Cylindrical battery cells, batteries, and electrical devices

Abstract

Embodiments of the present application provide a cylindrical battery cell, a battery, and an electric device. The cylindrical battery cell comprises a housing and an electrode assembly. The diameter of the cylindrical battery cell is 40 mm or more. At least a portion of the electrode assembly is accommodated within the housing. The electrode assembly comprises a positive electrode, a negative electrode, and a separator, wherein the positive electrode, the negative electrode, and the separator are installed to be wound, and the separator separates the positive electrode and the negative electrode. The negative active material of the negative electrode comprises at least one of a silicon element and a carbon element. At least one of the positive electrode, the negative electrode, and the separator comprises a base portion and a plurality of support portions installed on the base portion. The base portion has two first surfaces installed oppositely along its own thickness direction. The plurality of support portions are installed to protrude from at least one first surface to form a gap between the positive electrode and the negative electrode.

Description

Technology Field

[0001] This application relates to the field of battery technology, and more specifically to cylindrical battery cells, batteries, and electric devices.

[0002] Cross-reference regarding related applications

[0003] The present application claims priority to international patent application PCT / CN2024 / 100930, filed on June 24, 2024, titled “Cylindrical battery cell, battery and electric device,” the entire contents of said application are incorporated herein by reference. Background Technology

[0004] Battery cells, particularly cylindrical battery cells, are widely used in electronic devices such as mobile phones, laptops, electric bicycles, electric vehicles, electric airplanes, electric ships, electric toy cars, electric toy ships, electric toy airplanes, and power tools.

[0005] As the demand for energy density increases, the diameter of cylindrical battery cells is becoming larger. However, as the diameter of cylindrical battery cells increases, the expansion force of the cylindrical battery cells during the circulation process also increases, and this expansion force affects the circulation performance of the cylindrical battery cells. How to improve the circulation performance of large-diameter cylindrical battery cells is an important research direction in the field of battery technology.

[0006] The present application provides a cylindrical battery cell, a battery, and an electric device capable of improving reliability.

[0007] In a first aspect, an embodiment of the present application provides a cylindrical battery cell having a diameter of ≥40 mm, which comprises a housing and an electrode assembly. At least a portion of the electrode assembly is accommodated within the housing. The electrode assembly comprises a positive electrode, a negative electrode, and a separator, wherein the positive electrode, the negative electrode, and the separator are installed to be wound, and the separator separates the positive electrode and the negative electrode. The negative active material of the negative electrode comprises at least one of a silicon-based material and a carbon-based material. At least one of the positive electrode, the negative electrode, and the separator comprises a base portion and a plurality of support portions installed on the base portion. The base portion has two first surfaces installed oppositely along its thickness direction. The plurality of support portions are installed to protrude from at least one first surface to form a gap between the positive electrode and the negative electrode.

[0008] By installing a plurality of protruding support members, this supports at least one of the positive electrode and the negative electrode, thereby forming a gap between the positive electrode and the negative electrode; during the circulation process of the cylindrical battery cell, the gap provides space for the expansion of the negative electrode, thereby relieving the compression received by the electrolyte in the internal voids of the positive film layer of the positive electrode and the internal voids of the negative film layer of the negative electrode, reducing the difference in electrolyte concentration in each region inside the electrode, and improving the circulation performance of the cylindrical battery cell having a relatively large diameter. The gap can reduce the expansion amount of the electrode assembly, thereby reducing the compression action received by the housing and lowering the risk of the housing being deformed or cracked, which can improve the reliability of the cylindrical battery cell. By installing the gap, the amplification of the expansion force due to the increase in the diameter of the cylindrical battery cell can be reduced, and the capacity of the cylindrical battery cell can be improved by increasing the diameter of the cylindrical battery cell.

[0009] In some embodiments, the support is configured to be compressible. During the circulation process of the cylindrical battery cell, the support can be compressed when subjected to pressure, thereby providing more expansion space for the negative electrode. By releasing stress through compression and deformation, the compressible support can improve reliability by reducing the risk of the positive or negative electrode being crushed by the support.

[0010] In some embodiments, a plurality of support members include a first support member and a second support member, and on the same side of the base member, the height of the first support member protruding from the first surface is greater than the height of the second support member protruding from the first surface.

[0011] The first support member has a relatively large height, which supports the positive or negative electrode and can form a relatively large gap, thereby providing more space for the expansion of the negative electrode. The second support member has a relatively small height, so the space it occupies is also relatively small. As the negative electrode expands, the gap gradually shrinks; and since the second support member can receive pressure only after the negative electrode has expanded to a certain extent, it can reduce the pressure received by the negative electrode during the initial expansion. When the second support member receives pressure, it can relieve the expansion of the negative electrode to some extent and reduce the electrolyte extruded by the negative electrode, thereby improving the circulation performance of the cylindrical battery cell.

[0012] In some embodiments, at least one of the positive electrode, the negative electrode, and the separator comprises a plurality of organic particles, and the support comprises organic particles. The organic particles act as a support and can form a gap. When thermal runaway occurs in a cylindrical battery cell, the organic particles can form a gel film structure at high temperatures, thereby reducing the diffusion pathway of active ions and delaying the thermal diffusion time, which can improve the reliability of the cylindrical battery cell.

[0013] In some embodiments, a plurality of organic particles include a first organic particle and a second organic particle, and the number average particle size of the first organic particle is larger than the number average particle size of the second organic particle. The first organic particle, which has a relatively large number average particle size, supports the positive or negative electrode and can form a relatively large gap, thereby providing more space for the expansion of the negative electrode. The second organic particle, which has a relatively small number average particle size, can be subjected to pressure only after the negative electrode has expanded to some extent, thus reducing the pressure on the negative electrode during the initial expansion. When the second organic particle is subjected to pressure, the second organic particle can alleviate the expansion of the negative electrode to some extent and reduce the electrolyte extruded by the negative electrode, thereby improving the circulation performance of the cylindrical battery cell.

[0014] In some embodiments, a plurality of supports includes a first support and a second support, and on the same side of the base, the height of the first support protruding from the first surface is greater than the height of the second support protruding from the first surface. A plurality of organic particles include a first organic particle and a second organic particle; the first support includes the first organic particle, and the second support includes the second organic particle.

[0015] By installing first organic particles and second organic particles with different number-average particle sizes, first and second support members with different heights can be formed. The first support member has a relatively large height, which supports the positive or negative electrode and can form a relatively large gap, thereby providing more space for the expansion of the negative electrode. The second support member can receive pressure only after the negative electrode has expanded to a certain extent, thus reducing the pressure received by the negative electrode during the initial expansion. When the second support member receives pressure, the second support member can relieve the expansion of the negative electrode to some extent and reduce the electrolyte extruded by the negative electrode, thereby improving the circulation performance of the cylindrical battery cell.

[0016] In some embodiments, a plurality of organic particles comprises a first organic particle, and the first organic particle comprises one or more of a homopolymer or copolymer of fluorine-containing 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 alkylene oxide monomer units, and a modified compound of each of the above-described homopolymer or copolymer.

[0017] In some embodiments, the first organic particle comprises one or more of polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinyl fluoride, polyvinylidene fluoride, polyethylene, polypropylene, polyacrylonitrile, polyethylene oxide, copolymers of different fluorine-containing alkenyl monomer units, copolymers of fluorine-containing alkenyl monomer units and olefin monomer units, copolymers of fluorine-containing alkenyl monomer units and acrylic acid monomer units, copolymers of fluorine-containing alkenyl monomer units and acrylate monomer units, and modification compounds of each of the above-described homopolymers or copolymers.

[0018] In some embodiments, a plurality of organic particles include a second organic particle, and the second organic particle includes one or more of an acrylate-based monomer unit homopolymer or copolymer, an acrylic acid-based monomer unit homopolymer or copolymer, a styrene-based monomer unit homopolymer or copolymer, a polyurethane-based compound, a rubber-based compound, and a modified compound of each of the above-mentioned homopolymers or copolymers.

[0019] In some embodiments, the second organic particle comprises one or more of a copolymer of an acrylate monomer unit and a styrene monomer unit, a copolymer of an acrylic acid monomer unit and a styrene monomer unit, a copolymer of an acrylic acid 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 the copolymers described above.

[0020] In some embodiments, the housing includes a side wall installed to surround the electrode assembly, the thickness of the side wall is 0.3 mm to 1.5 mm, and the material of the side wall includes steel. The present application can reduce the expansion force of the electrode assembly applied to the side wall by installing a gap, and accordingly, the side wall made of steel can have a thickness of 1.5 mm or less, thereby improving the energy density of the cylindrical battery cell. The thickness of the side wall made of steel is 0.3 mm or more, which lowers the risk of the side wall being deformed or ruptured by the expansion force of the electrode assembly, thereby improving the reliability of the cylindrical battery cell.

[0021] In some embodiments, the thickness of the sidewall is 0.3mm to 1.2mm, optionally 0.3mm to 0.9mm, and more optionally 0.3mm to 0.6mm.

[0022] In some embodiments, the cathode piece comprises a cathode current collector and a cathode film layer installed on at least one side of the cathode current collector and comprising a cathode active material. The cathode active material comprises a silicon-based material, and the mass content of silicon elements of the silicon-based material in the cathode film layer is 2% to 19%.

[0023] The introduction of silicon-based materials can improve the capacity of the negative electrode active material, thereby improving the energy density of the cylindrical battery cell; the gap provides space for the expansion of the negative electrode, thereby reducing the influence of the silicon-based material on the expansion force. The embodiments of the present application limit the mass content of the silicon-based material in the negative electrode film layer to within the aforementioned range, thereby balancing the expansion and capacity of the negative electrode to some extent and combining the circulation performance and energy density of the cylindrical battery cell.

[0024] In some embodiments, the mass content of silicon elements in the silicon-based material in the cathode film layer is 6% to 13%.

[0025] In some embodiments, the capacity areal density of the cathode is 3.2 mAh / cm2 or higher. The embodiments of the present application can reduce the effect of increased areal density of the cathode on expansion force by installing a gap, and accordingly, the capacity of the cathode can be improved, thereby improving the energy density of the cylindrical battery cell.

[0026] In some embodiments, the capacity areal density of the cathode is 3.3 mAh / cm2 to 11.5 mAh / cm2. The embodiments of the present application can balance the capacity and expansion of the cathode to some extent and can combine the energy density and circulation performance of a cylindrical battery cell.

[0027] In some embodiments, the capacity areal density of the negative electrode is 3.96 mAh / cm2 to 7.56 mAh / cm2, which can further combine the energy density and circulation performance of the cylindrical battery cell.

[0028] In some embodiments, two gaps are installed, and the two gaps are installed on each side of the positive plate. By installing two gaps, the amount of expansion of the electrode assembly can be further reduced, thereby reducing the compression action received by the housing and lowering the risk of the housing being deformed or cracked, which can improve the reliability of the cylindrical battery cell.

[0029] In some embodiments, the gap extends along the winding direction of the electrode assembly, and the gap has a winding start end and a winding end.

[0030] In some embodiments, the radial size of at least some gaps is 5 μm to 60 μm. By limiting the radial size W of at least some gaps to 5 μm or more, space can be provided for the expansion of the negative electrode, thereby reducing the expansion force, improving the circulation performance of the cylindrical battery cell, and lowering the risk of the housing being deformed or cracked. In the embodiments of the present application, by limiting the radial size W of at least some gaps to 60 μm or less, the ion transport path between the positive electrode and the negative electrode is shortened, and the internal resistance of the cylindrical battery cell is reduced, thereby reducing heat generation and reducing the influence of the gap on energy density.

[0031] In some embodiments, the radial size of the portion of the gap closer to the end of the winding is larger than the radial size of the portion of the gap closer to the beginning of the winding.

[0032] In the circulation process of a cylindrical battery cell, the expansion of the negative electrode gradually accumulates from the inside out along the radial direction; in the embodiment of the present application, the portion closer to the end of the winding in the gap has a larger radial size, thereby providing more expansion space for the negative electrode, absorbing the accumulated expansion of the negative electrode, further reducing the force acting between the electrode assembly and the housing, reducing the amount of deformation of the housing, and lowering the risk of the housing cracking, thereby improving reliability.

[0033] In some embodiments, the gap is wound along the winding direction to form n winding turns, n≥20, and n is a natural number. The innermost winding turn is the first winding turn. The radial size of the k-th winding turn is smaller than the radial size of the k+10th winding turn, k is a natural number, and 5≤k≤n-15.

[0034] The k+10th winding turn is installed on the outside compared to the kth winding turn, and since the radial size of the k+10th winding turn is larger than the radial size of the kth winding turn, the k+10th winding turn provides more expansion space for the cathode film layer of the inner cathode piece, which can absorb the accumulated expansion of the cathode piece, and furthermore, can reduce the force acting between the electrode assembly and the housing, reduce the amount of deformation of the housing, and lower the risk of the housing cracking, thereby improving reliability.

[0035] In some embodiments, the gap is wound along the winding direction to form n winding turns, where n ≥ 20 and n is a natural number. The innermost winding turn is the first winding turn. The average value of the radial size of the n-9th to n-5th winding turns is greater than the average value of the radial size of the 5th to 9th winding turns.

[0036] The portion of the gap closer to the end of the winding has a larger radial size, thereby providing more expansion space for the cathode piece, absorbing the accumulated expansion of the cathode piece, further reducing the force between the electrode assembly and the housing, reducing the deformation of the housing (20), and lowering the risk of the housing (20) cracking, thereby improving reliability.

[0037] In some embodiments, the electrode assembly includes a middle region and two end regions arranged along the axial direction of a cylindrical battery cell, the middle region is located between the two end regions; and the radial size of the portion installed in the middle region in the gap is smaller than the radial size of the portion installed in the end region in the gap. Since the gap has a relatively large radial size in the end region, it facilitates the flow of electrolyte into the gap, thereby improving the infiltration effect of the electrolyte onto the electrode piece and improving the circulation performance of the cylindrical battery cell.

[0038] In some embodiments, as the two end regions each face the middle region, the radial size of the gap shows a decreasing trend, thereby reducing the abrupt change in the radial size of the gap and reducing stress concentration in the negative electrode, thereby improving the circulation performance of the battery cell.

[0039] In some embodiments, the separating member comprises a base portion and a plurality of support portions, and the support portions comprise organic particles installed on the base portion. The organic particles support the anode or cathode portion, thereby increasing the gap and providing space for the expansion of the cathode portion.

[0040] In some embodiments, the base portion of the separating member comprises a base membrane and an inorganic particle layer installed on the base membrane, and organic particles protrude at least partially from the inorganic particle layer. The inorganic particle layer comprises a plurality of inorganic particles, and a sufficiently non-uniformly distributed gap is formed between the inorganic particles and the organic particles, thereby improving the air permeability of the separating member so that the cylindrical battery cell can have relatively excellent circulation performance and reliability.

[0041] In some embodiments, a plurality of support members are installed on one side of the positive member facing the separating member, and a plurality of support members are installed on one side of the separating member facing the positive member, and the plurality of support members of the positive member facing the separating member are installed at least partially opposite to the plurality of support members of the separating member facing the positive member. By installing the plurality of support members of the positive member facing the plurality of support members of the separating member, the plurality of support members of the positive member and the plurality of support members of the separating member are made to come into at least partial contact, thereby increasing the gap and providing more space for the expansion of the negative member.

[0042] In some embodiments, a plurality of support members are installed on one side of a cathode piece facing a separating member, and a plurality of support members are installed on one side of a separating member facing a cathode piece, and the plurality of support members of the cathode piece facing the separating member are installed at least partially opposite to the plurality of support members of the separating member facing the cathode piece. By installing the plurality of support members of the cathode piece facing the plurality of support members of the separating member, the support members of the cathode piece and the support members of the separating member are made to come into at least partial contact, thereby increasing the gap and providing more space for the expansion of the cathode piece.

[0043] In some embodiments, a plurality of support members are installed on one side of a cathode member facing an anode member, and a plurality of support members are installed on one side of an anode member facing a cathode member, and the plurality of support members of the cathode member facing anode member are installed facing at least a portion of the plurality of support members of the anode member facing a cathode member. By installing the plurality of support members of the cathode member facing the plurality of support members of the anode member, the support members of the cathode member and the support members of the anode member are supported by each other, thereby increasing the gap and providing more space for the expansion of the cathode member.

[0044] In some embodiments, a plurality of support members are installed on both sides of the separating member. By installing a plurality of support members on both sides of the separating member, the gap can be increased and more space can be provided for the expansion of the cathode piece.

[0045] In some embodiments, the gap includes a first gap and a second gap, the first gap is formed between the positive electrode and the separating member, and the second gap is formed between the negative electrode and the separating member. Both the first gap and the second gap can provide space for the expansion of the negative film layer, thereby reducing the compressive action received by the housing and lowering the risk of the housing being deformed or cracked, which can improve the reliability of the cylindrical battery cell.

[0046] In some embodiments, an anode recess is installed on one side of the anode piece facing the separating member.

[0047] By installing a positive recess, the gap between the positive plate and the negative plate can be increased; during the circulation process of the cylindrical battery cell, the positive recess provides space for the expansion of the negative film layer, thereby reducing the pressure between the positive plate and the negative plate. Consequently, the compression received by the electrolyte in the internal voids of the positive film layer and the negative film layer can be alleviated, the difference in electrolyte concentration in each region within the electrode plate can be reduced, and the circulation performance of the cylindrical battery cell having a relatively large diameter can be improved. The positive recess reduces the expansion amount of the electrode assembly, thereby reducing the compression action received by the housing and lowering the risk of the housing being deformed or cracked, which can improve the reliability of the cylindrical battery cell.

[0048] In some embodiments, the anode piece includes an anode film layer, and since the anode concave portion is formed in the anode film layer, the influence of the anode concave portion on the current flow capability of the anode current collector of the anode piece can be reduced.

[0049] In some embodiments, the positive recess penetrates the positive film layer along the axial direction of the cylindrical battery cell, increasing the gap between the positive and negative electrodes and improving the infiltration of the electrolyte.

[0050] In some embodiments, the anode recesses are plurality; and at least some of the plurality of anode recesses are installed on the inner side of the anode piece. Since the curvature of the inner side of the anode piece is relatively large, by installing the anode recesses on the inner side of the anode piece, stress is released, thereby reducing the risk of the anode active material in the anode film layer detaching.

[0051] In some embodiments, the anode piece includes a plurality of anode recesses spaced apart along the winding direction. The plurality of anode recesses provide space for expansion in different regions of the cathode film layer, thereby reducing the pressure between the anode piece and the cathode piece.

[0052] In some embodiments, a cathode recess is installed on one side of the cathode piece facing the separating member.

[0053] By installing a negative electrode recess, the gap between the positive electrode and the negative electrode can be increased; during the circulation process of the cylindrical battery cell, the negative electrode recess provides space for the expansion of the negative electrode film layer, thereby reducing the pressure between the positive electrode and the negative electrode. Consequently, the compression received by the electrolyte in the internal voids of the positive electrode film layer and the negative electrode film layer can be alleviated, the difference in electrolyte concentration in each region within the electrode can be reduced, and the circulation performance of the cylindrical battery cell having a relatively large diameter can be improved. The negative electrode recess reduces the expansion amount of the electrode assembly, thereby reducing the compression action received by the housing and lowering the risk of the housing being deformed or cracked, which can improve the reliability of the cylindrical battery cell.

[0054] In some embodiments, the cathode piece includes a cathode film layer, and the cathode concave portion is formed in the cathode film layer, so that the influence of the cathode concave portion on the current flow capability of the cathode current collector of the cathode piece can be reduced.

[0055] In some embodiments, the negative electrode recess penetrates the negative film layer along the axial direction of the cylindrical battery cell, increasing the gap between the positive electrode and the negative electrode and improving the infiltration of the electrolyte.

