embodiments, the thickness of the side wall 212 is 0.3 mm to 0.9 mm, and optionally 0.3 mm to 0.6 mm.

[0391] In some embodiments, the capacity area density of the negative electrode sheet is greater than or equal to 3.2 mAh / cm 2 The base material of the side wall 212 includes steel, and the thickness of the side wall 212 is 0.3 mm to 0.9 mm. The negative electrode sheet with the above capacity area density and the side wall 212 with the above thickness are used together, which is beneficial to improving the energy density of the battery monomer 7, making the battery monomer 7 have excellent use reliability, and improving the cycle performance.

[0392] In some embodiments, the material of the end wall 211 is the same as that of the side wall 212.

[0393] In some embodiments, the material of the end cover 22 is steel.

[0394] In some embodiments, the height of the shell 20 is 1.3 times to 4 times the diameter of the shell 20. Exemplarily, the height of the shell 20 can be the dimension of the shell 20 along the axial direction Z.

[0395] Optionally, the height of the shell 20 is 1.3 times, 1.4 times, 1.5 times, 1.6 times, 1.7 times, 1.8 times, 1.9 times, 2.0 times, 2.1 times, 2.2 times, 2.3 times, 2.4 times, 2.5 times, 2.6 times, 2.7 times, 2.8 times, 2.9 times, 3.0 times, 3.1 times, 3.2 times, 3.3 times, 3.4 times, 3.5 times, 3.6 times, 3.7 times, 3.8 times, 3.9 times, or 4.0 times the diameter of the shell 20.

[0396] When the shell 20 meets the above size requirements, the structural stability of the shell 20 is relatively high, which can improve the use reliability of the cylindrical battery monomer 7.

[0397] In some embodiments, the height of the shell 20 is 1.5 times to 2.5 times the diameter of the shell 20.

[0398] In some embodiments, the height of the housing 20 is 50mm to 150mm. For example, the height of the housing 20 is 50mm, 55mm, 60mm, 65mm, 70mm, 75mm, 80mm, 85mm, 90mm, 95mm, 100mm, 105mm, 110mm, 115mm, 120mm, 125mm, 130mm, 135mm, 140mm, 145mm or 150mm.

[0399] Optionally, the height of the housing 20 is 60mm to 100mm.

[0400] In some embodiments, the diameter of the housing 20 is 45mm to 80mm. For example, the diameter of the housing 20 is 45mm, 50mm, 55mm, 60mm, 65mm, 70mm, 75mm or 80mm.

[0401] Optionally, the diameter of the housing 20 is 45mm to 60mm.

[0402] Figure 21 is a schematic view of a partial cross-section of a battery cell according to some embodiments of the application.

[0403] Referring to Figure 21, in some embodiments, the first tab 10a and the second tab 10b are both located at one end of the electrode assembly 10 facing the end wall 211. The first tab 10a and the second tab 10b can share space in the axial direction Z, thereby improving space utilization and increasing energy density.

[0404] In some embodiments, the cylindrical battery cell 7 includes two electrode terminals 30 disposed at the end wall 211, and the first tab 10a and the second tab 10b are electrically connected to the two electrode terminals 30 respectively. The two electrode terminals 30 are the first electrode lead-out portion 7a and the second electrode lead-out portion 7b respectively.

[0405] Optionally, the cylindrical battery cell 7 includes a first current collecting member 40 and a second current collecting member 60, the first current collecting member 40 connects the first tab 10a and one of the electrode terminals 30, and the second current collecting member 60 connects the second tab 10b and the other electrode terminal 30.

[0406] In other embodiments, the cylindrical battery cell includes one electrode terminal disposed at the end wall, the first tab is electrically connected to the electrode terminal, and the second tab is electrically connected to the end wall.

[0407] In some embodiments, the projection of the first tab 10a along the axial direction Z is a sector.

[0408] In some embodiments, the projection of the second tab 10b along the axial direction Z is a sector.

[0409] According to some embodiments of the present application, the present application also provides a battery comprising a plurality of cylindrical battery cells 7 of any of the above embodiments.

[0410] According to some embodiments of the present application, the present application also provides an electric device comprising a cylindrical battery cell 7 of any of the above embodiments, the cylindrical battery cell 7 being configured to provide electric energy for the electric device. The electric device can be any of the devices or systems mentioned above.

