Cylindrical battery cell, battery and electrical device

Abstract

Provided in the embodiments of the present application are a cylindrical battery cell, a battery and an electrical device. The cylindrical battery cell comprises a casing and an electrode assembly. The diameter of the cylindrical battery cell is greater than or equal to 40 mm. At least part of the electrode assembly is accommodated in the casing. The electrode assembly comprises a positive electrode sheet, a negative electrode sheet and a separator, wherein the positive electrode sheet, the negative electrode sheet and the separator are wound, and the separator separates the positive electrode sheet from the negative electrode sheet. A negative electrode active material of the negative electrode sheet comprises at least one of silicon and carbon. At least one of the positive electrode sheet, the negative electrode sheet and the separator comprises a base portion and a plurality of support portions arranged on the base portion. The base portion has two first surfaces disposed opposite each other in the direction of thickness of the base portion. The plurality of support portions protrude from at least one of the first surfaces to form a gap between the positive electrode sheet and the negative electrode sheet.

Description

Cylindrical battery cells, batteries and electrical devices

[0001] Cross-references to related applications

[0002] This application claims priority to international patent application PCT / CN2024 / 100930, filed on June 24, 2024, entitled “Cylindrical Battery Cell, Battery and Electrical Device”, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the field of battery technology, and more specifically, to a cylindrical battery cell, a battery, and an electrical device. Background Technology

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

[0005] As the demand for energy density increases, the diameter of cylindrical battery cells is gradually increasing. However, with the increase in the diameter of cylindrical battery cells, the expansion force during cycling also increases, and this expansion force affects the cycle performance of the cylindrical battery cells. How to improve the cycle performance of large-diameter cylindrical battery cells is an important research direction in the field of battery technology. Summary of the Invention

[0006] This application provides a cylindrical battery cell, a battery, and an electrical device that improves reliability.

[0007] In a first aspect, embodiments of this application provide a cylindrical battery cell with a diameter ≥ 40 mm, including a casing and an electrode assembly. At least a portion of the electrode assembly is housed within the casing. The electrode assembly includes a positive electrode, a negative electrode, and a separator, which are wound together, with the separator separating the positive and negative electrodes. The negative electrode active material of the negative electrode includes at least one of silicon-based and carbon-based materials. At least one of the positive electrode, negative electrode, and separator includes a base and a plurality of support portions disposed on the base. The base has two first surfaces disposed opposite each other along its thickness direction. The plurality of support portions protrude from at least one first surface to form a gap between the positive and negative electrodes.

[0008] Multiple protruding support portions support at least one of the positive and negative electrode plates, creating a gap between them. During cycling of the cylindrical battery cell, this gap provides space for the expansion of the negative electrode plate, reducing the compression of the electrolyte within the internal pores of the positive and negative electrode films. This reduces electrolyte concentration differences across regions within the electrode and improves the cycling performance of cylindrical battery cells with larger diameters. The gap also reduces the expansion of the electrode assembly, minimizing the compression on the casing, lowering the risk of casing deformation and cracking, and improving the reliability of the cylindrical battery cell. By incorporating the gap, the increase in expansion force caused by increasing the diameter of the cylindrical battery cell can be reduced, thereby increasing the capacity of the cylindrical battery cell.

[0009] In some embodiments, the support portion is configured to be compressible. During the cycling of the cylindrical battery cell, the support portion can be compressed under pressure, thereby providing more expansion space for the negative electrode. The compressible support portion can release stress through compression deformation, reducing the risk of damage to the positive or negative electrode by the support portion and improving reliability.

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

[0011] The first support section has a relatively large height, which can support either the positive or negative electrode sheet to create a larger gap, thus providing more space for the expansion of the negative electrode sheet. The second support section is smaller in height and occupies less space. As the negative electrode sheet expands, the gap gradually decreases; the second support section can be compressed only after the negative electrode sheet has expanded to a certain extent, thus reducing the pressure on the negative electrode sheet in the initial stage of expansion. When the second support section is compressed, it can slow down the expansion of the negative electrode sheet to a certain extent, reducing the electrolyte squeezed out by the negative electrode sheet and improving the cycle performance of the cylindrical battery cell.

[0012] In some embodiments, at least one of the positive electrode, negative electrode, and separator includes a plurality of organic particles, and the support portion includes organic particles. The organic particles can act as a support to form gaps. In the event of thermal runaway in a cylindrical battery cell, the organic particles can form a gel film structure at high temperatures, thereby reducing the diffusion channels of active ions, delaying the time of heat propagation, and thus improving the reliability of the cylindrical battery cell.

[0013] In some embodiments, the plurality of organic particles includes first organic particles and second organic particles, wherein the number average particle size of the first organic particles is larger than that of the second organic particles. The first organic particles with a larger number average particle size can support the positive or negative electrode sheet to form a larger gap, thereby providing more space for the expansion of the negative electrode sheet. The second organic particles with a smaller number average particle size can be compressed after the negative electrode sheet has expanded to a certain extent, thus reducing the pressure on the negative electrode sheet during the initial expansion phase. When the second organic particles are compressed, they can, to some extent, slow down the expansion of the negative electrode sheet, reduce the electrolyte squeezed out by the negative electrode sheet, and improve the cycle performance of the cylindrical battery cell.

[0014] In some embodiments, the plurality of support portions include a first support portion and a second support portion, wherein on the same side of the base, the first support portion protrudes from the first surface at a greater height than the second support portion protrudes from the first surface. The plurality of organic particles include first organic particles and second organic particles; the first support portion includes the first organic particles, and the second support portion includes the second organic particles.

[0015] By incorporating first and second organic particles with different number-average particle sizes, first and second support portions with different heights can be formed. The first support portion has a greater height, which can support either the positive or negative electrode sheet to create a larger gap, thereby providing more space for the expansion of the negative electrode sheet. The second support portion can be compressed only after the negative electrode sheet has expanded to a certain extent, thus reducing the pressure on the negative electrode sheet in the initial stage of expansion. When the second support portion is compressed, it can slow down the expansion of the negative electrode sheet to a certain extent, reducing the electrolyte squeezed out by the negative electrode sheet and improving the cycle performance of the cylindrical battery cell.

[0016] In some embodiments, the plurality of organic particles include a first organic particle, the first organic particle comprising one or more of the following: a homopolymer or copolymer of fluorinated alkenyl monomer units, a homopolymer or copolymer of olefinic monomer units, a homopolymer or copolymer of unsaturated nitrile monomer units, a homopolymer or copolymer of epoxide monomer units, and a modified compound of the above homopolymers or copolymers.

[0017] In some embodiments, the first organic particle includes one or more of the following: polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinylidene fluoride, polyvinylidene fluoride, polyethylene, polypropylene, polyacrylonitrile, polyethylene oxide, copolymers of different fluorinated alkenyl monomer units, copolymers of fluorinated alkenyl monomer units and olefin monomer units, copolymers of fluorinated alkenyl monomer units and acrylic monomer units, copolymers of fluorinated alkenyl monomer units and acrylate monomer units, and modified compounds of the above homopolymers or copolymers.

[0018] In some embodiments, the plurality of organic particles include second organic particles, which include one or more of the following: homopolymers or copolymers of acrylate monomer units, homopolymers or copolymers of acrylate monomer units, homopolymers or copolymers of styrene monomer units, polyurethane compounds, rubber compounds, and modified compounds of the above homopolymers or copolymers.

[0019] In some embodiments, the second organic particle comprises one or more of the following: a copolymer of acrylate monomer units and styrene monomer units, a copolymer of acrylate monomer units and styrene monomer units, a copolymer of acrylate monomer units-acrylate monomer units-styrene monomer units, a copolymer of styrene monomer units and unsaturated nitrile monomer units, a copolymer of styrene monomer units-olefin monomer units-unsaturated nitrile monomer units, and a modified compound of the above copolymers.

[0020] In some embodiments, the housing includes sidewalls surrounding the electrode assembly, the sidewalls having a thickness of 0.3 mm to 1.5 mm, and the sidewalls being made of steel. By providing gaps, this application can reduce the expansion force exerted by the electrode assembly on the sidewalls; therefore, the steel sidewalls can have a thickness of less than or equal to 1.5 mm, thereby increasing the energy density of the cylindrical battery cell. The steel sidewalls having a thickness greater than or equal to 0.3 mm reduces the risk of deformation and cracking of the sidewalls under the expansion force of the electrode assembly, improving the reliability of the cylindrical battery cell.

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

[0022] In some embodiments, the negative electrode includes a negative current collector and a negative electrode film layer disposed on at least one side of the negative current collector and containing a negative electrode active material. The negative electrode active material includes a silicon-based material, wherein the silicon content of the silicon-based material in the negative electrode film layer is 2% to 19% by mass.

[0023] The introduction of silicon-based materials can enhance the capacity of the negative electrode active material and increase the energy density of the cylindrical battery cell; the gaps can provide space for the expansion of the negative electrode sheet, thereby reducing the influence of silicon-based materials on the expansion force. In this application, the mass content of silicon-based materials in the negative electrode film is limited to the above-mentioned range to balance the expansion and capacity of the negative electrode sheet to a certain extent, taking into account both the cycle performance and energy density of the cylindrical battery cell.

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

[0025] In some embodiments, the areal density of the negative electrode is greater than or equal to 3.2 mAh / cm³.2 The embodiments of this application, by setting a gap, can reduce the impact of increasing the areal density of the negative electrode on the expansion force, thereby increasing the capacity of the negative electrode and improving the energy density of the cylindrical battery cell.

[0026] In some embodiments, the areal density of the negative electrode is 3.3 mAh / cm³. 2 Up to 11.5mAh / cm 2 The embodiments of this application can, to a certain extent, balance the capacity and expansion of the negative electrode, while taking into account the energy density and cycle performance of the cylindrical battery cell.

[0027] In some embodiments, the areal density of the negative electrode is 3.96 mAh / cm³. 2 Up to 7.56mAh / cm 2 This can further balance the energy density and cycle performance of cylindrical battery cells.

[0028] In some embodiments, two gaps are provided, one on each side of the positive electrode sheet. By providing two gaps, the expansion of the electrode assembly can be further reduced, thereby reducing the squeezing effect on the casing, lowering the risk of casing deformation and cracking, and improving the reliability of the cylindrical battery cell.

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

[0030] In some embodiments, the radial dimension of at least a portion of the gap is 5 μm-60 μm. Limiting the radial dimension W of at least a portion of the gap to greater than or equal to 5 μm provides space for the expansion of the negative electrode, reduces expansion force, improves the cycle performance of the cylindrical battery cell, and reduces the risk of casing deformation and cracking. In this application embodiment, the radial dimension W of at least a portion of the gap is limited to less than or equal to 60 μm to shorten the ion migration path between the positive and negative electrodes, reduce the internal resistance of the cylindrical battery cell, reduce heat generation, and minimize the impact of the gap on energy density.

[0031] In some embodiments, the radial dimension of the portion of the gap near the winding end is greater than the radial dimension of the portion of the gap near the winding start end.

[0032] During the cycling process of a cylindrical battery cell, the expansion of the negative electrode gradually accumulates radially from the inside to the outside. In the embodiments of this application, the portion of the gap near the winding end has a larger radial dimension to provide more expansion space for the negative electrode, absorb the accumulated expansion of the negative electrode, thereby reducing the force between the electrode assembly and the casing, reducing the deformation of the casing, reducing the risk of casing cracking, and improving reliability.

[0033] In some embodiments, the gap is wound along the winding direction to form n winding loops, where n ≥ 20 and n is a natural number. The innermost winding loop is the first winding loop. The radial dimension of the kth winding loop is smaller than the radial dimension of the (k+10th)th winding loop, where k is a natural number and 5 ≤ k ≤ n-15.

[0034] The (k+10)th winding is positioned further outward than the (k)th winding, and the radial dimension of the (k+10)th winding is larger than that of the (k)th winding. The (k+10)th winding can provide more expansion space for the negative electrode film layer of the inner negative electrode sheet, absorb the accumulated expansion of the negative electrode sheet, thereby reducing the interaction force between the electrode assembly and the housing, reducing the deformation of the housing, reducing the risk of housing cracking, and improving reliability.

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

[0036] The portion of the gap near the winding end has a larger radial dimension to provide more expansion space for the negative electrode, absorb the accumulated expansion of the negative electrode, thereby reducing the force between the electrode assembly and the housing, reducing the deformation of the housing 20, reducing the risk of cracking of the housing 20, and improving reliability.

[0037] In some embodiments, the electrode assembly includes a central region and two end regions arranged axially along the cylindrical cell, with the central region located between the two end regions; the radial dimension of the portion of the gap located in the central region is smaller than the radial dimension of the portion of the gap located in the end regions. The gap has a larger radial dimension in the end regions to facilitate the entry of electrolyte into the gap, improve the electrolyte's wetting effect on the electrode, and enhance the cycle performance of the cylindrical cell.

[0038] In some embodiments, the radial dimension of the gap decreases in the direction from the two end regions to the middle region, so as to reduce the abrupt change in the radial dimension of the gap, reduce the stress concentration of the negative electrode, and improve the cycle performance of the battery cell.

[0039] In some embodiments, the separator includes a base and a plurality of support portions, the support portions including organic particles disposed on the base. The organic particles can support the positive or negative electrode to increase the gap and provide space for the expansion of the negative electrode.

[0040] In some embodiments, the base of the separator includes a base film and an inorganic particle layer disposed on the base film, wherein organic particles at least partially protrude from the inorganic particle layer. The inorganic particle layer includes a plurality of inorganic particles, and sufficient and unevenly distributed voids are formed between the inorganic and organic particles, which can improve the air permeability of the separator and enable the cylindrical battery cell to have better cycle performance and reliability.

[0041] In some embodiments, the positive electrode sheet has a plurality of support portions on the side facing the separator, and the separator has a plurality of support portions on the side facing the positive electrode sheet. The plurality of support portions of the positive electrode sheet facing the separator and the plurality of support portions of the separator facing the positive electrode sheet are at least partially opposite to each other. By arranging the plurality of support portions of the positive electrode sheet and the plurality of support portions of the separator facing each other, the plurality of support portions of the positive electrode sheet and the plurality of support portions of the separator can at least partially abut against each other, thereby increasing the gap and providing more space for the expansion of the negative electrode sheet.

[0042] In some embodiments, the negative electrode sheet has a plurality of support portions on the side facing the separator, and the separator has a plurality of support portions on the side facing the negative electrode sheet. The plurality of support portions of the negative electrode sheet facing the separator and the plurality of support portions of the separator facing the negative electrode sheet are at least partially opposite each other. By arranging the plurality of support portions of the negative electrode sheet and the plurality of support portions of the separator facing each other, the support portions of the negative electrode sheet and the support portions of the separator can at least partially abut against each other, thereby increasing the gap and providing more space for the expansion of the negative electrode sheet.

[0043] In some embodiments, the negative electrode sheet has a plurality of support portions on the side facing the positive electrode sheet, and the positive electrode sheet has a plurality of support portions on the side facing the negative electrode sheet. At least a portion of the support portions of the negative electrode sheet facing the positive electrode sheet are arranged opposite to the plurality of support portions of the positive electrode sheet facing the negative electrode sheet. By arranging the plurality of support portions of the negative electrode sheet and the plurality of support portions of the positive electrode sheet facing each other, the support portions of the negative electrode sheet and the support portions of the positive electrode sheet can support each other, thereby increasing the gap and providing more space for the expansion of the negative electrode sheet.

[0044] In some embodiments, multiple support portions are provided on both sides of the separator. By providing multiple support portions on both sides of the separator, the gap can be increased, providing more space for the expansion of the negative electrode sheet.

[0045] In some embodiments, the gap includes a first gap and a second gap, the first gap being formed between the positive electrode and the separator, and the second gap being formed between the negative electrode and the separator. Both the first gap and the second gap can provide space for the expansion of the negative electrode film, thereby reducing the squeezing effect on the casing, reducing the risk of casing deformation and cracking, and improving the reliability of the cylindrical battery cell.

[0046] In some embodiments, the positive electrode sheet has a positive electrode recess on the side facing the separator.

[0047] By incorporating a positive electrode recess, the gap between the positive and negative electrode plates can be increased. During the cycling process of a cylindrical battery cell, the positive electrode recess provides space for the expansion of the negative electrode film, reducing the pressure between the positive and negative electrode plates. This alleviates the compression of the electrolyte within the internal pores of both the positive and negative electrode films, reduces the concentration difference of the electrolyte in different regions within the electrode, and improves the cycle performance of cylindrical battery cells with larger diameters. The positive electrode recess also reduces the expansion of the electrode assembly, thereby reducing the compression effect on the casing, lowering the risk of casing deformation and cracking, and improving the reliability of the cylindrical battery cell.

[0048] In some embodiments, the positive electrode includes a positive electrode film layer, and a positive electrode recess is formed in the positive electrode film layer, which can reduce the impact of the positive electrode recess on the current-carrying capacity of the positive electrode current collector of the positive electrode.

[0049] In some embodiments, the positive electrode recess extends through the positive electrode film layer along the axial direction of the cylindrical battery cell to increase the gap between the positive and negative electrode plates and improve the wettability of the electrolyte.

[0050] In some embodiments, there are multiple positive electrode recesses; at least a portion of the multiple positive electrode recesses are disposed on the inner side of the positive electrode sheet. The inner side of the positive electrode sheet has a large curvature. By disposing the positive electrode recesses on the inner side of the positive electrode sheet, stress can be released, reducing the risk of positive electrode active material in the positive electrode film layer falling off.

[0051] In some embodiments, the positive electrode includes a plurality of positive electrode recesses spaced apart along the winding direction. The plurality of positive electrode recesses can provide space for expansion of different regions of the negative electrode film, reducing the pressure between the positive and negative electrode sheets.

[0052] In some embodiments, a negative electrode recess is provided on the side of the negative electrode sheet facing the insulating member.

[0053] By incorporating a negative electrode recess, the gap between the positive and negative electrode plates can be increased. During the cycling process of a cylindrical battery cell, the negative electrode recess provides space for the expansion of the negative electrode film, reducing the pressure between the positive and negative electrode plates. This alleviates the compression of the electrolyte within the internal pores of both the positive and negative electrode films, reduces the concentration difference of the electrolyte in different regions within the electrode, and improves the cycle performance of cylindrical battery cells with larger diameters. The negative electrode recess also reduces the expansion of the electrode assembly, thereby reducing the compression effect on the casing, lowering the risk of casing deformation and cracking, and improving the reliability of the cylindrical battery cell.

