Cylindrical battery cell, battery device and power utilization device

Abstract

The utility model belongs to the technical field of batteries, and particularly relates to a cylindrical battery monomer, a battery device and a power utilization device.The cylindrical battery monomer comprises a shell and an electrode assembly, and the diameter of the shell is larger than or equal to 40 mm; the electrode assembly is of a winding structure, is accommodated in the shell and comprises a separator, a first pole piece and a second pole piece, and the first pole piece and the second pole piece are opposite in polarity; the first pole piece comprises a first current collector and a first active material layer, and the surface of the first current collector is connected with the first active material layer; the second pole piece comprises a second current collector and a second active material layer, and the second current collector is connected with the second active material layer; m gap winding rings are formed between the first active material layer and the second active material layer, m is greater than or equal to 30, and m is a natural number; the gap winding ring on the innermost side is the first gap winding ring; the average value of the radial dimensions of the (m-13)-(m-5)-th gap winding turns is greater than the average value of the radial dimensions of the (5th)-13th gap winding turns.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of batteries, and particularly relates to a cylindrical battery monomer, a battery device and a power utilization device. BACKGROUND

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

[0003] With the increase of energy density, the diameter of the cylindrical battery monomer is continuously increased; in particular, the cylindrical battery monomer with a diameter greater than or equal to 40 mm has a large expansion force in the cycle process, and the large expansion force will affect the use reliability of the cylindrical battery monomer. How to better balance the use reliability and the energy density of the cylindrical battery monomer is an important research direction in the technical field of batteries.

[0004] The above statements are only used to provide background technical information related to the application, and do not necessarily constitute the prior art. CONTENT OF THE UTILITY MODEL

[0005] The purpose of the embodiments of the application is to provide a cylindrical battery monomer, a battery device and a power utilization device, which can better balance the use reliability and the energy density of the cylindrical battery monomer.

[0006] The technical solution adopted by the embodiments of the application is:

[0007] In a first aspect, a cylindrical battery monomer is provided, comprising a shell and an electrode assembly, the diameter of the shell being greater than or equal to 40 mm; the electrode assembly is in a wound structure, at least part of the electrode assembly being accommodated in the shell, the electrode assembly comprising a separator and first and second electrode sheets with opposite polarities, at least part of the separator being located between the first and second electrode sheets; the first electrode sheet comprises a first current collector and a first active material layer, the first active material layer being connected to at least part of an area of at least one surface of the first current collector along the thickness direction of the first current collector, at least part of the first active material layer being located between the first current collector and the separator; the second electrode sheet comprises a second current collector and a second active material layer, the second active material layer being connected to at least part of an area of at least one surface of the second current collector along the thickness direction of the second current collector, at least part of the second active material layer being located between the second current collector and the separator, and m gaps are formed between the first and second active material layers, m being a natural number greater than or equal to 30; the innermost one of the gap winding turns is the first gap winding turn; the average value of the radial dimensions of the m-13th to m-5th gap winding turns is greater than the average value of the radial dimensions of the 5th to 13th gap winding turns.

[0008] By adopting the technical scheme of the embodiment, in the cycle process of the cylindrical battery monomer, the expansion of the electrode assembly gradually accumulates from inside to outside along the radial direction, and the expansion accumulation force of the outside of the electrode assembly is large; the m-13th to m-5th gap winding turns are arranged outside compared with the 5th to 13th gap winding turns, and the average value of the radial dimension of the m-13th to m-5th gap winding turns is larger than the average value of the radial dimension of the 5th to 9th gap winding turns, so that the gap winding turns outside the electrode assembly have a larger radial dimension, which can provide more expansion space for the outside of the electrode assembly, absorb the accumulated expansion amount of the electrode assembly, and effectively reduce the acting force between the electrode assembly and the shell, reduce the deformation amount of the shell, reduce the risk of cracking of the shell, and improve the reliability of the cylindrical battery monomer; in addition, the gap winding turns outside the electrode assembly have a larger radial dimension, which is also beneficial to reducing the electrolyte extrusion amount outside the electrode assembly, and is beneficial to improving the cycle performance of the cylindrical battery monomer; the average value of the radial dimension of the 5th to 9th gap winding turns is small, so that the gap winding turns inside the electrode assembly have a larger radial dimension, which can increase the compactness of the structure inside the electrode assembly, and is beneficial to improving the energy density of the cylindrical battery monomer. Therefore, the cylindrical battery monomer can better balance the use reliability and the energy density.

[0009] In some embodiments, the gap winding turns include a first gap sub-turn and a second gap sub-turn, the first gap sub-turn is located between the first active material layer and the separator, and the second gap sub-turn is located between the second active material layer and the separator.

[0010] By adopting the technical scheme of the embodiment, the first gap sub-turn and the second gap sub-turn can both provide space for the expansion of the electrode assembly, thereby reducing the extrusion effect on the shell, reducing the risk of deformation and cracking of the shell, and improving the reliability of the cylindrical battery monomer.

[0011] In some embodiments, the radial dimension of the first gap winding turn is smaller than the radial dimension of the mth gap winding turn.

[0012] By adopting the technical scheme of the embodiment, the radial dimension of the mth gap winding turn is large, which can provide more expansion space for the electrode assembly, absorb the accumulated expansion amount of the electrode assembly, and thereby reduce the acting force between the electrode assembly and the shell, reduce the deformation amount of the shell, reduce the risk of cracking of the shell, and improve the reliability.

[0013] In some embodiments, the m gap winding turns are divided into j groups of gap winding turns in sequence from the inside to the outside of the electrode assembly; the innermost group of gap winding turns is the first group of gap winding turns, and each group of gap winding turns from the first group to the (j-1)th group includes 9 gap winding turns, 1≤m-9*(j-1)≤9, and j is a natural number; the average value of the radial dimensions of the first group to the (j-1)th group of gap winding turns is arranged in an increasing manner.

[0014] By adopting the technical solutions of this embodiment, the average value of the radial dimensions of the first group to the (j-1)th group of gap winding turns is arranged in an increasing manner, the radial dimensions of the gap winding turns increase from the inside to the outside of the electrode assembly, the radial dimensions of the gap winding turns on the outside of the electrode assembly are large, which can provide more expansion space for the electrode assembly, absorb the accumulated expansion amount of the electrode assembly, and thus reduce the acting force between the electrode assembly and the shell, reduce the deformation amount of the shell, reduce the risk of cracking of the shell, and improve the reliability. In addition, the radial dimensions of the gap winding turns on the outside of the electrode assembly are small, which can effectively increase the compactness of the structure on the inside of the electrode assembly, and is conducive to improving the energy density of the cylindrical battery cell.

[0015] In some embodiments, the first tab winding is arranged to form a plurality of first tab winding turns, the first current collector includes a first current winding turn located at the first tab winding turn, the first active material layer includes a first active winding turn located at the first tab winding turn, and the first active winding turn has a first winding surface facing away from the corresponding first current winding turn; the first winding surface of at least one first tab winding turn is provided with a groove.

[0016] By adopting the technical solutions of this embodiment, in the charging and discharging process of the battery cell, ions pass through the separator and travel back and forth between the second tab and the first active winding turn of the first tab winding turn through the electrolyte, thereby realizing the transmission of electrical energy of the cylindrical battery cell. At the same time, in the charging and discharging process of the battery cell, the electrode assembly expands, the distance between the second tab and the first winding surface of the first tab winding turn decreases, and the electrolyte between the second tab and the first winding surface is squeezed out. The first winding surface of at least one first tab winding turn is provided with at least one groove. On the one hand, the electrolyte can flow into the groove for storage, the stored electrolyte can soak the first tab and provide a transmission path for ions, reduce the transmission resistance of ions, and improve the cycle performance of the cylindrical battery cell. On the other hand, the groove can also provide a channel for the backflow of the electrolyte, reduce the difficulty of the backflow of the electrolyte, reduce the transmission resistance of the ions, improve the soaking effect of the first tab, and also be conducive to improving the cycle performance of the cylindrical battery cell.

[0017] In some embodiments, the number of grooves is a plurality, and the plurality of grooves includes at least one first groove formed along the axial direction of the cylindrical battery cell, and the first groove extends along the axial direction of the cylindrical battery cell.

[0018] By adopting the technical scheme of the embodiment, in the cylindrical battery monomer, the electrode assembly expands, the electrolyte is squeezed out from the electrode assembly along the two ends of the axial direction of the cylindrical battery monomer, the first groove is formed along the axial direction of the cylindrical battery monomer, the electrolyte squeezed out by the electrode assembly can be better guided to flow back, the flow back rate of the electrolyte is effectively improved, the impregnation effect of the first pole piece is improved, and the cycle performance of the cylindrical battery monomer is improved.

[0019] In some embodiments, the number of the first grooves is multiple, the multiple first grooves are arranged at intervals along the winding direction of the electrode assembly, and the distance between the two adjacent first grooves is arranged in an increasing manner.

[0020] By adopting the technical scheme of the embodiment, after the first pole piece is wound along the winding direction of the electrode assembly, the number of the first grooves close to the inner side of the electrode assembly is more, and the number of the first grooves close to the outer side of the electrode assembly is less, which is conducive to improving the electrolyte flow back effect of the inner side of the electrode assembly, improving the impregnation effect of the inner side of the electrode assembly, and effectively improving the cycle performance of the battery monomer.

[0021] In some embodiments, the thickness of the first active material layer is t, and the groove depth of the first groove is h, where 0.05≤h / t≤0.84, and optionally, 0.08≤h / t≤0.8; and optionally, 0.1≤h / t≤0.5.

[0022] By adopting the technical scheme of the embodiment, the first groove can store electrolyte and guide the electrolyte to flow back, improve the impregnation effect of the first pole piece, and improve the cycle performance of the cylindrical battery monomer; the first groove does not penetrate the first active material layer, and the first current collector is not exposed, thereby reducing the risk of direct reaction of the first current collector with ions. In addition, compared with the first groove penetrating the first active material layer, the first active material layer removes less active material by grooving, which is conducive to improving the active material capacity of the first pole piece and reducing the risk of degradation of the use performance of the cylindrical battery monomer due to insufficient active material capacity of the first pole piece. Therefore, the cycle performance and use performance of the cylindrical battery monomer can be considered.

[0023] In some embodiments, the groove depth of the first groove is h, and 0 μm < h ≤ 50 μm, and optionally, 6 μm ≤ h ≤ 30 μm.

[0024] By adopting the technical scheme of the embodiment, the groove depth of the first groove is reasonable, the first groove can store electrolyte and guide the electrolyte to flow back, improve the impregnation effect of the first pole piece, and improve the cycle performance of the cylindrical battery monomer; in addition, the first active material layer removes less active material by grooving, which is conducive to improving the active material capacity of the first pole piece and reducing the risk of degradation of the use performance of the cylindrical battery monomer due to insufficient active material capacity of the first pole piece. Therefore, the cycle performance and use performance of the cylindrical battery monomer can be considered.

[0025] In some embodiments, the first groove has a groove width w, where 30 pm≤w≤1000 pm; optionally, 50 pm≤w≤500 pm; optionally, 80 pm≤w≤120 pm.

[0026] By adopting the technical solutions of this embodiment, the first groove can store electrolyte and guide the electrolyte backflow, improve the wettability of the first electrode tab, improve the cycle performance of the cylindrical battery cell, and also facilitate the processing and manufacturing of the first groove; it can also reduce the loss of active material due to the groove removal of the first active material layer, which is conducive to improving the active material capacity of the first electrode tab, and can also reduce the risk of degradation of the use performance of the cylindrical battery cell due to insufficient active material capacity of the first electrode tab; in addition, the first groove is not easily flattened during the hot pressing process of the first electrode tab, and the shape of the first groove can be stably maintained. Therefore, the cycle performance and use performance of the cylindrical battery cell can be considered.

[0027] In some embodiments, the first groove has a groove width w, and the first groove has a groove depth h, where 0.05≤h / w≤1; optionally, 0.1≤h / w≤0.5.

[0028] By adopting the technical solutions of this embodiment, under the condition that h is constant, the groove width of the first groove is not too large, so that the first groove is not easily flattened during the hot pressing process of the first electrode tab, and the shape of the first groove can be stably maintained; it can also make the electrolyte have a relatively wide channel during the backflow process, which is conducive to the backflow of the electrolyte and improves the cycle performance of the cylindrical battery cell; therefore, the processing and manufacturing of the first groove and the cycle performance of the cylindrical battery cell can be considered.

[0029] In some embodiments, along the axial direction of the cylindrical battery cell, the size of the first active material layer is L, and the groove depth of the first groove is h, where 5*10 -5 ≤h / L≤5*10 -4 .

[0030] By adopting the technical solutions of this embodiment, under the condition that L is constant, the design of 5*10 -5 ≤h / L≤5*10 -4 can make the electrolyte backflow faster and improve the wettability of the first electrode tab; in addition, the design of 5*10 -4 ≤h / L≤5*10 -4 can reduce the risk of excessive loss of active material due to the excessive groove depth of the first groove and the exposure of the first current collector, so the cycle performance and use reliability of the cylindrical battery cell can be considered.

[0031] In some embodiments, along the axial direction of the cylindrical battery cell, the size of the first active material layer is L, and the groove depth of the first groove is h, where L≥60 mm and h≥6 pm.

[0032] By adopting the technical solutions of this embodiment, for a cylindrical battery monomer with L≥60mm, h≥6μm, the first groove can store more electrolyte and can better guide the electrolyte backflow, which can effectively improve the impregnation effect of the first pole piece and improve the cycle performance of the cylindrical battery monomer.

[0033] In some embodiments, along the axial direction of the cylindrical battery monomer, the size of the first groove is l, the size of the first active material layer is L, and 0.8≤l / L≤1; optionally, 0.9≤l / L≤0.98.

[0034] By adopting the technical solutions of this embodiment, along the axial direction of the cylindrical battery monomer, the size of the first groove and the size of the first active material layer are not much different or the same, and the two ends of the first groove are relatively close to the two ends of the first active material layer, so that the electrolyte squeezed out from the two ends of the electrode assembly can quickly backflow through the first groove, which can effectively improve the impregnation effect of the first pole piece and improve the cycle performance of the cylindrical battery monomer.

[0035] In some embodiments, 60mm≤L≤330mm, and optionally, 70mm≤L≤200mm.

[0036] By adopting the technical solutions of this embodiment, along the axial direction of the cylindrical battery monomer, the size of the first active material layer is large, and the first active material layer contains more active material, which improves the capacity of the cylindrical battery monomer; however, along the axial direction of the cylindrical battery monomer, the distance of the squeezed-out electrolyte backflowing to the middle part of the first active material layer is far, which increases the difficulty of the squeezed-out electrolyte backflowing to the middle part of the first active material layer, and in combination with the design of 0.8≤l / L≤1, the squeezed-out electrolyte can quickly backflow to the middle part of the first active material layer through the first groove, which is conducive to improving the impregnation effect of the first pole piece and improving the cycle performance of the cylindrical battery monomer, so that the capacity and cycle performance of the cylindrical battery monomer can be considered.

[0037] In some embodiments, the first groove comprises a first groove segment and a second groove segment connected in communication, the first groove segment is connected with the second groove segment at at least one end along the axial direction of the cylindrical battery monomer, the groove depth of the first groove segment is greater than the groove depth of the second groove segment, and / or the groove width of the first groove segment is greater than the groove width of the second groove segment.

[0038] By adopting the technical solutions of this embodiment, the size of the second groove segment is smaller than the size of the first groove segment, and the electrolyte is prone to produce a siphon effect at the second groove segment, which is conducive to the rapid backflow of the electrolyte, improves the impregnation effect of the first pole piece, and improves the cycle performance of the cylindrical battery monomer.

[0039] In some embodiments, the groove depth of the second groove section decreases from the first groove section in a direction pointing from the first groove section to the second groove section; and / or, the groove width of the second groove section decreases from the first groove section in a direction pointing from the first groove section to the second groove section.

[0040] By adopting the technical solutions of this embodiment, the size of the second groove section gradually decreases from the first groove section in a direction away from the first groove section, a pressure difference of electrolyte flow can be formed, the second groove section can produce a better siphon effect, the electrolyte can be more quickly sucked into the second groove section and quickly return to the first groove section through the second groove section, and the first wetting effect can be better improved, and the cycle performance of the cylindrical battery cell can be improved.

[0041] In some embodiments, the first groove includes a plurality of sub-sections, and the plurality of sub-sections are distributed at intervals along the axial direction of the cylindrical battery cell.

[0042] By adopting the technical solutions of this embodiment, the first groove includes a plurality of sub-sections, the amount of active material loss of the first electrode tab can be reduced by groove removal of the first active material layer, the use performance of the battery cell can be improved, in addition, the plurality of sub-sections are arranged at intervals, compared with the use of a whole-section first groove, the structural strength and rigidity of the first electrode tab can be improved, and the use reliability of the cylindrical battery cell can be improved.

[0043] In some embodiments, along the axial direction of the cylindrical battery cell, the interval between two adjacent sub-sections is d, and 0.1mm≤d≤1mm; optionally, 0.3mm≤d≤0.6mm.

[0044] By adopting the technical solutions of this embodiment, the design of d≥0.1mm makes the two adjacent sub-sections arranged at intervals, the amount of active material loss of the first electrode tab is reduced, and the use performance of the cylindrical battery cell is improved; the design of d≤1mm makes the electrolyte between the two adjacent sub-sections flow to each other, the distribution of the electrolyte is more uniform, and the cycle performance of the cylindrical battery cell can be improved.

[0045] In some embodiments, along the winding direction of the electrode assembly, in two adjacent first grooves, the sub-sections of one of the first grooves are arranged to be staggered with at least part of the sub-sections of the other first groove.

[0046] By adopting the technical solutions of this embodiment, the plurality of sub-sections of the two adjacent first grooves are staggered, the uniformity of the distribution of the electrolyte can be improved, the wetting effect of the first electrode tab can be improved, and the cycle performance of the cylindrical battery cell can be improved.

[0047] In some embodiments, the number of grooves is a plurality, the plurality of grooves form a plurality of groove groups, each groove group includes a plurality of intersecting grooves, and the plurality of groove groups are arranged at intervals along the winding direction of the electrode assembly.

[0048] By adopting the technical scheme of this embodiment, the plurality of grooves are divided into a plurality of groups, each group of grooves includes a plurality of intersecting grooves, and the electrolyte can flow in the plurality of grooves, which is conducive to improving the uniformity of electrolyte distribution, improving the wettability of the first electrode sheet, and improving the cycle performance of the cylindrical battery monomer. In addition, the plurality of groups of grooves are arranged at intervals along the winding direction of the electrode assembly, which can reduce the loss of active material of the first electrode sheet, is conducive to improving the capacity of the cylindrical battery monomer, and can also improve the structural strength and rigidity of the first electrode sheet, which is conducive to improving the use reliability of the cylindrical battery monomer.

[0049] In some embodiments, the number of the first electrode sheet winding turns is n, n≥30, n is a natural number, and the innermost one of the first electrode sheet winding turns is the first first electrode sheet winding turn. At least one of the first 10 first electrode sheet winding turns is provided with a groove.

[0050] By adopting the technical scheme of this embodiment, the number of the first electrode sheet winding turns is n, n≥30, the number of the first electrode sheet winding turns is large, and the radial dimension of the interval winding turn G inside the electrode assembly is small, which increases the difficulty of electrolyte backflow. At least one of the first 10 first electrode sheet winding turns is provided with a groove, which can improve the electrolyte backflow through the groove inside the electrode assembly and improve the wettability inside the electrode assembly, thereby effectively improving the cycle performance of the cylindrical battery monomer.

[0051] In some embodiments, the number of the first electrode sheet winding turns is n, n≥30, n is a natural number, and the innermost one of the first electrode sheet winding turns is the first first electrode sheet winding turn. At least the first first electrode sheet winding turn is not provided with a groove.

[0052] By adopting the technical scheme of this embodiment, at least the first first electrode sheet winding turn is not provided with a groove, which is conducive to improving the structural strength of the first first electrode sheet winding turn, reducing the risk of powder falling, damage, or even fracture of the first first electrode sheet winding turn caused by grooving, and improving the capacity and use reliability of the cylindrical battery monomer. In addition, the first first electrode sheet winding turn is not provided with a groove, which can also reduce the number of grooves and improve the production efficiency of the first electrode sheet.

[0053] In some embodiments, at least the first 3 first electrode sheet winding turns are not provided with a groove.

[0054] By adopting the technical scheme of this embodiment, the first to third first pole piece winding turns are not provided with grooves, which is beneficial to improve the structural strength of the first to third first pole piece winding turns, reduce the risk of powder falling, damage, and even breakage of the first to third first pole piece winding turns due to grooving, and improve the capacity and use reliability of the cylindrical battery cell.

[0055] In some embodiments, the electrode assembly is provided with a center hole, and the first first pole piece winding turn is closest to the center hole compared with other first pole piece winding turns.

[0056] By adopting the technical scheme of this embodiment, the center hole can be used to accommodate electrolyte and also allow electrolyte to flow, thereby allowing the first pole piece winding turns located on the inner side to be soaked, improving the soaking effect on the inner side of the electrode assembly, improving the cycle performance of the cylindrical battery cell, and in addition, the first pole piece winding turns located on the inner side can be soaked by the electrolyte in the center hole, which can reduce the need for grooves on the first pole piece winding turns located on the inner side, improve the structural strength of the first pole piece winding turns on the inner side, and reduce the problem of powder falling of the first pole piece winding turns on the inner side, thereby effectively balancing the capacity, cycle performance, and use reliability of the cylindrical battery cell.

[0057] In some embodiments, the number of first pole piece winding turns is n, n > 30, and n is a natural number; the first pole piece winding turn on the innermost side is the first first pole piece winding turn; and at least the last two first pole piece winding turns are not provided with grooves.

[0058] By adopting the technical scheme of this embodiment, at least the last two first pole piece winding turns are not provided with grooves, which is beneficial to improve the structural strength of the last two first pole piece winding turns, reduce the risk of breakage of the last two first pole piece winding turns, and thereby effectively improve the use reliability of the cylindrical battery cell. In addition, the last two first pole piece winding turns are not provided with grooves, which can reduce the number of grooves and improve the production and processing efficiency of the first pole piece.

[0059] In some embodiments, at least the last ten first pole piece winding turns are not provided with grooves.

[0060] By adopting the technical scheme of this embodiment, at least the last ten first pole piece winding turns are not provided with grooves, which is beneficial to improve the structural strength of the last ten first pole piece winding turns, reduce the risk of breakage of the last ten first pole piece winding turns, and thereby effectively improve the use reliability of the cylindrical battery cell. In addition, the last ten first pole piece winding turns are not provided with grooves, which can reduce the number of grooves and improve the production and processing efficiency of the first pole piece.

[0061] In some embodiments, the number of the first pole piece winding turns is n, n>30, n is a natural number; the innermost one of the first pole piece winding turns is the first first pole piece winding turn; the first f first pole piece winding turns are not provided with the groove; the last q first pole piece winding turns are not provided with the groove; all the first pole piece winding turns between the first f first pole piece winding turns and the last q first pole piece winding turns are provided with the groove, f+q<n, f and q are positive integers.

[0062] By adopting the technical scheme of the embodiment, the first f first pole piece winding turns and the last q first pole piece winding turns are not provided with the groove, which is beneficial to improving the structural strength of the inner and outer first pole piece winding turns, improving the use reliability of the cylindrical battery monomer, and in addition, the number of grooves can be reduced, and the production and processing efficiency of the first pole piece can be improved. Moreover, the electrode assembly is grooved in the middle region between the inner and outer sides, which is beneficial to improving the impregnation effect of the electrode assembly in the middle region between the inner and outer sides, and improving the cycle performance of the battery monomer.

[0063] In some embodiments, 30n<80, and optionally, 60n<75.

[0064] By adopting the technical scheme of the embodiment, the number of the first pole piece winding turns is large, the capacity of the cylindrical battery monomer is large, and the impregnation difficulty of the electrode assembly is large. In the embodiment, the groove can be selectively arranged on the inner side or the outer side of the electrode assembly, so as to improve the impregnation effect of the electrode assembly, and the structural strength of the inner side or the outer side of the electrode assembly can be improved, and the use reliability, capacity and cycle performance of the electrode assembly can be considered.

[0065] In some embodiments, the number of the first pole piece winding turns provided with the groove is v, 0.23v / n<1, v and n are positive integers, and optionally, 0.3v / n<0.7.

[0066] By adopting the technical scheme of the embodiment, the first pole piece winding turns can be selectively grooved, which is beneficial to simultaneously considering the manufacturing of the first pole piece, the use reliability of the battery monomer and the cycle performance of the battery monomer.

[0067] In some embodiments, the first pole piece has a first winding end, the second pole piece has a second winding end, the innermost first pole piece winding turn is the first first pole piece winding turn, and the second winding end is located between the last two first pole piece winding turns; the positions corresponding to the end surface of the first winding end of the last two first pole piece winding turns are not provided with the groove; and / or, the positions corresponding to the end surface of the second winding end of the last two first pole piece winding turns are not provided with the groove.

[0068] By adopting the technical scheme of the embodiment, the risk that the last two first tab winding turns are cut by the end face of the first winding end and / or the end face of the second winding end can be reduced, and the use reliability of the cylindrical battery cell is improved.

[0069] In some embodiments, the last two first tab winding turns are provided with grooves, and the grooves are arranged away from at least one of the end face of the first winding end and the end face of the second winding end; or, the last two first tab winding turns are not provided with grooves.