[0056] In some embodiments, the cathode recesses are plurality; at least some of the plurality of cathode recesses are installed on the inner side of the cathode piece. Since the curvature of the inner side of the cathode piece is relatively large, by installing the cathode recesses on the inner side of the cathode piece, stress is released, thereby reducing the risk of the cathode active material in the cathode film layer detaching.

[0057] In some embodiments, the cathode piece includes a plurality of cathode recesses spaced apart along the winding direction. The plurality of cathode recesses provide space for expansion in different regions of the cathode film layer, thereby reducing the pressure between the anode piece and the cathode piece.

[0058] In some embodiments, one of the positive electrode and the negative electrode includes a first electrode tab, and the other includes a second electrode tab. A cylindrical battery cell includes a first electrode lead and a second electrode lead, wherein the first electrode lead is electrically connected to the first electrode tab and the second electrode lead is electrically connected to the second electrode tab. In 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. When a plurality of cylindrical battery cells are grouped and assembled, the first electrode lead and the second electrode lead of the plurality of cylindrical battery cells can be arranged on the same side, thereby facilitating the connection between the busbar component and the first electrode lead and the second electrode lead, and simplifying the battery structure.

[0059] In some embodiments, the housing comprises a housing body and an end cover, the housing body comprises a side wall and an end wall, the side wall surrounds the electrode assembly, the end wall and the end cover face each other along the axial direction of the cylindrical battery cell, and the end cover is sealedly connected to the side wall.

[0060] In some embodiments, the side walls and end walls are formed integrally.

[0061] In some embodiments, one of the positive and negative electrodes includes a first electrode tab, and the other includes a second electrode tab. The cylindrical battery cell also includes an electrode terminal installed insulatedly on an end wall, and one of the first electrode tab and the second electrode 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 be used as two electrodes exposed to the outside of the cylindrical battery cell, and since the electrode terminal and the end wall are located on the same side, it is advantageous for assembling a plurality of cylindrical battery cells by grouping them, and simplifies the battery structure.

[0062] In some embodiments, the cylindrical battery cell also includes a first current collector, the first current collector is located on one side of a first electrode tab facing the end wall and is connected to the first electrode tab. An electrode terminal is connected by contacting the surface of the first current collector facing the end wall. The first current collector acts as a connection to enable an electrical connection between the first electrode tab and the electrode terminal.

[0063] In some embodiments, a terminal recess is provided on one side of an electrode terminal facing the first current collector, and / or, a terminal recess is provided on one side of an electrode terminal away from the first current collector. The lower wall of the terminal recess is welded to the first current collector. By providing the terminal recess, the thickness of the lower wall of the terminal recess can be reduced, the power required to weld the electrode terminal and the first current collector from the outside can be reduced, and the risk of particles generated by welding falling into the housing can be lowered, thereby improving the reliability of the cylindrical battery cell.

[0064] In some embodiments, the first electrode tab and the second electrode tab are both located at one end of the electrode assembly facing the end wall. The first electrode tab and the second electrode tab may share space in the axial direction, thereby improving space utilization and energy density.

[0065] In some embodiments, a first electrode tab is located at one end of an electrode assembly facing an end wall, and a second electrode tab is located at one end of an electrode assembly facing an end cover. The cylindrical battery cell also includes a second current collector connected to the second electrode tab; the second current collector is connected to at least one of the end cover and the side wall.

[0066] In some embodiments, the height of the housing is 1.3 to 4 times the diameter of the housing. If the housing meets the size requirements described above, the structural stability of the housing is improved, which can improve the reliability of use of the cylindrical battery cell.

[0067] In some embodiments, the height of the housing is 50 mm to 150 mm.

[0068] In some embodiments, the diameter of the housing is 45 mm to 80 mm.

[0069] In a second aspect, an embodiment of the present application provides a battery comprising a cylindrical battery cell provided in any one embodiment of a plurality of first aspects.

[0070] In a third aspect, an embodiment of the present application provides an electric device comprising a battery provided in any one embodiment of the second aspect, and the battery is used to provide electric energy. Brief explanation of the drawing

[0071] In order to explain the technical method of the embodiments of the present application more clearly, we will briefly introduce the drawings necessary for describing the embodiments of the present application below. The drawings described below are merely some embodiments of the present application, and it is obvious to those skilled in the art that other drawings can be obtained based on these drawings without requiring creative labor. FIG. 1 is a structural schematic diagram of a vehicle provided in some embodiments of the present application; FIG. 2 is an exploded schematic diagram of a battery provided in some embodiments of the present application; FIG. 3 is a structural schematic diagram of the battery module shown in FIG. 2; FIG. 4 is a structural schematic diagram of a cylindrical battery cell according to some embodiments of the present application; FIG. 5 is an exploded schematic diagram of a cylindrical battery cell shown in FIG. 4; FIG. 6 is a schematic cross-sectional view of an electrode assembly of a cylindrical battery cell provided in some embodiments of the present application; FIG. 7 is an enlarged schematic diagram of position A indicated by the dotted frame of FIG. 6; FIG. 8 is a schematic diagram of a separating member of an electrode assembly of a cylindrical battery cell provided in some embodiments of the present application; FIG. 9 is a partial schematic cross-sectional view of an electrode assembly of a cylindrical battery cell provided in some other embodiments of the present application; FIG. 10 is a schematic diagram of a separating member of an electrode assembly of a cylindrical battery cell provided in some other embodiments of the present application; FIG. 11 is a partial schematic cross-sectional view of an electrode assembly of a cylindrical battery cell provided in some embodiments of the present application; FIG. 12 is a schematic diagram of a positive plate of an electrode assembly provided in some embodiments of the present application, unfolded flat; FIG. 13 is a schematic cross-sectional view of the positive plate of an electrode assembly provided in some embodiments of the present application; FIG. 14 is a schematic cross-sectional view of a cathode piece of an electrode assembly provided in some embodiments of the present application; FIG. 15 is a schematic cross-sectional view of an anode provided in some other embodiments of the present application; FIG. 16 is a schematic cross-sectional view of a cathode provided in some other embodiments of the present application; FIG. 17 is a partial cross-sectional view of an electrode assembly of a cylindrical battery cell provided in some other embodiments of the present application; FIG. 18 is a partial cross-sectional view of an electrode assembly of a cylindrical battery cell provided in some other embodiments of the present application; FIG. 19 is a partial cross-sectional view of an electrode assembly of a cylindrical battery cell provided in another embodiment of the present application; FIG. 20 is a schematic diagram of the positive plate of a cylindrical battery cell in an expanded state provided in some other embodiments of the present application; FIG. 21 is a schematic diagram of the negative electrode portion of a cylindrical battery cell in an unfolded state provided in some other embodiments of the present application; FIG. 22 is a schematic cross-sectional view of the battery cell illustrated in FIG. 4; FIG. 23 is a schematic diagram of the dotted circle location in FIG. 22 enlarged; FIG. 24 is a partial schematic cross-sectional view of a battery cell provided in another embodiment of the present application; FIG. 25 is a partial schematic cross-sectional view of a cylindrical battery cell provided in some other embodiments of the present application. In the drawing, the drawing was not plotted at the ratio of the actual size. Specific details for implementing the invention

[0072] In order to provide a clearer understanding of the purpose, technical solution, and advantages of the embodiments of the present application, the technical solution according to the embodiments of the present application will be clearly explained below in conjunction with the drawings of the embodiments of the present application. It will be obvious that the embodiments described are only some embodiments of the present application, not all embodiments. All other embodiments obtained by a person skilled in the art without creative labor based on the embodiments of the present application fall within the scope of protection of the present application.

[0073] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by those skilled in the art of this application; terms used in the specification of this application are used merely for the purpose of describing specific embodiments; and are not intended to limit this application; and any variations of the terms “include” and “have” used in the specification, claims, and description of the drawings above are intended to encompass non-exclusive inclusion. Terms such as “first,” “second,” etc. in the specification, claims, or drawings above are used to distinguish different objects, not to describe a specific order or master-slave relationship.

[0074] The term "Examples" as used in this application means that specific features, structures, or characteristics described by combining examples may be included in at least one of the embodiments of this application. The words appearing in various places in this specification do not necessarily refer to the same embodiment, nor are they independent embodiments or alternative embodiments mutually exclusive from other embodiments.

[0075] In describing this application, unless otherwise clearly defined and limited, the terms “mounting,” “connecting to,” “connection,” and “attachment” are to be understood in a broad sense and may, for example, be a fixed connection, a detachable connection, or an integral connection; may be a direct connection, an indirect connection through an intermediate medium, or an internal connection between two elements. Those skilled in the art will understand the specific meaning of the aforementioned terms in this application according to the specific circumstances.

[0076] In this application, the term "and / or" merely describes an association describing related objects and indicates that three relationships may exist; for example, A and / or B may represent three cases: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, in this application, the symbol " / " generally indicates that the preceding and succeeding related objects are in an "or" relationship.

[0077] In the embodiments of this application, the same drawing symbols denote the same parts, and for brevity, detailed descriptions of the same parts in other embodiments are omitted. It should be understood that the dimensions, such as thickness, length, and width, of the various parts of the embodiments of this application illustrated in the drawings, and the dimensions, such as the overall thickness, length, and width, of the integrated device, are merely illustrative and should not constitute any limitation to this application.

[0078] The term "plural" as used in this application refers to two or more (including two).

[0079] A cylindrical battery cell can be a cylindrical secondary battery, and a secondary battery refers to a battery cell that can be continuously used by activating the active material through a charging method after discharge.

[0080] A battery refers to a single physical module containing one or more cylindrical battery cells to provide higher voltage and capacity.

[0081] A cylindrical battery cell typically includes an electrode assembly and a housing used to accommodate the electrode assembly. The electrode assembly typically includes a positive electrode, a negative electrode, and a separator, and the separator separates the positive electrode and the negative electrode.

[0082] During the charge-discharge cycle of a cylindrical battery cell, the negative electrode expands due to the insertion of ions; as the diameter of the cylindrical battery cell increases, the amount of expansion of the negative electrode accumulates, which can generate a greater expansion force. Consequently, the pressure between the positive and negative electrodes increases, causing the electrolyte within the internal voids of the positive film layer of the positive electrode and the electrolyte within the internal voids of the negative film layer of the negative electrode to be extruded, thereby affecting the circulation performance of the cylindrical battery cell.

[0083] In addition, the expanded electrode assembly can also compress the housing, causing deformation or even rupture of the housing, which affects the reliability of the cylindrical battery cell.

[0084] In light of this, the embodiment of the present application provides a technical solution that can reduce expansion force, improve the circulation performance of a cylindrical battery cell, and improve the reliability of a cylindrical battery cell by installing a plurality of support members on at least one of a positive electrode, a negative electrode, and a separating member, thereby forming a gap between the positive electrode and the negative electrode, and the gap can provide space for the expansion of the negative electrode.

[0085] The cylindrical battery cell described in the embodiments of the present application is applied to a battery and an electric device using the battery.

[0086] The electric device disclosed in the embodiments of the present application may be a device that uses a battery as a power source or various energy storage systems that use a battery as an energy storage element. The electric device may be, but is not limited to, a mobile phone, tablet, laptop, electric toy, power tool, electric bicycle, electric vehicle, ship, space equipment, etc. Here, electric toys may include stationary or mobile electric toys such as, for example, game consoles, electric vehicle toys, electric ship toys, and electric airplane toys, and space equipment may include airplanes, rockets, space shuttles, and spacecraft.

[0087] In the following examples, for the convenience of explanation, the case where the electric device is a vehicle is used as an example.

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

[0089] As illustrated in FIG. 1, a battery (2) is installed inside the vehicle (1), and the battery (2) may be installed in the bottom, head, or tail portion of the vehicle (1). The battery (2) may be used to supply power to the vehicle (1), and, for example, the battery (2) may be used as the working power source for the vehicle (1).

[0090] The vehicle (1) may also include a controller (3) and a motor (4), and the controller (3) is used to control the battery (2) to supply power to the motor (4), for example, to supply the working power required for the operation, navigation, and driving of the vehicle (1).

[0091] In some embodiments of the present application, the battery (2) may be used as a working power source for the vehicle (1), as well as as a driving power source for the vehicle (1), and may provide driving power to the vehicle (1) by replacing or partially replacing fuel or natural gas.

[0092] FIG. 2 is an exploded schematic diagram of a battery provided in some embodiments of the present application. As shown in FIG. 2, the battery (2) includes a case (5) and a cylindrical battery cell (not shown in FIG. 2), and the cylindrical battery cell is accommodated within the case (5).

[0093] A case (5) is used to accommodate a cylindrical battery cell, and the case (5) may have various structures. In some embodiments, the case (5) may include a first case portion (5a) and a second case portion (5b), and the first case portion (5a) and the second case portion (5b) are covered and joined together, and the first case portion (5a) and the second case portion (5b) jointly form a limited receiving space (5c) used to accommodate a cylindrical battery cell. The second case portion (5b) is a hollow structure with one end open, and the first case portion (5a) is a plate-shaped structure, and the first case portion (5a) is covered and joined to the opening side of the second case portion (5b) to form a case (5) having a receiving space (5c); The first case part (5a) and the second case part (5b) may both be hollow structures with one side open, and the open side of the first case part (5a) may be covered and joined to the open side of the second case part (5b) to form a case (5) having a receiving space (5c). Of course, the first case part (5a) and the second case part (5b) may have various shapes, such as a cylindrical shape or a rectangular shape.

[0094] To improve the sealing performance after connecting the first case part (5a) and the second case part (5b), a sealing member such as a sealant or a sealing ring may be installed between the first case part (5a) and the second case part (5b).

[0095] Assuming that the first case part (5a) is fitted onto the upper part of the second case part (5b) and combined, the first case part (5a) can be referred to as the upper case cover and the second case part (5b) can be referred to as the lower case.

[0096] In the battery (2), there may be one cylindrical battery cell or multiple cylindrical battery cells. When there are multiple cylindrical battery cells, the multiple cylindrical battery cells may be connected in series, parallel, or a combination of series and parallel, and a combination of series and parallel connection indicates that there are both series and parallel connections among the multiple cylindrical battery cells. After directly connecting multiple cylindrical battery cells in series, parallel, or a combination of series and parallel, an integrated body composed of multiple cylindrical battery cells can be housed in a case (5); of course, multiple cylindrical battery cells may first be connected in series, parallel, or a combination of series and parallel to form a battery module (6), and then multiple battery modules (6) may be connected again in series, parallel, or a combination of series and parallel to form a single integrated body, which can then be housed in a case (5).

[0097] Cylindrical battery cells can be the smallest unit that makes up a battery.

[0098] In some embodiments, the case (5) may include a top cover, a frame, and a bottom plate. The top cover and the bottom plate are each connected to the frame to form a closed space within the case capable of accommodating a battery cell assembly. For example, the frame may include a plurality of beams.

[0099] In some embodiments, the case (5) may be used as part of the chassis structure of a vehicle. For example, a part of the case (5) may be at least part of the vehicle floor, or a part of the case (5) may be at least part of the transverse beam and longitudinal beam of the vehicle.

[0100] In some embodiments, the battery (2) may be an energy storage device.

[0101] Energy storage devices can be used in energy storage power plants, wind power systems, solar power systems, mobile power systems, or temporary power supply systems. Energy storage devices can store electrical energy according to demand and output electrical energy at appropriate times. For example, energy storage devices can store electrical energy during periods of low power demand and provide it to relevant users or electrical devices during periods of high power demand.

[0102] Energy storage devices include energy storage containers, energy storage cabinets, etc.

[0103] Figure 3 is a structural schematic diagram of the battery module shown in Figure 2.

[0104] In some embodiments, as shown in FIG. 3, the cylindrical battery cells (7) are multiple, and the multiple cylindrical battery cells (7) are first connected in series, parallel, or a combination of series and parallel to form a battery module (6). The multiple battery modules (6) are connected in series, parallel, or a combination of series and parallel to form a single integrated unit and are housed in a case.

[0105] Multiple cylindrical battery cells (7) in a battery module (6) are electrically connected by a busbar component, thereby enabling series, parallel, or mixed series-parallel connection of multiple cylindrical battery cells (7) in the battery module (6). There may be one or more busbar components, and each busbar component is used to electrically connect at least two cylindrical battery cells (7).

[0106] The cylindrical battery cell (7) may 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.

[0107] FIG. 4 is a structural schematic diagram of a cylindrical battery cell according to some embodiment of the present application; FIG. 5 is an exploded schematic diagram of the cylindrical battery cell shown in FIG. 4; FIG. 6 is a schematic cross-sectional view of an electrode assembly of a cylindrical battery cell provided in some embodiment of the present application; FIG. 7 is an enlarged schematic diagram of position A indicated by the dotted frame of FIG. 6; and FIG. 8 is a schematic diagram of a separating member of an electrode assembly of a cylindrical battery cell provided in some embodiment of the present application.

[0108] Referring to FIGS. 4 through 8, an embodiment of the present application provides a cylindrical battery cell (7) comprising a housing (20) and an electrode assembly (10), wherein at least a portion of the electrode assembly (10) is accommodated within the housing (20).

[0109] The housing (20) has a hollow structure and a receiving space is formed inside to accommodate the electrode assembly (10) and the electrolyte. The housing (20) of the cylindrical battery cell (7) is a cylindrical housing.

[0110] For example, the housing (20) includes a housing body (21) and an end cover (22), the housing body (21) has an opening, and the end cover (22) is used to be placed over the opening and joined.

[0111] The housing body (21) is a part used to form an internal hollow of a cylindrical battery cell (7) by fitting with an end cover (22), and the formed internal hollow can be used to accommodate an electrode assembly (10), an electrolyte, and other parts.

[0112] The housing body (21) and the end cover (22) may be independent parts. For example, an opening may be installed in the housing body (21), and the end cover (22) may be fitted over the opening at the opening position and joined, thereby forming an internal hollow portion of the cylindrical battery cell (7).

[0113] The housing body (21) can be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, etc.

[0114] The shape of the end cover (22) can be adapted to the shape of the housing body (21) and fitted to the housing body (21). The material of the end cover (22) and the material of the housing body (21) may be the same or different. Optionally, the end cover (22) may be manufactured from a material having a certain hardness and strength (e.g., copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc.), and accordingly, the end cover (22) does not easily deform when subjected to a compressive impact, allowing the cylindrical battery cell (7) to have higher structural strength and improve reliability.

[0115] The end cover (22) is connected to the housing body (21) by welding, bonding, hook connection, or other methods.

[0116] The housing body (21) may be open at one end or open at both ends. In some examples, the housing body (21) may have a structure with one side open, and the end cover (22) is installed as one and attached to the housing body (21). In other examples, the housing body (21) may have a structure with both sides open, and the end cover (22) is installed as two, and the two end covers (22) are each attached to the two openings of the housing body (21).

[0117] In some embodiments, the housing body (21) includes a side wall (212) and an end wall (211), the end wall (211) and the end cover (22) face each other along the axial direction (Z) of the cylindrical battery cell, and the end cover (22) is sealedly connected to the side wall (212).

[0118] In some embodiments, the side wall (212) and the end wall (211) are formed integrally.

[0119] The electrode assembly (10) is a component that causes an electrochemical reaction in a cylindrical battery cell (7). The electrode assembly (10) may be entirely housed within the housing (20) or partially housed within the housing (20). For example, a portion of the electrode tab of the electrode assembly (10) may extend outside the housing (20).

[0120] Optionally, the electrode assembly (10) is entirely accommodated within the housing (20).

[0121] In some embodiments, the diameter of the cylindrical battery cell is 40 mm or more. Cylindrical battery cells with a large diameter have a relatively high capacity, which is advantageous for improving energy density when assembling multiple cylindrical battery cells by grouping them together.

[0122] In some embodiments, the electrode assembly (10) includes a positive electrode (11) and a negative electrode (12). During the charging and discharging process of the cylindrical battery cell (7), active ions (e.g., lithium ions) are inserted and removed in a reciprocal manner between the positive electrode (11) and the negative electrode (12).