[0054] In some embodiments, the negative electrode sheet includes a negative electrode film layer, and a negative electrode recess is formed in the negative electrode film layer, which can reduce the influence of the negative electrode recess on the flow capacity of the negative electrode current collector of the negative electrode sheet.

[0055] In some embodiments, the negative electrode recess extends through the negative electrode film layer along the axial direction of the cylindrical battery cell to increase the gap between the positive and negative electrode plates and improve the wettability of the electrolyte.

[0056] In some embodiments, there are multiple negative electrode recesses; at least a portion of the multiple negative electrode recesses are disposed on the inner side of the negative electrode sheet. The inner side of the negative electrode sheet has a large curvature. By disposing the negative electrode recesses on the inner side of the negative electrode sheet, stress can be released, reducing the risk of the negative electrode active material in the negative electrode film layer falling off.

[0057] In some embodiments, the negative electrode includes a plurality of negative electrode recesses spaced apart along the winding direction. The plurality of negative electrode recesses can provide space for expansion of different regions of the negative electrode film, reducing the pressure between the positive electrode and the negative electrode.

[0058] In some embodiments, one of the positive and negative electrodes includes a first tab, and the other includes a second tab. A cylindrical battery cell includes a first electrode lead and a second electrode lead, the first electrode lead being electrically connected to the first tab, and the second electrode lead being electrically connected to the second tab. Axially, the first and second electrode leads are located on the same side of the electrode assembly. When multiple cylindrical battery cells are assembled into a group, the first and second electrode leads of the multiple cylindrical battery cells can be arranged on the same side, facilitating the connection between the current collector and the first and second electrode leads, and simplifying the battery structure.

[0059] In some embodiments, the housing includes a casing and an end cap. The casing includes a sidewall and an end wall. The sidewall surrounds the electrode assembly. The end wall and the end cap are axially opposed to each other along the cylindrical cell. The end cap is sealed to the sidewall.

[0060] In some embodiments, the sidewalls and endwalls are integrally formed.

[0061] In some embodiments, one of the positive and negative electrodes includes a first tab, and the other includes a second tab. The cylindrical battery cell also includes an electrode terminal insulated from the end wall. One of the first and second tabs is electrically connected to the electrode terminal, and the other is electrically connected to the end wall. The electrode terminal and the end wall can serve as two exposed electrodes of the cylindrical battery cell. The electrode terminal and the end wall being located on the same side facilitates the assembly of multiple cylindrical battery cells into a group, simplifying the battery structure.

[0062] In some embodiments, the cylindrical battery cell further includes a first current collector, which is located on the side of the first tab facing the end wall and connected to the first tab. The electrode terminal abuts against and connects to the surface of the first current collector facing the end wall. The first current collector can act as a converter to achieve electrical connection between the first tab and the electrode terminal.

[0063] In some embodiments, a terminal recess is provided on the side of the electrode terminal facing the first current collector, and / or, a terminal recess is provided on the side of the electrode terminal away from the first current collector. The bottom wall of the terminal recess is welded to the first current collector. By providing the terminal recess, the thickness of the bottom wall of the terminal recess can be reduced, the power required for external welding of the electrode terminal to the first current collector can be reduced, the risk of welding particles falling into the casing can be reduced, and the reliability of the cylindrical battery cell can be improved.

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

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

[0066] In some embodiments, the height of the housing is 1.3 to 4 times the diameter of the housing. When the housing meets the above dimensional requirements, the structural stability of the housing is high, which can improve the reliability 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] Secondly, embodiments of this application provide a battery comprising a plurality of cylindrical battery cells provided in any of the embodiments of the first aspect.

[0070] Thirdly, embodiments of this application provide an electrical device, including a battery provided in any embodiment of the second aspect, the battery being used to provide electrical energy. Attached Figure Description

[0071] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the drawings without creative effort.

[0072] Figure 1 is a structural schematic diagram of a vehicle provided in some embodiments of this application;

[0073] Figure 2 is a schematic diagram of the explosion of a battery provided in some embodiments of this application;

[0074] Figure 3 is a schematic diagram of the battery module shown in Figure 2;

[0075] Figure 4 is a schematic diagram of the structure of a cylindrical battery cell in some embodiments of this application;

[0076] Figure 5 is an exploded schematic diagram of the cylindrical battery cell shown in Figure 4;

[0077] Figure 6 is a cross-sectional schematic diagram of the electrode assembly of a cylindrical battery cell provided in some embodiments of this application;

[0078] Figure 7 is an enlarged view of Figure 6 at point A within the dashed box;

[0079] Figure 8 is a schematic diagram of the separator of the electrode assembly of a cylindrical battery cell provided in some embodiments of this application;

[0080] Figure 9 is a partial cross-sectional schematic diagram of the electrode assembly of a cylindrical battery cell provided in some other embodiments of this application;

[0081] Figure 10 is a schematic diagram of the separator of the electrode assembly of a cylindrical battery cell provided in some other embodiments of this application;

[0082] Figure 11 is a partial cross-sectional schematic diagram of the electrode assembly of a cylindrical battery cell provided in some embodiments of this application;

[0083] Figure 12 is a schematic diagram of the positive electrode sheet of the electrode assembly provided in some embodiments of this application after being flattened;

[0084] Figure 13 is a cross-sectional schematic diagram of the positive electrode sheet of an electrode assembly provided in some embodiments of this application;

[0085] Figure 14 is a cross-sectional schematic diagram of the negative electrode sheet of an electrode assembly provided in some embodiments of this application;

[0086] Figure 15 is a cross-sectional schematic diagram of the positive electrode sheet provided in some other embodiments of this application;

[0087] Figure 16 is a cross-sectional schematic diagram of the negative electrode sheet provided in some other embodiments of this application;

[0088] Figure 17 is a partial cross-sectional view of the electrode assembly of a cylindrical battery cell provided in some other embodiments of this application;

[0089] Figure 18 is a partial cross-sectional view of the electrode assembly of a cylindrical battery cell provided in some other embodiments of this application;

[0090] Figure 19 is a partial cross-sectional view of the electrode assembly of a cylindrical battery cell provided in some other embodiments of this application;

[0091] Figure 20 is a schematic diagram of the positive electrode sheet of a cylindrical battery cell provided in some other embodiments of this application in an unfolded state;

[0092] Figure 21 is a schematic diagram of the negative electrode sheet of a cylindrical battery cell provided in some other embodiments of this application in an unfolded state;

[0093] Figure 22 is a cross-sectional schematic diagram of the battery cell shown in Figure 4;

[0094] Figure 23 is an enlarged view of Figure 22 at the circular frame;

[0095] Figure 24 is a partial cross-sectional schematic diagram of a battery cell provided in some other embodiments of this application;

[0096] Figure 25 is a partial cross-sectional view of a cylindrical battery cell provided in some other embodiments of this application.

[0097] The accompanying drawings are not drawn to scale.

[0098] The reference numerals in the attached drawings are explained as follows: 1. Vehicle; 2. Battery; 3. Controller; 4. Motor; 5. Housing; 5a. First housing section; 5b. Second housing section; 5c. Receiving 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 tab; 10b. Second tab; 10c. Electrode body; 10d. Center hole; 11. Positive electrode sheet; 111. Positive electrode base; 112. Positive electrode protrusion; 113. Positive electrode recess; 11a. Positive electrode current collector; 11b. Positive electrode film; 11c. Positive electrode particle coating; 12. Negative electrode sheet; 121. Negative electrode base; 122. Negative electrode protrusion; 123. Negative electrode recess; 12a. Negative electrode current collector; 12b. Negative electrode film; 12c. Negative electrode particle coating; 13. Isolator; 131. Isolator base; 13a. Base film; 13b. Coating; 14. Support; 141. First support; 142. Second support; 15. Base; 151. First surface; 20. Outer shell; 21. Housing; 211. End wall; 212. Side wall; 2121. Protrusion; 2122. Recess; 2123. Press-fit; 22. End cap; 30. Electrode terminal; 31. Terminal recess; 32. Through hole; 40. First current collector; 50. Cover plate; 60. Second current collector; 70. Insulating element; G. Gap; G1. First gap; G2. Second gap; C1. Middle region; C2. End region; C3. Transition region; E1. Winding start end; E2. Winding end end; E3. Positive electrode winding start end; E4. Positive electrode winding end end; E5, starting end of negative electrode winding; E6, ending end of negative electrode winding; E7, first end; E8, second end; S, mid-section; P, organic particles; P1, first organic particles; P2, second organic particles; P3, inorganic particle layer; V, winding direction; Z, axial direction. Detailed Implementation

[0099] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0100] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in the description of this application is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms "comprising" and "having," and any variations thereof, in the description, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the description, claims, or accompanying drawings of this application are used to distinguish different objects, not to describe a specific order or hierarchy.

[0101] In this application, the reference to "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment that is mutually exclusive with other embodiments.

[0102] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "attachment" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0103] In this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, in this application, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0104] In the embodiments of this application, the same reference numerals denote the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width, and other dimensions of various components in the embodiments of this application shown in the accompanying drawings, as well as the overall thickness, length, width, and other dimensions of the integrated device, are merely illustrative and should not constitute any limitation on this application.

[0105] In this application, "multiple" means two or more (including two).

[0106] Cylindrical battery cells can be cylindrical secondary batteries. Secondary batteries are battery cells that can be recharged after discharge to activate the active materials and continue to be used.

[0107] A battery can refer to a single physical module comprising one or more cylindrical battery cells to provide higher voltage and capacity.

[0108] A cylindrical battery cell typically includes an electrode assembly and a housing for containing the electrode assembly. The electrode assembly typically includes a positive electrode, a negative electrode, and a separator that separates the positive and negative electrodes.

[0109] During the cyclic charging and discharging process of a cylindrical battery cell, the negative electrode expands due to ion insertion. As the diameter of the cylindrical battery cell increases, the expansion of the negative electrode accumulates and may generate greater expansion force. This increases the pressure between the positive and negative electrodes, causing the electrolyte in the pores of the positive electrode film and the negative electrode film to be squeezed out, affecting the cycle performance of the cylindrical battery cell.

[0110] In addition, the expanding electrode components can also compress the casing, causing the casing to deform or even crack, which affects the reliability of the cylindrical battery cells.

[0111] In view of this, the present application provides a technical solution in which at least one of the positive electrode, negative electrode and separator is provided with multiple support portions to form a gap between the positive electrode and the negative electrode. The gap can provide space for the expansion of the negative electrode, thereby reducing the expansion force, improving the cycle performance of the cylindrical battery cell and improving the reliability of the cylindrical battery cell.

[0112] The cylindrical battery cells described in this application are applicable to batteries and electrical devices that use batteries.

[0113] The electrical device disclosed in this application can 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 electrical device can be, but is not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric vehicles, electric cars, ships, spacecraft, etc. Among them, electric toys can include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc., and spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.

[0114] For ease of explanation, the following embodiments will use a vehicle as an example of an electrical device.

[0115] Figure 1 is a schematic diagram of the structure of a vehicle provided in some embodiments of this application.

[0116] As shown in Figure 1, a battery 2 is installed inside the vehicle 1. The battery 2 can be located at the bottom, front, or rear of the vehicle 1. The battery 2 can be used to power the vehicle 1; for example, the battery 2 can serve as the operating power source for the vehicle 1.

[0117] Vehicle 1 may also include controller 3 and motor 4. Controller 3 is used to control battery 2 to supply power to motor 4, for example, for the power needs of vehicle 1 during start-up, navigation and driving.

[0118] In some embodiments of this application, the battery 2 can not only serve as the operating power source for the vehicle 1, but also as the driving power source for the vehicle 1, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1.

[0119] Figure 2 is an exploded view of a battery provided in some embodiments of this application. As shown in Figure 2, the battery 2 includes a housing 5 and cylindrical battery cells (not shown in Figure 2), with the cylindrical battery cells housed within the housing 5.

[0120] The housing 5 is used to accommodate cylindrical battery cells, and the housing 5 can have various structures. In some embodiments, the housing 5 may include a first housing portion 5a and a second housing portion 5b, which overlap each other, and together define a receiving space 5c for accommodating the cylindrical battery cells. The second housing portion 5b may be a hollow structure with one end open, and the first housing portion 5a may be a plate-like structure, covering the open side of the second housing portion 5b to form a housing 5 with the receiving space 5c; alternatively, both the first housing portion 5a and the second housing portion 5b may be hollow structures with one side open, with the open side of the first housing portion 5a covering the open side of the second housing portion 5b to form a housing 5 with the receiving space 5c. Of course, the first housing portion 5a and the second housing portion 5b can be various shapes, such as cylinders, cuboids, etc.

[0121] To improve the sealing performance after the first housing part 5a and the second housing part 5b are connected, a sealing element, such as sealant or sealing ring, can also be provided between the first housing part 5a and the second housing part 5b.

[0122] Assuming that the first box section 5a covers the top of the second box section 5b, the first box section 5a can also be called the upper box cover, and the second box section 5b can also be called the lower box.

[0123] In battery 2, there can be one or more cylindrical battery cells. If there are multiple cylindrical battery cells, they can be connected in series, parallel, or in a mixed configuration. A mixed configuration means that multiple cylindrical battery cells are connected in both series and parallel configurations. Multiple cylindrical battery cells can be directly connected in series, parallel, or in a mixed configuration and then housed in the housing 5. Alternatively, multiple cylindrical battery cells can first be connected in series, parallel, or in a mixed configuration to form battery modules 6, and then multiple battery modules 6 can be connected in series, parallel, or in a mixed configuration to form a whole and housed in the housing 5.

[0124] A cylindrical battery cell can be the smallest unit that makes up a battery.

[0125] In some embodiments, the housing 5 may include a top cover, a frame, and a bottom plate. The top cover and bottom plate are respectively connected to the frame, forming an enclosed space inside the housing to accommodate individual battery cells. As an example, the frame may include multiple side beams.

[0126] In some embodiments, the housing 5 may be part of the vehicle's chassis structure. For example, a portion of the housing 5 may be at least a portion of the vehicle's floor, or a portion of the housing 5 may be at least a portion of the vehicle's crossbeams and longitudinal beams.

[0127] In some embodiments, battery 2 may be an energy storage device.

[0128] Energy storage devices can be used in energy storage power stations, wind power generation systems, solar power generation systems, mobile power systems, or temporary power supply systems. Energy storage devices can store electrical energy as needed and output it when appropriate. For example, energy storage devices can store electrical energy during off-peak hours and provide power to relevant users or electrical equipment during peak hours.

[0129] Energy storage devices include energy storage containers, energy storage cabinets, etc.

[0130] Figure 3 is a schematic diagram of the battery module shown in Figure 2.

[0131] In some embodiments, as shown in FIG3, there are multiple cylindrical battery cells 7, which are first connected in series, parallel, or mixed to form a battery module 6. The multiple battery modules 6 are then connected in series, parallel, or mixed to form a whole and housed in a casing.

[0132] Multiple cylindrical battery cells 7 in battery module 6 can be electrically connected through busbars to achieve parallel, series, or mixed connection of multiple cylindrical battery cells 7 in battery module 6. There can be one or more busbars, each used to electrically connect at least two cylindrical battery cells 7.

[0133] The cylindrical battery cell 7 can be a lithium-ion battery cell, a sodium-ion battery cell, a sodium-lithium-ion battery cell, a lithium metal battery cell, a sodium metal battery cell, a lithium-sulfur battery cell, a magnesium-ion battery cell, a nickel-metal hydride battery cell, a nickel-cadmium battery cell, a lead-acid battery cell, etc.

[0134] Figure 4 is a structural schematic diagram of a cylindrical battery cell in some embodiments of this application; Figure 5 is an exploded schematic diagram of the cylindrical battery cell shown in Figure 4; Figure 6 is a cross-sectional schematic diagram of the electrode assembly of a cylindrical battery cell provided in some embodiments of this application; Figure 7 is an enlarged schematic diagram of Figure 6 at the dashed box A; Figure 8 is a schematic diagram of the separator of the electrode assembly of a cylindrical battery cell provided in some embodiments of this application.

[0135] Referring to Figures 4 to 8, an embodiment of this application provides a cylindrical battery cell 7, which includes a housing 20 and an electrode assembly 10, at least a portion of which is housed within the housing 20.

[0136] The outer casing 20 is a hollow structure, and its interior forms a space for accommodating the electrode assembly 10 and the electrolyte. The outer casing 20 of the cylindrical battery cell 7 is a cylindrical outer casing.

[0137] As an example, the housing 20 includes a housing 21 and an end cap 22, the housing 21 having an opening and the end cap 22 for closing the opening.

[0138] The housing 21 is a component used to fit the end cap 22 to form the internal cavity of the cylindrical battery cell 7. The formed internal cavity can be used to accommodate the electrode assembly 10, electrolyte, and other components.

[0139] The housing 21 and the end cap 22 can be separate components. For example, an opening can be provided on the housing 21, and the end cap 22 can be used to close the opening to form an internal cavity for the cylindrical battery cell 7.

[0140] The shell 21 can be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, etc.

[0141] The shape of the end cap 22 can be adapted to the shape of the housing 21 to fit the housing 21. The material of the end cap 22 can be the same as or different from the material of the housing 21. Optionally, the end cap 22 can be made of a material with a certain hardness and strength (such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc.), so that the end cap 22 is not easily deformed when subjected to compression and impact, so that the cylindrical battery cell 7 can have higher structural strength and improve reliability.

[0142] The end cap 22 is connected to the housing 21 by welding, bonding, snap-fitting or other means.

[0143] The housing 21 may be open at one end or open at both ends. In some examples, the housing 21 may be a structure with an opening on one side, and one end cap 22 is provided to cover the housing 21. In other examples, the housing 21 may also be a structure with openings on both sides, and two end caps 22 are provided, with the two end caps 22 respectively covering the two openings of the housing 21.

[0144] In some embodiments, the housing 21 includes a sidewall 212 and an endwall 211, the endwall 211 and the end cap 22 being opposite each other along the axial direction Z of the cylindrical battery cell, and the end cap 22 being sealed to the sidewall 212.

[0145] In some embodiments, the sidewall 212 and the endwall 211 are integrally formed.

[0146] Electrode assembly 10 is the component in the cylindrical battery cell 7 where the electrochemical reaction takes place. Electrode assembly 10 can be entirely housed within housing 20 or partially housed within housing 20. For example, a portion of the tabs of electrode assembly 10 can extend outside housing 20.

[0147] Optionally, the electrode assembly 10 is entirely housed within the housing 20.

[0148] In some embodiments, the diameter of the cylindrical battery cell is greater than or equal to 40 mm. Larger diameter cylindrical battery cells have higher capacity, which is beneficial for increasing energy density when multiple cylindrical battery cells are assembled into a group.

