Cylindrical battery cell, battery, and electric device

Abstract

Embodiments of the present application provide a cylindrical battery cell, a battery, and an electric device. The cylindrical battery cell has a capacity greater than or equal to 20 Ah. The cylindrical battery cell comprises a casing and an electrode assembly accommodated in the casing. The electrode assembly comprises a first electrode sheet and a second electrode sheet having opposite polarities; the first electrode sheet and the second electrode sheet are wound in a winding direction; the first electrode sheet comprises a first current collector and a first film layer; the first current collector comprises a first coated region and a first tab; the surface of the first coated region is coated with the first film layer; the first tab extends from the first coated region toward one axial end of the cylindrical battery cell; and the surface of the first tab is not coated with the first film layer. The cylindrical battery cell comprises a first electrode lead-out portion, and the first tab is electrically connected to the first electrode lead-out portion. In the winding direction, the length of the connection area between the first tab and the first coated region is L1, the length of the first coating region is L0, and 0.8≤L1 / L0≤1.

Description

Cylindrical battery cell, battery and electric device

[0001] Cross-reference to Related Applications

[0002] This application claims priority to Chinese Patent Application No. 202410972029.X, filed on July 19, 2024, entitled “Cylindrical battery cell, battery and electric device”, the entire contents of which are incorporated herein by reference. TECHNICAL FIELD

[0003] The present application relates to the technical field of battery, and more particularly, to a cylindrical battery cell, a battery and an electric device. BACKGROUND

[0004] Battery cells, especially cylindrical battery cells, are widely used in electronic devices, such as mobile phones, notebook computers, electric cars, electric cars, electric planes, electric ships, electric toy cars, electric toy ships, electric toy planes, electric tools, and the like.

[0005] With the development of battery technology, users have higher requirements for the capacity of cylindrical battery cells. Due to the increase in capacity, the current of the cylindrical battery cell during charging also increases, which can cause an increase in heat generation of the cylindrical battery cell, affecting the cycle performance of the cylindrical battery cell. SUMMARY

[0006] The present application provides a cylindrical battery cell, a battery and an electric device, which can improve the cycle performance.

[0007] In a first aspect, the embodiments of the present application provide a cylindrical battery cell with a capacity greater than or equal to 20 Ah. The cylindrical battery cell includes a housing and an electrode assembly contained in the housing. The electrode assembly includes first and second polar plates with opposite polarities, the first and second polar plates being wound in a winding direction, the first polar plate including a first current collector and a first film layer, the first current collector including a first coated area and a first tab, the surface of the first coated area being coated with the first film layer, the first tab extending from the first coated area in an axial direction of the cylindrical battery cell, and the surface of the first tab being free of the first film layer. The cylindrical battery cell includes a first electrode lead-out portion, and the first tab is electrically connected to the first electrode lead-out portion. In the winding direction, the length of the connection position between the first tab and the first coated area is L1, the length of the first coated area is L0, and 0.8≤L1 / L0≤1.

[0008] L1 / L0 is greater than or equal to 0.8, the flow area of the connection position of the first coating area and the first tab can be increased, the impedance can be reduced, the heat generation of the connection position of the first coating area and the first tab can be reduced, the temperature rise of the first current collector and the first film layer can be reduced, the risk of ion precipitation can be reduced, the cycle performance of the cylindrical battery cell can be improved, the risk of thermal runaway can be reduced, and the reliability of the cylindrical battery cell can be improved. In the embodiment of the application, L1 / L0 is less than or equal to 1, the redundancy of the first tab can be reduced, the space can be saved, and the influence of lengthening the first tab on the energy density of the cylindrical battery cell can be reduced.

[0009] In some embodiments, 0.95≤L1 / L0≤1, the cycle performance and the energy density of the cylindrical battery cell can be considered to some extent.

[0010] In some embodiments, 3000mm≤L0≤9000mm; optionally, 4500mm≤L0≤7000mm.

[0011] L0 is positively correlated with the length of the first tab. In the embodiment of the application, L0 is greater than or equal to 3000mm, which can improve the capacity of the cylindrical battery cell; the first tab with a larger length is used, and the length of the first tab can be correspondingly increased, so that the flow capacity is improved, the impedance is reduced, the temperature rise of the first current collector and the first film layer is reduced, the risk of ion precipitation is reduced, and the cycle performance of the cylindrical battery cell is improved. When the diameter of the cylindrical battery cell is constant, the longer the first current collector is, the higher the weight proportion of the first current collector in the cylindrical battery cell is, and in the embodiment of the application, L0 is less than or equal to 9000mm, which can limit the space and weight occupied by the first current collector and reduce the loss of the energy density of the cylindrical battery cell.

[0012] In some embodiments, 2400mm≤L1≤9000mm; optionally, 3600mm≤L1≤7000mm.

[0013] In some embodiments, the thickness of the first tab is equal to the thickness of the first coating area. The first tab and the first coating area with the same thickness can simplify the forming process of the first tab.

[0014] In some embodiments, the sum of the thickness of the first film layer and the thickness of the first coating area is D1, the thickness of the first coating area is T1, and 0.17≤T1 / D1≤0.35.

[0015] In the embodiments of the present application, T1 / D1 is greater than or equal to 0.17, so as to increase the flow area of the first coating area, thereby reducing the heat generation of the first coating area during charging and discharging, reducing the temperature rise of the first film layer and the first coating area, improving the cycle performance of the cylindrical battery cell, and reducing the risk of thermal runaway. In the embodiments of the present application, T1 / D1 is less than or equal to 0.35, so as to limit the thickness ratio of the first coating area in the first pole piece, thereby reducing the loss of the capacity of the first pole piece. In the embodiments of the present application, T1 / D1 is limited to 0.17-0.35, so as to balance the cycle performance and the energy density of the cylindrical battery cell to a certain extent.

[0016] In some embodiments, 9μm≤T1≤17μm, and optionally, 11μm≤T1≤15μm. Limiting T1 to be greater than or equal to 9μm can make the first coating area have a larger flow area, thereby reducing the impedance, reducing the heat generation of the first coating area during charging and discharging, reducing the temperature rise of the first film layer and the first coating area, reducing ion precipitation (such as lithium precipitation), improving the cycle performance of the cylindrical battery cell, and reducing the risk of thermal runaway. Limiting T1 to be greater than or equal to 17μm can limit the thickness ratio of the first coating area in the first pole piece, thereby reducing the loss of the capacity of the first pole piece.

[0017] In some embodiments, the sum of the thickness of the first film layer and the thickness of the first coating area is D1, the thickness of the first film layer is T2, and 0.67≤T2 / D1≤0.81. Limiting T2 / D1 to be greater than or equal to 0.67 can increase the thickness ratio of the first film layer in the first pole piece, thereby increasing the capacity of the first pole piece and the energy density of the cylindrical battery cell. Limiting T2 / D1 to be less than or equal to 0.81 can limit the thickness ratio of the first film layer and the first coating area, so that the first coating area has a larger thickness, thereby reducing the impedance, reducing the heat generation of the first coating area during charging and discharging, reducing the temperature rise of the first film layer and the first coating area, reducing ion precipitation, improving the cycle performance of the cylindrical battery cell, and reducing the risk of thermal runaway. In the embodiments of the present application, T2 / D1 is limited to 0.67-0.81, so as to balance the cycle performance and the energy density of the cylindrical battery cell to a certain extent.

[0018] In some embodiments, the capacity of the cylindrical battery cell is 25Ah-50Ah. The cylindrical battery cell has a capacity greater than or equal to 25Ah, which is beneficial to improve the energy density when a plurality of cylindrical battery cells are assembled into a group. Limiting the capacity of the cylindrical battery cell to be less than or equal to 50Ah can limit the charging current of the cylindrical battery cell, thereby reducing the heat generation, reducing the temperature rise of the first film layer and the first current collector, and improving the cycle performance of the battery cell.

[0019] In some embodiments, the connection position of the first tab and the first coating region is continuously arranged along the winding direction, which can increase the flow area between the first tab and the first coating region, reduce the heat generation of the first coating region and the first tab, lower the temperature rise of the first film layer, and improve the cycle performance of the cylindrical battery cell.

[0020] In some embodiments, the first tab is continuously arranged as a whole along the winding direction, which can improve the current consistency and reduce the heat generation.

[0021] In some embodiments, the first tab includes a transition portion and a plurality of first sub-tabs arranged at intervals along the winding direction, the transition portion is connected to the first coating region, the first sub-tabs are connected to one end of the transition portion away from the first coating region, and the connection position of the transition portion and the first coating region is continuously arranged along the winding direction.

[0022] The plurality of first sub-tabs can bend inward in the radial direction of the cylindrical battery cell when pressed, so that the bent portions of some first sub-tabs are stacked in the axial direction and form a multi-layer structure. The multi-layer structure can improve the current carrying capacity, reduce the impedance, reduce the heat generation, and improve the cycle performance of the cylindrical battery cell. The plurality of first sub-tabs are not constrained to each other in the winding direction, which makes it easy to realize the directional bending of the first sub-tabs and helps to improve the morphology of the multi-layer structure.

[0023] In some embodiments, along the winding direction, the sum of the lengths of the connection positions of the plurality of first sub-tabs and the transition portion is L2, and the length of the connection position of the transition portion and the first coating region is L1. L2 and L1 satisfy: 0.6≤L2 / L1≤0.95. Limiting L2 / L1 to 0.6-0.95 can increase the flow area of the connection position of the first sub-tab and the transition portion, reduce the impedance, reduce the heat generation of the connection position of the first sub-tab and the transition portion, thereby reducing the temperature rise of the first current collector and the first film layer, reducing the risk of ion (e.g., lithium ion) precipitation, improving the cycle performance of the cylindrical battery cell, reducing the risk of thermal runaway, and improving the reliability of the cylindrical battery cell.

[0024] In some embodiments, an end of the first tab away from the first coating region is bent and forms a first stacking portion, the first stacking portion has a multi-layer structure in the axial direction of the cylindrical battery cell, and the first stacking portion is electrically connected to the first electrode lead portion. The multi-layer structure between the first stacking portion can transmit current, and electrically connecting the first stacking portion with the multi-layer structure to the first electrode lead portion can improve the current carrying capacity, reduce the impedance, reduce the heat generation, and improve the cycle performance of the cylindrical battery cell.

[0025] In some embodiments, the cylindrical battery cell comprises a first current collecting member located at least partially between the first laminated portion and the first electrode lead-out portion, and the first current collecting member is welded to the first laminated portion and the first electrode lead-out portion, respectively. Welding the first laminated portion with the multi-layer structure to the first current collecting member can not only reduce the risk of false welding, but also increase the welding area of the first tab and the first current collecting member, thereby improving the overcurrent capacity.

[0026] In some embodiments, the first electrode lead-out portion comprises an electrode terminal arranged in an insulating manner on the shell, at least a portion of the electrode terminal protrudes from the wall portion of the shell, and the first tab is electrically connected to the electrode terminal. By arranging at least a portion of the electrode terminal to protrude outward, the electrode terminal can be conveniently connected to the external busbar component, and the exposed area of the electrode terminal can be increased to improve the heat dissipation efficiency of the electrode terminal, thereby reducing the temperature rise of the first tab and improving the cycle performance of the cylindrical battery cell.

[0027] In some embodiments, the thermal conductivity of the electrode terminal is greater than that of the shell. The electrode terminal is electrically connected to the first tab, and the electrode terminal has better heat conduction capacity than the shell. Therefore, the electrode terminal can quickly conduct the heat of the first tab out, thereby slowing down the temperature rise of the first tab, reducing the thermal impact on the first film layer, and improving the cycle performance of the cylindrical battery cell.

[0028] In some embodiments, the first tab is a positive tab, and the first current collector is made of aluminum or aluminum alloy. Aluminum and aluminum alloy have good electrical conductivity and thermal conductivity. Using an aluminum first current collector can reduce impedance, reduce heat generation, and improve the cycle performance of the cylindrical battery cell.

[0029] In some embodiments, the second tab comprises a second current collector and a second film layer, the second current collector comprises a second coated area and a second tab, the surface of the second coated area is coated with the second film layer, the second tab extends from one end of the second coated area in the axial direction, and the surface of the second tab is not coated with the second film layer. In the axial direction, the first tab and the second tab are respectively located at two ends of the electrode assembly. The cylindrical battery cell comprises a second electrode lead-out portion, and the second tab is electrically connected to the second electrode lead-out portion. By arranging the first tab and the second tab at two ends of the electrode assembly, more space can be provided for the first tab and the second tab, so that the first tab and the second tab can have a larger length, the overcurrent capacity can be improved, the impedance can be reduced, and the cycle performance of the cylindrical battery cell can be improved.

[0030] In some embodiments, in the winding direction, the length of the second coated area is L3, and the length of the connection position of the second tab and the second coated area is L4. 0.8≤L4 / L3≤1; optionally, 0.95≤L4 / L3≤1.

[0031] In the embodiments of the present application, L4 / L3 is greater than or equal to 0.8, which can increase the flow area of the connection position of the second coating area and the second tab, reduce the impedance, reduce the heat generation of the connection position of the second coating area and the second tab, thereby reducing the temperature rise of the second current collector and the second film layer, reducing the risk of ion precipitation, improving the cycle performance of the cylindrical battery cell, reducing the risk of thermal runaway, and improving the reliability of the cylindrical battery cell. In the embodiments of the present application, L4 / L3 is less than or equal to 1, which can reduce the redundancy of the second tab, save space, and reduce the impact of lengthening the second tab on the energy density of the cylindrical battery cell.

[0032] In some embodiments, the first tab is a positive tab, and the second tab is a negative tab. The material of the first current collector is aluminum, and the material of the second current collector is copper.

[0033] In some embodiments, the thickness of the first coating area is greater than the thickness of the second coating area, and the thickness of the first tab is greater than the thickness of the second tab. Because the electrical conductivity of copper is higher than that of aluminum, setting the thickness of the aluminum first coating area to be greater than the thickness of the copper second coating area can reduce the difference in electrical conductivity between the first coating area and the second coating area, improve current consistency, reduce the temperature difference between the first coating area and the second coating area, and improve the cycle performance of the cylindrical battery cell. Similarly, setting the thickness of the aluminum first tab to be greater than the thickness of the copper second tab can reduce the difference in electrical conductivity between the first tab and the second tab, improve current consistency, reduce the temperature difference between the first tab and the second tab, and improve the cycle performance of the cylindrical battery cell.

[0034] In some embodiments, the electrode assembly further includes a separator, which is wound along the winding direction and separates the first tab and the second tab. The separator includes a base and a plurality of support portions, the base has two first surfaces oppositely arranged along the thickness direction of the base, and the plurality of support portions are protruded from at least one first surface to form a gap between the first tab and the second tab.

[0035] In the embodiments of the present application, the cylindrical battery cell has a higher capacity; as the capacity increases, the electrode assembly will generate a greater swelling force during charging. During the cycle process of the cylindrical battery cell, the gap can provide space for the expansion of the tab, reduce the pressure between the first tab and the second tab, thereby reducing the compression of the electrolyte in the internal pores of the first film layer and the internal pores of the second film layer, reducing the concentration difference of the electrolyte in each region of the tab, and improving the cycle performance of the cylindrical battery cell with a larger capacity. The gap can reduce the swelling amount of the electrode assembly, thereby reducing the compression of the shell, reducing the risk of deformation and cracking of the shell, and improving the reliability of the cylindrical battery cell. By setting the gap, the increase in the swelling force caused by increasing the capacity of the cylindrical battery cell can be reduced.

[0036] In some embodiments, the plurality of support portions includes a first support portion and a second support portion, the first support portion protruding from the first surface by a greater height than the second support portion. The first support portion has a greater height, which can support the first or second electrode tab to form a larger gap, thereby providing more space for the expansion of the electrode tab. The second support portion has a smaller height, which occupies less space. As the electrode tab expands, the gap gradually decreases; the second support portion can be compressed after the electrode tab expands to a certain extent, which can reduce the pressure on the electrode tab in the early stage of expansion. When the second support portion is compressed, the second support portion can slow down the expansion of the electrode tab to some extent, reduce the electrolyte squeezed out by the electrode tab, and improve the cycle performance of the cylindrical battery cell.

[0037] In some embodiments, the support portion includes organic particles disposed on the base portion. The organic particles can serve a supporting function to form the gap. When the cylindrical battery cell experiences thermal runaway, the organic particles can form a gel film structure at high temperatures, thereby reducing the diffusion channel of active ions and delaying the time of thermal spread, thereby improving the reliability of the cylindrical battery cell.

[0038] In some embodiments, the base portion includes a base film and an inorganic particle layer disposed on the base film, the organic particles at least partially protruding from the inorganic particle layer. The inorganic particle layer includes a plurality of inorganic particles, and gaps are formed between the inorganic particles and the organic particles, which are sufficient and unevenly distributed, thereby improving the air permeability of the separator and enabling the cylindrical battery cell to have better cycle performance and reliability.

[0039] In some embodiments, the plurality of organic particles includes first organic particles and second organic particles, the first organic particles having a number average particle size greater than the number average particle size of the second organic particles. The first organic particles with a larger number average particle size can support the first or second electrode tab to form a larger gap, thereby providing more space for the expansion of the electrode tab. The second organic particles with a smaller number average particle size can be compressed after the electrode tab expands to a certain extent, which can reduce the pressure on the electrode tab in the early stage of expansion. When the second organic particles are compressed, the second organic particles can slow down the expansion of the electrode tab to some extent, reduce the electrolyte squeezed out by the electrode tab, and improve the cycle performance of the cylindrical battery cell.

[0040] In some embodiments, the plurality of support portions includes a first support portion and a second support portion, the first support portion protruding from the first surface by a height greater than a height by which the second support portion protrudes from the first surface. The plurality of organic particles includes 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. By providing the first organic particles and the second organic particles with different number average particle sizes, the first support portion and the second support portion with different heights can be formed. The first support portion has a greater height, which can support the first or second electrode tab to form a larger gap, thereby providing more space for the expansion of the electrode tab. The second support portion can be compressed after the electrode tab expands to a certain extent, which can reduce the pressure on the electrode tab in the initial stage of expansion. When the second support portion is compressed, the second support portion can slow down the expansion of the electrode tab to some extent, reduce the electrolyte squeezed out by the electrode tab, and improve the cycle performance of the cylindrical battery cell.

[0041] In some embodiments, the radial dimension of at least part of the gap is 5-60 μm. The embodiments of the present application limit the radial dimension of the gap to be greater than or equal to 5 μm, which can provide space for the expansion of the electrode tab, reduce the expansion force, improve the cycle performance of the cylindrical battery cell, and reduce the risk of deformation and cracking of the shell. The embodiments of the present application limit the radial dimension of the gap to be less than or equal to 50 μm to shorten the ion migration path between the first electrode tab and the second electrode tab, reduce the internal resistance of the cylindrical battery cell, reduce heat generation, and reduce the impact of the gap on the energy density.