[0123] In some embodiments, the positive plate (11) may include a positive current collector and a positive film layer installed on at least one surface of the positive current collector.

[0124] For example, the positive current collector has two surfaces facing each other in its thickness direction, and the positive film layer is installed on any one or both of the two surfaces facing each other of the positive current collector.

[0125] For example, the positive current collector may use a metal foil or a composite current collector. For example, as a metal foil, silver-surfaced aluminum or stainless steel, stainless steel, copper, aluminum, nickel, carbon black electrode, carbon, nickel, or titanium may be used. The composite current collector may include a polymer material substrate and a metal layer. The composite current collector may be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, silver alloy, etc.) on a polymer material substrate (e.g., polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0126] For example, the positive film layer comprises a positive active material, and the positive active material may include at least one of materials such as a lithium-containing phosphate, a lithium transition metal oxide, and a modified compound thereof. However, the present application is not limited to these materials, and other traditional materials that can be used as battery positive active materials may also be used. Such positive active materials may be used individually or in combination of two or more. Here, examples of lithium-containing phosphates may include, but are not limited to, at least one of lithium iron phosphate (e.g., LiFePO4 (which may be abbreviated 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 lithium transition metal oxides include 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, and lithium nickel cobalt manganese oxide (e.g., LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (NCM 333It may also be abbreviated as), LiNi 0.5 Co 0.2 Mn 0.3 O2 (NCM 523 It may also be abbreviated as), LiNi 0.5 Co 0.25 Mn 0.25 O2 (NCM 211 It may also be abbreviated as ), LiNi 0.6 Co 0.2 Mn 0.2 O2 (NCM 622 It may also be abbreviated as ), LiNi 0.8 Co 0.1 Mn 0.1 O2 (NCM 811 It may also be abbreviated as ), lithium nickel cobalt aluminum oxide (e.g., LiNi 0.80 Co 0.15 Al 0.05 It may include at least one of O2) and their modified compounds, but is not limited thereto.

[0127] In some embodiments, the cathode piece (12) may include a cathode current collector and a cathode film layer installed on at least one surface of the cathode current collector.

[0128] For example, the negative current collector may use a metal foil, a metal foam, a carbon foam, or a composite current collector. For example, as a metal foil, silver-surfaced aluminum or stainless steel, stainless steel, copper, aluminum, nickel, carbon black electrode, carbon, nickel, or titanium, etc. may be used. The metal foam may be a nickel foam, a copper foam, an aluminum foam, an alloy foam, etc. The composite current collector may include a polymer material substrate and a metal layer. The composite current collector may be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver, silver alloy, etc.) on a polymer material substrate (e.g., a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0129] For example, a cathode current collector has two surfaces facing each other in its thickness direction, and a cathode film layer is installed on any one or both of the two surfaces facing each other of the cathode current collector.

[0130] For example, the negative film layer comprises a negative active material. For instance, the negative active material may include at least one of materials such as synthetic graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate. The silicon-based material may be selected from at least one of single-element silicon, silicon-oxygen compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. The tin-based material may be selected from at least one of single-element tin, tin-oxygen compounds, and tin alloys. However, the present application is not limited to these materials, and other traditional materials that can be used as battery negative active materials may also be used. These negative active materials may be used individually or in combination of two or more.

[0131] In some embodiments, the material of the positive current collector may be aluminum, and the material of the negative current collector may be copper.

[0132] In some embodiments, the electrode assembly (10) also includes a separating member (13) installed between the positive electrode (11) and the negative electrode (12). The separating member (13) can serve to prevent a short circuit between the positive and negative electrodes and simultaneously allow active ions to pass through.

[0133] In some embodiments, the cylindrical battery cell (7) may also include an electrolyte, and the electrolyte serves to conduct ions between the positive electrode (11) and the negative electrode (12). The electrolyte may be in a liquid state, a gel state, or a solid state.

[0134] In some embodiments, the liquid electrolyte comprises an electrolyte salt and a solvent.

[0135] For example, the electrolyte salt may be selected from at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluoro(oxalato)borate, lithium bis(oxalato)borate, lithium difluoro(bis-oxalato)phosphate, and lithium tetrafluoro(oxalato)phosphate.

[0136] For example, the solvent may be selected from at least one of ethylene carbonate, propylene carbonate, ethyl methyl 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, sulfolane, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone. The solvent may also be selected from an ether-based solvent. The ether-based solvent may 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, methyltetrahydrofuran, diphenyl ether, and crown ether.

[0137] In some embodiments, the gel electrolyte comprises a framework network using a polymer as the electrolyte and combines an ionic liquid-lithium salt.

[0138] In some embodiments, the solid-state electrolyte includes a polymer solid-state electrolyte, an inorganic solid-state electrolyte, and a composite solid-state electrolyte.

[0139] For example, polymer solid-state electrolytes may be polyether (polyethylene oxide), polysiloxane, polycarbonate, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, homoionic polymer, polyionic liquid-lithium salt, cellulose, etc.

[0140] For example, the inorganic solid-state electrolyte may be one or more of oxide solid-state electrolytes (crystalline perovskite, sodium superconducting ion conductor, garnet, amorphous LiPON film), sulfide solid-state electrolytes (crystalline lithium superion conductor (lithium germanium phosphorus, sulfur silver germanium ore), amorphous sulfide) and halide solid-state electrolytes, nitride solid-state electrolytes and hydride solid-state electrolytes.

[0141] For example, a composite solid-state electrolyte is formed by adding an inorganic solid-state electrolyte filler to a polymeric solid-state electrolyte.

[0142] In some embodiments, the positive electrode (11), the negative electrode (12), and the separating member (13) are installed to be wound.

[0143] The electrode assembly (10) is a wound structure. For example, the positive electrode (11), the separating member (13), and the negative electrode (12) are wound to form a cylindrical wound structure.

[0144] In some embodiments, the diameter of the cylindrical battery cell (7) is 40 mm or more. The cylindrical battery cell (7) includes a housing (20) and an electrode assembly (10), and at least a portion of the electrode assembly (10) is accommodated within the housing (20).

[0145] For example, the diameter of the housing is 40 mm or more.

[0146] The electrode assembly (10) includes an anode (11), a cathode (12), and a separating member (13), and the anode (11), cathode (12), and separating member (13) are installed to be wound, and the separating member (13) separates the anode (11) and the cathode (12).

[0147] The negative active material of the negative electrode (12) includes at least one of a silicon-based material and a carbon-based material.

[0148] At least one of the positive plate (11), the negative plate (12), and the separating member (13) comprises a base portion (15) and a plurality of support portions (14) installed on the base portion (15). The base portion (15) has two first surfaces (151) installed oppositely along its own thickness direction, and the plurality of support portions (14) are installed protruding from at least one first surface (151) to form a gap (G) between the positive plate (11) and the negative plate (12).

[0149] For example, carbon-based materials include at least one of synthetic graphite and natural graphite.

[0150] For example, silicon-based materials include at least one of single-element silicon, silicon-oxygen compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys.

[0151] For example, a plurality of support members (14) are arranged to be distributed on the first surface (151).

[0152] In some examples, a plurality of support members (14) may be installed protrudingly on one first surface (151) of the base member (15), and of course, a plurality of support members (14) may be installed protrudingly on the first surface (151) of the base member (15) facing inward along the radial direction of the cylindrical battery cell, and a plurality of support members (14) may be installed protrudingly on the first surface (151) of the base member (15) facing outward along the radial direction of the cylindrical battery cell.

[0153] In some other examples, multiple support members (14) are installed on both first surfaces (151) of the base member (15).

[0154] In the electrode assembly (10), a support member (14) may be installed on one of the positive electrode (11), the negative electrode (12), and the separating member (13), a support member (14) may be installed on both, and a support member (14) may also be installed on all three.

[0155] In some examples, the positive plate (11) includes a base portion and a plurality of support portions, and for convenience of explanation, the base portion of the positive plate (11) may be referred to as the positive base portion. Optionally, support portions may be installed on the negative plate (12) and the separating member (13), or support portions may not be installed. In the plurality of support portions of the positive plate (11), some support portions may be in contact with the separating member, and all support portions may be in contact with the separating member.

[0156] In some examples, the cathode piece (12) includes a base portion and a plurality of support portions, and for convenience of explanation, the base portion of the cathode piece may be referred to as the cathode base portion. Optionally, support portions may be installed on the anode piece (11) and the separating member (13), or support portions may not be installed. In the plurality of support portions of the cathode piece (12), some support portions may be in contact with the separating member, and all support portions may be in contact with the separating member.

[0157] In some examples, the separating member (13) includes a base portion (15) and a plurality of support portions (14), and for convenience of explanation, the base portion of the separating member (13) may be referred to as the separating base portion (131). Optionally, support portions may be installed on the positive electrode (11) and the negative electrode (12), or support portions may not be installed. For example, the positive electrode (11) may come into contact with some support portions of the separating member (13), and / or, the negative electrode (12) may come into contact with some support portions of the separating member (13).

[0158] For example, the gap (G) may be a space located between the positive electrode (11) and the negative electrode (12) and not filled by the separating member (13). Specifically, the gap (G) may be a space located between the positive film layer and the negative film layer and not filled by the separating member (13).

[0159] In some examples, a gap (G) is installed on the outer side of the positive plate (11); in other examples, a gap (G) is installed on the inner side of the positive plate (11); and in yet another example, gaps (G) are installed on both the inner and outer sides of the positive plate (11).

[0160] The support member (14) may be rigid or flexible.

[0161] In some examples, at least two of the positive electrode (11), negative electrode (12) and separating member (13) are provided with a support member (14), and the method of forming the support member (14) of both may be the same or different.

[0162] A plurality of support members (14) are installed so as to protrude, thereby supporting at least one of the positive electrode (11) and the negative electrode (12), and can form a gap (G) between the positive electrode (11) and the negative electrode (12); during the circulation process of the cylindrical battery cell (7), the gap (G) provides space for the expansion of the negative electrode (12), thereby reducing the pressure between the positive electrode (11) and the negative electrode (12), and accordingly, the compression received by the electrolyte in the internal voids of the positive film layer of the positive electrode (11) and the internal voids of the negative film layer of the negative electrode (12) can be relieved, the difference in the concentration of the electrolyte in each region inside the electrode can be reduced, and the circulation performance of the cylindrical battery cell (7) having a relatively large diameter can be improved. The gap (G) can reduce the expansion amount of the electrode assembly (10), thereby reducing the compression action received by the housing (20) and lowering the risk of the housing (20) being deformed or cracked, which can improve the reliability of the cylindrical battery cell (7). By installing the gap (G), the amplification of the expansion force due to the increase in the diameter of the cylindrical battery cell (7) can be reduced, and the diameter of the cylindrical battery cell (7) can be increased, thereby improving the capacity of the cylindrical battery cell (7).

[0163] The gap (G) can also accommodate the electrolyte, thereby improving the infiltration effect of the electrolyte on the positive and negative electrodes and improving the circulation performance of the cylindrical battery cell.

[0164] In addition, if an ion deposition problem, such as a lithium deposition problem, occurs in the negative electrode (12) during the circulation process, the gap (G) can provide space for the deformation of the separating member (13), thereby allowing the separating member (13) to release the pressure exerted by the lithium dendrite through deformation, which prevents the separating member (13) from being perforated to some extent and reduces the risk of a short circuit, thereby improving reliability.

[0165] In some embodiments, the negative electrode active material includes a carbon-based material. Since carbon-based materials have relatively high cycle stability, they can improve the cycle performance of a cylindrical battery cell.

[0166] In some embodiments, the support member (14) is configured to be compressible. During the circulation process of the cylindrical battery cell (7), the support member (14) can be compressed when subjected to pressure, thereby providing more expansion space for the negative electrode (12). The compressible support member (14) can improve reliability by releasing stress through compression and deformation, thereby reducing the risk of the positive electrode (11) or negative electrode (12) being crushed by the support member (14).

[0167] In some embodiments, a plurality of support members (14) include a first support member (141) and a second support member (142), and on the same side of the base member (15), the height (H1) of the first support member (141) protruding from the first surface (151) is greater than the height (H2) of the second support member (142) protruding from the first surface (151).

[0168] The first support member (141) may be one or more. The second support member (142) may be one or more. Optionally, both the first support member (141) and the second support member (142) are multiple.

[0169] The first support member (141) has a relatively large height, which supports the positive plate (11) or the negative plate (12) and can form a relatively large gap (G), thus providing more space for the expansion of the negative plate (12). The second support member (142) has a relatively small height, so the space it occupies is also relatively small. As the negative plate (12) expands, the gap (G) gradually shrinks; and since the second support member (142) can receive pressure only after the negative plate (12) has expanded to some extent, it can reduce the pressure received by the negative plate (12) during the initial expansion. When the second support member (142) receives pressure, the second support member (142) can relieve the expansion of the negative plate (12) to some extent and reduce the electrolyte extruded by the negative plate (12), thereby improving the circulation performance of the cylindrical battery cell (7).

[0170] In some embodiments, the first support member (141) is a plurality, and the second support member (142) is a plurality.

[0171] In some embodiments, the height of the first support member (141) is 1.1 to 15 times the height of the second support member (142), and optionally 2 to 7 times.

[0172] In some embodiments, the separating member (13) includes a separating base portion (131) and a plurality of support portions (14). Optionally, the plurality of support portions (14) of the separating member (13) include a first support portion (141) and a second support portion (142).

[0173] In some embodiments, at least one of the positive electrode (11), the negative electrode (12), and the separating member (13) comprises a plurality of organic particles (P), and the support member (14) comprises organic particles (P).

[0174] For example, in the electrode assembly (10), an organic particle (P) may be installed in one of the positive electrode (11), the negative electrode (12), and the separating member (13), an organic particle (P) may be installed in both, and an organic particle (P) may also be installed in all three.

[0175] The organic particles (P) can act as supports to form a gap (G). When thermal runaway occurs in the cylindrical battery cell (7), the organic particles (P) can form a gel film structure at high temperatures, thereby reducing the diffusion pathway of active ions and delaying the thermal diffusion time, which can improve the reliability of the cylindrical battery cell (7).

[0176] For example, organic particles (P) can be formed on the anode (11), cathode (12), or separator (13) through a coating method. By forming the support (14) by coating the organic particles (P), the molding process can be simplified.

[0177] In some embodiments, a plurality of organic particles (P) include a first organic particle (P1) and a second organic particle (P2), and the number average particle size of the first organic particle (P1) is larger than the number average particle size of the second organic particle (P2).

[0178] What needs to be explained is that the number-average path of organic particles is the arithmetic mean of the particle sizes of organic particles calculated statistically based on the number of organic particles. The particle size of an organic particle can refer to the distance between the two points farthest from the organic particle.

[0179] A first organic particle (P1) with a relatively large number average particle size can support the positive plate (11) or the negative plate (12) to form a relatively large gap (G), thereby providing more space for the expansion of the negative plate (12). A second organic particle (P2) with a relatively small number average particle size can only receive pressure after the negative plate (12) has expanded to some extent, thus reducing the pressure received by the negative plate (12) during the initial expansion. When the second organic particle (P2) receives pressure, the second organic particle (P2) can relieve the expansion of the negative plate (12) to some extent and reduce the electrolyte extruded by the negative plate (12), thereby improving the circulation performance of the cylindrical battery cell (7).

[0180] In some embodiments, a plurality of support members (14) include a first support member (141) and a second support member (142), and on the same side of the base member (15), the height of the first support member (141) protruding from the first surface is greater than the height of the second support member (142) protruding from the first surface. The organic particle (P) includes a first organic particle (P1) and a second organic particle (P2); the first support member (141) includes the first organic particle (P1), and the second support member (142) includes the second organic particle (P2).

[0181] By installing a first organic particle (P1) and a second organic particle (P2) with different number average particle sizes, a first support member (141) and a second support member (142) with different heights can be formed. The first support member (141) has a relatively large height, which supports the positive plate (11) or the negative plate (12) and can form a relatively large gap (G), thus providing more space for the expansion of the negative plate (12). The second support member (142) can receive pressure only after the negative plate (12) has expanded to some extent, so the pressure received by the negative plate (12) during the initial expansion can be reduced. When the second support member (142) receives pressure, the second support member (142) can relieve the expansion of the negative plate (12) to some extent and reduce the electrolyte extruded by the negative plate (12), thereby improving the circulation performance of the cylindrical battery cell (7).

[0182] In some embodiments, the number average particle size of the first organic particle (P1) is >10 μm, and the number average particle size of the second organic particle (P2) is 2 μm to 10 μm.

[0183] In some embodiments, the number average particle size of the first organic particle (P1) is 12 μm to 25 μm. For example, the number average particle size of the first organic particle (P1) may be 12 μm, 13 μm, 15 μm, 16 μm, 18 μm, 20 μm, 21 μm, 22 μm, 24 μm, or 25 μm.

[0184] In some embodiments, the number average particle size of the second organic particle (P2) is 2 μm to 9 μm. For example, the number average particle size of the first organic particle (P1) may be 2 μm, 2.5 μm, 3 μm, 4 μm, 5 μm, 5.5 μm, 6 μm, 7 μm, 8 μm, or 9 μm.

[0185] In some embodiments, the ratio of the number average particle size of the first organic particle (P1) to the number average particle size of the second organic particle (P2) is 1.5 or greater.

[0186] In some embodiments, the first organic particle (P1) is a secondary particle.

[0187] In some embodiments, the second organic particle (P2) is a primary particle.

[0188] It must be explained that primary particles and secondary particles have the meanings known in the art. Primary particles refer to particles that do not form an aggregated state. Secondary particles refer to particles in the form of aggregates formed by the aggregation of two or more primary particles.

[0189] In some embodiments, a plurality of organic particles (P) comprise a first organic particle (P1), and the first organic particle (P1) comprises one or more of a homopolymer or copolymer of fluorine-containing 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 alkylene oxide monomer units, and a modified compound of each of the above-described homopolymer or copolymer.

[0190] In some embodiments, the fluorine-containing alkenyl monomer unit may be selected from one or more of difluoroethylene, vinylidene fluoride, trifluoroethylene, chlorotrifluoroethylene, tetrafluoroethylene, and hexafluoropropylene.

[0191] In some embodiments, the olefin monomer unit may be selected from one or more of ethylene, propylene, butadiene, isoprene, etc.

[0192] In some embodiments, the unsaturated nitrile-based monomer unit may be selected from one or more of acrylonitrile, methacrylonitrile, etc.

[0193] In some embodiments, the alkylene oxide-based monomer unit may be selected from one or more of ethylene oxide, propylene oxide, etc.

[0194] In some embodiments, the first organic particle (P1) comprises one or more of polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinyl fluoride, polyvinylidene fluoride, polyethylene, polypropylene, polyacrylonitrile, polyethylene oxide, copolymers of different fluorine-containing alkenyl monomer units, copolymers of fluorine-containing alkenyl monomer units and olefin monomer units, copolymers of fluorine-containing alkenyl monomer units and acrylic acid monomer units, copolymers of fluorine-containing alkenyl monomer units and acrylate monomer units, and modified compounds of each of the above-described homopolymers or copolymers.

[0195] In some embodiments, the first organic particle (P1) may comprise one or more of vinylidene fluoride-trifluoroethylene copolymer, vinylidene fluoride-hexafluoropropylene copolymer, vinylidene fluoride-trifluoroethylene-hexafluoropropylene copolymer, vinylidene fluoride-hexafluoropropylene-acrylic acid copolymer, vinylidene fluoride-hexafluoropropylene-acrylate copolymer, and a modified compound of the copolymers described above.