[0149] 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 extracted back and forth between the positive electrode 11 and the negative electrode 12.

[0150] In some embodiments, the positive electrode 11 may include a positive current collector and a positive electrode film layer disposed on at least one surface of the positive current collector.

[0151] As an example, the positive current collector has two surfaces opposite each other in its own thickness direction, and the positive electrode film layer is disposed on either or both of the two opposite surfaces of the positive current collector.

[0152] As an example, the positive electrode current collector can be a metal foil or a composite current collector. For example, as a metal foil, it can be aluminum or stainless steel with a silver surface treatment, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel, or titanium, etc. Composite current collectors can include a polymer material base layer and a metal layer. Composite current collectors can be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0153] As an example, the positive electrode film layer includes a positive electrode active material, which may include at least one of the following materials: lithium phosphate, lithium transition metal oxide, and their respective modified compounds. However, this application is not limited to these materials, and other conventional materials that can be used as positive electrode active materials for batteries may also be used. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium phosphate include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), lithium iron phosphate and carbon composites, lithium manganese phosphate (such as LiMnPO4), lithium manganese phosphate and carbon composites, lithium iron manganese phosphate, and lithium iron manganese phosphate and carbon composites. Examples of lithium transition metal oxides include, but are not limited to, lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, and lithium nickel cobalt manganese oxide (such as LiNi). 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (also known as NCM) 333 LiNi 0.5 Co 0.2 Mn 0.3 O2 (also known as NCM) 523 LiNi 0.5 Co 0.25 Mn 0.25 O2 (also known as NCM) 211 LiNi 0.6 Co 0.2 Mn 0.2 O2 (also known as NCM) 622 LiNi 0.8 Co 0.1 Mn 0.1 O2 (also known as NCM) 811 ), lithium nickel cobalt aluminum oxide (such as LiNi) 0.80 Co 0.15 Al 0.05 At least one of O2 and its modified compounds.

[0154] In some embodiments, the negative electrode 12 may include a negative electrode current collector and a negative electrode film layer disposed on at least one surface of the negative electrode current collector.

[0155] As an example, the negative electrode current collector can be a metal foil, foamed metal, foamed carbon, or a composite current collector. For example, as a metal foil, it can be silver-treated aluminum or stainless steel, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel, or titanium, etc. Foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloy, etc. Composite current collectors can include a polymer material base layer and a metal layer. Composite current collectors can be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0156] As an example, the negative electrode current collector has two surfaces opposite each other in its own thickness direction, and the negative electrode film layer is disposed on either or both of the two opposite surfaces of the negative electrode current collector.

[0157] As an example, the negative electrode film layer includes a negative electrode active material. For instance, the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate, etc. Silicon-based materials may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. Tin-based materials may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys. However, this application is not limited to these materials, and other conventional materials that can be used as negative electrode active materials in batteries may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0158] In some embodiments, the positive current collector can be made of aluminum, and the negative current collector can be made of copper.

[0159] In some embodiments, the electrode assembly 10 further includes a separator 13 disposed between the positive electrode 11 and the negative electrode 12. The separator 13 serves to prevent short circuits between the positive and negative electrodes while allowing active ions to pass through.

[0160] In some embodiments, the cylindrical battery cell 7 further includes an electrolyte, which acts as a conductor of ions between the positive electrode 11 and the negative electrode 12. The electrolyte can be liquid, gel-like, or solid.

[0161] In some embodiments, the liquid electrolyte includes an electrolyte salt and a solvent.

[0162] As an 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 difluorooxalate borate, lithium dioxalate borate, lithium difluorodioxalate phosphate, and lithium tetrafluorooxalate phosphate.

[0163] As an example, the solvent may be selected from at least one of ethylene carbonate, propylene carbonate, methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butyl 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 an ether solvent. Ether solvents 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, methyl tetrahydrofuran, diphenyl ether, and crown ethers.

[0164] In some embodiments, the gel electrolyte comprises a polymer-based backbone network coupled with an ionic liquid-lithium salt.

[0165] In some embodiments, the solid electrolyte includes a polymer solid electrolyte, an inorganic solid electrolyte, and a composite solid electrolyte.

[0166] As an example, polymer solid electrolytes can be polyether (polyoxyethylene), polysiloxane, polycarbonate, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, monoionic polymers, polyionic liquids-lithium salts, cellulose, etc.

[0167] As an example, inorganic solid electrolytes can be one or more of the following: oxide solid electrolytes (crystalline perovskite, sodium superconducting ion conductor, garnet, amorphous LiPON thin film), sulfide solid electrolytes (crystalline lithium superconducting ion conductor (lithium germanium phosphorus sulfide, silver sulfide germanium ore), amorphous sulfides), halide solid electrolytes, nitride solid electrolytes, and hydride solid electrolytes.

[0168] As an example, composite solid electrolytes are formed by adding inorganic solid electrolyte fillers to polymer solid electrolytes.

[0169] In some embodiments, the positive electrode 11, the negative electrode 12, and the separator 13 are wound together.

[0170] The electrode assembly 10 has a wound structure. For example, the positive electrode 11, the separator 13, and the negative electrode 12 are wound into a cylindrical wound structure.

[0171] In some embodiments, the diameter of the cylindrical battery cell 7 is greater than or equal to 40 mm. The cylindrical battery cell 7 includes a housing 20 and an electrode assembly 10, at least a portion of which is housed within the housing 20.

[0172] As an example, the diameter of the casing is greater than or equal to 40mm.

[0173] The electrode assembly 10 includes a positive electrode 11, a negative electrode 12, and a separator 13. The positive electrode 11, the negative electrode 12, and the separator 13 are wound together, and the separator 13 separates the positive electrode 11 and the negative electrode 12.

[0174] The negative electrode active material of the negative electrode 12 includes at least one of silicon-based materials and carbon-based materials.

[0175] At least one of the positive electrode 11, the negative electrode 12, and the separator 13 includes a base 15 and a plurality of support portions 14 disposed on the base 15. The base 15 has two first surfaces 151 disposed opposite to each other along its own thickness direction, and the plurality of support portions 14 protrude from at least one first surface 151 to form a gap G between the positive electrode 11 and the negative electrode 12.

[0176] As an example, carbon-based materials include at least one of artificial graphite and natural graphite.

[0177] As an example, silicon-based materials include at least one of elemental silicon, silicon oxides, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys.

[0178] As an example, multiple support portions 14 are distributed on the first surface 151.

[0179] In some examples, a first surface 151 of the base 15 is provided with a plurality of support portions 14. Of course, the base 15 may be provided with a plurality of support portions 14 along the radially inward first surface 151 of the cylindrical battery cell, or the base 15 may be provided with a plurality of support portions 14 along the radially outward first surface 151 of the cylindrical battery cell.

[0180] In other examples, both first surfaces 151 of the base 15 are provided with a plurality of supports 14.

[0181] In the electrode assembly 10, one of the positive electrode 11, the negative electrode 12 and the separator 13 may be provided with a support portion 14, or both of them may be provided with a support portion 14, or all three of them may be provided with a support portion 14.

[0182] In some examples, the positive electrode 11 includes a base and multiple support portions. For ease of description, the base of the positive electrode 11 may be referred to as the positive electrode base. Optionally, the negative electrode 12 and the separator 13 may or may not have support portions. Among the multiple support portions of the positive electrode 11, some of the support portions may contact the separator, or all of the support portions may contact the separator.

[0183] In some examples, the negative electrode 12 includes a base and multiple support portions. For ease of description, the base of the negative electrode may be referred to as the negative electrode base. Optionally, the positive electrode 11 and the separator 13 may or may not have support portions. Among the multiple support portions of the negative electrode 12, some support portions may contact the separator, or all support portions may contact the separator.

[0184] In some examples, the separator 13 includes a base 15 and a plurality of support portions 14. For ease of description, the base of the separator 13 may be referred to as the separator base 131. Optionally, the positive electrode 11 and the negative electrode 12 may or may not have support portions. As an example, the positive electrode 11 may contact a portion of the support portion of the separator 13, and / or, the negative electrode 12 may contact a portion of the support portion of the separator 13.

[0185] As an example, the gap G can be a space located between the positive electrode 11 and the negative electrode 12 that is not filled by the separator 13. Specifically, the gap G can be a space located between the positive electrode film layer and the negative electrode film layer that is not filled by the separator 13.

[0186] In some examples, a gap G is provided on the outer side of the positive electrode 11; in other examples, a gap G is provided on the inner side of the positive electrode 11; and in still other examples, gaps G are provided on both the inner and outer sides of the positive electrode 11.

[0187] The support part 14 can be rigid or flexible.

[0188] In some examples, at least two of the positive electrode 11, the negative electrode 12, and the separator 13 are provided with a support portion 14, which may be formed in the same or different ways.

[0189] Multiple support portions 14 protrude and support at least one of the positive electrode 11 and the negative electrode 12, thereby forming a gap G between the positive electrode 11 and the negative electrode 12. During the cycling process of the cylindrical battery cell 7, the gap G provides space for the expansion of the negative electrode 12, reducing the pressure between the positive electrode 11 and the negative electrode 12. This reduces the compression of the electrolyte in the internal pores of the positive electrode film layer of the positive electrode 11 and the internal pores of the negative electrode film layer of the negative electrode 12, reducing the concentration difference of electrolyte in different regions inside the electrode and improving the cycling performance of the cylindrical battery cell 7 with a larger diameter. The gap G can reduce the expansion of the electrode assembly 10, thereby reducing the compression of the casing 20, reducing the risk of deformation and cracking of the casing 20, and improving the reliability of the cylindrical battery cell 7. By setting the gap G, the increase in expansion force caused by increasing the diameter of the cylindrical battery cell 7 can be reduced, thus increasing the diameter of the cylindrical battery cell 7 and improving its capacity.

[0190] The gap G can also accommodate electrolyte to improve the wetting effect of the electrolyte on the positive and negative electrode plates and improve the cycle performance of the cylindrical battery cell.

[0191] In addition, when the negative electrode 12 experiences ion deposition problems during cycling, such as lithium deposition, the gap G can provide space for the deformation of the separator 13, so that the separator 13 can release the pressure exerted on it by the lithium dendrites through deformation, thereby avoiding the separator 13 from being punctured to a certain extent, reducing the risk of short circuit and improving reliability.

[0192] In some embodiments, the negative electrode active material includes a carbon-based material. Carbon-based materials have high cycle stability and can improve the cycle performance of cylindrical battery cells.

[0193] In some embodiments, the support portion 14 is configured to be compressible. During the cycling of the cylindrical battery cell 7, the support portion 14 can be compressed under pressure, thereby providing more expansion space for the negative electrode 12. The compressible support portion 14 can release stress through compression deformation, thereby reducing the risk of the positive electrode 11 or the negative electrode 12 being damaged by the support portion 14 and improving reliability.

[0194] In some embodiments, the plurality of support portions 14 include a first support portion 141 and a second support portion 142. On the same side of the base 15, the height H1 of the first support portion 141 protruding from the first surface 151 is greater than the height H2 of the second support portion 142 protruding from the first surface 151.

[0195] There may be one or more first support portions 141. There may be one or more second support portions 142. Optionally, there may be multiple first support portions 141 and multiple second support portions 142.

[0196] The first support portion 141 has a relatively large height, which can support the positive electrode 11 or the negative electrode 12 to form a larger gap G, thereby providing more space for the expansion of the negative electrode 12. The second support portion 142 has a smaller height and occupies less space. As the negative electrode 12 expands, the gap G gradually decreases; the second support portion 142 can be compressed only after the negative electrode 12 has expanded to a certain extent, thus reducing the pressure on the negative electrode 12 in the initial stage of expansion. When the second support portion 142 is compressed, it can slow down the expansion of the negative electrode 12 to a certain extent, reduce the electrolyte squeezed out by the negative electrode 12, and improve the cycle performance of the cylindrical battery cell 7.

[0197] In some embodiments, there are multiple first support portions 141 and multiple second support portions 142.

[0198] In some embodiments, the height of the first support portion 141 is 1.1 to 15 times the height of the second support portion 142, and optionally 2 to 7 times.

[0199] In some embodiments, the isolation member 13 includes an isolation base 131 and a plurality of support portions 14. Optionally, the plurality of support portions 14 of the isolation member 13 includes a first support portion 141 and a second support portion 142.

[0200] In some embodiments, at least one of the positive electrode 11, the negative electrode 12, and the separator 13 includes a plurality of organic particles P, and the support portion 14 includes organic particles P.

[0201] For example, in the electrode assembly 10, one of the positive electrode 11, the negative electrode 12 and the separator 13 may be provided with organic particles P, or both may be provided with organic particles P, or all three may be provided with organic particles P.

[0202] Organic particles P can act as a support to form gaps G. When thermal runaway occurs in the cylindrical battery cell 7, organic particles P can form a gel film structure at high temperatures, thereby reducing the diffusion channels of active ions, delaying the time of thermal propagation, and thus improving the reliability of the cylindrical battery cell 7.

[0203] For example, organic particles P can be formed on the positive electrode 11, the negative electrode 12, or the separator 13 by coating. Forming the support portion 14 by coating organic particles P simplifies the molding process.

[0204] In some embodiments, the plurality of organic particles P includes a first organic particle P1 and a second organic particle P2, wherein the number-average particle size of the first organic particle P1 is greater than the number-average particle size of the second organic particle P2.

[0205] It should be noted that the number-average path of organic particles is the arithmetic mean of the particle sizes of organic particles, calculated based on the number of organic particles. The particle size of an organic particle can refer to the distance between the two farthest points on the organic particle.

[0206] The first organic particles P1, with a larger number-average particle size, can support the positive electrode 11 or the negative electrode 12 to form a larger gap G, thus providing more space for the expansion of the negative electrode 12. The second organic particles P2, with a smaller number-average particle size, can be compressed after the negative electrode 12 has expanded to a certain extent, which can reduce the pressure on the negative electrode 12 in the initial stage of expansion. When the second organic particles P2 are compressed, they can slow down the expansion of the negative electrode 12 to a certain extent, reduce the electrolyte squeezed out by the negative electrode 12, and improve the cycle performance of the cylindrical battery cell 7.

[0207] In some embodiments, the plurality of support portions 14 include a first support portion 141 and a second support portion 142. On the same side of the base 15, the height of the first support portion 141 protruding from the first surface is greater than the height of the second support portion 142 protruding from the first surface. The organic particles P include a first organic particle P1 and a second organic particle P2; the first support portion 141 includes the first organic particle P1, and the second support portion 142 includes the second organic particle P2.

[0208] By setting first organic particles P1 and second organic particles P2 with different number-average particle sizes, a first support portion 141 and a second support portion 142 with different heights can be formed. The first support portion 141 has a larger height, which can support the positive electrode 11 or the negative electrode 12 to form a larger gap G, thereby providing more space for the expansion of the negative electrode 12. The second support portion 142 can be compressed after the negative electrode 12 has expanded to a certain extent, which can reduce the pressure on the negative electrode 12 in the initial stage of expansion. When the second support portion 142 is compressed, it can slow down the expansion of the negative electrode 12 to a certain extent, reduce the electrolyte squeezed out by the negative electrode 12, and improve the cycle performance of the cylindrical battery cell 7.

[0209] 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-10 μm.

[0210] In some embodiments, the number-average particle size of the first organic particle P1 is 12 μm-25 μm. For example, the number-average particle size of the first organic particle P1 can be 12 μm, 13 μm, 15 μm, 16 μm, 18 μm, 20 μm, 21 μm, 22 μm, 24 μm or 25 μm.

[0211] In some embodiments, the number-average particle size of the second organic particle P2 is 2 μm-9 μm. For example, the number-average particle size of the first organic particle P1 can be 2 μm, 2.5 μm, 3 μm, 4 μm, 5 μm, 5.5 μm, 6 μm, 7 μm, 8 μm or 9 μm.

[0212] 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 greater than or equal to 1.5.

[0213] In some embodiments, the first organic particle P1 is a secondary particle.

[0214] In some embodiments, the second organic particle P2 is a primary particle.

[0215] It should be noted that primary particles and secondary particles have meanings known in the art. Primary particles refer to particles that have not formed aggregates. Secondary particles refer to aggregated particles formed by the aggregation of two or more primary particles.

[0216] In some embodiments, the plurality of organic particles P includes a first organic particle P1, the first organic particle P1 including a homopolymer or copolymer of fluorinated alkenyl monomer units, a homopolymer or copolymer of olefinic monomer units, a homopolymer or copolymer of unsaturated nitrile monomer units, a homopolymer or copolymer of epoxide monomer units, and one or more of the modified compounds of the above homopolymers or copolymers.

[0217] In some embodiments, the fluorinated alkenyl monomer unit may be selected from one or more of difluoroethylene, vinylidene fluoride, trifluoroethylene, trifluorochloroethylene, tetrafluoroethylene, and hexafluoropropylene.

[0218] In some embodiments, the olefinic monomer unit may be selected from one or more of ethylene, propylene, butadiene, isoprene, etc.

[0219] In some embodiments, the unsaturated nitrile monomer unit may be selected from one or more of acrylonitrile, methacrylonitrile, etc.

[0220] In some embodiments, the alkyl oxide monomer unit may be selected from one or more of ethylene oxide, propylene oxide, etc.

[0221] In some embodiments, the first organic particle P1 includes one or more of the following: polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinylidene fluoride, polyvinylidene fluoride, polyethylene, polypropylene, polyacrylonitrile, polyethylene oxide, copolymers of different fluorinated alkenyl monomer units, copolymers of fluorinated alkenyl monomer units and olefin monomer units, copolymers of fluorinated alkenyl monomer units and acrylic monomer units, copolymers of fluorinated alkenyl monomer units and acrylate monomer units, and modified compounds of the above homopolymers or copolymers.

[0222] In some embodiments, the first organic particle P1 may include one or more of the following: 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 above copolymers.

[0223] In some embodiments, the plurality of organic particles P includes a second organic particle P2, which includes one or more of the following: homopolymers or copolymers of acrylate monomer units, homopolymers or copolymers of acrylic monomer units, homopolymers or copolymers of styrene monomer units, polyurethane compounds, rubber compounds, and modified compounds of the above-mentioned homopolymers or copolymers.

[0224] In some embodiments, the second organic particle P2 comprises one or more of the following: a copolymer of acrylate monomer units and styrene monomer units, a copolymer of acrylate monomer units and styrene monomer units, a copolymer of acrylate monomer units-acrylate monomer units-styrene monomer units, a copolymer of styrene monomer units and unsaturated nitrile monomer units, a copolymer of styrene monomer units-olefin monomer units-unsaturated nitrile monomer units, and a modified compound of the above copolymers.