[0411] Referring to FIGS. 4-9, the present application provides a cylindrical battery cell 7 comprising a housing 20, an electrode assembly 10, an electrode terminal 30, a first current collector 40, and a second current collector 60.

[0412] The housing 20 comprises a shell 21 and an end cap 22, the shell 21 comprising an integral side wall 212 and an end wall 211, the end wall 211 and the end cap 22 being opposite along an axial direction Z of the cylindrical battery cell, and the end cap 22 being welded to the side wall 212.

[0413] The electrode terminal 30 is insulatively disposed on the end wall 211.

[0414] At least a portion of the electrode assembly 10 is accommodated in the housing 20. The electrode assembly 10 comprises a positive electrode sheet 11, a negative electrode sheet 12, and a separator 13, the positive electrode sheet 11, the negative electrode sheet 12, and the separator 13 being wound together, and the separator 13 separating the positive electrode sheet 11 and the negative electrode sheet 12.

[0415] The positive electrode sheet 11 has a first tab 10a at an end thereof facing the end wall 211, the first current collector 40 connecting the electrode terminal 30 and the first tab 10a, and the negative electrode sheet 12 has a second tab 10b at an end thereof facing the end cap 22, the second current collector 60 connecting the first tab 10a and the end cap 22.

[0416] The positive electrode sheet 11 comprises a positive electrode base 111 and a positive electrode protrusion 112 protruding from a surface of the positive electrode base 111, and the positive electrode sheet 11 is provided with a positive electrode recess 113 corresponding to a position of the positive electrode protrusion 112 at a side thereof away from the positive electrode protrusion 112.

[0417] The separator 13 comprises a base film 13a and a coating layer 13b disposed on at least one surface of the base film 13a. The coating layer 13b comprises an inorganic particle layer P3 and a plurality of organic particles P, the organic particles P being partially embedded in the inorganic particle layer P3. The organic particles P and the positive electrode protrusion 112 are capable of supporting the negative electrode sheet 12 to form a gap G between the positive electrode sheet 11 and the negative electrode sheet 12. The gap has a radial dimension of 5-60 μm.

[0418] Embodiments

[0419] The following examples describe the present application in more detail, which are only used for illustrative purposes, because various modifications and changes within the scope of the present application are obvious to those skilled in the art. Unless otherwise stated, all parts, percentages and ratios reported in the following examples are based on mass, and all reagents used in the examples are commercially available or synthesized according to conventional methods and used directly without further purification, and the instruments used in the examples are commercially available.

[0420] Example 1

[0421] 1. Preparation of positive electrode sheet

[0422] The positive electrode sheet comprises a positive electrode current collector and a positive electrode film layer, the positive electrode film layer is located on both sides of the positive electrode current collector, the positive electrode current collector is an aluminum foil, and the positive electrode film layer is a film layer formed by uniformly coating a positive electrode slurry (the solvent is N-methyl pyrrolidone NMP) on the surface of the positive electrode current collector aluminum foil, and then drying and cold pressing, the positive electrode film layer comprises positive electrode active material, conductive agent carbon black (Super P) and binder polyvinylidene fluoride (PVDF) in a weight ratio of 97:1:2.

[0423] The positive electrode active material comprises a layered transition metal oxide with a molecular formula of LiNi 0.8 Co 0.1 Mn 0.1 O2(NCM811).

[0424] 2. Preparation of negative electrode sheet

[0425] The negative electrode sheet comprises a negative electrode current collector and a negative electrode film layer, the negative electrode film layer is located on both sides of the negative electrode current collector, the negative electrode current collector is a copper foil, and the negative electrode film layer is a film layer formed by uniformly coating a negative electrode slurry (the solvent is deionized water) on the surface of the negative electrode current collector copper foil, and then drying and cold pressing, the negative electrode film layer comprises silicon-based material (specifically silicon oxide compound), graphite, conductive agent carbon black, conductive agent carbon nanotube and binder polyacrylic acid in a weight ratio of 12.6:82.4:1.9:0.1:3.

[0426] The negative electrode film layer has an area density of 9.0 mg / cm 2 , a porosity of 22.1%, and a compacted density of 1.7 g / cm 3 .

[0427] 3. Separator

[0428] A PE (polyethylene) based film is provided.