[0196] In some embodiments, a plurality of organic particles (P) include a second organic particle (P2), and the second organic particle (P2) includes one or more of an acrylate-based monomer unit homopolymer or copolymer, an acrylic acid-based monomer unit homopolymer or copolymer, a styrene-based monomer unit homopolymer or copolymer, a polyurethane-based compound, a rubber-based compound, and a modified compound of each of the above-mentioned homopolymer or copolymer.

[0197] In some embodiments, the second organic particle (P2) comprises one or more of a copolymer of an acrylate monomer unit and a styrene monomer unit, a copolymer of an acrylic acid monomer unit and a styrene monomer unit, a copolymer of an acrylic acid 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 the copolymers described above.

[0198] In some embodiments, the acrylate monomer unit may be selected from one or more of methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, methyl methacrylate, butyl methacrylate, isooctyl methacrylate, etc.

[0199] In some embodiments, the acrylic acid-based monomer unit may be selected from one or more of acrylic acid, methacrylic acid, etc.

[0200] In some embodiments, the styrene-based monomer unit may be selected from one or more of styrene, methyl styrene, etc.

[0201] In some embodiments, the unsaturated nitrile-based monomer unit may be selected from one or more of acrylonitrile, methacrylonitrile, etc.

[0202] In some embodiments, the second organic particle (P2) is a 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 It may include one or more of methacrylate-styrene-acrylonitrile copolymer, styrene-vinyl acetate copolymer, styrene-vinyl acetate-pyrrolidone copolymer, and modification compounds of each of the above-mentioned materials.

[0203] In some embodiments, the separating member (13) includes a base portion (15) and a plurality of support portions (14), and the support portions (14) include organic particles installed on the base portion.

[0204] The organic particles (P) may protrude entirely from the base portion (15). Alternatively, some of the organic particles are inserted into the base portion (15), and other parts protrude from the base portion (15).

[0205] The organic particles (P) can support the positive plate (11) or the negative plate (12) to increase the gap (G) and provide space for the expansion of the negative plate (12).

[0206] To simplify the explanation, the base portion (15) of the separating member (13) may be referred to as the separating base portion (131).

[0207] In some embodiments, the base portion (15) of the separation member (13) comprises a base membrane (13a) and an inorganic particle layer (P3) installed on the base membrane (13a), and organic particles (P) protrude at least partially from the inorganic particle layer (P3).

[0208] The inorganic particle layer (P3) contains a plurality of inorganic particles, and a sufficient and non-uniformly distributed gap is formed between the inorganic particles and the organic particles, thereby improving the air permeability of the separating member so that the cylindrical battery cell can have excellent circulation performance and reliability.

[0209] In some embodiments, the separation member (13) includes a coating layer (13b) installed on at least one surface of the base membrane (13a). The coating layer (13b) includes an inorganic particle layer (P3) and a plurality of organic particles (P).

[0210] In some examples, inorganic particles are first coated on the base membrane (13a) to form an inorganic particle layer (P3), and then a plurality of organic particles can be coated on the inorganic particle layer (P3). In other examples, inorganic particles and organic particles are first mixed and then coated together on the anode base membrane (13a).

[0211] In some examples, one surface of the base membrane (13a) is coated with a coating layer (13b) comprising an inorganic particle layer (P3) and a plurality of organic particles (P), and the other surface of the base membrane (13a) may not have a coating layer and may be coated with an inorganic particle layer (P3). In some other examples, both surfaces of the base membrane (13a) are coated with a coating layer (13b) comprising an inorganic particle layer (P3) and organic particles (P).

[0212] Since a sufficient and unevenly distributed gap is formed between the inorganic particles and the organic particles (P), the air permeability of the separating member (13) is improved, so that the cylindrical battery cell (7) can have excellent circulation performance and reliability. The organic particles (P) can support the positive plate (11) or the negative plate (12), thereby increasing the gap (G) and providing space for the expansion of the negative plate (12).

[0213] In some embodiments, the inorganic particles may 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).

[0214] 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 may be 0.5 μm to 2.5 μm, 1.5 μm to 2.5 μm, 0.3 μm to 0.7 μm, etc.

[0215] In some embodiments, a coating layer (13b) is coated on the surface of the base film (13a) facing the positive electrode (11), and / or, a coating layer (13b) is coated on the surface of the base film (13a) facing the negative electrode (12).

[0216] In some embodiments, the radial size W of at least some gaps (G) is 5 μm to 60 μm.

[0217] For example, the radial size of the gap (G) may be the size of the gap (G) along the radial direction of a cylindrical battery cell. The radial size W of the gap (G) at different locations may be the same or different.

[0218] Optionally, the radial size W of each part of the gap (G) is 5μm to 60μm.

[0219] Optionally, the radial size W of the gap (G) may be a range consisting of 5 μm, 6 μm, 8 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm, 60 μm, or any two of the values ​​mentioned above.

[0220] For example, the radial size of the gap (G) can be measured according to the following method:

[0221] Discharging a cylindrical battery cell to a lower cutoff voltage (e.g., 2.5V);

[0222] Using CT (Computed Tomography) technology, a cross-sectional image of the electrode assembly is obtained using X-rays, the cross-section is perpendicular to the axial direction of the cylindrical battery cell, and the cross-section represents the positive film layer, the negative film layer, and the separator;

[0223] Based on the image, the distance D1 between the outer surface of the 6th layer anode piece and the inner surface of the 10th layer anode piece is measured in the radial direction of the electrode assembly;

[0224] The cylindrical battery cell is disassembled to measure the thickness t1 of the positive electrode, the thickness t2 of the negative electrode, and the thickness t3 of the separator.

[0225] A 3-layer anode, a 4-layer cathode, and an 8-layer separator are installed between the outer surface of the 6th layer anode and the inner surface of the 10th layer anode; and an 8-layer gap is formed between the outer surface of the 6th layer anode and the inner surface of the 10th layer anode. W=(D1-3Хt1-4Хt2-8Хt3) / 8.

[0226] It needs to be explained that D1 is measured at a location on the outer surface of the 6th layer anode piece where no support is installed and at a location on the inner surface of the 10th layer anode piece where no support is installed. For example, based on the image, a virtual line is established, and the virtual line may pass through the center of the cross-section. Based on the image and the virtual line, a first intersection point between the outer surface of the 6th layer anode piece and the virtual line is obtained along a direction away from the center of the cross-section and parallel to the virtual line, and a second intersection point between the inner surface of the 10th layer anode piece and the virtual line is obtained. Then, the distance between the first and second intersection points is measured, and the distance can be indicated as D1.

[0227] t1 is measured in the part of the anode where the anode film layer is installed and the support is not installed. For example, in the part of the anode where the support is not installed, 50 locations are randomly selected, 50 thickness values ​​are measured, the average of the 50 thickness values ​​is calculated, and the average value can be indicated as t1.

[0228] Thickness t2 is measured in the part of the cathode where the cathode film layer is installed and the support is not installed. For example, in the part of the cathode where the support is not installed, 50 locations are randomly selected, 50 thickness values ​​are measured, the average of the 50 thickness values ​​is calculated, and the average value can be indicated as t2.

[0229] The thickness t3 is measured in the part of the separating member where no support is installed. For example, in the part of the separating member where no support is installed, 50 locations are randomly selected, 50 thickness values ​​are measured, the average of the 50 thickness values ​​is calculated, and the average value is indicated as t3.

[0230] In the embodiment of the present application, by limiting the radial size W of the gap (G) to 5 μm or more, space can be provided for the expansion of the negative electrode (12), thereby reducing the expansion force, improving the circulation performance of the cylindrical battery cell (7), and lowering the risk of the housing (20) being deformed or cracked. In the embodiment of the present application, by limiting the radial size W of the gap (G) to 60 μm or less, the ion movement path between the positive electrode (11) and the negative electrode (12) is shortened, and the internal resistance of the cylindrical battery cell (7) is reduced, thereby reducing heat generation and reducing the influence of the gap (G) on energy density.

[0231] In some embodiments, the gap (G) includes a first gap (G1) and a second gap (G2), the first gap (G1) is formed between the positive electrode (11) and the separating member (13), and the second gap (G2) is formed between the negative electrode (12) and the separating member (13).

[0232] For example, the radial size of the first gap (G1) is W1, and the radial size of the second gap (G2) is W2. The radial size of the gap (G) is W = W1 + W2.

[0233] Both the first gap (G1) and the second gap (G2) can provide space for the expansion of the negative film layer (12b), thereby reducing the compressive action received by the housing (20) and lowering the risk of the housing (20) being deformed or cracked, which can improve the reliability of the cylindrical battery cell (7).

[0234] In some embodiments, a gap (G) is provided on the inner side of the positive plate (11) and a gap (G) is not provided on the outer side of the positive plate (11), and optionally, the gap located on the inner side of the positive plate (11) includes a first gap (G1) and a second gap (G2).

[0235] In some other embodiments, a gap (G) is provided on the outer side of the positive plate (11) and no gap (G) is provided on the inner side of the positive plate (11), and optionally, the gap (G) located on the outer side of the positive plate (11) includes a first gap (G1) and a second gap (G2).

[0236] In another embodiment, gaps (G) are provided on both the inner and outer sides of the positive plate (11). Optionally, the gap (G) located on the inner side of the positive plate (11) includes a first gap (G1) and a second gap (G2), and the gap located on the outer side of the positive plate (11) includes a first gap (G1) and a second gap (G2). Specifically, one first gap (G1) is formed between the positive plate (11) and the separating member (13) located on the inner side of the positive plate (11), and another first gap (G1) is formed between the positive plate (11) and the separating member (13) located on the outer side of the positive plate (11); A second gap (G2) is formed between the cathode piece (12) and the separating member (13) located on the outside of the cathode piece (12), and another second gap (G2) is formed between the cathode piece (12) and the separating member (13) located on the inside of the cathode piece (12).

[0237] 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 end (E2).

[0238] The gap (G) is wound in several turns along the winding direction (V).

[0239] For example, the positive electrode (11) has a positive winding start end (E3) and a positive winding end end (E4), and the negative electrode (12) has a negative winding start end (E5) and a negative winding end end (E6). Along the winding direction (V), the negative winding end end (E6) extends beyond the positive winding end end (E4); and along the direction opposite to the winding direction (V), the negative winding start end (E5) extends beyond the positive winding start end (E3). Both ends of the negative electrode (12) along the winding direction (V) extend beyond the positive electrode (11), and the negative electrode (12) provides an insertion space for active ions detached from the positive electrode (11), thereby reducing the risk of ion detachment. In the radial direction of the cylindrical battery cell, the winding start end (E1) of the gap (G) corresponds to the positive winding start end (E3), and the winding end end (E2) of the gap (G) corresponds to the positive winding end end (E4).

[0240] In some embodiments, the gap (G) is installed in two places, and the two gaps (G) are installed on each side of the positive plate (11).

[0241] For example, in the radial direction of the cylindrical battery cell (7), the winding start end (E1) of the gap (G) located on the inner side of the positive plate (11) is located on the inner side of the positive plate winding start end (E3), and the winding start end (E1) of the gap (G) located on the outer side of the positive plate (11) is located on the outer side of the positive plate winding start end (E3).

[0242] In an embodiment of the present application, by installing two gaps (G), the expansion amount of the electrode assembly (10) can be further reduced, thereby reducing the compression action received by the housing (20) and lowering the risk of the housing (20) being deformed or cracked, thereby improving the reliability of the cylindrical battery cell.

[0243] In some embodiments, a center hole (10d) is installed in the middle of the electrode assembly (10).

[0244] The center hole (10d) can provide space for the expansion of the negative film layer, thereby reducing the compression action received by the housing (20) and lowering the risk of the housing (20) being deformed or cracked, which can improve the reliability of the cylindrical battery cell (7).

[0245] The center hole (10d) is used as a flow passage for the electrolyte, which can improve the infiltration effect of the electrolyte into the electrode assembly (10). In the event of thermal runaway in the cylindrical battery cell (7), the center hole (10d) is used as a gas discharge passage, which can improve the gas discharge speed and reduce the risk of explosion.

[0246] FIG. 9 is a partial schematic cross-sectional view of an electrode assembly of a cylindrical battery cell provided in another embodiment of the present application; FIG. 10 is a schematic view of a separating member of an electrode assembly of a cylindrical battery cell provided in another embodiment of the present application.

[0247] Referring to FIGS. 9 and 10, in some embodiments, a plurality of support members (14) are installed on both sides of the separating member (13). By installing a plurality of support members (14) on both sides of the separating member (13), the gap (G) can be increased, and more space can be provided for the expansion of the cathode piece (12).

[0248] In some embodiments, the gap (G) includes a first gap (G1) and a second gap (G2), the first gap (G1) is formed between the positive electrode (11) and the separating member (13), and the second gap (G2) is formed between the negative electrode (12) and the separating member (13).

[0249] For example, the radial size of the first gap (G1) is W1, and the radial size of the second gap (G2) is W2. The radial size of the gap (G) is W = W1 + W2.

[0250] In the thickness direction of the separating member (13), the supporting members (14) located on both sides of the separating member (13) may or may not overlap.

[0251] By installing a plurality of support members (14) on both sides of the separating member (13), a first gap (G1) and a second gap (G2) are formed on each side of the separating member (13), thereby providing more space for the expansion of the cathode piece (12).

[0252] In some embodiments, a coating layer (13b) is installed on both sides of the base membrane (13a).

[0253] FIG. 11 is a partial schematic cross-sectional view of an electrode assembly of a cylindrical battery cell provided in another embodiment of the present application; FIG. 12 is a schematic view of a positive electrode piece of an electrode assembly provided in some embodiment of the present application unfolded flat; FIG. 13 is a schematic cross-sectional view of a positive electrode piece of an electrode assembly provided in some embodiment of the present application; and FIG. 14 is a schematic cross-sectional view of a negative electrode piece of an electrode assembly provided in some embodiment of the present application.

[0254] Referring to FIGS. 11 to 14, in some embodiments, a support member (14) is installed on the positive plate (11).

[0255] In an embodiment of the present application, a support member (14) may be installed on one side of the positive plate (11), and support members (14) may be installed on both sides of the positive plate (11).

[0256] In some embodiments, the anode piece (11) includes an anode base portion (111) and a plurality of anode protrusions (112) protruding from the surface of the anode base portion (111), and an anode recess (113) corresponding to the position of the anode protrusion (112) is installed on one side of the anode piece (11) far from the anode protrusion (112). The support portion (14) of the anode piece (11) includes the anode protrusion (112).

[0257] For example, the number of positive concave portions (113) and positive protrusions (112) are the same and are installed in a one-to-one correspondence.

[0258] The positive projection (112) can support the separating member (13) and the negative plate (12) to form a gap (G). The positive recess (113) can accommodate an electrolyte and can also provide space for the expansion of the negative plate (12).

[0259] For example, the positive protrusion (112) and positive concave portion (113) can be formed by punching the positive plate (11).

[0260] In some embodiments, organic particles may be installed on the surface of the anode protrusion (112).

[0261] In some embodiments, the positive plate (11) includes a positive tab, and the positive tab is connected to the positive base portion (111).

[0262] In some embodiments, all positive protrusions (112) protrude toward the same side of the positive base portion (111). Correspondingly, a plurality of support portions (14) are installed on the same side of the positive base portion (111).

[0263] The embodiment of the present application can simplify the molding process of the anode piece (11).

[0264] In some embodiments, the anode protrusions (112) are multiple, and some anode protrusions (112) protruding from the anode base portion (111) have a relatively high height, while other anode protrusions (112) protruding from the anode base portion (111) have a relatively low height. The first support portion includes an anode protrusion (112) with a relatively high height, and the second support portion includes an anode protrusion (112) with a relatively low height.

[0265] In some embodiments, a plurality of support members (14) are installed on one side of the separating member (13) facing the positive recess (113), and at least some of the plurality of support members (14) of the separating member (13) and the positive recess (113) do not overlap in the radial direction.

[0266] In some embodiments, the positive plate (11) comprises a positive current collector (11a) and a positive film layer (11b) installed on the surface of the positive current collector (11a). For example, the portion of the positive current collector (11a) where the positive film layer (11b) is not installed may be a positive tab.

[0267] In some embodiments, the positive projection (112) is formed in the region where the positive film layer (11b) is installed on the positive plate (11).

[0268] In some embodiments, the cathode piece (12) comprises a cathode current collector (12a) and a cathode film layer (12b) installed on at least one side of the cathode current collector (12a) and containing a cathode active material.

[0269] For example, the portion of the negative current collector (12a) that is not installed on the negative film layer (12b) may be a negative tab.

[0270] In some embodiments, the negative electrode active material comprises a silicon-based material. The introduction of the silicon-based material can improve the capacity of the negative electrode active material, thereby improving the energy density of the cylindrical battery cell (7); and the gap (G) provides space for the expansion of the silicon-based material, thereby reducing the influence of the silicon-based material on the expansion force.

[0271] For example, the silicon element may exist in the form of a silicon-based material, and, for example, the silicon-based material may include at least one of single-element silicon, silicon-oxygen compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys.

[0272] In some embodiments, the mass content of silicon elements in the silicon-based material in the cathode film layer (12b) is 2% to 19%. For example, the mass content of silicon elements in the cathode film layer may be a range consisting of 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19% or any two of the above values.

[0273] The mass content of silicon elements in the cathode film layer has a meaning known in the art and can be detected using devices and methods known in the art. For example, the cathode piece is immersed in a solvent (e.g., water) to separate the cathode active material from the cathode current collector, and each material in the cathode film layer is obtained by vacuum filtration, and then used as a test sample. The test sample is then detected using an ICAP7400 inductively coupled plasma photoemission spectrometer from Thermo Fisher Scientific, USA, and the silicon element content can be obtained by referring to the GB / T30902-2014 standard.

[0274] The embodiment of the present application improves the capacity of the negative electrode by limiting the mass content of silicon elements in the negative electrode film layer (12b) to 2% or more, thereby improving the energy density of the cylindrical battery cell; the gap (G) provides space for the expansion of the negative electrode, thereby reducing the influence of the silicon-based material on the expansion force. The embodiment of the present application improves the circulation performance of the cylindrical battery cell by limiting the expansion amount of the cylindrical battery cell by limiting the mass content of silicon elements in the negative electrode film layer (12b) to 19% or less.

[0275] In the embodiment of the present application, by limiting the mass content of silicon elements in the negative electrode film layer (12b) to 2% to 19%, the expansion and capacity of the negative electrode are balanced to some extent, and the circulation performance and energy density of the cylindrical battery cell are combined.

[0276] In some embodiments, the mass content of silicon element in the cathode film layer (12b) is 6% to 13%.

[0277] In some embodiments, the capacity area density of the negative electrode (12) is 3.2 mAh / cm² 2 That is all.

[0278] The capacity areal density of the negative electrode has a meaning known in the art and can be detected using devices and methods known in the art. For example, the negative electrode and the metal lithium sheet described above are configured as counter electrodes, and together with an electrolyte and a separator, a CR2430 type button battery is assembled in an argon atmosphere glove box; after standing the obtained button battery for 12 hours, it is discharged to 0.005V with a constant current of 0.05C at 25°C, then stood for 10 minutes, then discharged again to 0.005V with a constant current of 50μA, then stood for 10 minutes, then discharged again to 0.005V with a constant current of 10μA; then charged to 2V with a constant current of 0.1C, and the charge capacity is recorded, and the ratio of the charge capacity to the area of ​​the negative electrode is the capacity areal density. As an example, the electrolyte and separator of Example 1 described below may be used.

[0279] The areal density of the cathode is related to the expansion of the cathode. The embodiments of the present application can reduce the influence of the areal density of the cathode on the expansion force by installing a gap, and accordingly, the capacity of the cathode can be improved, thereby improving the energy density of the cylindrical battery cell.