[0225] 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.

[0226] In some embodiments, the acrylic monomer unit may be selected from one or more of acrylic acid, methacrylic acid, etc.

[0227] In some embodiments, the styrene monomer unit may be selected from one or more of styrene, methylstyrene, etc.

[0228] In some embodiments, the unsaturated nitrile monomer unit may be selected from one or more of acrylonitrile, methacrylonitrile, etc.

[0229] In some embodiments, the second organic particle P2 may include one or more of the following: butyl acrylate-styrene copolymer, butyl methacrylate-isooctyl methacrylate copolymer, isooctyl methacrylate-styrene copolymer, methacrylate-methacrylate-styrene copolymer, methyl acrylate-isooctyl methacrylate-styrene copolymer, butyl acrylate-isooctyl methacrylate-styrene copolymer, butyl acrylate-isooctyl methacrylate-styrene copolymer, butyl methacrylate-isooctyl methacrylate-styrene copolymer, butyl methacrylate-isooctyl methacrylate-styrene copolymer, styrene-acrylonitrile copolymer, styrene-butadiene-acrylonitrile copolymer, methyl acrylate-styrene-acrylonitrile copolymer, isooctyl methacrylate-styrene-acrylonitrile copolymer, styrene-vinyl acetate copolymer, styrene-vinyl acetate-pyrrolidone copolymer, and modified compounds of the above materials.

[0230] In some embodiments, the separator 13 includes a base 15 and a plurality of supports 14, the supports 14 including organic particles disposed on the base.

[0231] The organic particle P may protrude entirely from the base 15. Alternatively, a portion of the organic particle may be embedded in the base 15, while another portion protrudes from the base 15.

[0232] Organic particles P can support the positive electrode 11 or the negative electrode 12 to increase the gap G and provide space for the expansion of the negative electrode 12.

[0233] For the sake of simplicity, the base 15 of the spacer 13 may be referred to as the spacer base 131.

[0234] In some embodiments, the base 15 of the separator 13 includes a base film 13a and an inorganic particle layer P3 disposed on the base film 13a, wherein organic particles P at least partially protrude from the inorganic particle layer P3.

[0235] The inorganic particle layer P3 consists of multiple inorganic particles, and sufficient and unevenly distributed voids are formed between the inorganic and organic particles, which can improve the air permeability of the separator and enable the cylindrical battery cell to have better cycle performance and reliability.

[0236] In some embodiments, the separator 13 includes a coating 13b disposed on at least one surface of the base film 13a. The coating 13b includes an inorganic particulate layer P3 and a plurality of organic particles P.

[0237] In some examples, inorganic particles can be coated onto the base film 13a first to form an inorganic particle layer P3, and then multiple organic particles can be coated onto the inorganic particle layer P3. In other examples, inorganic and organic particles can be mixed first and then coated together onto the base film 13a.

[0238] In some examples, one surface of the base film 13a is coated with a coating 13b comprising an inorganic particle layer P3 and a plurality of organic particles P, while the other surface of the base film 13a may be uncoated or coated with the inorganic particle layer P3. In other examples, both surfaces of the base film 13a are coated with a coating 13b comprising an inorganic particle layer P3 and organic particles P.

[0239] The inorganic and organic particles P form sufficient and unevenly distributed voids, which improves the permeability of the separator 13, giving the cylindrical battery cell 7 better cycle performance and reliability. The organic particles P can support the positive electrode 11 or the negative electrode 12 to increase the gap G and provide space for the expansion of the negative electrode 12.

[0240] 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).

[0241] In some embodiments, the volume average particle size Dv50 of the inorganic particles is ≤2.5μm; for example, the particle size of the inorganic particles can be 0.5μm-2.5μm, 1.5μm-2.5μm, 0.3μm-0.7μm, etc.

[0242] In some embodiments, the surface of the base film 13a facing the positive electrode 11 is coated with a coating 13b, and / or the surface of the base film 13a facing the negative electrode 12 is coated with a coating 13b.

[0243] In some embodiments, at least a portion of the gap G has a radial dimension W of 5 μm to 60 μm.

[0244] As an example, the radial dimension of the gap G can be the radial dimension of the gap G along the cylindrical battery cell. The radial dimension W of the gap G can be the same or different at different locations.

[0245] Optionally, the radial dimension W of each part of the gap G is 5μm-60μm.

[0246] Optionally, the radial dimension W of the gap G can be 5μm, 6μm, 8μm, 10μm, 15μm, 20μm, 25μm, 30μm, 35μm, 40μm, 45μm, 50μm, 55μm, 60μm or a range of any two of the above values.

[0247] As an example, the radial dimension of the gap G can be measured as follows:

[0248] Discharge the cylindrical battery cells to the lower cutoff voltage (e.g., 2.5V);

[0249] Using CT (Computed Tomography) technology, X-rays are used to obtain cross-sectional images of the electrode assembly. This cross-section is perpendicular to the axis of the cylindrical battery cell and shows the positive electrode film, negative electrode film, and separator.

[0250] Based on this image, the distance D1 between the outer surface of the 6th positive electrode layer and the inner surface of the 10th positive electrode layer is measured in the radial direction of the electrode assembly;

[0251] Disassemble the cylindrical battery cell and measure the thickness t1 of the positive electrode, the thickness t2 of the negative electrode, and the thickness t3 of the separator.

[0252] Between the outer surface of the 6th positive electrode layer and the inner surface of the 10th positive electrode layer, there are 3 positive electrode layers, 4 negative electrode layers, and 8 separator layers; 8 gaps are formed between the outer surface of the 6th positive electrode layer and the inner surface of the 10th positive electrode layer. W=(D1-3×t1-4×t2-8×t3) / 8.

[0253] It should be noted that D1 is measured at the location where no support is provided on the outer surface of the 6th positive electrode layer and the location where no support is provided on the inner surface of the 10th positive electrode layer. For example, based on the image, a virtual straight line is defined, which passes through the center of the cross-section. Based on the image and the virtual straight line, along a direction away from the center of the cross-section and parallel to the virtual straight line, the first intersection point between the outer surface of the 6th positive electrode layer and the virtual straight line is obtained, and the second intersection point between the inner surface of the 10th positive electrode layer and the virtual straight line is obtained. The distance between the first and second intersection points is measured, and this distance is D1.

[0254] t1 is measured on the portion of the positive electrode sheet where the positive electrode film layer is provided but where no support is provided. For example, on the portion of the positive electrode sheet where no support is provided, 50 locations are randomly selected, 50 thickness values ​​are measured, and then the average value of the 50 thickness values ​​is calculated. This average value can be used as t1.

[0255] Thickness t2 is measured on the portion of the negative electrode sheet where the negative electrode film layer is located but where no support is provided. For example, 50 locations are randomly selected on the portion of the negative electrode sheet where no support is provided, and 50 thickness values ​​are measured. The average value of the 50 thickness values ​​is then calculated and can be used as t2.

[0256] Thickness t3 is measured on the portion of the separator without support. For example, 50 locations are randomly selected on the portion of the separator without support, 50 thickness values ​​are measured, and then the average of the 50 thickness values ​​is calculated. This average value can be used as t3.

[0257] In this embodiment, the radial dimension W of the gap G is limited to greater than or equal to 5 μm, which provides space for the expansion of the negative electrode 12, reduces the expansion force, improves the cycle performance of the cylindrical battery cell 7, and reduces the risk of deformation and cracking of the casing 20. In this embodiment, the radial dimension W of the gap G is limited to less than or equal to 60 μm to shorten the ion migration path between the positive electrode 11 and the negative electrode 12, reduce the internal resistance of the cylindrical battery cell 7, reduce heat generation, and reduce the impact of the gap G on the energy density.

[0258] In some embodiments, the gap G includes a first gap G1 and a second gap G2, the first gap G1 being formed between the positive electrode 11 and the separator 13, and the second gap G2 being formed between the negative electrode 12 and the separator 13.

[0259] As an example, the radial dimension of the first gap G1 is W1, and the radial dimension of the second gap G2 is W2. The radial dimension W of the gap G is W = W1 + W2.

[0260] Both the first gap G1 and the second gap G2 can provide space for the expansion of the negative electrode film layer 12b, thereby reducing the squeezing effect on the outer casing 20, reducing the risk of deformation and cracking of the outer casing 20, and improving the reliability of the cylindrical battery cell 7.

[0261] In some embodiments, a gap G is provided on the inner side of the positive electrode 11, and no gap G is provided on the outer side of the positive electrode 11. Optionally, the gap located on the inner side of the positive electrode 11 includes a first gap G1 and a second gap G2.

[0262] In some other embodiments, a gap G is provided on the outer side of the positive electrode 11, and no gap G is provided on the inner side of the positive electrode 11. Optionally, the gap G located on the outer side of the positive electrode 11 includes a first gap G1 and a second gap G2.

[0263] In some embodiments, gaps G are provided on both the inner and outer sides of the positive electrode 11. Optionally, the gap G located on the inner side of the positive electrode 11 includes a first gap G1 and a second gap G2, and the gap located on the outer side of the positive electrode 11 includes a first gap G1 and a second gap G2. Specifically, a first gap G1 is formed between the positive electrode 11 and the separator 13 located on the inner side of the positive electrode 11, and another first gap G1 is formed between the positive electrode 11 and the separator 13 located on the outer side of the positive electrode 11; a second gap G2 is formed between the negative electrode 12 and the separator 13 located on the outer side of the negative electrode 12, and another second gap G2 is formed between the negative electrode 12 and the separator 13 located on the inner side of the negative electrode 12.

[0264] 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.

[0265] The gap G is wound multiple times along the winding direction V.

[0266] As an example, the positive electrode 11 has a positive electrode winding start end E3 and a positive electrode winding end E4, and the negative electrode 12 has a negative electrode winding start end E5 and a negative electrode winding end E6. Along the winding direction V, the negative electrode winding end E6 extends beyond the positive electrode winding end E4; in the opposite direction of the winding direction V, the negative electrode winding start end E5 extends beyond the positive electrode winding start end E3. Both ends of the negative electrode 12 extend beyond the positive electrode 11 along the winding direction V, providing an intercalation space for active ions extracted from the positive electrode 11, thereby reducing the risk of ion extraction. In the radial direction of the cylindrical battery cell, the winding start end E1 of the gap G corresponds to the positive electrode winding start end E3, and the winding end end E2 of the gap G corresponds to the positive electrode winding end E4.

[0267] In some embodiments, there are two gaps G, which are respectively disposed on both sides of the positive electrode 11.

[0268] As an example, in the radial direction of the cylindrical battery cell 7, the winding start end E1 of the gap G located inside the positive electrode 11 is located inside the positive electrode winding start end E3, and the winding start end E1 of the gap G located outside the positive electrode 11 is located outside the positive electrode winding start end E3.

[0269] In this embodiment of the application, by setting two gaps G, the expansion of the electrode assembly 10 can be further reduced, thereby reducing the squeezing effect on the outer casing 20, reducing the risk of deformation and cracking of the outer casing 20, and improving the reliability of the cylindrical battery cell.

[0270] In some embodiments, the electrode assembly 10 has a central hole 10d in the middle.

[0271] The central hole 10d can provide space for the expansion of the negative electrode film, thereby reducing the squeezing effect on the outer casing 20, reducing the risk of deformation and cracking of the outer casing 20, and improving the reliability of the cylindrical battery cell 7.

[0272] The central hole 10d can serve as a flow channel for the electrolyte, improving the wetting effect of the electrolyte on the electrode assembly 10. In the event of thermal runaway in the cylindrical battery cell 7, the central hole 10d can serve as a gas venting channel, increasing the gas venting rate and reducing the risk of explosion.

[0273] Figure 9 is a partial cross-sectional schematic diagram of the electrode assembly of a cylindrical battery cell provided in some other embodiments of this application; Figure 10 is a schematic diagram of the separator of the electrode assembly of a cylindrical battery cell provided in some other embodiments of this application.

[0274] Referring to Figures 9 and 10, in some embodiments, multiple support portions 14 are provided on both sides of the separator 13. By providing multiple support portions 14 on both sides of the separator 13, the gap G can be increased, providing more space for the expansion of the negative electrode sheet 12.

[0275] In some embodiments, the gap G includes a first gap G1 and a second gap G2, the first gap G1 being formed between the positive electrode 11 and the separator 13, and the second gap G2 being formed between the negative electrode 12 and the separator 13.

[0276] As an example, the radial dimension of the first gap G1 is W1, and the radial dimension of the second gap G2 is W2. The radial dimension W of the gap G is W = W1 + W2.

[0277] In the thickness direction of the spacer 13, the support portions 14 located on both sides of the spacer 13 may or may not overlap.

[0278] By providing multiple support portions 14 on both sides of the separator 13, a first gap G1 and a second gap G2 can be formed on both sides of the separator 13, providing more space for the expansion of the negative electrode sheet 12.

[0279] In some embodiments, a coating 13b is provided on both sides of the base film 13a.

[0280] Figure 11 is a partial cross-sectional schematic diagram of the electrode assembly of a cylindrical battery cell provided in some embodiments of this application; Figure 12 is a schematic diagram of the positive electrode sheet of the electrode assembly provided in some embodiments of this application after being flattened; Figure 13 is a cross-sectional schematic diagram of the positive electrode sheet of the electrode assembly provided in some embodiments of this application; Figure 14 is a cross-sectional schematic diagram of the negative electrode sheet of the electrode assembly provided in some embodiments of this application.

[0281] Referring to Figures 11 to 14, in some embodiments, the positive electrode 11 is provided with a support portion 14.

[0282] In the embodiments of this application, the support portion 14 may be provided on one side of the positive electrode 11, or the support portion 14 may be provided on both sides of the positive electrode 11.

[0283] In some embodiments, the positive electrode 11 includes a positive electrode base 111 and a plurality of positive electrode protrusions 112 protruding from the surface of the positive electrode base 111. The positive electrode 11 has a positive electrode recess 113 on the side away from the positive electrode protrusions 112, corresponding to the position of the positive electrode protrusions 112. The support portion 14 of the positive electrode 11 includes the positive electrode protrusions 112.

[0284] As an example, the number of positive electrode recesses 113 and positive electrode protrusions 112 are the same, and they are set in a one-to-one correspondence.

[0285] The positive electrode protrusion 112 can support the separator 13 and the negative electrode 12, thereby forming a gap G. The positive electrode recess 113 can accommodate the electrolyte and also provide space for the expansion of the negative electrode 12.

[0286] As an example, the positive electrode protrusion 112 and the positive electrode recess 113 can be formed by stamping the positive electrode sheet 11.

[0287] In some embodiments, organic particles may be disposed on the surface of the positive electrode protrusion 112.

[0288] In some embodiments, the positive electrode 11 includes a positive electrode tab connected to the positive electrode base 111.

[0289] In some embodiments, all the positive electrode protrusions 112 protrude toward the same side of the positive electrode base 111. Correspondingly, a plurality of support portions 14 are disposed on the same side of the positive electrode base 111.

[0290] The embodiments of this application can simplify the forming process of the positive electrode 11.

[0291] In some embodiments, there are multiple positive electrode protrusions 112, some of which protrude from the positive electrode base 111 at a higher height, while others protrude from the positive electrode base 111 at a lower height. The first support portion includes the higher positive electrode protrusions 112, and the second support portion includes the lower positive electrode protrusions 112.

[0292] In some embodiments, the side of the separator 13 facing the positive electrode recess 113 is provided with a plurality of support portions 14, and at least a portion of the plurality of support portions 14 of the separator 13 does not overlap with the positive electrode recess 113 in the radial direction.

[0293] In some embodiments, the positive electrode 11 includes a positive current collector 11a and a positive electrode film layer 11b disposed on the surface of the positive current collector 11a. Exemplarily, the portion of the positive current collector 11a without the positive electrode film layer 11b may be a positive electrode tab.

[0294] In some embodiments, the positive electrode protrusion 112 is formed in the region of the positive electrode sheet 11 where the positive electrode film layer 11b is provided.

[0295] In some embodiments, the negative electrode 12 includes a negative electrode current collector 12a and a negative electrode film layer 12b disposed on at least one side of the negative electrode current collector 12a and containing a negative electrode active material.

[0296] For example, the portion of the negative electrode current collector 12a that is not disposed on the negative electrode film layer 12b may be a negative electrode tab.

[0297] In some embodiments, the negative electrode active material includes a silicon-based material. The introduction of a silicon-based material can improve the capacity of the negative electrode active material and increase the energy density of the cylindrical battery cell 7; the gap G can provide space for the expansion of the silicon-based material, thereby reducing the influence of the silicon-based material on the expansion force.

[0298] For example, silicon can exist in the form of silicon-based materials, such as elemental silicon, silicon oxides, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys.

[0299] In some embodiments, the silicon content of the silicon element in the negative electrode film layer 12b is 2% to 19% by mass. Exemplarily, the silicon content in the negative electrode film layer can be 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, or any range of two of the above values.

[0300] The mass content of silicon in the negative electrode film is a well-known concept in the art and can be detected using well-known equipment and methods. For example, the negative electrode sheet can be immersed in a solvent (e.g., water) to separate the negative electrode active material from the negative electrode current collector. The substances in the negative electrode film can be obtained by filtration and used as a test sample. The silicon content can be obtained by using an ICAP7400 inductively coupled plasma atomic emission spectrometer from Thermo Fisher Scientific, USA, in accordance with the GB / T30902-2014 standard.

[0301] In this embodiment, the mass content of silicon in the negative electrode film 12b is limited to greater than or equal to 2% to increase the capacity of the negative electrode and improve 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 silicon-based materials on the expansion force. In this embodiment, the mass content of silicon in the negative electrode film 12b is limited to less than or equal to 19% to limit the expansion of the cylindrical battery cell and improve the cycle performance of the cylindrical battery cell.

[0302] In this embodiment, the mass content of silicon in the negative electrode film 12b is limited to 2% to 19% to balance the expansion and capacity of the negative electrode sheet to a certain extent, while taking into account the cycle performance and energy density of the cylindrical battery cell.

[0303] In some embodiments, the mass content of silicon in the negative electrode film layer 12b is 6% to 13%.

[0304] In some embodiments, the areal density of the negative electrode 12 is greater than or equal to 3.2 mAh / cm³. 2 .