[0070] By adopting the technical scheme of the embodiment, the risk that the last two first tab winding turns are cut by the end face of the first winding end and / or the end face of the second winding end can be reduced, and the use reliability of the cylindrical battery cell is improved.

[0071] In some embodiments, the first tab has a first winding starting end, the second tab has a second winding starting end, the innermost first tab winding turn is the first first tab winding turn, and the second winding starting end is located between the first two first tab winding turns; the first two first tab winding turns are not provided with grooves at positions corresponding to the end face of the first winding starting end; and / or, the first two first tab winding turns are not provided with grooves at positions corresponding to the end face of the second winding starting end.

[0072] By adopting the technical scheme of the embodiment, the risk that the first two first tab winding turns are cut by the end face of the first winding starting end and / or the end face of the second winding starting end can be reduced, and the use reliability of the cylindrical battery cell is improved.

[0073] In some embodiments, the first two first tab winding turns are provided with grooves, and the grooves are arranged away from at least one of the end face of the first winding starting end and the end face of the second winding starting end; or, the first two first tab winding turns are not provided with grooves.

[0074] By adopting the technical scheme of the embodiment, the risk that the first two first tab winding turns are cut by the end face of the first winding starting end and / or the end face of the second winding starting end can be reduced, and the use reliability of the cylindrical battery cell is improved.

[0075] In some embodiments, the first tab is a negative tab, and the second tab is a positive tab; or, the second tab is a negative tab, and the first tab is a positive tab.

[0076] By adopting the technical scheme of the embodiment, the polarity of the first tab and the second tab can be flexibly set to meet different use requirements.

[0077] In some embodiments, the first active material layer comprises a first active material portion and a second active material portion arranged along the axial direction of the cylindrical battery cell, the first active material portion is connected with the second active material portion at at least one end along the axial direction of the cylindrical battery cell, and the thickness of the second active material portion is less than the thickness of the first active material portion.

[0078] By adopting the technical solutions of this embodiment, the thickness of the second active material portion is less than the thickness of the first active material portion, so that the surface of the second active material portion away from the first current collector is closer to the first current collector than the surface of the first active material portion away from the first current collector. On the one hand, the rolling force on the edge portion of the first active material layer during the rolling of the first electrode sheet can be reduced, and the risk of cracking of the edge portion of the first active material layer can be reduced. On the other hand, the side portion of the second active material portion away from the first current collector can accommodate more electrolyte, thereby facilitating the backflow of the electrolyte, and the thickness difference between the second active material portion and the first active material portion can be utilized to form a siphon effect, thereby improving the speed of electrolyte backflow, improving the wettability of the electrode assembly, and improving the cycle performance of the cylindrical battery cell.

[0079] In some embodiments, along the direction in which the first active material portion points to the second active material portion, the thickness of the second active material portion decreases.

[0080] By adopting the technical solutions of this embodiment, the side portion of the second active material portion away from the first current collector can form a flared structure, the large end of the flared structure is arranged away from the first active material portion, and the flared structure can make the electrolyte more easily be sucked into the space between the first active material portion and the second electrode sheet, thereby more favorably improving the wettability of the electrode assembly and the cycle performance of the cylindrical battery cell.

[0081] In some embodiments, the first active material portion has a first surface away from the first current collector, and the second active material portion has a second surface away from the first current collector, and the second surface is closer to the first current collector than the first surface.

[0082] By adopting the technical solutions of this embodiment, the side portion of the second surface away from the first current collector has more space for accommodating electrolyte, and the distance difference between the second surface and the first surface and the first current collector can be utilized to form a siphon effect, thereby improving the speed of electrolyte backflow, improving the wettability of the electrode assembly, and improving the cycle performance of the cylindrical battery cell.

[0083] In some embodiments, the first active material portion is provided with a groove, and the second active material portion is arranged away from the groove along the axial direction of the cylindrical battery cell.

[0084] By adopting the technical scheme of the embodiment, the first active material part is provided with the groove, the impregnation effect of the first active material part can be improved, the cycle performance of the cylindrical battery monomer is improved, the second active material part is arranged in the interval of the groove, the structural strength of the second active material part can be improved, the risk of powder falling or even collapse of the second active material part due to winding can be reduced, the capacity and use reliability of the cylindrical battery monomer can be improved, and therefore, the cycle performance, capacity and use reliability of the cylindrical battery monomer can be considered.

[0085] In some embodiments, along the axial direction of the cylindrical battery monomer, the distance between the second active material part and the groove is S1, wherein 0mm

[0086] By adopting the technical scheme of the embodiment, the groove does not extend to the second active material part, the structural strength of the second active material part can be improved, the risk of powder falling or even collapse of the second active material part due to winding can be reduced, the capacity and use reliability of the cylindrical battery monomer can be improved, the electrolyte located on the side of the second active material part away from the first current collector can be close to the groove, the electrolyte can flow into the groove better, the impregnation effect of the first pole piece is improved, the cycle performance of the cylindrical battery monomer is improved, and therefore, the cycle performance, capacity and use reliability of the cylindrical battery monomer can be considered.

[0087] In some embodiments, the first pole piece is a negative pole piece.

[0088] By adopting the technical scheme of the embodiment, the first pole piece is a negative pole piece, the first active material part and the second active material part include negative active materials, the groove is arranged in the interval of the second active material part, the groove does not extend to the second active material part, the negative active material of the second active material part is not subjected to a groove processing operation, the negative active material of the second active material part is more, the risk of lithium precipitation of the cylindrical battery monomer is reduced, and the use performance of the cylindrical battery monomer is improved.

[0089] In some embodiments, along the axial direction of the cylindrical battery monomer, one end of the first active material part is connected with the second active material part, the other end of the first active material part is not connected with the second active material part, the surface of the first active material part away from the current collector is provided with the groove, along the axial direction of the cylindrical battery monomer, the groove penetrates through the end surface of the first active material part away from the second active material part; or, along the axial direction of the cylindrical battery monomer, the end surface of the first active material part away from the second active material part is arranged in the interval of the groove.

[0090] By adopting the technical scheme of the embodiment, the groove can be flexibly arranged on the first active material part to meet different use requirements.

[0091] In some embodiments, the distance between the end surface of the first active material portion facing away from the second active material portion and the groove is s, and 0mm≤s≤20mm, optionally, 0.1mm≤s≤8mm; optionally, 0.5mm≤s≤3mm.

[0092] By adopting the technical solutions of this embodiment, the distance between the end surface of the first active material portion facing away from the second active material portion and the groove is close, and the electrolyte between the end surface of the first active material portion facing away from the second active material portion and the shell can flow into the groove quickly, thereby improving the impregnation effect of the first tab and facilitating improvement of the cycle performance of the cylindrical battery monomer.

[0093] In some embodiments, along the axial direction of the cylindrical battery monomer, both ends of the first active material portion are connected with the second active material portion.

[0094] By adopting the technical solutions of this embodiment, the first tab can accommodate more electrolyte at both ends in the first direction and form a siphon effect, thereby facilitating the reflux of the electrolyte, improving the impregnation effect of the electrode assembly, and improving the cycle performance of the cylindrical battery monomer.

[0095] In some embodiments, the first current collector includes a first current collector main body and a first tab arranged and connected along the axial direction of the cylindrical battery monomer, at least part of the first current collector main body is covered with the first active material layer, and the first tab is not covered with the first active material layer.

[0096] By adopting the technical solutions of this embodiment, the first tab is led out from the end of the first tab along the axial direction of the cylindrical battery monomer, and the electrical connection of the first tab with other components can be facilitated.

[0097] In some embodiments, the number of the first active material layers is two, the two first active material layers cover two surfaces of the first current collector along the thickness direction of the first current collector respectively, and at least one of the first active material layers is provided with a groove.

[0098] By adopting the technical solutions of this embodiment, the number of the active materials of the first tab can be increased by providing two first active material layers, which is conducive to improving the capacity of the cylindrical battery monomer; in addition, the groove is also more flexible to meet different use requirements.

[0099] In some embodiments, the number of the grooves is multiple, the multiple grooves include first grooves and second grooves formed along the axial direction of the cylindrical battery monomer, among the two first active material layers, one of the first active material layers is provided with the multiple first grooves, and the other of the first active material layers is provided with the multiple second grooves; along the thickness direction of the first current collector, the first grooves and the second grooves are arranged staggeredly.

[0100] By adopting the technical scheme of the embodiment, the two first active material layers are respectively provided with the plurality of first grooves and the plurality of second grooves, so as to improve the infiltration effect of the two first active material layers and improve the cycle performance of the cylindrical battery monomer; in addition, the first grooves and the second grooves are arranged in a staggered manner along the thickness direction of the first current collector, which is beneficial to improving the structural strength of the first pole piece and improving the use reliability of the cylindrical battery monomer.

[0101] In some embodiments, the plurality of first grooves and the plurality of second grooves are arranged alternately along the winding direction of the electrode assembly.

[0102] By adopting the technical scheme of the embodiment, the plurality of first grooves and the plurality of second grooves can be uniformly distributed on the two first active material layers, which can improve the uniformity of the distribution of the electrolyte in the cylindrical battery monomer and is beneficial to improving the cycle performance of the cylindrical battery monomer.

[0103] In some embodiments, the spacing between adjacent first grooves and second grooves along the winding direction of the electrode assembly is C, wherein C≥1.5mm, optionally, 1.8mm≤C≤5mm, and optionally, 2mm≤C≤3mm.

[0104] By adopting the technical scheme of the embodiment, the density of the first grooves and the second grooves is reasonably set, which can reduce the loss amount of the active material of the first active material layer and is also beneficial to improving the structural strength of the first pole piece, so that the capacity, use reliability and energy density of the cylindrical battery monomer can be considered.

[0105] In some embodiments, the first current collector includes a first current collector body and a first tab connected to each other, at least part of the first current collector body is covered with the first active material layer, and the first tab is not covered with the first active material layer; the second current collector includes a second current collector body and a second tab connected to each other, at least part of the second current collector body is covered with the second active material layer, and the second tab is not covered with the second active material layer.

[0106] In some embodiments, the shell includes a shell body and an end cover, the shell body includes a side wall and an end wall connected to each other, the side wall surrounds the electrode assembly, the end wall and the end cover are distributed opposite to each other along the axial direction of the cylindrical battery monomer, and the end cover is sealingly connected to the side wall; the end cover is insulatively provided with an electrode terminal, the second tab is electrically connected to the electrode terminal, and at least one of the side wall and the end wall is electrically connected to the first tab; or, the end wall is insulatively provided with an electrode terminal, the second tab is electrically connected to the electrode terminal, and at least one of the end cover and the side wall is electrically connected to the first tab.

[0107] By adopting the technical scheme of the embodiment, the output electrode of the cylindrical battery monomer can be flexibly arranged to meet different requirements.

[0108] In some embodiments, the cylindrical battery cell further comprises a first current collecting member and a second current collecting member; the first tab and the second tab are respectively located at two ends of the electrode assembly along the axial direction of the cylindrical battery cell, and the second tab is located at a side of the electrode assembly close to the electrode terminal; the second current collecting member is electrically connected between the second tab and the electrode terminal; the electrode terminal is insulated and arranged on the end cover, the first current collecting member is located between the first tab and the end wall, the first current collecting member is electrically connected with the first tab, and at least one of the side wall and the end wall is electrically connected with the first current collecting member; or, the electrode terminal is insulated and arranged on the end wall, the first current collecting member is located between the first tab and the end cover, the first current collecting member is electrically connected with the first tab, and at least one of the side wall and the end cover is electrically connected with the first current collecting member.

[0109] By adopting the technical scheme of the embodiment, the switching effect of the first current collecting member and the second current collecting member makes the assembly operation of the cylindrical battery cell simpler.

[0110] In some embodiments, the electrode terminal is insulated and arranged on the end wall; the side wall is provided with a protruding portion protruding inward, and along the axial direction of the cylindrical battery cell, the protruding portion is located at a side of the first tab facing the end cover; the second current collecting member comprises a first connecting portion, a second connecting portion and a third connecting portion, the second connecting portion is connected between the first connecting portion and the third connecting portion; the first connecting portion is connected to the first tab, at least part of the third connecting portion is located between the protruding portion and the end cover, and the third connecting portion is connected to a side of the protruding portion facing away from the first tab.

[0111] By adopting the technical scheme of the embodiment, at least part of the third connecting portion is arranged between the protruding portion and the end cover, and the third connecting portion is connected to a side of the protruding portion facing the end cover, so that the first current collecting member can be assembled through the opening of the shell, and the installation of the first current collecting member is facilitated; in addition, the protruding portion also limits the third connecting portion, improves the installation stability of the first current collecting member, improves the connection reliability between the first current collecting member and the first tab and between the first current collecting member and the protruding portion, and improves the use reliability of the cylindrical battery cell.

[0112] In a second aspect, a battery device is provided, comprising a plurality of the cylindrical battery cells described above.

[0113] By adopting the technical scheme of the embodiment, the cylindrical battery cell has good cycle performance, good use reliability and high energy density, which is conducive to improving the use performance and service life of the battery device.

[0114] In a third aspect, a power utilization device is provided, comprising the cylindrical battery cell described above or the battery device described above, and the battery cell or the battery device is used for storing or providing electric energy.

[0115] By adopting the technical scheme of the embodiment, the cylindrical battery monomer has good cycle performance, good use reliability and high energy density, the battery device has good use performance and long service life, and the use performance and service life of the electric device are improved.

[0116] The above description is only a summary of the technical scheme of the present application, in order to more clearly understand the technical means of the present application, the content of the specification can be implemented, and in order to make the above and other purposes, characteristics and advantages of the present application more obvious and easy to understand, the following specific embodiments of the present application are described. BRIEF DESCRIPTION OF DRAWINGS

[0117] In order to more clearly illustrate the technical scheme in the embodiments of the present application, the drawings needed in the embodiments or prior art description will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and those skilled in the art can obtain other drawings according to these drawings without creating any creative labor.

[0118] Figure 1 The structural schematic diagram of the vehicle provided for some embodiments of the present application is shown in the figure;

[0119] Figure 2 The schematic diagram of the battery device provided for some embodiments of the present application is shown in the figure;

[0120] Figure 3 The structural schematic diagram of the cylindrical battery monomer provided for some embodiments of the present application is shown in the figure;

[0121] Figure 4 The exploded schematic diagram of the cylindrical battery monomer is shown in the figure; Figure 3

[0122] The sectional view schematic diagram of the cylindrical battery monomer is shown in the figure; Figure 5

[0123] The partial sectional view schematic diagram of the electrode assembly of the cylindrical battery monomer provided for some embodiments of the present application is shown in the figure; Figure 6

[0124] The sectional view schematic diagram of the cylindrical battery monomer is shown in the figure; Figure 7 Figure 6 The partial enlarged view of B in the figure is shown in the figure;

[0125] Figure 8 Figure 6 The structural schematic diagram of the first pole piece in the unfolded state provided for some embodiments of the present application is shown in the figure;

[0126] Figure 9 The structural schematic diagram of the first pole piece in the unfolded state provided for some embodiments of the present application is shown in the figure;

[0127] Figure 10 ​​A structural schematic view of the first pole piece in an unfolded state is provided for some other embodiments of the present application.

[0128] Figure 11 A structural schematic view of the first pole piece in an unfolded state is provided for some other embodiments of the present application.

[0129] Figure 12 A structural schematic view of the first pole piece in an unfolded state is provided for some other embodiments of the present application.

[0130] Figure 13 A structural schematic view of the first pole piece in an unfolded state is provided for some other embodiments of the present application.

[0131] Figure 14 A structural schematic view of the first pole piece in an unfolded state is provided for some other embodiments of the present application.

[0132] Figure 15 A structural schematic view of the first pole piece in an unfolded state is provided for some other embodiments of the present application.

[0133] Figure 16 A structural schematic view of the first pole piece in an unfolded state is provided for some other embodiments of the present application. Figure 15 A sectional view at C-C in FIG. 8.

[0134] Figure 17 A structural schematic view of the first pole piece in an unfolded state is provided for some other embodiments of the present application.

[0135] Figure 18 A structural schematic view of the first pole piece in an unfolded state is provided for some other embodiments of the present application. Figure 17 A sectional view at D-D in FIG. 9.

[0136] Figure 19 A structural schematic view of the first pole piece in an unfolded state is provided for some other embodiments of the present application.

[0137] Figure 20 A structural schematic view of the first pole piece in an unfolded state is provided for some other embodiments of the present application.

[0138] Figure 21 A structural schematic view of the first pole piece in an unfolded state is provided for some other embodiments of the present application.

[0139] Figure 22 A structural schematic view of the first pole piece in an unfolded state is provided for some other embodiments of the present application.

[0140] Figure 23 A structural schematic view of the first pole piece in an unfolded state is provided for some other embodiments of the present application.

[0141] Figure 24 A structural schematic view of the first pole piece in an unfolded state is provided for some other embodiments of the present application.

[0142] Figure 25 A structure schematic view of the first pole piece in an unfolded state is provided for some other embodiments of the present application;

[0143] Figure 26 A structure schematic view of the first pole piece in an unfolded state is provided for some other embodiments of the present application; Figure 25 A cutaway schematic view at E-E in FIG. 4;

[0144] Figure 27 A cutaway schematic view at E-E in FIG. 4; Figure 25 A cutaway schematic view at F-F in FIG. 4;

[0145] Figure 28 A cutaway schematic view of a cylindrical battery cell is provided for some other embodiments of the present application;

[0146] Figure 29 A cutaway schematic view of a cylindrical battery cell is provided for some other embodiments of the present application; Figure 28 A local enlarged view at H in FIG. 4;

[0147] Figure 30 A cutaway schematic view of a cylindrical battery cell is provided for some other embodiments of the present application;

[0148] In the drawings, reference numerals:

[0149] 1 vehicle; 2 battery device; 3 controller; 4 motor; 5 case; 51 first case; 52 second case; 6 cylindrical battery cell; 10 electrode assembly; 101 center hole; 11 positive electrode sheet; 111 positive electrode current collector; 112 positive electrode active material layer; 12 negative electrode sheet; 121 negative electrode current collector; 122 negative electrode active material layer; 13 separator; 14 first electrode sheet; 141 first current collector; 1411 first current collector body; 1412 first tab; 142 first active material layer; 1421 first surface; 1421c measurement region; 1421d outer edge line; 1422 first active material portion; 1423 second active material portion; 1424 first face; 1425 second face; 143 first electrode sheet winding; 1431 first current collector winding; 1432 first active material winding; 1433 first winding face; 144 recess; 144b notch; 1441 first recess; 1442 first groove segment; 1443 second groove segment; 1444 second recess; 1445 subsegment; 1446 first groove; 1447 second groove; 15 second electrode sheet; 151 second current collector; 1511 second current collector body; 1512 second tab; 152 second active material layer; 1521 second surface; 153 second electrode sheet winding; 1531 second current collector winding; 1532 second active material winding; 1533 second winding face; 20 housing; 21 housing body; 211 end wall; 212 side wall; 2121 protrusion; 2122 recess; 2123 crimping portion; 22 end cap; 30 electrode terminal; 31 through hole; 40 cover plate; 60 first current collecting member; 61 first connecting portion; 62 second connecting portion; 63 third connecting portion; 70 second current collecting member; 80 insulating member. DETAILED DESCRIPTION

[0150] In order to make the technical problems to be solved, technical solutions and beneficial effects of the present application more clearly, the present application will be further described in detail below in conjunction with the drawings and embodiments. It should be understood that the specific embodiments described herein are only intended to explain the present application, and are not intended to limit the present application.

[0151] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present application; the present specification and claims and the aforementioned description of the drawings herein contain the terms "comprising" and "having" and any variations thereof, which are intended to cover a non-exclusive inclusion.

[0152] In the description of the embodiments of the present application, the technical terms "first", "second" and the like are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features.

[0153] Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearance of the phrase in various places in the specification does not necessarily all refer to the same embodiment, nor is it necessarily independent or alternative embodiments to each other. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined in any suitable manner with other embodiments.

[0154] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B, which can represent the three cases of A alone, A and B together, and B alone. In addition, the character " / " in this paper generally represents that the front and rear associated objects are a "or" relationship.

[0155] In the description of the embodiments of the present application, the term "a plurality of" refers to two or more (including two), and similarly, "a plurality of groups" refers to two or more groups (including two groups), and "a plurality of pieces" refers to two or more pieces (including two pieces). The meaning of "several" is one or more, unless otherwise explicitly and specifically limited.

[0156] In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the embodiments of the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the embodiments of the present application.

[0157] In the description of the embodiments of the present application, unless specifically defined and limited otherwise, the terms "mount", "connected", "connection", "fixed", and the like should be interpreted broadly, for example, can be fixed connection, can also be detachable connection, or integral; can be mechanical connection, can also be electrical connection; can be direct connection, can also be indirect connection through an intermediate medium, or the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0158] In the description of the embodiments of the present application, unless specifically defined and limited otherwise, when an element is referred to as "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0159] The cylindrical battery cell can be a cylindrical secondary battery, which refers to a battery cell that can be activated by charging after discharging to continue to be used.

[0160] The battery device can refer to a single physical module including one or more cylindrical battery cells to provide higher voltage and capacity.

[0161] The cylindrical battery cell generally includes an electrode assembly and a housing for accommodating the electrode assembly. The electrode assembly generally includes a separator and two polar plates of opposite polarity, and the separator separates the two polar plates.

[0162] In the cylindrical battery cell, the electrode assembly is in a wound structure, and the two polar plates and the separator are stacked and wound in the winding direction of the electrode assembly. During the cyclic charging and discharging process of the cylindrical battery cell, the active material layer of the polar plate expands, causing the electrode assembly to expand. The expansion of the electrode assembly will squeeze the housing. In particular, for large-diameter cylindrical battery cells, the number of winding turns of the electrode assembly is large, the cumulative expansion force of the electrode assembly is large, and the squeezing force of the electrode assembly on the housing is large, increasing the risk of deformation or even rupture of the housing, affecting the use reliability of the cylindrical battery cell. In order to alleviate the expansion of the electrode assembly, a gap is provided between the active material layers of the two polar plates, which provides expansion space for the electrode assembly, absorbs the expansion force, and reduces the squeezing force on the housing. However, the gap will occupy a part of the space in the cylindrical battery cell, which is not conducive to the improvement of the energy density of the large-diameter cylindrical battery cell. Therefore, how to better balance the use reliability and the energy density of the cylindrical battery cell.

[0163] In view of this, the embodiments of the present application provide a technical scheme, which reasonably designs the interval between the active material layers of the two pole pieces, thereby reducing the swelling force, reducing the deformation of the shell, improving the use reliability of the cylindrical battery monomer, in addition, the internal space of the cylindrical battery monomer can also be fully utilized, and the energy density of the cylindrical battery monomer is improved, therefore, the cylindrical battery monomer of the embodiments of the present application can better balance the energy density and use reliability of the cylindrical battery monomer.

[0164] The cylindrical battery monomer described in the embodiments of the present application is suitable for a battery device and a power consumption device using the battery device. The power consumption device can be a device using the battery device as a power supply or various energy storage systems using the battery device as an energy storage element. The power consumption device can be, but is not limited to, a mobile phone, a tablet, a notebook computer, an electric toy, an electric tool, an electric vehicle, an electric vehicle, a ship, a spacecraft, etc. Among them, the electric toy can include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric plane toys, etc. The spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.

[0165] The following embodiments are described for convenience with the power consumption device as a vehicle 1.

[0166] As shown in Figure 1 , the vehicle 1 is provided with a battery device 2, which can be arranged at the bottom, head or tail of the vehicle 1. The battery device 2 can be used for power supply of the vehicle 1, for example, the battery device 2 can be used as the operating power supply of the vehicle 1.

[0167] The vehicle 1 can also include a controller 3 and a motor 4, the controller 3 is used to control the battery device 2 to supply power to the motor 4, for example, for the working power demand of the vehicle 1 during starting, navigation and driving.

[0168] In some embodiments of the present application, the battery device 2 can not only be used as the operating power supply of the vehicle 1, but also be used as the driving power supply of the vehicle 1, instead of or partially instead of fuel or natural gas to provide driving power for the vehicle 1.

[0169] Referring to Figure 2 , in some embodiments, the battery device 2 can include one or more battery monomer assemblies for providing voltage and capacity.

[0170] The battery monomer assembly can include a plurality of cylindrical battery monomers 6, and the plurality of cylindrical battery monomers 6 are connected in series, in parallel or in mixed connection through the current collection components. The mixed connection means that there are both series connection and parallel connection in the plurality of cylindrical battery monomers 6.

[0171] The cylindrical battery cell 6 can be a secondary battery cell, which refers to a battery cell that can be used continuously after the activation of active materials by charging after the discharge of the battery cell.

[0172] As an example, the cylindrical battery cell 6 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, or the like.

[0173] In some embodiments, the battery cell assembly is generally formed by arranging a plurality of cylindrical battery cells 6; as an example, the battery cell assembly can be a battery module, which is formed by arranging and fixing a plurality of cylindrical battery cells 6 into one independent module. As an example, the battery module can be formed by bundling a plurality of cylindrical battery cells 6 with a cable tie.

[0174] In some embodiments, the battery device 2 can be a battery pack, which includes a box 5 and one or more battery cell assemblies accommodated in the box 5. As an example, the battery cell assembly can be a battery module, which can be accommodated in the box 5 by fixing the battery module in the box 5. As an example, the battery cell assembly can also be accommodated in the box 5 by directly fixing a plurality of cylindrical battery cells 6 in the box 5.