[0280] For example, the capacity area density of the negative electrode (12) is 3.2 mAh / cm² 2 , 3.3mAh / cm 2 , 3.33mAh / cm 2 , 3.5mAh / cm 2 , 3.8mAh / cm 2 , 3.9mAh / cm 2 , 4mAh / cm 2 , 4.2mAh / cm 2 , 4.5mAh / cm2 , 4.8mAh / cm 2 , 4.9mAh / cm 2 , 5mAh / cm 2 , 5.2mAh / cm 2 , 5.5mAh / cm 2 , 5.8mAh / cm 2 , 6mAh / cm 2 , 6.2mAh / cm 2 , 6.5mAh / cm 2 , 6.8mAh / cm 2 , 7mAh / cm 2 , 7.5mAh / cm 2 , 8mAh / cm 2 , 8.5mAh / cm 2 , 9mAh / cm 2 , 9.5mAh / cm 2 , 10mAh / cm 2 , 10.5mAh / cm 2 , 11mAh / cm 2 , 11.5mAh / cm 2 Or it may be a range consisting of any two values ​​as described above.

[0281] In some embodiments, the capacity area density of the negative electrode (12) is 3.3 mAh / cm² 2 Up to 11.5mAh / cm 2 The embodiments of the present application can balance the capacity and expansion of the negative electrode to some extent, and can combine the energy density and circulation performance of a cylindrical battery cell.

[0282] In some embodiments, the capacity area density of the negative electrode (12) is 3.96 mAh / cm² 2 Up to 7.56mAh / cm² 2 As a result, it is possible to further combine the energy density and circulation performance of cylindrical battery cells.

[0283] In some embodiments, a plurality of support members (14) are installed on the cathode member (12).

[0284] In an embodiment of the present application, a plurality of support members (14) may be installed on one side of the cathode piece (12), and a plurality of support members (14) may be installed on both sides of the cathode piece (12).

[0285] In some embodiments, the cathode piece (12) includes a cathode base portion (121) and a plurality of cathode protrusions (122) protruding from the surface of the cathode base portion (121), and a cathode recess (123) corresponding to the position of the cathode protrusion (122) is installed on one side of the cathode piece (12) far from the cathode protrusion (122). The support portion (14) of the cathode piece (12) includes the cathode protrusion (122).

[0286] For example, the number of cathode concave portions (123) and cathode protrusions (122) are the same and are installed in a one-to-one correspondence.

[0287] The cathode protrusion (122) can support the separating member (13) and the anode piece (11) to form a gap (G). The cathode recess (123) can accommodate an electrolyte and can also provide space for the expansion of the cathode piece (12).

[0288] For example, the cathode protrusion (122) and the cathode concave portion (123) can be formed by punching the cathode piece (12).

[0289] In some embodiments, organic particles may be installed on the surface of the cathode protrusion (122).

[0290] In some embodiments, the cathode portion includes a cathode tab, and the cathode tab is connected to the cathode base portion (121).

[0291] In some embodiments, the cathode protrusions (122) are multiple.

[0292] In some embodiments, all cathode protrusions (122) protrude toward the same side of the cathode base portion (121). Correspondingly, a plurality of support portions (14) are installed on the same side of the cathode base portion (121).

[0293] The embodiment of the present application can simplify the molding process of the cathode piece (12).

[0294] In some embodiments, the cathode protrusions (122) are multiple, and some cathode protrusions (122) protruding from the cathode base portion (121) have a relatively high height, and other some cathode protrusions (122) protruding from the cathode base portion (121) have a relatively low height. The first support portion includes a cathode protrusion (122) with a relatively high height, and the second support portion includes a cathode protrusion (122) with a relatively low height.

[0295] In some embodiments, a plurality of support members (14) are installed on one side of the separating member (13) facing the cathode recess (123), and at least some of the plurality of support members (14) of the separating member (13) and the cathode recess (123) do not overlap in the radial direction.

[0296] In some embodiments, the cathode projection (122) is formed in the region where the cathode film layer (12b) is installed in the cathode piece (12).

[0297] In some embodiments, a gap (G) is formed between the cathode film layer (12b) and the anode film layer (11b).

[0298] In some embodiments, a plurality of support members (14) are installed on one side of the positive member (11) facing the separating member (13), and a plurality of support members (14) are installed on one side of the separating member (13) facing the positive member (11), and the plurality of support members (14) of the positive member (11) facing the separating member (13) are installed at least partially opposite to the plurality of support members (14) of the separating member (13) facing the positive member (11).

[0299] Optionally, a support is not installed on the cathode piece (12).

[0300] For example, separating members (13) are installed on both sides of the positive plate (11), the separating member (13) located inside the positive plate (11) is referred to as the internal separating member, and the separating member (13) located outside the positive plate (11) is referred to as the external separating member;

[0301] In some examples, a plurality of support members (14) are installed on one side of the positive plate (11) facing the internal separation member, and a plurality of support members (14) are installed on one side of the internal separation member facing the positive plate (11), and the plurality of support members (14) of the positive plate (11) are installed to face at least partially the plurality of support members (14) of the internal separation member. For example, a plurality of positive protrusions (112) of the positive plate (11) face at least partially the plurality of organic particles of the internal separation member.

[0302] In some other examples, a plurality of support members (14) are installed on one side of the positive plate (11) facing the external separation member, and a plurality of support members (14) are installed on one side of the external separation member facing the positive plate (11), and the plurality of support members (14) of the positive plate (11) are installed to face at least partially the plurality of support members (14) of the external separation member. For example, a plurality of positive protrusions (112) of the positive plate (11) face at least partially the plurality of organic particles of the external separation member.

[0303] In another example, multiple support members (14) are installed on both sides of the positive plate (11). Multiple support members (14) are installed on one side of the internal separating member facing the positive plate (11), and multiple support members (14) are installed on one side of the external separating member facing the positive plate (11). The multiple support members (14) of the positive plate (11) facing the internal separating member are at least partially opposed to the multiple support members (14) of the internal separating member facing the positive plate (11), and the multiple support members (14) of the positive plate (11) facing the external separating member are at least partially opposed to the multiple support members (14) of the external separating member facing the positive plate (11).

[0304] By installing a plurality of support members (14) of the positive electrode (11) facing the plurality of support members (14) of the separating member (13), the plurality of support members (14) of the positive electrode (11) and the plurality of support members (14) of the separating member (13) are at least partially in contact, thereby increasing the gap (G) and providing more space for the expansion of the negative electrode (12).

[0305] For example, an embodiment of the present application can reduce the depth of the anode recess (113) and the particle size of the organic particles, thereby reducing damage to the anode piece (11) during the punching process and improving the cycle life of the cylindrical battery cell (7).

[0306] In some embodiments, a plurality of support members (14) are installed on one side of the cathode member (12) facing the separation member (13), and a plurality of support members (14) are installed on one side of the separation member (13) facing the cathode member (12), and the plurality of support members (14) of the cathode member (12) facing the separation member (13) are installed at least partially opposite to the plurality of support members (14) of the separation member (13) facing the cathode member (12).

[0307] Optionally, a support is not installed on the positive plate (11).

[0308] For example, separating members (13) are installed on both sides of the cathode piece (12), the separating member (13) located inside the cathode piece (12) is referred to as the internal separating member, and the separating member (13) located outside the cathode piece (12) is referred to as the external separating member;

[0309] In some examples, a plurality of support members (14) are installed on one side of the cathode piece (12) facing the internal separation member, and a plurality of support members (14) are installed on one side of the internal separation member facing the cathode piece (12), and the plurality of support members (14) of the cathode piece (12) are installed to face at least partially the plurality of support members (14) of the internal separation member. For example, a plurality of cathode protrusions (122) of the cathode piece (12) face at least partially the plurality of organic particles of the internal separation member.

[0310] In some other examples, a plurality of support members (14) are installed on one side of a cathode piece (12) facing an external separation member, and a plurality of support members (14) are installed on one side of an external separation member facing the cathode piece (12), and the plurality of support members (14) of the cathode piece (12) are installed to face at least partially the plurality of support members (14) of the external separation member. For example, a plurality of cathode protrusions (122) of the cathode piece (12) face at least partially the plurality of organic particles of the external separation member.

[0311] In another example, multiple support members (14) are installed on both sides of the cathode member (12). Multiple support members (14) are installed on one side of the internal separation member facing the cathode member (12), and multiple support members (14) are installed on one side of the external separation member facing the cathode member (12). The multiple support members (14) of the cathode member (12) facing the internal separation member are at least partially opposed to the multiple support members (14) of the internal separation member facing the cathode member (12), and the multiple support members (14) of the cathode member (12) facing the external separation member are at least partially opposed to the multiple support members (14) of the external separation member facing the cathode member (12).

[0312] By installing a plurality of support portions (14) of the cathode piece (12) facing the plurality of support portions (14) of the separating member (13), the plurality of support portions (14) of the cathode piece (12) and the plurality of support portions (14) of the separating member (13) come into at least partial contact, thereby increasing the gap (G) and providing more space for the expansion of the cathode piece (12).

[0313] For example, an embodiment of the present application can reduce the depth of the cathode recess (123) and the particle size of the organic particle (P), thereby reducing damage to the cathode piece (12) during the punching process and improving the cycle life of the cylindrical battery cell (7).

[0314] In some embodiments, a plurality of support members (14) are installed on one side of the cathode member (12) facing the positive member (11), and a plurality of support members (14) are installed on one side of the positive member (11) facing the negative member (12), and the plurality of support members (14) of the negative member (12) facing the positive member (11) are installed opposite to at least a portion of the plurality of support members (14) of the positive member (11) facing the negative member (12).

[0315] Optionally, a support member is not installed on the separation member (13).

[0316] In some examples, a plurality of support members (14) are installed on the outer side of the positive electrode (11), and a plurality of support members (14) are installed on the inner side of the negative electrode (12). The plurality of support members (14) on the outer side of the positive electrode (11) are installed facing the plurality of support members (14) on the inner side of the negative electrode (12) and overlap in the radial direction.

[0317] In some examples, a plurality of support members (14) are installed on the inner side of the positive electrode (11), and a plurality of support members (14) are installed on the outer side of the negative electrode (12). The plurality of support members (14) on the inner side of the positive electrode (11) and the plurality of support members (14) on the outer side of the negative electrode (12) are installed facing each other and overlap in the radial direction.

[0318] In some examples, multiple support members (14) are installed on both the inner and outer sides of the positive electrode (11), and multiple support members (14) are installed on both the inner and outer sides of the negative electrode (12); the multiple support members (14) on the outer side of the positive electrode (11) and the multiple support members (14) on the inner side of the negative electrode (12) are installed facing each other and overlap in the radial direction, and the multiple support members (14) on the inner side of the positive electrode (11) and the multiple support members (14) on the outer side of the negative electrode (12) are installed facing each other and overlap in the radial direction.

[0319] By installing a plurality of support members (14) of the negative electrode (12) facing the plurality of support members (14) of the positive electrode (11), the plurality of support members (14) of the negative electrode (12) and the plurality of support members (14) of the positive electrode (11) are supported by each other, thereby increasing the gap (G) and providing more space for the expansion of the negative electrode (12).

[0320] For example, an embodiment of the present application can reduce the depth of the negative electrode recess (123) and the depth of the positive electrode recess (113) to reduce damage to the positive electrode piece (11) and the negative electrode piece (12) during the punching process and improve the cycle life of the cylindrical battery cell (7).

[0321] In some embodiments, a plurality of support members (14) are installed on the positive electrode (11), the negative electrode (12), and the separating member (13).

[0322] Optionally, multiple support members (14) are installed on both sides of the separating member (13).

[0323] Optionally, a plurality of support members (14) are installed on the outer side of the positive electrode (11) and a plurality of support members (14) are installed on the inner side of the negative electrode (12); alternatively, a plurality of support members (14) are installed on the inner side of the positive electrode (11) and a plurality of support members (14) are installed on the outer side of the negative electrode (12).

[0324] FIG. 15 is a schematic cross-sectional view of an anode provided in some other embodiments of the present application.

[0325] Referring to FIG. 15, in some embodiments, the anode piece (11) includes an anode base portion (111) and a plurality of support portions (14), and the support portions (14) include organic particles installed on the anode base portion (111).

[0326] The organic particle (P) may protrude entirely from the anode base portion (111). Alternatively, some of the organic particle is inserted into the anode base portion (111), and other parts protrude from the anode base portion (111).

[0327] The organic particles (P) of the positive plate (11) can support the negative plate (12), thereby increasing the gap (G) and providing space for the expansion of the negative plate (12).

[0328] In some embodiments, the anode base portion (111) comprises a portion of the anode current collector (11a) where the anode film layer (11b) is covered, the anode film layer (11b), and an inorganic particle layer (P3). The anode film layer (11b) is installed on the surface of the anode current collector (11a), and the inorganic particle layer (P3) is coated on the surface of the anode film layer (11b) away from the anode current collector. Organic particles (P) protrude at least partially from the inorganic particle layer (P3).

[0329] The positive film layer (11b) contains a positive active material, and the inorganic particle layer (P3) contains a plurality of inorganic particles.

[0330] In some embodiments, some of the organic particles (P) are inserted into the inorganic particle layer (P3), and some protrude from the inorganic particle layer (P3).

[0331] In some embodiments, the anode piece (11) includes an anode particle coating layer (11c) installed on the surface of the anode film layer (11b). The anode particle coating layer (11c) includes an inorganic particle layer (P3) and a plurality of organic particles (P).

[0332] In some examples, inorganic particles are first coated on the anode film layer (11b) to form an inorganic particle layer (P3), and then a plurality of organic particles can be coated on the inorganic particle layer (P3). In other examples, inorganic particles and organic particles are first mixed and then coated together on the anode film layer (11b).

[0333] For example, the positive particle coating layer (11c) does not contain a positive active material.

[0334] In some embodiments, a plurality of organic particles (P) include a first organic particle (P1) and a second organic particle (P2), and the number average particle size of the first organic particle (P1) is larger than the number average particle size of the second organic particle (P2).

[0335] FIG. 16 is a schematic cross-sectional view of a cathode provided in some other embodiments of the present application.

[0336] Referring to FIG. 16, in some embodiments, the cathode piece (12) includes a cathode base portion (121) and a plurality of support portions (14), and the support portions (14) include organic particles (P) installed on the cathode base portion (121).

[0337] The organic particles (P) may protrude entirely from the cathode base portion (121). Alternatively, some of the organic particles are inserted into the cathode base portion (121), and other parts protrude from the cathode base portion (121).

[0338] The organic particles (P) of the cathode plate (12) can support the anode plate (11), thereby increasing the gap (G) and providing space for the expansion of the cathode plate (12).

[0339] In some embodiments, the cathode base portion (121) comprises a portion of the cathode current collector (12a) where the cathode film layer (12b) is covered, the cathode film layer (12b), and an inorganic particle layer (P3), wherein the cathode film layer (12b) is installed on the surface of the cathode current collector (12a), and the inorganic particle layer (P3) is coated on the surface of the cathode film layer (12b) away from the cathode current collector (12a). The organic particles (P) protrude at least partially from the inorganic particle layer (P3).

[0340] The cathode film layer (12b) contains a cathode active material, and the inorganic particle layer (P3) contains a plurality of inorganic particles.

[0341] In some embodiments, some of the organic particles (P) are inserted into the inorganic particle layer (P3), and some protrude from the inorganic particle layer (P3).

[0342] In some embodiments, the cathode plate (12) includes a cathode particle coating layer (12c) installed on the surface of the cathode film layer (12b). The cathode particle coating layer (12c) includes an inorganic particle layer (P3) and a plurality of organic particles (P).

[0343] In some examples, inorganic particles are first coated on the cathode film layer (12b) to form an inorganic particle layer (P3), and then a plurality of organic particles can be coated on the inorganic particle layer (P3). In other examples, inorganic particles and organic particles are first mixed and then coated together on the cathode film layer (12b).

[0344] For example, the negative particle coating layer (12c) does not contain a negative active material.

[0345] In some embodiments, a plurality of organic particles (P) include a first organic particle (P1) and a second organic particle (P2), and the number average particle size of the first organic particle (P1) is larger than the number average particle size of the second organic particle (P2).

[0346] FIG. 17 is a partial cross-sectional view of an electrode assembly of a cylindrical battery cell provided in some other embodiments of the present application. FIG. 17 illustrates a positive electrode of one turn, a negative electrode of one turn, and a separating member of one turn.

[0347] Referring to FIGS. 6 and FIGS. 17, in some embodiments, the radial size of the portion of the gap (G) near the end of the winding (E2) is larger than the radial size of the portion of the gap (G) near the beginning of the winding (E1).

[0348] In an embodiment of the present application, the radial sizes of different parts along the winding direction (V) in the gap (G) are compared within the same single cross section perpendicular to the axial direction (Z).

[0349] For example, the portion of the gap (G) close to the end of the winding (E2) may be a portion located inside the end of the winding (E2) in the winding direction (V) from the gap (G) and 10 mm away from the end of the winding; and the portion of the gap (G) close to the start of the winding (E1) may be a portion located inside the start of the winding (E1) in the winding direction (V) from the gap (G) and 10 mm away from the start of the winding.

[0350] The gap (G) may be one or multiple. In an embodiment of the present application, the portion of the gap (G) near the winding end (E2) and the portion of the gap (G) near the winding start (E1) are for the same gap (G).

[0351] For example, the radial size of the portion near the winding start end (E1) in the gap (G) may be equal to the sum of the radial size of the portion near the winding start end (E1) in the first gap (G1) and the radial size of the portion near the winding start end (E1) in the second gap (G2).

[0352] For example, the radial size of the portion near the end of the winding (E2) in the gap (G) may be equal to the sum of the radial size of the portion near the end of the winding (E2) in the first gap (G1) and the radial size of the portion near the end of the winding (E2) in the second gap (G2).

[0353] In the circulation process of the cylindrical battery cell (7), the expansion of the negative electrode (12) gradually accumulates from the inside out along the radial direction; in the embodiment of the present application, the portion near the winding end (E2) in the gap (G) has a larger radial size, thereby providing more expansion space for the negative electrode (12), absorbing the accumulated expansion of the negative electrode (12), further reducing the force acting between the electrode assembly (10) and the housing (20), reducing the amount of deformation of the housing (20), and lowering the risk of the housing (20) cracking, thereby improving reliability.

[0354] In some embodiments, the gap (G) is wound along the winding direction (V) to form n winding turns, where n≥20 and n is a natural number. The innermost winding turn is the first winding turn.

[0355] For example, the first winding turn includes a winding start end (E1); the first winding turn extends one full turn along the winding direction (V) from the winding start end (E1).

[0356] For example, the nth winding turn includes a winding end (E2), and the nth winding turn extends from the end of the n-1th winding turn to the winding end (E2) along the winding direction (V).

[0357] For example, the first to the n-1th turn of winding are all full turns; the nth turn of winding may be a full turn or may not be a full turn, for example, the nth turn of winding is a 1 / 4 turn, a 1 / 2 turn or a 3 / 4 turn.

[0358] For example, n is 20, 30, 40, 50, 60, 70, 80, 90, 100, 150, or 200.

[0359] In some embodiments, the gap (G) is installed in two places, and the two gaps (G) are installed on each side of the positive plate (11). For example, the gap (G) located on the inside of the positive plate (11) can be defined as the inner gap, and the gap (G) located on the outside of the positive plate (11) can be defined as the outer gap.

[0360] The inner gap is wound along the winding direction (V) to form n winding turns, and the outer gap is wound along the winding direction (V) to form n winding turns.

[0361] The q-th winding turn of the outer gap is located outside the q-th winding turn of the inner gap and inside the q+1-th winding turn of the inner gap, and 1≤q≤n-1. The n-th winding turn of the outer gap is located outside the n-th winding turn of the inner gap.

[0362] In some embodiments, the radial size of the k-th winding turn is smaller than the radial size of the k+10th winding turn, k is a natural number, and 5≤k≤n-15.