[0305] The capacity areal density of the negative electrode is a well-known concept in the art and can be detected using well-known equipment and methods. For example, the aforementioned negative electrode and lithium metal sheet can be used as the counter electrode, along with an electrolyte and a separator, and assembled into a CR2430 coin cell in an argon-protected glove box. After the resulting coin cell is left to stand for 12 hours, it is discharged at 25°C with a constant current of 0.05C to 0.005V, left to stand for 10 minutes, and then discharged again with a constant current of 50μA to 0.005V. After standing for 10 minutes, it is discharged again with a constant current of 10μA to 0.005V. Then, it is charged at a constant current of 0.1C to 2V, and the charging capacity is recorded. The ratio of the charging capacity to the area of ​​the negative electrode is the capacity areal density. As an example, the electrolyte and separator described in Example 1 below can be used.

[0306] The areal density of the negative electrode sheet is related to its expansion. In this embodiment, by setting a gap, the impact of increasing the areal density of the negative electrode sheet on the expansion force can be reduced, thereby increasing the capacity of the negative electrode sheet and improving the energy density of the cylindrical battery cell.

[0307] For example, the areal density of the negative electrode 12 can be 3.2 mAh / cm³. 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 / cm 2 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 a range consisting of any two of the above values.

[0308] In some embodiments, the areal density of the negative electrode 12 is 3.3 mAh / cm³. 2 Up to 11.5mAh / cm 2 The embodiments of this application can, to a certain extent, balance the capacity and expansion of the negative electrode, while taking into account the energy density and cycle performance of the cylindrical battery cell.

[0309] In some embodiments, the areal density of the negative electrode 12 is 3.96 mAh / cm³. 2 Up to 7.56mAh / cm 2 This can further balance the energy density and cycle performance of cylindrical battery cells.

[0310] In some embodiments, the negative electrode 12 is provided with a plurality of support portions 14.

[0311] In this embodiment, the negative electrode 12 may have multiple support portions 14 on one side, or multiple support portions 14 may be provided on both sides of the negative electrode 12.

[0312] In some embodiments, the negative electrode 12 includes a negative electrode base 121 and a plurality of negative electrode protrusions 122 protruding from the surface of the negative electrode base 121. The negative electrode 12 has a negative electrode recess 123 on the side away from the negative electrode protrusions 122, corresponding to the position of the negative electrode protrusions 122. The support portion 14 of the negative electrode 12 includes the negative electrode protrusions 122.

[0313] As an example, the number of negative electrode recesses 123 and negative electrode protrusions 122 are the same, and they are set in a one-to-one correspondence.

[0314] The negative electrode protrusion 122 can support the separator 13 and the positive electrode 11, thereby forming a gap G. The negative electrode recess 123 can accommodate the electrolyte and also provide space for the expansion of the negative electrode 12.

[0315] As an example, the negative electrode protrusion 122 and the negative electrode recess 123 can be formed by stamping the negative electrode sheet 12.

[0316] In some embodiments, organic particles may be disposed on the surface of the negative electrode protrusion 122.

[0317] In some embodiments, the negative electrode includes a negative electrode tab connected to the negative electrode base 121.

[0318] In some embodiments, there are multiple negative electrode protrusions 122.

[0319] In some embodiments, all the negative electrode protrusions 122 protrude toward the same side of the negative electrode base 121. Correspondingly, a plurality of support portions 14 are disposed on the same side of the negative electrode base 121.

[0320] The embodiments of this application can simplify the forming process of the negative electrode 12.

[0321] In some embodiments, there are multiple negative electrode protrusions 122, some of which protrude from the negative electrode base 121 at a higher height, while others protrude from the negative electrode base 121 at a lower height. The first support portion includes the negative electrode protrusions 122 at a higher height, and the second support portion includes the negative electrode protrusions 122 at a lower height.

[0322] In some embodiments, the side of the isolator 13 facing the negative electrode recess 123 is provided with a plurality of support portions 14, and at least a portion of the plurality of support portions 14 of the isolator 13 does not overlap with the negative electrode recess 123 in the radial direction.

[0323] In some embodiments, the negative electrode protrusion 122 is formed in the region of the negative electrode sheet 12 where the negative electrode film layer 12b is provided.

[0324] In some embodiments, a gap G is formed between the negative electrode film layer 12b and the positive electrode film layer 11b.

[0325] In some embodiments, the positive electrode 11 has a plurality of support portions 14 on the side facing the separator 13, and the separator 13 has a plurality of support portions 14 on the side facing the positive electrode 11. The plurality of support portions 14 of the positive electrode 11 facing the separator 13 are at least partially opposite to the plurality of support portions 14 of the separator 13 facing the positive electrode 11.

[0326] Optionally, the negative electrode 12 is not provided with a support.

[0327] As an example, both sides of the positive electrode 11 are provided with a separator 13. The separator 13 located inside the positive electrode 11 is called the inner separator, and the separator 13 located outside the positive electrode 11 is called the outer separator.

[0328] In some examples, the positive electrode 11 has a plurality of support portions 14 on the side facing the inner separator, and the inner separator has a plurality of support portions 14 on the side facing the positive electrode 11. The plurality of support portions 14 of the positive electrode 11 and the plurality of support portions 14 of the inner separator are at least partially opposite to each other. For example, the plurality of positive electrode protrusions 112 of the positive electrode 11 are at least partially opposite to the plurality of organic particles of the inner separator.

[0329] In other examples, the positive electrode 11 has a plurality of support portions 14 on the side facing the outer separator, and the outer separator has a plurality of support portions 14 on the side facing the positive electrode 11. The plurality of support portions 14 of the positive electrode 11 and the plurality of support portions 14 of the outer separator are at least partially opposite to each other. For example, the plurality of positive electrode protrusions 112 of the positive electrode 11 are at least partially opposite to the plurality of organic particles of the outer separator.

[0330] In some other examples, multiple support portions 14 are provided on both sides of the positive electrode 11. Multiple support portions 14 are provided on the side of the inner separator facing the positive electrode 11, and multiple support portions 14 are provided on the side of the outer separator facing the positive electrode 11. The multiple support portions 14 of the positive electrode 11 facing the inner separator are at least partially opposite to the multiple support portions 14 of the inner separator facing the positive electrode 11, and the multiple support portions 14 of the positive electrode 11 facing the outer separator are at least partially opposite to the multiple support portions 14 of the outer separator facing the positive electrode 11.

[0331] By arranging the plurality of support portions 14 of the positive electrode 11 and the plurality of support portions 14 of the separator 13 facing each other, the plurality of support portions 14 of the positive electrode 11 and the plurality of support portions 14 of the separator 13 can at least partially abut against each other, thereby increasing the gap G and providing more space for the expansion of the negative electrode 12.

[0332] As an example, embodiments of this application can reduce the depth of the positive electrode recess 113 and the particle size of the organic particles, reduce the damage to the positive electrode sheet 11 during the stamping process, and improve the cycle life of the cylindrical battery cell 7.

[0333] In some embodiments, the negative electrode 12 is provided with a plurality of support portions 14 on the side facing the separator 13, and the separator 13 is provided with a plurality of support portions 14 on the side facing the negative electrode 12. The plurality of support portions 14 of the negative electrode 12 facing the separator 13 are at least partially opposite to the plurality of support portions 14 of the separator 13 facing the negative electrode 12.

[0334] Optionally, the positive electrode 11 is not provided with a support.

[0335] As an example, both sides of the negative electrode 12 are provided with isolation members 13. The isolation member 13 located inside the negative electrode 12 is called the inner isolation member, and the isolation member 13 located outside the negative electrode 12 is called the outer isolation member.

[0336] In some examples, the negative electrode 12 has a plurality of support portions 14 on the side facing the inner separator, and the inner separator has a plurality of support portions 14 on the side facing the negative electrode 12. The plurality of support portions 14 of the negative electrode 12 and the plurality of support portions 14 of the inner separator are at least partially opposite to each other. For example, the plurality of negative electrode protrusions 122 of the negative electrode 12 are at least partially opposite to the plurality of organic particles of the inner separator.

[0337] In other examples, the negative electrode 12 has a plurality of support portions 14 on the side facing the outer separator, and the outer separator has a plurality of support portions 14 on the side facing the negative electrode 12. The plurality of support portions 14 of the negative electrode 12 and the plurality of support portions 14 of the outer separator are at least partially opposite to each other. For example, the plurality of negative electrode protrusions 122 of the negative electrode 12 are at least partially opposite to the plurality of organic particles of the outer separator.

[0338] In some other examples, multiple support portions 14 are provided on both sides of the negative electrode 12. Multiple support portions 14 are provided on the side of the inner separator facing the negative electrode 12, and multiple support portions 14 are provided on the side of the outer separator facing the negative electrode 12. The multiple support portions 14 of the negative electrode 12 facing the inner separator are at least partially opposite to the multiple support portions 14 of the inner separator facing the negative electrode 12, and the multiple support portions 14 of the negative electrode 12 facing the outer separator are at least partially opposite to the multiple support portions 14 of the outer separator facing the negative electrode 12.

[0339] By arranging the plurality of support portions 14 of the negative electrode 12 and the plurality of support portions 14 of the separator 13 facing each other, the plurality of support portions 14 of the negative electrode 12 and the plurality of support portions 14 of the separator 13 can at least partially abut against each other, thereby increasing the gap G and providing more space for the expansion of the negative electrode 12.

[0340] As an example, embodiments of this application can reduce the depth of the negative electrode recess 123 and the particle size of the organic particles P, reduce the damage to the negative electrode sheet 12 during the stamping process, and improve the cycle life of the cylindrical battery cell 7.

[0341] In some embodiments, the negative electrode 12 has a plurality of support portions 14 on the side facing the positive electrode 11, and the positive electrode 11 has a plurality of support portions 14 on the side facing the negative electrode 12. The plurality of support portions 14 of the negative electrode 12 facing the positive electrode 11 are arranged opposite to at least a portion of the plurality of support portions 14 of the positive electrode 11 facing the negative electrode 12.

[0342] Optionally, the isolation element 13 is not provided with a support.

[0343] In some examples, the outer side of the positive electrode 11 is provided with multiple support portions 14, and the inner side of the negative electrode 12 is provided with multiple support portions 14. The multiple support portions 14 on the outer side of the positive electrode 11 and the multiple support portions 14 on the inner side of the negative electrode 12 are arranged facing each other and overlap radially.

[0344] In some examples, the inner side of the positive electrode 11 is provided with multiple support portions 14, and the outer side of the negative electrode 12 is provided with multiple support portions 14. The multiple support portions 14 on the inner side of the positive electrode 11 and the multiple support portions 14 on the outer side of the negative electrode 12 are arranged facing each other and overlap radially.

[0345] In some examples, the positive electrode 11 has multiple support portions 14 on both its inner and outer sides, and the negative electrode 12 has multiple support portions 14 on both its inner and outer sides; the multiple support portions 14 on the outer side of the positive electrode 11 and the multiple support portions 14 on the inner side of the negative electrode 12 are arranged facing each other and overlap radially, and the multiple support portions 14 on the inner side of the positive electrode 11 and the multiple support portions 14 on the outer side of the negative electrode 12 are arranged facing each other and overlap radially.

[0346] By arranging the plurality of support portions 14 of the negative electrode 12 facing each other with the plurality of support portions 14 of the positive electrode 11, the plurality of support portions 14 of the negative electrode 12 and the plurality of support portions 14 of the positive electrode 11 can support each other, thereby increasing the gap G and providing more space for the expansion of the negative electrode 12.

[0347] As an example, embodiments of this application can reduce the depth of the negative electrode recess 123 and the depth of the positive electrode recess 113, reduce the damage to the positive electrode sheet 11 and the negative electrode sheet 12 during the stamping process, and improve the cycle life of the cylindrical battery cell 7.

[0348] In some embodiments, the positive electrode 11, the negative electrode 12, and the separator 13 are each provided with a plurality of support portions 14.

[0349] Optionally, multiple support portions 14 are provided on both sides of the isolation member 13.

[0350] Optionally, the outer side of the positive electrode 11 is provided with a plurality of support portions 14, and the inner side of the negative electrode 12 is provided with a plurality of support portions 14; alternatively, the inner side of the positive electrode 11 is provided with a plurality of support portions 14, and the outer side of the negative electrode 12 is provided with a plurality of support portions 14.

[0351] Figure 15 is a cross-sectional schematic diagram of the positive electrode sheet provided in some other embodiments of this application.

[0352] Referring to FIG15, in some embodiments, the positive electrode 11 includes a positive electrode base 111 and a plurality of support portions 14, the support portions 14 including organic particles disposed on the positive electrode base 111.

[0353] The organic particle P can protrude entirely from the positive electrode base 111. Alternatively, a portion of the organic particle may be embedded in the positive electrode base 111, while another portion protrudes from the positive electrode base 111.

[0354] The organic particles P of the positive electrode 11 can support the negative electrode 12 to increase the gap G and provide space for the expansion of the negative electrode 12.

[0355] In some embodiments, the positive electrode base 111 includes a portion of the positive electrode current collector 11a covered with a positive electrode film layer 11b, the positive electrode film layer 11b, and an inorganic particle layer P3. The positive electrode film layer 11b is disposed on the surface of the positive electrode current collector 11a, and the inorganic particle layer P3 is coated on the surface of the positive electrode film layer 11b facing away from the positive electrode current collector. The organic particles P at least partially protrude from the inorganic particle layer P3.

[0356] The positive electrode film layer 11b includes a positive electrode active material, and the inorganic particle layer P3 includes multiple inorganic particles.

[0357] In some embodiments, a portion of the organic particle P is embedded in the inorganic particle layer P3, and a portion protrudes from the inorganic particle layer P3.

[0358] In some embodiments, the positive electrode 11 includes a positive electrode particle coating 11c disposed on the surface of the positive electrode film layer 11b. The positive electrode particle coating 11c includes an inorganic particle layer P3 and a plurality of organic particles P.

[0359] In some examples, inorganic particles can be coated onto the positive electrode film layer 11b to form an inorganic particle layer P3, and then multiple organic particles can be coated onto the inorganic particle layer P3. In other examples, inorganic and organic particles can be mixed first and then coated together onto the positive electrode film layer 11b.

[0360] As an example, the positive electrode particle coating 11c does not include the positive electrode active material.

[0361] In some embodiments, the plurality of organic particles P includes a first organic particle P1 and a second organic particle P2, wherein the number-average particle size of the first organic particle P1 is greater than the number-average particle size of the second organic particle P2.

[0362] Figure 16 is a cross-sectional schematic diagram of the negative electrode sheet provided in some other embodiments of this application.

[0363] Referring to FIG16, in some embodiments, the negative electrode 12 includes a negative electrode base 121 and a plurality of support portions 14, wherein the support portions 14 include organic particles P disposed on the negative electrode base 121.

[0364] The organic particle P can protrude entirely from the negative electrode base 121. Alternatively, a portion of the organic particle may be embedded in the negative electrode base 121, while another portion protrudes from the negative electrode base 121.

[0365] The organic particles P of the negative electrode 12 can support the positive electrode 11 to increase the gap G and provide space for the expansion of the negative electrode 12.

[0366] In some embodiments, the negative electrode base 121 includes a portion of the negative electrode current collector 12a covered with a negative electrode film layer 12b, the negative electrode film layer 12b, and an inorganic particle layer P3. The negative electrode film layer 12b is disposed on the surface of the negative electrode current collector 12a, and the inorganic particle layer P3 is coated on the surface of the negative electrode film layer 12b facing away from the surface of the negative electrode current collector 12a. The organic particles P at least partially protrude from the inorganic particle layer P3.

[0367] The negative electrode film layer 12b includes a negative electrode active material, and the inorganic particle layer P3 includes multiple inorganic particles.

[0368] In some embodiments, a portion of the organic particle P is embedded in the inorganic particle layer P3, and a portion protrudes from the inorganic particle layer P3.

[0369] In some embodiments, the negative electrode 12 includes a negative electrode particle coating 12c disposed on the surface of the negative electrode film layer 12b. The negative electrode particle coating 12c includes an inorganic particle layer P3 and a plurality of organic particles P.

[0370] In some examples, inorganic particles can be coated onto the negative electrode film layer 12b to form an inorganic particle layer P3, and then multiple organic particles can be coated onto the inorganic particle layer P3. In other examples, inorganic and organic particles can be mixed first and then coated together onto the negative electrode film layer 12b.

[0371] As an example, the negative electrode particle coating 12c does not include the negative electrode active material.

[0372] In some embodiments, the plurality of organic particles P includes a first organic particle P1 and a second organic particle P2, wherein the number-average particle size of the first organic particle P1 is greater than the number-average particle size of the second organic particle P2.

[0373] Figure 17 is a partial cross-sectional view of the electrode assembly of a cylindrical battery cell provided in some other embodiments of this application. Figure 17 shows a ring of positive electrode, a ring of negative electrode, and a ring of separator.

[0374] Referring to Figures 6 and 17, in some embodiments, the radial dimension of the portion of gap G near the winding end E2 is greater than the radial dimension of the portion of gap G near the winding start end E1.

[0375] In the embodiments of this application, the radial dimensions of different portions of the gap G along the winding direction V are compared within the same cross section perpendicular to the axial direction Z.

[0376] As an example, the portion of gap G near the winding end E2 can be: the portion of gap G located inside the winding end E2 and 10mm away from the winding end in the winding direction V; the portion of gap G near the winding start end E1 can be: the portion of gap G located inside the winding start end E1 and 10mm away from the winding start end in the winding direction V.

[0377] There can be one or more gaps G. In the embodiments of this application, the portion of gap G near the winding end E2 and the portion of gap G near the winding start end E1 refer to the same gap G.

[0378] As an example, the radial dimension of the portion of gap G near the winding start end E1 can be equal to the sum of the radial dimension of the portion of the first gap G1 near the winding start end E1 and the radial dimension of the portion of the second gap G2 near the winding start end E1.

[0379] As an example, the radial dimension of the portion of gap G near the winding end E2 can be equal to the sum of the radial dimension of the portion of the first gap G1 near the winding end E2 and the radial dimension of the portion of the second gap G2 near the winding end E2.

[0380] During the cycling process of the cylindrical battery cell 7, the expansion of the negative electrode 12 gradually accumulates radially from the inside to the outside. In the embodiments of this application, the portion of the gap G near the winding end E2 has a larger radial dimension to provide more expansion space for the negative electrode 12, absorb the accumulated expansion of the negative electrode 12, thereby reducing the force between the electrode assembly 10 and the housing 20, reducing the deformation of the housing 20, reducing the risk of cracking of the housing 20, and improving reliability.