[0042] In some embodiments, the spacer is provided with a plurality of support portions on both sides. The gap includes a first gap formed between the first electrode tab and the spacer, and a second gap formed between the second electrode tab and the spacer. By providing a plurality of support portions on both sides of the spacer, the gap can be increased to provide more space for the expansion of the electrode tab.

[0043] In some embodiments, the gap extends in the winding direction, and the gap has a winding start end and a winding end. The radial dimension of the part of the gap near the winding start end is greater than or equal to the radial dimension of the part of the gap near the winding end. The part of the gap near the winding start end has a greater radial dimension to provide more expansion space for the electrode tab in the middle of the electrode assembly, reduce the risk of collapse of the middle of the electrode assembly due to expansion, and improve the cycle performance of the cylindrical battery cell.

[0044] In some embodiments, the radial dimension of at least part of the gap gradually decreases along the winding direction to provide more expansion space for the electrode tab in the middle of the electrode assembly, reduce the risk of collapse of the middle of the electrode assembly due to expansion, and improve the cycle performance of the cylindrical battery cell.

[0045] In some embodiments, the gap comprises a middle region and two end regions arranged along the axial direction, the middle region is located between the two end regions, and the radial dimension of the middle region is smaller than that of the end regions. The end regions have a larger radial dimension to facilitate the entry of electrolyte into the gap, improve the wettability of the electrolyte to the electrode sheet, and improve the cycle performance of the cylindrical battery cell.

[0046] In some embodiments, the radial dimension of the gap gradually decreases in the direction from the end region to the middle region, so as to reduce the abrupt change of the radial dimension of the gap, reduce the stress concentration of the second electrode sheet, and improve the cycle performance of the cylindrical battery cell.

[0047] In some embodiments, in the radial direction of the cylindrical battery cell, a part of the plurality of support portions is located between the first tab and the base. The first tab generates heat when current passes through, and the support portion can separate at least part of the first tab from the base, thereby reducing the heat conducted to the base, reducing the deformation of the base due to high temperature, reducing the risk of conduction between the first electrode sheet and the second electrode sheet, and improving the reliability of the cylindrical battery cell.

[0048] In some embodiments, the electrode assembly further comprises a separator, which is wound along the winding direction and separates the first electrode sheet and the second electrode sheet. The separator comprises a base and a plurality of support portions, the base has two first surfaces oppositely arranged along the thickness direction of the base, and the plurality of support portions protrude from at least one first surface to form a gap between the first electrode sheet and the second electrode sheet.

[0049] In the embodiments of the present application, the cylindrical battery cell has a higher capacity; as the capacity increases, the electrode assembly will generate greater swelling force when charging. During the cycle process of the cylindrical battery cell, the gap can provide space for the swelling of the electrode sheet, reduce the pressure between the first electrode sheet and the second electrode sheet, thereby reducing the extrusion of the electrolyte in the internal pores of the first membrane layer and the internal pores of the second membrane layer, reducing the concentration difference of the electrolyte in each region of the electrode sheet, and improving the cycle performance of the cylindrical battery cell with a larger capacity. The gap can reduce the swelling amount of the electrode assembly, thereby reducing the extrusion of the shell, reducing the risk of deformation and cracking of the shell, and improving the reliability of the cylindrical battery cell. By providing the gap, the increase in the swelling force caused by increasing the capacity of the cylindrical battery cell can be reduced.

[0050] In some embodiments, the plurality of support portions includes a first support portion and a second support portion, the first support portion protruding from the first surface by a greater height than the second support portion. The first support portion has a greater height, which can support the first or second electrode tab to form a larger gap, thereby providing more space for the expansion of the electrode tab. The second support portion has a smaller height, which occupies less space. As the electrode tab expands, the gap gradually decreases; the second support portion can be compressed after the electrode tab expands to a certain extent, which can reduce the pressure on the electrode tab in the initial stage of expansion. When the second support portion is compressed, the second support portion can slow down the expansion of the electrode tab to some extent, reduce the electrolyte squeezed out by the electrode tab, and improve the cycle performance of the cylindrical battery cell.

[0051] In some embodiments, the support portion includes organic particles disposed on the base portion. The organic particles can serve a supporting function to form the gap. When the cylindrical battery cell experiences thermal runaway, the organic particles can form a gel film structure at high temperatures, thereby reducing the diffusion channel of active ions and delaying the time of thermal spread, thereby improving the reliability of the cylindrical battery cell.

[0052] In some embodiments, the base portion includes a base film and an inorganic particle layer disposed on the base film, the organic particles at least partially protruding from the inorganic particle layer. The inorganic particle layer includes a plurality of inorganic particles, and gaps are formed between the inorganic particles and the organic particles, which are sufficient and unevenly distributed, thereby improving the air permeability of the separator and enabling the cylindrical battery cell to have better cycle performance and reliability.

[0053] In some embodiments, the plurality of organic particles includes first organic particles and second organic particles, the first organic particles having a number average particle size greater than the number average particle size of the second organic particles. The first organic particles with a larger number average particle size can support the first or second electrode tab to form a larger gap, thereby providing more space for the expansion of the electrode tab. The second organic particles with a smaller number average particle size can be compressed after the electrode tab expands to a certain extent, which can reduce the pressure on the electrode tab in the initial stage of expansion. When the second organic particles are compressed, the second organic particles can slow down the expansion of the electrode tab to some extent, reduce the electrolyte squeezed out by the electrode tab, and improve the cycle performance of the cylindrical battery cell.

[0054] In some embodiments, the plurality of support portions includes a first support portion and a second support portion, the first support portion protruding from the first surface by a height greater than a height by which the second support portion protrudes from the first surface. The plurality of organic particles includes 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. By providing the first organic particles and the second organic particles with different number average particle sizes, the first support portion and the second support portion with different heights can be formed. The first support portion has a greater height, which can support the first or second electrode tab to form a larger gap, thereby providing more space for the expansion of the electrode tab. The second support portion can be compressed after the electrode tab expands to a certain extent, which can reduce the pressure on the electrode tab in the initial stage of expansion. When the second support portion is compressed, the second support portion can slow down the expansion of the electrode tab to some extent, reduce the electrolyte squeezed out by the electrode tab, and improve the cycle performance of the cylindrical battery cell.

[0055] In some embodiments, the radial dimension of at least part of the gap is 5-60 μm. The embodiments of the present application limit the radial dimension of the gap to be greater than or equal to 5 μm, which can provide space for the expansion of the electrode tab, reduce the expansion force, improve the cycle performance of the cylindrical battery cell, and reduce the risk of deformation and cracking of the shell. The embodiments of the present application limit the radial dimension of the gap to be less than or equal to 50 μm to shorten the ion migration path between the first electrode tab and the second electrode tab, reduce the internal resistance of the cylindrical battery cell, reduce heat generation, and reduce the impact of the gap on the energy density.

[0056] In some embodiments, the spacer is provided with a plurality of support portions on both sides. The gap includes a first gap formed between the first electrode tab and the spacer, and a second gap formed between the second electrode tab and the spacer. By providing a plurality of support portions on both sides of the spacer, the gap can be increased to provide more space for the expansion of the electrode tab.

[0057] In some embodiments, the gap extends in the winding direction, and the gap has a winding start end and a winding end. The radial dimension of the part of the gap near the winding start end is greater than or equal to the radial dimension of the part of the gap near the winding end. The part of the gap near the winding start end has a greater radial dimension to provide more expansion space for the electrode tab in the middle of the electrode assembly, reduce the risk of the middle of the electrode assembly collapsing due to expansion, and improve the cycle performance of the cylindrical battery cell.

[0058] In some embodiments, the radial dimension of at least part of the gap gradually decreases in the winding direction to provide more expansion space for the electrode tab in the middle of the electrode assembly, reduce the risk of the middle of the electrode assembly collapsing due to expansion, and improve the cycle performance of the cylindrical battery cell.

[0059] In some embodiments, the gap comprises a middle region and two end regions arranged along the axial direction, the middle region is located between the two end regions, and a radial dimension of the middle region is smaller than that of the end regions. The end regions have a larger radial dimension to facilitate the entry of electrolyte into the gap, improve the wettability of the electrolyte to the electrode sheet, and improve the cycle performance of the cylindrical battery cell.

[0060] In some embodiments, the radial dimension of the gap gradually decreases in a direction from the end region to the middle region, so as to reduce the abrupt change of the radial dimension of the gap, reduce the stress concentration of the second electrode sheet, and improve the cycle performance of the cylindrical battery cell.

[0061] In some embodiments, in the radial direction of the cylindrical battery cell, a part of the plurality of support portions is located between the first tab and the base. The first tab generates heat when current passes through, and the support portion can separate at least part of the first tab from the base, thereby reducing the heat conducted to the base, reducing the deformation of the base due to high temperature, reducing the risk of conduction between the first electrode sheet and the second electrode sheet, and improving the reliability of the cylindrical battery cell.

[0062] In some embodiments, the melting point of the shell is greater than or equal to 1050℃. When the cylindrical battery cell is in thermal runaway, a large amount of heat and gas will be generated inside the electrode assembly, which can be discharged through the pressure relief mechanism of the cylindrical battery cell. The first tab has a relatively large length, which will slow down the discharge of heat and gas to some extent, so that the temperature inside the cylindrical battery cell is relatively high; the shell has a relatively high melting point, which can withstand a relatively high temperature, and the use of a shell with a high melting point can reduce the risk of the shell being melted through, realize directional pressure relief of the cylindrical battery cell, and reduce the risk of heat spreading.

[0063] In some embodiments, the tensile strength of the shell is greater than or equal to 300MPa. When the cylindrical battery cell is in thermal runaway, a large amount of heat and gas will be generated inside the electrode assembly, which can be discharged through the pressure relief mechanism of the cylindrical battery cell. The first tab has a relatively large length, which will slow down the discharge of heat and gas to some extent, so that the pressure inside the cylindrical battery cell is relatively high; the use of a shell with a relatively high tensile strength can reduce the risk of the shell being cracked, realize directional pressure relief of the cylindrical battery cell, and reduce the risk of heat spreading.

[0064] In some embodiments, the shell is a steel shell. The steel shell has a relatively high melting point and strength, which is not easy to break when the cylindrical battery cell is in thermal runaway, thereby improving the reliability of the cylindrical battery cell. During the cycle of the cylindrical battery cell, the electrode assembly will swell; the steel shell has a relatively high strength and deforms less under the swelling force of the electrode assembly, so the steel shell can effectively limit the deformation of the electrode assembly.

[0065] In some embodiments, the shell comprises a housing and an end cover, the housing comprises an integrally formed side wall and an end wall, the side wall surrounds the electrode assembly, the end wall and the end cover are opposite along the axial direction of the cylindrical battery cell, and the end cover is sealingly connected to the side wall.

[0066] In some embodiments, the second tab comprises a second lug. The first electrode lead-out part comprises an electrode terminal insulatively provided on the end wall, the first lug is electrically connected to the electrode terminal, and the second lug is electrically connected to the end wall. The electrode terminal and the end wall can serve as two exposed electrodes of the cylindrical battery cell, and the electrode terminal and the end wall are located on the same side, which facilitates the assembly of a plurality of cylindrical battery cells into a group and simplifies the battery structure.

[0067] In some embodiments, the cylindrical battery cell further comprises a first current collecting member located on a side of the first tab facing the end wall and connected to the first tab. The electrode terminal abuts against and is connected to a surface of the first current collecting member facing the end wall.

[0068] In some embodiments, the electrode terminal is provided with a terminal recess on a side facing the first current collecting member and / or a terminal recess on a side facing away from the first current collecting member. The bottom wall of the terminal recess is welded to the first current collecting member. By providing the terminal recess, the thickness of the bottom wall of the terminal recess can be reduced, the power required for welding the electrode terminal and the first current collecting member from the outside can be reduced, the risk of particles generated by welding falling into the shell can be reduced, and the reliability of the cylindrical battery cell can be improved.

[0069] In some embodiments, the first tab is located at one end of the first tab facing the end wall, and the second lug is located at one end of the second tab facing the end cover. The cylindrical battery cell further comprises a second current collecting member connected to the second lug; and the second current collecting member is connected to at least one of the end cover and the side wall.

[0070] In some embodiments, the side wall is provided with a protrusion protruding inwardly, and at least part of the protrusion is located between the end cover and the second lug in the axial direction. The second current collecting member is connected to the protrusion. The protrusion overlaps the second lug in the axial direction, which can limit the movement of the second lug in the axial direction when the cylindrical battery cell is subjected to external impact, and reduce the risk of failure of the connection between the second lug and the second current collecting member. Connecting the second current collecting member to the protrusion can shorten the conductive path between the second lug and the end wall, reduce the resistance, reduce the heat generation, and improve the cycle performance of the cylindrical battery cell.

[0071] In some embodiments, a part of the second current collecting member is located on a side of the protrusion facing the end cover and connected to the protrusion. The second current collecting member can be connected to the protrusion from the outside of the protrusion, which can reduce the assembly difficulty.

[0072] In some embodiments, the height of the shell is 1.3 to 4 times the diameter of the shell. When the shell satisfies the above size requirements, the structural stability of the shell is relatively high, and the use reliability of the cylindrical battery cell can be improved.

[0073] In some embodiments, the height of the shell is 50 mm to 150 mm.

[0074] In some embodiments, the diameter of the shell is 45 mm to 80 mm.

[0075] In some embodiments, the diameter of the shell is 45 mm to 80 mm.

[0076] In some embodiments, the diameter of the shell is 45 mm to 80 mm. BRIEF DESCRIPTION OF DRAWINGS

[0077] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments of the present application. Obviously, the drawings described below are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor on the basis of the drawings.

[0078] FIG. 1 is a structural schematic diagram of a vehicle according to some embodiments of the present application;

[0079] FIG. 2 is an exploded schematic diagram of a battery according to some embodiments of the present application;

[0080] FIG. 3 is a structural schematic diagram of a battery module shown in FIG. 2;

[0081] FIG. 4 is a structural schematic diagram of a cylindrical battery cell according to some embodiments of the present application;

[0082] FIG. 5 is an exploded schematic diagram of the cylindrical battery cell shown in FIG. 4;

[0083] FIG. 6 is a structural schematic diagram of an electrode assembly of the cylindrical battery cell according to some embodiments of the present application;

[0084] FIG. 7 is a sectional view of the electrode assembly shown in FIG. 6 along the A-A direction;

[0085] FIG. 8 is a partial structural schematic diagram of the electrode assembly of the cylindrical battery cell according to some embodiments of the present application;

[0086] FIG. 9 is a schematic diagram of a first electrode sheet of the cylindrical battery cell according to some embodiments of the present application in a flattened state;

[0087] FIG. 10 is a sectional view of the first electrode sheet shown in FIG. 9;

[0088] FIG. 11 is a schematic view of a second electrode tab of a cylindrical battery cell in a flattened state, according to some embodiments of the present application;

[0089] FIG. 12 is a cross-sectional view of the second electrode tab shown in FIG. 11;

[0090] FIG. 13 is a schematic view of a first electrode tab of a cylindrical battery cell in a flattened state, according to some embodiments of the present application;

[0091] FIG. 14 is a schematic view of a first electrode tab of a cylindrical battery cell in a flattened state, according to some embodiments of the present application;

[0092] FIG. 15 is a schematic view of a first electrode tab of a cylindrical battery cell in a flattened state, according to some embodiments of the present application;

[0093] FIG. 16 is a schematic view of a first electrode tab of a cylindrical battery cell in a flattened state, according to some embodiments of the present application;

[0094] FIG. 17 is a cross-sectional view of an electrode assembly of a cylindrical battery cell, according to some embodiments of the present application;

[0095] FIG. 18 is an enlarged view of the dashed box in FIG. 17;

[0096] FIG. 19 is a schematic view of a separator of an electrode assembly of a cylindrical battery cell, according to some embodiments of the present application;

[0097] FIG. 20 is a partial cross-sectional view of an electrode assembly of a cylindrical battery cell, according to some embodiments of the present application;

[0098] FIG. 21 is a schematic view of a separator of an electrode assembly of a cylindrical battery cell, according to some embodiments of the present application;

[0099] FIG. 22 is a partial cross-sectional view of an electrode assembly of a cylindrical battery cell, according to some embodiments of the present application;

[0100] FIG. 23 is a partial cross-sectional view of an electrode assembly of a cylindrical battery cell, according to some embodiments of the present application;

[0101] FIG. 24 is a cross-sectional view of a cylindrical battery cell, according to some embodiments of the present application;

[0102] FIG. 25 is an enlarged view of the circle in FIG. 24;

[0103] FIG. 26 is a partial cross-sectional view of a cylindrical battery cell, according to some embodiments of the present application.

[0104] In the drawings, the drawings are not drawn to scale.

[0105] The reference signs are explained as follows: 1, vehicle; 2, battery; 3, controller; 4, motor; 5, case; 5a, first case portion; 5b, second case portion; 5c, accommodation space; 6, battery module; 7, cylindrical battery cell; 7a, first electrode lead-out portion; 7b, second electrode lead-out portion; 10, electrode assembly; 11, first tab; 111, first current collector; 1111, first coating region; 1112, first tab; 1112a, first lamination portion; 1112b, transition portion; 1112c, connection portion; 1112d, first sub-tab; 1112e, tab section; 112, first film layer; 12, second tab; 121, second current collector; 1211, second coating region; 1212, second tab; 122, second film layer; 13, separator; 131, base portion; 1311, base film; 1312, inorganic particle layer; 131a, first surface; 132, support portion; 132a, first support portion; 132b, second support portion; 20, housing; 21, case; 211, end wall; 212, side wall; 2121, protrusion; 2122, crimp portion; 2123, recess; 22, end cap; 30, electrode terminal; 31, terminal recess; 32, through-hole; 40, first current collecting member; 50, cover plate; 60, second current collecting member; 70, insulating member; C1, middle region; C2, end region; C3, transition region; P, organic particle; P1, first organic particle; P2, second organic particle; E1, winding start end; E2, winding end end; E3, first winding start end; E4, first winding end end; E5, second winding start end; E6, second winding end end; E7, first end; E8, second end; G, gap; G1, first gap; G2, second gap; J, notch; V, winding direction; Z, axial direction. DETAILED DESCRIPTION

[0106] In order to make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0107] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used in the specification herein is for describing particular embodiments only and is not intended to be limiting of the application. Unless otherwise defined, all terms used in disclosing the application, including technical and scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description of the application herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The articles "a", "an", and "the" as used herein are to be construed to mean "at least one" or "one or more", unless otherwise indicated. The terms "comprise", "comprising", "comprises", "include", "including", and "includes" as used herein are to be construed as optionally permitting the presence of one or more elements, so long as the presence of the one or more elements does not change the basic function of the device or method to which the term refers. The terms "first", "second", "third", etc. as used herein are to be construed as describing different objects, and not to be construed as describing a particular order or sequence unless otherwise indicated.