[0175] In some embodiments, the box 5 for accommodating the cylindrical battery cell 6 can be of various structures.

[0176] In some embodiments, the box 5 can include a first box 51 and a second box 52. The first box 51 and the second box 52 are fastened so that a closed space is formed inside the box 5 to accommodate the battery cell assembly. The closed here means covered or closed, which can be sealed or unsealed. The first box 51 can be a top cover or a bottom plate.

[0177] In some embodiments, the box 5 can include a top cover, a frame, and a bottom plate. The top cover and the bottom plate are connected with the frame, so that a closed space is formed inside the box 5 to accommodate the battery cell assembly. As an example, the frame can include a plurality of side beams.

[0178] In some embodiments, the box 5 can be part of the chassis structure of the vehicle 1. For example, part of the box 5 can become at least part of the floor of the vehicle 1, or part of the box 5 can become at least part of the cross beam and the longitudinal beam of the vehicle 1.

[0179] In some embodiments, the battery device 2 can be an energy storage device.

[0180] The energy storage device can be used in an energy storage power station, a wind power system, a solar power system, a mobile power system, or a temporary power supply system, etc. The energy storage device can store electric energy as needed and output the electric energy at an appropriate time. For example, the energy storage device can store electric energy during a low electricity consumption period and provide electric energy for relevant users or electric equipment during a high electricity consumption period.

[0181] In some embodiments, the energy storage device includes an energy storage container, an energy storage cabinet, etc.

[0182] Referring to Figures 3-8 As shown in the drawings, the embodiments of the present application provide a cylindrical battery cell 6, which includes a housing 20 and an electrode assembly 10, at least a part of the electrode assembly 10 being accommodated in the housing 20.

[0183] The housing 20 can be a hollow structure, and an accommodation space for accommodating the electrode assembly 10 and an electrolyte is formed in the housing 20. Exemplarily, the housing 20 of the cylindrical battery cell 6 is a cylindrical housing 20.

[0184] In some embodiments, the housing 20 can be a metal housing 20, for example, the housing 20 can be a steel shell, an aluminum shell, a composite metal shell (such as a copper-aluminum composite shell), or other metal shells. Alternatively, the housing 20 can also be a non-metal housing, for example, a plastic shell (such as polypropylene), etc.

[0185] In some embodiments, the housing 20 includes a shell 21 and an end cover 22, the shell 21 has an opening, and the end cover 22 is connected to the shell 21 and covers the opening.

[0186] The shell 21 is a component for cooperating with the end cover 22 to form an internal cavity of the cylindrical battery cell 6, and the internal cavity formed can be used to accommodate the electrode assembly 10, the electrolyte, and other components.

[0187] The shell 21 and the end cover 22 can be independent components. Exemplarily, an opening can be provided on the shell 21, and the internal cavity of the battery cell can be formed by covering the opening with the end cover 22.

[0188] The material of the shell 21 can be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, etc.

[0189] The shape of the end cover 22 can be adapted to the shape of the shell 21 to cooperate with the shell 21. The material of the end cover 22 can be the same as or different from the material of the shell 21. Alternatively, the end cover 22 can be made of a material (such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc.) having a certain hardness and strength, so that the end cover 22 is not easy to deform when subjected to extrusion and collision, and the battery cell can have higher structural strength and improved reliability.

[0190] The end cover 22 is connected to the housing 21 by welding, bonding, clamping, or other means.

[0191] The housing 21 can be open at one end or both ends. In some examples, the housing 21 can be a structure open at one side, and the end cover 22 is provided as one and covers the housing 21. In other examples, the housing 21 can also be a structure open at both sides, and the end cover 22 is provided as two, and the two end covers 22 cover the two openings of the housing 21 respectively.

[0192] In some embodiments, the housing 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 6, and the end cover 22 is sealingly connected to the side wall 212.

[0193] The electrode assembly 10 is a component in which an electrochemical reaction occurs in the cylindrical battery cell 6. The electrode assembly 10 can be entirely accommodated in the outer shell 20, or can be partially accommodated in the outer shell 20. For example, a portion of the tab of the electrode assembly 10 can extend outside the outer shell 20.

[0194] Optionally, the electrode assembly 10 is entirely accommodated in the outer shell 20.

[0195] In some embodiments, the diameter of the cylindrical battery cell is greater than or equal to 40 mm. The large-diameter cylindrical battery cell has a higher capacity, which is beneficial to improving the energy density when a plurality of cylindrical battery cells are assembled into a group.

[0196] In some embodiments, the outer diameter of the outer shell 20 is greater than or equal to 40 mm. The outer diameter of the outer shell 20 can be the outer diameter of the outer shell 20.

[0197] The outer shell 20 has a larger diameter to increase its internal space and improve the capacity of the cylindrical battery cell.

[0198] In some embodiments, the electrode assembly 10 includes a positive electrode sheet 11 and a negative electrode sheet 12. During charging and discharging of the cylindrical battery cell 6, active ions (e.g., lithium ions) are inserted and extracted between the positive electrode sheet 11 and the negative electrode sheet 12.

[0199] In some embodiments, the positive electrode sheet 11 can include a positive electrode current collector 111 and a positive electrode active material layer 112 provided on at least one surface of the positive electrode current collector 111.

[0200] As an example, the positive electrode current collector 111 has two surfaces opposite in the thickness direction thereof, and the positive electrode active material layer 112 is provided on either one or both of the two opposite surfaces of the positive electrode current collector 111.

[0201] As an example, the positive electrode current collector 111 can employ a metal foil, a conductive polymer material, a carbon material, or a composite current collector. For example, as a metal foil, a pure metal, an alloy, a surface-treated metal, including but not limited to stainless steel, copper, aluminum, nickel, a nickel alloy, titanium, or silver, and the like can be employed. The composite current collector can include a high molecular material base layer and a metal layer. The composite current collector can be formed by forming a metal material (aluminum, an aluminum alloy, nickel, a nickel alloy, titanium, a titanium alloy, silver, and a silver alloy, and the like) on a high molecular material base material (such as a base material of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, and the like).

[0202] As an example, the positive electrode active material layer 112 includes a positive electrode active material, which can include at least one of a lithium-containing phosphate, a lithium transition metal oxide, and a modified compound of each thereof. However, the present application is not limited to these materials, and other conventional materials that can be used as a battery positive electrode active material can also be used. These positive electrode active materials can be used alone only one or two or more can be used in combination. Examples of the lithium-containing phosphate can include, but are not limited to, at least one of lithium iron phosphate (such as LiFeP04 (which can also be referred to simply as LFP)), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnP04), a composite material of lithium manganese phosphate and carbon, lithium manganese iron phosphate, and a composite material of lithium manganese iron phosphate and carbon. Examples of the lithium transition metal oxide can include, but are not limited to, lithium cobalt oxide (such as LiCo02), lithium nickel oxide (such as LiNi02), lithium manganese oxide (such as LiMn02, LiMn204), 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 simply as NCM 333 ), LiNi 0.5 Co 0.2 Mn 0.3 O2 (which can also be referred to simply as NCM 523 ), LiNi 0.5 Co 0.25 Mn 0.25 O2 (which can also be referred to simply as NCM 211 ), LiNi 0.6 Co 0.2 Mn 0.2 O2 (which can also be referred to simply as NCM 622 ), LiNi 0.8 Co 0.1 Mn 0.1 O2 (which can also be referred to simply as NCM 811 ), lithium nickel cobalt aluminum oxide (such as LiNi 0.8 Co 0.15 Al0.05 O2) and modified compounds thereof, and the like. The modified compounds refer to substances obtained by modification means such as doping or coating on the basis of the above-mentioned substances.

[0203] In some embodiments, the negative electrode sheet 12 can include a negative electrode current collector 121 and a negative electrode active material layer 122 provided on at least one surface of the negative electrode current collector 121.

[0204] As an example, the negative electrode current collector 121 has two surfaces opposite in the thickness direction thereof, and the negative electrode active material layer 122 is provided on either one or both of the two surfaces of the negative electrode current collector 121.

[0205] As an example, the negative electrode current collector 121 can employ a metal foil, a conductive polymer material, a carbon material, or a composite current collector. For example, as the metal foil, a pure metal, an alloy, a surface-treated metal, including but not limited to stainless steel, copper, aluminum, nickel, a nickel alloy, titanium, or silver, and the like can be employed. The composite current collector can include a polymer material base layer and a metal layer. The composite current collector can be formed by forming a metal material (copper, a copper alloy, nickel, a nickel alloy, titanium, a titanium alloy, silver, and a silver alloy, and the like) on a polymer material base material (such as a base material of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, and the like).

[0206] As an example, the negative electrode active material can employ a negative electrode active material for a cylindrical battery cell 6 known in the art. As an example, the negative electrode active material can include at least one of artificial graphite, natural graphite, soft carbon, hard carbon, a silicon-based material, a tin-based material, lithium titanate, and the like. The silicon-based material can be selected from at least one of elemental silicon, a silicon oxide compound, a silicon-carbon composite, a silicon-nitrogen composite, and a silicon alloy. The tin-based material can be selected from at least one of elemental tin, a tin oxide compound, and a tin alloy. However, the present application is not limited to these materials, and other conventional materials that can be used as a negative electrode active material for a cylindrical battery cell 6 can also be used. These negative electrode active materials can be used alone only or in combination of two or more.

[0207] In some embodiments, the material of the positive electrode current collector 111 can be aluminum, and the material of the negative electrode current collector 121 can be copper.

[0208] In some embodiments, the electrode assembly 10 further includes a separator 13 provided between the positive electrode sheet 11 and the negative electrode sheet 12. The separator 13 can function to prevent short circuiting of the positive and negative electrodes while allowing the passage of active ions.

[0209] The separator 13 can be partially positioned between the positive electrode sheet 11 and the negative electrode sheet 12. For example, the separator 13 can protrude from the positive electrode sheet 11 and the negative electrode sheet 12 at both ends in the axial direction Z of the cylindrical battery cell 6. Alternatively, the entire separator 13 can be positioned between the positive electrode sheet 11 and the negative electrode sheet 12.

[0210] In some embodiments, the separator 13 is a separator film. The separator film of the present application can be any known porous structure separator film having good chemical stability and mechanical stability.

[0211] For example, the main material of the separator film can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator film can be a single layer film or a multi-layer composite film, and is not particularly limited. When the separator film is a multi-layer composite film, the materials of the respective layers can be the same or different. The separator 13 can be a separate member positioned between the positive electrode sheet 11 and the negative electrode sheet 12, or can be attached to the surface of the positive electrode sheet 11 or the surface of the negative electrode sheet 12. An inorganic particle coating layer, an organic particle coating layer, or an organic / inorganic composite coating layer can be applied to the surface of the separator film.

[0212] In some embodiments, the cylindrical battery cell 6 further includes an electrolyte that functions to conduct ions between the positive electrode sheet 11 and the negative electrode sheet 12. The electrolyte of the present application can be selected as needed.

[0213] In some embodiments, the electrolyte includes an electrolyte salt and a solvent.

[0214] In some embodiments, the electrolyte salt can be selected from at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bisfluorosulfonylimide, lithium bis-trifluoromethanesulfonylimide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorobisoxalate borate, lithium bisoxalate borate, lithium difluorodioxalate phosphate, and lithium tetrafluorodioxalate phosphate.

[0215] In some embodiments, 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, butanedisulfone, methyl ethyl sulfone, and diethyl sulfone. The solvent can also be an ether-based solvent. The ether-based solvent can include one or more of ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyl tetrahydrofuran, diphenyl ether, and crown ether.

[0216] In some embodiments, an additive can be optionally included in the electrolyte. For example, the additive can include a negative electrode film-forming additive, a positive electrode film-forming additive, and an additive capable of improving certain properties of the cylindrical battery cell 6, such as an additive capable of improving overcharge / fast charge properties of the cylindrical battery cell 6, an additive capable of improving high-temperature properties of the cylindrical battery cell 6, an additive capable of improving low-temperature properties of the cylindrical battery cell 6, and the like.

[0217] In some embodiments, the positive electrode sheet 11, the negative electrode sheet 12, and the separator 13 are wound.

[0218] The electrode assembly 10 is in a wound structure. For example, the positive electrode sheet 11, the separator 13, and the negative electrode sheet 12 are wound in a cylindrical wound structure.

[0219] In some examples, the first electrode sheet 14, the second electrode sheet 15, and the separator 13 are stacked in the thickness direction of the first current collector 141, and then wound from one end of the first electrode sheet 14 to the other end in a certain direction, thereby forming a wound structure. The wound structure can be a cylindrical structure.

[0220] In some examples, the cylindrical battery cell 6 has a center axis X1, which is a geometric center line of the cylindrical battery cell 6, and the axial direction Z of the cylindrical battery cell 6 is parallel or nearly parallel to the center axis X1.

[0221] In the radial direction of the cylindrical battery cell 6, the side of the electrode assembly 10 close to the center axis X1 of the cylindrical battery cell 6 is referred to as the inner side of the electrode assembly 10, and the side of the electrode assembly 10 away from the center axis X1 of the cylindrical battery cell 6 is referred to as the outer side of the electrode assembly 10.

[0222] In some embodiments, the electrode assembly 10 includes the separator 13 and the first electrode sheet 14 and the second electrode sheet 15 having opposite polarities, at least a portion of the separator 13 being located between the first electrode sheet 14 and the second electrode sheet 15.

[0223] One of the first electrode sheet 14 and the second electrode sheet 15 is the positive electrode sheet 11 described above, and the other is the negative electrode sheet 12 described above.

[0224] A portion of the separator 13 is located between the first electrode sheet 14 and the second electrode sheet 15. Alternatively, the entire separator 13 is located between the first electrode sheet 14 and the second electrode sheet 15.

[0225] In some embodiments, the first electrode sheet 14 includes a first current collector 141 and a first active material layer 142, the first active material layer 142 being connected to at least a portion of at least one surface of the first current collector 141 in the thickness direction of the first current collector 141, and at least a portion of the first active material layer 142 being located between the first current collector 141 and the separator 13.

[0226] The first current collector 141 is covered with the first active material layer 142 on one surface thereof in the thickness direction of the first current collector 141, or the first current collector 141 is covered with the first active material layer 142 on both surfaces thereof in the thickness direction of the first current collector 141.

[0227] The first active material layer 142 can cover a partial area of the surface of the first current collector 141, or the first active material layer 142 can cover the entire area of the surface of the first current collector 141.

[0228] The first active material layer 142 can be directly covered on the first current collector 141, or other layer structures, such as a conductive protective layer, can be provided between the first active material layer 142 and the first current collector 141. The conductive protective layer can be formed by mixing a conductive agent and a binder. The binder bonds the first active material layer 142 and the first current collector 141, and the conductive agent is responsible for conducting electrons. The conductive agent can be carbon black, graphite, or the like, and the binder can be polyvinylidene fluoride or the like.

[0229] For example, the first electrode tab 14 is the negative electrode tab 12, the first electrode tab 14 includes the first current collector 141 and the first active material layer 142, the first current collector 141 is the negative current collector 121 described above, and the first active material layer 142 is the negative active material layer 122 described above. Alternatively, the first electrode tab 14 is the positive electrode tab 11, the first current collector 141 is the positive current collector 111 described above, and the first active material layer 142 is the positive active material layer 112 described above.

[0230] The electrode assembly 10 has a wound structure, the first electrode tab 14 is wound in multiple turns along a winding direction V of the electrode assembly 10, the first electrode tab 14 is wound to form multiple first electrode tab winding turns 143, the first current collector 141 includes first current collector winding turns 1431 located in the first electrode tab winding turns 143, and the first active material layer 142 includes first active material winding turns 1432 located in the first electrode tab winding turns 143. The first active material layer 142 has a first surface 1421 facing away from the first electrode tab winding turns 143. The first electrode tab 14 has a first winding start end A1 and a first winding end end A2. The first winding start end A1 can refer to an end of the first electrode tab 14 closest to the central axis X1 of the cylindrical battery cell 6, and the first winding end end A2 can refer to an end of the first electrode tab 14 farthest from the central axis X1 of the cylindrical battery cell 6.

[0231] The first current collector 141 is also wound in multiple turns along the winding direction V of the electrode assembly 10. A winding start end of the first current collector 141 can refer to an end of the first current collector 141 closest to the central axis X1 of the cylindrical battery cell 6, and a winding end end of the first current collector 141 can refer to an end of the first current collector 141 farthest from the central axis X1 of the cylindrical battery cell 6.

[0232] The first active material layer 142 is also wound in multiple turns along the winding direction V of the electrode assembly 10, and a winding start end of the first active material layer 142 can refer to an end of the first active material layer 142 closest to the central axis X1 of the cylindrical battery cell 6, and a winding end end of the first active material layer 142 can refer to an end of the first active material layer 142 farthest from the central axis X1 of the cylindrical battery cell 6.

[0233] The surface of the first active material layer 142 facing away from the first current collector 141 is a first surface 1421, and the first surface 1421 is wound in multiple turns along the winding direction V of the electrode assembly 10.

[0234] From the winding start end of the first active material layer 142 to the winding end end of the first active material layer 142, the first tab 14 is wound into multiple first tab winding turns 143, and the first tab winding turn 143 closest to the central axis X1 of the cylindrical battery cell 6 is the first first tab winding turn 143, and the first tab winding turns 143 from the first to the second last are all full turns, and the second last first tab winding turn 143 can be a full turn or less than a full turn, for example, 1 / 4 turn, 1 / 2 turn, or 3 / 4 turn.

[0235] For example, a plane M is made through the central axis X1 of the cylindrical battery cell 6 and the winding start end of the first active material layer 142, the plane M extends from the central axis X1 of the cylindrical battery cell 6 towards the winding start end of the first active material layer 142 until it extends to the outside of the first tab 14, the plane M intersects the first tab 14 and divides the first tab 14 into multiple first tab winding turns 143 according to the intersection points of the plane M and the first tab 14, and the part of the first tab 14 between the adjacent two intersection points forms the first tab winding turn 143 of a full turn; if the winding end end of the first active material layer 142 intersects the plane M exactly, the second last first tab winding turn 143 is also a full turn; if the winding end end of the first active material layer 142 does not intersect the plane M, the part of the first tab 14 between the outermost intersection point and the winding end end of the first active material layer 142 forms the second last first tab winding turn 143, and the second last first tab winding turn 143 is less than a full turn.

[0236] The first tab winding turns 143 are divided based on the winding start end of the first active material layer 142 and the winding end end of the first active material layer 142, so that each first tab winding turn 143 includes a first current collector winding turn 1431 and a first active material winding turn 1432.

[0237] For example, along the reverse direction of the winding direction V of the electrode assembly 10, the winding start end of the first current collector 141 exceeds the winding start end of the first active material layer 142, the portion of the first current collector 141 exceeding the first active material layer 142 does not belong to the 1st first tab winding circle 143, at this time, the winding start end of the first active material layer 142 can be the first winding start end A1.

[0238] For example, along the winding direction V of the electrode assembly 10, the winding end of the first current collector 141 exceeds the winding end of the first active material layer 142, the portion of the first current collector 141 exceeding the first active material layer 142 does not belong to the last first tab winding circle 143, at this time, the winding end of the first active material layer 142 can be the first winding end A2.

[0239] For example, the winding start end of the first current collector 141 is aligned with the winding start end of the first active material layer 142, the winding end of the first current collector 141 is aligned with the winding end of the first active material layer 142, the winding start end of the first current collector 141 and the winding start end of the first active material layer 142 jointly form the first winding start end A1, and the winding end of the first current collector 141 and the winding end of the first active material layer 142 jointly form the first winding end A2.

[0240] The portion of the first current collector 141 located in the first tab winding circle 143 is the first current collector winding circle 1431, the portion of the first active material layer 142 located in the first tab winding circle 143 is the first active material winding circle 1432, and the portion of the first surface 1421 located in the first tab winding circle 143 is the first winding surface 1433.

[0241] If the two surfaces of the first current collector 141 along the thickness direction thereof are covered with the first active material layer 142, each first tab winding circle 143 includes the first current collector winding circle 1431 and two first active material winding circles 1432, and the two first active material winding circles 1432 are respectively located on the inner side and the outer side of the first current collector 141.

[0242] If one surface of the first current collector 141 along the thickness direction thereof is covered with the first active material layer 142, each first tab winding circle 143 includes the first current collector winding circle 1431 and one first active material winding circle 1432, and the first active material winding circle 1432 is located on one side of the first current collector winding circle 1431.

[0243] The first active material winding circle 1432 is located between the first current collector winding circle 1431 and the separator 13, so that ions can be inserted into or extracted from the first active material winding circle 1432 through the separator 13, thereby realizing the charging and discharging of the battery cell.

[0244] The first active winding turn 1432 has a first winding surface 1433 facing away from the corresponding first current collecting winding turn 1431, where the "corresponding first current collecting winding turn 1431" refers to the first current collecting winding turn 1431 in the same first tab winding turn 143 as the first active winding turn 1432. The surface of the first active winding turn 1432 facing away from the first current collecting winding turn 1431 connected thereto is the first winding surface 1433, and the separator 13 is located between the second tab 15 and the first winding surface 1433. During the expansion of the electrode assembly 10, the distance between the second tab 15 and the first winding surface 1433 decreases, thereby extruding the electrolyte between the second tab 15 and the first winding surface 1433.

[0245] Referring to Figure 7 As shown in some embodiments, the second tab 15 includes a second current collector 151 and a second active material layer 152, the second active material layer 152 is connected to at least a partial region of at least one surface of the second current collector 151 along the thickness direction of the second current collector 151, and at least a portion of the second active material layer 152 is located between the second current collector 151 and the separator 13.

[0246] The second current collector 151 is covered with the second active material layer 152 on one surface thereof along the thickness direction thereof, or the second current collector 151 is covered with the second active material layer 152 on both surfaces thereof along the thickness direction thereof.

[0247] The second active material layer 152 can cover a partial region of the surface of the second current collector 151, or the second active material layer 152 can cover the entire region of the surface of the second current collector 151.

[0248] The second active material layer 152 can be directly covered on the second current collector 151, or other layer structures, such as a conductive protective layer, can be provided between the second active material layer 152 and the second current collector 151.

[0249] In some embodiments, the second tab 15 is a negative tab 12, the second tab 15 includes a second current collector 151 and a second active material layer 152, the second current collector 151 is the negative current collector 121 described above, and the second active material layer 152 is the negative active material layer 122 described above, or the second tab 15 is a positive tab 11, the second current collector 151 is the positive current collector 111 described above, and the second active material layer 152 is the positive active material layer 112 described above.

[0250] The electrode assembly 10 is in a wound structure, the second tab 15 is wound in multiple turns along the winding direction V of the electrode assembly 10, the second tab 15 is wound to form multiple second tab winding turns 153, the second current collector 151 includes a second current collector winding turn 1531 located at the second tab winding turn 153, the second active material layer 152 includes a second active material winding turn 1532 located at the second tab winding turn 153, and the second active material layer 152 has a second surface 1521 facing away from the second current collector winding turn 1531. The second tab 15 has a second winding starting end B1 and a second winding ending end B2, the second winding starting end B1 can refer to the end of the second tab 15 closest to the central axis X1 of the cylindrical battery cell 6, and the second winding ending end B2 can refer to the end of the second tab 15 farthest from the central axis X1 of the cylindrical battery cell 6.

[0251] The second current collector 151 is also wound in multiple turns along the winding direction V of the electrode assembly 10, the winding starting end of the second current collector 151 can refer to the end of the second current collector 151 closest to the central axis X1 of the cylindrical battery cell 6, and the winding ending end of the second current collector 151 can refer to the end of the second current collector 151 farthest from the central axis X1 of the cylindrical battery cell 6.

[0252] The second active material layer 152 is also wound in multiple turns along the winding direction V of the electrode assembly 10, the winding starting end of the second active material layer 152 can refer to the end of the second active material layer 152 closest to the central axis X1 of the cylindrical battery cell 6, and the winding ending end of the second active material layer 152 can refer to the end of the second active material layer 152 farthest from the central axis X1 of the cylindrical battery cell 6.

[0253] The surface of the second active material layer 152 facing away from the second current collector 151 is the second surface 1521, and the second surface 1521 is wound in multiple turns along the winding direction V of the electrode assembly 10.

[0254] From the winding starting end of the second active material layer 152 to the winding ending end of the second active material layer 152, the second tab 15 is wound into multiple second tab winding turns 153, the second tab winding turn 153 closest to the central axis X1 of the cylindrical battery cell 6 is the first second tab winding turn 153, and the second tab winding turns 153 from the first to the second last are all in a complete turn structure. The second last second tab winding turn 153 can be in a complete turn structure or less than one turn structure, for example: 1 / 4 turn, 1 / 2 turn or 3 / 4 turn. The central axis X1 of the cylindrical battery cell 6 can be parallel or close to parallel to the axial direction Z of the cylindrical battery cell 6.

[0255] For example, the center axis X1 of the over-cylindrical battery cell 6 and the winding start end of the second active material layer 152 form a plane N, the plane N extends from the center axis X1 of the over-cylindrical battery cell 6 toward the winding start end of the second active material layer 152 until extending to the outside of the second electrode tab 15, the plane N intersects the second electrode tab 15 and divides the second electrode tab 15 into a plurality of second electrode tab winding turns 153 according to the intersection points of the plane N and the second electrode tab 15, the part of the second electrode tab 15 between two adjacent intersection points forms a second electrode tab winding turn 153 of a full turn structure; if the winding end of the second active material layer 152 intersects the plane N, the last second electrode tab winding turn 153 is also of a full turn structure; if the winding end of the second active material layer 152 does not intersect the plane N, the part of the second electrode tab 15 between the outermost intersection point and the winding end of the second active material layer 152 forms the last second electrode tab winding turn 153, the last second electrode tab winding turn 153 is of a less-than-one-turn structure.