[0381] In some embodiments, the gap G is wound along the winding direction V to form n winding loops, where n ≥ 20 and n is a natural number. The innermost winding loop is the first winding loop.

[0382] For example, the first winding loop includes a winding start end E1; the first winding loop extends one revolution from the winding start end E1 along the winding direction V.

[0383] For example, the nth winding loop includes a winding termination end E2; the nth winding loop extends from the end of the (n-1)th winding loop along the winding direction V to the winding termination end E2.

[0384] For example, the first to n-1 windings are all full turns; the nth winding can be a full turn or not a full turn, for example, the nth winding is 1 / 4 turn, 1 / 2 turn or 3 / 4 turn.

[0385] For example, n is 20, 30, 40, 50, 60, 70, 80, 90, 100, 150 or 200.

[0386] In some embodiments, there are two gaps G, which are respectively disposed on both sides of the positive electrode 11. For example, the gap G located on the inner side of the positive electrode 11 can be defined as the inner gap, and the gap G located on the outer side of the positive electrode 11 can be defined as the outer gap.

[0387] The inner gap is wound along the winding direction V to form n winding loops, and the outer gap is wound along the winding direction V to form n winding loops.

[0388] The q-th winding of the outer gap is located outside the q-th winding of the inner gap, and inside the (q+1)-th winding of the inner gap, where 1 ≤ q ≤ n-1. The n-th winding of the outer gap is located outside the n-th winding of the inner gap.

[0389] In some embodiments, the radial dimension of the kth winding is less than the radial dimension of the (k+10)th winding, where k is a natural number and 5≤k≤n-15.

[0390] In the 5th to n-15th windings, any one of the windings satisfies the aforementioned relationship. For example, the radial dimension of the 5th winding is smaller than the radial dimension of the 15th winding, the radial dimension of the 6th winding is smaller than the radial dimension of the 16th winding, ..., the radial dimension of the n-16th winding is smaller than the radial dimension of the n-6th winding, and the radial dimension of the n-15th winding is smaller than the radial dimension of the n-5th winding.

[0391] In this embodiment of the application, the kth winding and the (k+10th)th winding are two windings with the same gap G.

[0392] In this embodiment, the radial dimension of the kth winding and the (k+10th)th winding are compared within the same cross section perpendicular to the axial direction Z.

[0393] The (k+10)th winding is positioned further outward than the kth winding, and the radial dimension of the (k+10)th winding is larger than that of the kth winding. The (k+10)th winding can provide more expansion space for the negative electrode film layer of the inner negative electrode sheet 12, absorb the accumulated expansion of the negative electrode sheet 12, thereby reducing the interaction force between the electrode assembly 10 and the housing 20, reducing the deformation of the housing 20, reducing the risk of cracking of the housing 20, and improving reliability.

[0394] In some embodiments, the gap G is wound along the winding direction V to form n winding loops, where n ≥ 20 and n is a natural number. The innermost winding loop is the first winding loop. The average radial dimension of the (n-9)th to (n-5)th winding loops is greater than the average radial dimension of the 5th to 9th winding loops.

[0395] In the embodiments of this application, the gap G can be one or two. The (n-9)th to (n-5)th winding turns and the 5th to 9th winding turns all belong to the same gap G.

[0396] In the embodiments of this application, the radial dimensions of the (n-9) to (n-5)th windings and the radial dimensions of the 5th to 9th windings are measured and calculated in the same cross section perpendicular to the axial direction Z.

[0397] The portion of gap G near the winding end E2 has a larger radial dimension to provide more expansion space for the negative electrode 12, absorb the accumulated expansion of the negative electrode 12, thereby reducing the force between the electrode assembly 10 and the housing 20, reducing the deformation of the housing 20, reducing the risk of cracking of the housing 20, and improving reliability.

[0398] In some embodiments, the radial dimension of at least a portion of the gap G gradually increases along the winding direction V.

[0399] The radial dimension of the gap G changes gradually, reducing abrupt changes in the radial dimension of the gap G, reducing stress concentration in the negative electrode 12, and improving the cycle performance of the cylindrical battery cell 7.

[0400] In some embodiments, the radial dimensions of the gap G at various locations can be adjusted by changing the height of the support 14.

[0401] Figure 18 is a partial cross-sectional view of the electrode assembly of a cylindrical battery cell provided in some other embodiments of this application.

[0402] Referring to FIG18, in some embodiments, the electrode assembly 10 includes a central region C1 and two end regions C2 arranged along the axial direction Z of the cylindrical battery cell, with the central region C1 located between the two end regions C2. The radial dimension of the portion of the gap G located in the central region C1 is smaller than the radial dimension of the portion of the gap G located in the end regions C2.

[0403] As an example, the separator 13 has a first end E7 and a second end E8 disposed opposite each other along the axial direction Z; the distance between the first end E7 and the second end E8 in the axial direction Z is L.

[0404] The end region C2 is a region with a certain size along the axial direction Z. One end region C2 extends from the first end E7 toward the second end E8 to a length L1, and the other end region C2 extends from the second end E8 toward the first end E7 to a length L1. The middle region C1 includes a region extending from the mid-section S toward the first end E7 to a length L2 and a region extending from the mid-section S toward the second end E8 to a length L2. The mid-section S is a section perpendicular to the axial direction Z; along the axial direction Z, the distance between the mid-section S and the first end E7 is equal to the distance between the mid-section S and the second end E8.

[0405] A portion of the positive electrode film is located in the central region C1, and another portion is located in the end region C2.

[0406] For example, L1 / L is 0.1-0.3, and can be 0.2. For example, L2 / L is 0.03-0.2, and can be 0.1.

[0407] For example, L1 can be 20mm and L2 can be 5mm.

[0408] As an example, the radial dimensions of the portion of gap G located in the middle region C1 and the radial dimensions of the portion of gap G located in the end region C2 can be measured in the following manner:

[0409] Using CT (Computed Tomography) technology, images of two cross-sections of a cylindrical battery cell are obtained using X-rays. Both cross-sections are perpendicular to the axis of the cylindrical battery cell, and each cross-section shows the positive electrode film, the negative electrode film, and the separator. One cross-section passes through the middle region C1 of the electrode assembly, and the other cross-section passes through the end region C2 of the 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.

[0410] Based on the image of the first cross section, a first virtual straight line is defined, which can pass through the center of the first cross section;

[0411] Based on the image of the first cross section and the first virtual line, along a direction away from the center of the first cross section and parallel to the first virtual line, the third intersection point of the outer surface of the 6th layer positive electrode and the first virtual line is obtained, and the fourth intersection point of the inner surface of the 10th layer positive electrode and the first virtual line is obtained. The distance D2 between the third intersection point and the fourth intersection point is measured. Wherein, if the positive electrode is provided with a support, the third intersection point is formed at the position where the support is not provided on the outer surface of the 6th layer positive electrode, and the fourth intersection point is formed at the position where the support is not provided on the inner surface of the 10th layer positive electrode.

[0412] Based on the image of the second cross section, a second virtual straight line is defined, which can pass through the center of the second cross section;

[0413] Based on the image of the second cross section and the second virtual line, along a direction away from the center of the second cross section and parallel to the second virtual line, obtain the fifth intersection point between the outer surface of the 6th layer positive electrode and the second virtual line, obtain the sixth intersection point between the inner surface of the 10th layer positive electrode and the second virtual line, and measure the distance D3 between the fifth and sixth intersection points; if the positive electrode has a support portion, the fifth intersection point is formed at the position where the support portion is not provided on the outer surface of the 6th layer positive electrode, and the sixth intersection point is formed at the position where the support portion is not provided on the inner surface of the 10th layer positive electrode;

[0414] Disassemble the cylindrical battery cell and unfold the positive electrode, negative electrode, and separator;

[0415] In the portion of the positive electrode where no support is provided, 50 locations are randomly selected, and 50 thickness values ​​are measured. The average value of the 50 thickness values ​​is then calculated, and this average value can be used as t1.

[0416] In the part of the negative electrode sheet where no support is provided, 50 positions are randomly selected, 50 thickness values ​​are measured, and then the average value of the 50 thickness values ​​is calculated. This average value can be used as t2.

[0417] In the unsupported portion of the isolation component, 50 locations are randomly selected, and 50 thickness values ​​are measured. The average value of the 50 thickness values ​​is then calculated, and this average value can be used as t3.

[0418] Between the outer surface of the 6th positive electrode layer and the inner surface of the 10th positive electrode layer, there are 3 positive electrode layers, 4 negative electrode layers, and 8 separators; 8 gaps are formed between the outer surface of the 6th positive electrode layer and the inner surface of the 10th positive electrode layer.

[0419] The radial dimension of the portion of gap G located in the middle region C1 can be (D2-3×t1-4×t2-8×t3) / 8. The radial dimension of the portion of gap G located in the end region C2 can be (D3-3×t1-4×t2-8×t3) / 8.

[0420] In this embodiment, the gap G has a larger radial dimension in the end region C2 to facilitate the entry of electrolyte into the gap G, improve the wetting effect of electrolyte on the electrode, and enhance the cycle performance of the cylindrical battery cell 7.

[0421] In some embodiments, the radial dimension of the portion of the gap G located in the central region is 5 μm-60 μm, and optionally 10 μm-30 μm.

[0422] In some embodiments, the electrode assembly 10 further includes a transition region C3 connecting the central region C1 and the end region C2.

[0423] In some embodiments, the radial dimension of the gap G decreases in the direction from the two end regions C2 to the middle region C1, so as to reduce the abrupt change in the radial dimension of the gap G, reduce the stress concentration of the negative electrode 12, and improve the cycle performance of the cylindrical battery cell 7.

[0424] In some embodiments, the radial dimension of the gap G in each region can be adjusted by changing the height of the support 14.

[0425] Figure 19 is a partial cross-sectional schematic diagram of the electrode assembly of a cylindrical battery cell provided in some other embodiments of this application; Figure 20 is a schematic diagram of the positive electrode sheet of a cylindrical battery cell provided in some other embodiments of this application in an unfolded state; Figure 21 is a schematic diagram of the negative electrode sheet of a cylindrical battery cell provided in some other embodiments of this application in an unfolded state.

[0426] In some embodiments, the positive electrode 11 has a positive electrode recess 113 on the side facing the separator 13.

[0427] The positive electrode recess 113 can be one or more.

[0428] For example, the positive electrode 11 has a separator 13 on both sides along its thickness direction. Optionally, the positive electrode 11 has a positive electrode recess 113 on one side along its thickness direction; alternatively, the positive electrode 11 has a positive electrode recess 113 on both sides along its thickness direction.

[0429] For example, in the thickness direction of the positive electrode sheet 11, the depth of the positive electrode recess 113 is less than or equal to the thickness of the positive electrode film layer 11b. The thickness of the positive electrode film layer 11b is the thickness of the positive electrode film layer 11b located on one side of the positive electrode current collector 11a.

[0430] By providing the positive electrode recess 113, the gap between the positive electrode 11 and the negative electrode 12 can be increased. During the cycling process of the cylindrical battery cell 7, the positive electrode recess 113 can provide space for the expansion of the negative electrode film layer 12b, reducing the pressure between the positive electrode 11 and the negative electrode 12. This reduces the compression of the electrolyte in the internal pores of the positive electrode film layer 11b and the internal pores of the negative electrode film layer 12b, reduces the concentration difference of electrolyte in different regions inside the electrode, and improves the cycling performance of the cylindrical battery cell 7 with a larger diameter. The positive electrode recess 113 can reduce the expansion of the electrode assembly 10, thereby reducing the compression effect on the casing 20, reducing the risk of deformation and cracking of the casing 20, and improving the reliability of the cylindrical battery cell 7.

[0431] The positive electrode recess 113 can also accommodate electrolyte, which helps the electrolyte to wet the positive electrode 11 and the negative electrode 12.

[0432] In some embodiments, the gap G includes a positive electrode recess 113.

[0433] In some embodiments, the positive electrode 11 does not have a protruding support portion.

[0434] In some embodiments, the positive electrode 11 does not have a positive electrode protrusion at the position corresponding to the positive electrode recess 113.

[0435] In some embodiments, the positive electrode 11 includes a positive electrode film 11b, and a positive electrode recess 113 is formed on the positive electrode film 11b, which can reduce the influence of the positive electrode recess 113 on the flow capacity of the positive electrode current collector 11a.

[0436] In some embodiments, the depth of the positive electrode recess 113 is less than the thickness of the positive electrode film 11b in the thickness direction of the positive electrode sheet 11. Optionally, the ratio of the depth of the positive electrode recess 113 to the thickness of the positive electrode film 11b in the thickness direction of the positive electrode sheet 11 is 0.01-0.5.

[0437] In some embodiments, the positive electrode recess 113 extends through the positive electrode film layer 11b along the axial direction Z of the cylindrical battery cell to increase the gap between the positive electrode sheet 11 and the negative electrode sheet 12 and improve the wettability of the electrolyte.

[0438] In some embodiments, the positive electrode recess 113 extends along the axial direction Z.

[0439] In some embodiments, the cross-section of the positive electrode recess 113 perpendicular to the axial direction Z is triangular, trapezoidal, semi-circular, or other shapes.

[0440] In some embodiments, there are multiple positive electrode recesses 113.

[0441] In some embodiments, at least a portion of the plurality of positive electrode recesses 113 are disposed on the inner side of the positive electrode sheet 11. The inner side of the positive electrode sheet 11 has a large curvature. Disposing the positive electrode recesses 113 on the inner side of the positive electrode sheet 11 can release stress and reduce the risk of positive electrode active material in the positive electrode film layer 11b falling off.

[0442] In addition, by placing the positive electrode recess 113 inside the positive electrode sheet 11, the capacity of the positive electrode film layer 11b inside the positive electrode sheet 11 can be reduced, thereby reducing the risk of ion deposition in the negative electrode film layer 12b located inside the positive electrode film layer 11b.

[0443] In some embodiments, at least a portion of the plurality of positive electrode recesses 113 are disposed on the outer side of the positive electrode sheet 11.

[0444] In some embodiments, the positive electrode 11 includes a plurality of positive electrode recesses 113 spaced apart along the winding direction V. The plurality of positive electrode recesses 113 can provide space for expansion of different regions of the negative electrode film 12b, reducing the pressure between the positive electrode 11 and the negative electrode 12.

[0445] In some embodiments, the negative electrode sheet 12 has a negative electrode recess 123 on the side facing the separator 13.

[0446] The negative electrode recess 123 can be one or more.

[0447] For example, the negative electrode 12 has a separator 13 on both sides along its thickness direction. Optionally, the negative electrode 12 has a negative electrode recess 123 on one side along its thickness direction; alternatively, the negative electrode 12 has negative electrode recesses 123 on both sides along its thickness direction.

[0448] For example, in the thickness direction of the negative electrode sheet 12, the depth of the negative electrode recess 123 is less than or equal to the thickness of the negative electrode film layer 12b. The thickness of the negative electrode film layer 12b is the thickness of the negative electrode film layer 12b located on one side of the negative electrode current collector 12a.

[0449] By providing the negative electrode recess 123, the gap between the positive electrode 11 and the negative electrode 12 can be increased. During the cycling process of the cylindrical battery cell 7, the negative electrode recess 123 can provide space for the expansion of the negative electrode film layer 12b, reducing the pressure between the positive electrode 11 and the negative electrode 12. This reduces the compression of the electrolyte in the internal pores of the positive electrode film layer 11b and the internal pores of the negative electrode film layer 12b, reduces the concentration difference of electrolyte in different regions inside the electrode, and improves the cycling performance of the cylindrical battery cell 7 with a larger diameter. The negative electrode recess 123 can reduce the expansion of the electrode assembly 10, thereby reducing the compression effect on the casing 20, reducing the risk of deformation and cracking of the casing 20, and improving the reliability of the cylindrical battery cell 7.

[0450] The negative electrode recess 123 can also accommodate electrolyte, which helps the electrolyte wet the positive electrode 11 and the negative electrode 12.

[0451] In some embodiments, the gap includes a negative electrode recess 123.

[0452] In some embodiments, the negative electrode 12 includes a negative electrode film layer 12b, and a negative electrode recess 123 is formed in the negative electrode film layer 12b, which can reduce the influence of the negative electrode recess 123 on the flow capacity of the negative electrode current collector 12a. The negative electrode recess 123 can provide space for the expansion of the negative electrode film layer 12b.

[0453] In some embodiments, the negative electrode 12 does not have a protruding support portion.

[0454] In some embodiments, the negative electrode sheet 12 does not have a negative electrode protrusion at the position corresponding to the negative electrode recess 123.

[0455] In some embodiments, the depth of the negative electrode recess 123 is less than the thickness of the negative electrode 12 in the thickness direction of the negative electrode 12. Optionally, the ratio of the depth of the negative electrode recess 123 to the thickness of the negative electrode 12 in the thickness direction of the negative electrode 12 is 0.01-0.5.

[0456] In some embodiments, the negative electrode recess 123 extends through the negative electrode film layer 12b along the axial direction Z of the cylindrical battery cell to increase the gap between the positive electrode 11 and the negative electrode 12 and improve the wettability of the electrolyte.

[0457] In some embodiments, the negative electrode recess 123 extends along the axial direction Z.

[0458] In some embodiments, the cross-section of the negative electrode recess 123 perpendicular to the axial direction Z is triangular, trapezoidal, semi-circular, or other shapes.

[0459] In some embodiments, there are multiple negative electrode recesses 123.

[0460] In some embodiments, at least a portion of the plurality of negative electrode recesses 123 are disposed on the inner side of the negative electrode sheet 12. The inner side of the negative electrode sheet 12 has a large curvature. Disposing the negative electrode recesses 123 on the inner side of the negative electrode sheet 12 can release stress and reduce the risk of negative electrode active material in the negative electrode film layer 12b falling off.

[0461] In some embodiments, at least a portion of the plurality of negative electrode recesses 123 are disposed on the outer side of the negative electrode sheet 12.

[0462] In some embodiments, the negative electrode 12 includes a plurality of negative electrode recesses 123 spaced apart along the winding direction V. The plurality of negative electrode recesses 123 can provide space for expansion of different regions of the negative electrode film layer 12b, reducing the pressure between the positive electrode 11 and the negative electrode 12.

[0463] Figure 22 is a cross-sectional view of the battery cell shown in Figure 4; Figure 23 is an enlarged view of Figure 22 at the circular frame.

[0464] Referring to Figures 4, 5, 22, and 23, in some embodiments, one of the positive electrode 11 and the negative electrode 12 includes a first tab 10a, and the other includes a second tab 10b. In other words, one of the first tab 10a and the second tab 10b is a positive tab, and the other is a negative tab.