[0108] Reference throughout this application to "example" means that a particular feature, structure, or characteristic described in connection with the example can be included in at least one embodiment of the application. The appearances of the phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are they necessarily mutually exclusive of one another.

[0109] In the description of the application, it is necessary to explain that, unless otherwise explicitly defined and limited, the terms "mount", "connect", "connection", "attach" should be understood in a broad sense, for example, it can be fixed connection, or detachable connection, or integrally connected; it can be directly connected, or indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0110] In this application, the term "and / or", only describes the relationship between the associated objects, which means that there can be three kinds of relationships, for example, A and / or B, which can mean that A exists alone, A and B exist together, and B exists alone. In addition, the character " / " in this application generally represents that the front and rear associated objects have an "or" relationship.

[0111] In the embodiments of the application, the same reference signs represent the same parts, and for the sake of brevity, the detailed description of the same parts is omitted in different embodiments. It should be understood that the thickness, length and width of various components in the embodiments of the application shown in the drawings, as well as the overall thickness, length and width of the integrated device, are only exemplary and should not constitute any limitation on the application.

[0112] "Multiple" appearing in this application refers to two or more (including two).

[0113] The cylindrical battery cell can be a cylindrical secondary battery, which refers to a battery cell that can be activated by charging after discharging.

[0114] The battery can refer to a single physical module including one or more cylindrical battery monomers to provide higher voltage and capacity.

[0115] The cylindrical battery monomer generally includes an electrode assembly and a housing for accommodating the electrode assembly. The electrode assembly generally includes a positive electrode sheet, a negative electrode sheet, and a separator separating the positive electrode sheet and the negative electrode sheet.

[0116] During the charging and discharging process of the cylindrical battery monomer, the positive electrode sheet and the negative electrode sheet generate heat under the action of the current, thereby causing the temperature of the cylindrical battery monomer to rise. In particular, as the capacity of the cylindrical battery monomer increases, and the user's requirement for the charging speed gradually increases, the current of the cylindrical battery monomer during charging is also increasing. As the current increases, the heat generation of the positive electrode sheet and the negative electrode sheet also increases, which causes the local temperature of the cylindrical battery monomer to rise greatly, resulting in the cycle attenuation of the cylindrical battery monomer due to temperature rise, affecting the cycle performance and reliability performance of the cylindrical battery monomer.

[0117] In view of this, the embodiments of the present application provide a technical scheme, which increases the length of the coating area of the electrode sheet and the connection position of the tab to improve the overcurrent capacity of the electrode sheet, reduce the heat generation of the electrode sheet, reduce the temperature rise of the cylindrical battery monomer, and improve the cycle performance and reliability performance of the cylindrical battery monomer.

[0118] The cylindrical battery monomer described in the embodiments of the present application is suitable for a battery and a power consumption device using the battery.

[0119] The power consumption device can be a device using a battery as a power source or a variety of energy storage systems using a battery as an energy storage element. The power consumption device can be, but is not limited to, a mobile phone, a tablet, a notebook computer, an electric toy, an electric tool, an electric vehicle, an electric car, a ship, a spacecraft, etc. Among them, the electric toy can include a fixed or mobile electric toy, such as a game console, an electric car toy, an electric ship toy, and an electric plane toy, etc. The spacecraft can include an airplane, a rocket, a space shuttle, a spacecraft, etc.

[0120] The following embodiments take the vehicle as an example for convenience of description.

[0121] FIG. 1 is a structural schematic diagram of a vehicle provided by some embodiments of the present application.

[0122] As shown in FIG. 1, the vehicle 1 is internally provided with a battery 2, which can be arranged at the bottom, head or tail of the vehicle 1. The battery 2 can be used for power supply of the vehicle 1, for example, the battery 2 can be used as an operating power source of the vehicle 1.

[0123] The vehicle 1 can further include a controller 3 and a motor 4, the controller 3 being used to control the battery 2 to supply power to the motor 4, for example, for the working power demand of the vehicle 1 during starting, navigation and driving.

[0124] In some embodiments of the present application, the battery 2 can not only serve as the power source for operating the vehicle 1, but also serve as the driving power source for the vehicle 1, replacing or partially replacing the fuel or natural gas to provide driving power for the vehicle 1.

[0125] FIG. 2 is an exploded schematic view of the battery according to some embodiments of the present application. As shown in FIG. 2, the battery 2 includes a box body 5 and a cylindrical battery cell (not shown in FIG. 2), and the cylindrical battery cell is accommodated in the box body 5.

[0126] The box body 5 is used to accommodate the cylindrical battery cell, and the box body 5 can have various structures. In some embodiments, the box body 5 can include a first box body part 5a and a second box body part 5b, the first box body part 5a and the second box body part 5b are mutually covered, and the first box body part 5a and the second box body part 5b jointly define an accommodation space 5c for accommodating the cylindrical battery cell. The second box body part 5b can be a hollow structure with one end open, and the first box body part 5a is a plate-like structure, which is covered on the open side of the second box body part 5b to form the box body 5 with the accommodation space 5c; or the first box body part 5a and the second box body part 5b can both be hollow structures with one side open, and the open side of the first box body part 5a is covered on the open side of the second box body part 5b to form the box body 5 with the accommodation space 5c. Of course, the first box body part 5a and the second box body part 5b can have various shapes, such as a cylinder, a cuboid, etc.

[0127] In order to improve the sealing performance of the first box body part 5a and the second box body part 5b after being connected, a sealing member such as sealing glue, a sealing ring, etc. can be arranged between the first box body part 5a and the second box body part 5b.

[0128] Suppose the first box body part 5a is covered on the top of the second box body part 5b, the first box body part 5a can also be referred to as an upper box cover, and the second box body part 5b can also be referred to as a lower box body.

[0129] In the battery 2, the cylindrical battery cell can be one or multiple. If the cylindrical battery cell is multiple, the multiple cylindrical battery cells can be connected in series, in parallel or in a mixed manner, and the mixed manner means that there are both series connection and parallel connection among the multiple cylindrical battery cells. The multiple cylindrical battery cells can be directly connected in series, in parallel or in a mixed manner, and then the whole of the multiple cylindrical battery cells is accommodated in the box body 5; of course, the multiple cylindrical battery cells can first be connected in series, in parallel or in a mixed manner to form a battery module 6, and then the multiple battery modules 6 are connected in series, in parallel or in a mixed manner to form a whole, which is accommodated in the box body 5.

[0130] The cylindrical battery cell can be the smallest unit constituting the battery.

[0131] In some embodiments, the box 5 can be part of the chassis structure of the vehicle. For example, part of the box 5 can be part of the floor of the vehicle, or part of the box 5 can be part of the cross beam and longitudinal beam of the vehicle.

[0132] In some embodiments, the battery 2 can be an energy storage device. The energy storage device includes an energy storage container, an energy storage cabinet, etc.

[0133] FIG. 3 is a structural schematic diagram of the battery module shown in FIG. 2.

[0134] In some embodiments, as shown in FIG. 3, the plurality of cylindrical battery cells 7 are connected in series or in parallel or in a hybrid manner to form a battery module 6. The plurality of battery modules 6 are connected in series or in parallel or in a hybrid manner to form a whole and are accommodated in the box.

[0135] The plurality of cylindrical battery cells 7 in the battery module 6 can be electrically connected through a busbar component to realize parallel connection, series connection or hybrid connection of the plurality of cylindrical battery cells 7 in the battery module 6. The busbar component can be one or more, and each busbar component is used to electrically connect at least two cylindrical battery cells 7.

[0136] The cylindrical battery cell 7 can be a lithium ion battery cell, a sodium ion battery cell, a sodium lithium ion battery cell, a lithium metal battery cell, a sodium metal battery cell, a lithium sulfur battery cell, a magnesium ion battery cell, a nickel hydrogen battery cell, a nickel cadmium battery cell, a lead-acid battery cell, etc.

[0137] Referring to FIGS. 4-12, the present application provides a cylindrical battery cell 7, which includes a housing 20 and an electrode assembly 10, and the electrode assembly 10 is accommodated in the housing 20.

[0138] The housing 20 is a hollow structure, and an accommodation space for accommodating the electrode assembly 10 and the electrolyte is formed inside. The housing 20 of the cylindrical battery cell 7 can be a cylindrical housing.

[0139] As an example, the housing 20 includes a shell 21 having an opening and an end cap 22 for covering the opening.

[0140] The shell 21 is a component for cooperating with the end cap 22 to form an internal cavity of the cylindrical battery cell 7, and the internal cavity formed can be used to accommodate the electrode assembly 10, the electrolyte and other components.

[0141] The shell 21 and the end cap 22 can be independent components. As an example, an opening can be provided on the shell 21, and the end cap 22 is used to cover the opening to form the internal cavity of the cylindrical battery cell 7.

[0142] The shell 21 can be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, etc.

[0143] The shape of the end cover 22 can be adapted to the shape of the shell 21 to fit the shell 21. The material of the end cover 22 can be the same as or different from the material of the shell 21. Optionally, the end cover 22 can be made of a material with certain hardness and strength (such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc.), so that the end cover 22 is not easy to deform when subjected to extrusion and collision, so that the cylindrical battery cell 7 can have higher structural strength and reliable performance can also be improved.

[0144] The end cover 22 is connected to the shell 21 by welding, bonding, clamping or other means.

[0145] The shell 21 can be open at one end or both ends. In some examples, the shell 21 can be a one-side open structure, and the end cover 22 is provided as one and covers the shell 21. In other examples, the shell 21 can also be a two-side open structure, and the end cover 22 is provided as two, and the two end covers 22 cover the two openings of the shell 21 respectively.

[0146] In some embodiments, the shell 21 includes an integrally formed side wall 212 and an end wall 211, the end wall 211 and the end cover 22 are opposite along the axial direction Z of the cylindrical battery cell 7, and the end cover 22 is sealingly connected to the side wall 212.

[0147] In some embodiments, the electrode assembly 10 is a component that undergoes an electrochemical reaction in the cylindrical battery cell 7.

[0148] In some embodiments, the electrode assembly 10 includes first and second polar plates 11 and 12 with opposite polarities. One of the first and second polar plates 11 and 12 is a positive polar plate, and the other is a negative polar plate.

[0149] In some embodiments, the first polar plate 11 includes a first current collector 111 and a first film layer 112, and the first film layer 112 is disposed on at least one surface of the first current collector 111. The second polar plate 12 includes a second current collector 121 and a second film layer 122, and the second film layer 122 is disposed on at least one surface of the first current collector 111.

[0150] As an example, the first current collector 111 has two opposite surfaces in the thickness direction thereof, and the first film layer 112 is disposed on any one or both of the two opposite surfaces of the first current collector 111. The second current collector 121 has two opposite surfaces in the thickness direction thereof, and the second film layer 122 is disposed on any one or both of the two opposite surfaces of the second current collector 121.

[0151] In some examples, the first tab 11 is a positive tab, and the second tab 12 is a negative tab. Correspondingly, the first current collector 111 is a positive current collector, and the second current collector 121 is a negative current collector. The first film layer 112 is a positive film layer, and the second film layer 122 is a negative film layer. In other examples, the first tab 11 is a negative tab, and the second tab 12 is a positive tab. Correspondingly, the first current collector 111 is a negative current collector, and the second current collector 121 is a positive current collector. The first film layer 112 is a negative film layer, and the second film layer 122 is a positive film layer.

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

[0153] As an example, the positive film layer includes a positive active material, which can include at least one of the following materials: lithium-containing phosphates, lithium transition metal oxides, and respective modified compounds thereof. However, the present application is not limited to these materials, and other conventional materials that can be used as battery positive active materials can also be used. These positive active materials can be used alone or in combination with two or more. Among them, examples of lithium-containing phosphates can include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (which can also be referred to as LFP)), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO4), a composite material of lithium manganese phosphate and carbon, lithium manganese iron phosphate, and a composite material of lithium manganese iron phosphate and carbon. Examples of lithium transition metal oxides can include, but are not limited to, at least one of 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, lithium nickel cobalt manganese oxide (such as LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (which can also be referred to as NCM 333 ), LiNi 0.5 Co 0.2 Mn 0.3 O2 (which can also be referred to as NCM 523 ), LiNi 0.5 Co 0.25 Mn 0.25 O2 (which can also be referred to as NCM 211 ), LiNi 0.6 Co0.2 Mn 0.2 O2(also referred to as NCM 622 ), LiNi 0.8 Co 0.1 Mn 0.1 O2(also referred to as NCM 811 ), lithium nickel cobalt aluminum oxide (e.g., LiNi 0.80 Co 0.15 Al 0.05 O2), and modified compounds thereof.

[0154] As an example, the negative current collector can employ a metal foil, a foam metal, a foam carbon, or a composite current collector. For example, as the metal foil, silver surface-treated aluminum or stainless steel, stainless steel, copper, aluminum, nickel, a carbon electrode, a carbon, nickel, or titanium, or the like can be employed. The foam metal can be a foam nickel, a foam copper, a foam aluminum, a foam alloy, or the like. The composite current collector can include a polymer material base layer and a metal layer. The composite current collector can be formed by forming a metal material (copper, a copper alloy, nickel, a nickel alloy, titanium, a titanium alloy, silver, and a silver alloy, or the like) on a polymer material base material (e.g., a base material of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, or the like).

[0155] As an example, the negative electrode film layer includes a negative electrode active material. For example, the negative electrode active material can include at least one of artificial graphite, natural graphite, soft carbon, hard carbon, a silicon-based material, a tin-based material, lithium titanate, or the like. The silicon-based material can be selected from at least one of elemental silicon, a silicon oxide compound, a silicon-carbon composite, a silicon-nitrogen composite, and a silicon alloy. The tin-based material can be selected from at least one of elemental tin, a tin oxide compound, and a tin alloy. However, the present application is not limited to these materials, and other conventional materials that can be used as a battery negative electrode active material can also be used. These negative electrode active materials can be used alone or in combination with two or more.

[0156] In some embodiments, the material of the positive current collector can be aluminum, and the material of the negative current collector can be copper.

[0157] In some embodiments, the electrode assembly 10 further includes a separator 13 disposed between the positive electrode sheet and the negative electrode sheet. The separator 13 can function to prevent short circuiting of the positive and negative electrodes, while allowing the passage of active ions.

[0158] In some embodiments, the cylindrical battery cell 7 further includes an electrolyte that functions to conduct ions between the positive electrode sheet and the negative electrode sheet. The electrolyte can be in a liquid state, a gel state, or a solid state.

[0159] In some embodiments, the liquid electrolyte includes an electrolyte salt and a solvent.

[0160] As an example, the electrolyte salt can be selected from at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bisfluorosulfonimide, lithium bis-trifluoromethanesulfonimide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluoro oxalato borate, lithium di-oxalato borate, lithium difluoro di-oxalato phosphate, and lithium tetrafluoro oxalato phosphate.

[0161] As an example, the solvent can be selected from at least one of ethylene carbonate, propylene carbonate, methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, butyrosulfone, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone. The solvent can also be selected from an ether solvent. The ether solvent can include one or more of ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyl tetrahydrofuran, diphenyl ether, and a crown ether.

[0162] In some embodiments, the gel-state electrolyte includes a polymer as a backbone network of the electrolyte, in combination with an ionic liquid-lithium salt.

[0163] In some embodiments, the solid-state electrolyte includes a polymer solid-state electrolyte, an inorganic solid-state electrolyte, a composite solid-state electrolyte.

[0164] As an example, the polymer solid-state electrolyte can be a polyether (polyethylene oxide), a polysiloxane, a polycarbonate, a polyacrylonitrile, a polyvinylidene fluoride, a polymethyl methacrylate, a single-ion polymer, a polyionic liquid-lithium salt, a cellulose, or the like.

[0165] As an example, the inorganic solid-state electrolyte can be one or more of an oxide solid electrolyte (crystalline perovskite, sodium superionic conductor, garnet, amorphous LiPON thin film), a sulfide solid electrolyte (crystalline lithium superionic conductor (lithium germanium phosphorous sulfide, argyrodite), amorphous sulfide), and a halide solid electrolyte, a nitride solid electrolyte, and a hydride solid electrolyte.

[0166] As an example, the composite solid-state electrolyte is formed by adding an inorganic solid-state electrolyte filler to a polymer solid-state electrolyte.

[0167] In some embodiments, the first electrode tab 11, the second electrode tab 12, and the separator 13 are wound. The electrode assembly 10 is a wound structure. As an example, the first electrode tab 11, the separator 13, and the second electrode tab 12 are wound in a cylindrical wound structure.

[0168] In some embodiments, the cylindrical battery cell 7 further comprises a first electrode lead-out portion 7a and a second electrode lead-out portion 7b, the first electrode lead-out portion 7a being electrically connected to the first tab 11, and the second electrode lead-out portion 7b being electrically connected to the second tab 12. The first electrode lead-out portion 7a and the second electrode lead-out portion 7b are insulated from each other.

[0169] The first electrode lead-out portion 7a and the second electrode lead-out portion 7b are used to connect with external circuits to achieve charging or discharging of the cylindrical battery cell 7. Exemplarily, when a plurality of cylindrical battery cells 7 are assembled into a group, the first electrode lead-out portion 7a and the second electrode lead-out portion 7b are used to connect with busbar components.

[0170] The first electrode lead-out portion 7a can comprise an electrode terminal 30 provided on the outer shell 20. The electrode terminal 30 is separately formed from the outer shell 20 and assembled together during the production of the cylindrical battery cell 7. Exemplarily, the electrode terminal 30 is insulatively provided on the end cap 22 or the casing 21.

[0171] Alternatively, the first electrode lead-out portion 7a can also be a part of the outer shell 20. For example, the first electrode lead-out portion 7a can be the end cap 22 of the outer shell 20, or the first electrode lead-out portion 7a can be the end wall 211 of the casing 21 opposite to the end cap 22.

[0172] The second electrode lead-out portion 7b can be an electrode terminal 30 provided on the outer shell 20. Alternatively, the second electrode lead-out portion 7b can be a part of the outer shell 20. For example, the second electrode lead-out portion 7b can be the end cap 22 of the outer shell 20, or the second electrode lead-out portion 7b can be the end wall 211 of the casing 21 opposite to the end cap 22.