[0363] Any one of the 5th to n-15th winding turns satisfies the aforementioned relationship. For example, the radial size of the 5th winding turn is smaller than the radial size of the 15th winding turn, the radial size of the 6th winding turn is smaller than the radial size of the 16th winding turn, and the radial size of the n-16th winding turn is smaller than the radial size of the n-6th winding turn, and the radial size of the n-15th winding turn is smaller than the radial size of the n-5th winding turn.

[0364] In an embodiment of the present application, the k-th winding turn and the k+10th winding turn are two winding turns of the same single gap (G).

[0365] In an embodiment of the present application, the radial size of the k-th winding turn and the k+10th winding turn are compared within the same cross-section perpendicular to the axial direction (Z).

[0366] The k+10th winding turn is installed on the outside compared to the kth winding turn, and since the radial size of the k+10th winding turn is larger than the radial size of the kth winding turn, the k+10th winding turn provides more expansion space for the cathode film layer of the inner cathode piece (12), so that the accumulated expansion amount of the cathode piece (12) can be absorbed, furthermore, the force acting between the electrode assembly (10) and the housing (20) can be reduced, the amount of deformation of the housing (20) can be reduced, and the risk of the housing (20) cracking can be lowered, thereby improving reliability.

[0367] In some embodiments, the gap (G) is wound along the winding direction (V) to form n winding turns, where n ≥ 20 and n is a natural number. The innermost winding turn is the first winding turn. The average value of the radial size of the n-9th to n-5th winding turns is greater than the average value of the radial size of the 5th to 9th winding turns.

[0368] In an embodiment of the present application, the gap (G) may be one or two. The n-9th to n-5th winding turns and the 5th to 9th winding turns all belong to the same single gap (G).

[0369] In an embodiment of the present application, the radial size of the n-9th to n-5th winding turn and the radial size of the 5th to 9th winding turn are measured and calculated within the same cross-section perpendicular to the axial direction (Z).

[0370] The portion of the gap (G) that is closer to the end of the winding (E2) has a larger radial size, thereby providing more expansion space for the cathode piece (12), absorbing the accumulated expansion of the cathode piece (12), further reducing the force acting between the electrode assembly (10) and the housing (20), reducing the deformation of the housing (20), and lowering the risk of the housing (20) cracking, thereby improving reliability.

[0371] In some embodiments, the radial size of at least some gaps (G) gradually increases along the winding direction (V).

[0372] Since the radial size of the gap (G) changes gradually, the rapid change in the radial size of the gap (G) is reduced, and stress concentration in the negative plate (12) is reduced, thereby improving the circulation performance of the cylindrical battery cell (7).

[0373] In some embodiments, the radial size of the gap (G) at each position can be adjusted by changing the height of the support member (14).

[0374] FIG. 18 is a partial cross-sectional view of an electrode assembly of a cylindrical battery cell provided in some other embodiments of the present application.

[0375] Referring to FIG. 18, in some embodiments, the electrode assembly (10) comprises a middle region (C1) and two end regions (C2) arranged along the axial direction (Z) of a cylindrical battery cell, and the middle region (C1) is located between the two end regions (C2). The radial size of the portion installed in the middle region (C1) in the gap (G) is smaller than the radial size of the portion installed in the end region (C2) in the gap (G).

[0376] For example, the separating member (13) has a first stage (E7) and a second stage (E8) installed oppositely along the axial direction (Z); in the axial direction (Z), the distance between the first stage (E7) and the second stage (E8) is L.

[0377] The end region (C2) is a region having a constant size in the axial direction (Z). One end region (C2) is a region extending for a length L1 from the first end (E7) toward the second end (E8), and the other end region (C2) is a region extending for a length L1 from the second end (E8) toward the first end (E7); the middle region (C1) includes a region extending for a length L2 from the middle section (S) toward the first end (E7) and a region extending for a length L2 from the middle section (S) toward the second end (E8). The middle section (S) is a section perpendicular to the axial direction (Z); and in the axial direction (Z), the distance between the middle section (S) and the first end (E7) is equal to the distance between the middle section (S) and the second end (E8).

[0378] A portion of the positive film layer is installed in the middle region (C1), and another portion is installed in the end region (C2).

[0379] For example, L1 / L is 0.1 to 0.3 and optionally 0.2. For example, L2 / L is 0.03 to 0.2 and optionally 0.1.

[0380] For example, L1 can be 20mm and L2 can be 5mm.

[0381] For example, the radial size of the part installed in the middle region (C1) in the gap (G) and the radial size of the part installed in the end region (C2) in the gap (G) can be measured according to the following method:

[0382] Using CT (Computed Tomography) technology, images of two cross-sections of a cylindrical battery cell are obtained using X-rays, and both cross-sections are perpendicular to the axial direction of the cylindrical battery cell, and each cross-section represents an anode film layer, a cathode film layer, and a separator; wherein one cross-section passes through a middle region (C1) of an electrode assembly and the other cross-section passes through an end region (C2) of an electrode assembly, the cross-section passing through the middle region (C1) is defined as the first cross-section, and the cross-section passing through the end region (C2) is defined as the second cross-section;

[0383] Based on the image of the first cross-section, a first virtual line is established, and the first virtual line can pass through the center of the first cross-section;

[0384] Based on the image of the first cross-section and the first virtual line, the third intersection point between the outer surface of the sixth layer anode and the first virtual line is obtained along a direction away from the center of the first cross-section and parallel to the first virtual line, and the fourth intersection point between the inner surface of the tenth layer anode and the first virtual line is obtained, and then the distance D2 between the third intersection point and the fourth intersection point is measured; wherein, if a support member is not installed on the anode, the third intersection point is formed at a location on the outer surface of the sixth layer anode where the support member is not installed, and the fourth intersection point is formed at a location on the inner surface of the tenth layer anode where the support member is not installed;

[0385] Based on the image of the second cross-section, a second virtual line is established, and the second virtual line can pass through the center of the second cross-section;

[0386] Based on the image of the second cross section and the second virtual line, the fifth intersection point between the outer surface of the sixth layer anode and the second virtual line is obtained along a direction moving away from the center of the second cross section and parallel to the second virtual line, and the sixth intersection point between the inner surface of the tenth layer anode and the second virtual line is obtained, and then the distance D3 between the fifth intersection point and the sixth intersection point is measured; if a support member is installed on the anode, the fifth intersection point is formed at a location on the outer surface of the sixth layer anode where the support member is not installed, and the sixth intersection point is formed at a location on the inner surface of the tenth layer anode where the support member is not installed;

[0387] Disassemble the cylindrical battery cell, and unfold the positive electrode, negative electrode, and separator;

[0388] In the part of the positive plate where no support is installed, 50 locations are randomly selected, 50 thickness values ​​are measured, the average of the 50 thickness values ​​is calculated, and the average value can be denoted as t1;

[0389] In the part of the cathode where no support is installed, 50 locations are randomly selected, 50 thickness values ​​are measured, the average of the 50 thickness values ​​is calculated, and the average value can be denoted as t2;

[0390] In the part of the separated member where the support is not installed, 50 locations can be randomly selected, 50 thickness values ​​can be measured, the average of the 50 thickness values ​​can be calculated, and the average value can be indicated as t3.

[0391] Between the outer surface of the 6th layer anode and the inner surface of the 10th layer anode, a 3rd layer anode, a 4th layer cathode, and an 8th layer separating member are installed; and between the outer surface of the 6th layer anode and the inner surface of the 10th layer anode, an 8th layer gap is formed.

[0392] The radial size of the part installed in the middle region (C1) of the gap (G) may be (D2-3Хt1-4Хt2-8Хt3) / 8. The radial size of the part installed in the end region (C2) of the gap (G) may be (D3-3Хt1-4Хt2-8Хt3) / 8.

[0393] In an embodiment of the present application, the gap (G) has a relatively large radial size in the end region (C2), thereby facilitating the infiltration of the electrolyte into the gap (G), improving the infiltration effect of the electrolyte on the electrode piece and improving the circulation performance of the cylindrical battery cell (7).

[0394] In some embodiments, the radial size of the part installed in the middle region of the gap (G) is 5 μm to 60 μm, and optionally 10 μm to 30 μm.

[0395] In some embodiments, the electrode assembly (10) also includes a transition region (C3) connecting the middle region (C1) and the end region (C2).

[0396] In some embodiments, in the direction in which the two end regions (C2) are oriented toward the middle region (C1), the radial size of the gap (G) shows a decreasing trend, thereby reducing the rapid change in the radial size of the gap (G) and reducing stress concentration in the negative plate (12), thereby improving the circulation performance of the cylindrical battery cell (7).

[0397] In some embodiments, the radial size of the gap (G) in each area can be adjusted by changing the height of the support member (14).

[0398] FIG. 19 is a partial schematic cross-sectional view of an electrode assembly of a cylindrical battery cell provided in another embodiment of the present application; FIG. 20 is a schematic view of the positive electrode of a cylindrical battery cell in an unfolded state provided in another embodiment of the present application; and FIG. 21 is a schematic view of the negative electrode of a cylindrical battery cell in an unfolded state provided in another embodiment of the present application.

[0399] In some embodiments, an anode recess (113) is installed on one side of the anode piece (11) facing the separating member (13).

[0400] The positive concave portion (113) may be one or multiple.

[0401] For example, the anode piece (11) has separating members (13) installed on both sides along its own thickness direction. Optionally, the anode piece (11) has an anode recess (113) installed on one side along its own thickness direction; alternatively, the anode piece (11) has anode recesses (113) installed on both sides along its own thickness direction.

[0402] For example, in the thickness direction of the anode piece (11), the depth of the anode recess (113) is less than or equal to the thickness of the anode film layer (11b). The thickness of the anode film layer (11b) is the thickness of the anode film layer (11b) located on one side of the anode current collector (11a).

[0403] By installing a positive recess (113), the gap between the positive plate (11) and the negative plate (12) can be increased; during the circulation process of the cylindrical battery cell (7), the positive recess (113) provides space for the expansion of the negative film layer (12b), thereby reducing the pressure between the positive plate (11) and the negative plate (12), and accordingly, the compression received by the electrolyte in the internal void of the positive film layer (11b) and the internal void of the negative film layer (12b) can be relieved, the difference in the concentration of the electrolyte in each region inside the electrode plate can be reduced, and the circulation performance of the cylindrical battery cell (7) having a relatively large diameter can be improved. The positive recess (113) can reduce the expansion amount of the electrode assembly (10), thereby reducing the compression action received by the housing (20), and lower the risk of the housing (20) being deformed or cracked, thereby improving the reliability of the cylindrical battery cell (7).

[0404] The positive recess (113) can also receive an electrolyte, which can help the electrolyte infiltrate the positive plate (11) and the negative plate (12).

[0405] In some embodiments, the gap (G) includes an anode depression (113).

[0406] In some embodiments, a protruding support is not installed on the positive plate (11).

[0407] In some embodiments, an anode projection is not installed at a position corresponding to the anode concave portion (113) in the anode piece (11).

[0408] In some embodiments, the positive plate (11) includes a positive film layer (11b), and the positive recess (113) is formed in the positive film layer (11b), so that the influence of the positive recess (113) on the current flow capacity of the positive current collector (11a) can be reduced.

[0409] In some embodiments, in the thickness direction of the anode piece (11), the depth of the anode recess (113) is smaller than the thickness of the anode film layer (11b). Optionally, in the thickness direction of the anode piece (11), the ratio of the depth of the anode recess (113) to the thickness of the anode film layer (11b) is 0.01 to 0.5.

[0410] In some embodiments, the positive recess (113) penetrates the positive film layer (11b) along the axial direction (Z) of the cylindrical battery cell, thereby increasing the gap between the positive plate (11) and the negative plate (12) and improving the penetration of the electrolyte.

[0411] In some embodiments, the positive depression (113) extends along the axial direction (Z).

[0412] In some embodiments, the cross-sectional shape of the anode recess (113) perpendicular to the axial direction (Z) is triangular, trapezoidal, semicircular, or other shape.

[0413] In some embodiments, the positive depression (113) is multiple.

[0414] In some embodiments, at least some of the plurality of positive recesses (113) are installed on the inner side of the positive plate (11). Since the curvature of the inner side of the positive plate (11) is relatively large, by installing the positive recesses (113) on the inner side of the positive plate (11), stress is released, thereby reducing the risk of the positive active material in the positive film layer (11b) falling off.

[0415] In addition, by installing the positive concave portion (113) on the inner side of the positive plate (11), the capacity of the positive film layer (11b) on the inner side of the positive plate (11) is reduced, thereby lowering the risk of ion precipitation occurring in the negative film layer (12b) located on the inner side of the positive film layer (11b).

[0416] In some embodiments, at least some of the plurality of anode recesses (113) are installed on the outer side of the anode piece (11).

[0417] In some embodiments, the anode piece (11) includes a plurality of anode recesses (113) spaced apart along the winding direction (V). The plurality of anode recesses (113) provide space for expansion in different regions of the cathode film layer (12b), thereby reducing pressure between the anode piece (11) and the cathode piece (12).

[0418] In some embodiments, a cathode recess (123) is installed on one side of the cathode piece (12) facing the separating member (13).

[0419] The cathode concave portion (123) may be one or multiple.

[0420] For example, the cathode piece (12) has separating members (13) installed on both sides along its own thickness direction. Optionally, the cathode piece (12) has a cathode recess (123) installed on one side along its own thickness direction; alternatively, the cathode piece (12) has cathode recesses (123) installed on both sides along its own thickness direction.

[0421] For example, in the thickness direction of the cathode piece (12), the depth of the cathode recess (123) is less than or equal to the thickness of the cathode film layer (12b). The thickness of the cathode film layer (12b) is the thickness of the cathode film layer (12b) located on one side of the cathode current collector (12a).

[0422] By installing a negative electrode recess (123), the gap between the positive electrode (11) and the negative electrode (12) can be increased; during the circulation process of the cylindrical battery cell (7), the negative electrode recess (123) provides space for the expansion of the negative electrode film layer (12b), thereby reducing the pressure between the positive electrode (11) and the negative electrode (12), and accordingly, the compression received by the electrolyte in the internal voids of the positive electrode film layer (11b) and the internal voids of the negative electrode film layer (12b) can be relieved, the difference in the concentration of the electrolyte in each region inside the electrode can be reduced, and the circulation performance of the cylindrical battery cell (7) having a relatively large diameter can be improved. The negative electrode recess (123) can reduce the expansion amount of the electrode assembly (10), thereby reducing the compression action received by the housing (20), and lower the risk of the housing (20) being deformed or cracked, thereby improving the reliability of the cylindrical battery cell (7).

[0423] The cathode recess (123) can also accommodate an electrolyte, which can help the electrolyte infiltrate the anode piece (11) and the cathode piece (12).

[0424] In some embodiments, the gap includes a cathode recess (123).

[0425] In some embodiments, the cathode plate (12) includes a cathode film layer (12b), and a cathode recess (123) is formed in the cathode film layer (12b), so that the influence of the cathode recess (123) on the current flow capability of the cathode current collector (12a) can be reduced. The cathode recess (123) can provide space for the expansion of the cathode film layer (12b).

[0426] In some embodiments, the cathode piece (12) is not provided with a protruding support.

[0427] In some embodiments, a cathode projection is not installed at a position corresponding to the cathode recess (123) in the cathode piece (12).

[0428] In some embodiments, in the thickness direction of the cathode plate (12), the depth of the cathode recess (123) is smaller than the thickness of the cathode plate (12). Optionally, in the thickness direction of the cathode plate (12), the ratio of the depth of the cathode recess (123) to the thickness of the cathode plate (12) is 0.01 to 0.5.

[0429] In some embodiments, the negative electrode recess (123) penetrates the negative electrode film layer (12b) along the axial direction (Z) of the cylindrical battery cell, thereby increasing the gap between the positive electrode (11) and the negative electrode (12) and improving the penetration of the electrolyte.

[0430] In some embodiments, the cathode recess (123) extends along the axial direction (Z).

[0431] In some embodiments, the cross-sectional shape of the cathode recess (123) perpendicular to the axial direction (Z) is triangular, trapezoidal, semicircular, or other shape.

[0432] In some embodiments, the cathode recess (123) is multiple.

[0433] In some embodiments, at least some of the plurality of cathode recesses (123) are installed on the inner side of the cathode piece (12). Since the curvature of the inner side of the cathode piece (12) is relatively large, by installing the cathode recesses (123) on the inner side of the cathode piece (12), stress is released, thereby reducing the risk of the cathode active material in the cathode film layer (12b) falling off.

[0434] In some embodiments, at least some of the plurality of cathode recesses (123) are installed on the outside of the cathode piece (12).

[0435] In some embodiments, the cathode piece (12) includes a plurality of cathode recesses (123) spaced apart along the winding direction (V). The plurality of cathode recesses (123) provide space for expansion in different regions of the cathode film layer (12b), thereby reducing pressure between the anode piece (11) and the cathode piece (12).

[0436] FIG. 22 is a schematic cross-sectional view of the battery cell shown in FIG. 4; FIG. 23 is a schematic view of the dotted circle position in FIG. 22 enlarged.

[0437] Referring to FIGS. 4, FIGS. 5, FIGS. 22 and FIGS. 23, in some embodiments, one of the positive electrode (11) and the negative electrode (12) includes a first electrode tab (10a) and the other includes a second electrode tab (10b). In other words, one of the first electrode tab (10a) and the second electrode tab (10b) is a positive electrode tab and the other is a negative electrode tab.

[0438] The first electrode tab (10a) and the second electrode tab (10b) may be located at the same end of the electrode assembly (10) along the axial direction (Z), and may each be located at both ends of the electrode assembly (10) along the axial direction (Z).

[0439] In some embodiments, the portion having an anode film layer in the anode portion (11), the portion having a cathode film layer in the cathode portion (12), and the separating member (13) constitute the electrode body (10c) of the electrode assembly (10). The first electrode tab (10a) and the second electrode tab (10b) are drawn out from one end of the electrode body (10c) or are drawn out from both ends of the electrode body (10c), respectively.

[0440] In some embodiments, the first electrode tab (10a) is wound in multiple turns along the winding direction (V). Optionally, the end of the first electrode tab (10a) is bent by a flattening or smoothing process to form a multilayer structure that is stacked in the axial direction (Z).

[0441] In some embodiments, the second electrode tab (10b) is wound in multiple turns along the winding direction (V). Optionally, the end of the second electrode tab (10b) is bent by a flattening or smoothing process to form a multilayer structure that is stacked in the axial direction (Z).

[0442] In some embodiments, the cylindrical battery cell (7) includes a first electrode lead (7a) and a second electrode lead (7b), the first electrode lead (7a) is electrically connected to a first electrode tab (10a), and the second electrode lead (7b) is electrically connected to a second electrode tab (10b). The first electrode lead (7a) and the second electrode lead (7b) are insulated from each other.

[0443] The first electrode lead-out section (7a) and the second electrode lead-out section (7b) are used for connection with an external circuit to implement charging or discharging of the cylindrical battery cell (7). For example, when a plurality of cylindrical battery cells (7) are grouped and assembled, the first electrode lead-out section (7a) and the second electrode lead-out section (7b) are used for connection with a busbar component.

[0444] The first electrode lead portion (7a) may be an electrode terminal (30) installed in the housing (20). The electrode terminal (30) and the housing (20) are each molded independently and assembled together during the manufacturing process of the cylindrical battery cell (7). For example, the electrode terminal (30) is installed insulatedly on the end cover (22) or the housing body (21).

[0445] Alternatively, the first electrode lead portion (7a) may be part of the housing (20). For example, the first electrode lead portion (7a) may be the end cover (22) of the housing (20), or the first electrode lead portion (7a) may be the end wall (211) of the housing body (21) facing the end cover (22).