[0429] Preparation of the coating slurry: Inorganic alumina (Al2O3) particles, first organic particles (vinylidene fluoride-hexafluoropropylene copolymer with a number average molecular weight of 550,000), second organic particles (styrene-vinyl acetate-pyrrolidone copolymer with a number average molecular weight of 80,000), dispersant sodium carboxymethyl cellulose (CMC-Na), and wetting agent silicone-modified polyether are mixed evenly in an appropriate amount of deionized water at a dry weight ratio of 70:20:8:1:1 to obtain a coating slurry with a solid content of 38% (by weight). The inorganic alumina (Al2O3) particles have a volume average particle size (Dv50) of 1 μm, the first organic particles are secondary particles with a number average particle size of 15 μm, and the second organic particles are primary particles with a number average particle size of 2 μm.

[0430] The coating slurry is applied to the two surfaces of the PE base film, and the separator is obtained through processes such as drying and slitting.

[0431] 4. Preparation of electrolyte

[0432] The electrolyte consists of an organic solvent and a lithium salt. Ethyl carbonate (EC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC) are mixed in a volume ratio of 1:1:1 to obtain an organic solvent. Then, fully dried lithium salt LiPF6 is dissolved in the mixed organic solvent to prepare an electrolyte with a lithium salt concentration of 1 mol / L.

[0433] 5. Preparation of cylindrical battery cells

[0434] The positive electrode, separator, and negative electrode are stacked in sequence, with the separator positioned between the positive and negative electrodes to provide isolation. The positive electrode, separator, and negative electrode are then wound to form an electrode assembly. This assembly is placed in a cylindrical shell, dried, and then injected with electrolyte. After vacuum sealing, settling, formation, and shaping, a cylindrical battery cell is obtained. The electrode assembly and the shell are both cylindrical, comprising a housing and end caps. The housing includes integrally formed sidewalls and end walls, with the sidewalls surrounding the electrode assembly. The end caps and end walls are axially aligned with the housing. The cylindrical battery cell has a diameter of 46 mm and a height of 95 mm.

[0435] Performance testing

[0436] 1. Battery cell expansion volume test

[0437] A cylindrical cell with 0% charge is immersed in silicone oil, and its mass is measured as m0.

[0438] A cylindrical cell in a 100% charged state is immersed in silicone oil, and its mass is measured as m1.

[0439] The density of silicone oil is ρ 硅油The volume change AV of the cylindrical battery cell between 100% state of charge and 0% state of charge is AV = (m0- m1) / p 硅油 The use reliability of the cylindrical battery cell is evaluated by AV. The smaller the AV, the smaller the volume expansion of the cylindrical battery cell, and the higher the use reliability. The larger the AV, the larger the volume expansion of the cylindrical battery cell, and the worse the use reliability.

[0440] The cylindrical battery cell is discharged at 0.33C to 2.5V at 25°C, and then discharged at 0.1C to 2.5V, at which time the cylindrical battery cell is at 0% state of charge. The cylindrical battery cell is charged at 0.33C to 4.25V at 25°C, and then charged at 0.1C to 4.25V, at which time the cylindrical battery cell is at 100% state of charge.

[0441] 2. Energy density test of the cylindrical battery cell

[0442] The first cycle discharge capacity (Ah) is multiplied by the ratio of the discharge voltage to the mass of the cylindrical battery cell at a constant voltage (4.25V in Example 1).

[0443] The energy density = first cycle discharge capacity (Ah) x discharge voltage (4.25V) / mass of the cylindrical battery cell (kg). The first cycle discharge capacity is tested according to the following steps: the cylindrical battery cell prepared above is fully charged at 1C and then fully discharged at 1C at 45°C, which is one cycle of charging and discharging, and the discharge capacity at this time is recorded, which is the first cycle discharge capacity.

[0444] 3. Cycle performance test of the battery

[0445] The cylindrical battery cell prepared above is fully charged at 1C and then fully discharged at 1C at 45°C, which is one cycle of charging and discharging, and the discharge capacity at this time is recorded, which is the first cycle discharge capacity. The cylindrical battery cell is tested for cycle charging and discharging according to the above method, and the discharge capacity after each cycle is recorded until the discharge capacity of the cylindrical battery cell decays to 80% of the initial discharge capacity, and the cycle number at this time is used to represent the cycle performance of the cylindrical battery cell. The higher the cycle number of the cylindrical battery cell, the better the cycle performance.