[0173] In some embodiments, the first electrode lead-out portion 7a is an electrode terminal 30, and the second electrode lead-out portion 7b is an end wall 211 of the casing 21, the electrode terminal 30 being insulatively provided on the end wall 211. In other embodiments, the second electrode lead-out portion 7b is an electrode terminal 30, and the first electrode lead-out portion 7a is an end wall 211 of the casing 21, the electrode terminal 30 being insulatively provided on the end wall 211.

[0174] In some embodiments, the cylindrical battery cell 7 has a capacity greater than or equal to 20 Ah. The cylindrical battery cell 7 includes a housing 20 and an electrode assembly 10 housed in the housing 20. The electrode assembly 10 includes first and second polar plates 11 and 12 that are opposite in polarity. The first and second polar plates 11 and 12 are wound in a winding direction V. The first polar plate 11 includes a first current collector 111 and a first film layer 112, the first current collector 111 includes a first coated area 1111 and a first tab 1112, a surface of the first coated area 1111 is coated with the first film layer 112, the first tab 1112 extends from one end of the first coated area 1111 in an axial direction Z of the cylindrical battery cell 7, and a surface of the first tab 1112 is not coated with the first film layer 112. The cylindrical battery cell 7 includes a first electrode lead 7a, and the first tab 1112 is electrically connected to the first electrode lead 7a. In the winding direction V, a length of a connection position of the first tab 1112 to the first coated area 1111 is L1, a length of the first coated area 1111 is L0, and 0.8≤L1 / L0≤1.

[0175] As an example, in the winding direction V, a length of the first film layer 112 is equal to a length of the first coated area 1111.

[0176] As an example, after the first polar plate 11 is flattened, both the first film layer 112 and the first coated area 1111 can be rectangular; after the first polar plate 11 is flattened, L0 can be equal to a length of the first coated area 1111, and L1 can be equal to a length of the connection position of the first tab 1112 to the first coated area 1111.

[0177] As an example, the capacity can be 20 Ah, 22 Ah, 25 Ah, 28 Ah, 30 Ah, 35 Ah, 40 Ah, 45 Ah, 50 Ah, 55 Ah, or 60 Ah.

[0178] As an example, the capacity can be a rated capacity of the cylindrical battery cell 7. The rated capacity can be obtained from a manufacturer or seller, as used in the labeling, packaging, user manuals, instructions, advertising, marketing or other support documents for these products, so that the user can use it. The rated capacity can include a number, or other words, phrases, combinations of alphanumeric characters, icons, or signs that indicate to the user how the cylindrical battery cell 7 works.

[0179] In the first polar plate 11, one surface of the first coated area 1111 can be coated with the first film layer 112, or both surfaces of the first coated area 1111 can be coated with the first film layer 112. Both surfaces of the first tab 1112 are not coated with the first film layer 112.

[0180] As an example, L1 / L0 is 0.8, 0.81, 0.82, 0.83, 0.84, 0.85, 0.86, 0.87, 0.88, 0.89, 0.90, 0.91, 0.92, 0.93, 0.94, 0.95, 0.96, 0.97, 0.98, 0.99, or 1.

[0181] The thickness of the first tab 1112 can be the same as or different from the thickness of the first coating area 1111.

[0182] In the winding direction V, the first tab 1112 can be a continuous structure or a discontinuous structure. As an example, the first tab 1112 can also be divided into a plurality of tab segments, and the sum of the lengths of the connection positions of the plurality of tab segments to the first coating area 1111 is L1.

[0183] The cylindrical battery cell 7 has a capacity greater than or equal to 20 Ah, which is conducive to improving the energy density when a plurality of cylindrical battery cells 7 are assembled into a group.

[0184] During charging or discharging, current is transmitted between the first coating area 1111 and the first tab 1112. For a cylindrical battery cell 7 with a larger capacity, the current flowing through the connection position of the first coating area 1111 and the first tab 1112 is larger. The connection position of the first coating area 1111 and the first tab 1112 is close to the first film layer 112, and thus the heat generated by the connection position of the first coating area 1111 and the first tab 1112 under the action of the current is more likely to affect the first film layer 112.

[0185] The embodiments of the present application limit L1 / L0 to be greater than or equal to 0.8, which can increase the overcurrent area of the connection position of the first coating area 1111 and the first tab 1112, reduce the impedance, reduce the heat generation of the connection position of the first coating area 1111 and the first tab 1112, thereby reducing the temperature rise of the first current collector 111 and the first film layer 112, reducing the risk of ion (e.g., lithium ion) precipitation, improving the cycle performance of the cylindrical battery cell 7, reducing the risk of thermal runaway, and improving the reliability of the cylindrical battery cell 7. The embodiments of the present application limit L1 / L0 to be less than or equal to 1, which can reduce the redundancy of the first tab 1112, save space, and reduce the impact of lengthening the first tab 1112 on the energy density of the cylindrical battery cell 7.

[0186] In some embodiments, 0.95≤L1 / L0≤1, which can balance the cycle performance and energy density of the cylindrical battery cell 7 to some extent.

[0187] In some embodiments, 3000 mm ≤ L0≤ 9000 mm. As an example, L0 is 3000 mm, 3500 mm, 4000 mm, 4500 mm, 5000 mm, 5500 mm, 6000 mm, 6500 mm, 7000 mm, 7500 mm, 8000 mm, 8500 mm, or 9000 mm.

[0188] L0 is positively correlated with the length of the first tab 11. The embodiments of the present application limit L0 to be greater than or equal to 3000 mm, which can improve the capacity of the cylindrical battery cell 7. Using the first tab 11 with a larger length can also correspondingly increase the length of the first lug 1112, thereby improving the overcurrent capacity, reducing the impedance, reducing the temperature rise of the first current collector 111 and the first film layer 112, and reducing the risk of ion precipitation, and improving the cycle performance of the cylindrical battery cell 7. When the diameter of the cylindrical battery cell 7 is constant, the longer the first current collector 111 is, the higher the weight proportion of the first current collector 111 in the cylindrical battery cell 7 is. The embodiments of the present application limit L0 to be less than or equal to 9000 mm, which can limit the space and weight occupied by the first current collector 111 and reduce the loss of energy density of the cylindrical battery cell 7.

[0189] As an example, 4500 mm ≤ L0≤ 7000 mm. Limiting the length of the first coating area 1111 to 4500 mm-7000 mm can balance the cycle performance and energy density of the cylindrical battery cell 7 to some extent.

[0190] In some embodiments, 2400 mm ≤ L1≤ 9000 mm. Limiting L1 to be greater than or equal to 2400 mm can improve the overcurrent capacity, reduce the impedance, reduce the temperature rise of the first current collector 111 and the first film layer 112, and reduce the risk of ion precipitation, and improve the cycle performance of the cylindrical battery cell 7. Limiting L1 to be less than or equal to 9000 mm can limit the space and weight occupied by the first current collector 111 and reduce the loss of energy density of the cylindrical battery cell 7.

[0191] As an example, L1 is 2400 mm, 2700 mm, 3000 mm, 3500 mm, 4000 mm, 4500 mm, 5000 mm, 5500 mm, 6000 mm, 6500 mm, 7000 mm, 7500 mm, 8000 mm, 8500 mm, or 9000 mm.

[0192] In some embodiments, 3600 mm ≤ L1≤ 7000 mm.

[0193] In some embodiments, the diameter of the cylindrical battery cell 7 is 40-100 mm, and L0 is 3000-9000 mm. By adopting the first tab 11 with a larger length, the thickness of the first tab 11, i.e., the thickness of the first film layer 112, can be reduced, the impedance can be reduced, the rate of ion extraction or intercalation can be increased, and the fast charging capability of the cylindrical battery cell 7 can be improved.

[0194] In some embodiments, the thickness of the first tab 1112 is equal to that of the first coating area 1111. By adopting the first tab 1112 and the first coating area 1111 with the same thickness, the forming process of the first tab 11 can be simplified.

[0195] In some embodiments, the first tab 1112 and the first coating area 1111 are integrally formed.

[0196] In some embodiments, the sum of the thickness of the first film layer 112 and the thickness of the first coating area 1111 is D1, the thickness of the first coating area 1111 is T1, and 0.17≤T1 / D1≤0.35.

[0197] For example, the first coating area 1111 is provided with the first film layer 112 on both sides, and T1 can be the thickness of the first film layer 112 on one side of the first coating area 1111.

[0198] For example, T1 / D1 can be 0.17, 0.18, 0.19, 0.20, 0.21, 0.22, 0.23, 0.24, 0.25, 0.26, 0.27, 0.28, 0.29, 0.30, 0.31, 0.32, 0.33, 0.34, or 0.35.

[0199] The greater T1 / D1 is, the greater the flow area of the first coating area 1111 is, the lower the impedance of the first coating area 1111 is, and the less heat the first coating area 1111 generates and the lower the temperature rise of the first coating area 1111 in the charging and discharging process are. The smaller T1 / D1 is, the greater the thickness ratio of the first film layer 112 to the first coating area 1111 is, and the higher the capacity of the first film layer 112 is.

[0200] In the embodiments of the present application, T1 / D1 is greater than or equal to 0.17, so as to increase the flow area of the first coating area 1111 or reduce the thickness of the first film layer 112 (reducing the thickness of the first film layer 112 can reduce the capacity of the first film layer 112, and in turn reduce the current flowing through the first coating area 1111 during charging or discharging), thereby reducing the heat generation of the first coating area 1111 during charging and discharging, reducing the temperature rise of the first film layer 112 and the first coating area 1111, improving the cycle performance of the cylindrical battery cell 7, and reducing the risk of thermal runaway. In the embodiments of the present application, T1 / D1 is less than or equal to 0.35, so as to limit the thickness ratio of the first coating area 1111 in the first pole piece 11, and reduce the loss of the capacity of the first pole piece 11. In the embodiments of the present application, T1 / D1 is limited to 0.17-0.35, which can balance the cycle performance and energy density of the cylindrical battery cell 7 to a certain extent.

[0201] In some embodiments, 9 μm ≤ T1 ≤ 17 μm. As an example, T1 is 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, or 17 μm.

[0202] Limiting T1 to be greater than or equal to 9 μm can make the first coating area 1111 have a larger flow area, thereby reducing the impedance, reducing the heat generation of the first coating area 1111 during charging and discharging, reducing the temperature rise of the first film layer 112 and the first coating area 1111, reducing ion precipitation (such as lithium precipitation), improving the cycle performance of the cylindrical battery cell 7, and reducing the risk of thermal runaway. Limiting T1 to be greater than or equal to 17 μm can limit the thickness ratio of the first coating area 1111 in the first pole piece 11, and reduce the loss of the capacity of the first pole piece 11.

[0203] In some embodiments, 11 μm ≤ T1 ≤ 15 μm, which can further balance the cycle performance and energy density of the cylindrical battery cell 7.

[0204] In some embodiments, the sum of the thickness of the first film layer 112 and the thickness of the first coating area 1111 is D1, the thickness of the first film layer 112 is T2, and 0.67 ≤ T2 / D1 ≤ 0.81.

[0205] As an example, D1 = T1 + T2.

[0206] As an example, the thickness of the first pole piece 11 is T1 + 2 × T2.

[0207] As an example, T2 / D1 is 0.67, 0.68, 0.69, 0.70, 0.71, 0.72, 0.73, 0.74, 0.75, 0.76, 0.77, 0.78, 0.79, 0.80, or 0.81.

[0208] T2 / D1 is greater than or equal to 0.67 to increase the thickness ratio of the first film layer 112 in the first tab 11, improve the capacity of the first tab 11, and increase the energy density of the cylindrical battery cell 7. T2 / D1 is less than or equal to 0.81 to limit the thickness ratio of the first film layer 112 to the first coating area 1111, keep the first coating area 1111 with a larger thickness, thereby reducing the impedance, reducing the heat generation of the first coating area 1111 during the charging and discharging process, reducing the temperature rise of the first film layer 112 and the first coating area 1111, reducing ion precipitation, improving the cycle performance of the cylindrical battery cell 7, and reducing the risk of thermal runaway. The embodiments of the present application limit T2 / D1 to 0.67-0.81, which can balance the cycle performance and energy density of the cylindrical battery cell 7 to a certain extent.

[0209] In addition, T2 / D1 is less than or equal to 0.81, which can also improve the rate of ion extraction or embedding and improve the rapid charging capability of the cylindrical battery cell 7.

[0210] In some embodiments, the capacity of the cylindrical battery cell 7 is 25 Ah-50 Ah. For example, the capacity of the cylindrical battery cell 7 is 25 Ah, 26 Ah, 28 Ah, 30 Ah, 32 Ah, 34 Ah, 35 Ah, 36 Ah, 38 Ah, 40 Ah, 42 Ah, 44 Ah, 45 Ah, 46 Ah, 48 Ah, or 50 Ah.

[0211] The cylindrical battery cell 7 has a capacity greater than or equal to 25 Ah, which is beneficial to improve the energy density when a plurality of cylindrical battery cells 7 are assembled into a group. Limiting the capacity C of the cylindrical battery cell 7 to be less than or equal to 50 Ah can limit the charging current of the cylindrical battery cell 7, reduce heat generation, reduce the temperature rise of the first film layer 112 and the first current collector 111, and improve the cycle performance of the cylindrical battery cell 7.

[0212] In some embodiments, the cylindrical battery cell 7 has a rapid charging capability.

[0213] The capacity of the cylindrical battery cell 7 is C Ah. The cylindrical battery cell 7 can be charged at a 2C rate, a 3C rate, or a 4C rate during a partial stage of charging. For example, charging at a 2C rate means charging at a constant current of 2xC A.

[0214] For example, the capacity of the cylindrical battery cell 7 is 25 Ah (i.e., C is 25); at 30°C, the cylindrical battery cell 7 can be charged with a current of 25 A, 50 A, or 75 A during the charging process from 10% SOC to 80% SOC.

[0215] SOC refers to the state of charge of the battery cell.

[0216] Exemplarily, the cylindrical battery monomer is charged to 4.25V at 0.33C constant current at 25°C, and then continues to be charged at 4.25V constant voltage until the charging current decays to 0.05C, at which time the cylindrical battery monomer is at 100% SOC. The cylindrical battery monomer 7 is discharged to 2.5V at a rate of 0.33C, at which time the cylindrical battery monomer is at 0% SOC.

[0217] The discharge capacity A0 is recorded in Ah; according to the charged capacity, the state of charge of the cylindrical battery monomer can be determined, for example, when 0.1A0 is charged from 0% SOC, the cylindrical battery monomer is at 10% SOC.

[0218] In some embodiments, the connection position of the first tab 1112 and the first coating area 1111 is continuously arranged along the winding direction V, which can increase the flow area between the first tab 1112 and the first coating area 1111, reduce the heat generation of the first coating area 1111 and the first tab 1112, reduce the temperature rise of the first film layer 112, and improve the cycle performance of the cylindrical battery monomer 7.

[0219] In some embodiments, the first tab 1112 is continuously arranged along the winding direction V as a whole, which can improve the flow capacity of the first tab 1112, improve the current consistency, and reduce the heat generation.

[0220] In some embodiments, the minimum length of the first tab 1112 along the winding direction V is greater than or equal to 0.8xL0, which can increase the flow area of each area of the first tab 1112, reduce the impedance, reduce the heat generation of the first tab 1112, reduce the temperature rise of the first film layer 112, and improve the cycle performance of the cylindrical battery monomer 7.

[0221] In some embodiments, the first tab 1112 is rectangular after being flattened.

[0222] In some embodiments, the end of the first tab 1112 away from the first coating area 1111 is bent and forms a first layer stack 1112a, the first layer stack 1112a has a multi-layer structure in the axial direction Z of the cylindrical battery monomer 7, and the first layer stack 1112a is electrically connected to the first electrode lead-out part 7a.

[0223] The multi-layer structure of the first layer stack 1112a can transmit current, and the electrical connection between the first layer stack 1112a with the multi-layer structure and the first electrode lead-out part 7a can improve the flow capacity, reduce the impedance, reduce the heat generation, and improve the cycle performance of the cylindrical battery monomer 7.

[0224] In some embodiments, the cylindrical battery cell 7 comprises a first current collecting member 40, which is at least partially located between the first laminated portion 1112a and the first electrode lead-out portion 7a, and is welded to the first laminated portion 1112a and the first electrode lead-out portion 7a, respectively.

[0225] Welding the first laminated portion 1112a with the multi-layer structure and the first current collecting member 40 can not only reduce the risk of false welding, but also increase the welding area of the first tab 1112 and the first current collecting member 40, and improve the overcurrent capacity.

[0226] In some embodiments, in the axial direction Z, the first current collecting member 40 is located on the side of the first laminated portion 1112a facing the first electrode lead-out portion 7a.

[0227] In some embodiments, the first current collecting member 40, the first current collecting member 40, and the first electrode lead-out portion 7a are made of the same material.

[0228] In some embodiments, the first tab 1112 is wound in the winding direction V and forms a plurality of winding turns, and the end portions of at least some of the winding turns are bent towards the middle portion and form the first laminated portion 1112a.

[0229] In some embodiments, the end region of the first tab 1112 away from the first coating area 1111 is bent by a rubbing process or a smoothing process, and forms the first laminated portion 1112a.

[0230] In some embodiments, the first electrode lead-out portion 7a comprises an electrode terminal 30 which is insulatedly arranged on the shell 20, at least a portion of the electrode terminal 30 protrudes from the wall of the shell 20; the first tab 1112 is electrically connected to the electrode terminal 30.

[0231] As an example, the wall can be the end wall 211 of the shell 21, or the end cover 22.

[0232] By protruding at least a portion of the electrode terminal 30, the electrode terminal 30 can be connected to the external busbar, and the exposed area of the electrode terminal 30 can be increased, and the heat dissipation efficiency of the electrode terminal 30 can be improved, so as to reduce the temperature rise of the first tab 1112 and improve the cycle performance of the cylindrical battery cell 7.

[0233] In some embodiments, the thermal conductivity of the electrode terminal 30 is greater than that of the shell 20. The electrode terminal 30 is electrically connected to the first tab 1112, and the electrode terminal 30 has better heat conduction capacity than the shell 20. Therefore, the electrode terminal 30 can quickly conduct the heat of the first tab 1112 out, thereby slowing down the temperature rise of the first tab 1112, reducing the heat impact on the first film layer 112, and improving the cycle performance of the cylindrical battery cell 7.

[0234] In some embodiments, the electrode terminal 30 has a thermal conductivity greater than or equal to 100 W / (m·K).

[0235] In some embodiments, the first tab 11 is a positive tab, and the first current collector 111 is made of aluminum or an aluminum alloy. Aluminum and aluminum alloys have good electrical conductivity and thermal conductivity. Using an aluminum first current collector 111 can reduce impedance, reduce heat generation, and improve the cycle performance of the cylindrical battery cell 7.