[0256] The second electrode tab winding turn 153 is divided based on the winding start end of the second active material layer 152 and the winding end of the second active material layer 152, so that each second electrode tab winding turn 153 includes a second current collector winding turn 1531 and a second active material winding turn 1532.

[0257] For example, in the direction opposite to the winding direction V of the electrode assembly 10, the winding start end of the second current collector 151 exceeds the winding start end of the second active material layer 152, the part of the second current collector 151 exceeding the second active material layer 152 does not belong to the first second electrode tab winding turn 153, at this time, the winding start end of the second active material layer 152 can be the second winding start end B1.

[0258] For example, in the winding direction V of the electrode assembly 10, the winding end of the second current collector 151 exceeds the winding end of the second active material layer 152, the part of the second current collector 151 exceeding the second active material layer 152 does not belong to the last second electrode tab winding turn 153, at this time, the winding end of the second active material layer 152 can be the second winding end B2.

[0259] For example, the winding start end of the second current collector 151 is aligned with the winding start end of the second active material layer 152, the winding end of the second current collector 151 is aligned with the winding end of the second active material layer 152, the winding start end of the second current collector 151 and the winding start end of the second active material layer 152 jointly form the second winding start end B1, and the winding end of the second current collector 151 and the winding end of the second active material layer 152 jointly form the second winding end B2.

[0260] The portion of the second current collector 151 located in the second tab winding circle 153 is a second current collector winding circle 1531, and the portion of the second active material layer 152 located in the second tab winding circle 153 is a second active material winding circle 1532. The portion of the second surface 1521 located in the second tab winding circle 153 is a second winding surface 1533.

[0261] From the inner side to the outer side of the electrode assembly 10, the first active material winding circle 1432 and the second active material winding circle 1532 are arranged alternately in sequence, and the separator 13 is wound and arranged to separate the first active material winding circle 1432 and the second active material winding circle 1532.

[0262] The second active material winding circle 1532 is located between the second current collector winding circle 1531 and the separator 13, so that ions can be inserted into or extracted from the second active material winding circle 1532 through the separator 13, thereby realizing the charging and discharging of the battery cell.

[0263] The second active material winding circle 1532 has a second winding surface 1533 facing away from the corresponding second current collector winding circle 1531, where the "corresponding second current collector winding circle 1531" refers to the second current collector winding circle 1531 located in the same second tab winding circle 153 as the second active material winding circle 1532. The surface of the second active material winding circle 1532 facing away from the second current collector winding circle 1531 connected thereto is the second winding surface 1533, and the separator 13 is located between the first winding surface 1433 and the second winding surface 1533. During the expansion of the electrode assembly 10, the distance between the first winding surface 1433 and the second winding surface 1533 decreases, thereby expelling the electrolyte between the first winding surface 1433 and the second winding surface 1533.

[0264] Referring to Figure 6 and Figure 7As shown, in some embodiments, a cylindrical battery cell 6 is provided, which includes a housing 20 and an electrode assembly 10: the diameter of the housing 20 is greater than or equal to 40 mm; the electrode assembly 10 is in a wound structure, at least part of the electrode assembly 10 is accommodated in the housing 20, the electrode assembly 10 includes a separator 13 and first and second pole pieces 14 and 15 of opposite polarity, at least part of the separator 13 is located between the first and second pole pieces 14 and 15; the first pole piece 14 includes a first current collector 141 and a first active material layer 142, the first current collector 141 is connected with the first active material layer 142 at least in part of the area of at least one surface along the thickness direction of the first current collector 141, at least part of the first active material layer 142 is located between the first current collector 141 and the separator 13; the second pole piece 15 includes a second current collector 151 and a second active material layer 152, the second current collector 151 is connected with the second active material layer 152 at least in part of the area of at least one surface along the thickness direction of the second current collector 151, at least part of the second active material layer 152 is located between the second current collector 151 and the separator 13; m gaps are formed between the first and second active material layers 142 and 152, m ≥ 30, m is a natural number; the innermost one of the gap winding turns is the first gap winding turn; the average value of the radial dimension of the m-13th to m-5th gap winding turns is greater than the average value of the radial dimension of the 5th to 13th gap winding turns.

[0265] For example, m is 30, 40, 50, 60, 70, 80, 90, 100, 150 or 200.

[0266] For example, referring to Figure 6 As shown, after the first and second pole pieces 14 and 15 are wound, two gaps are formed between the first and second active material layers 142 and 152, which can be spaces located between the first and second pole pieces 14 and 15 and not filled by the separator 13.

[0267] The two gaps are divided into a first gap and a second gap, the first gap is wound to form a first number of gap winding turns G, and the second gap is wound to form a second number of gap winding turns G, the first number of gap winding turns G of the first gap and the second number of gap winding turns G of the second gap are arranged alternately from the inside to the outside of the electrode assembly 10, that is, from the center to the periphery of the electrode assembly 10, the first number of gap winding turns G of the first gap and the second number of gap winding turns G of the second gap are arranged alternately.

[0268] For example, the first and second gaps can be formed in various ways.

[0269] For example, when winding the first pole piece 14, the separator 13 and the second pole piece 15, the tightness of the electrode assembly 10 after being wound and formed is adjusted by controlling the tension or other parameters of the three, and then the first and second gaps of a predetermined size are formed.

[0270] During the cycling of the cylindrical battery cell 6, the gap winding turns G can provide space for the expansion of the electrode assembly 10, reduce the pressure between the first active material layer 142 and the second active material layer 152, thereby reducing the amount of electrolyte squeezed out between the first tab 14 and the second tab 15. In combination with the grooves 144, the wettability of the first tab 14 and the second tab 15 can be effectively improved, the cycling performance of the cylindrical battery cell 6 can be improved, in addition, the first gap and the second gap can reduce the expansion amount of the electrode assembly 10, thereby reducing the squeezing effect on the shell 20, reducing the risk of deformation and cracking of the shell 20, and improving the reliability of the cylindrical battery cell 6.

[0271] From the inside to the outside of the electrode assembly 10, the m gap winding turns G are sequentially arranged. The first gap winding turn G is closest to the central axis X1 of the cylindrical battery cell 6 compared with other gap winding turns G.

[0272] For example, the first gap winding turn G is formed between the first tab winding turn 143 and the first tab winding turn 143, the second gap winding turn G is formed between the first tab winding turn 143 and the second tab winding turn 153, the third gap winding turn G is formed between the second tab winding turn 153 and the third tab winding turn 143, and so on. Finally, the m gap winding turns are formed.

[0273] In some examples, the average value of the radial dimension of the 5th to 13th gap winding turns G can be measured in the following manner:

[0274] Discharge the cylindrical battery cell 6 to the lower limit cut-off voltage (for example, 2.5V);

[0275] Using the CT (Computed Tomography, Computed Tomography) technology, the cross section of the cylindrical battery cell 6 is obtained by X-ray, which is perpendicular to the central axis X1 of the cylindrical battery cell 6 and intersects the first active material layer 142 and the second active material layer 152, and the cross section shows the first tab 14, the second tab 15 and the separator 13.

[0276] Based on the image and the virtual straight line X2, the first intersection point of the outer surface of the third tab winding turn 143 and the virtual straight line X2 is obtained in the direction away from the center of the cross section and parallel to the virtual straight line X2, the second intersection point of the inner surface of the seventh tab winding turn 153 and the virtual straight line X2 is obtained, and the distance D1 between the first intersection point and the second intersection point is measured.

[0277] Disassemble the cylindrical battery cell 6, and unfold the first tab 14, the second tab 15 and the separator 13;

[0278] 50 thickness values of the first pole pieces 14 at 50 positions on the surface of the first active material layer 142 are measured, and then an average value of the 50 thickness values is calculated, which can be the thickness T1 of the first pole piece 14;

[0279] 50 thickness values of the second pole pieces 15 at 50 positions on the surface of the second active material layer 152 are measured, and then an average value of the 50 thickness values is calculated, which can be the thickness T2 of the second pole piece 15;

[0280] 50 thickness values of the separators 13 at 50 positions on the separators 13 are measured, and then an average value of the 50 thickness values is calculated, which can be the thickness T3 of the separators 13.

[0281] The outer surface of the 3rd first pole piece winding ring 143 and the inner surface of the 7th second pole piece winding ring 153 are provided with 4 first pole piece winding rings 143, 4 second pole piece winding rings 153 and 9 layers of separators 13; the outer surface of the 3rd first pole piece winding ring 143 and the inner surface of the 7th second pole piece winding ring 153 form 9 gap winding rings G, and the average value W1 of the radial dimensions of the 5th to 13th gap winding rings G is (D1-4×T1-4×T2-9×T3) / 9.

[0282] Similarly, based on the image and the virtual straight line X2, the third intersection point of the inner surface of the 3rd last second pole piece winding ring 153 and the virtual straight line X2 is obtained in a direction away from the center of the section and parallel to the virtual straight line X2, the fourth intersection point of the outer surface of the 8th last first pole piece winding ring 143 and the virtual straight line X2 is obtained, and the distance D2 between the third intersection point and the fourth intersection point is measured.

[0283] The inner surface of the 3rd last second pole piece winding ring 153 and the outer surface of the 8th last first pole piece winding ring 143 are provided with 4 first pole piece winding rings 143, 4 second pole piece winding rings 153 and 9 layers of separators 13; the inner surface of the 3rd last second pole piece winding ring 153 and the outer surface of the 8th last first pole piece winding ring 143 form 9 gap winding rings G, and the average value W2 of the radial dimensions of the m-13th to m-5th gap winding rings G is (D2-4×T1-4×T2-9×T3) / 9.

[0284] Wherein, W1 < W2.

[0285] During the cycle of the cylindrical battery cell 6, the expansion of the electrode assembly 10 gradually accumulates from inside to outside in the radial direction, and the expansion accumulation force of the outer side of the electrode assembly 10 is large. The m-13th to m-5th gap winding turns G are arranged outward compared to the 5th to 13th gap winding turns G, and the average value of the radial dimension of the m-13th to m-5th gap winding turns G is greater than the average value of the radial dimension of the 5th to 9th gap winding turns G. The average value of the radial dimension of the m-13th to m-5th gap winding turns G is large, so that the gap winding turns G on the outer side of the electrode assembly 10 have a larger radial dimension, which can provide more expansion space for the outer side of the electrode assembly 10, absorb the accumulated expansion amount of the electrode assembly 10, and effectively reduce the acting force between the electrode assembly 10 and the shell 20, reduce the deformation amount of the shell 20, reduce the risk of cracking of the shell 20, and improve the reliability of the cylindrical battery cell 6. In addition, the gap winding turns G on the outer side of the electrode assembly 10 have a larger radial dimension, which is also beneficial to reducing the amount of electrolyte extruded from the outer side of the electrode assembly 10, and is beneficial to improving the cycle performance of the cylindrical battery cell 6. The average value of the radial dimension of the 5th to 9th gap winding turns G is small, so that the gap winding turns G on the inner side of the electrode assembly 10 have a larger radial dimension, which can increase the compactness of the structure on the inner side of the electrode assembly 10, and is beneficial to improving the energy density of the cylindrical battery cell 6.

[0286] In some embodiments, the gap winding turns G include a first gap sub-turn G1 and a second gap sub-turn G2, the first gap sub-turn G1 is located between the first active material layer 142 and the separator 13, and the second gap sub-turn G2 is located between the second active material layer 152 and the separator 13.

[0287] As an example, the radial dimension of the first gap sub-turn G1 is W3, and the radial dimension of the second gap sub-turn G2 is W4. The radial dimension W of the gap winding turns G is W3+W4.

[0288] The first gap sub-turn G1 and the second gap sub-turn G2 can both provide space for the expansion of the electrode assembly 10, thereby reducing the extrusion effect on the shell 20, reducing the risk of deformation and cracking of the shell 20, and improving the reliability of the cylindrical battery cell 6.

[0289] In some embodiments, the radial dimension of the 1st gap winding turn G is smaller than the radial dimension of the mth gap winding turn G.

[0290] By adopting the technical scheme of the embodiment, the radial dimension of the mth gap winding circle G is large, so that there is a large gap space between the first active material layer 142 and the second active material layer 152 on the outside of the electrode assembly 10, which can provide more expansion space for the outside of the electrode assembly 10, absorb the accumulated expansion amount of the electrode assembly 10, and effectively reduce the acting force between the electrode assembly 10 and the shell 20, reduce the deformation amount of the shell 20, reduce the risk of cracking of the shell 20, and improve the reliability. In addition, the larger gap between the first active material layer 142 and the second active material layer 152 on the outside of the electrode assembly 10 is also beneficial to reducing the amount of electrolyte squeezed out of the outside of the electrode assembly 10, and is beneficial to improving the cycle performance of the cylindrical battery monomer 6. The radial dimension of the first gap winding circle G is small, so that there is a small gap between the first active material layer 142 and the second active material layer 152 on the inside of the electrode assembly 10, which can increase the compactness of the inside of the electrode assembly 10, and is beneficial to improving the energy density of the cylindrical battery monomer 6.

[0291] In some embodiments, the m gap winding circles G are divided into j groups of gap winding circles G in the order of the inside to the outside of the electrode assembly 10; the innermost group of gap winding circles G is the first group of gap winding circles G, and each group of gap winding circles G in the first group to the j-1 group includes 9 gap winding circles G, 1≤m-9*(j-1)≤9, and j is a natural number; the average of the radial dimensions of the first group to the j-1 group of gap winding circles G is incrementally arranged.

[0292] The m gap winding circles G are divided into j groups from the inside to the outside of the electrode assembly 10, that is, the m gap winding circles G are divided into j groups of gap winding circles G from the center to the periphery of the electrode assembly 10.

[0293] The group of gap winding circles G closest to the central axis X1 of the cylindrical battery monomer 6 is the first group of gap winding circles G. The first group to the j-1 group of gap winding circles G each include 9 gap winding circles G, and the number of the jth group of gap winding circles G is 1, 2, 3, 4, 5, 6, 7, 8, or 9.

[0294] For example, the first to ninth gap winding circles G form the first group of gap winding circles G, the tenth to eighteenth gap winding circles G form the second group of gap winding circles G, the nineteenth to twenty-seventh gap winding circles G form the third group of gap winding circles G, and so on.

[0295] For example, the average of the radial dimensions of the first group of gap winding circles G can be measured in the following manner, and the average of the radial dimensions of the other groups of gap winding circles G can also be obtained in the following measurement manner.

[0296] Discharge the cylindrical battery monomer 6 to the lower limit cut-off voltage (for example, 2.5V);

[0297] An image of the cross section of the cylindrical battery cell 6 is acquired using the X-ray;

[0298] Based on the image, a virtual straight line X2 is set, which can pass through the center of the cross section (the virtual straight line X2 intersects with the central axis X1);

[0299] Based on the image and the virtual straight line X2, the fifth intersection point of the outer surface of the first 1st first electrode tab winding 143 and the virtual straight line X2, the sixth intersection point of the inner surface of the 5th second electrode tab winding 153 and the virtual straight line X2 are acquired along the direction away from the center of the cross section and parallel to the virtual straight line X2, and the distance D3 between the fifth intersection point and the sixth intersection point is measured;

[0300] There are 4 first electrode tab windings 143, 4 second electrode tab windings 153 and 9 separators 13 between the outer surface of the first 1st first electrode tab winding 143 and the inner surface of the 5th second electrode tab winding 153, and 9 gap windings G are formed between the outer surface of the first 1st first electrode tab winding 143 and the inner surface of the 5th second electrode tab winding 153, and the average value W5 of the radial dimensions of the first group of gap windings G is (D3-4xT1-4xT2-9xT3) / 9.

[0301] By adopting the technical scheme of the embodiment, the average values of the radial dimensions of the first group to the j-1th group of gap windings G are set to increase, the radial dimensions of the gap windings G of the electrode assembly 10 increase from the inside to the outside, the radial dimensions of the gap windings G of the electrode assembly 10 increase, and the radial dimensions of the gap windings G on the outside of the electrode assembly 10 are large, which can provide more expansion space for the electrode assembly 10, absorb the accumulated expansion amount of the electrode assembly 10, and further reduce the acting force between the electrode assembly 10 and the shell 20, reduce the deformation amount of the shell 20, reduce the risk of cracking of the shell 20, and improve the reliability. In addition, the radial dimensions of the gap windings G on the inside of the electrode assembly 10 are small, which can effectively increase the compactness of the structure on the inside of the electrode assembly 10, and is beneficial to improve the energy density of the cylindrical battery cell 6.

[0302] In some embodiments, the first electrode tab 14 is wound to form a plurality of first electrode tab windings 143, the first current collector 141 includes a first current collector winding 1431 located at the first electrode tab winding 143, the first active material layer 142 includes a first active winding 1432 located at the first electrode tab winding 143, and the first active winding 1432 has a first winding surface 1433 facing away from the corresponding first current collector winding 1431; the first winding surface 1433 of at least one first electrode tab winding 143 is provided with a groove 144.

[0303] The first winding surface 1433 of the at least one first pole piece winding ring 143 is provided with at least one groove 144, and for example, the number of the first pole piece winding rings 143 provided with the groove 144 is one or more. The first winding surface 1433 can be provided with one or more grooves 144. The cross-sectional shape of the groove 144 can be rectangular, trapezoidal, circular arc, or inverted triangular, etc. The groove 144 can be machined on the surface of the first active winding ring 1432 by means of laser or mechanical cutting, etc.

[0304] For example, one or more first pole piece winding rings 143 close to the inner side of the electrode assembly 10 are not provided with the groove 144; or, one or more first pole piece winding rings 143 close to the outer side of the electrode assembly 10 are not provided with the groove 144, or, one or more first pole piece winding rings 143 located at the middle position of the electrode assembly 10 are not provided with the groove 144.

[0305] For example, all the first pole piece winding rings 143 are provided with the groove 144.

[0306] By adopting the technical scheme of the embodiment, in the charging and discharging process of the battery monomer, ions pass through the separator 13 and reciprocate between the second pole piece 15 and the first active winding ring 1432 of the first pole piece winding ring 143 through the electrolyte to embed and extract, so as to realize the transmission of electric energy of the cylindrical battery monomer 6. At the same time, in the charging and discharging process of the battery monomer, the electrode assembly 10 expands, the distance between the second pole piece 15 and the first winding surface 1433 of the first pole piece winding ring 143 decreases, and the electrolyte located between the second pole piece 15 and the first winding surface 1433 is squeezed out. The first winding surface 1433 of the at least one first pole piece winding ring 143 is provided with at least one groove 144. On the one hand, the electrolyte can flow into the groove 144 for storage, the stored electrolyte can soak the first pole piece 14 and provide a transmission path for ions, reduce the transmission resistance of ions, and improve the cycle performance of the cylindrical battery monomer 6; on the other hand, the groove 144 can also provide a channel for the backflow of the electrolyte, reduce the difficulty of the backflow of the electrolyte, reduce the transmission resistance of the ions, improve the soaking effect of the first pole piece 14, and also help to improve the cycle performance of the cylindrical battery monomer 6.

[0307] In some embodiments, the second winding surface 1533 of the at least one second pole piece winding ring 153 is provided with at least one groove 144, and for example, the number of the second pole piece winding rings 153 provided with the groove 144 is one or more. The second winding surface 1533 can be provided with one or more grooves 144.

[0308] For example, one or more of the second tab winding turns 153 near the inner side of the electrode assembly 10 are not provided with the groove 144; or, one or more of the second tab winding turns 153 near the outer side of the electrode assembly 10 are not provided with the groove 144; or, one or more of the second tab winding turns 153 located at the middle of the electrode assembly 10 are not provided with the groove 144.

[0309] For example, all of the second tab winding turns 153 are provided with the groove 144.

[0310] The first winding surface 1433 and the second winding surface 1533 are oppositely arranged, and the first winding surface 1433 and the second winding surface 1533 are both provided with the groove 144. The groove 144 of the first active winding turn 1432 and the groove 144 of the second active winding turn 1532 can both store electrolyte and guide the electrolyte backflow. The first active winding turn 1432 and the second active winding turn 1532 have good wetting effect, which is conducive to improving the cycle performance of the cylindrical battery monomer 6.

[0311] The groove 144 structure of the second winding surface 1533 can be the same as or different from that of the first winding surface 1433. For the convenience of description, the first winding surface 1433 is provided with the groove 144 as an example.

[0312] Referring to Figure 9 In some embodiments, the number of the groove 144 is multiple, and the multiple grooves 144 include at least one first groove 1441. The first groove 1441 extends along the axial direction Z of the cylindrical battery monomer 6.

[0313] The first tab winding turn 143 is provided with multiple grooves 144. Among the multiple grooves 144, at least one groove 144 is referred to as the first groove 1441.

[0314] The first groove 1441 extends along the axial direction Z of the cylindrical battery monomer 6. It can be understood that the first groove 1441 extends from one side of the first surface 1421 to the other side along the axial direction Z of the cylindrical battery monomer 6, and it is not required that the first groove 1441 completely extends in the first direction.

[0315] In some examples, the first groove 1441 can extend along the first square straight line, or extend from one side of the first surface 1421 to the other side in a direction inclined relative to the axial direction Z of the cylindrical battery monomer 6, or extend from one side of the first surface 1421 to the other side in an arc shape or a bending shape.

[0316] Referring to Figure 10 and Figure 11 As shown in the drawings, the first groove 1441 can be arranged to be deviated from one end of the first active winding turn 1432 or located at the middle of the first active winding turn 1432 in the axial direction Z of the cylindrical battery monomer 6.

[0317] In the cylindrical battery cell 6, the electrode assembly 10 expands, the electrolyte is squeezed out of the electrode assembly 10 from both ends of the cylindrical battery cell 6 in the axial direction Z, the first grooves 1441 are formed in the axial direction Z of the cylindrical battery cell 6, and the electrolyte squeezed out of the electrode assembly 10 can be better guided to flow back, the flow back rate of the electrolyte is effectively improved, the impregnation effect of the first electrode sheet 14 is improved, and the cycle performance of the cylindrical battery cell 6 is improved.

[0318] Referring to Figure 12 In some embodiments, as shown in the drawings, the plurality of grooves 144 can further include second grooves 1444, and the second grooves 1444 are arranged intersecting the first grooves 1441, and the plurality of first grooves 1441 and the plurality of second grooves 1444 form a grid structure.

[0319] Referring to Figure 12 and Figure 13 In some embodiments, as shown in the drawings, the grooves 144 can be straight structures, and the grooves 144 can also be arranged obliquely with respect to the axial direction Z of the cylindrical battery cell 6.

[0320] Referring to Figure 14 In some embodiments, as shown in the drawings, the grooves 144 can also be wave structures, for example, the grooves 144 extend in a wave shape along the winding direction V of the electrode assembly 10.

[0321] In some embodiments, the grooves 144 can also extend along the winding direction V of the electrode assembly 10, on the one hand, the grooves 144 can store electrolyte, and on the other hand, the grooves 144 can also guide the electrolyte to flow back along the winding direction V of the electrode assembly 10, improve the uniformity of the distribution of the electrolyte in the winding direction V of the electrode assembly 10, and improve the impregnation effect of the first electrode sheet 14. Of course, in other embodiments, the grooves 144 can also have other structures.

[0322] Referring to Figure 15 In some embodiments, as shown in the drawings, the number of the first grooves 1441 is a plurality, and the plurality of first grooves 1441 are arranged at intervals along the winding direction V of the electrode assembly 10, and the distance between the adjacent two first grooves 1441 is arranged to be increased.

[0323] The plurality of first grooves 1441 are arranged at non-constant intervals, for example, the distance between the adjacent two first grooves 1441 along the winding direction V of the electrode assembly 10 is increased in steps, so that the distance between the adjacent two first grooves 1441 in some sections of the first electrode sheet 14 is the same.

[0324] For example, the distance between the adjacent two first grooves 1441 along the winding direction V of the electrode assembly 10 is sequentially increased, so that the distance between the adjacent two first grooves 1441 in the entire first electrode sheet 14 is different.

[0325] Along the winding direction V of the electrode assembly 10, a plurality of first grooves 1441 are spaced apart, and the distance between two adjacent first grooves 1441 is increased, such that the distance between two adjacent first grooves 1441 near the inner side of the electrode assembly 10 is smaller than the distance between two adjacent first grooves 1441 near the outer side of the electrode assembly 10.

[0326] By adopting the technical solution of this embodiment, after the first electrode 14 is wound along the winding direction V of the electrode assembly 10, the number of first grooves 1441 near the inner side of the electrode assembly 10 is large, and the number of first grooves 1441 near the outer side of the electrode assembly 10 is small. This is beneficial to improve the electrolyte reflux effect inside the electrode assembly 10 and improve the wetting effect inside the electrode assembly 10, thereby improving the cycle performance of the cylindrical battery cell 6.

[0327] In particular, when the gap between the first electrode 14 and the second electrode 15 near the inner side of the electrode assembly 10 is small, the number of first grooves 1441 near the inner side of the electrode assembly 10 is large, which can effectively improve the wetting effect on the inner side of the electrode assembly 10, thereby effectively improving the cycle performance of the cylindrical battery cell 6.

[0328] Of course, in other examples, multiple first grooves 1441 can also be set at equal intervals.