[0446] The second electrode outlet (7b) may be an electrode terminal (30) installed in the housing (20). Alternatively, the second electrode outlet (7b) may be a part of the housing (20). For example, the second electrode outlet (7b) may be an end cover (22) of the housing (20), or the second electrode outlet (7b) may be an end wall (211) of the housing body (21) facing the end cover (22).

[0447] In some embodiments, in the axial direction (Z) of the cylindrical battery cell, the first electrode lead (7a) and the second electrode lead (7b) are located on the same side of the electrode assembly (10).

[0448] When a plurality of cylindrical battery cells (7) are grouped and assembled, the first electrode lead portion (7a) and the second electrode lead portion (7b) of the plurality of cylindrical battery cells (7) can be placed on the same side, so it is easy to implement a connection between the busbar component and the first electrode lead portion (7a) and the second electrode lead portion (7b), and the battery structure can be simplified.

[0449] In some embodiments, the housing (20) comprises a housing body (21) and an end cover (22), the housing body (21) comprises a side wall (212) and an end wall (211), the end wall (211) and the end cover (22) are opposite along the axial direction (Z) of the cylindrical battery cell, and the end cover (22) is sealedly connected to the side wall (212).

[0450] The side wall (212) and the end wall (211) may be formed integrally or independently. For example, the side wall (212) and the end wall (211) are formed integrally. For example, the side wall (212) and the end wall (211) are formed independently and connected by welding or other methods.

[0451] The end cover (22) can be installed so as to be insulated from the side wall (212) and can also be electrically connected.

[0452] An opening is provided at one end of the housing body (21) far from the end wall (211), and an end cover (22) is fitted over the opening of the housing body (21) and joined.

[0453] In some embodiments, the side wall (212) and the end wall (211) may be formed integrally.

[0454] In some embodiments, one of the positive electrode (11) and the negative electrode (12) includes a first electrode tab (10a), and the other includes a second electrode tab (10b). The cylindrical battery cell (7) also includes an electrode terminal (30) installed insulatedly on an end wall (211), and one of the first electrode tab (10a) and the second electrode tab (10b) is electrically connected to the electrode terminal (30), and the other is electrically connected to the end wall (211).

[0455] For example, the first electrode tab (10a) is electrically connected to the electrode terminal (30), and the second electrode tab (10b) is electrically connected to the end wall (211). The second electrode tab (10b) may 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 parts.

[0456] One of the electrode terminal (30) and the end wall (211) is used as the first electrode lead-out section (7a), and the other is used as the second electrode lead-out section (7b).

[0457] The electrode terminal (30) and the end wall (211) can be used as two electrodes exposed to the outside of the cylindrical battery cell (7), and since the electrode terminal (30) and the end wall (211) are located on the same side, it is advantageous to group and assemble multiple cylindrical battery cells (7) and to simplify the battery structure.

[0458] In some embodiments, the cylindrical battery cell (7) also includes a first current collector (40), the first current collector (40) is located on one side of the first electrode tab (10a) facing the end wall (211) and is connected to the first electrode tab (10a). The electrode terminal (30) is connected by contacting the surface of the first current collector (40) facing the end wall (211).

[0459] The first current collector (40) acts as a connection to enable an electrical connection between the first electrode tab (10a) and the electrode terminal (30).

[0460] In some embodiments, the first current collector (40) is annular.

[0461] In some embodiments, a terminal recess (31) is installed on one side of the electrode terminal (30) facing the first current collecting member (40), and the lower wall of the terminal recess (31) is welded to the first current collecting member (40).

[0462] By installing a terminal recess (31), the thickness of the lower wall of the terminal recess (31) can be reduced, the power required to weld the electrode terminal (30) and the first current collector (40) from the outside can be reduced, and the risk of particles generated by welding falling into the housing (20) can be lowered, thereby improving the reliability of the cylindrical battery cell (7).

[0463] By installing the terminal recess (31) on the inner side of the electrode terminal (30), the internal space of the cylindrical battery cell (7) can also be increased.

[0464] In some embodiments, a terminal recess (31) is installed on one side of the electrode terminal (30) separated from the first current collector (40).

[0465] In some embodiments, one terminal recess (31) is installed on one side of the electrode terminal (30) facing the first current collecting member (40), and another terminal recess (31) is installed on one side of the electrode terminal (30) away from the first current collecting member (40); and the portions corresponding to the bottom surfaces of the two terminal recesses (31) are welded to the first current collecting member (40).

[0466] In some embodiments, a through hole (32) is installed in the lower wall of the terminal recess (31), and the through hole (32) can be used to inject an electrolyte.

[0467] In some embodiments, the cylindrical battery cell (7) also includes a cover plate (50), the cover plate (50) is connected to the electrode terminal (30) and is used to separate the through hole (32) from the external space of the cylindrical battery cell (7).

[0468] In some embodiments, at least a portion of the cover plate (50) is received in the terminal recess (31). In some embodiments, the first electrode lead includes the cover plate (50) and the electrode terminal (30).

[0469] In some embodiments, the electrode terminal (30) is riveted to the end wall (211).

[0470] In some embodiments, the first electrode tab (10a) is located at one end of the electrode assembly (10) facing the end wall (211), and the second electrode tab (10b) is located at one end of the electrode assembly (10) facing the end cover (22). The cylindrical battery cell (7) also includes a second current collector (60) connected to the second electrode tab (10b); the second current collector (60) is connected to at least one of the end cover (22) and the side wall (212).

[0471] In some examples, the second current collector (60) is connected to the end cover (22), and the end cover (22) is electrically connected to the side wall (212). The second electrode tab (10b) is electrically connected to the end wall (211) through the second current collector (60), the end cover (22), and the side wall (212).

[0472] In some other examples, the second current collector (60) is connected to the side wall (212). The second electrode tab (10b) is electrically connected to the end wall (211) through the second current collector (60) and the side wall (212). Optionally, the end cover (22) is installed so as to be insulated from the side wall (212).

[0473] In some embodiments, the housing (20) includes a side wall (212) installed to surround the electrode assembly (10), and the thickness of the side wall (212) is 0.3 mm to 1.5 mm. The material of the side wall (212) includes steel.

[0474] 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.

[0475] In the embodiment of the present application, the thickness of the side wall (212) has a meaning known in the art and can be measured using devices and methods known in the art, for example, using a screw micrometer or vernier calipers.

[0476] For example, the material of the side wall (212) includes stainless steel.

[0477] The present application can reduce the expansion force of the electrode assembly (10) applied to the side wall (212) by installing a gap (G), and accordingly, the side wall (212) made of steel can have a thickness of 1.5 mm or less, thereby improving the energy density of the cylindrical battery cell (7). The thickness of the side wall (212) made of steel is 0.3 mm or more, which lowers the risk of the side wall (212) being deformed or ruptured by the expansion force of the electrode assembly (10), thereby improving the reliability of the cylindrical battery cell (7).

[0478] The mechanical strength of the side wall (212) is relatively high so that it does not deform easily, and when used together with the silicon-containing negative plate (12), it is more advantageous to improve the energy density of the cylindrical battery cell and at the same time ensure that the cylindrical battery cell has excellent reliability of use.

[0479] In some embodiments, the thickness of the side wall (212) is 0.3 mm to 1.2 mm.

[0480] 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.

[0481] In some embodiments, the capacity areal density of the cathode is 3.2 mAh / cm² 2 The above is the case, and 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. When the negative plate of the above-described capacity planar density is used together with the side wall (212) of the above-described thickness, it is advantageous to improve the energy density of the cylindrical battery cell (7), while simultaneously ensuring that the cylindrical battery cell (7) has excellent usage reliability and improve circulation performance.

[0482] In some embodiments, the material of the end wall (211) is the same as the material of the side wall (212).

[0483] In some embodiments, the material of the end cover (22) is steel.

[0484] In some embodiments, the height of the housing (20) is 1.3 to 4 times the diameter of the housing (20). For example, the height of the housing (20) may be the size of the housing (20) along the axial direction (Z).

[0485] Optionally, the height of the housing (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 housing (20).

[0486] If the housing (20) meets the size requirements described above, the structural stability of the housing (20) is improved, and the reliability of use of the cylindrical battery cell (7) can be improved.

[0487] In some embodiments, the height of the housing (20) is 1.5 to 2.5 times the diameter of the housing (20).

[0488] In some embodiments, the height of the housing (20) is 50 mm to 150 mm. For example, the height of the housing (20) is 50 mm, 55 mm, 60 mm, 65 mm, 70 mm, 75 mm, 80 mm, 85 mm, 90 mm, 95 mm, 100 mm, 105 mm, 110 mm, 115 mm, 120 mm, 125 mm, 130 mm, 135 mm, 140 mm, 145 mm, or 150 mm.

[0489] Optionally, the height of the housing (20) is 60mm to 100mm.

[0490] In some embodiments, the diameter of the housing (20) is 45 mm to 80 mm. For example, the diameter of the housing (20) is 45 mm, 50 mm, 55 mm, 60 mm, 65 mm, 70 mm, 75 mm, or 80 mm.

[0491] Optionally, the diameter of the housing (20) is 45 mm to 60 mm.

[0492] FIG. 24 is a partial schematic cross-sectional view of a battery cell provided in some other embodiments of the present application.

[0493] Referring to FIG. 24, in some embodiments, the first electrode tab (10a) and the second electrode tab (10b) are both located at one end of the electrode assembly (10) facing the end wall (211). The first electrode tab (10a) and the second electrode tab (10b) can share space in the axial direction (Z), thereby improving space utilization and energy density.

[0494] In some embodiments, the cylindrical battery cell (7) includes two electrode terminals (30) installed on the end wall (211), and the first electrode tab (10a) and the second electrode tab (10b) are each electrically connected to the two electrode terminals (30). The two electrode terminals (30) are the first electrode lead-out (7a) and the second electrode lead-out (7b), respectively.

[0495] Optionally, the cylindrical battery cell (7) includes a first current collecting member (40) and a second current collecting member (60), wherein the first current collecting member (40) connects a first electrode tab (10a) and one electrode terminal (30), and the second current collecting member (60) connects a second electrode tab (10b) and another electrode terminal (30).

[0496] In some other embodiments, the cylindrical battery cell includes one electrode terminal installed on the end wall, the first electrode tab is electrically connected to the electrode terminal, and the second electrode tab is electrically connected to the end wall.

[0497] In some embodiments, the projection of the first electrode tab (10a) along the axial direction (Z) is fan-shaped.

[0498] In some embodiments, the projection of the second electrode tab (10b) along the axial direction (Z) is fan-shaped.

[0499] FIG. 25 is a partial schematic cross-sectional view of a cylindrical battery cell provided in some other embodiments of the present application.

[0500] Referring to FIG. 25, in some embodiments, a convex portion (2121) protruding inward is installed on the side wall (212).

[0501] For example, the convex portion (2121) may be a solid structure or a hollow structure.

[0502] In some embodiments, in the axial direction (Z), the convex portion (2121) is located at least partially between the end cover (22) and the second electrode tab (10b).

[0503] Since the convex portion (2121) overlaps with the second electrode tab (10b) in the axial direction (Z), this can limit the movement of the second electrode tab (10b) along the axial direction (Z) when the cylindrical battery cell (7) receives an external impact, thereby reducing the risk of the connection between the second electrode tab (10b) and the second current collector (60) being lost.

[0504] In some embodiments, the second current collector (60) is connected to the convex portion (2121). For example, the second current collector (60) may be welded to the convex portion (2121); alternatively, the second current collector (60) may be press-connected to the convex portion (2121).

[0505] For example, the second current collector (60) may be connected to one side of the convex portion (2121) facing the second electrode tab (10b) and may also be connected to one side of the convex portion (2121) facing the end cover (22).

[0506] By connecting the second current collector member (60) to the convex portion (2121), the conductive path between the second electrode tab (10b) and the end wall (211) is shortened, and the resistance is reduced, thereby reducing heat generation and improving the circulation performance of the cylindrical battery cell (7).

[0507] In some embodiments, a portion of the second current collector (60) is located on one side of the convex portion (2121) facing the end cover (22) and is connected to the convex portion (2121). Since the second current collector (60) is connected to the convex portion (2121) from the outside of the convex portion (2121), the difficulty of assembly can be reduced.

[0508] In some embodiments, the second current collector (60) is welded to the convex portion (2121).

[0509] In some embodiments, a concave portion (2122) is installed on the outer side of the side wall (212), and the positions of the concave portion (2122) and the convex portion (2121) correspond. For example, after mounting the electrode assembly (10) inside the housing body (21), the side wall (212) is compressed from the outside to form a convex portion (2121) protruding inward.

[0510] In some embodiments, the side wall (212) also includes a compression portion (2123), and the compression portion (2123) is installed to extend from one end of a convex portion (2121) away from the end wall (211) and surround the end cover (22).

[0511] A portion of the compression portion (2123) is installed in a bent manner to form a flange structure, and in the axial direction (Z), a portion of the end cover (22) is located between the flange structure and the convex portion (2121). By positioning the end cover (22) with the convex portion (2121) and the flange structure, the end cover (22) can be secured in the axial direction (Z).

[0512] In some embodiments, the cylindrical battery cell (7) also includes an insulating member (70), and the insulating member (70) is installed between the side wall (212) and the end cover (22) to insulate the end cover (22) from the side wall (212).

[0513] In some embodiments, a portion of the insulating member (70) is located between the second current collector (60) and the end cover (22) to insulate the second current collector (60) from the end cover (22).

[0514] According to some embodiments of the present application, the present application also provides a battery comprising a plurality of cylindrical battery cells (7) according to any one embodiment.

[0515] According to some embodiments of the present application, the present application also provides an electric device comprising a cylindrical battery cell (7) according to any one embodiment above, wherein the cylindrical battery cell (7) is used to provide electric energy to the electric device. The electric device may be a device or system utilizing any one of the aforementioned cylindrical battery cells (7).

[0516] Referring to FIGS. 4 through 9, an embodiment of the present application provides a cylindrical battery cell (7), which includes a housing (20), an electrode assembly (10), an electrode terminal (30), a first current collector (40), and a second current collector (60).

[0517] The housing (20) includes a housing body (21) and an end cover (22), the housing body (21) includes a side wall (212) and an end wall (211) formed integrally, the end wall (211) and the end cover (22) face each other along the axial direction (Z) of the cylindrical battery cell, and the end cover (22) is welded to the side wall (212).

[0518] The electrode terminal (30) is installed insulated from the end wall (211).

[0519] At least a portion of the electrode assembly (10) is accommodated within the housing (20). The electrode assembly (10) includes an anode (11), a cathode (12), and a separating member (13), and the anode (11), the cathode (12), and the separating member (13) are installed to be wound, and the separating member (13) separates the anode (11) and the cathode (12).

[0520] A first electrode tab (10a) is provided at one end of the positive electrode (11) facing the end wall (211), and a first current collecting member (40) connects the electrode terminal (30) and the first electrode tab (10a). A second electrode tab (10b) is provided at one end of the negative electrode (12) facing the end cover (22), and a second current collecting member (60) connects the first electrode tab (10a) and the end cover (22).

[0521] The separating member (13) comprises a base membrane (13a) and a coating layer (13b) installed on at least one surface of the base membrane (13a). The coating layer (13b) comprises an inorganic particle layer (P3) and a plurality of organic particles (P), wherein the organic particles (P) protrude at least partially from the inorganic particle layer (P3), and the organic particles (P) are used to support the anode (11) or the cathode (12) to form a gap (G) between the anode (11) and the cathode (12).

[0522] Examples

[0523] The following examples provide a more detailed explanation of the disclosed embodiments of this application. Since it is obvious to those skilled in the art that various modifications and changes are possible within the scope of the disclosed embodiments of this application, these examples are used for illustrative purposes only. Unless otherwise noted, all parts, percentages, and ratios reported in the following examples are based on mass. All reagents used in the examples are commercially available or synthesized according to general methods and can be used directly without further processing. All equipment used in the examples is commercially available.

[0524] Example 1

[0525] 1. Manufacture of the anode section

[0526] The positive plate comprises a positive current collector and a positive film layer, the positive film layer is located on both sides of the positive current collector, the positive current collector is aluminum foil, and the positive film layer is a film layer formed by uniformly coating a positive slurry (solvent is N-methylpyrrolidone (NMP)) on the surface of the positive current collector aluminum foil, followed by drying and cold pressing, and the positive film layer comprises a positive active material, a conductor carbon black (Super P), and an adhesive polyvinylidene fluoride (PVDF) in a weight ratio of 97:1:2.

[0527] The positive active material has the molecular formula LiNi 0.8 Co 0.1 Mn 0.1 It includes layered transition metal oxide, O2(NCM811).

[0528] 2. Manufacture of cathode

[0529] The cathode plate comprises a cathode current collector and a cathode film layer, the cathode film layer is located on both sides of the cathode current collector, the cathode current collector is a copper foil, the cathode film layer is a film layer formed by uniformly coating a cathode slurry (solvent is deionized water) on the surface of the copper foil of the cathode current collector, followed by drying and cold pressing, and the cathode film layer comprises a silicon-based material (specifically a silicon-oxygen compound) with a weight ratio of 12.6:82.4:1.9:0.1:3, graphite, conductive carbon black, conductive carbon nanotubes, and adhesive polyacrylic acid.

[0530] The areal density of the cathode film layer is 9.0 mg / cm² 2 The porosity is 22.1%, and the compressive density is 1.7 g / cm³ 3 am.

[0531] 3. Separating member

[0532] A PE (polyethylene) base membrane was provided.

[0533] Preparation of coating layer slurry: Inorganic particles aluminum trioxide (Al2O3), first organic particles vinylidene fluoride-hexafluoropropylene copolymer (number average molecular weight 550,000), second organic particles styrene-vinyl acetate-pyrrolidone copolymer (number average molecular weight 80,000), dispersant sodium carboxymethylcellulose (CMC-Na), and wetting agent organosilicon modified polyether were uniformly mixed in an appropriate amount of solvent deionized water in a dry weight ratio of 70:20:8:1:1 to obtain a coating layer slurry having a solid content of 38% (by weight). Here, the volume average particle size Dv50 of the inorganic particles aluminum trioxide (Al2O3) is 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.

[0534] After coating a coating layer slurry onto two surfaces of a PE base membrane, a separation member was obtained through processes such as drying and slitting.

[0535] 4. Preparation of Electrolyte

[0536] The electrolyte comprises an organic solvent and a lithium salt, and an organic solvent was obtained by mixing ethylene carbonate (EC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC) in a volume ratio of 1:1:1, and then a sufficiently dried lithium salt LiPF6 was dissolved in the mixed organic solvent to prepare an electrolyte with a lithium salt concentration of 1 mol / L.

[0537] 5. Manufacturing of cylindrical battery cells

[0538] An electrode assembly was obtained by sequentially stacking the aforementioned positive electrode, separator, and negative electrode so that a separator is positioned between the positive electrode and the negative electrode to perform a separating function, and then winding the positive electrode, separator, and negative electrode; the electrode assembly was placed in a cylindrical housing, dried, and then an electrolyte was injected, and a cylindrical battery cell was obtained by undergoing processes such as vacuum packaging, settling, forming, and molding, wherein the electrode assembly has a cylindrical structure and the housing has a cylindrical structure, and the housing includes a housing body and an end cover, and the housing body includes a side wall and an end wall formed integrally, the side wall is installed to surround the electrode assembly, and the end cover and the end wall face each other along the axial direction of the housing. The diameter of the cylindrical battery cell is 46 mm and the height is 95 mm.

[0539] Performance test

[0540] 1. Battery cell expansion volume test

[0541] A cylindrical battery cell with 0% charge was immersed in silicone oil, and its mass was measured and indicated as m0.

[0542] A cylindrical battery cell in a 100% charged state was immersed in silicone oil, and its mass was measured and denoted as m1.