[0236] In some embodiments, the first current collector 111 is an aluminum foil.

[0237] In some embodiments, the electrode terminal 30 is made of aluminum or an aluminum alloy.

[0238] In some embodiments, the first current collector member 40 is made of aluminum or an aluminum alloy.

[0239] In some embodiments, the second tab 12 includes a second current collector 121 and a second film layer 122. The second current collector 121 includes a second coated area 1211 and a second tab 1212. The second film layer 122 is coated on the surface of the second coated area 1211. The second tab 1212 extends from one end of the second coated area 1211 along the axial direction Z, and the surface of the second tab 1212 is not coated with the second film layer 122. In the axial direction Z, the first tab 1112 and the second tab 1212 are respectively located at the two ends of the electrode assembly 10. The cylindrical battery cell 7 includes a second electrode lead-out portion 7b, and the second tab 1212 is electrically connected to the second electrode lead-out portion 7b.

[0240] By respectively arranging the first tab 1112 and the second tab 1212 at the two ends of the electrode assembly 10, more space can be provided for the first tab 1112 and the second tab 1212, so that the first tab 1112 and the second tab 1212 can have a larger length, improve the overcurrent capacity, reduce the impedance, and improve the cycle performance of the cylindrical battery cell 7.

[0241] In some embodiments, along the winding direction V, the length of the second coated area 1211 is L3, and the length of the connection position of the second tab 1212 and the second coated area 1211 is L4. 0.8≤L4 / L3≤1.

[0242] As an example, along the winding direction V, the length of the second film layer 122 is equal to the length of the second coated area 1211.

[0243] As an example, after the second tab 12 is flattened, the second film layer 122 and the second coated area 1211 can both be rectangular. After the second tab 12 is flattened, L3 can be equal to the length of the second coated area 1211, and L4 can be equal to the length of the connection position of the second tab 1212 and the second coated area 1211.

[0244] In the second tab 12, one surface of the second coated area 1211 can be coated with the second film layer 122, or both surfaces of the second coated area 1211 can be coated with the second film layer 122. Both surfaces of the second tab 1212 are not coated with the second film layer 122.

[0245] As an example, L4 / L3 is 0.8, 0.81, 0.82, 0.83, 0.84, 0.85, 0.86, 0.87, 0.88, 0.89, 0.90, 0.91, 0.92, 0.93, 0.94, 0.95, 0.96, 0.97, 0.98, 0.99, or 1.

[0246] In the winding direction V, the second tab 1212 can be a continuous structure or a discontinuous structure.

[0247] The embodiments of the present application limit L4 / L3 to be greater than or equal to 0.8, which can increase the flow area of the connection position of the second coated area 1211 and the second tab 1212, reduce the impedance, reduce the heat generation at the connection position of the second coated area 1211 and the second tab 1212, thereby reducing the temperature rise of the second current collector 121 and the second film layer 122, reducing the risk of ion (e.g., lithium ion) precipitation, improving the cycle performance of the cylindrical battery cell 7, reducing the risk of thermal runaway, and improving the reliability of the cylindrical battery cell 7. The embodiments of the present application limit L4 / L3 to be less than or equal to 1, which can reduce the redundancy of the second tab 1212, save space, and reduce the impact of lengthening the second tab 1212 on the energy density of the cylindrical battery cell 7.

[0248] In some embodiments, 0.95≤L4 / L3≤1, which can balance the cycle performance and energy density of the cylindrical battery cell 7 to some extent.

[0249] In some embodiments, 3000mm≤L3≤9000mm. As an example, L3 is 3000mm, 3500mm, 4000mm, 4500mm, 5000mm, 5500mm, 6000mm, 6500mm, 7000mm, 7500mm, 8000mm, 8500mm, or 9000mm.

[0250] In some embodiments, 2400mm≤L4≤9000mm. As an example, L4 is 2400mm, 2700mm, 3000mm, 3500mm, 4000mm, 4500mm, 5000mm, 5500mm, 6000mm, 6500mm, 7000mm, 7500mm, 8000mm, 8500mm, or 9000mm.

[0251] In some embodiments, the first tab 11 is a positive tab, and the second tab 12 is a negative tab. Exemplarily, L3 is greater than L0, and the second film layer 122 can provide embedding space for ions to be extracted from the first film layer 112, thereby reducing the risk of ion precipitation and improving the cycle performance and reliability of the cylindrical battery cell 7.

[0252] In some embodiments, the first tab 11 is a positive tab, and the second tab 12 is a negative tab. The material of the first current collector 111 is aluminum, and the material of the second current collector 121 is copper.

[0253] In some embodiments, the thickness T1 of the first coating area 1111 is greater than the thickness T3 of the second coating area 1211, and the thickness T4 of the first lug 1112 is greater than the thickness T5 of the second lug 1212.

[0254] Because the electrical conductivity of copper is higher than that of aluminum, setting the thickness of the aluminum first coating area 1111 to be greater than the thickness of the copper second coating area 1211 can reduce the difference in electrical conductivity between the first coating area 1111 and the second coating area 1211, improve current consistency, reduce the temperature difference between the first coating area 1111 and the second coating area 1211, and improve the cycle performance of the cylindrical battery cell 7.

[0255] Similarly, setting the thickness of the aluminum first lug 1112 to be greater than the thickness of the copper second lug 1212 can reduce the difference in electrical conductivity between the first lug 1112 and the second lug 1212, improve current consistency, reduce the temperature difference between the first lug 1112 and the second lug 1212, and improve the cycle performance of the cylindrical battery cell 7.

[0256] In some embodiments, t1=t2, t3=t4.

[0257] In some embodiments, L1xt1>L4xt2. The thermal conductivity and electrical conductivity of copper are better than those of aluminum. Setting the flow area of the connection position of the first lug 1112 and the first coating area 1111 to be greater than the flow area of the connection position of the second lug and the second coating area 1211 can reduce the temperature difference between the first current collector 111 and the second current collector 121.

[0258] In some embodiments, the melting point of the outer shell 20 is greater than or equal to 1050℃. Exemplarily, the melting point of the outer shell 20 refers to the melting point under standard atmospheric pressure.

[0259] When the cylindrical battery cell 7 is in thermal runaway, a large amount of heat and gas will be generated inside the electrode assembly 10, and the heat and gas can be discharged through the pressure relief mechanism of the cylindrical battery cell 7. The first tab 1112 has a large length, which will slow down the discharge of heat and gas to some extent, so that the temperature inside the cylindrical battery cell 7 is relatively high; the shell 20 has a high melting point, which can withstand a high temperature, and the use of the shell 20 with a high melting point can reduce the risk of the shell 20 being melted through, realize directional pressure relief of the cylindrical battery cell 7, and reduce the risk of heat spread.

[0260] In some embodiments, the melting point of the shell 20 is greater than or equal to 1300°C, which can be greater than or equal to 1400°C.

[0261] In some embodiments, the tensile strength of the shell 20 is greater than or equal to 300 MPa. For example, the tensile strength of the shell 20 is 400 MPa-1000 MPa.

[0262] For example, the tensile strength of the shell 20 can be measured according to GB / T 228.1-2010 “Metallic Materials-Tensile Testing-Part 1: Method of Test at Room Temperature”.

[0263] When the cylindrical battery cell 7 is in thermal runaway, a large amount of heat and gas will be generated inside the electrode assembly 10, and the heat and gas can be discharged through the pressure relief mechanism of the cylindrical battery cell 7. The first tab 1112 has a large length, which will slow down the discharge of heat and gas to some extent, so that the pressure inside the cylindrical battery cell 7 is relatively high; the use of the shell 20 with a high tensile strength can reduce the risk of the shell 20 being cracked, realize directional pressure relief of the cylindrical battery cell 7, and reduce the risk of heat spread.

[0264] In some embodiments, the shell 20 is a steel shell.

[0265] For example, the shell 21 can be made of steel with a high melting point and high strength, such as low-carbon steel, medium-carbon steel, or stainless steel.

[0266] For example, the end cover 22 can be made of steel with a high melting point and high strength, such as low-carbon steel, medium-carbon steel, or stainless steel.

[0267] The steel shell has a high melting point and strength, which is not easy to break when the cylindrical battery cell 7 is in thermal runaway, thereby improving the reliability of the cylindrical battery cell 7. In the cycle process of the cylindrical battery cell 7, the electrode assembly 10 will swell; the steel shell has high strength and is less deformed under the swelling force of the electrode assembly 10, so the steel shell can effectively limit the deformation of the electrode assembly 10.

[0268] FIG. 13 is a schematic view of a first tab of a cylindrical battery cell in a flattened state according to some embodiments of the present application.

[0269] Referring to FIG. 13, in some embodiments, L1 < L0. The length of the first tab 1112 can be reduced to save the space and weight occupied by the first tab 1112 and improve the energy density of the cylindrical battery cell 7, on the premise that the overcurrent capacity of the connection position of the first tab 1112 and the first coated area 1111 meets the requirements.

[0270] In some embodiments, L1 / L0 is 0.8-0.98, and can be 0.90-0.95.

[0271] FIG. 14 is a schematic view of a first tab of a cylindrical battery cell in a flattened state according to some embodiments of the present application.

[0272] Referring to FIG. 14, in some embodiments, L1 = L0.

[0273] In some embodiments, the first tab 1112 includes a transition portion 1112b and a connection portion 1112c, and the transition portion 1112b connects the first coated area 1111 and the connection portion 1112c. In the winding direction V, the length of the transition portion 1112b is greater than the length of the connection portion 1112c, and at least one end of the transition portion 1112b exceeds the connection portion 1112c.

[0274] For example, in the winding direction V, the length of the connection position of the transition portion 1112b and the first coated area 1111 is L1. Optionally, the length of the transition portion 1112b in the winding direction V is equal to L1.

[0275] In some embodiments, in the axial direction Z, the end of the transition portion 1112b away from the first coated area 1111 does not exceed the separator 13.

[0276] In some embodiments, at least one end of the first tab 1112 in the winding direction V is provided with a notch to reduce the length of the connection portion 1112c in the winding direction V.

[0277] In some embodiments, the minimum length of the connection portion 1112c in the winding direction V is greater than or equal to 0.8 x L1.

[0278] In some embodiments, the connection portion 1112c is connected with the first current collecting member 40.

[0279] In some embodiments, the end of the connection portion 1112c away from the transition portion 1112b is bent and forms a first stacking portion.

[0280] In some embodiments, in the winding direction V, both ends of the transition portion 1112b exceed the connection portion 1112c.

[0281] In some embodiments, both sides of the connection portion 1112c in the winding direction V are provided with notches J.

[0282] The electrode assembly 10 has a central hole in the middle after being wound into shape. The central hole can serve as a passage for electrolyte flow, thereby improving the electrolyte's infiltration effect on the electrode assembly 10.

[0283] The notch J is arranged inside the connecting portion 1112c, which can make the connecting portion 1112c lean outward and reduce the risk of the connecting portion 1112c blocking the central hole during the bending process. The notch J is arranged outside the connecting portion 1112c, which can reduce the risk of the sharp corner of the tail end of the connecting portion 1112c puncturing other components.

[0284] In some embodiments, the connecting portion 1112c is trapezoidal after the first tab 1112 is flattened; the length of the connecting portion 1112c gradually decreases in a direction away from the transition portion 1112b.

[0285] FIG. 15 is a schematic view of a first electrode sheet of a cylindrical battery cell in a flattened state according to some embodiments of the present application.

[0286] Referring to FIG. 15, in some embodiments, the first tab 1112 includes a transition portion 1112b and a plurality of first sub-tabs 1112d arranged at intervals in the winding direction V, the transition portion 1112b being connected to the first coating area 1111, the first sub-tabs 1112d being connected to one end of the transition portion 1112b away from the first coating area 1111, and the connection position of the transition portion 1112b to the first coating area 1111 being arranged continuously in the winding direction V.

[0287] The plurality of first sub-tabs 1112d can bend inward in the radial direction of the cylindrical battery cell 7 when pressed, so that the bent portions of some of the first sub-tabs 1112d are stacked in the axial direction Z and form a multi-layer structure. The multi-layer structure can improve the overcurrent capacity, reduce the impedance, reduce the heat generation, and improve the cycle performance of the cylindrical battery cell 7. The plurality of first sub-tabs 1112d are not constrained to each other in the winding direction V, which makes it easy to achieve directional bending of the first sub-tabs 1112d and helps to improve the morphology of the multi-layer structure.

[0288] In some embodiments, along the winding direction V, the sum of the lengths of the connection positions of the plurality of first sub-tabs 1112d to the transition portion 1112b is L2, and the length of the connection position of the transition portion 1112b to the first coating area 1111 is L1. L2 and L1 satisfy: 0.6≤L2 / L1≤0.95.

[0289] Exemplarily, the length of the connection position of each first sub-tab 1112d and the transition portion 1112b is L21; the lengths of the connection positions of the plurality of first sub-tabs 1112d and the transition portion 1112b can be the same or different, in some examples, the lengths of the connection positions of the plurality of first sub-tabs 1112d and the transition portion 1112b are the same; in other examples, the lengths of the connection positions of the plurality of first sub-tabs 1112d and the transition portion 1112b gradually increase along the winding direction V.

[0290] Exemplarily, L2 / L1 is 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, or 0.95.

[0291] The embodiments of the present application limit L2 / L1 to 0.6-0.95, which can increase the flow area of the connection position of the first sub-tab 1112d and the transition portion 1112b, reduce the impedance, reduce the heat generation of the connection position of the first sub-tab 1112d and the transition portion 1112b, thereby reducing the temperature rise of the first current collector 111 and the first film layer 112, reducing the risk of ion (e.g., lithium ion) precipitation, improving the cycle performance of the cylindrical battery cell 7, reducing the risk of thermal runaway, and improving the reliability of the cylindrical battery cell 7. Limiting L2 / L1 to less than or equal to 0.95 can reduce the difficulty of bending the first sub-tab 1112d, reduce the risk of tearing the first sub-tab 1112d, and help improve the morphology of the first tab 1112.

[0292] In some embodiments, L1=L0.

[0293] In some embodiments, the first sub-tab 1112d can be formed by a die-cutting process.

[0294] In some embodiments, the sum of the minimum dimensions of the plurality of first sub-tabs 1112d along the winding direction V is greater than or equal to 0.8xL1.

[0295] In some embodiments, after the first tab 1112 is flattened, the first sub-tab 1112d is trapezoidal and the transition portion 1112b is rectangular.

[0296] FIG. 16 is a schematic view of a first tab of a cylindrical battery cell in a flattened state according to some embodiments of the present application.

[0297] Referring to FIG. 16, in some embodiments, the first tab 1112 includes a plurality of tab segments 1112e, and the plurality of tab segments 1112e are arranged at intervals along the winding direction V.

[0298] Exemplarily, the length of the connection position of each tab segment 1112e with the first coating area 1111 is L5. The lengths L5 of the plurality of tab segments 1112e can be the same or different.

[0299] The sum of the lengths of the connection positions of the plurality of tab segments 1112e with the first coating area 1111 is L1.

[0300] FIG. 17 is a cross-sectional view of an electrode assembly of a cylindrical battery cell according to some embodiments of the present application; FIG. 18 is an enlarged view of the dashed box in FIG. 17; and FIG. 19 is a schematic view of a separator of an electrode assembly of a cylindrical battery cell according to some embodiments of the present application.

[0301] Referring to FIGS. 5, 17-19, in some embodiments, the electrode assembly 10 further includes a separator 13 that is wound along the winding direction V and separates the first electrode tab 11 and the second electrode tab 12. The separator 13 includes a base 131 having two first surfaces 131a oppositely arranged along the thickness direction of the base 131, and a plurality of support portions 132 protruding from at least one of the first surfaces 131a to form a gap G between the first electrode tab 11 and the second electrode tab 12.

[0302] As an example, the plurality of support portions 132 are dispersedly arranged on the first surface 131a.

[0303] In some examples, one of the first surfaces 131a of the base 131 is provided with the plurality of support portions 132. Of course, the first surface 131a of the base 131 that is inwardly facing along the radial direction of the cylindrical battery cell can be provided with the plurality of support portions 132, or the first surface 131a of the base 131 that is outwardly facing along the radial direction of the cylindrical battery cell can be provided with the plurality of support portions 132.

[0304] In other examples, both of the first surfaces 131a of the base 131 are provided with the plurality of support portions 132.

[0305] As an example, the first film layer of the first electrode tab 11 can be in contact with the support portions 132 of the portion of the separator 13, and / or the second film layer of the second electrode tab 12 can be in contact with the support portions 132 of the portion of the separator 13.

[0306] As an example, the gap G can be a space between the first electrode tab 11 and the second electrode tab 12 that is not filled by the separator 13.

[0307] The support portions 132 can be rigid or flexible.

[0308] In the embodiments of the present application, the cylindrical battery cell has a high capacity; as the capacity increases, the electrode assembly 10 will generate a greater swelling force when charging. During the cycling process of the cylindrical battery cell 7, the gap G can provide space for the expansion of the electrode sheet, reduce the pressure between the first electrode sheet 11 and the second electrode sheet 12, thereby reducing the extrusion of the electrolyte in the internal pores of the first film layer and the internal pores of the second film layer, reducing the concentration difference of the electrolyte in each region of the electrode sheet, and improving the cycling performance of the cylindrical battery cell 7 with a larger capacity. The gap G can reduce the swelling amount of the electrode assembly 10, thereby reducing the extrusion of the housing 20, reducing the risk of deformation and cracking of the housing 20, and improving the reliability of the cylindrical battery cell 7. By providing the gap G, the increase in the swelling force caused by increasing the capacity of the cylindrical battery cell 7 can be reduced.

[0309] The gap G can also accommodate electrolyte to improve the wettability of the electrolyte to the first electrode sheet and the second electrode sheet, and improve the cycling performance of the cylindrical battery cell.

[0310] In addition, when ion precipitation occurs in the negative electrode sheet during the cycling process, such as lithium precipitation, the gap G can provide space for the deformation of the separator 13, so that the separator 13 can release the pressure exerted by the lithium dendrites through deformation, thereby to some extent avoiding the separator 13 being pierced, reducing the risk of short circuit, and improving the reliability.

[0311] In some embodiments, the negative active material includes a carbon-based material. The carbon-based material has high cycling stability, which can improve the cycling performance of the cylindrical battery cell.

[0312] In some embodiments, the support portion 132 is configured to be compressible. During the cycling process of the cylindrical battery cell 7, the support portion 132 can be compressed when under pressure, thereby providing more expansion space for the electrode sheet. The compressible support portion 132 can release stress through compression deformation, thereby reducing the risk of the first electrode sheet 11 or the second electrode sheet 12 being bruised by the support portion 132, and improving the reliability.