[0329] See Figure 15 and Figure 16 As shown, in some embodiments, the thickness of the first active material layer 142 is t, and the groove depth of the first groove 1441 is h, wherein 0.05≤h / t≤0.84.

[0330] In some examples, the first groove 1441 forms a slot 144b on the first surface 1421, and the area within a preset distance of the first surface 1421 from the slot 144b is the measurement area 1421c. The thickness of the first active material layer 142 at the measurement area 1421c is equal to the thickness t of the first active material layer 142, and the preset distance is 5mm.

[0331] The measurement area 1421c can refer to the area enclosed by the slot 144b and the outer edge 1421d of the measurement area 1421c. The outer edge 1421d is arranged around the slot 144b, and the outer edge 1421d has the same shape as the slot 144b. The distance between the outer edge 1421d and the slot 144b is 5mm.

[0332] In some examples, the groove depth of the first groove 1441 does not change along the axial direction Z of the cylindrical battery cell 6, and the groove depth of the first groove 1441 at any position is equal to the groove depth h of the first groove 1441.

[0333] In some examples, the groove depth of the first groove 1441 varies along the axial direction Z of the cylindrical battery cell 6, and the maximum groove depth of the first groove 1441 is equal to the groove depth h of the first groove 1441. For example, the groove depth of the end portion of the first groove 1441 is less than the groove depth of the middle portion of the first groove 1441 along the axial direction Z of the cylindrical battery cell 6, and the groove depth of the middle portion of the first groove 1441 is equal to the groove depth h of the first groove 1441.

[0334] In some examples, the value of h / t can be 0.05, 0.84, or any value between 0.05 and 0.84. For example, but not limited to, the value of h / t can be 0.05, 0.08, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.81, 0.84.

[0335] The design of h / t≥0.05 enables the first groove 1441 to store electrolyte and guide the electrolyte backflow, improves the wettability of the first electrode tab 14, and improves the cycle performance of the cylindrical battery cell 6. The design of h / t≤0.84 is that the first groove 1441 does not penetrate the first active material layer 142, and the first current collector 141 is not exposed, which reduces the risk of direct reaction between the first current collector 141 and ions. In addition, compared with the first groove 1441 penetrating the first active material layer 142, the first active material layer 142 removes less active material, which is beneficial to improve the active material capacity of the first electrode tab 14 and reduce the risk of performance degradation of the cylindrical battery cell 6 caused by insufficient active material capacity of the first electrode tab 14. Therefore, the cycle performance and the performance of the cylindrical battery cell 6 can be considered.

[0336] In particular, the first electrode tab 14 is the negative electrode tab 12, and the first groove 1441 does not penetrate the negative active material layer 122, so that the ions do not directly react with the first current collector 141, reducing the problem of lithium precipitation of the cylindrical battery cell 6. In addition, the negative active material layer 122 removes less negative active material, which is beneficial to reduce the risk of lithium precipitation caused by insufficient negative active material and improve the performance of the cylindrical battery cell 6.

[0337] In some embodiments, 0.08≤h / t≤0.8, which can better consider the cycle performance and the performance of the cylindrical battery cell 6.

[0338] In some embodiments, 0.1≤h / t≤0.5, which can better consider the cycle performance and the performance of the cylindrical battery cell 6.

[0339] In some embodiments, the groove depth of the first groove 1441 is h, and 0μm<h≤50μm.

[0340] In some examples, the value of h can be 50 μm or any value between 0 and 50 μm, for example, but not limited to, 0 μm, 2 μm, 4 μm, 6 μm, 10 μm, 20 μm, 30 μm, 40 μm, 50 μm.

[0341] The design of 0 μm < h ≤ 50 μm makes the groove depth h of the first groove 1441 reasonable, so that the first groove 1441 can store electrolyte and guide the electrolyte backflow, improve the impregnation effect of the first tab 14, and improve the cycle performance of the cylindrical battery monomer 6. In addition, the active material removed by the first active material layer 142 is less, which is beneficial to improve the active material capacity of the first tab 14, and can also reduce the risk of degradation of the use performance of the cylindrical battery monomer 6 caused by insufficient active material capacity of the first tab 14. Therefore, the cycle performance and use performance of the cylindrical battery monomer 6 can be considered.

[0342] In some embodiments, 6 μm ≤ h ≤ 30 μm, which can better consider the cycle performance and use performance of the cylindrical battery monomer 6.

[0343] In some embodiments, the groove width of the first groove 1441 is w, wherein 30 μm ≤ w ≤ 1000 μm.

[0344] In some examples, along the axial direction Z of the cylindrical battery monomer 6, the groove width of the first groove 1441 does not change, and the groove width of the first groove 1441 at any position is equal to the groove width w of the first groove 1441.

[0345] In some examples, along the axial direction Z of the cylindrical battery monomer 6, the groove width of the first groove 1441 changes, and the maximum groove width of the first groove 1441 is equal to the groove width w of the first groove 1441. For example, along the axial direction Z of the cylindrical battery monomer 6, the groove width of the end of the first groove 1441 is less than the groove width of the middle of the first groove 1441, and the groove width of the middle of the first groove 1441 is equal to the groove width w of the first groove 1441.

[0346] In some examples, the value of w can be 30 μm, 1000 μm, or any value between 30 μm and 1000 μm, for example, but not limited to, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 100 μm, 110 μm, 140 μm, 180 μm, 200 μm, 300 μm, 400 μm, 500 μm, 600 μm, 800 μm, 1000 μm.

[0347] The design of w≥30 μm enables the first groove 1441 to store electrolyte and guide the electrolyte backflow, improves the impregnation effect of the first tab 14, improves the cycle performance of the cylindrical battery cell 6, and facilitates the processing and manufacturing of the first groove 1441; the design of w≤1000 μm reduces the active material removed from the first active material layer 142, is conducive to improving the active material capacity of the first tab 14, and can also reduce the risk of degradation of the use performance of the cylindrical battery cell 6 due to insufficient active material capacity of the first tab 14; in addition, the first groove 1441 is not easily flattened during the hot pressing process of the first tab 14, and the shape of the first groove 1441 can be stably maintained. Therefore, the cycle performance and use performance of the cylindrical battery cell 6 can be considered.

[0348] In some embodiments, 50 μm≤w≤500 μm, which can better consider the cycle performance and use performance of the cylindrical battery cell 6.

[0349] In some embodiments, 80 μm≤w≤120 μm, which can better consider the cycle performance and use performance of the cylindrical battery cell 6.

[0350] In some embodiments, the first groove 1441 has a groove width w and a groove depth h, and 0.05≤h / w≤1.

[0351] In some examples, the value of h / w can be 0.05, 1, or any value between 0.05 and 1, for example, but not limited to, 0.05, 0.08, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.

[0352] In the case of a certain h, the design of h / w≥0.05 prevents the groove width w of the first groove 1441 from being too large, so that the first groove 1441 is not easily flattened during the hot pressing process of the first tab 14, and the shape of the first groove 1441 can be stably maintained; the design of h / w≤1 enables the electrolyte to have a relatively wide channel during backflow, which is conducive to the backflow of the electrolyte and improves the cycle performance of the cylindrical battery cell 6; therefore, the processing and manufacturing of the first groove 1441 and the cycle performance of the cylindrical battery cell 6 can be considered.

[0353] In some embodiments, 0.1≤h / w≤0.5, which can better consider the processing and manufacturing of the first groove 1441 and the cycle performance of the battery cell 6.

[0354] On the basis of 0 μm < h < 50 μm, the design of 0.05 < h / w < 1 makes the first groove 1441 have a proper width and depth, can form a capillary channel and guide the electrolyte accumulated at the bottom to the electrode assembly 10 by capillary action, so as to effectively improve the wetting effect of the electrode assembly 10 and improve the cycle performance of the battery monomer 6.

[0355] Referring to Figure 15 and Figure 16 , in some embodiments, along the axial direction Z of the cylindrical battery monomer 6, the size of the first active material layer 142 is L, the groove depth of the first groove 1441 is h, and 5*10 -5 < h / L < 5*10 -4 .

[0356] In some examples, the value of h / L can be 5*10 -5 , 5*10 -4 or any value between 5*10 -5 ~5*10 -4 , for example, but not limited to, 5*10 -5 , 7*10 -5 , 9*10 -5 , 1*10 -4 , 2*10 -4 , 3*10 -4 , 4*10 -4 , 5*10 -4 .

[0357] In the case of a certain L, the design of h / L > 5*10 -5 , the groove depth h of the first groove 1441 can make the electrolyte flow back quickly and improve the wetting effect of the first electrode sheet 14; in addition, the design of h / L < 5*10 -4 , can reduce the risk of excessive loss of active material of the first electrode sheet 14 due to the excessive groove depth h of the first groove 1441 and the exposure of the first current collector 141, so that the capacity, cycle performance and use reliability of the cylindrical battery monomer 6 can be considered.

[0358] Referring to Figure 15 and Figure 16 , in some embodiments, along the axial direction Z of the cylindrical battery monomer 6, the size of the first active material layer 142 is L, the groove depth of the first groove 1441 is h, wherein L > 60 mm and h > 6 μm.

[0359] In some examples, the value of L can be 60mm or any value greater than 60mm. For example, the value of L can be, but is not limited to, 60mm, 70mm, 80mm, 90mm, 100mm, 110mm, 120mm, 130mm, 150mm, 200mm, 300mm, and 400mm.

[0360] In some examples, the value of h can be 6 μm or any value greater than 6 μm. For example, the value of h can be, but is not limited to, 6 μm, 10 μm, 20 μm, 30 μm, 40 μm, and 50 μm.

[0361] By adopting the technical solution of this embodiment, for cylindrical battery cells 6 with L≥60mm and h≥6μm, the first groove 1441 can store more electrolyte and guide electrolyte reflux better, which can effectively improve the wetting effect of the first electrode 14 and improve the cycle performance of the cylindrical battery cell 6.

[0362] See Figure 15 and Figure 16 As shown, in some embodiments, along the axial direction Z of the cylindrical battery cell 6, the size of the first groove 1441 is l, and the size of the first active material layer 142 is L, 0.8≤l / L≤1; optionally, 0.9≤l / L≤0.98.

[0363] In some examples, the value of l / L can be 0.8, 1, or any value between 0.8 and 1. For example, the value of l / L can be, but is not limited to, 0.8, 0.85, 0.9, 0.95, 0.98, 0.99, and 1.

[0364] The design of 0.8≤l / L≤1 ensures that the size l of the first groove 1441 and the size L of the first active material layer 142 are not much different or the same along the axial direction Z of the cylindrical battery cell 6. The two ends of the first groove 1441 are close to the two ends of the first active material layer 142, which allows the electrolyte squeezed out from the two ends of the electrode assembly 10 to flow back quickly through the first groove 1441, effectively improving the wetting effect of the first electrode 14 and improving the cycle performance of the cylindrical battery cell 6.

[0365] See Figure 15 and Figure 16 As shown, in some embodiments, 0.9 ≤ l / L ≤ 0.98 can better improve the cycle performance of the cylindrical battery cell 6.

[0366] In some embodiments, 60mm ≤ L ≤ 330mm.

[0367] In some examples, the value of L can be 60mm, 330mm, or any value between 60mm and 330mm. For example, the value of L can be, but is not limited to, 60mm, 70mm, 80mm, 90mm, 100mm, 110mm, 100mm, 150mm, 200mm, 250mm, 300mm, and 330mm.

[0368] By adopting the technical solution of this embodiment, with a design of 60mm≤L≤330mm, the size of the first active material layer 142 is larger along the axial direction Z of the cylindrical battery cell 6, and the first active material layer 142 can accommodate more active material, thereby increasing the capacity of the cylindrical battery cell 6. However, along the axial direction Z of the cylindrical battery cell 6, the distance for the extruded electrolyte to flow back to the middle of the first active material layer 142 is long, increasing the difficulty of the extruded electrolyte flowing back to the middle of the first active material layer 142. However, combined with the design of 0.8≤l / L≤1, the extruded electrolyte can quickly flow back to the middle of the first active material layer 142 through the first groove 1441, which is beneficial to improving the wetting effect of the first electrode 14 and improving the cycle performance of the cylindrical battery cell 6. Therefore, the capacity and cycle performance of the cylindrical battery cell 6 can be balanced.

[0369] In some embodiments, 70mm≤L≤200mm can better balance the capacity and cycle performance of the cylindrical battery cell 6.

[0370] See Figure 17 and Figure 18 As shown, in some embodiments, the first groove 1441 includes a first groove segment 1442 and a second groove segment 1443 that are connected to each other. The first groove segment 1442 is connected to at least one end of the second groove segment 1443 along the axial direction Z of the cylindrical battery cell 6. The groove depth of the first groove segment 1442 is greater than the groove depth of the second groove segment 1443, and / or the groove width of the first groove segment 1442 is greater than the groove width of the second groove segment 1443.

[0371] Along the axial direction Z of the cylindrical battery cell 6, one end of the first groove segment 1442 is connected to the second groove segment 1443, or both ends of the first groove segment 1442 are connected to the second groove segment 1443.

[0372] For example, the first groove 1441 is divided into three segments along the axial direction Z of the cylindrical battery cell 6. The middle segment is the first groove segment 1442, and the two ends are the second groove segments 1443. The first groove segment 1442 and the second groove 1444 are divided based on the groove depth change point of the first groove 1441 or the groove width change point of the first groove segment 1442.

[0373] The groove depth of the first groove section 1442 is greater than the groove depth of the second groove section 1443. For example, the first groove section 1442 and the second groove section 1443 are both of equal depth structure, and the groove bottom surface of the first groove section 1442 and the groove bottom surface of the second groove section 1443 form a stepped structure.

[0374] The groove width of the first groove section 1442 is greater than the groove width of the second groove section 1443. For example, the first groove section 1442 and the second groove section 1443 are both of equal width structure, and the groove side surface of the first groove section 1442 and the groove side surface of the second groove section 1443 form a stepped structure.

[0375] In some examples, the first groove 1441 includes the first groove section 1442 and the second groove section 1443 connected in communication, the first groove section 1442 is connected with the second groove section 1443 at least at one end along the axial direction Z of the cylindrical battery cell 6, the groove depth of the first groove section 1442 is greater than the groove depth of the second groove section 1443, so that the electrolyte is more prone to generate a siphon effect at the second groove section 1443, which is more conducive to the rapid return flow of the electrolyte, improves the impregnation effect of the first pole piece 14, and improves the cycle performance of the cylindrical battery cell 6.

[0376] In some examples, the first groove 1441 includes the first groove section 1442 and the second groove section 1443 connected in communication, the first groove section 1442 is connected with the second groove section 1443 at least at one end along the axial direction Z of the cylindrical battery cell 6, the groove width of the first groove section 1442 is greater than the groove width of the second groove section 1443, so that the electrolyte is more prone to generate a siphon effect at the second groove section 1443, which is more conducive to the rapid return flow of the electrolyte, improves the impregnation effect of the first pole piece 14, and improves the cycle performance of the cylindrical battery cell 6.

[0377] In some examples, the first groove 1441 includes the first groove section 1442 and the second groove section 1443 connected in communication, the first groove section 1442 is connected with the second groove section 1443 at least at one end along the axial direction Z of the cylindrical battery cell 6, the groove depth of the first groove section 1442 is greater than the groove depth of the second groove section 1443, and the groove width of the first groove section 1442 is greater than the groove width of the second groove section 1443, so that the electrolyte is more prone to generate a siphon effect at the second groove section 1443, which is more conducive to the rapid return flow of the electrolyte, improves the impregnation effect of the first pole piece 14, and improves the cycle performance of the cylindrical battery cell 6.

[0378] In some embodiments, along the direction in which the first groove section 1442 points to the second groove section 1443, the groove depth of the second groove section 1443 is arranged to decrease from the first groove section 1442; and / or, along the direction in which the first groove section 1442 points to the second groove section 1443, the groove width of the second groove section 1443 is arranged to decrease from the first groove section 1442.

[0379] For example, the first groove segment 1442 is an equal-depth structure, the second groove segment 1443 is a non-equal-depth structure, the groove depth of the second groove segment 1443 is arranged to decrease from the first groove segment 1442, and the groove depth of the second groove segment 1443 can decrease in steps or slowly decrease to form a smooth structure and reduce stress concentration at the second groove segment 1443.

[0380] For example, the first groove segment 1442 is an equal-width structure, the second groove segment 1443 is a non-equal-width structure, the groove width of the second groove segment 1443 is arranged to decrease from the first groove segment 1442, and the groove width of the second groove segment 1443 can decrease in steps or slowly decrease to form a smooth structure and reduce stress concentration at the second groove segment 1443.

[0381] In some examples, along the direction from the first groove segment 1442 to the second groove segment 1443, the groove depth of the second groove segment 1443 is arranged to decrease from the first groove segment 1442, and the groove depth of the second groove segment 1443 gradually decreases compared with the groove depth of the first groove segment 1442, so as to form a pressure difference of electrolyte flow, the second groove segment 1443 can generate a better siphon effect, electrolyte can be quickly sucked into the second groove segment 1443 and quickly backflow to the first groove segment 1442 through the second groove segment 1443, and the first wetting effect can be better improved, and the cycle performance of the cylindrical battery cell 6 can be improved.

[0382] In some examples, along the direction from the first groove segment 1442 to the second groove segment 1443, the groove width of the second groove segment 1443 is arranged to decrease from the first groove segment 1442, and the groove width of the second groove segment 1443 gradually decreases compared with the groove width of the first groove segment 1442, so as to form a pressure difference of electrolyte flow, the second groove segment 1443 can generate a better siphon effect, electrolyte can be quickly sucked into the second groove segment 1443 and quickly backflow to the first groove segment 1442 through the second groove segment 1443, and the first wetting effect can be better improved, and the cycle performance of the cylindrical battery cell 6 can be improved.

[0383] In some examples, along the direction from the first groove segment 1442 to the second groove segment 1443, the groove depth of the second groove segment 1443 is arranged to decrease from the first groove segment 1442, and the groove width of the second groove segment 1443 is arranged to decrease from the first groove segment 1442, so as to form a larger pressure difference of electrolyte flow, the second groove segment 1443 can generate a better siphon effect, electrolyte can be quickly sucked into the second groove segment 1443 and quickly backflow to the first groove segment 1442 through the second groove segment 1443, and the first wetting effect can be better improved, and the cycle performance of the cylindrical battery cell 6 can be improved.

[0384] Referring to Figure 19As shown, in some embodiments, the first groove 1441 includes a plurality of sub-segments 1445, which are spaced along the axial direction Z of the cylindrical battery cell 6.

[0385] The first groove 1441 is of a segmented structure, and includes a plurality of sub-segments 1445, which are not connected and have a certain spacing between adjacent two sub-segments 1445. The plurality of sub-segments 1445 can be equidistantly arranged or non-equidistantly arranged.

[0386] By adopting the technical solution of this embodiment, the first groove 1441 includes a plurality of sub-segments 1445, which can reduce the removal of active material by slotting of the first active material layer 142 and reduce the loss amount of active material of the first tab 14, thereby being conducive to improving the use performance of the battery cell. In addition, the plurality of sub-segments 1445 are spaced, which is conducive to improving the structural strength and rigidity of the first tab 14 and the use reliability of the cylindrical battery cell 6, compared with the use of a whole segment first groove 1441.

[0387] In some embodiments, along the axial direction Z of the cylindrical battery cell 6, the spacing between adjacent two sub-segments 1445 is d, and 0.1mm≤d≤1mm.

[0388] In some examples, the value of d can be 0.1mm, 1mm or any value between 0.1mm and 1mm. For example, the value of d can be, but is not limited to, 0.1mm, 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm or 1mm.

[0389] The design of d≥0.1mm makes the adjacent two sub-segments 1445 be spaced, which reduces the loss amount of active material of the first tab 14 and improves the use performance of the cylindrical battery cell 6. The design of d≤1mm makes the electrolyte between adjacent two sub-segments 1445 flow to each other, which makes the distribution of electrolyte more uniform and is conducive to improving the cycle performance of the cylindrical battery cell 6.

[0390] In some embodiments, 0.3mm≤d≤0.6mm, which can better balance the cycle performance and use performance of the cylindrical battery cell 6.

[0391] Referring to Figure 20 As shown, in some embodiments, the distance between adjacent two sub-segments 1445 of one of the two first grooves 1441 can be the same as or different from the distance between adjacent two sub-segments 1445 of the other first groove 1441.

[0392] Referring to Figure 21As shown, in some embodiments, along the winding direction V of the electrode assembly 10, in the two adjacent first grooves 1441, the sub-segments 1445 of one of the first grooves 1441 are staggered with at least part of the sub-segments 1445 of the other first groove 1441.

[0393] In some examples, along the winding direction V of the electrode assembly 10, in the two adjacent first grooves 1441, the projection of the sub-segments 1445 of one of the first grooves 1441 does not coincide or partially coincides with the projection of the sub-segments 1445 of the other first groove 1441.

[0394] In some examples, along the winding direction V of the electrode assembly 10, in the two adjacent first grooves 1441, the electrolyte in the two adjacent sub-segments 1445 in the first one of the first grooves 1441 is not easy to infiltrate to the middle position of the two sub-segments 1445, while the sub-segments 1445 of the second one of the first grooves 1441 are oppositely arranged with the middle position between the two adjacent sub-segments 1445 of the first one of the first grooves 1441, so that the sub-segments 1445 of the second one of the first grooves 1441 can be used to infiltrate the middle position between the two adjacent sub-segments 1445 of the first one of the first grooves 1441, reducing the infiltration dead angle of the first electrode plate 14, improving the uniformity of the electrolyte distribution, and being conducive to improving the infiltration effect of the first electrode plate 14 and the cycle performance of the cylindrical battery cell 6.

[0395] By adopting the technical scheme of this embodiment, the multiple sub-segments 1445 of the two adjacent first grooves 1441 are staggered, which is conducive to improving the uniformity of the electrolyte distribution, improving the infiltration effect of the first electrode plate 14, and improving the cycle performance of the cylindrical battery cell 6.

[0396] Referring to Figure 22 As shown, in some embodiments, the number of grooves 144 is multiple, and the multiple grooves 144 form multiple groups of grooves 144, each group of grooves 144 includes multiple intersecting grooves 144, and the multiple groups of grooves 144 are arranged at intervals along the winding direction V of the electrode assembly 10.

[0397] The multiple grooves 144 are divided into multiple groups, and each group of grooves 144 includes multiple intersecting grooves 144. In some examples, each group of grooves 144 includes two intersecting grooves 144, and the two grooves 144 form an X-shaped structure. Of course, in other examples, each group of grooves 144 can also include three, four, or more than five grooves 144.

[0398] By adopting the technical scheme of the embodiment, the plurality of grooves 144 are divided into a plurality of groups, each group of grooves 144 includes a plurality of intersecting grooves 144, and the electrolyte can flow in the plurality of grooves 144, which is beneficial to improve the uniformity of electrolyte distribution, improve the wettability of the first pole piece 14, and improve the cycle performance of the cylindrical battery monomer 6. In addition, the plurality of groups of grooves 144 are arranged at intervals along the winding direction V of the electrode assembly 10, which can reduce the loss of active material of the first pole piece 14, is beneficial to improve the capacity of the cylindrical battery monomer 6, and at the same time, can also improve the structural strength and rigidity of the first pole piece 14, and is beneficial to improve the use reliability of the cylindrical battery monomer 6.

[0399] Referring to Figure 5 , Figure 6 and Figure 23 , in some embodiments, the number of the first pole piece winding turns 143 is n, n≥30, n is a natural number, the innermost one of the first pole piece winding turns 143 is the first first pole piece winding turn 143, and at least one of the first 10 first pole piece winding turns 143 is provided with a groove 144.

[0400] For example, n is 30, 40, 50, 60, 70, 80, 90, 100, 150, or 200.

[0401] The plurality of first pole piece winding turns 143 are sequentially arranged from the inside to the outside of the electrode assembly 10, the innermost one of the first pole piece winding turns 143 of the electrode assembly 10 is the first first pole piece winding turn 143, and the first first pole piece winding turn 143 is closest to the center axis X1 of the cylindrical battery monomer 6 compared with other first pole piece winding turns 143.

[0402] At least one of the first 10 first pole piece winding turns 143 is provided with a groove 144, from the first to the tenth first pole piece winding turn 143, one first pole piece winding turn 143 is provided with a groove 144; or, from the first to the tenth first pole piece winding turn 143, a plurality of first pole piece winding turns 143 are provided with grooves 144. The 11th to the nth first pole piece winding turn 143 can be partially provided with grooves 144, can be entirely provided with grooves 144, or can not be provided with grooves 144.

[0403] For example, the first and second first pole piece winding turns 143 are not provided with grooves 144, and the third to the tenth first pole piece winding turns 143 are all provided with grooves 144.

[0404] For example, the first to the fifth first pole piece winding turns 143 are not provided with grooves 144, and the sixth to the tenth first pole piece winding turns 143 are all provided with grooves 144.

[0405] For example, the first to tenth first pole piece winding turns 143 are each provided with a groove 144. Of course, in other examples, the grooves 144 can also have other distribution manners among the first to tenth first pole piece winding turns 143.

[0406] By adopting the technical scheme of this embodiment, the number of the first pole piece winding turns 143 is n, n≥30, the number of winding turns of the first pole piece 14 is large, and the radial dimension of the interval winding turn G on the inner side of the electrode assembly 10 is small, which increases the difficulty of backflow of the electrolyte on the inner side of the electrode assembly 10, and at least one of the first ten first pole piece winding turns 143 is provided with a groove 144, which can improve the backflow of the electrolyte on the inner side of the electrode assembly 10 through the groove 144 and improve the wetting effect on the inner side of the electrode assembly 10, thereby effectively improving the cycle performance of the cylindrical battery monomer 6.