[0465] The first tab 10a and the second tab 10b can be located at the same end of the electrode assembly 10 along the axial direction Z, or they can be located at opposite ends of the electrode assembly 10 along the axial direction Z.

[0466] In some embodiments, the portion of the positive electrode 11 having a positive electrode film layer, the portion of the negative electrode 12 having a negative electrode film layer, and the separator 13 constitute the electrode body 10c of the electrode assembly 10. The first tab 10a and the second tab 10b are led out from one end of the electrode body 10c, or from both ends of the electrode body 10c respectively.

[0467] In some embodiments, the first tab 10a is wound multiple turns along the winding direction V. Optionally, the end of the first tab 10a is bent by a flattening or smoothing process to form a multi-layered structure stacked in the axial direction Z.

[0468] In some embodiments, the second electrode tab 10b is wound 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 multi-layered structure stacked in the axial direction Z.

[0469] 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 tab 10a, and the second electrode lead 7b is electrically connected to a second tab 10b. The first electrode lead 7a and the second electrode lead 7b are insulated from each other.

[0470] The first electrode lead-out portion 7a and the second electrode lead-out portion 7b are used to connect to an external circuit to enable charging or discharging of the cylindrical battery cell 7. Exemplarily, when multiple cylindrical battery cells 7 are assembled into a group, the first electrode lead-out portion 7a and the second electrode lead-out portion 7b are used to connect to a busbar component.

[0471] The first electrode lead-out portion 7a can be an electrode terminal 30 disposed on the housing 20. The electrode terminal 30 is formed independently of the housing 20 and is assembled together during the production process of the cylindrical battery cell 7. As an example, the electrode terminal 30 is insulatedly disposed on the end cap 22 or the housing 21.

[0472] Alternatively, the first electrode lead-out portion 7a may also be part of the housing 20. For example, the first electrode lead-out portion 7a may be the end cap 22 of the housing 20, or the first electrode lead-out portion 7a may be the end wall 211 of the housing 21 opposite to the end cap 22.

[0473] The second electrode lead-out portion 7b can be an electrode terminal 30 disposed on the housing 20. Alternatively, the second electrode lead-out portion 7b can be part of the housing 20. For example, the second electrode lead-out portion 7b can be an end cap 22 of the housing 20, or the second electrode lead-out portion 7b can be an end wall 211 of the housing 21 opposite to the end cap 22.

[0474] In some embodiments, the first electrode lead-out portion 7a and the second electrode lead-out portion 7b are located on the same side of the electrode assembly 10 along the axial Z direction of the cylindrical battery cell.

[0475] When multiple cylindrical battery cells 7 are assembled into a group, the first electrode lead-out portion 7a and the second electrode lead-out portion 7b of the multiple cylindrical battery cells 7 can be arranged on the same side, which facilitates the connection between the current collector and the first electrode lead-out portion 7a and the second electrode lead-out portion 7b, and simplifies the battery structure.

[0476] In some embodiments, the housing 20 includes a housing 21 and an end cap 22. The housing 21 includes a side wall 212 and an end wall 211. The end wall 211 and the end cap 22 are opposite each other along the axial direction Z of the cylindrical battery cell, and the end cap 22 is sealed to the side wall 212.

[0477] The sidewall 212 and the endwall 211 can be formed integrally or independently. For example, the sidewall 212 and the endwall 211 can be formed integrally. Alternatively, the sidewall 212 and the endwall 211 can be formed independently and connected by welding or other means.

[0478] The end cap 22 can be insulated from the side wall 212 or electrically connected.

[0479] The end of the housing 21 away from the end wall 211 has an opening, and the end cap 22 covers the opening of the housing 21.

[0480] In some embodiments, the sidewall 212 and the endwall 211 may be integrally formed.

[0481] In some embodiments, one of the positive electrode 11 and the negative electrode 12 includes a first tab 10a, and the other includes a second tab 10b. The cylindrical battery cell 7 also includes an electrode terminal 30 insulated on the end wall 211, one of the first tab 10a and the second tab 10b being electrically connected to the electrode terminal 30, and the other being electrically connected to the end wall 211.

[0482] As an example, the first tab 10a is electrically connected to the electrode terminal 30, and the second tab 10b is electrically connected to the end wall 211. The second tab 10b can be directly connected to the end wall 211, or it can be indirectly connected to the end wall 211 through the end cap 22, the side wall 212, or other components.

[0483] One of the electrode terminal 30 and the end wall 211 serves as the first electrode lead-out portion 7a, and the other serves as the second electrode lead-out portion 7b.

[0484] The electrode terminal 30 and the end wall 211 can serve as two exposed electrodes of the cylindrical battery cell 7. The electrode terminal 30 and the end wall 211 are located on the same side, which is beneficial for assembling multiple cylindrical battery cells 7 into a group and simplifies the battery structure.

[0485] In some embodiments, the cylindrical battery cell 7 further includes a first current collector 40, which is located on the side of the first tab 10a facing the end wall 211 and connected to the first tab 10a. The electrode terminal 30 abuts against and is connected to the surface of the first current collector 40 facing the end wall 211.

[0486] The first current collector 40 can act as a converter to realize the electrical connection between the first tab 10a and the electrode terminal 30.

[0487] In some embodiments, the first current collector 40 is annular.

[0488] In some embodiments, the electrode terminal 30 has a terminal recess 31 on the side facing the first current collector 40, and the bottom wall of the terminal recess 31 is welded to the first current collector 40.

[0489] By providing the terminal recess 31, the thickness of the bottom wall of the terminal recess 31 can be reduced, the power required to weld the electrode terminal 30 to the first current collector 40 from the outside can be reduced, the risk of welding particles falling into the casing 20 can be reduced, and the reliability of the cylindrical battery cell 7 can be improved.

[0490] By placing the terminal recess 31 inside the electrode terminal 30, the internal space of the cylindrical battery cell 7 can be increased.

[0491] In some embodiments, the electrode terminal 30 has a terminal recess 31 on the side opposite to the first current collector 40.

[0492] In some embodiments, the electrode terminal 30 has a terminal recess 31 on the side facing the first current collector 40, and another terminal recess 31 on the side of the electrode terminal 30 away from the first current collector 40; the corresponding portions of the bottom surfaces of the two terminal recesses 31 are welded to the first current collector 40.

[0493] In some embodiments, the bottom wall of the terminal recess 31 is provided with a through hole 32, which can be used to inject electrolyte.

[0494] In some embodiments, the cylindrical battery cell 7 further includes a cover plate 50, which is connected to the electrode terminal 30 and serves to separate the through hole 32 from the external space of the cylindrical battery cell 7.

[0495] In some embodiments, at least a portion of the cover plate 50 is received within the terminal recess 31. In some embodiments, the first electrode lead-out portion includes the cover plate 50 and the electrode terminal 30.

[0496] In some embodiments, the electrode terminal 30 is riveted to the end wall 211.

[0497] In some embodiments, a first tab 10a is located at one end of the electrode assembly 10 facing the end wall 211, and a second tab 10b is located at one end of the electrode assembly 10 facing the end cap 22. The cylindrical battery cell 7 also includes a second current collector 60 connected to the second tab 10b; the second current collector 60 is connected to at least one of the end cap 22 and the side wall 212.

[0498] In some examples, the second current collector 60 is connected to the end cap 22, which is electrically connected to the side wall 212. The second tab 10b is electrically connected to the end wall 211 via the second current collector 60, the end cap 22, and the side wall 212.

[0499] In other examples, the second current collector 60 is connected to the sidewall 212. The second tab 10b is electrically connected to the end wall 211 via the second current collector 60 and the sidewall 212. Optionally, the end cap 22 is insulated from the sidewall 212.

[0500] In some embodiments, the housing 20 includes a sidewall 212 surrounding the electrode assembly 10, the sidewall 212 having a thickness of 0.3 mm to 1.5 mm. The sidewall 212 is made of steel.

[0501] As an example, the thickness of the sidewall 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.

[0502] In the embodiments of this application, the thickness of the sidewall 212 has a meaning known in the art and can be detected using equipment and methods known in the art, such as a micrometer or vernier caliper.

[0503] As an example, the material of sidewall 212 includes stainless steel.

[0504] By setting a gap G, this application can reduce the expansion force exerted by the electrode assembly 10 on the sidewall 212. Therefore, the steel sidewall 212 can have a thickness of less than or equal to 1.5 mm, thereby increasing the energy density of the cylindrical battery cell 7. The thickness of the steel sidewall 212 is greater than or equal to 0.3 mm to reduce the risk of deformation and breakage of the sidewall 212 under the expansion force of the electrode assembly 10, thereby improving the reliability of the cylindrical battery cell 7.

[0505] The sidewall 212 has relatively high mechanical strength and is not easily deformed. When used in conjunction with the silicon-containing negative electrode 12, it is more conducive to improving the energy density of the cylindrical battery cell and giving the cylindrical battery cell excellent reliability.

[0506] In some embodiments, the thickness of the sidewall 212 is 0.3 mm to 1.2 mm.

[0507] In some embodiments, the thickness of the sidewall 212 is 0.3 mm to 0.9 mm, optionally 0.3 mm to 0.6 mm.

[0508] In some embodiments, the areal density of the negative electrode is greater than or equal to 3.2 mAh / cm³. 2 The substrate material of the sidewall 212 includes steel, and the thickness of the sidewall 212 is 0.3 mm to 0.9 mm. The above-mentioned negative electrode sheet with the above-mentioned areal density and the sidewall 212 with the above-mentioned thickness are used together to improve the energy density of the cylindrical battery cell 7, while giving the cylindrical battery cell 7 excellent reliability and improving cycle performance.

[0509] In some embodiments, the end wall 211 is made of the same material as the side wall 212.

[0510] In some embodiments, the end cap 22 is made of steel.

[0511] In some embodiments, the height of the housing 20 is 1.3 to 4 times the diameter of the housing 20. Exemplarily, the height of the housing 20 may be the dimension of the housing 20 along the axial direction Z.

[0512] Optionally, the height of the outer casing 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 outer casing 20.

[0513] When the housing 20 meets the above-mentioned size requirements, the structural stability of the housing 20 is high, which can improve the reliability of the cylindrical battery cell 7.

[0514] In some embodiments, the height of the housing 20 is 1.5 to 2.5 times the diameter of the housing 20.

[0515] 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.

[0516] Optionally, the height of the housing 20 is 60mm-100mm.

[0517] 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.

[0518] Optionally, the diameter of the housing 20 is 45 mm to 60 mm.

[0519] Figure 24 is a partial cross-sectional schematic diagram of a battery cell provided in some other embodiments of this application.

[0520] Referring to FIG24, in some embodiments, both the first tab 10a and the second tab 10b are located at the end of the electrode assembly 10 facing the end wall 211. The first tab 10a and the second tab 10b can share space in the axial Z direction, thereby improving space utilization and increasing energy density.

[0521] In some embodiments, the cylindrical battery cell 7 includes two electrode terminals 30 disposed on the end wall 211, and a first tab 10a and a second tab 10b are electrically connected to the two electrode terminals 30, respectively. The two electrode terminals 30 are a first electrode lead-out portion 7a and a second electrode lead-out portion 7b, respectively.

[0522] Optionally, the cylindrical battery cell 7 includes a first current collector 40 and a second current collector 60. The first current collector 40 is connected to a first tab 10a and an electrode terminal 30, and the second current collector 60 is connected to a second tab 10b and another electrode terminal 30.

[0523] In other embodiments, the cylindrical battery cell includes an electrode terminal disposed on the end wall, a first tab electrically connected to the electrode terminal, and a second tab electrically connected to the end wall.

[0524] In some embodiments, the projection of the first tab 10a along the axial direction Z is a fan shape.

[0525] In some embodiments, the projection of the second tab 10b along the axial direction Z is fan-shaped.

[0526] Figure 25 is a partial cross-sectional schematic diagram of a cylindrical battery cell provided in some other embodiments of this application.

[0527] Referring to FIG25, in some embodiments, the sidewall 212 is provided with an inwardly protruding protrusion 2121.

[0528] For example, the protrusion 2121 can be a solid structure or a hollow structure.

[0529] In some embodiments, at least a portion of the protrusion 2121 is located between the end cap 22 and the second tab 10b in the axial direction Z.

[0530] The protrusion 2121 overlaps with the second tab 10b in the axial direction Z. When the cylindrical battery cell 7 is subjected to external impact, it can restrict the movement of the second tab 10b in the axial direction Z and reduce the risk of failure of the connection between the second tab 10b and the second current collector 60.

[0531] In some embodiments, the second current collector 60 is connected to the protrusion 2121. As an example, the second current collector 60 may be welded to the protrusion 2121; alternatively, the second current collector 60 may also be press-fitted to the protrusion 2121.

[0532] For example, the second current collector 60 is connected to the side of the protrusion 2121 facing the second electrode 10b, or it can be connected to the side of the protrusion 2121 facing the end cap 22.

[0533] Connecting the second current collector 60 to the protrusion 2121 can shorten the conductive path between the second tab 10b and the end wall 211, reduce resistance, reduce heat generation, and improve the cycle performance of the cylindrical battery cell 7.

[0534] In some embodiments, a portion of the second current collector 60 is located on the side of the protrusion 2121 facing the end cap 22 and is connected to the protrusion 2121. The second current collector 60 is connected to the protrusion 2121 from the outside of the protrusion 2121, which can reduce assembly difficulty.

[0535] In some embodiments, the second current collector 60 is welded to the protrusion 2121.

[0536] In some embodiments, the outer side of the sidewall 212 is provided with a recess 2122, which corresponds to the position of the protrusion 2121. As an example, after the electrode assembly 10 is installed into the housing 21, the sidewall 212 is pressed from the outside to form an inwardly protruding protrusion 2121.

[0537] In some embodiments, the sidewall 212 further includes a crimping portion 2123, which extends from the end of the protrusion 2121 away from the endwall 211 and surrounds the end cap 22.

[0538] A portion of the crimping part 2123 is bent to form a flange structure, and a portion of the end cap 22 is located between the flange structure and the protrusion 2121 in the axial direction Z. The protrusion 2121 and the flange structure can limit the end cap 22 to fix the end cap 22 in the axial direction Z.

[0539] In some embodiments, the cylindrical battery cell 7 further includes an insulating member 70, which is disposed between the sidewall 212 and the end cap 22 and insulates the end cap 22 from the sidewall 212.

[0540] In some embodiments, a portion of the insulating member 70 is located between the second current collector 60 and the end cap 22 to insulate the second current collector 60 from the end cap 22.

[0541] According to some embodiments of this application, this application also provides a battery comprising a plurality of cylindrical battery cells 7 according to any of the above embodiments.

[0542] According to some embodiments of this application, this application also provides an electrical device, including a cylindrical battery cell 7 of any of the above embodiments, wherein the cylindrical battery cell 7 is used to provide electrical energy to the electrical device. The electrical device can be any of the aforementioned devices or systems that utilize the cylindrical battery cell 7.

[0543] Referring to Figures 4 to 9, this application embodiment provides a cylindrical battery cell 7, which includes a housing 20, an electrode assembly 10, electrode terminals 30, a first current collector 40, and a second current collector 60.

[0544] The outer casing 20 includes a housing 21 and an end cap 22. The housing 21 includes an integrally formed side wall 212 and an end wall 211. The end wall 211 and the end cap 22 are opposite each other along the axial direction Z of the cylindrical battery cell. The end cap 22 is welded to the side wall 212.

[0545] Electrode terminals 30 are insulatedly disposed on end wall 211.

[0546] At least a portion of the electrode assembly 10 is housed within the housing 20. The electrode assembly 10 includes a positive electrode 11, a negative electrode 12, and a separator 13, which are wound together, with the separator 13 separating the positive electrode 11 and the negative electrode 12.

[0547] The positive electrode 11 has a first tab 10a at one end facing the end wall 211, and the first current collector 40 connects the electrode terminal 30 and the first tab 10a. The negative electrode 12 has a second tab 10b at one end facing the end cover 22, and the second current collector 60 connects the first tab 10a and the end cover 22.

[0548] The separator 13 includes a base film 13a and a coating 13b disposed on at least one surface of the base film 13a. The coating 13b includes an inorganic particulate layer P3 and a plurality of organic particles P, the organic particles P at least partially protruding from the inorganic particulate layer P3, the organic particles P serving to support the positive electrode 11 or the negative electrode 12 to form a gap G between the positive electrode 11 and the negative electrode 12.

[0549] Example

[0550] The following embodiments describe the contents disclosed in this application in more detail. These embodiments are merely illustrative, as various modifications and variations will be apparent to those skilled in the art within the scope of the disclosures in this application. Unless otherwise stated, all parts, percentages, and ratios reported in the following embodiments are based on mass, and all reagents used in the embodiments are commercially available or synthesized by conventional methods and can be used directly without further processing, and the instruments used in the embodiments are commercially available.

[0551] Example 1

[0552] 1. Preparation of positive electrode sheet

[0553] The positive electrode sheet includes a positive current collector and a positive electrode film layer. The positive electrode film layer is located on both sides of the positive current collector. The positive current collector is an aluminum foil. The positive electrode film layer is formed by uniformly coating the surface of the positive current collector aluminum foil with a positive electrode slurry (solvent is N-methylpyrrolidone NMP), and then drying and cold pressing it. The positive electrode film layer includes positive active material, conductive agent carbon black (Super P), and binder polyvinylidene fluoride (PVDF) in a weight ratio of 97:1:2.

[0554] Positive electrode active materials include those with the molecular formula LiNi 0.8 Co 0.1 Mn 0.1 O2 (NCM811) is a layered transition metal oxide.

[0555] 2. Preparation of negative electrode sheet

[0556] The negative electrode sheet includes a negative electrode current collector and a negative electrode film layer. The negative electrode film layer is located on both sides of the negative electrode current collector. The negative electrode current collector is a copper foil. The negative electrode film layer is formed by uniformly coating a negative electrode slurry (the solvent is deionized water) onto the surface of the copper foil of the negative electrode current collector, and then drying and cold pressing it. The negative electrode film layer includes silicon-based materials (specifically silicon oxide compounds), graphite, conductive carbon black, conductive carbon nanotubes, and binder polyacrylic acid in a weight ratio of 12.6:82.4:1.9:0.1:3.

[0557] The areal density of the negative electrode film is 9.0 mg / cm³. 2 The porosity is 22.1%, and the compacted density is 1.7 g / cm³. 3 .

[0558] 3. Isolation components

[0559] We provide PE (polyethylene) based films.