[0313] In some embodiments, the plurality of support portions 132 includes a first support portion 132a and a second support portion 132b, and the height H1 of the first support portion 132a protruding from the first surface 131a is greater than the height H2 of the second support portion 132b protruding from the first surface 131a.

[0314] The first support portion 132a can be one or more. The second support portion 132b can be one or more. Alternatively, both the first support portion 132a and the second support portion 132b are a plurality.

[0315] The first support portion 132a has a large height, which can support the first tab 11 or the second tab 12 to form a large gap G, thereby providing more space for the expansion of the tab. The second support portion 132b has a small height, and occupies a small space. As the tab expands, the gap G gradually decreases; the second support portion 132b can be pressed after the tab expands to a certain extent, thereby reducing the pressure on the tab in the initial stage of expansion. When the second support portion 132b is pressed, the second support portion 132b can slow down the expansion of the tab to some extent, reduce the electrolyte squeezed out by the tab, and improve the cycle performance of the cylindrical battery cell 7.

[0316] In some embodiments, the first support portion 132a is a plurality, and the second support portion 132b is a plurality.

[0317] In some embodiments, the height of the first support portion 132a is 1.1 to 15 times, optionally 2 to 7 times, the height of the second support portion 132b.

[0318] In some embodiments, the support portion 132 includes an organic particle P disposed on the base portion 131.

[0319] The support portion 132 is a plurality, and correspondingly, the organic particle P is a plurality.

[0320] The organic particle P can protrude from the base portion 131 as a whole. Alternatively, part of the organic particle is embedded in the base portion 131, and part of the organic particle protrudes from the base portion 131.

[0321] The organic particle P can play a supporting role to form the gap G. When the cylindrical battery cell 7 experiences thermal runaway, the organic particle P can form a gel film structure at high temperature, thereby reducing the diffusion channel of active ions and delaying the time of thermal spread, thereby improving the reliability of the cylindrical battery cell 7.

[0322] Exemplarily, the organic particle P can be formed on the separator 13 by coating. Forming the support portion 132 by coating the organic particle P can simplify the molding process.

[0323] In some embodiments, the plurality of organic particles P includes a first organic particle P1 and a second organic particle P2, and the number average particle size of the first organic particle P1 is greater than the number average particle size of the second organic particle P2.

[0324] It should be noted that the number average particle size of the organic particle is the arithmetic mean of the particle size of the organic particle counted by the number of the organic particle. The particle size of the organic particle can refer to the distance between the two most distant points on the organic particle.

[0325] The first organic particles P1 with a larger number average particle size can support the first or second electrode sheet 11 or 12 to form a larger gap G, thereby providing more space for the expansion of the electrode sheet. The second organic particles P2 with a smaller number average particle size can be compressed after the electrode sheet expands to a certain extent, which can reduce the pressure on the electrode sheet in the initial stage of expansion. When the second organic particles P2 are compressed, the second organic particles P2 can slow down the expansion of the electrode sheet to a certain extent, reduce the electrolyte squeezed out by the electrode sheet, and improve the cycle performance of the cylindrical battery cell 7.

[0326] In some embodiments, the plurality of support portions 132 includes a first support portion 132a and a second support portion 132b, the first support portion 132a protruding from the first surface 131a by a height greater than the second support portion 132b protruding from the first surface 131a. The plurality of organic particles P includes first organic particles P1 and second organic particles P2; the first support portion 132a includes the first organic particles P1, and the second support portion 132b includes the second organic particles P2.

[0327] By setting the first organic particles P1 and the second organic particles P2 with different number average particle sizes, the first support portion 132a and the second support portion 132b with different heights can be formed. The first support portion 132a has a larger height, which can support the first or second electrode sheet 11 or 12 to form a larger gap G, thereby providing more space for the expansion of the electrode sheet. The second support portion 132b can be compressed after the electrode sheet expands to a certain extent, which can reduce the pressure on the electrode sheet in the initial stage of expansion. When the second support portion 132b is compressed, the second support portion 132b can slow down the expansion of the electrode sheet to a certain extent, reduce the electrolyte squeezed out by the electrode sheet, and improve the cycle performance of the cylindrical battery cell 7.

[0328] In some embodiments, the number average particle size of the first organic particles P1 is >10 μm, and the number average particle size of the second organic particles P2 is 2 μm-10 μm.

[0329] In some embodiments, the number average particle size of the first organic particles P1 is 12 μm-25 μm. For example, the number average particle size of the first organic particles P1 can be 12 μm, 13 μm, 15 μm, 16 μm, 18 μm, 20 μm, 21 μm, 22 μm, 24 μm, or 25 μm.

[0330] In some embodiments, the number average particle size of the second organic particles P2 is 2 μm-9 μm. For example, the number average particle size of the first organic particles 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.

[0331] In some embodiments, the ratio of the number average particle diameter of the first organic particles P1 to the number average particle diameter of the second organic particles P2 is greater than or equal to 1.5.

[0332] In some embodiments, the first organic particles P1 are secondary particles.

[0333] In some embodiments, the second organic particles P2 are primary particles.

[0334] It should be noted that primary particles and secondary particles have meanings well known in the art. Primary particles refer to particles that have not formed an agglomerated state. Secondary particles refer to agglomerated particles formed by aggregation of two or more primary particles.

[0335] In some embodiments, the plurality of organic particles P includes first organic particles P1 including one or more of a homopolymer or copolymer of a fluorine-containing alkenyl monomer unit, a homopolymer or copolymer of an alkenyl monomer unit, a homopolymer or copolymer of an unsaturated nitrile monomer unit, a homopolymer or copolymer of an alkylene oxide monomer unit, and a modified compound of each of the above homopolymers or copolymers.

[0336] In some embodiments, the fluorine-containing alkenyl monomer unit can be selected from one or more of difluoroethylene, vinylidene fluoride, trifluoroethylene, chlorotrifluoroethylene, tetrafluoroethylene, hexafluoropropylene.

[0337] In some embodiments, the alkenyl monomer unit can be selected from one or more of ethylene, propylene, butadiene, isoprene, and the like.

[0338] In some embodiments, the unsaturated nitrile monomer unit can be selected from one or more of acrylonitrile, methacrylonitrile, and the like.

[0339] In some embodiments, the alkylene oxide monomer unit can be selected from one or more of ethylene oxide, propylene oxide, and the like.

[0340] In some embodiments, the first organic particles P1 include one or more of polytetrafluoroethylene, polychlorotrifluoroethylene, polyfluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, polyacrylonitrile, polyethylene oxide, a copolymer of different fluorine-containing alkenyl monomer units, a copolymer of a fluorine-containing alkenyl monomer unit and an alkenyl monomer unit, a copolymer of a fluorine-containing alkenyl monomer unit and an acrylic monomer unit, a copolymer of a fluorine-containing alkenyl monomer unit and an acrylate monomer unit, and a modified compound of each of the above homopolymers or copolymers.

[0341] In some embodiments, the first organic particles P1 can include one or more of a vinylidene fluoride-trifluoroethylene copolymer, a vinylidene fluoride-hexafluoropropylene copolymer, a vinylidene fluoride-trifluoroethylene-hexafluoropropylene copolymer, a vinylidene fluoride-hexafluoropropylene-acrylic acid copolymer, a vinylidene fluoride-hexafluoropropylene-acrylate copolymer, and a modified compound of the above copolymers.

[0342] In some embodiments, the plurality of organic particles P includes second organic particles P2 including one or more of a homopolymer or a copolymer of an acrylate monomer unit, a homopolymer or a copolymer of an acrylic monomer unit, a homopolymer or a copolymer of a styrene monomer unit, a polyurethane compound, a rubber compound, and a modified compound of each of the above homopolymers or copolymers.

[0343] In some embodiments, the second organic particles P2 include one or more of a copolymer of an acrylate monomer unit and a styrene monomer unit, a copolymer of an acrylic monomer unit and a styrene monomer unit, a copolymer of an acrylic monomer unit-acrylate monomer unit-styrene monomer unit, a copolymer of a styrene monomer unit and an unsaturated nitrile monomer unit, a copolymer of a styrene monomer unit-olefin-based monomer unit-unsaturated nitrile monomer unit, and a modified compound of the above copolymers.

[0344] In some embodiments, the acrylate monomer unit can be selected from one or more of methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, methyl methacrylate, butyl methacrylate, isooctyl methacrylate, and the like.

[0345] In some embodiments, the acrylic monomer unit can be selected from one or more of acrylic acid, methacrylic acid, and the like.

[0346] In some embodiments, the styrene monomer unit can be selected from one or more of styrene, methylstyrene, and the like.

[0347] In some embodiments, the unsaturated nitrile monomer unit can be selected from one or more of acrylonitrile, methacrylonitrile, and the like.

[0348] In some embodiments, the second organic particles P2 can include one or more of a butyl acrylate-styrene copolymer, a butyl methacrylate-isooctyl methacrylate copolymer, an isooctyl methacrylate-styrene copolymer, a methacrylate-methacrylic acid-styrene copolymer, a methyl acrylate-isooctyl methacrylate-styrene copolymer, a butyl acrylate-isooctyl acrylate-styrene copolymer, a butyl acrylate-isooctyl methacrylate-styrene copolymer, a butyl methacrylate-isooctyl acrylate-styrene copolymer, a butyl methacrylate-isooctyl methacrylate-styrene copolymer, a styrene-acrylonitrile copolymer, a styrene-butadiene-acrylonitrile copolymer, a methyl acrylate-styrene-acrylonitrile copolymer, an isooctyl methacrylate-styrene-acrylonitrile copolymer, a styrene-vinyl acetate copolymer, a styrene-vinyl acetate-pyrrolidone copolymer, and modified compounds of each of the above materials.

[0349] In some embodiments, the base 131 includes a base film 1311 and an inorganic particle layer 1312 disposed on the base film 1311, and the organic particles P at least partially protrude from the inorganic particle layer 1312.

[0350] The inorganic particle layer 1312 includes a plurality of inorganic particles, and sufficient and unevenly distributed voids are formed between the inorganic particles and the organic particles, which can improve the air permeability of the separator, and the cylindrical battery cell has better cycle performance and reliability.

[0351] In some embodiments, the inorganic particles can be coated on the base film 1311 first to form the inorganic particle layer 1312, and then the plurality of organic particles can be coated on the inorganic particle layer 1312. In other embodiments, the inorganic particles and the organic particles can be mixed together and then coated on the base film 1311.

[0352] In some examples, one surface of the base film 1311 is coated with a coating layer including the inorganic particle layer 1312 and the plurality of organic particles P, and the other surface of the base film 1311 can be uncoated or coated with the inorganic particle layer 1312. In other examples, both surfaces of the base film 1311 are coated with a coating layer including the inorganic particle layer 1312 and the organic particles P.

[0353] Sufficient and unevenly distributed voids are formed between the inorganic particles and the organic particles P, which can improve the air permeability of the separator 13, and the cylindrical battery cell 7 has better cycle performance and reliability. The organic particles P can support the first electrode sheet 11 or the second electrode sheet 12 to increase the gap G and provide space for the expansion of the electrode sheet.

[0354] In some embodiments, the inorganic particles can include one or more of boehmite (γ-AlOOH), aluminum oxide (Al2O3), barium sulfate (BaSO4), magnesium oxide (MgO), magnesium hydroxide (Mg(OH)2), silicon dioxide (SiO2), tin dioxide (SnO2), titanium oxide (TiO2), calcium oxide (CaO), zinc oxide (ZnO), zirconium oxide (ZrO2), yttrium oxide (Y2O3), nickel oxide (NiO), cerium oxide (CeO2), zirconium titanate (SrTiO3), barium titanate (BaTiO3), magnesium fluoride (MgF2).

[0355] In some embodiments, the volume average particle size Dv50 of the inorganic particles is ≤ 2.5 μm; for example, the particle size of the inorganic particles can be 0.5 μm-2.5 μm, 1.5 μm-2.5 μm, 0.3 μm-0.7 μm, etc.

[0356] In some embodiments, the surface of the base film 1311 facing the first electrode tab 11 is coated with a coating layer comprising the inorganic particle layer 1312 and a plurality of organic particles P, and / or, the surface of the base film 1311 facing the second electrode tab 12 is coated with a coating layer comprising the inorganic particle layer 1312 and a plurality of organic particles P.

[0357] In some embodiments, the gap G extends along the winding direction V of the electrode assembly 10, and the gap G has a winding starting end E1 and a winding ending end E2.

[0358] The gap G is wound into multiple turns along the winding direction V.

[0359] As an example, the first electrode tab 11 has a first winding starting end E3 and a first winding ending end E4, and the second electrode tab 12 has a second winding starting end E5 and a second winding ending end E6.

[0360] In some embodiments, the first electrode tab 11 is a positive electrode tab, and the second electrode tab 12 is a negative electrode tab. Along the winding direction V, the second winding ending end E6 exceeds the first winding ending end E4; along the opposite direction of the winding direction V, the second winding starting end E5 exceeds the first winding starting end E3. The second electrode tab 12 exceeds the first electrode tab 11 at both ends along the winding direction V, and the second electrode tab 12 can provide an intercalation space for the active ions released from the first electrode tab 11, thereby reducing the risk of ion release. In the radial direction of the cylindrical battery cell, the winding starting end E1 of the gap G corresponds to the first winding starting end E3, and the winding ending end E2 of the gap G corresponds to the first winding ending end E4.

[0361] In some embodiments, the radial dimension of at least part of the gap G is 5 μm-60 μm.

[0362] As an example, the radial dimension of the gap G can be the dimension of the gap G along the radial direction of the cylindrical battery cell. The radial dimensions W of the gap G at different positions can be the same or different.

[0363] Optionally, the radial dimension W of each part of the gap G is 5 μm-60 μm.

[0364] Optionally, the radial dimension W of the gap G can be 5 μm, 6 μm, 8 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm, 60 μm or a range formed by any two of the above values.

[0365] As an example, the radial dimension of the gap G can be measured in the following manner:

[0366] Discharge the cylindrical battery cell to the lower limit cut-off voltage (for example, 2.5 V);

[0367] Use the CT (Computed Tomography) technology to obtain an image of the cross section of the electrode assembly by X-ray, and the cross section is perpendicular to the axial direction of the cylindrical battery cell;

[0368] Based on the image, measure the distance D1 between the outer surface of the first electrode sheet of the 6th layer and the inner surface of the first electrode sheet of the 10th layer in the radial direction of the electrode assembly;

[0369] Disassemble the cylindrical battery cell and measure the thickness t1 of the first electrode sheet, the thickness t2 of the second electrode sheet and the thickness t3 of the separator.

[0370] There are 3 layers of first electrode sheets, 4 layers of second electrode sheets and 8 layers of separators between the outer surface of the first electrode sheet of the 6th layer and the inner surface of the first electrode sheet of the 10th layer, and 8 layers of gaps are formed between the outer surface of the first electrode sheet of the 6th layer and the inner surface of the first electrode sheet of the 10th layer. W=(D1-3×t1-4×t2-8×t3) / 8.

[0371] It is explained here that the thickness t3 is measured at the part of the separator where the support part is not arranged, that is, the thickness t3 is the thickness of the base part of the separator.

[0372] The embodiment of the present application limits the radial dimension W of the gap G to be greater than or equal to 5 μm, which can provide space for the expansion of the electrode sheet, reduce the expansion force, improve the cycle performance of the cylindrical battery cell 7, and reduce the risk of deformation and cracking of the shell 20. The embodiment of the present application limits the radial dimension W of the gap G to be less than or equal to 50 μm, so as to shorten the ion migration path between the first electrode sheet 11 and the second electrode sheet 12, reduce the internal resistance of the cylindrical battery cell 7, reduce the heat generation, and reduce the influence of the gap G on the energy density.

[0373] FIG. 20 is a schematic view of a partial cross section of an electrode assembly of a cylindrical battery cell according to some embodiments of the application; FIG. 21 is a schematic view of a separator of an electrode assembly of a cylindrical battery cell according to some embodiments of the application.

[0374] Referring to FIGS. 20 and 21, in some embodiments, the separator 13 has a plurality of support portions 132 on both sides thereof. The gap G includes a first gap G1 formed between the first tab 11 and the separator 13, and a second gap G2 formed between the second tab 12 and the separator 13.

[0375] As an example, the first gap G1 has a radial dimension W1, and the second gap G2 has a radial dimension W2. The radial dimension W of the gap G is W1+W2.

[0376] In the thickness direction of the separator 13, the support portions 132 on both sides of the separator 13 can or can not overlap.

[0377] By providing a plurality of support portions 132 on both sides of the separator 13, the gap G can be increased, providing more space for expansion of the tabs.

[0378] In some embodiments, the base film 1311 has a coating layer including inorganic particles 1312 and a plurality of organic particles P on both sides thereof.

[0379] FIG. 22 is a schematic view of a partial cross section of an electrode assembly of a cylindrical battery cell according to some embodiments of the application. FIG. 17 shows a circle of first tabs, a circle of second tabs, and a circle of separators.

[0380] Referring to FIGS. 17 and 22, in some embodiments, the radial dimension of the portion of the gap G near the winding start end El is greater than or equal to the radial dimension of the portion of the gap G near the winding end E2.

[0381] In embodiments of the application, the radial dimensions of different portions of the gap G along the winding direction V are compared in the same cross section perpendicular to the axial direction Z.

[0382] The “portion of the gap G near the winding start end El” does not require extending from the winding start end El. As an example, the “portion of the gap G near the winding start end El” can extend from a position 1-5 windings away from the winding start end El in the winding direction V.

[0383] The “portion of the gap G near the winding end E2” does not require extending to the winding end E2 in the winding direction V. As an example, the “portion of the gap G near the winding end E2” can have a tail end in the winding direction V that is 1-5 windings away from the winding end E2.

[0384] In the embodiments of the present application, the portion of the gap G close to the winding start end E1 has a larger radial dimension to provide more expansion space for the jelly-roll 10 in the middle part, reduce the risk of the jelly-roll 10 collapsing in the middle part due to expansion, and improve the cycle performance of the cylindrical battery cell 7.

[0385] In some embodiments, the gap G extends along the winding direction V and is wound into n turns, each turn being defined as a winding turn, and n≥20. The average value of the radial dimension of the 5th-9th winding turns is greater than the average value of the radial dimension of the n-9th-n-5th winding turns.

[0386] It is explained herein that n does not require to be an integer, in other words, the 1st-n-1th winding turns are all complete turns; the portion from the end of the n-1th winding turn to the winding end E2 can or can not be a complete turn, for example, 1 / 4 turn, 1 / 2 turn or 3 / 4 turn.