[0446] Examples 2-5

[0447] The battery cell is prepared by a method similar to Example 1, except that the preparation of the negative electrode sheet in Examples 2-5 includes the following steps:

[0448] The negative electrode sheet comprises a negative electrode current collector and a negative electrode film layer, the negative electrode film layer is located on both sides of the negative electrode current collector, the negative electrode current collector is a copper foil, the negative electrode film layer is a film layer formed by uniformly coating a negative electrode slurry (the solvent is deionized water) on the surface of the negative electrode current collector copper foil, drying and cold pressing, the negative electrode film layer comprises a silicon-based material (specifically, a silicon oxide compound), graphite, a conductive agent carbon black, a conductive agent carbon nanotube and a binder polyacrylic acid; and the mass content of the silicon element and the capacity area density are adjusted.

[0449] Embodiments 6-9

[0450] The battery monomer is prepared by using a method similar to that of Embodiment 1, and different from Embodiment 1, the thickness of the side wall is adjusted in Embodiments 6-9.

[0451] The test results of each embodiment are shown in Table 1.

[0452] Table 1

[0453] Referring to Table 1, the energy density of the cylindrical battery monomer can be significantly improved by introducing silicon into the negative electrode active material. By providing organic particles on the separator, a gap can be formed between the positive electrode sheet and the negative electrode sheet, which can provide space for the expansion of the negative electrode sheet. Referring to Table 1, the expansion volume of the cylindrical battery monomer is less than or equal to 0.5 mL, the cycle number of the cylindrical battery monomer is greater than or equal to 800, and the cylindrical battery monomer has good reliability and cycle performance.

[0454] Referring to Embodiments 1-5, by adjusting the mass content of the silicon element, the capacity area density can be adjusted synchronously, which is beneficial to improving the cycle performance and energy density of the battery monomer. The gap can provide space for the expansion of the negative electrode sheet, and when the content of the silicon element reaches 19%, the expansion volume of the cylindrical battery monomer is less than or equal to 0.5 mL, and the cycle number of the cylindrical battery monomer is greater than or equal to 800.

[0455] Referring to Embodiments 1 and 6-9, by adjusting the thickness of the side wall and cooperating with the mass content of the silicon element, it is beneficial to improving the cycle performance and energy density of the battery monomer, and the volume expansion of the battery monomer is small. The mechanical strength of the steel side wall is high, which can effectively improve the volume expansion problem, and can improve the cycle performance and energy density of the battery monomer.

[0456] Although the present application has been described with reference to the preferred embodiments, various modifications can be made to it without departing from the scope of the application, and equivalent parts can be substituted for the parts thereof, especially, the technical features mentioned in each embodiment can be combined in any way as long as there is no structural conflict. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A cylindrical battery cell with a diameter ≥ 40 mm, comprising: shell; The electrode assembly is at least partially housed within the housing; The electrode assembly includes a positive electrode, a negative electrode, and a separator. The positive electrode, the negative electrode, and the separator are wound together. The separator separates the positive electrode and the negative electrode. The negative electrode active material of the negative electrode includes at least one of silicon-based material and carbon-based material. A gap is formed between the positive electrode and the negative electrode, the gap extending along the winding direction of the electrode assembly, and at least a portion of the gap having a radial dimension of 5μm-60μm.

2. The cylindrical battery cell according to claim 1, wherein, At least one of the positive electrode, the negative electrode, and the separator includes a base and a plurality of support portions disposed on the base; The base has two first surfaces arranged opposite each other along its own thickness direction, and the plurality of support portions protrude from at least one of the first surfaces to form the gap between the positive electrode and the negative electrode.

3. The cylindrical battery cell according to claim 2, wherein, The support portion is configured to be compressible.

4. The cylindrical battery cell according to claim 2 or 3, wherein, The plurality of support portions include a first support portion and a second support portion, wherein the height of the first support portion protruding from the first surface is greater than the height of the second support portion protruding from the first surface.

5. The cylindrical battery cell according to any one of claims 2-4, wherein, At least one of the positive electrode, the negative electrode, and the separator includes a plurality of organic particles, and the support portion includes the organic particles.