[0407] Referring to FIGS. 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10, Figure 5 , Figure 6 and Figure 24 In some embodiments, the number of the first pole piece winding turns 143 is n, n≥30, n is a natural number, the innermost one of the first pole piece winding turns 143 is the first first pole piece winding turn 143, and at least the first first pole piece winding turn 143 is not provided with a groove 144.

[0408] The first first pole piece winding turn 143 is not provided with a groove 144, and at least one of the second to n-th first pole piece winding turns 143 is provided with a groove 144.

[0409] After the first pole piece 14 is wound, the winding radius of the first pole piece winding turn 143 closer to the inner side is smaller, and the winding stress of the first pole piece winding turn 143 closer to the inner side is larger, wherein the winding radius of the first first pole piece winding turn 143 is smallest, the winding stress of the first first pole piece winding turn 143 is largest, and the first first pole piece winding turn 143 is not provided with a groove 144, which is beneficial to improve the structural strength of the first first pole piece winding turn 143, reduce the risk of powder falling, damage, or even fracture of the first first pole piece winding turn 143 caused by grooving, and improve the capacity and use reliability of the cylindrical battery monomer 6. In addition, the first first pole piece winding turn 143 not being provided with a groove 144 can also reduce the number of grooves, which is beneficial to improve the production efficiency of the first pole piece 14.

[0410] In some embodiments, at least the first three first pole piece winding turns 143 are not provided with a groove 144.

[0411] The first to third first pole piece winding turns 143 are each not provided with a groove 144. At least one of the fourth to n-th first pole piece winding turns 143 is provided with a groove 144.

[0412] By adopting the technical scheme of the embodiment, the winding radius of the first to third first pole piece winding turns 143 is small, the winding stress of the first to third first pole piece winding turns 143 is large, and the first to third first pole piece winding turns 143 are not provided with the grooves 144, which is beneficial to improve the structural strength of the first to third first pole piece winding turns 143, reduce the risk of powder falling, damage, and even fracture of the first to third first pole piece winding turns 143 caused by grooving, and improve the capacity and use reliability of the cylindrical battery cell 6. In addition, the first to third first pole piece winding turns 143 are not provided with the grooves 144, which can also reduce the number of grooves and improve the production efficiency of the first pole piece 14.

[0413] As shown in Figure 6 In some embodiments, the electrode assembly 10 is provided with a center hole 101, and the first first pole piece winding turn 143 is closest to the center hole 101 compared with other first pole piece winding turns 143.

[0414] For example, the center axis X1 of the cylindrical battery cell 6 passes through the center hole 101.

[0415] The center hole 101 can be used to contain and flow electrolyte, so as to infiltrate the first pole piece winding turns 143 located on the inner side, improve the infiltration effect of the inner side of the electrode assembly 10, and improve the cycle performance of the cylindrical battery cell 6. In addition, the first pole piece winding turns 143 located on the inner side can be infiltrated by the electrolyte in the center hole 101, which can reduce the need for the first pole piece winding turns 143 located on the inner side to be provided with grooves 144, improve the structural strength of the first pole piece winding turns 143 on the inner side, and reduce the problem of powder falling of the first pole piece winding turns 143 on the inner side, so as to effectively balance the capacity, cycle performance, and use reliability of the cylindrical battery cell 6.

[0416] The center hole 101 can also provide space for the expansion of the inner side of the electrode assembly 10, so as to reduce the extrusion effect on the shell 20, reduce the risk of deformation and cracking of the shell 20, and improve the reliability of the cylindrical battery cell 6.

[0417] When the cylindrical battery cell 6 appears thermal runaway, the center hole 101 can be used as a gas discharge channel to improve the discharge rate of the gas and reduce the risk of explosion.

[0418] As shown in Figure 5 , Figure 6 and Figure 24 In some embodiments, the number of first pole piece winding turns 143 is n, n≥30, and n is a natural number; the innermost one of the first pole piece winding turns 143 is the first first pole piece winding turn 143; and at least the last two first pole piece winding turns 143 are not provided with the grooves 144.

[0419] The n-1th to n th first pole piece winding turns 143 are not provided with the grooves 144. At least one of the 1st to n-2th first pole piece winding turns 143 is provided with the groove 144.

[0420] The electrode assembly 10 expands, and the expansion force of the electrode assembly 10 is accumulated on the outer side. The expansion accumulation force of the last 2 first pole piece winding turns 143 is the largest, and the last 2 first pole piece winding turns 143 are not provided with the groove 144, which is beneficial to improve the structural strength of the last 2 first pole piece winding turns 143 and reduce the risk of fracture of the last 2 first pole piece winding turns 143, thereby effectively improving the use reliability of the cylindrical battery monomer 6. In addition, the last 2 first pole piece winding turns 143 are not provided with the groove 144, which can reduce the number of grooves and improve the production and processing efficiency of the first pole piece 14.

[0421] In some embodiments, at least the last 10 first pole piece winding turns 143 are not provided with the groove 144.

[0422] The n-9th to n th first pole piece winding turns 143 are not provided with the grooves 144. At least one of the 1st to n-8th first pole piece winding turns 143 is provided with the groove 144.

[0423] The expansion accumulation force of the last 10 first pole piece winding turns 143 is larger, and the last 10 first pole piece winding turns 143 are not provided with the groove 144, which is beneficial to improve the structural strength of the last 10 first pole piece winding turns 143 and reduce the risk of fracture of the last 10 first pole piece winding turns 143, thereby better improving the use reliability of the cylindrical battery monomer 6. In addition, the last 10 first pole piece winding turns 143 are not provided with the groove 144, which can reduce the number of grooves and improve the production and processing efficiency of the first pole piece 14. The radial dimension of the gap winding turn G on the outer side of the electrode assembly 10 is large, the backflow effect of the electrolyte is good, and the outer side of the electrode assembly 10 is not grooved, which can better balance the capacity, cycle performance and use reliability of the cylindrical battery monomer 6.

[0424] In some embodiments, the number of the first pole piece winding turns 143 is n, n≥30, n is a natural number; the innermost one of the first pole piece winding turns 143 is the 1st first pole piece winding turn 143; the first f first pole piece winding turns 143 are not provided with the groove 144, and the last q first pole piece winding turns 143 are not provided with the groove 144; all the first pole piece winding turns 143 between the fth first pole piece winding turn 143 and the last q first pole piece winding turn 143 are provided with the groove 144, f+q

[0425] f and q are natural numbers greater than 1, for example, f is 1, 3, 5, 7, 10, 20, etc., and q is 1, 5, 10, 15, 20, 30, 40, etc.

[0426] For example, when f is 1 and q is 1, the first first-plate-winding turn 143 is not provided with the groove 144, the second to the (n-1)th first-plate-winding turn 143 is each provided with the groove 144, and the nth first-plate-winding turn 143 is not provided with the groove 144.

[0427] For example, when f is greater than 1 and q is greater than 1, the first to the fth first-plate-winding turn 143 is not provided with the groove 144, the (f+1)th to the (n-q)th first-plate-winding turn 143 is provided with the groove 144, and the (n-q+1)th to the nth first-plate-winding turn 143 is not provided with the groove 144.

[0428] By adopting the technical solutions of this embodiment, the first-plate-winding turns 143 located at the inner side and the outer side are not provided with the groove 144, which is beneficial to improving the structural strength of the first-plate-winding turns 143 at the inner side and the outer side, improving the use reliability of the cylindrical battery monomer 6, and in addition, the number of grooves can be reduced and the production and processing efficiency of the first plate 14 can be improved. Moreover, the electrode assembly 10 is grooved at the middle region between the inner side and the outer side, which is beneficial to improving the impregnation effect of the electrode assembly 10 at the middle region between the inner side and the outer side and improving the cycle performance of the cylindrical battery monomer 6.

[0429] In some embodiments, 30≤n≤80.

[0430] For example, n is 30, 40, 50, 60, 65, 70, 75, 80, 90, etc.

[0431] The design of 30≤n≤80 makes the number of the first-plate-winding turns 143 large, the capacity of the cylindrical battery monomer 6 large, and the impregnation difficulty of the electrode assembly 10 large, and in the embodiments of the present application, the groove 144 can be selectively arranged at the inner side or the outer side of the electrode assembly 10, so as to improve the impregnation effect of the electrode assembly 10 and also improve the structural strength of the inner side or the outer side of the electrode assembly 10, which can take into account the use reliability, capacity and cycle performance of the electrode assembly 10.

[0432] In some embodiments, 60≤n≤75, which better takes into account the use reliability, capacity and cycle performance of the electrode assembly 10.

[0433] In some embodiments, the number of the first-plate-winding turns 143 provided with the groove 144 is v, and 0.23≤v / n≤1, v and n are positive integers, and optionally, 0.3≤v / n≤0.7.

[0434] In some examples, the value of v / n can be 0.23, 1 or any value between 0.23 and 1; for example, the value of v / n can be but is not limited to 0.23, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.

[0435] The design with 0.23≤v / n≤1 can meet the wetting requirements of the electrode assembly 10 and improve the cycle performance of the cylindrical battery cell 6.

[0436] In some embodiments, 0.3 ≤ v / n ≤ 0.7.

[0437] With a v / n ≥ 0.3 design, the number of first electrode winding coils 143 with grooves 144 can better meet the wetting requirements of the electrode assembly 10 and improve the cycle performance of the cylindrical battery cell 6; with a v / n ≤ 0.7 setting, some of the first electrode winding coils 143 are not provided with grooves 144, which helps to reduce the number of grooves and improve the production efficiency of the first electrode 14.

[0438] See Figure 5 , Figure 6 and Figure 24 As shown, in some embodiments, the first electrode 14 has a first winding end A2, the second electrode 15 has a second winding end B2, the innermost first electrode winding coil 143 is the first first electrode winding coil 143, and the second winding end B2 is located between the last two first electrode winding coils 143; the last two first electrode winding coils 143 are not provided with grooves 144 at the positions corresponding to the end faces of the first winding end A2; and / or, the last two first electrode winding coils 143 are not provided with grooves 144 at the positions corresponding to the end faces of the second winding end B2.

[0439] The first electrode 14 has a first winding end A2 and a first winding start end A1. Along the winding direction V of the electrode assembly 10, of the two relatively distributed ends of the first electrode 14, the end closer to the central axis X1 of the cylindrical battery cell 6 is the first winding start end A1, and the end farther from the central axis X1 of the cylindrical battery cell 6 is the first winding end A2. Along the winding direction V of the electrode assembly 10, of the two relatively distributed end faces of the first electrode 14, the end face closer to the central axis X1 of the cylindrical battery cell 6 is the end face of the first winding start end A1, and the end face farther from the central axis X1 of the cylindrical battery cell 6 is the end face of the first winding end A2.

[0440] For example, along the winding direction V of the electrode assembly 10, the first winding end A2 can refer to the end of the penultimate first electrode winding 143 that is away from the penultimate first electrode winding 143, and the first winding start end A1 can refer to the end of the first first electrode winding 143 that is away from the second first electrode winding 143.

[0441] The second tab 15 has a second winding ending end B2 and a second winding starting end Bl, of which the two ends of the second tab 15 are oppositely distributed along the winding direction V of the electrode assembly 10, wherein the end close to the central axis X1 of the cylindrical battery cell 6 is the second winding starting end Bl, and the end away from the central axis X1 of the cylindrical battery cell 6 is the second winding ending end B2. The two end faces of the second tab 15 are oppositely distributed along the winding direction V of the electrode assembly 10, wherein the end face close to the central axis X1 of the cylindrical battery cell 6 is the end face of the second winding starting end Bl, and the end face away from the central axis X1 of the cylindrical battery cell 6 is the end face of the second winding ending end B2.

[0442] For example, along the winding direction V of the electrode assembly 10, the second winding ending end B2 can refer to the end of the last second tab winding circle 153 away from the second last second tab winding circle 153, and the second winding starting end Bl can refer to the end of the first second tab winding circle 153 away from the second second tab winding circle 153.

[0443] In some examples, after the winding of the second tab 15 is completed, the first tab 14 continues to be wound forward for a distance and continues to be wound for less than one circle along the winding direction V of the electrode assembly 10, so that the second last two first tab winding circles 143 can completely cover the second winding ending end B2, and the second winding ending end B2 is located between the second last two first tab winding circles 143, and the first winding ending end A2 and the second last first tab winding circle 143 are not provided with the second tab winding circle 153.

[0444] The position corresponding to the end face of the second last two first tab winding circles 143 and the first winding ending end A2 is not provided with the groove 144, and it can be understood that the position opposite to the end face of the second last first tab winding circle 143 and the first winding ending end A2 is not provided with the groove 144.

[0445] The position corresponding to the end face of the second last two first tab winding circles 143 and the second winding ending end B2 is not provided with the groove 144, and it can be understood that the position opposite to the end face of the second last first tab winding circle 143 and the second winding ending end B2 is not provided with the groove 144, and the position opposite to the end face of the second winding ending end B2 and the second last first tab winding circle 143 is not provided with the groove 144.

[0446] In the expansion process of the electrode assembly 10, the second last first tab winding 143 is pressed by the first last first tab winding 143, and in this process, the edge of the end face of the first winding end A2 presses the second last first tab winding 143, the end face of the second winding end B2 is clamped between the second last two first tab windings 143, and the edge of the end face of the second winding end B2 presses the first last first tab winding 143 and the second last first tab winding 143; if the second last two first tab windings 143 are provided with a groove 144 at a position corresponding to the end face of the first winding end A2, the end face of the first winding end A2 is opposite to the groove 144 and presses the groove 144, the structural strength of the groove 144 is poor, and the end face of the first winding end A2 has the risk of cutting the second last two first tab windings 143, and for the same reason, if the second last two first tab windings 143 are provided with a groove 144 at a position corresponding to the end face of the second winding end B2, the end face of the second winding end B2 is opposite to the groove 144 and presses the groove 144, the structural strength of the groove 144 is poor, and the end face of the second winding end B2 has the risk of cutting the second last two first tab windings 143.

[0447] In some examples, the first tab 14 has a first winding end A2, the second tab 15 has a second winding end B2, the innermost first tab winding 143 is the first first tab winding 143, and the second winding end B2 is located between the second last two first tab windings 143; the position corresponding to the end face of the first winding end A2 of the second last two first tab windings 143 is not provided with a groove 144.

[0448] For example, the position corresponding to the end face of the first winding end A2 of the second last second tab winding 143 is not provided with a groove 144.

[0449] In the expansion process of the electrode assembly 10, the position corresponding to the end face of the first winding end A2 of the second last two first tab windings 143 is not provided with a groove 144, the structural strength of the position corresponding to the end face of the first winding end A2 of the second last two first tab windings 143 is good, the risk of cutting the second last two first tab windings 143 by the end face of the first winding end A2 is reduced, and the use reliability of the cylindrical battery monomer 6 is improved.

[0450] In some examples, the first tab 14 has a first winding end A2, the second tab 15 has a second winding end B2, the innermost first tab winding 143 is the first first tab winding 143, and the second winding end B2 is located between the second last two first tab windings 143; the position corresponding to the end face of the second winding end B2 of the second last two first tab windings 143 is not provided with a groove 144.

[0451] For example, the position corresponding to the end surface of the second winding end B2 of the last first pole piece winding turn 143 is not provided with the groove 144; the position corresponding to the end surface of the second winding end B2 of the second last first pole piece winding turn 143 is not provided with the groove 144.

[0452] In the process of expansion of the electrode assembly 10, the position corresponding to the end surface of the second winding end B2 of the second last first pole piece winding turn 143 is not provided with the groove 144, the structural strength of the position corresponding to the end surface of the second winding end B2 of the second last first pole piece winding turn 143 is good, the risk of the second last first pole piece winding turn 143 being cut off by the end surface of the second winding end B2 is reduced, and the use reliability of the cylindrical battery monomer 6 is improved.

[0453] In some examples, the first pole piece 14 has a first winding end A2, the second pole piece 15 has a second winding end B2, the innermost first pole piece winding turn 143 is the first first pole piece winding turn 143, and the second winding end B2 is located between the second last first pole piece winding turn 143; the position corresponding to the end surface of the first winding end A2 of the second last first pole piece winding turn 143 is not provided with the groove 144; the position corresponding to the end surface of the second winding end B2 of the second last first pole piece winding turn 143 is not provided with the groove 144.

[0454] For example, the position corresponding to the end surface of the second winding end B2 of the last first pole piece winding turn 143 is not provided with the groove 144; the position corresponding to the end surface of the second winding end B2 of the second last first pole piece winding turn 143 is not provided with the groove 144, and the position corresponding to the end surface of the first winding end A2 of the second last first pole piece winding turn 143 is not provided with the groove 144.

[0455] In the process of expansion of the electrode assembly 10, the position corresponding to the end surface of the first winding end A2 and the end surface of the second winding end B2 of the second last first pole piece winding turn 143 is not provided with the groove 144, the structural strength of the position corresponding to the end surface of the first winding end A2 and the end surface of the second winding end B2 of the second last first pole piece winding turn 143 is good, the risk of the second last first pole piece winding turn 143 being cut off by the end surface of the first winding end A2 and the end surface of the second winding end B2 is reduced, and the use reliability of the cylindrical battery monomer 6 is improved.

[0456] In some embodiments, the second last first pole piece winding turn 143 is provided with the groove 144, and the groove 144 is arranged to be staggered with at least one of the end surface of the first winding end A2 and the end surface of the second winding end B2.

[0457] The count-2 first pole piece winding circle 143 is provided with a groove 144. It can be understood that at least one of the count-1 first pole piece winding circle 143 or the count-2 first pole piece winding circle 143 is provided with a groove 144. The count-2 first pole piece winding circle 143 is provided with a groove 144, which can improve the wetting effect of the count-2 first pole piece winding circle 143 and improve the cycle performance of the cylindrical battery cell 6.

[0458] In some examples, the count-2 first pole piece winding circle 143 is provided with a groove 144, and the groove 144 is arranged away from the end face of the first winding end A2.

[0459] For example, the count-2 first pole piece winding circle 143 is provided with a groove 144, and the groove 144 is arranged away from the end face of the first winding end A2. The count-1 first pole piece winding circle 143 can be provided with a groove 144 or not.

[0460] The groove 144 of the count-2 first pole piece winding circle 143 is not arranged opposite to the end face of the first winding end A2, which reduces the risk of the count-2 first pole piece winding circle 143 being cut off by the end face of the first winding end A2, and improves the use reliability of the cylindrical battery cell 6.

[0461] In some examples, the count-2 first pole piece winding circle 143 is provided with a groove 144, and the groove 144 is arranged away from the end face of the second winding end B2.

[0462] For example, the count-1 first pole piece winding circle 143 is provided with a groove 144, and the count-2 first pole piece winding circle 143 is not provided with a groove 144, and the groove 144 of the count-1 first pole piece winding circle 143 is arranged away from the end face of the second winding end B2.

[0463] For example, the count-2 first pole piece winding circle 143 is provided with a groove 144, and the count-1 first pole piece winding circle 143 is not provided with a groove 144, and the groove 144 of the count-2 first pole piece winding circle 143 is arranged away from the end face of the second winding end B2.

[0464] For example, the count-1 first pole piece winding circle 143 and the count-2 first pole piece winding circle 143 are provided with grooves 144, and the groove 144 of the count-1 first pole piece winding circle 143 and the groove 144 of the count-2 first pole piece winding circle 143 are arranged away from the end face of the second winding end B2.

[0465] The groove 144 of the second last first pole piece winding ring 143 is not arranged opposite to the end surface of the second winding end B2, which reduces the risk of the second last first pole piece winding ring 143 being cut by the end surface of the second winding end B2, and improves the use reliability of the cylindrical battery cell 6.

[0466] In some examples, the second last first pole piece winding ring 143 is provided with a groove 144, and the groove 144 is arranged away from the end surface of the first winding end A2 and the end surface of the second winding end B2.

[0467] For example, the first last first pole piece winding ring 143 is provided with a groove 144, the second last first pole piece winding ring 143 is not provided with a groove 144, and the groove 144 of the first last first pole piece winding ring 143 is arranged away from the end surface of the second winding end B2.

[0468] For example, the second last first pole piece winding ring 143 is provided with a groove 144, the first last first pole piece winding ring 143 is not provided with a groove 144, and the groove 144 of the second last first pole piece winding ring 143 is arranged away from the end surface of the first winding end A2 and the end surface of the second winding end B2.

[0469] For example, the first last first pole piece winding ring 143 and the second last first pole piece winding ring 143 are provided with grooves 144, the groove 144 of the first last first pole piece winding ring 143 and the groove 144 of the second last first pole piece winding ring 143 are both arranged away from the end surface of the second winding end B2, and the groove 144 of the second last first pole piece winding ring 143 is arranged away from the end surface of the first winding end A2.

[0470] The groove 144 of the second last first pole piece winding ring 143 is not arranged opposite to the end surface of the second winding end B2, and the groove 144 of the second last first pole piece winding ring 143 is not arranged opposite to the end surface of the first winding end A2, which reduces the risk of the second last first pole piece winding ring 143 being cut by the end surface of the first winding end A2 and the end surface of the second winding end B2, and improves the use reliability of the cylindrical battery cell 6.

[0471] In some examples, the second last first pole piece winding ring 143 is not provided with a groove 144.

[0472] The first last first pole piece winding ring 143 and the second last first pole piece winding ring 143 are not provided with grooves 144.

[0473] By adopting the technical scheme of the embodiment, the count-2 first pole piece winding turns 143 are not provided with the grooves 144, on the one hand, the structural strength of the count-2 first pole piece winding turns 143 is improved, on the other hand, the risk that the count-2 first pole piece winding turns 143 are cut off by the end faces of the first winding end A2 and the second winding end B2 is reduced, and the use reliability of the cylindrical battery monomer 6 is improved.

[0474] In some embodiments, the first pole piece 14 has a first winding starting end A1, the second pole piece 15 has a second winding starting end B1, the innermost first pole piece winding turn 143 is the first first pole piece winding turn 143, the second winding starting end B1 is located between the first two first pole piece winding turns 143, the positions corresponding to the end face of the first winding starting end A1 of the first two first pole piece winding turns 143 are not provided with the grooves 144, and / or the positions corresponding to the end face of the second winding starting end B1 of the first two first pole piece winding turns 143 are not provided with the grooves 144.

[0475] In some examples, along the winding direction V of the electrode assembly 10, the second pole piece 15 starts to wind after the first pole piece 14 winds for a distance, and before the second pole piece 15 winds, the first pole piece 14 winds less than one turn, so that the first two first pole piece winding turns 143 can completely cover the second winding starting end B1, the second winding starting end B1 is located between the first two first pole piece winding turns 143, and the first winding starting end A1 and the second pole piece winding turn 153 between the second winding starting end B1 and the second pole piece winding turn 153 are not provided.

[0476] The positions corresponding to the end face of the first winding starting end A1 of the first two first pole piece winding turns 143 are not provided with the grooves 144, and it can be understood that the positions opposite to the end face of the first winding starting end A1 of the second first pole piece winding turn 143 are not provided with the grooves 144.

[0477] The positions corresponding to the end face of the second winding starting end B1 of the first two first pole piece winding turns 143 are not provided with the grooves 144, and it can be understood that the positions opposite to the end face of the second winding starting end B1 of the second first pole piece winding turn 143 are not provided with the grooves 144, and the positions opposite to the end face of the first first pole piece winding turn 143 of the second winding starting end B1 are not provided with the grooves 144.

[0478] In the expansion process of the electrode assembly 10 or under the self-restoring force of the first electrode sheet 14, the first first electrode sheet winding turn 143 is pressed by the second first electrode sheet winding turn 143, the edge of the end face of the first winding starting end A1 is pressed by the second first electrode sheet winding turn 143, the end face of the second winding starting end B1 is clamped between the first two first electrode sheet winding turns 143, and the edge of the end face of the second winding starting end B1 is pressed by the first first electrode sheet winding turn 143 and the second first electrode sheet winding turn 143; if the first two first electrode sheet winding turns 143 are provided with a groove 144 at a position corresponding to the end face of the first winding starting end A1, the end face of the first winding starting end A1 is opposite to the groove 144 and presses the groove 144, the structural strength of the groove 144 is poor, and the end face of the first winding starting end A1 has a risk of cutting the first two first electrode sheet winding turns 143; similarly, if the first two first electrode sheet winding turns 143 are provided with a groove 144 at a position corresponding to the end face of the second winding starting end B1, the end face of the second winding starting end B1 is opposite to the groove 144 and presses the groove 144, the structural strength of the groove 144 is poor, and the end face of the second winding starting end B1 has a risk of cutting the first two first electrode sheet winding turns 143.

[0479] In some examples, the first electrode sheet 14 has a first winding starting end A1, the second electrode sheet 15 has a second winding starting end B1, the innermost first electrode sheet winding turn 143 is the first first electrode sheet winding turn 143, and the second winding starting end B1 is located between the first two first electrode sheet winding turns 143; the position corresponding to the end face of the first winding starting end A1 of the first two first electrode sheet winding turns 143 is not provided with a groove 144.

[0480] For example, the position corresponding to the end face of the first winding starting end A1 of the second first electrode sheet winding turn 143 is not provided with a groove 144.