[0387] In the embodiments of the present application, the portion of the gap G close to the winding start end E1 has a larger radial dimension to provide more expansion space for the jelly-roll 10 in the middle part, reduce the risk of the jelly-roll 10 collapsing in the middle part due to expansion, and improve the cycle performance of the cylindrical battery cell 7.

[0388] In some embodiments, the radial dimension of at least part of the gap G gradually decreases along the winding direction V. The radial dimension of the gap G changes gently, reduces the sudden change of the radial dimension of the gap G, reduces the stress concentration of the second jelly-roll 12, and improves the cycle performance of the cylindrical battery cell 7.

[0389] FIG. 23 is a partial cross-sectional view of an electrode assembly of a cylindrical battery cell according to some embodiments of the present application.

[0390] Referring to FIG. 23, in some embodiments, the gap G includes a middle region C1 and two end regions C2 arranged along the axial direction Z, the middle region C1 being located between the two end regions C2, and the radial dimension of the middle region C1 being smaller than the radial dimension of the end region C2.

[0391] In the embodiments of the present application, the radial dimension of the middle region C1 and the radial dimension of the end region C2 are compared in a cross section of a winding turn parallel to the axial direction Z.

[0392] The gap G has a first end E7 and a second end E8 oppositely arranged along the axial direction Z; the dimension of the gap G along the axial direction Z is defined as L, i.e., the distance between the first end E7 and the second end E8 along the axial direction Z is K.

[0393] The end region C2 is a region having a certain size in the axial direction Z. One end region C2 is a region extending from the first end E7 to the second end E8 by a length K1, and the other end region C2 is a region extending from the second end E8 to the first end E7 by the length K1; the middle region C1 includes a region extending from the middle section S to the first end E7 by a length K2 and a region extending from the middle section S to the second end E8 by the length K2. The middle section S is a section perpendicular to the axial direction Z; in the axial direction Z, the distance between the middle section S and the first end E7 is equal to the distance between the middle section S and the second end E8.

[0394] Exemplarily, K1 / K is 0.1-0.3, and can be 0.2. Exemplarily, K2 / K is 0.03-0.2, and can be 0.1.

[0395] Exemplarily, K1 can be 20 mm, and K2 can be 5 mm.

[0396] Exemplarily, the minimum radial dimension of the end region C2 is greater than the maximum radial dimension of the middle region C1.

[0397] In the embodiments of the present application, the end region C2 has a larger radial dimension, so as to facilitate the electrolyte to enter the gap G, improve the electrolyte wetting effect on the electrode sheet, and improve the cycle performance of the cylindrical battery cell 7.

[0398] In some embodiments, the radial dimension of the middle region is 5 μm-60 μm, and can be 10 μm-30 μm.

[0399] In some embodiments, the gap G further includes a transition region C3 connecting the middle region C1 and the end region C2.

[0400] In some embodiments, in the direction from the end region C2 to the middle region C1, the radial dimension of the gap G gradually decreases, so as to reduce the sudden change of the radial dimension of the gap G, reduce the stress concentration of the second electrode sheet 12, and improve the cycle performance of the cylindrical battery cell 7.

[0401] In some embodiments, in the radial direction of the cylindrical battery cell, a part of the plurality of support portions 132 is located between the first tab 1112 and the base 131.

[0402] The first tab 1112 generates heat when current passes through, and the support portion 132 can separate at least part of the first tab 1112 from the base 131, thereby reducing the heat conducted to the base 131, reducing the deformation of the base 131 due to high temperature, reducing the risk of conduction of the first electrode sheet and the second electrode sheet, and improving the reliability of the cylindrical battery cell.

[0403] In some embodiments, in the radial direction of the cylindrical battery cell, a part of the plurality of support portions 132 is located between the second tab and the base 131.

[0404] FIG. 24 is a cross-sectional view of a cylindrical battery cell according to some embodiments of the present application; and FIG. 25 is an enlarged view of the circle in FIG. 24.

[0405] Referring to FIGS. 24 and 25, in some embodiments, the housing 20 includes a shell 21 and an end cap 22, the shell 21 including an integrally formed side wall 212 surrounding the electrode assembly 10 and an end wall 211 opposite the end cap 22 along an axial direction Z of the cylindrical battery cell 7, and the end cap 22 being sealingly connected to the side wall 212.

[0406] The end cap 22 can be insulated from the side wall 212 or can be electrically connected.

[0407] The shell 21 has an opening at an end away from the end wall 211, and the end cap 22 covers the opening of the shell 21.

[0408] In some embodiments, the first tab 1112 is included in the first electrode tab 11, and the second tab 1212 is included in the second electrode tab 12. The first electrode lead 7a includes an electrode terminal 30 insulated from the end wall 211, the first tab 1112 is electrically connected to the electrode terminal 30, and the second tab 1212 is electrically connected to the end wall 211.

[0409] As an example, the second tab 1212 is indirectly connected to the end wall 211 through the end cap 22, the side wall 212, or other components.

[0410] As an example, the end wall 211 can be the second electrode lead 7b.

[0411] The electrode terminal 30 and the end wall 211 can be two exposed electrodes of the cylindrical battery cell 7, and the electrode terminal 30 and the end wall 211 are located on the same side, which facilitates assembly of a plurality of cylindrical battery cells 7 into a group and simplifies the battery structure.

[0412] In some embodiments, the cylindrical battery cell 7 further includes a first current collecting member 40 located on a side of the first tab 1112 facing the end wall 211 and connected to the first tab 1112. The electrode terminal 30 is abutted against and connected to a surface of the first current collecting member 40 facing the end wall 211.

[0413] The first current collecting member 40 can serve as an adapter to achieve electrical connection between the first tab 1112 and the electrode terminal 30.

[0414] In some embodiments, the first current collecting member 40 is in a circular ring shape.

[0415] In some embodiments, the electrode terminal 30 is provided with a terminal recess 31 on a side away from the first current collecting member 40. A bottom wall of the terminal recess 31 is welded to the first current collecting member 40.

[0416] By providing the terminal recess 31, the thickness of the bottom wall of the terminal recess 31 can be reduced, the power required for welding the electrode terminal 30 from the outside to the first current collecting member 40 can be reduced, the risk of particles generated by welding falling into the case 20 can be reduced, and the reliability of the cylindrical battery cell 7 can be improved.

[0417] In some embodiments, the side of the terminal recess 31 facing the first current collecting member 40 is provided with the terminal recess 31, and the bottom wall of the terminal recess 31 is welded to the first current collecting member 40.

[0418] By providing the terminal recess 31, the thickness of the bottom wall of the terminal recess 31 can be reduced, the power required for welding the electrode terminal 30 from the outside to the first current collecting member 40 can be reduced, the risk of particles generated by welding falling into the case 20 can be reduced, and the reliability of the cylindrical battery cell 7 can be improved. By providing the terminal recess 31 on the inner side of the electrode terminal 30, the internal space of the cylindrical battery cell 7 can also be increased.

[0419] In some embodiments, the side of the electrode terminal 30 facing the first current collecting member 40 is provided with one terminal recess 31, and the side of the electrode terminal 30 facing away from the first current collecting member 40 is provided with another terminal recess 31; the bottom surfaces of the two terminal recesses 31 correspondingly welded to the first current collecting member 40.

[0420] In some embodiments, the bottom wall of the terminal recess 31 is provided with a through hole 32, which can be used for injecting electrolyte.

[0421] In some embodiments, the cylindrical battery cell 7 further comprises a cover plate 50 connected to the electrode terminal 30 and used to separate the through hole 32 from the external space of the cylindrical battery cell 7.

[0422] In some embodiments, at least part of the cover plate 50 is accommodated in the terminal recess 31. In some embodiments, the first electrode lead-out portion 7a comprises the cover plate 50 and the electrode terminal 30.

[0423] In some embodiments, the electrode terminal 30 is riveted to the end wall 211.

[0424] In some embodiments, the first tab 1112 is located at one end of the first tab 11 facing the end wall 211, and the second tab 1212 is located at one end of the second tab 12 facing the end cover 22. The cylindrical battery cell 7 further comprises a second current collecting member 60 connected to the second tab 1212; the second current collecting member 60 is connected to at least one of the end cover 22 and the side wall 212.

[0425] In some examples, the second current collecting member 60 is connected to the end cap 22, and the end cap 22 is electrically connected to the side wall 212. The second tab 1212 is electrically connected to the end wall 211 through the second current collecting member 60, the end cap 22, and the side wall 212. Optionally, the end cap 22 is welded to the side wall 212.

[0426] In other examples, the second current collecting member 60 is connected to the side wall 212. The second tab 1212 is electrically connected to the end wall 211 through the second current collecting member 60 and the side wall 212. Optionally, the end cap 22 is insulated from the side wall 212.

[0427] In some embodiments, the height of the outer shell 20 is 1.3 to 4 times the diameter of the outer shell 20.

[0428] Exemplarily, the height of the outer shell 20 can be the dimension of the outer shell 20 along the axial direction Z.

[0429] Optionally, the height of the outer shell 20 is 1.3 times, 1.4 times, 1.5 times, 1.6 times, 1.7 times, 1.8 times, 1.9 times, 2.0 times, 2.1 times, 2.2 times, 2.3 times, 2.4 times, 2.5 times, 2.6 times, 2.7 times, 2.8 times, 2.9 times, 3.0 times, 3.1 times, 3.2 times, 3.3 times, 3.4 times, 3.5 times, 3.6 times, 3.7 times, 3.8 times, 3.9 times, or 4.0 times the diameter of the outer shell 20.

[0430] When the outer shell 20 satisfies the above size requirements, the structural stability of the outer shell 20 is relatively high, and the use reliability of the cylindrical battery cell 7 can be improved.

[0431] In some embodiments, the height of the outer shell 20 is 1.5 to 2.5 times the diameter of the outer shell 20.

[0432] In some embodiments, the height of the outer shell 20 is 50 mm to 150 mm. For example, the height of the outer shell 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.

[0433] Optionally, the height of the outer shell 20 is 60 mm-100 mm.

[0434] The outer shell 20 has a relatively large height to improve the capacity of the cylindrical battery cell 7.

[0435] In some embodiments, the diameter of the shell 20 is 45mm to 80mm. For example, the diameter of the shell 20 is 45mm, 50mm, 55mm, 60mm, 65mm, 70mm, 75mm or 80mm.

[0436] Optionally, the diameter of the shell 20 is 45mm to 60mm.

[0437] The shell 20 has a large diameter to improve the capacity of the cylindrical battery cell 7.

[0438] FIG. 26 is a schematic view of a partial cross-section of a cylindrical battery cell according to some embodiments of the present application.

[0439] Referring to FIG. 26, in some embodiments, the side wall 212 is provided with a protrusion 2121 protruding inwardly. In the axial direction Z, at least part of the protrusion 2121 is located between the end cover 22 and the second tab 1212.

[0440] Exemplarily, the protrusion 2121 can be a solid structure or a hollow structure.

[0441] The protrusion 2121 overlaps with the second tab 1212 in the axial direction Z, which can limit the movement of the second tab 1212 in the axial direction Z when the cylindrical battery cell 7 is subjected to external impact, and reduce the risk of disconnection between the second tab 1212 and the second current collecting member 60.

[0442] In some embodiments, the second current collecting member 60 is connected to the protrusion 2121. Exemplarily, the second current collecting member 60 can be welded to the protrusion 2121; alternatively, the second current collecting member 60 can also be crimped to the protrusion 2121.

[0443] Exemplarily, the second current collecting member 60 is connected to the side of the protrusion 2121 facing the second tab 1212, or to the side of the protrusion 2121 facing the end cover 22.

[0444] Connecting the second current collecting member 60 to the protrusion 2121 can shorten the conductive path between the second tab 1212 and the end wall 211, reduce the resistance, reduce the heat generation, and improve the cycle performance of the cylindrical battery cell 7.

[0445] In some embodiments, part of the second current collecting member 60 is located on the side of the protrusion 2121 facing the end cover 22 and connected to the protrusion 2121. Connecting the second current collecting member 60 to the outside of the protrusion 2121 can reduce the assembly difficulty.

[0446] In some embodiments, the second current collecting member 60 is welded to the protrusion 2121.

[0447] In some embodiments, the outer side of the side wall 212 is provided with a recess 2123 corresponding to the position of the protrusion 2121. As an example, after the electrode assembly is installed into the shell, the protrusion 2121 is formed by extruding the side wall 212 from the outer side.

[0448] In some embodiments, the side wall 212 further comprises a crimping portion 2122 extending from the protrusion 2121 away from one end of the end wall and arranged around the end cover 22.

[0449] Part of the crimping portion 2122 is bent and arranged to form a flange structure, and part of the end cover 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 cover 22 to achieve the fixation of the end cover 22 in the axial direction Z.

[0450] In some embodiments, the cylindrical battery cell 7 further comprises an insulating member 70 arranged between the side wall 212 and the end cover 22 and insulating the end cover 22 from the side wall 212.

[0451] In some embodiments, part of the insulating member 70 is located between the second current collecting member 60 and the end cover 22 to insulate the second current collecting member 60 from the end cover 22.

[0452] According to some embodiments of the present application, the present application also provides a battery comprising a plurality of cylindrical battery cells 7 of any of the above embodiments.

[0453] According to some embodiments of the present application, the present application also provides an electric device comprising a cylindrical battery cell 7 of any of the above embodiments, the cylindrical battery cell 7 being configured to provide electric energy for the electric device. The electric device can be any of the devices or systems mentioned above.

[0454] Referring to FIGS. 4-12, the present application provides a cylindrical battery cell 7 having a capacity greater than or equal to 20 Ah. The cylindrical battery cell 7 comprises a shell 20, an electrode assembly 10, an electrode terminal 30, a first current collecting member 40, and a second current collecting member 60.

[0455] The shell 20 comprises a shell body 21 and an end cover 22, the shell body 21 comprising an integrally formed side wall 212 and an end wall 211, the end wall 211 and the end cover 22 being opposite along an axial direction Z of the cylindrical battery cell 7, and the end cover 22 being welded to the side wall 212.

[0456] The electrode terminal 30 is arranged insulatively on the end wall 211. The electrode assembly 10 is accommodated in the shell 20.

[0457] The electrode assembly 10 includes first and second polar tabs 11 and 12 of opposite polarity and a separator 13 for separating the first and second polar tabs 11 and 12. The first polar tab 11, the separator 13, and the second polar tab 12 are wound in a winding direction V.

[0458] The first polar tab 11 includes a first current collector 111 and a first film layer 112, the first current collector 111 including a first coated region 1111 and a first tab 1112, the surface of the first coated region 1111 being coated with the first film layer 112, the first tab 1112 extending from the first coated region 1111 in one end of the axial direction Z of the cylindrical battery cell 7, and the surface of the first tab 1112 being uncoated with the first film layer 112.

[0459] The second polar tab 12 includes a second current collector 121 and a second film layer 122, the second current collector 121 including a second coated region 1211 and a second tab 1212, the surface of the second coated region 1211 being coated with the second film layer 122, the second tab 1212 extending from the second coated region 1211 in one end of the axial direction Z of the cylindrical battery cell 7, and the surface of the second tab 1212 being uncoated with the second film layer 122.

[0460] The first and second tabs 1112 and 1212 are located at both ends of the electrode assembly 10 in the axial direction Z, respectively. The first current collecting member 40 is welded to the electrode terminal 30 and the first tab 1112, respectively, and the second current collecting member 60 is welded to the second tab 1212 and electrically connected to the end wall 211.

[0461] In the winding direction V, the length of the connection position of the first tab 1112 to the first coated region 1111 is L1, and the length of the first coated region 1111 is L0, 0.8≤L1 / L0≤1.

[0462] In the winding direction V, the length of the connection position of the second tab 1212 to the second coated region 1211 is L4, and the length of the second coated region 1211 is L3, 0.8≤L4 / L3≤1.

[0463] 4500mm≤L0≤7000mm, 4500mm≤L3≤7000mm.

[0464] Embodiments

[0465] The following examples describe the present application in more detail, which are only used for illustrative purposes, because various modifications and changes within the scope of the present application are obvious to those skilled in the art. Unless otherwise stated, all parts, percentages and ratios reported in the following examples are based on mass, and all reagents used in the examples are commercially available or synthesized according to conventional methods and used directly without further purification, and the instruments used in the examples are commercially available.

[0466] Example 1

[0467] 1. Preparation of positive electrode sheet

[0468] The positive electrode sheet comprises a positive electrode current collector and a positive electrode film layer, the positive electrode film layer is located on both sides of the positive electrode current collector, the positive electrode current collector is an aluminum foil, and the positive electrode film layer is a film layer formed by uniformly coating a positive electrode slurry (the solvent is N-methyl pyrrolidone NMP) on the surface of the positive electrode current collector aluminum foil, and then drying and cold pressing. The positive electrode film layer comprises positive electrode active material, conductive agent carbon black (Super P) and binder polyvinylidene fluoride (PVDF) at a weight ratio of 97:1:2.

[0469] The positive electrode active material comprises a layered transition metal oxide with a molecular formula of LiNi 0.9 Co 0.05 Mn 0.05 O2.

[0470] The positive electrode current collector comprises a positive electrode coating area coated with the positive electrode film layer and a positive electrode tab without the positive electrode film layer. The length LX0 of the positive electrode coating area is 5100 mm, and the length LX1 of the connection position of the positive electrode tab and the positive electrode coating area is 5100 mm.

[0471] 2. Preparation of negative electrode sheet

[0472] The negative electrode sheet comprises a negative electrode current collector and a negative electrode film layer, the negative electrode film layer is located on both sides of the negative electrode current collector, the negative electrode current collector is a copper foil, and the negative electrode film layer is a film layer formed by uniformly coating a negative electrode slurry (the solvent is deionized water) on the surface of the negative electrode current collector copper foil, and then drying and cold pressing. The negative electrode film layer comprises silicon-based material (specifically silicon carbide), graphite, conductive agent carbon black, conductive agent carbon nanotube and binder polyacrylic acid at a weight ratio of 4.6:90.4:1.9:0.1:3.

[0473] The negative electrode current collector comprises a negative electrode coating area coated with the negative electrode film layer and a negative electrode tab without the negative electrode film layer. The length LX3 of the negative electrode coating area is 5250 mm, and the length LX4 of the connection position of the negative electrode tab and the negative electrode coating area is 5250 mm.

[0474] 3. Preparation of separator

[0475] A PE (polyethylene) base film is provided, and the thickness of the base film is 7 μm.