6. The cylindrical battery cell according to claim 5, wherein, The plurality of organic particles include a first organic particle and a second organic particle, wherein the number-average particle size of the first organic particle is greater than the number-average particle size of the second organic particle.

7. The cylindrical battery cell according to claim 5 or 6, wherein, The plurality of support portions include a first support portion and a second support portion, wherein the height of the first support portion protruding from the first surface is greater than the height of the second support portion protruding from the first surface; The plurality of organic particles include a first organic particle and a second organic particle; the first support portion includes the first organic particle, and the second support portion includes the second organic particle.

8. The cylindrical battery cell according to any one of claims 5-7, wherein, The plurality of organic particles include a first organic particle, which comprises a homopolymer or copolymer of fluorinated alkenyl monomer units, a homopolymer or copolymer of olefin monomer units, a homopolymer or copolymer of unsaturated nitrile monomer units, a homopolymer or copolymer of epoxide monomer units, and one or more of the modified compounds of the above homopolymers or copolymers. Optionally, the first organic particles include one or more of the following: polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinylidene fluoride, polyvinylidene fluoride, polyethylene, polypropylene, polyacrylonitrile, polyethylene oxide, copolymers of different fluorinated alkenyl monomer units, copolymers of fluorinated alkenyl monomer units and olefin monomer units, copolymers of fluorinated alkenyl monomer units and acrylic monomer units, copolymers of fluorinated alkenyl monomer units and acrylate monomer units, and modified compounds of the above homopolymers or copolymers.

9. The cylindrical battery cell according to any one of claims 5-8, wherein, The plurality of organic particles include a second organic particle, which includes one or more of the following: a homopolymer or copolymer of acrylate monomer units, a homopolymer or copolymer of acrylate monomer units, a homopolymer or copolymer of styrene monomer units, a polyurethane compound, a rubber compound, and a modified compound of the above homopolymers or copolymers. Optionally, the second organic particle comprises one or more of the following: a copolymer of acrylate monomer units and styrene monomer units, a copolymer of acrylate monomer units and styrene monomer units, a copolymer of acrylate monomer units-acrylate monomer units-styrene monomer units, a copolymer of styrene monomer units and unsaturated nitrile monomer units, a copolymer of styrene monomer units-olefin monomer units-unsaturated nitrile monomer units, and modified compounds of the above copolymers.

10. The cylindrical battery cell according to any one of claims 2-9, wherein, The positive electrode sheet has a plurality of support portions on the side facing the separator, and the separator has a plurality of support portions on the side facing the positive electrode sheet. The plurality of support portions of the positive electrode sheet facing the separator are at least partially opposite to the plurality of support portions of the separator facing the positive electrode sheet; and / or, The negative electrode sheet has a plurality of support portions on the side facing the insulating member, and the insulating member has a plurality of support portions on the side facing the negative electrode sheet. The plurality of support portions of the negative electrode sheet facing the insulating member are at least partially opposite to the plurality of support portions of the insulating member facing the negative electrode sheet; and / or, The negative electrode sheet has a plurality of support portions on the side facing the positive electrode sheet, and the positive electrode sheet has a plurality of support portions on the side facing the positive electrode sheet. At least a portion of the plurality of support portions of the negative electrode sheet facing the positive electrode sheet are arranged opposite to the plurality of support portions of the positive electrode sheet facing the negative electrode sheet.

11. The cylindrical battery cell according to any one of claims 2-10, wherein, The isolation member has multiple support portions on both sides; The gap includes a first gap and a second gap, the first gap being formed between the positive electrode and the separator, and the second gap being formed between the negative electrode and the separator.

12. The cylindrical battery cell according to any one of claims 2-11, wherein, The separator includes the base and a plurality of the support portions, the support portions including organic particles disposed on the base.

13. The cylindrical battery cell according to claim 12, wherein, The base of the separator includes a base film and an inorganic particle layer disposed on the base film, wherein the organic particles at least partially protrude from the inorganic particle layer.

14. The cylindrical battery cell according to any one of claims 1-13, wherein, The housing includes sidewalls surrounding the electrode assembly, the sidewalls being made of steel; The thickness of the sidewall is 0.3 mm to 1.5 mm, and optionally 0.3 mm to 1.2 mm.