[0543] The density of silicone oil is ρ 실리콘 오일 In this case, the volume change ΔV of the cylindrical battery cell at 100% charge and 0% charge is: ΔV=(m0-m1) / ρ 실리콘 오일 And, when evaluating the reliability of use of a cylindrical battery cell with ΔV, the smaller the ΔV, the smaller the volume expansion of the cylindrical battery cell and the higher the reliability of use; the larger the ΔV, the larger the volume expansion of the cylindrical battery cell and the lower the reliability of use.

[0544] Here, at 25°C, the above-described cylindrical battery cell is discharged to 2.5V at 0.33C and then discharged to 2.5V at 0.1C, at which time the cylindrical battery cell is in a 0% charged state. At 25°C, the cylindrical battery cell is charged to 4.25V at 0.33C and then charged to 4.25V at 0.1C, at which time the cylindrical battery cell is in a 100% charged state.

[0545] 2. Energy Density Test of Cylindrical Battery Cells

[0546] At a constant voltage (4.25V in Example 1), it is the ratio of the mass of the cylindrical battery cell to the value obtained by multiplying the primary circulating discharge capacity by the discharge voltage.

[0547] Energy density = primary cyclic discharge capacity (Ah) × discharge voltage (4.25V) / mass of cylindrical battery cell (kg). The primary cyclic discharge capacity was tested according to the following steps: at 45°C, the cylindrical battery cell manufactured as described above was fully charged to 1C and then fully discharged again to 1C, which constitutes one charge-discharge cycle, and the discharge capacity at this time was recorded and set as the primary cyclic discharge capacity.

[0548] 3. Battery cycling performance test

[0549] At 45°C, the cylindrical battery cell manufactured as described above was fully charged to 1C and then fully discharged again to 1C; this constitutes one charge-discharge cycle process, and the discharge capacity at this time was recorded and set as the first cycle discharge capacity. A cycle charge-discharge test was performed on the cylindrical battery cell according to the method described above, and the discharge capacity after each cycle was recorded until the discharge capacity of the cylindrical battery cell decayed to 80% of the initial discharge capacity, and the cycle performance of the cylindrical battery cell was characterized by the number of cycles at this time. The higher the number of cycles of the cylindrical battery cell, the better the cycle performance.

[0550] Examples 2~5

[0551] A battery cell was manufactured using a method similar to that of Example 1, and the difference from Example 1 is that the method for manufacturing the negative electrode in Examples 2 to 5 includes the following steps:

[0552] The cathode plate comprises a cathode current collector and a cathode film layer, the cathode film layer is located on both sides of the cathode current collector, the cathode current collector is a copper foil, the cathode film layer is a film layer formed by uniformly coating a cathode slurry (solvent is deionized water) on the surface of the copper foil cathode current collector, followed by drying and cold pressing, and the cathode film layer comprises a silicon-based material (specifically, a silicon-oxygen compound), graphite, a conductive carbon black, a conductive carbon nanotube, and an adhesive polyacrylic acid; additionally, the mass content and capacitance density of the silicon element were adjusted.

[0553] Examples 6~9

[0554] Battery cells were manufactured using a method similar to Example 1, and the difference from Example 1 is that in Examples 6 to 9, the thickness of the sidewalls was adjusted.

[0555] The test results of each example are as shown in Table 1.

[0556] item cathode film layer Housing Battery cell performance Mass content of silicon element / % Capacity density / (mAh / cm²) 2 ) side wall 45℃ cycle count Energy density (Wh / kg) Expansion volume / mL texture thickness Example 1 2% 3.33 Still 0.50mm 1800 234 0.17 Example 2 6% 3.96 Still 0.50mm 1500 242 0.22 Example 3 8% 4.14 Still 0.50mm 1400 245 0.28 Example 4 13% 4.86 Still 0.50mm 1000 265 0.34 Example 5 19% 5.76 Still 0.50mm 800 294 0.46 Example 6 8% 4.14 Still 0.30mm 1250 257 0.30 Example 7 8% 4.14 Still 0.40mm 1350 249 0.29 Example 8 8% 4.14 Still 0.55mm 1510 242 0.25 Example 9 8% 4.14 Still 0.60mm 1540 236 0.22

[0557] Referring to Table 1, the energy density of a cylindrical battery cell can be significantly improved by introducing silicon into the negative electrode active material. By installing organic particles in the separator, a gap can be formed between the positive electrode and the negative electrode, and the gap can provide space for the expansion of the negative electrode. Referring to Table 1, when the expansion volume of the cylindrical battery cell is 0.5 mL or less and the number of cycles of the cylindrical battery cell is 800 or more, the cylindrical battery cell has relatively excellent reliability and cycle performance.

[0558] Referring to Examples 1 to 5, by adjusting the mass content of silicon elements, the capacity areal density can be adjusted synchronously, which is advantageous for improving both the cycling performance and energy density of the battery cell. The gap can provide space for the expansion of the negative electrode, and when the silicon element content reaches 19%, the expansion volume of the cylindrical battery cell is 0.5 mL or less, and the number of cycles of the cylindrical battery cell is 800 or more.

[0559] Referring to Examples 1 and 6 to 9, by adjusting the sidewall thickness and mixing with the mass content of silicon elements, it is advantageous to reduce the volume expansion of the battery cell relatively while improving both the circulation performance and energy density of the battery cell. Since the steel sidewall has relatively high mechanical strength, it can effectively improve the volume expansion problem and improve both the circulation performance and energy density of the battery cell.

[0560] It should be explained that the embodiments and features of the embodiments of the present application may be combined with one another insofar as there is no conflict.

[0561] Finally, it must be noted that the above embodiments are used merely to illustrate the technical solution of the present application and are not intended to limit it; although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art may still modify the technical solution described in each of the above embodiments or replace some of the technical features therein with equivalents, provided that such modification or replacement does not cause the essence of the corresponding technical solution to deviate from the spirit and scope of the technical solution of each embodiment of the present application. Explanation of the symbols

[0562] 1: Vehicle; 2: Battery; 3: Controller; 4: Motor; 5: Case; 5a: First case section; 5b: Second case section; 5c: Accommodation space; 6: Battery module; 7: Cylindrical battery cell; 7a: First electrode lead-out section; 7b: Second electrode lead-out section; 10: Electrode assembly; 10a: First electrode tab; 10b: Second electrode tab; 10c: Electrode body; 10d: Center hole; 11: Anode piece; 111: Anode base portion; 112: Anode protrusion; 113: Anode recess; 11a: Anode current collector; 11b: Anode film layer; 11c: Anode particle coating layer; 12: Cathode piece; 121: Cathode base portion; 122: Cathode protrusion; 123: Cathode recess; 12a: Cathode current collector; 12b: Cathode film layer; 12c: Cathode particle coating layer; 13: Separating member; 131: Separating base portion; 13a: Base film; 13b: Coating layer; 14: Support section; 141: First support section; 142: Second support section; 15: Base part; 151: First surface; 20: Housing; 21: Housing body; 211: End wall; 212: Side wall; 2121: Convex portion; 2122: Concave portion; 2123: Compression portion; 22: End cover; 30: Electrode terminal; 31: Terminal recess; 32: Through-hole; 40: First current collector; 50: Cover plate; 60: Second current collector; 70: Insulating member; G: Gap; G1: 1st Gap; G2: 2nd Gap; C1: Middle region; C2: End region; C3: Transition region; E1: Winding start section; E2: Winding end section; E3: Positive winding start section; E4: Positive winding end section; E5: Negative winding start section; E6: Negative winding end section; E7: 1st section; E8: 2nd section; S: Intermediate section; P: Organic particle; P1: First organic particle; P2: Second organic particle; P3: Inorganic particle layer; V: Winding direction; Z: Axial direction.

Claims

Claim 1 A cylindrical battery cell having a diameter ≥40 mm, comprising: a housing; an electrode assembly in which at least a portion thereof is accommodated within the housing, wherein the electrode assembly comprises a positive electrode, a negative electrode, and a separator, wherein the positive electrode, the negative electrode, and the separator are installed to be wound, wherein the separator separates the positive electrode and the negative electrode, and wherein the negative active material of the negative electrode comprises at least one of a silicon-based material and a carbon-based material; wherein at least one of the positive electrode, the negative electrode, and the separator comprises a base portion and a plurality of support portions, wherein the base portion has two first surfaces installed oppositely along its own thickness direction, and the plurality of support portions are installed to protrude from at least one of the first surfaces to form a gap between the positive electrode and the negative electrode. Claim 2 A cylindrical battery cell according to claim 1, wherein the support member is configured to be compressible. Claim 3 A cylindrical battery cell according to claim 1 or 2, wherein the plurality of support members includes a first support member and a second support member, and on the same side of the base member, the height of the first support member protruding from the first surface is greater than the height of the second support member protruding from the first surface. Claim 4 A cylindrical battery cell according to paragraph 3, wherein at least one of the positive electrode, the negative electrode, and the separating member comprises a plurality of organic particles, and the support member comprises the organic particles. Claim 5 A cylindrical battery cell according to claim 4, wherein the plurality of organic particles comprises a first organic particle and a second organic particle, and the number average particle size of the first organic particle is larger than the number average particle size of the second organic particle. Claim 6 A cylindrical battery cell according to claim 4 or 5, wherein the plurality of supports includes a first support and a second support, and on the same side of the base, the height of the first support protruding from the first surface is greater than the height of the second support protruding from the first surface; the plurality of organic particles includes a first organic particle and a second organic particle; and the first support includes the first organic particle, and the second support includes the second organic particle. Claim 7 In any one of claims 4 to 6, the plurality of organic particles comprises a first organic particle, wherein the first organic particle comprises one or more of a homopolymer or copolymer of fluorine-containing 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 alkylene oxide monomer units, and a modification compound of each of the above-described homopolymer or copolymer; optionally, the first organic particle comprises polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinyl fluoride, polyvinylidene fluoride, polyethylene, polypropylene, polyacrylonitrile, polyethylene oxide, a copolymer of different fluorine-containing alkenyl monomer units, a copolymer of fluorine-containing alkenyl monomer units and olefin monomer units, and a copolymer of fluorine-containing alkenyl monomer units and acrylic acid monomer units. A cylindrical battery cell comprising one or more of a copolymer, a copolymer of a fluorine-containing alkenyl monomer unit and an acrylate monomer unit, and a modified compound of each of the above-described homopolymer or copolymer. Claim 8 In any one of claims 4 to 7, the plurality of organic particles comprises a second organic particle, wherein the second organic particle comprises one or more of an acrylate-based monomer unit homopolymer or copolymer, an acrylic acid-based monomer unit homopolymer or copolymer, a styrene-based monomer unit homopolymer or copolymer, a polyurethane-based compound, a rubber-based compound, and a modified compound of each of the above-mentioned homopolymers or copolymers; optionally, the second organic particle comprises a copolymer of an acrylate-based monomer unit and a styrene-based monomer unit, a copolymer of an acrylic acid-based monomer unit and a styrene-based monomer unit, a copolymer of an acrylic acid-based monomer unit-acrylate-based monomer unit-styrene-based monomer unit, a copolymer of a styrene-based monomer unit and an unsaturated nitrile-based monomer unit, or a copolymer of a styrene-based monomer unit-olefin monomer unit-unsaturated nitrile-based monomer unit. A cylindrical battery cell comprising a copolymer of monomer units and one or more of the modified compounds of the copolymer described above. Claim 9 A cylindrical battery cell according to any one of claims 1 to 8, wherein the housing comprises a side wall installed to surround the electrode assembly, the material of the side wall comprises steel, and the thickness of the side wall is 0.3 mm to 1.5 mm, optionally 0.3 mm to 1.2 mm. Claim 10 A cylindrical battery cell according to any one of claims 1 to 9, wherein the cathode piece comprises a cathode current collector and a cathode film layer installed on at least one side of the cathode current collector and containing the cathode active material, wherein the cathode active material comprises a silicon-based material; and wherein the mass content of silicon elements of the silicon-based material in the cathode film layer is 2% to 19%, optionally 6% to 13%. Claim 11 In any one of claims 1 to 10, the capacity areal density of the cathode is 3.2 mAh / cm² 2 Lee Sang-in, cylindrical battery cell. Claim 12 In claim 11, the capacitance areal density of the cathode is 3.3 mAh / cm² 2 Up to 11.5mAh / cm 2 Phosphorus, cylindrical battery cell. Claim 13 In claim 12, the capacity areal density of the cathode is 3.96 mAh / cm² 2 Up to 7.56mAh / cm² 2 Phosphorus, cylindrical battery cell. Claim 14 A cylindrical battery cell according to any one of claims 1 to 13, wherein the gap is installed in two places, and the two gaps are each installed on both sides of the positive plate. Claim 15 A cylindrical battery cell according to any one of claims 1 to 14, wherein, wherein at least some of the radial size of the gap is 5 μm to 60 μm. Claim 16 A cylindrical battery cell according to any one of claims 1 to 15, wherein the gap extends along the winding direction of the electrode assembly and the gap has a winding start end and a winding end. Claim 17 A cylindrical battery cell according to claim 16, wherein the radial size of the portion near the end of the winding in the gap is larger than the radial size of the portion near the beginning of the winding in the gap. Claim 18 A cylindrical battery cell according to claim 16 or 17, wherein the gap is wound along the winding direction to form n winding turns, n≥20 and n is a natural number; the innermost winding turn is the first winding turn; the radial size of the k-th winding turn is smaller than the radial size of the k+10th winding turn, k is a natural number, and 5≤k≤n-15. Claim 19 A cylindrical battery cell according to any one of claims 16 to 18, wherein the gap is wound along the winding direction to form n winding turns, n≥20 and n is a natural number; the innermost winding turn is the first winding turn; and the average value of the radial size of the n-9th to n-5th winding turns is greater than the average value of the radial size of the 5th to 9th winding turns. Claim 20 A cylindrical battery cell according to any one of claims 1 to 19, wherein the electrode assembly comprises a middle region and two end regions arranged along the axial direction of the cylindrical battery cell, the middle region being located between the two end regions; and the radial size of the portion installed in the middle region in the gap being smaller than the radial size of the portion installed in the end regions in the gap. Claim 21 A cylindrical battery cell according to claim 20, wherein, in a direction in which each of the two end regions faces the middle region, the radial size of the gaps both show a decreasing trend. Claim 22 A cylindrical battery cell according to any one of claims 1 to 21, wherein the separating member comprises the base portion and a plurality of the support portions, and the support portions comprise organic particles installed on the base portion. Claim 23 In claim 22, the base portion of the separating member comprises a base membrane and an inorganic particle layer installed on the base membrane, and the organic particles protrude at least partially from the inorganic particle layer, a cylindrical battery cell. Claim 24 In any one of claims 1 to 23, wherein, a plurality of the support members are installed on one side of the positive member facing the separating member, and a plurality of the support members are installed on one side of the separating member facing the positive member, and the plurality of the support members of the positive member facing the separating member are installed at least partially opposite to the plurality of the support members of the separating member facing the positive member; and / or, a plurality of the support members are installed on one side of the negative member facing the separating member, and a plurality of the support members are installed on one side of the separating member facing the negative member, and the plurality of the support members of the negative member facing the separating member are installed at least partially opposite to the support members of the separating member facing the plurality of negative members; and / or, a plurality of the support members are installed on one side of the cathode member facing the positive member, and a plurality of the support members are installed on one side of the positive member facing the negative member, and the plurality of the support members of the cathode member facing the positive member are installed opposite to at least a portion of the plurality of support members of the positive member facing the negative member. Claim 25 A cylindrical battery cell according to any one of claims 1 to 24, wherein a plurality of the support members are installed on both sides of the separating member. Claim 26 A cylindrical battery cell according to any one of claims 1 to 25, wherein the gap comprises a first gap and a second gap, the first gap being formed between the positive electrode and the separating member, and the second gap being formed between the negative electrode and the separating member. Claim 27 A cylindrical battery cell according to any one of claims 1 to 26, wherein a positive recess is installed on one side of the positive plate facing the separating member. Claim 28 A cylindrical battery cell according to claim 27, wherein the positive plate comprises a positive film layer and the positive indentation is formed in the positive film layer. Claim 29 In claim 28, the cylindrical battery cell, wherein the positive concave portion penetrates the positive film layer along the axial direction of the cylindrical battery cell. Claim 30 A cylindrical battery cell according to any one of claims 27 to 29, wherein the positive recesses are plurality; and at least some of the plurality of positive recesses are installed on the inner side of the positive piece. Claim 31 A cylindrical battery cell according to any one of claims 27 to 30, wherein the positive plate comprises a plurality of positive plate recesses spaced apart along the winding direction. Claim 32 A cylindrical battery cell according to any one of claims 1 to 31, wherein a negative electrode recess is installed on one side of the negative electrode piece facing the separating member. Claim 33 A cylindrical battery cell according to claim 32, wherein the cathode portion comprises a cathode film layer, and the cathode concave portion is formed in the cathode film layer. Claim 34 In paragraph 33, the cylindrical battery cell, wherein the negative electrode recess penetrates the negative electrode film layer along the axial direction of the cylindrical battery cell. Claim 35 A cylindrical battery cell according to any one of claims 32 to 34, wherein the cathode recesses are plurality; and at least some of the plurality of cathode recesses are installed on the inner side of the cathode piece. Claim 36 A cylindrical battery cell according to any one of claims 32 to 35, wherein the cathode piece comprises a plurality of cathode recesses spaced apart along the winding direction. Claim 37 A cylindrical battery cell according to any one of claims 1 to 36, wherein one of the positive electrode and the negative electrode comprises a first electrode tab and the other comprises a second electrode tab; wherein the cylindrical battery cell comprises a first electrode lead and a second electrode lead, wherein the first electrode lead is electrically connected to the first electrode tab and the second electrode lead is electrically connected to the second electrode tab; and wherein, in 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. Claim 38 A cylindrical battery cell according to any one of claims 1 to 37, wherein the housing comprises a housing body and an end cover, the housing body comprises a side wall and an end wall, the side wall surrounds the electrode assembly, the end wall and the end cover face each other along the axial direction of the cylindrical battery cell, and the end cover is sealedly connected to the side wall. Claim 39 In claim 38, one of the positive electrode and the negative electrode comprises a first electrode tab and the other comprises a second electrode tab; the cylindrical battery cell also comprises an electrode terminal installed insulatedly on the end wall, wherein one of the first electrode tab and the second electrode tab is electrically connected to the electrode terminal and the other is electrically connected to the end wall. Claim 40 In claim 39, the cylindrical battery cell further comprises a first current collector, wherein the first current collector is located on one side of the first electrode tab facing the end wall and is connected to the first electrode tab; and the electrode terminal is connected to the surface of the first current collector facing the end wall. Claim 41 A cylindrical battery cell according to claim 40, wherein a terminal recess is installed on one side of the electrode terminal facing the first current collecting member, and / or, a terminal recess is installed on one side of the electrode terminal away from the first current collecting member; and the lower wall of the terminal recess is welded to the first current collecting member. Claim 42 A cylindrical battery cell according to any one of claims 39 to 41, wherein the first electrode tab and the second electrode tab are both located at one end of the electrode assembly facing the end wall. Claim 43 In any one of claims 39 to 41, the first electrode tab is located at one end of the electrode assembly facing the end wall, and the second electrode tab is located at one end of the electrode assembly facing the end cover; the cylindrical battery cell also includes a second current collector connected to the second electrode tab; and the second current collector is connected to at least one of the end cover and the side wall, the cylindrical battery cell. Claim 44 A cylindrical battery cell according to any one of claims 1 to 43, wherein the height of the housing is 1.3 to 4 times the diameter of the housing. Claim 45 A cylindrical battery cell according to any one of claims 1 to 44, wherein the height of the housing is 50 mm to 150 mm; and / or the diameter of the housing is 45 mm to 80 mm. Claim 46 A battery comprising a cylindrical battery cell according to any one of claims 1 to 45. Claim 47 An electric device comprising a battery according to paragraph 46, said battery being used to provide electrical energy.

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