[0476] 4. Preparation of electrolyte

[0477] The electrolyte comprises an organic solvent and a lithium salt. The organic solvent is obtained by mixing ethylene carbonate (EC), methyl ethyl carbonate (EMC) and diethyl carbonate (DEC) in a volume ratio of 1:1:1, and then dissolving the lithium salt LiPF6, which is fully dried, in the mixed organic solvent to prepare an electrolyte with a lithium salt concentration of 1 mol / L.

[0478] 5. Preparation of cylindrical battery cell

[0479] The above positive electrode sheet, separator and negative electrode sheet are stacked in order with the separator between the positive electrode sheet and the negative electrode sheet to play a separating role, and the positive electrode sheet, separator and negative electrode sheet are wound to obtain an electrode assembly. The positive tab and the negative tab are subjected to rubbing and flattening treatment. The electrode assembly is placed in a cylindrical outer shell, and after drying, the electrolyte is injected. After vacuum packaging, standing, formation and shaping, a cylindrical battery cell is obtained.

[0480] The electrode assembly has a cylindrical structure, and the outer shell has a cylindrical structure. The diameter of the cylindrical battery cell is 46 mm, and the height is 95 mm.

[0481] Example 2

[0482] The battery cell is prepared by using a method similar to that of Example 1, except that the length of the connection position of the positive tab and the positive coating area is adjusted to 4845 mm.

[0483] Example 3

[0484] The battery cell is prepared by using a method similar to that of Example 1, except that the length of the connection position of the positive tab and the positive coating area is adjusted to 4080 mm.

[0485] Example 4

[0486] The battery cell is prepared by using a method similar to that of Example 1, except that the length of the connection position of the negative tab and the negative coating area is adjusted to 4200 mm.

[0487] Example 5

[0488] The battery cell is prepared by using a method similar to that of Example 1, except that the length of the connection position of the positive tab and the positive coating area is adjusted to 4080 mm, and the length of the connection position of the negative tab and the negative coating area is adjusted to 4200 mm.

[0489] Example 6

[0490] A battery cell was prepared in a similar manner to Example 1, except that the length of the connection position between the positive tab and the positive coating area was adjusted to 3570 mm, and the length of the connection position between the negative tab and the negative coating area was adjusted to 4200 mm.

[0491] Example 7

[0492] A battery cell was prepared in a similar manner to Example 1, except that the length of the connection position between the positive tab and the positive coating area was adjusted to 4080 mm, and the length of the connection position between the negative tab and the negative coating area was adjusted to 3675 mm.

[0493] Comparative Example 1

[0494] A battery cell was prepared in a similar manner to Example 1, except that the length of the connection position between the positive tab and the positive coating area was adjusted to 3060 mm, and the length of the connection position between the negative tab and the negative coating area was adjusted to 3150 mm.

[0495] Performance test

[0496] 1. First week discharge capacity test

[0497] The cylindrical battery cell of each example and comparative example was tested in the following manner, respectively.

[0498] Fresh cylindrical battery cell was charged to 4.25 V at 0.33 C constant current at 25 °C, and then continued to charge at 4.25 V constant voltage until the charge current decayed to 0.05 C, and then rested for 30 min. Then it was discharged to 2.5 V at 0.33 C constant current, and the first week discharge capacity was recorded, in Ah.

[0499] 2. Cycle test of cylindrical battery cell

[0500] The cylindrical battery cell of each example and comparative example was tested in the following manner, respectively.

[0501] Fresh cylindrical battery cell was charged to 4.25 V at 0.33 C constant current at 25 °C, and then continued to charge at 4.25 V constant voltage until the charge current decayed to 0.05 C, and then rested for 30 min. Then it was discharged to 2.5 V at 0.33 C constant current, and the first week discharge capacity was recorded, in Ah.

[0502] 3. Lithium precipitation area test of cylindrical battery cell

[0503] The cylindrical battery cell of each example and comparative example was tested in the following manner, respectively.

[0504] After the cylindrical battery monomer is cycled for 50 cycles according to the following charge and discharge strategy, it is fully charged to 100% SOC according to the corresponding charging strategy, the negative plate in the cylindrical battery monomer is disassembled, the negative plate is unfolded, the precipitation area (gray-white area) is observed, and the precipitation area is measured, and the precipitation degree is as follows:

[0505] No lithium precipitation: lithium precipitation area <0.05%.

[0506] Mild lithium precipitation: lithium precipitation area <2%.

[0507] Severe lithium precipitation: lithium precipitation area >2%.

[0508] Charge the cylindrical battery monomer at an external environment temperature of 30°C, and the charging steps include the following steps:

[0509] Charge from 0% SOC to 30% SOC at a constant current of 3.0C;

[0510] Charge from 30% SOC to 35% SOC at a constant current of 2.8C;

[0511] Charge from 35% SOC to 40% SOC at a constant current of 2.6C;

[0512] Charge from 40% SOC to 45% SOC at a constant current of 2.4C;

[0513] Charge from 45% SOC to 50% SOC at a constant current of 2.2C;

[0514] Charge from 50% SOC to 55% SOC at a constant current of 2.0C;

[0515] Charge from 55% SOC to 60% SOC at a constant current of 1.8C;

[0516] Charge from 60% SOC to 65% SOC at a constant current of 1.6C;

[0517] Charge from 65% SOC to 70% SOC at a constant current of 1.4C;

[0518] Charge from 70% SOC to 75% SOC at a constant current of 1.3C;

[0519] Charge from 75% SOC to 80% SOC at a constant current of 1.2C;

[0520] Charge from 80% SOC to 85% SOC at a constant current of 0.8C;

[0521] Charge from 85% SOC to 90% SOC at a constant current of 0.6C;

[0522] Charge from 90% SOC to 95% SOC at a constant current of 0.4C;

[0523] Charged from 95% SOC to 98% SOC at 0.33C constant current;

[0524] Charged from 98% SOC to 100% SOC at 0.3C constant current.

[0525] The cut-off voltage of the last charging step in the above charging steps is 4.25V.

[0526] The discharge strategy is as follows: discharged to the cut-off voltage 2.5V at 0.33C constant current.

[0527] 4. DCR test of cylindrical battery cell

[0528] The method can be referred to in GB / T 31467 "Performance test specification of high power lithium ion traction battery for HEV".

[0529] For example, at 25℃, the cylindrical battery cell is charged to 4.25V at 0.33C constant current, and then continues to be charged at 4.25V constant voltage until the charging current decays to 0.05C, and then stands for 30min; then discharged to 2.5V at 0.33C constant current, and records the discharge capacity A0, unit Ah; then, the cylindrical battery cell is charged to 4.25V at 0.33C constant current, and then continues to be charged at 0.05C, and stands for 30min; then discharged at 0.33C constant current to 0.5A0, so that the cylindrical battery cell is at 50% SOC.

[0530] After the battery cell is placed at 25℃ for 2h, it is discharged at a current of 2C for 10s, and the ΔU discharge and ΔI discharge are recorded, and the discharge DCR data of the cylindrical battery cell is calculated by the following formula.

[0531] Rdischarge=ΔUdischarge / ΔIdischarge,

[0532] Wherein, ΔUdischarge represents the voltage change within 10s of the start of discharge, and ΔIdischarge represents the current value within 10s of the start of discharge.

[0533] It is stated in this specification that each example and each comparative example can prepare four identical cylindrical battery cells, and four tests are respectively carried out.

[0534] The test results are shown in Table 1.

[0535] Table 1

[0536] Referring to Examples 1-5, 7 and Comparative Example 1, limiting LX1 / LX0 to 0.8-1 can increase the overcurrent area of the connection position of the positive electrode coating area and the positive electrode tab, reduce the direct current resistance, reduce the risk of lithium precipitation, improve the cycle performance of the cylindrical battery cell, reduce the risk of thermal runaway, and improve the reliability of the cylindrical battery cell.

[0537] With reference to the examples 1-6 and the comparative example 1, the LX4 / LX3 is limited to 0.8-1, the overcurrent area of the negative electrode coating area and the connection position of the negative electrode tab can be increased, the direct current resistance can be reduced, the risk of lithium precipitation can be reduced, the cycle performance of the cylindrical battery cell can be improved, the risk of thermal runaway can be reduced, and the reliability of the cylindrical battery cell can be improved.

[0538] With reference to the examples 1-5 and the comparative example 1, the LX1 / LX0 is limited to 0.8-1 and the LX4 / LX3 is limited to 0.8-1, the direct current resistance can be further reduced, the risk of lithium precipitation can be reduced, the cycle performance of the cylindrical battery cell can be improved, the risk of thermal runaway can be reduced, and the reliability of the cylindrical battery cell can be improved.

[0539] With reference to the examples 1-7, the cylindrical battery cell is less likely to have lithium precipitation or has a relatively mild lithium precipitation during fast charging. The cylindrical battery cell of the present application has good fast charging capability.

[0540] It should be noted that the examples in the present application and the features in the examples can be combined with each other without conflict.

[0541] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacement for part of the technical features, but these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the examples of the present application.

Claims

1. A cylindrical battery cell, wherein, The cylindrical battery cell has a capacity greater than or equal to 20 Ah, and includes a housing and an electrode assembly accommodated in the housing; The electrode assembly includes first and second polar plates of opposite polarity, the first and second polar plates being wound in a winding direction, the first polar plate including a first current collector and a first film layer, the first current collector including a first coated region and a first tab, a surface of the first coated region being coated with the first film layer, the first tab extending from one end of the first coated region in an axial direction of the cylindrical battery cell, and a surface of the first tab being uncoated with the first film layer; The cylindrical battery cell includes a first electrode lead-out portion, and the first tab is electrically connected to the first electrode lead-out portion; In the winding direction, a length of a connection position of the first tab and the first coated region is L1, a length of the first coated region is L0, and 0.8≤L1 / L0≤1.

2. The cylindrical battery cell of claim 1, wherein, 0.95≤L1 / L0≤1.

3. The cylindrical battery cell according to claim 1 or 2, wherein, 3000mm≤L0≤9000mm.

4. The cylindrical battery cell of any one of claims 1-3, wherein, 2400mm≤L1≤9000mm.

5. The cylindrical battery cell of any one of claims 1-4, wherein, The first tab has a thickness equal to that of the first coated region.

6. The cylindrical battery cell of any one of claims 1-5, wherein, A sum of a thickness of the first film layer and a thickness of the first coated region is D1, the thickness of the first coated region is T1, and 0.17≤T1 / D1≤0.

35.

7. The cylindrical battery cell of claim 6, wherein, 9μm≤T1≤17μm.

8. The cylindrical battery cell of any one of claims 1-7, wherein, A sum of a thickness of the first film layer and a thickness of the first coated region is D1, the thickness of the first film layer is T2, and 0.67≤T2 / D1≤0.

81.

9. The cylindrical battery cell of any one of claims 1-8, wherein, The cylindrical battery cell has a capacity of 25 Ah-50 Ah.

10. The cylindrical battery cell of any one of claims 1-9, wherein, The connection position of the first tab and the first coated region is continuously provided in the winding direction.

11. The cylindrical battery cell of claim 10, wherein, The first tab is continuously provided in the winding direction as a whole.

12. The cylindrical battery cell of claim 10, wherein, The first tab includes a transition portion and a plurality of first sub-tabs spaced apart in the winding direction, the transition portion being connected to the first coated region, the first sub-tabs being connected to one end of the transition portion away from the first coated region, and a connection position of the transition portion and the first coated region being continuously provided in the winding direction.

13. The cylindrical battery cell of claim 12, wherein, In the winding direction, a sum of lengths of connection positions of the plurality of first sub-tabs and the transition portion is L2, and a length of the connection position of the transition portion and the first coated region is L1. L2 and L1 satisfy: 0.6≤L2 / L1≤0.

95.

14. The cylindrical battery cell of any one of claims 1-13, wherein, One end of the first tab away from the first coated region is bent and forms a first layer stack portion, the first layer stack portion has a multi-layer structure in an axial direction of the cylindrical battery cell, and the first layer stack portion is electrically connected to the first electrode lead-out portion.

15. The cylindrical battery cell according to claim 14, comprising a first current collection member at least partially located between the first layer stack portion and the first electrode lead-out portion, the first current collection member being welded to the first layer stack portion and the first electrode lead-out portion, respectively.

16. The cylindrical battery cell of any one of claims 1-15, wherein, The first electrode lead-out portion includes an electrode terminal insulatively provided to the housing, at least a portion of the electrode terminal protruding from a wall portion of the housing, and the first tab is electrically connected to the electrode terminal.

17. The cylindrical battery cell of claim 16, wherein, The thermal conductivity of the electrode terminal is greater than the thermal conductivity of the shell.

18. The cylindrical battery cell of any one of claims 1-17, wherein, The first pole piece is a positive pole piece, and the material of the first current collector is aluminum or an aluminum alloy.

19. The cylindrical battery cell of any one of claims 1-18, wherein, The second pole piece comprises a second current collector and a second film layer, the second current collector comprises a second coated area and a second tab, the surface of the second coated area is coated with the second film layer, the second tab extends from one end of the second coated area along the axial direction, and the surface of the second tab is not coated with the second film layer. In the axial direction, the first tab and the second tab are respectively located at two ends of the electrode assembly; the cylindrical battery monomer comprises a second electrode lead-out part, and the second tab is electrically connected to the second electrode lead-out part.

20. The cylindrical battery cell of claim 19, wherein, In the winding direction, the length of the second coated area is L3, and the length of the connection position of the second tab and the second coated area is L4. 0.8≤L4 / L3≤1.

21. The cylindrical battery cell of claim 19 or 20, wherein, The first pole piece is a positive pole piece, and the second pole piece is a negative pole piece. The material of the first current collector is aluminum, and the material of the second current collector is copper.

22. The cylindrical battery cell of claim 21, wherein, The thickness of the first coated area is greater than the thickness of the second coated area, and the thickness of the first tab is greater than the thickness of the second tab.

23. The cylindrical battery cell of any one of claims 1-22, wherein, The electrode assembly further comprises a separator, the separator is wound along the winding direction, and the first pole piece and the second pole piece are separated by the separator. The separator comprises a base and a plurality of support portions, the base has two first surfaces oppositely arranged along the thickness direction of the base, and the plurality of support portions are protruded from at least one of the first surfaces to form a gap between the first pole piece and the second pole piece.

24. The cylindrical battery cell of claim 23, wherein, The plurality of support portions comprise a first support portion and a second support portion, 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.

25. The cylindrical battery cell of claim 23 or 24, wherein, The support portion comprises organic particles arranged on the base.

26. The cylindrical battery cell of claim 25, wherein, The base comprises a base film and an inorganic particle layer arranged on the base film, and the organic particles at least partially protrude from the inorganic particle layer.

27. The cylindrical battery cell of claim 25 or 26, wherein, The plurality of organic particles comprise first organic particles and second organic particles, and the number average particle size of the first organic particles is greater than the number average particle size of the second organic particles.

28. The cylindrical battery cell of any one of claims 25-27, wherein, The plurality of support portions comprise a first support portion and a second support portion, the height of the first support portion protruding from the first surface is greater than the height of the second support portion protruding from the first surface. The plurality of organic particles comprise first organic particles and second organic particles; the first support portion comprises the first organic particles, and the second support portion comprises the second organic particles.

29. The cylindrical battery cell of any one of claims 23-28, wherein, The radial dimension of at least part of the gap is 5-60 μm.

30. The cylindrical battery cell of any one of claims 23-29, wherein, Both sides of the separator are provided with a plurality of support portions. The gap comprises a first gap and a second gap, the first gap is formed between the first pole piece and the separator, and the second gap is formed between the second pole piece and the separator.

31. The cylindrical battery cell of any one of claims 23-30, wherein, The gap extends along the winding direction, and the gap has a winding starting end and a winding ending end. The radial dimension of the part of the gap close to the winding starting end is greater than or equal to the radial dimension of the part of the gap close to the winding ending end.

32. The cylindrical battery cell of any one of claims 23-31, wherein, A radial dimension of at least part of the gap gradually decreases along the winding direction.

33. The cylindrical battery cell of any one of claims 23-32, wherein, The gap comprises a middle region and two end regions arranged along the axial direction, the middle region being located between the two end regions, and a radial dimension of the middle region is smaller than that of the end regions.

34. The cylindrical battery cell of claim 33, wherein, A radial dimension of the gap gradually decreases in a direction from the end region to the middle region.

35. The cylindrical battery cell of any one of claims 23-34, wherein, In a radial direction of the cylindrical battery cell, a part of the plurality of support portions is located between the first tab and the base.

36. The cylindrical battery cell of any one of claims 1-35, wherein, The shell has a melting point greater than or equal to 1050°C; and / or The shell has a tensile strength greater than or equal to 300 MPa.

37. The cylindrical battery cell of any one of claims 1-36, wherein, The shell is a steel shell.

38. The cylindrical battery cell of any one of claims 1-37, wherein, The shell comprises a shell body and an end cover, the shell body comprising an integrally formed side wall and an end wall, the side wall surrounding the electrode assembly, the end wall and the end cover being opposite along an axial direction of the cylindrical battery cell, and the end cover being sealingly connected to the side wall.

39. The cylindrical battery cell of claim 38, wherein, The second tab comprises a second tab; The first electrode lead-out portion comprises an electrode terminal insulatively provided on the end wall, the first tab being electrically connected to the electrode terminal, and the second tab being electrically connected to the end wall.

40. The cylindrical battery cell of claim 39, wherein, The cylindrical battery cell further comprises a first current collecting member, the first current collecting member being located on a side of the first tab facing the end wall and connected to the first tab. The electrode terminal abuts against and is connected to a surface of the first current collecting member facing the end wall.

41. The cylindrical battery cell of claim 40, wherein, The electrode terminal is provided with a terminal recess on a side facing the first current collecting member, and / or the electrode terminal is provided with a terminal recess on a side facing away from the first current collecting member. A bottom wall of the terminal recess is welded to the first current collecting member.

42. The cylindrical battery cell of any one of claims 39-41, wherein, The first tab is located at an end of the first tab facing the end wall, and the second tab is located at an end of the second tab facing the end cover. The cylindrical battery cell further comprises a second current collecting member connected to the second tab; and the second current collecting member is connected to at least one of the end cover and the side wall.

43. The cylindrical battery cell of claim 42, wherein, The side wall is provided with a protrusion protruding inwardly, at least part of the protrusion being located between the end cover and the second tab in the axial direction. The second current collecting member is connected to the protrusion.

44. The cylindrical battery cell of claim 43, wherein, A part of the second current collecting member is located on a side of the protrusion facing the end cover and connected to the protrusion.

45. The cylindrical battery cell of any one of claims 1-44, wherein, A height of the shell is 1.3 to 4 times a diameter of the shell.

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

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

48. An electrical device comprising the battery according to claim 47, the battery being configured to provide electrical energy.

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