[0481] In the expansion process of the electrode assembly 10 or under the self-restoring force of the first electrode sheet 14, the position corresponding to the end face of the first winding starting end A1 of the first two first electrode sheet winding turns 143 is not provided with a groove 144, the structural strength of the position corresponding to the end face of the first winding starting end A1 of the first two first electrode sheet winding turns 143 is good, the risk of cutting the first two first electrode sheet winding turns 143 by the end face of the first winding starting end A1 is reduced, and the use reliability of the cylindrical battery monomer 6 is improved.

[0482] In some examples, the first electrode sheet 14 has a first winding starting end A1, the second electrode sheet 15 has a second winding starting end B1, the innermost first electrode sheet winding turn 143 is the first first electrode sheet winding turn 143, and the second winding starting end B1 is located between the first two first electrode sheet winding turns 143; the position corresponding to the end face of the second winding starting end B1 of the first two first electrode sheet winding turns 143 is not provided with a groove 144.

[0483] For example, the first first-pole-piece winding turn 143 corresponding to the end face of the second winding starting end B1 is not provided with the groove 144; the second first-pole-piece winding turn 143 corresponding to the end face of the second winding starting end B1 is not provided with the groove 144.

[0484] In the expansion process of the electrode assembly 10 or under the self-recovery force of the first-pole-piece 14, the first two first-pole-piece winding turns 143 corresponding to the end faces of the first winding starting end A1 and the second winding starting end B1 are not provided with the groove 144, the structural strength of the positions corresponding to the end faces of the first winding starting end A1 and the second winding starting end B1 is good, the risk of the first two first-pole-piece winding turns 143 being cut by the end faces of the first winding starting end A1 and the second winding starting end B1 is reduced, and the use reliability of the cylindrical battery monomer 6 is improved.

[0485] In some examples, the first-pole-piece 14 has a first winding starting end A1, the second-pole-piece 15 has a second winding starting end B1, the innermost first-pole-piece winding turn 143 is the first first-pole-piece winding turn 143, and the second winding starting end B1 is located between the first two first-pole-piece winding turns 143; the first two first-pole-piece winding turns 143 corresponding to the end face of the first winding starting end A1 are not provided with the groove 144; the first two first-pole-piece winding turns 143 corresponding to the end face of the second winding starting end B1 are not provided with the groove 144.

[0486] For example, the first first-pole-piece winding turn 143 corresponding to the end face of the second winding starting end B1 is not provided with the groove 144; the second first-pole-piece winding turn 143 corresponding to the end face of the second winding starting end B1 is not provided with the groove 144, and the second first-pole-piece winding turn 143 corresponding to the end face of the first winding starting end A1 is not provided with the groove 144.

[0487] In the expansion process of the electrode assembly 10 or under the self-recovery force of the first-pole-piece 14, the first two first-pole-piece winding turns 143 corresponding to the end faces of the first winding starting end A1 and the second winding starting end B1 are not provided with the groove 144, the structural strength of the positions corresponding to the end faces of the first winding starting end A1 and the second winding starting end B1 is good, the risk of the first two first-pole-piece winding turns 143 being cut by the end faces of the first winding starting end A1 and the second winding starting end B1 is reduced, and the use reliability of the cylindrical battery monomer 6 is improved.

[0488] In some examples, the first two first-pole-piece winding turns 143 are provided with the groove 144, and the groove 144 is arranged to be staggered with at least one of the end face of the first winding starting end A1 and the end face of the second winding starting end B1.

[0489] The first two first pole piece winding turns 143 are provided with grooves 144. It can be understood that at least one of the first first pole piece winding turn 143 or the second first pole piece winding turn 143 is provided with the groove 144. The first two first pole piece winding turns 143 are provided with the grooves 144, which can improve the wetting effect of the first two first pole piece winding turns 143 and improve the cycle performance of the cylindrical battery cell 6.

[0490] In some examples, the first two first pole piece winding turns 143 are provided with grooves 144, and the grooves 144 are arranged away from the end face of the first winding starting end A1.

[0491] For example, the second first pole piece winding turn 143 is provided with a groove 144, and the groove 144 is arranged away from the end face of the first winding starting end A1. The first first pole piece winding turn 143 can be provided with a groove 144 or not.

[0492] The grooves 144 of the first two first pole piece winding turns 143 are not arranged opposite to the end face of the first winding starting end A1, which reduces the risk of the first two first pole piece winding turns 143 being cut off by the end face of the first winding starting end A1, and improves the use reliability of the cylindrical battery cell 6.

[0493] In some examples, the first two first pole piece winding turns 143 are provided with grooves 144, and the grooves 144 are arranged away from the end face of the second winding starting end B1.

[0494] For example, the first first pole piece winding turn 143 is provided with a groove 144, and the second first pole piece winding turn 143 is not provided with a groove 144, and the groove 144 of the first first pole piece winding turn 143 is arranged away from the end face of the second winding starting end B1.

[0495] For example, the second first pole piece winding turn 143 is provided with a groove 144, and the first first pole piece winding turn 143 is not provided with a groove 144, and the groove 144 of the second first pole piece winding turn 143 is arranged away from the end face of the second winding starting end B1.

[0496] For example, the first first pole piece winding turn 143 and the second first pole piece winding turn 143 are provided with grooves 144, and the groove 144 of the first first pole piece winding turn 143 and the groove 144 of the second first pole piece winding turn 143 are arranged away from the end face of the second winding starting end B1.

[0497] The grooves 144 of the first two first pole piece winding turns 143 are not arranged opposite to the end face of the second winding starting end B1, which reduces the risk of the first two first pole piece winding turns 143 being cut off by the end face of the second winding starting end B1, and improves the use reliability of the cylindrical battery cell 6.

[0498] In some examples, the first two first-pole-piece winding turns 143 are provided with grooves 144, and the grooves 144 are arranged away from the end faces of the first winding start end A1 and the second winding start end B1.

[0499] For example, the first first-pole-piece winding turn 143 is provided with a groove 144, the second first-pole-piece winding turn 143 is not provided with a groove 144, and the groove 144 of the first first-pole-piece winding turn 143 is arranged away from the end face of the second winding start end B1.

[0500] For example, the second first-pole-piece winding turn 143 is provided with a groove 144, the first first-pole-piece winding turn 143 is not provided with a groove 144, and the groove 144 of the second first-pole-piece winding turn 143 is arranged away from the end faces of the first winding start end A1 and the second winding start end B1.

[0501] For example, the first first-pole-piece winding turn 143 and the second first-pole-piece winding turn 143 are provided with grooves 144, the groove 144 of the first first-pole-piece winding turn 143 and the groove 144 of the second first-pole-piece winding turn 143 are both arranged away from the end face of the second winding start end B1, and the groove 144 of the second first-pole-piece winding turn 143 is arranged away from the end face of the first winding start end A1.

[0502] The grooves 144 of the first two first-pole-piece winding turns 143 are not arranged opposite to the end face of the second winding start end B1, and the grooves 144 of the first two first-pole-piece winding turns 143 are not arranged opposite to the end face of the first winding start end A1, thereby reducing the risk of the first two first-pole-piece winding turns 143 being cut by the end faces of the first winding start end A1 and the second winding start end B1, and improving the use reliability of the cylindrical battery cell 6.

[0503] In some examples, the first two first-pole-piece winding turns 143 are not provided with grooves 144.

[0504] The first first-pole-piece winding turn 143 and the second first-pole-piece winding turn 143 are not provided with grooves 144.

[0505] By adopting the technical solution of this example, the first two first-pole-piece winding turns 143 are not provided with grooves 144, on the one hand, the structural strength of the first two first-pole-piece winding turns 143 is improved, and on the other hand, the risk of the first two first-pole-piece winding turns 143 being cut by the end faces of the first winding start end A1 and the second winding start end B1 is reduced, thereby improving the use reliability of the cylindrical battery cell 6.

[0506] In some examples, the first pole piece 14 is a negative pole piece 12, and the second pole piece 15 is a positive pole piece 11.

[0507] With the second winding end B2 located at the second to last winding end of the first electrode 14, along the winding direction V of the electrode assembly 10, the winding end of the negative electrode 12 extends beyond the winding end of the positive electrode 11. The portion of the negative electrode 12 that extends beyond the positive electrode 11 provides more space for ions to intercalate, reducing the risk of lithium plating and improving the reliability of the cylindrical battery cell 6.

[0508] Based on the second winding start end B1 being located at the winding ends of the first two first electrode sheets 14, along the winding direction V of the negative electrode sheet 12 of the electrode assembly 10, the negative electrode sheet 12 needs to be wound for a certain distance before the positive electrode sheet 11 begins to be wound. The part of the negative electrode sheet 12 wound first can provide more space for ions to be inserted, reduce the risk of lithium plating, and improve the reliability of the cylindrical battery cell 6.

[0509] In other embodiments, the second electrode 15 is the negative electrode 12, and the first electrode 14 is the positive electrode 11.

[0510] See Figure 25 and Figure 26 As shown, in some embodiments, the first electrode 14 includes a first current collector 141 and a first active material layer 142. At least a portion of at least one surface of the first current collector 141 along its thickness direction is connected to the first active material layer 142. At least a portion of the first active material layer 142 is located between the first current collector 141 and the separator 13. The first electrode 14 is wound to form a plurality of first electrode winding coils 143. The first active material layer 142 includes a first active winding coil 1432 located on the first electrode winding coil 143. The first current collector 141 includes a first current collecting winding coil 1431 located on the first electrode winding coil 143. The surface of the first active material layer 142 facing away from the current collector includes a first winding surface 1433 located on the first electrode winding coil 143.

[0511] The first current collector 141 has a first active material layer 142 covering one surface along its thickness direction, or both surfaces of the first current collector 141 along its thickness direction are covered with the first active material layer 142.

[0512] The first active material layer 142 may cover a portion of the surface of the first current collector 141, or it may cover the entire surface of the first current collector 141.

[0513] The first active material layer 142 can be directly applied to the first current collector 141. Alternatively, other layer structures, such as a conductive protective layer, can be provided between the first active material layer 142 and the first current collector 141. The conductive protective layer can be made by mixing a conductive agent and an adhesive. The adhesive bonds the first active material layer 142 and the first current collector 141, while the conductive agent is responsible for conducting electrons. The conductive agent can be carbon black, graphite, etc., and the adhesive can be polyvinylidene fluoride, etc.

[0514] In some embodiments, the first active material layer 142 includes a first active material portion 1422 and a second active material portion 1423 arranged along the axial direction Z of the cylindrical battery cell 6, the first active material portion 1422 is connected with the second active material portion 1423 at at least one end along the axial direction Z of the cylindrical battery cell 6, and the thickness of the second active material portion 1423 is less than the thickness of the first active material portion 1422.

[0515] The first active material portion 1422 is connected with the second active material portion 1423 at one end along the axial direction Z of the cylindrical battery cell 6, or the first active material portion 1422 is connected with the second active material portion 1423 at both ends along the axial direction Z of the cylindrical battery cell 6.

[0516] The thickness of the second active material portion 1423 is less than the thickness of the first active material portion 1422, and the boundary between the first active material portion 1422 and the second active material portion 1423 can refer to the thickness transition position of the first active material layer 142; the second active material portion 1423 can be a thinned region of the first active material layer 142.

[0517] In some examples, the second active material portion 1423 and the first active material portion 1422 can be substantially equal-thickness structures, the thickness of the second active material portion 1423 is less than the thickness of the first active material portion 1422, so that the second active material portion 1423 and the first active material portion 1422 form a stepped structure.

[0518] In some examples, the first active material portion 1422 can be substantially equal-thickness structure, along the direction of the first active material portion 1422 pointing to the second active material portion 1423, the thickness of the second active material portion 1423 is arranged to decrease from the first active material portion 1422, so that the thickness of the second active material portion 1423 is less than the thickness of the first active material portion 1422.

[0519] In some examples, the direction of the first active material portion 1422 pointing to the second active material portion 1423 can refer to the direction indicated by the upward arrow Z in FIG. Figure 26

[0520] ​By adopting the technical solutions of this embodiment, the thickness of the second active material portion 1423 is less than the thickness of the first active material portion 1422, so that the surface of the second active material portion 1423 facing away from the first current collector 141 is closer to the first current collector 141 than the surface of the first active material portion 1422 facing away from the first current collector 141. On the one hand, the edge portion of the first active material layer 142 can be subjected to less rolling pressure during rolling of the first electrode sheet 14, and the risk of cracking of the edge portion of the first active material layer 142 can be reduced. On the other hand, the side portion of the second active material portion 1423 facing away from the first current collector 141 can accommodate more electrolyte, so that the backflow of the electrolyte is facilitated, and the thickness difference between the second active material portion 1423 and the first active material portion 1422 can be used to form a siphon effect, so that the speed of backflow of the electrolyte is increased, the wetting effect of the electrode assembly 10 is improved, and the cycle performance of the cylindrical battery cell 6 is improved.

[0521] In some embodiments, along a direction in which the first active material portion 1422 points to the second active material portion 1423, the thickness of the second active material portion 1423 decreases.

[0522] For example, along a direction in which the first active material portion 1422 points to the second active material portion 1423, the thickness of the second active material portion 1423 decreases in steps, so that the second active material portion 1423 has a stepped structure. Alternatively, along a direction in which the first active material portion 1422 points to the second active material portion 1423, the thickness of the second active material portion 1423 decreases slowly, and the outer shape of the second active material portion 1423 is more smooth, which is beneficial to reducing stress concentration and improving the structural strength of the positive electrode sheet 11.

[0523] In some examples, along a direction in which the first active material portion 1422 points to the second active material portion 1423, the end surface of the second active material layer 152 exceeds the end surface of the second active material portion 1423 close to the first active material portion 1422, and the thickness of the second active material portion 1423 decreases, so that a horn structure can be formed between the second active material portion 1423 and the second active material layer 152. The large end of the horn structure faces away from the first active material portion 1422. The horn structure makes it easier for the electrolyte to be sucked between the first active material portion 1422 and the second electrode sheet 15, which is more beneficial to improving the wetting effect of the electrode assembly 10 and improving the cycle performance of the cylindrical battery cell 6.

[0524] In some examples, along a direction in which the first active material portion 1422 points to the second active material portion 1423, an end surface of the second active material layer 152 does not exceed an end surface of the second active material portion 1423 close to the first active material portion 1422, and the second active material portions 1423 of two adjacent first tab winding turns 143 also form a horn structure, a large end of the horn structure is arranged away from the first active material portion 1422, and the horn structure is arranged so that the electrolyte is more easily absorbed between the first active material portion 1422 and the second tab 15, which is more conducive to improving the impregnation effect of the electrode assembly 10 and improving the cycle performance of the cylindrical battery cell 6.

[0525] In some embodiments, the first active material portion 1422 has a first surface 1424 facing away from the first current collector 141, and the second active material portion 1423 has a second surface 1425 facing away from the first current collector 141, and the second surface 1425 is closer to the first current collector 141 than the first surface 1424.

[0526] The distance between the second surface 1425 and the first current collector 141 is less than the distance between the first surface 1424 and the first current collector 141.

[0527] By adopting the technical solutions of this embodiment, the side of the second surface 1425 facing away from the first current collector 141 has more space for accommodating electrolyte, and the distance difference between the second surface 1425 and the first surface 1424 and the first current collector 141 can be used to form a siphon effect, improve the speed of electrolyte backflow, improve the impregnation effect of the electrode assembly 10, and improve the cycle performance of the cylindrical battery cell 6.

[0528] In some embodiments, the first active material portion 1422 is provided with a groove 144, and the second active material portion 1423 is arranged away from the groove 144 along the axial direction Z of the cylindrical battery cell 6.

[0529] There is a distance between the second active material portion 1423 and the groove 144 along the axial direction Z of the cylindrical battery cell 6, so that the groove 144 of the first active material portion 1422 does not extend to the second active material portion 1423.

[0530] By adopting the technical solutions of this embodiment, the first active material portion 1422 is provided with a groove 144, which can improve the impregnation effect of the first active material portion 1422 and improve the cycle performance of the cylindrical battery cell 6, and the second active material portion 1423 is arranged away from the groove 144, which is conducive to improving the structural strength of the second active material portion 1423, reducing the risk of powder falling or even collapsing of the second active material portion 1423 due to winding, and improving the capacity and use reliability of the cylindrical battery cell 6, so that the cycle performance, capacity and use reliability of the cylindrical battery cell 6 can be considered.

[0531] In some embodiments, along the axial direction Z of the cylindrical battery cell 6, the distance between the second active material portion 1423 and the groove 144 is S1, where 0mm < S1≤ 18mm.

[0532] In some examples, S1 can be 18mm or any value between 0mm and 18mm, for example, S1 can be 0.1mm, 1mm, 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 12mm, 14mm, 16mm, 18mm.

[0533] S1>0mm, so that the groove 144 does not extend to the second active material portion 1423, which is conducive to improving the structural strength of the second active material portion 1423, and can reduce the risk of powder falling or even collapsing of the second active material portion 1423 due to winding, which is conducive to improving the capacity and use reliability of the cylindrical battery cell 6; the design of S1≤18mm makes the electrolyte located on the side of the second active material portion 1423 away from the first current collector 141 closer to the groove 144, so that the electrolyte can flow better into the groove 144, improving the impregnation effect of the first electrode plate 14 and improving the cycle performance of the cylindrical battery cell 6. Therefore, the cycle performance, capacity and use reliability of the cylindrical battery cell 6 can be considered.

[0534] In some embodiments, 2mm≤S1≤8mm, which can better consider the use reliability and cycle performance of the cylindrical battery cell 6.

[0535] In some embodiments, the first electrode plate 14 is a negative electrode plate 12.

[0536] The first electrode plate 14 is a negative electrode plate 12, the first active material portion 1422 and the second active material portion 1423 include negative active materials, the groove 144 is spaced apart from the second active material portion 1423, the groove 144 does not extend to the second active material portion 1423, and the negative active material of the second active material portion 1423 is not subjected to a grooving operation. The second active material portion 1423 has more negative active materials, which reduces the risk of lithium precipitation of the cylindrical battery cell 6 and is conducive to improving the use performance of the cylindrical battery cell 6.

[0537] In some embodiments, along the axial direction Z of the cylindrical battery cell 6, one end of the first active material portion 1422 is connected with the second active material portion 1423, and the other end of the first active material portion 1422 is not connected with the second active material portion 1423. The surface of the first active material portion 1422 away from the current collector is provided with a groove 144, and along the axial direction Z of the cylindrical battery cell 6, the groove 144 penetrates the end surface of the first active material portion 1422 away from the second active material portion 1423.

[0538] The groove 144 penetrates the end face of the first active material portion 1422 facing away from the second active material portion 1423 and forms an opening, which can directly absorb the electrolyte between the end face of the first active material portion 1422 facing away from the second active material portion 1423 and the shell 20 into the groove 144, improve the impregnation effect of the first tab 14, and be conducive to improving the cycle performance of the cylindrical battery monomer 6.

[0539] In some embodiments, along the axial direction Z of the cylindrical battery monomer 6, one end of the first active material portion 1422 is connected with the second active material portion 1423, and the other end of the first active material portion 1422 is not connected with the second active material portion 1423, and along the axial direction Z of the cylindrical battery monomer 6, the end face of the first active material portion 1422 facing away from the second active material portion 1423 is spaced apart from the groove 144.

[0540] Along the axial direction Z of the cylindrical battery monomer 6, the end face of the first active material portion 1422 facing away from the second active material portion 1423 is spaced apart from the groove 144, so that the groove 144 does not penetrate the end face of the first active material portion 1422 facing away from the second active material portion 1423.

[0541] By adopting the technical scheme of this embodiment, the end face of the first active material portion 1422 facing away from the second active material portion 1423 is spaced apart from the groove 144, which is conducive to improving the structural strength of the end of the first active material portion 1422 facing away from the second active material portion 1423, and can reduce the risk of powder falling or even collapse of the end of the first active material portion 1422 facing away from the second active material portion 1423 due to winding.

[0542] In some embodiments, the distance between the end face of the first active material portion 1422 facing away from the second active material portion 1423 and the groove 144 is s, and 0mm≤s≤20mm.

[0543] In some examples, s can be 0mm, 20mm, or any value between 0mm and 20mm, for example, s can be 0mm, 0.1mm, 0.2mm, 0.5mm, 1mm, 2mm, 2.5mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 15mm, 20mm.

[0544] The design of 0mm≤s≤20mm makes the distance between the end of the first active material portion 1422 facing away from the second active material portion 1423 and the groove 144 closer, and the electrolyte between the end face of the first active material portion 1422 facing away from the second active material portion 1423 and the shell 20 can flow into the groove 144 faster, improving the impregnation effect of the first tab 14 and being conducive to improving the cycle performance of the cylindrical battery monomer 6.

[0545] In some embodiments, 0.1 mm≤s≤8 mm.

[0546] s≥0.1 mm, so that the end surface of the first active material portion 1422 facing away from the second active material portion 1423 is spaced apart from the groove 144, which is conducive to improving the structural strength of the end of the first active material portion 1422 facing away from the second active material portion 1423, and can reduce the risk of the end of the first active material portion 1422 facing away from the second active material portion 1423 from powdering to even collapsing due to winding; the design of s≤8 mm enables the electrolyte between the end surface of the first active material portion 1422 facing away from the second active material portion 1423 and the shell 20 to flow into the groove 144 more quickly, which improves the impregnation effect of the first tab 14 and is conducive to improving the cycle performance of the cylindrical battery cell 6. Therefore, the structural strength of the edge of the first tab 14 and the cycle performance of the cylindrical battery cell 6 can be taken into account.

[0547] In some embodiments, 0.5 mm≤s≤3 mm, which can better take into account the structural strength of the edge of the first tab 14 and the cycle performance of the cylindrical battery cell 6.

[0548] In some embodiments, along the axial direction Z of the cylindrical battery cell 6, both ends of the first active material portion 1422 are connected with the second active material portion 1423, which is conducive to the first tab 14 being able to accommodate more electrolyte at both ends along the axial direction Z of the cylindrical battery cell 6, thereby facilitating the backflow of the electrolyte, improving the impregnation effect of the electrode assembly 10, and improving the cycle performance of the cylindrical battery cell 6.

[0549] Referring to Figure 26 In some embodiments, the first current collector 141 includes a first current collector body 1411 and a first tab 1412 arranged along the axial direction Z of the cylindrical battery cell 6 and connected with each other, at least part of the first current collector body 1411 is covered with the first active material layer 142, and the first tab 1412 is not covered with the first active material layer 142.

[0550] Along the axial direction Z of the cylindrical battery cell 6, the first current collector 141 is divided into two parts, the part covered with the first active material layer 142 is referred to as the first current collector body 1411, and the other part not covered with the first active material layer 142 is referred to as the first tab 1412. The interface between the first tab 1412 and the first current collector body 1411 can be based on the end surface of the first active material layer 142. The first tab 1412 is used for electrical connection with the output electrode, so as to facilitate the input and output of electric energy.

[0551] In some examples, the first current collector body 1411 can be completely covered with the first active material layer 142, or can be partially covered with the first active material layer 142. For example, the side of the first current collector body 1411 facing away from the first tab 1412 is not covered with the first active material layer 142.

[0552] By adopting the technical solution of this embodiment, the first tab 1412 is led out from the end of the first electrode 14 along the axial direction Z of the cylindrical battery cell 6, which facilitates the electrical connection of the first tab 1412 with other components.

[0553] In some embodiments, there are two first active material layers 142, which cover two surfaces of the first current collector 141 along its thickness direction, and at least one first active material layer 142 is provided with a groove 144.

[0554] The first current collector 141 has two surfaces covered with a first active material layer 142 along its thickness direction; one of the two first active material layers 142 has a groove 144 and the other first active material layer 142 does not have a groove 144, or both first active material layers 142 have grooves 144.

[0555] By adopting the technical solution of this embodiment, the arrangement of two first active material layers 142 can increase the amount of active material in the first electrode 14, which is beneficial to increasing the capacity of the cylindrical battery cell 6; in addition, the arrangement of the groove 144 is also more flexible to meet different usage requirements.

[0556] See Figure 25 and Figure 27 As shown, in some embodiments, there are multiple grooves 144, including a first groove 1446 and a second groove 1447 formed along the axial direction Z of the cylindrical battery cell 6. In the two first active material layers 142, one is provided with multiple first grooves 1446 and the other is provided with multiple second grooves 1447. The first grooves 1446 and the second grooves 1447 are staggered along the thickness direction of the first current collector 141.

[0557] Both first active material layers 142 are provided with grooves 144, one of the grooves 144 of the first active material layer 142 is a first groove 1446, and the other groove 144 of the first active material layer 142 is a second groove 1447; the first groove 1446 adopts the same structure as the first groove 1441, and the second groove 1447 adopts the same structure as the first groove 1441.

[0558] The number of first grooves 1446 is multiple, and the number of second grooves 1447 is multiple, in order to improve the wetting effect of the first electrode 14.

[0559] In some examples, along the thickness direction of the first current collector 141, in the adjacent first groove 1446 and the second groove 1447, the projection of the first groove 1446 does not coincide with the projection of the second groove 1447. For example, one second groove 1447 or a plurality of second grooves 1447 can be correspondingly arranged between the adjacent two first grooves 1446.

[0560] By adopting the technical solutions of this embodiment, the two first active material layers 142 are respectively provided with the plurality of first grooves 1446 and the plurality of second grooves 1447, so as to improve the impregnation effect of the two first active material layers 142 and improve the cycle performance of the cylindrical battery monomer 6. In addition, along the thickness direction of the first current collector 141, the first grooves 1446 and the second grooves 1447 are staggered, which is beneficial to improve the structural strength of the first pole piece 14 and improve the use reliability of the cylindrical battery monomer 6.