15. The cylindrical battery cell according to any one of claims 1-14, wherein, The negative electrode sheet includes a negative electrode current collector and a negative electrode film layer disposed on at least one side of the negative electrode current collector and containing the negative electrode active material, wherein the negative electrode active material includes a silicon-based material; The silicon content of the silicon-based material in the negative electrode film layer is 2% to 19% by mass, and can be selected as 6% to 13%.

16. The cylindrical battery cell according to any one of claims 1-15, wherein, The negative electrode has a capacity areal density greater than or equal to 3.2 mAh / cm³. 2 .

17. The cylindrical battery cell according to claim 16, wherein, The areal density of the negative electrode is 3.3 mAh / cm³. 2 Up to 11.5mAh / cm 2 .

18. The cylindrical battery cell according to claim 17, wherein, The areal density of the negative electrode is 3.96 mAh / cm³. 2 Up to 7.56mAh / cm 2 .

19. The cylindrical battery cell according to any one of claims 1-18, wherein, The gap has a winding start end and a winding end end; The radial dimension of the portion of the gap near the starting end of winding is greater than or equal to the radial dimension of the portion of the gap near the ending end of winding.

20. The cylindrical battery cell according to any one of claims 1-19, wherein, The radial dimension of at least a portion of the gap gradually decreases along the winding direction.

21. The cylindrical battery cell according to any one of claims 1-20, wherein, The gap includes a central region and two end regions arranged along the axial direction of the cylindrical battery cell, the central region being located between the two end regions, and the radial dimension of the central region being smaller than the radial dimension of the end regions.

22. The cylindrical battery cell according to claim 21, wherein, The radial dimension of the gap gradually decreases in the direction from the end region to the middle region.

23. The cylindrical battery cell according to any one of claims 1-22, wherein, One of the positive electrode and the negative electrode includes a first tab, and the other includes a second tab; The cylindrical battery cell includes a first electrode lead-out portion and a second electrode lead-out portion, wherein the first electrode lead-out portion is electrically connected to the first electrode tab, and the second electrode lead-out portion is electrically connected to the second electrode tab; Along the axial direction of the cylindrical battery cell, the first electrode lead and the second electrode lead are located on the same side of the electrode assembly.

24. The cylindrical battery cell according to any one of claims 1-23, wherein, The housing includes a shell and an end cap. The shell includes an integrally formed sidewall and an end wall. The sidewall surrounds the electrode assembly. The end wall and the end cap are axially opposite each other along the cylindrical battery cell. The end cap is sealed to the sidewall.

25. The cylindrical battery cell according to claim 24, wherein, One of the positive electrode and the negative electrode includes a first tab, and the other includes a second tab; The cylindrical battery cell also includes an electrode terminal insulated from the end wall, wherein one of the first tab and the second tab is electrically connected to the electrode terminal and the other is electrically connected to the end wall.

26. The cylindrical battery cell according to claim 25 further includes a first current collector, the first current collector being located on the side of the first tab facing the end wall and connected to the first tab; The electrode terminal abuts against and connects to the surface of the first current collector facing the end wall.

27. The cylindrical battery cell according to claim 26, wherein, The electrode terminal has a terminal recess on the side facing the first current collector, and / or the electrode terminal has a terminal recess on the side away from the first current collector; The bottom wall of the terminal recess is welded to the first current collector.

28. The cylindrical battery cell according to any one of claims 25-27, wherein, Both the first tab and the second tab are located at the end of the electrode assembly facing the end wall.

29. The cylindrical battery cell according to any one of claims 25-27, wherein, The first electrode tab is located at the end of the electrode assembly facing the end wall, and the second electrode tab is located at the end of the electrode assembly facing the end cap; The cylindrical battery cell further includes a second current collector connected to the second tab; the second current collector is connected to at least one of the end cap and the side wall.

30. The cylindrical battery cell according to any one of claims 1-29, wherein, The height of the outer casing is 1.3 to 4 times the diameter of the outer casing.

31. The cylindrical battery cell according to any one of claims 1-30, wherein, The height of the outer casing is 50mm to 150mm; and / or The diameter of the outer casing is 45mm to 80mm.

32. A battery comprising a plurality of cylindrical battery cells according to any one of claims 1-31.

33. An electrical device comprising the battery according to claim 32, the battery being used to provide electrical energy.

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