[0560] Preparation of the coating slurry: Inorganic alumina (Al2O3) particles, first organic particles (vinylidene fluoride-hexafluoropropylene copolymer with a number average molecular weight of 550,000), second organic particles (styrene-vinyl acetate-pyrrolidone copolymer with a number average molecular weight of 80,000), dispersant sodium carboxymethyl cellulose (CMC-Na), and wetting agent silicone-modified polyether are mixed evenly in an appropriate amount of deionized water at a dry weight ratio of 70:20:8:1:1 to obtain a coating slurry with a solid content of 38% (by weight). The inorganic alumina (Al2O3) particles have a volume average particle size (Dv50) of 1 μm, the first organic particles are secondary particles with a number average particle size of 15 μm, and the second organic particles are primary particles with a number average particle size of 2 μm.

[0561] The coating slurry is applied to the two surfaces of the PE base film, and the separator is obtained through processes such as drying and slitting.

[0562] 4. Preparation of electrolyte

[0563] The electrolyte consists of an organic solvent and a lithium salt. Ethyl carbonate (EC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC) are mixed in a volume ratio of 1:1:1 to obtain an organic solvent. Then, fully dried lithium salt LiPF6 is dissolved in the mixed organic solvent to prepare an electrolyte with a lithium salt concentration of 1 mol / L.

[0564] 5. Preparation of cylindrical battery cells

[0565] The positive electrode, separator, and negative electrode are stacked in sequence, with the separator positioned between the positive and negative electrodes to provide isolation. The positive electrode, separator, and negative electrode are then wound to form an electrode assembly. This assembly is placed in a cylindrical shell, dried, and then injected with electrolyte. After vacuum sealing, settling, formation, and shaping, a cylindrical battery cell is obtained. The electrode assembly and the shell are both cylindrical, comprising a housing and end caps. The housing includes integrally formed sidewalls and end walls, with the sidewalls surrounding the electrode assembly. The end caps and end walls are axially aligned with the housing. The cylindrical battery cell has a diameter of 46 mm and a height of 95 mm.

[0566] Performance testing

[0567] 1. Battery cell expansion volume test

[0568] A cylindrical cell with 0% charge is immersed in silicone oil, and its mass is measured as m0.

[0569] A cylindrical cell in a 100% charged state is immersed in silicone oil, and its mass is measured as m1.

[0570] The density of silicone oil is ρ 硅油 The volume change ΔV of a cylindrical battery cell at 100% state of charge and 0% state of charge is: ΔV=(m0-m1) / ρ 硅油 The reliability of a cylindrical battery cell is evaluated using ΔV. The smaller the ΔV, the smaller the volume expansion of the cylindrical battery cell and the higher the reliability. The larger the ΔV, the greater the volume expansion of the cylindrical battery cell and the worse the reliability.

[0571] Specifically, at 25°C, the cylindrical battery cell was discharged to 2.5V at 0.33C, and then discharged to 2.5V at 0.1C. At this point, the cylindrical battery cell was at 0% state of charge. At 25°C, the cylindrical battery cell was charged to 4.25V at 0.33C, and then charged to 4.25V at 0.1C. At this point, the cylindrical battery cell was at 100% state of charge.

[0572] 2. Energy density test of cylindrical battery cells

[0573] Under constant voltage (4.25V in Example 1), the first-cycle discharge capacity (Ah) multiplied by the ratio of discharge voltage to the mass of a cylindrical battery cell.

[0574] Energy density = First-cycle discharge capacity (Ah) × Discharge voltage (4.25V) / Mass of cylindrical battery cell (kg). The first-cycle discharge capacity is tested according to the following steps: At 45°C, the prepared cylindrical battery cell is fully charged at 1C and then fully discharged at 1C. This is one cycle of charge and discharge. The discharge capacity at this time is the first-cycle discharge capacity.

[0575] 3. Battery cycle performance test

[0576] At 45°C, the prepared cylindrical battery cells are fully charged at 1C and then fully discharged at 1C. This constitutes one charge-discharge cycle. The discharge capacity at this point is recorded as the first cycle discharge capacity. The cylindrical battery cells are then subjected to cyclic charge-discharge tests using the same method, and the discharge capacity after each cycle is recorded until the discharge capacity of the cylindrical battery cell decreases to 80% of its initial discharge capacity. The number of cycles at this point characterizes the cycle performance of the cylindrical battery cell. A higher number of cycles indicates better cycle performance.

[0577] Examples 2-5

[0578] Battery cells were prepared using a method similar to that of Example 1. The difference from Example 1 is that the preparation of the negative electrode in Examples 2-5 includes the following steps:

[0579] The negative electrode sheet includes a negative current collector and a negative electrode film layer. The negative electrode film layer is located on both sides of the negative current collector. The negative current collector is a copper foil. The negative electrode film layer is formed by uniformly coating the surface of the copper foil of the negative current collector with a negative electrode slurry (the solvent is deionized water), and then drying and cold pressing. The negative electrode film layer includes silicon-based materials (specifically silicon oxides), graphite, conductive carbon black, conductive carbon nanotubes, and binder polyacrylic acid; and the mass content and capacity areal density of silicon element are adjusted.

[0580] Examples 6-9

[0581] Battery cells were prepared using a method similar to that of Example 1. The difference from Example 1 is that the thickness of the sidewalls was adjusted in Examples 6-9.

[0582] The test results for each embodiment are shown in Table 1.

[0583] Table 1

[0584] Referring to Table 1, introducing silicon into the negative electrode active material can significantly improve the energy density of cylindrical battery cells. By incorporating organic particles into the separator, a gap can be formed between the positive and negative electrode plates, providing space for the expansion of the negative electrode plate. Referring to Table 1, the expansion volume of the cylindrical battery cell is less than or equal to 0.5 mL, and the cycle count of the cylindrical battery cell is greater than or equal to 800, indicating that the cylindrical battery cell exhibits good reliability and cycle performance.

[0585] Referring to Examples 1-5, by adjusting the mass content of silicon, the areal density can be adjusted simultaneously, which is beneficial for improving both the cycle performance and energy density of the battery cell. The gap provides space for the expansion of the negative electrode. When the silicon content reaches 19%, the expansion volume of the cylindrical battery cell is less than or equal to 0.5 mL, and the cycle count of the cylindrical battery cell is greater than or equal to 800.

[0586] Referring to Examples 1 and 6-9, by adjusting the sidewall thickness and coordinating it with the silicon content, it is beneficial to improve both the cycle performance and energy density of the battery cell while minimizing its volume expansion. The steel sidewall has high mechanical strength, effectively mitigating the volume expansion problem and simultaneously improving both the cycle performance and energy density of the battery cell.

[0587] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0588] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features. However, these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A cylindrical battery cell with a diameter ≥ 40 mm, comprising: shell; The electrode assembly is at least partially housed within the housing; The electrode assembly includes a positive electrode, a negative electrode, and a separator. The positive electrode, the negative electrode, and the separator are wound together. The separator separates the positive electrode and the negative electrode. The negative electrode active material of the negative electrode includes at least one of silicon-based material and carbon-based material. At least one of the positive electrode, the negative electrode, and the separator includes a base and a plurality of support portions. The base has two first surfaces disposed opposite to each other along its own thickness direction. The plurality of support portions protrude from at least one of the first surfaces to form a gap between the positive electrode and the negative electrode.

2. The cylindrical battery cell according to claim 1, wherein, The support portion is configured to be compressible.

3. The cylindrical battery cell according to claim 1 or 2, wherein, The plurality of support portions include a first support portion and a second support portion. On the same side of the base, the height of the first support portion protruding from the first surface is greater than the height of the second support portion protruding from the first surface.

4. The cylindrical battery cell according to claim 3, wherein, At least one of the positive electrode, the negative electrode, and the separator includes a plurality of organic particles, and the support portion includes the organic particles.

5. The cylindrical battery cell according to claim 4, wherein, The plurality of organic particles include a first organic particle and a second organic particle, wherein the number-average particle size of the first organic particle is greater than the number-average particle size of the second organic particle.

6. The cylindrical battery cell according to claim 4 or 5, wherein, The plurality of support portions include a first support portion and a second support portion. On the same side of the base, the height by which the first support portion protrudes from the first surface is greater than the height by which the second support portion protrudes from the first surface. The plurality of organic particles include a first organic particle and a second organic particle; the first support portion includes the first organic particle, and the second support portion includes the second organic particle.

7. The cylindrical battery cell according to any one of claims 4-6, wherein, The plurality of organic particles include a first organic particle, which comprises a homopolymer or copolymer of fluorinated alkenyl monomer units, a homopolymer or copolymer of olefin monomer units, a homopolymer or copolymer of unsaturated nitrile monomer units, a homopolymer or copolymer of epoxide monomer units, and one or more of the modified compounds of the above homopolymers or copolymers. Optionally, the first organic particles include polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinylidene fluoride, polyvinylidene fluoride, polyethylene, polypropylene, polyacrylonitrile, polyethylene oxide, copolymers of different fluorinated alkenyl monomer units, copolymers of fluorinated alkenyl monomer units and olefin monomer units, copolymers of fluorinated alkenyl monomer units and acrylic monomer units, copolymers of fluorinated alkenyl monomer units and acrylate monomer units, and one or more of the modified compounds of the above homopolymers or copolymers.

8. The cylindrical battery cell according to any one of claims 4-7, wherein, The plurality of organic particles include a second organic particle, which includes one or more of the following: a homopolymer or copolymer of acrylate monomer units, a homopolymer or copolymer of acrylate monomer units, a homopolymer or copolymer of styrene monomer units, a polyurethane compound, a rubber compound, and a modified compound of the above homopolymers or copolymers. Optionally, the second organic particle comprises one or more of the following: a copolymer of acrylate monomer units and styrene monomer units, a copolymer of acrylate monomer units and styrene monomer units, a copolymer of acrylate monomer units-acrylate monomer units-styrene monomer units, a copolymer of styrene monomer units and unsaturated nitrile monomer units, a copolymer of styrene monomer units-olefin monomer units-unsaturated nitrile monomer units, and modified compounds of the above copolymers.

9. The cylindrical battery cell according to any one of claims 1-8, wherein, The housing includes a sidewall surrounding the electrode assembly, the sidewall being made of steel and having a thickness of 0.3 mm to 1.5 mm, optionally 0.3 mm to 1.2 mm.

10. The cylindrical battery cell according to any one of claims 1-9, wherein, The negative electrode sheet includes a negative electrode current collector and a negative electrode film layer disposed on at least one side of the negative electrode current collector and containing the negative electrode active material, wherein the negative electrode active material includes a silicon-based material; The silicon content of the silicon-based material in the negative electrode film layer is 2% to 19% by mass, and can be selected as 6% to 13%.

11. The cylindrical battery cell according to any one of claims 1 to 10, wherein, The negative electrode has a capacity areal density greater than or equal to 3.2 mAh / cm³. 2 .

12. The cylindrical battery cell according to claim 11, wherein, The areal density of the negative electrode is 3.3 mAh / cm³. 2 Up to 11.5mAh / cm 2 .

13. The cylindrical battery cell according to claim 12, wherein, The areal density of the negative electrode is 3.96 mAh / cm³. 2 Up to 7.56mAh / cm 2 .

14. The cylindrical battery cell according to any one of claims 1-13, wherein, The gap is set to two, and the two gaps are respectively set on both sides of the positive electrode plate.

15. The cylindrical battery cell according to any one of claims 1-14, wherein, At least a portion of the gap has a radial dimension of 5 μm to 60 μm.

16. The cylindrical battery cell according to any one of claims 1-15, wherein, The gap extends along the winding direction of the electrode assembly, and the gap has a winding start end and a winding end.

17. The cylindrical battery cell according to claim 16, wherein, The radial dimension of the portion of the gap near the winding end is greater than the radial dimension of the portion of the gap near the winding start end.

18. The cylindrical battery cell according to claim 16 or 17, wherein, The gap is wound along the winding direction to form n winding loops, where n≥20 and n is a natural number; The innermost winding loop is the first winding loop; The radial dimension of the kth winding is less than the radial dimension of the (k+10)th winding, where k is a natural number and 5≤k≤n-15.

19. The cylindrical battery cell according to any one of claims 16-18, wherein, The gap is wound along the winding direction to form n winding loops, where n≥20 and n is a natural number; The innermost winding loop is the first winding loop; The average radial dimension of the (n-9) to (n-5)th windings is greater than the average radial dimension of the 5th to 9th windings.

20. The cylindrical battery cell according to any one of claims 1-19, wherein, The electrode assembly includes a central region and two end regions arranged along the axial direction of the cylindrical battery cell, with the central region located between the two end regions; The radial dimension of the portion of the gap located in the middle region is smaller than the radial dimension of the portion of the gap located in the end region.

21. The cylindrical battery cell according to claim 20, wherein, The radial dimension of the gap decreases in both directions from the two end regions toward the middle region.

22. The cylindrical battery cell according to any one of claims 1-21, wherein, The separator includes the base and a plurality of the support portions, the support portions including organic particles disposed on the base.

23. The cylindrical battery cell according to claim 22, wherein, The base of the separator includes a base film and an inorganic particle layer disposed on the base film, wherein the organic particles at least partially protrude from the inorganic particle layer.

24. The cylindrical battery cell according to any one of claims 1-23, wherein, The positive electrode sheet has a plurality of support portions on the side facing the separator, and the separator has a plurality of support portions on the side facing the positive electrode sheet. The plurality of support portions of the positive electrode sheet facing the separator are at least partially opposite to the plurality of support portions of the separator facing the positive electrode sheet; and / or, The negative electrode sheet has a plurality of support portions on the side facing the insulating member, and the insulating member has a plurality of support portions on the side facing the negative electrode sheet. The plurality of support portions of the negative electrode sheet facing the insulating member are at least partially opposite to the plurality of support portions of the insulating member facing the negative electrode sheet; and / or, The negative electrode sheet has a plurality of support portions on the side facing the positive electrode sheet, and the positive electrode sheet has a plurality of support portions on the side facing the negative electrode sheet. At least a portion of the plurality of support portions of the negative electrode sheet facing the positive electrode sheet are arranged opposite to the plurality of support portions of the positive electrode sheet facing the negative electrode sheet.

25. The cylindrical battery cell according to any one of claims 1-24, wherein, The isolation member has multiple support portions on both sides.

26. The cylindrical battery cell according to any one of claims 1-25, wherein, The gap includes a first gap and a second gap, the first gap being formed between the positive electrode and the separator, and the second gap being formed between the negative electrode and the separator.

27. The cylindrical battery cell according to any one of claims 1-26, wherein, The positive electrode sheet has a positive electrode recess on the side facing the separator.

28. The cylindrical battery cell according to claim 27, wherein, The positive electrode includes a positive electrode film layer, and the positive electrode recess is formed in the positive electrode film layer.

29. The cylindrical battery cell according to claim 28, wherein, The positive electrode recess extends through the positive electrode film layer along the axial direction of the cylindrical battery cell.

30. The cylindrical battery cell according to any one of claims 27-29, wherein, The positive electrode recess is multiple; at least a portion of the multiple positive electrode recesses is disposed on the inner side of the positive electrode sheet.

31. The cylindrical battery cell according to claims 27-30, wherein, The positive electrode sheet includes a plurality of positive electrode recesses spaced apart along the winding direction.

32. The cylindrical battery cell according to any one of claims 1-31, wherein, The negative electrode sheet has a negative electrode recess on the side facing the insulating element.

33. The cylindrical battery cell according to claim 32, wherein, The negative electrode sheet includes a negative electrode film layer, and the negative electrode recess is formed in the negative electrode film layer.

34. The cylindrical battery cell according to claim 33, wherein, The negative electrode recess extends through the negative electrode film layer along the axial direction of the cylindrical battery cell.

35. The cylindrical battery cell according to any one of claims 32-34, wherein, The negative electrode recess is multiple; at least a portion of the multiple negative electrode recesses is disposed on the inner side of the negative electrode sheet.

36. The cylindrical battery cell according to any one of claims 32-35, wherein, The negative electrode sheet includes a plurality of negative electrode recesses spaced apart along the winding direction.

37. The cylindrical battery cell according to any one of claims 1-36, wherein, One of the positive electrode and the negative electrode includes a first tab, and the other includes a second tab; The cylindrical battery cell includes a first electrode lead-out portion and a second electrode lead-out portion, wherein the first electrode lead-out portion is electrically connected to the first electrode tab, and the second electrode lead-out portion is electrically connected to the second electrode tab. Along the axial direction of the cylindrical battery cell, the first electrode lead and the second electrode lead are located on the same side of the electrode assembly.

38. The cylindrical battery cell according to any one of claims 1-37, wherein, The housing includes a shell and an end cap. The shell includes a side wall and an end wall. The side wall surrounds the electrode assembly. The end wall and the end cap are opposite each other along the axial direction of the cylindrical battery cell. The end cap is sealed to the side wall.

39. The cylindrical battery cell according to claim 38, wherein, One of the positive electrode and the negative electrode includes a first tab, and the other includes a second tab; The cylindrical battery cell also includes an electrode terminal insulated on the end wall, wherein one of the first tab and the second tab is electrically connected to the electrode terminal and the other is electrically connected to the end wall.

40. The cylindrical battery cell according to claim 39 further includes a first current collector, the first current collector being located on the side of the first tab facing the end wall and connected to the first tab; The electrode terminal abuts against and connects to the surface of the first current collector facing the end wall.

41. The cylindrical battery cell according to claim 40, wherein, The electrode terminal has a terminal recess on the side facing the first current collector, and / or the electrode terminal has a terminal recess on the side away from the first current collector; The bottom wall of the terminal recess is welded to the first current collector.

42. The cylindrical battery cell according to any one of claims 39-41, wherein, Both the first tab and the second tab are located at the end of the electrode assembly facing the end wall.

43. The cylindrical battery cell according to any one of claims 39-41, wherein, The first electrode tab is located at the end of the electrode assembly facing the end wall, and the second electrode tab is located at the end of the electrode assembly facing the end cap; The cylindrical battery cell further includes a second current collector connected to the second tab; the second current collector is connected to at least one of the end cap and the side wall.

44. The cylindrical battery cell according to any one of claims 1-43, wherein, The height of the outer casing is 1.3 to 4 times the diameter of the outer casing.

45. The cylindrical battery cell according to any one of claims 1-44, wherein, The height of the outer casing is 50mm to 150mm; and / or The diameter of the outer casing is 45mm to 80mm.

46. ​​A battery comprising a plurality of cylindrical battery cells according to any one of claims 1-45.

47. An electrical device comprising the battery of claim 46, the battery being used to provide electrical energy.

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