[0561] In some embodiments, along the winding direction V of the electrode assembly 10, the plurality of first grooves 1446 and the plurality of second grooves 1447 are alternately arranged.

[0562] In some examples, the winding direction V of the electrode assembly 10 can refer to the direction of counterclockwise rotation or clockwise rotation around the winding axis of the electrode assembly 10.

[0563] For example, one second groove 1447 or a plurality of second grooves 1447 can be correspondingly arranged between the adjacent two first grooves 1446.

[0564] By adopting the technical solutions of this embodiment, the plurality of first grooves 1446 and the plurality of second grooves 1447 can be uniformly distributed on the two first active material layers 142, which can improve the uniformity of the distribution of the electrolyte in the cylindrical battery monomer 6 and is beneficial to improve the cycle performance of the cylindrical battery monomer 6.

[0565] In some embodiments, along the winding direction V of the electrode assembly 10, the distance between the adjacent first groove 1446 and the second groove 1447 is C, wherein C≥1.5mm.

[0566] In some examples, along the winding direction V of the electrode assembly 10, the distance C between the adjacent first groove 1446 and the second groove 1447 can refer to the distance between the center surface of the first groove 1446 perpendicular to the winding direction V of the electrode assembly 10 and the center surface of the second groove 1447 perpendicular to the winding direction V of the electrode assembly 10 in the adjacent first groove 1446 and the second groove 1447.

[0567] In some examples, C is 1.5mm or any value greater than 1.5mm, for example, C is 1.5mm, 1.8mm, 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm.

[0568] By adopting the technical solutions of the embodiment, the design of C≥1.5 mm, and the reasonable density of the first groove 1446 and the second groove 1447 can reduce the loss of the active material of the first active material layer 142 and also help to improve the structural strength of the first pole piece 14, and thus the use reliability and energy density of the cylindrical battery monomer 6 can be considered.

[0569] In some embodiments, 1.8 mm≤C≤5 mm, and optionally, 2 mm≤C≤3 mm.

[0570] The design of 1.8 mm≤C≤5 mm, and the reasonable spacing between the adjacent first groove 1446 and the second groove 1447, and the reasonable distribution of the grooves 144 of the two first active material layers 142 help to improve the wettability of the first pole piece 14, reduce the loss of the active material of the first active material layer 142, and also help to improve the structural strength of the first pole piece 14, and thus the cycle performance, use reliability, and energy density of the cylindrical battery monomer 6 can be considered.

[0571] In some embodiments, 2 mm≤C≤3 mm, and the cycle performance, use reliability, and energy density of the cylindrical battery monomer 6 can be better considered.

[0572] Referring to Figure 7 In some embodiments, the first current collector 141 includes a first current collector body 1411 and a first tab 1412 connected to each other, at least part of the first current collector body 1411 is covered with the first active material layer 142, and the first tab 1412 is not covered with the first active material layer 142; and the second current collector 151 includes a second current collector body 1511 and a second tab 1512 connected to each other, at least part of the second current collector body 1511 is covered with the second active material layer 152, and the second tab 1512 is not covered with the second active material layer 152.

[0573] In the axial direction Z of the cylindrical battery monomer 6, the second current collector 151 is divided into two parts, the part covered with the second active material layer 152 is referred to as the second current collector body 1511, and the other part not covered with the second active material layer 152 is referred to as the second tab 1512, and the interface between the second tab 1512 and the second current collector body 1511 can be based on the end face of the second active material layer 152 close to the second tab 1512. The second tab 1512 is used for electrical connection with the output electrode to facilitate the input and output of electric energy.

[0574] In some examples, the second current collector body 1511 can be completely covered with the second active material layer 152, or can be partially covered with the second active material layer 152, for example, the side of the second current collector body 1511 away from the second tab 1512 is not covered with the second active material layer 152.

[0575] By adopting the technical scheme of the embodiment, the first tab 1412 is led out from the first tab 14 at the end along the axial direction Z of the cylindrical battery monomer 6, and the second tab 1512 is led out from the second tab 15 at the end along the axial direction Z of the cylindrical battery monomer 6, so that the input or output of the cylindrical battery monomer 6 is facilitated.

[0576] Referring to Figures 28-30 As shown in the drawings, in some embodiments, the shell 20 includes a housing 21 and an end cover 22, the housing 21 includes a side wall 212 connected with an end wall 211, the side wall 212 surrounds the electrode assembly 10, the end wall 211 and the end cover 22 are oppositely distributed along the axial direction Z of the cylindrical battery monomer 6, and the end cover 22 is sealingly connected to the side wall 212; the end cover 22 is insulatively provided with an electrode terminal 30, the second tab 1512 is electrically connected to the electrode terminal 30, and at least one of the side wall 212 and the end wall 211 is electrically connected to the first tab 1412.

[0577] The end cover 22 is provided with the electrode terminal 30, the electrode terminal 30 is insulatively separated from the end cover 22, and the electrode terminal 30 serves as an output electrode for outputting or inputting electric energy.

[0578] The second tab 1512 can be directly connected to the electrode terminal 30, for example, the second tab 1512 can be directly welded to the electrode terminal 30, and the second tab 1512 can also be welded to the electrode terminal 30 through a conductive member.

[0579] The first tab 1412 can be directly connected to the end wall 211 or indirectly connected to the end wall 211 through the side wall 212 or other components.

[0580] The first tab 1412 can be directly connected to the side wall 212 or indirectly connected to the side wall 212 through the end wall 211 or other components.

[0581] The electrode terminal 30 serves as one exposed electrode of the cylindrical battery monomer 6, and the side wall 212 or the end wall 211 serves as another exposed electrode of the cylindrical battery monomer 6, so that the circuit connection between the cylindrical battery monomers 6 is simpler and more flexible, and the assembly of multiple cylindrical battery monomers 6 into a group is facilitated, and the battery structure is simplified.

[0582] In some embodiments, the electrode terminal 30 is provided with a through hole 31, and the through hole 31 can be used for injecting electrolyte.

[0583] In some embodiments, the cylindrical battery monomer 6 further includes a cover plate 40 connected to the electrode terminal 30 and used for separating the through hole 31 from the external space of the cylindrical battery monomer 6.

[0584] In some embodiments, the shell 20 comprises a casing 21 and an end cover 22, the casing 21 comprises a side wall 212 connected with an end wall 211, the side wall 212 surrounds the electrode assembly 10, the end wall 211 and the end cover 22 are oppositely distributed along the axial direction Z of the cylindrical battery cell 6, and the end cover 22 is sealingly connected to the side wall 212; the end wall 211 is provided with the electrode terminal 30, the second tab 1512 is electrically connected to the electrode terminal 30, and at least one of the end cover 22 and the side wall 212 is electrically connected to the first tab 1412.

[0585] The end wall 211 is provided with the electrode terminal 30, the electrode terminal 30 is insulated from the end wall 211, and the electrode terminal 30 serves as an output electrode for outputting or inputting electric energy.

[0586] The second tab 1512 can be directly connected to the electrode terminal 30, for example, the second tab 1512 can be directly welded to the electrode terminal 30, and the second tab 1512 can also be welded to the electrode terminal 30 through a conductive member.

[0587] The first tab 1412 can be directly connected to the end cover 22 or indirectly connected to the end wall 211 through the side wall 212 or other components.

[0588] The first tab 1412 can be directly connected to the side wall 212 or indirectly connected to the side wall 212 through the end cover 22 or other components.

[0589] The electrode terminal 30 serves as one exposed electrode of the cylindrical battery cell 6, and the side wall 212 or the end cover 22 serves as another exposed electrode of the cylindrical battery cell 6, so that the circuit connection between the cylindrical battery cells 6 is simpler and more flexible, which is conducive to the assembly of multiple cylindrical battery cells 6 into a group and simplifies the battery structure.

[0590] In some embodiments, the cylindrical battery cell 6 further comprises a first current collecting member 60 and a second current collecting member 70; the first tab 1412 and the second tab 1512 are respectively located at two ends of the electrode assembly 10 along the axial direction Z of the cylindrical battery cell 6, and the second tab 1512 is located on the side of the electrode assembly 10 close to the electrode terminal 30; the second current collecting member 70 is electrically connected between the second tab 1512 and the electrode terminal 30; the electrode terminal 30 is insulated and arranged on the end cover 22, the first current collecting member 60 is located between the first tab 1412 and the end wall 211, the first current collecting member 60 is electrically connected to the first tab 1412, and at least one of the side wall 212 and the end wall 211 is electrically connected to the first current collecting member 60.

[0591] The second tab 1512 and the first tab 1412 are located at two ends of the electrode assembly 10, which can reduce the risk of short circuit of the cylindrical battery cell 6.

[0592] The second current collecting member 70 can serve as an adapter to facilitate the electrical connection between the second tab 1512 and the electrode terminal 30.

[0593] For example, the second current collecting member 70 is welded to the second tab 1512, and the second current collecting member 70 is welded to the electrode terminal 30.

[0594] In some examples, the second current collecting member 70 is a circular ring.

[0595] The first current collecting member 60 can serve as an adapter to facilitate the electrical connection between the first tab 1412 and at least one of the side wall 212 and the end wall 211.

[0596] For example, the first current collecting member 60 is welded to the first tab 1412, the second current collecting member 70 is welded to the side wall 212, or the first current collecting member 60 is welded to the end wall 211.

[0597] In some embodiments, the cylindrical battery cell 6 further includes a first current collecting member 60 and a second current collecting member 70; the first tab 1412 and the second tab 1512 are respectively located at two ends of the electrode assembly 10 along the axial direction Z of the cylindrical battery cell 6, and the second tab 1512 is located at a side of the electrode assembly 10 close to the electrode terminal 30; the second current collecting member 70 is electrically connected between the second tab 1512 and the electrode terminal 30; the electrode terminal 30 is insulatively arranged on the end wall 211, the first current collecting member 60 is located between the first tab 1412 and the end cover 22, the first current collecting member 60 is electrically connected to the first tab 1412, and at least one of the side wall 212 and the end cover 22 is electrically connected to the first current collecting member 60.

[0598] The first current collecting member 60 can serve as an adapter to facilitate the electrical connection between the first tab 1412 and at least one of the side wall 212 and the end cover 22.

[0599] For example, the first current collecting member 60 is welded to the first tab 1412, the second current collecting member 70 is welded to the side wall 212, or the first current collecting member 60 is welded to the end cover 22.

[0600] In some embodiments, the electrode terminal 30 is insulatively arranged on the end wall 211; the side wall 212 is provided with a protruding portion 2121 protruding inwardly, and along the axial direction of the cylindrical battery cell 6, the protruding portion 2121 is located at a side of the first tab 1412 facing the end cover 22; the second current collecting member 70 includes a first connecting portion 61, a second connecting portion 62, and a third connecting portion 63, the second connecting portion 62 is connected between the first connecting portion 61 and the third connecting portion 63; the first connecting portion 61 is connected to the first tab 1412, at least part of the third connecting portion 63 is located between the protruding portion 2121 and the end cover 22, and the third connecting portion 63 is connected to a side surface of the protruding portion 2121 facing away from the first tab 1412.

[0601] The side wall 212 is provided with a protrusion 2121 protruding inwardly. Exemplarily, the protrusion 2121 can be a solid structure or a hollow structure.

[0602] At least part of the protrusion 2121 is located between the end cover 22 and the first tab 1412 in the axial direction Z of the cylindrical battery cell 6.

[0603] The protrusion 2121 overlaps the first tab 1412 in the axial direction Z of the cylindrical battery cell 6, which can limit the movement of the first tab 1412 along the axial direction Z of the cylindrical battery cell 6 when the cylindrical battery cell 6 is subjected to external impact, thereby reducing the risk of disconnection between the first tab 1412 and the first current collecting member 60.

[0604] The first current collecting member 60 includes a first connecting portion 61, a second connecting portion 62, and a third connecting portion 63. The first connecting portion 61 is welded to the first tab 1412. The third connecting portion 63 is connected to the protrusion 2121. Exemplarily, the third connecting portion 63 can be welded to the protrusion 2121. Alternatively, the third connecting portion 63 can be crimped to the protrusion 2121. The first connecting portion 61 can be welded to the first tab 1412.

[0605] At least part of the third connecting portion 63 is located between the protrusion 2121 and the end cover 22. The third connecting portion 63 is connected to the side of the protrusion 2121 facing the end cover 22, so that the first current collecting member 60 can be assembled through the end cover 22, facilitating the installation of the first current collecting member 60. In addition, the protrusion 2121 also functions as a limiting portion for the third connecting portion 63, improving the installation stability of the first current collecting member 60, and improving the connection reliability between the first current collecting member 60 and the first tab 1412 and between the first current collecting member 60 and the protrusion 2121, thereby improving the use reliability of the cylindrical battery cell 6.

[0606] In some embodiments, the third connecting portion 63 is welded to the protrusion 2121.

[0607] In some embodiments, the outer side of the side wall 212 is provided with a recess 2122 corresponding in position to the protrusion 2121. Exemplarily, after the electrode assembly 10 is installed into the housing 21, the protrusion 2121 protruding inwardly is formed by extruding the side wall 212 from the outer side.

[0608] In some embodiments, the side wall 212 further includes a crimping portion 2123 extending from the protrusion 2121 away from one end of the end wall 211 and arranged around the end cover 22.

[0609] A portion of the crimping portion 2123 is bent and arranged to form a flange structure, and a portion of the end cover 22 is located between the flange structure and the protrusion 2121 in the axial direction Z of the cylindrical battery cell 6. 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 of the cylindrical battery cell 6.

[0610] In some embodiments, the cylindrical battery cell 6 further comprises an insulating member 80 arranged between the side wall 212 and the end cover 22 and insulating the end cover 22 from the side wall 212.

[0611] In some embodiments, a portion of the insulating member 80 is located between the third connecting portion 63 and the end cover 22 to insulate the first current collecting member 60 from the end cover 22.

[0612] In some embodiments, a battery device 2 is provided, comprising a plurality of the cylindrical battery cell 6 described above.

[0613] By adopting the technical scheme of this embodiment, the cylindrical battery cell 6 has good cycle performance, good use reliability and high energy density, which is conducive to improving the use performance and service life of the battery device 2.

[0614] In some embodiments, an electric device is provided, comprising the cylindrical battery cell 6 described above or the battery device 2 described above, and the battery cell or the battery device 2 is used to store or provide electric energy.

[0615] By adopting the technical scheme of this embodiment, the cylindrical battery cell 6 has good cycle performance, good use reliability and high energy density, the battery device 2 has good use performance and long service life, which is conducive to improving the use performance and service life of the electric device.

[0616] Referring to Figures 3-9 As shown in the accompanying drawings, the embodiments of the present application provide a cylindrical battery cell 6, which comprises a housing 20, an electrode assembly 10, an electrode terminal 30, a first current collecting member 60 and a second current collecting member 70.

[0617] The housing 20 comprises a shell 21 and an end cover 22, the shell 21 comprises an integral side wall 212 and an end wall 211, the end wall 211 and the end cover 22 are opposite in the axial direction Z of the cylindrical battery cell 6, and the end cover 22 is welded to the side wall 212.

[0618] The electrode terminal 30 is arranged insulatively on the end wall 211.

[0619] At least a portion of the electrode assembly 10 is accommodated in the housing 20. The electrode assembly 10 comprises a first pole piece 14, a second pole piece 15 and a separator 13, the second pole piece 15, the first pole piece 14 and the separator 13 are arranged in a roll shape, and the separator 13 is used to separate the second pole piece 15 and the first pole piece 14.

[0620] The first electrode sheet 14 includes a first current collector 141 and a first active material layer 142 covering a surface of the first current collector 141. The second electrode sheet 15 includes a second current collector 151 and a second active material layer 152 covering a surface of the second current collector 151. A portion of the first current collector 141 not covered with the first active material layer 142 forms a first tab 1412, and a portion of the second current collector 151 not covered with the second active material layer 152 forms a second tab 1512. The first current collecting member 60 connects the first tab 1412 and the side wall 212, and the second current collecting member 70 connects the electrode terminal 30 and the second tab 1512.

[0621] The first active material layer 142 and the second active material layer 152 form m gap-wound turns therebetween, m ≥ 30, m being a natural number; the innermost one of the gap-wound turns is the first gap-wound turn; and the average of the radial dimensions of the m-13th to m-5th gap-wound turns is greater than the average of the radial dimensions of the 5th to 13th gap-wound turns.

[0622] The above description of the various embodiments tends to emphasize differences between the various embodiments, and the same or similar parts can be referred to each other, and will not be described herein for the sake of brevity.

[0623] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement to part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should be covered in the scope of the claims and the description of the present application. Especially, as long as there is no structural conflict, each technical feature mentioned in each embodiment can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A cylindrical battery cell having a housing diameter of greater than or equal to 40 mm, characterized in that, The cylindrical battery cell comprises: an electrode assembly in a wound structure, at least part of the electrode assembly being accommodated in the outer shell, the electrode assembly comprising a separator and first and second polar plates of opposite polarity, at least part of the separator being located between the first and second polar plates; the first polar plate comprises a first current collector and a first active material layer, at least part of the first active material layer being connected to at least part of an area of at least one surface of the first current collector in the thickness direction of the first current collector, at least part of the first active material layer being located between the first current collector and the separator; the second polar plate comprises a second current collector and a second active material layer, at least part of the second active material layer being connected to at least part of an area of at least one surface of the second current collector in the thickness direction of the second current collector, at least part of the second active material layer being located between the second current collector and the separator; m gaps are formed between the first active material layer and the second active material layer, m≥30, m being a natural number; the innermost one of the gap winding turns is the first gap winding turn, and the average value of the radial dimensions of the m-13th to m-5th gap winding turns is greater than the average value of the radial dimensions of the 5th to 13th gap winding turns.

2. The cylindrical battery cell of claim 1, wherein: The gap winding turns comprise first gap sub-turns and second gap sub-turns, the first gap sub-turns being located between the first active material layer and the separator, and the second gap sub-turns being located between the second active material layer and the separator.

3. The cylindrical battery cell of claim 1, wherein: The radial dimension of the first gap winding turn is smaller than the radial dimension of the mth gap winding turn.

4. The cylindrical battery cell according to any one of claims 1 to 3, characterized in that: The m gap winding turns are divided into j groups of gap winding turns in the order from the inside to the outside of the electrode assembly. The innermost group of gap winding turns is the first group of gap winding turns, each group of gap winding turns in the first group to the j-1th group comprises 9 gap winding turns, 1≤m-9*(j-1)≤9, j being a natural number, and the average value of the radial dimensions of the first group to the j-1th group of gap winding turns is arranged in ascending order.

5. The cylindrical battery cell according to any one of claims 1 to 3, characterized in that: The first polar plate winding arrangement forms a plurality of first polar plate winding turns, the first current collector comprises a first current collector winding turn located in the first polar plate winding turn, and the first active material layer comprises a first active material winding turn located in the first polar plate winding turn, the first active material winding turn having a first winding surface facing away from the corresponding first current collector winding turn; the first winding surface of at least one first polar plate winding turn is provided with a groove.

6. The cylindrical battery cell of claim 5, wherein: The number of grooves is a plurality, and the plurality of grooves comprises at least one first groove formed in the axial direction of the cylindrical battery cell.

7. The cylindrical battery cell of claim 6, wherein: The number of first grooves is a plurality, and the plurality of first grooves are arranged at intervals in the winding direction of the electrode assembly, and the distance between adjacent two first grooves is arranged in ascending order.

8. The cylindrical battery cell of claim 6, wherein: The thickness of the first active material layer is t, and the groove depth of the first groove is h, wherein 0.05≤h / t≤0.

84.

9. The cylindrical battery cell of claim 8, wherein: 0.08≤h / t≤0.

8.

10. The cylindrical battery cell of claim 8, wherein 0.1≤h / t≤0.

5.

11. The cylindrical battery cell of claim 6, wherein: The groove depth of the first groove is h, and 0μm 12. The cylindrical battery cell of claim 11, wherein: 6 μm≤h≤30 μm.

13. The cylindrical battery cell of claim 6, wherein: The first groove has a groove width w, wherein 30 μm≤w≤1000 μm.

14. The cylindrical battery cell of claim 13, wherein: 50 μm≤w≤500 μm.

15. The cylindrical battery cell of claim 14, wherein: 80 μm≤w≤120 μm.

16. The cylindrical battery cell of claim 6, wherein: The first groove has a groove width w and a groove depth h, wherein 0.05≤h / w≤1.

17. The cylindrical battery cell of claim 16, wherein: 0.1≤h / w≤0.

5.

18. The cylindrical battery cell of claim 6, wherein: In the axial direction of the cylindrical battery cell, the size of the first active material layer is L, the groove depth of the first groove is h, 5*10 -5 ≤h / L≤5*10 -4 .

19. The cylindrical battery cell of claim 6, wherein: In the axial direction of the cylindrical battery cell, the first active material layer has a size L, and the first groove has a groove depth h, wherein L≥60 mm and h≥6 μm.

20. The cylindrical battery cell of claim 6, wherein: In the axial direction of the cylindrical battery cell, the first groove has a size l, and the first active material layer has a size L, wherein 0.8≤l / L≤1.

21. The cylindrical battery cell of claim 20, wherein: 0.9≤l / L≤0.98。 22. The cylindrical battery cell of claim 20, wherein: 60 mm≤L≤330 mm.

23. The cylindrical battery cell of claim 22, wherein: 70 mm≤L≤200 mm.

24. The cylindrical battery cell of claim 6, wherein: The first groove comprises a first groove segment and a second groove segment connected in communication, the second groove segment is connected to the first groove segment at least at one end in the axial direction of the cylindrical battery cell, the groove depth of the first groove segment is greater than the groove depth of the second groove segment, and / or the groove width of the first groove segment is greater than the groove width of the second groove segment.

25. The cylindrical battery cell of claim 24, wherein: In the direction of the first groove segment pointing to the second groove segment, the groove depth of the second groove segment is arranged to decrease from the first groove segment; and / or in the direction of the first groove segment pointing to the second groove segment, the groove width of the second groove segment is arranged to decrease from the first groove segment.

26. The cylindrical battery cell of claim 6, wherein: The first groove comprises a plurality of sub-segments, and the plurality of sub-segments are distributed at intervals in the axial direction of the cylindrical battery cell.

27. The cylindrical battery cell of claim 26, wherein: In the axial direction of the cylindrical battery cell, the interval between two adjacent sub-segments is d, wherein 0.1 mm≤d≤1 mm.

28. The cylindrical battery cell of claim 27, wherein: 0.3 mm≤d≤0.6 mm.

29. The cylindrical battery cell of claim 26, wherein: In the winding direction of the electrode assembly, in two adjacent first grooves, the sub-segment of one of the first grooves is arranged to be staggered with at least part of the sub-segment of the other first groove.

30. The cylindrical battery cell of claim 5, wherein: The number of the grooves is a plurality, and the plurality of grooves form a plurality of groups of the grooves, each group of the grooves comprises a plurality of intersecting grooves, and the plurality of groups of the grooves are arranged at intervals in the winding direction of the electrode assembly.

31. The cylindrical battery cell of claim 5, wherein: The number of the first electrode sheet winding turns is n, n≥30, n is a natural number, the innermost first electrode sheet winding turn is the first first electrode sheet winding turn, and at least one of the first 10 first electrode sheet winding turns is provided with the groove.

32. The cylindrical battery cell of claim 5, wherein: The number of the first electrode sheet winding turns is n, n≥30, n is a natural number, the innermost first electrode sheet winding turn is the first first electrode sheet winding turn, and at least the first first electrode sheet winding turn is not provided with the groove.

33. The cylindrical battery cell of claim 32, wherein: At least the first 3 first electrode sheet winding turns are not provided with the groove.

34. The cylindrical battery cell of claim 32, wherein: The electrode assembly is provided with a center hole, and the first first electrode sheet winding turn is closest to the center hole compared with other first electrode sheet winding turns.

35. The cylindrical battery cell of claim 5, wherein: The number of the first electrode sheet winding turns is n, n≥30, n is a natural number, the innermost first electrode sheet winding turn is the first first electrode sheet winding turn, and at least the last 2 first electrode sheet winding turns are not provided with the groove.

36. The cylindrical battery cell of claim 35, wherein: At least the last 10 first electrode sheet winding turns are not provided with the groove.

37. The cylindrical battery cell of claim 5, wherein: The number of the first pole piece winding turns is n, n>30, n is a natural number; the innermost one of the first pole piece winding turns is the first first pole piece winding turn; The first f first pole piece winding turns are not provided with the groove, the last q first pole piece winding turns are not provided with the groove; all the first pole piece winding turns between the fth first pole piece winding turn and the last q first pole piece winding turn are provided with the groove, f+q<n, f and q are positive integers.

38. The cylindrical battery cell of any one of claims 31-37, wherein: 30≤n≤80。 39. The cylindrical battery cell of claim 38, wherein: 60≤n≤75。 40. The cylindrical battery cell of any one of claims 31-39, wherein: The number of the first pole piece winding turns provided with the groove is v, 0.23≤v / n≤1, v and n are positive integers.

41. The cylindrical battery cell of claim 40, wherein: 0.3≤v / n≤0.

7.

42. The cylindrical battery cell of claim 5, wherein: The first pole piece has a first winding end, the second pole piece has a second winding end, the innermost first pole piece winding turn is the first first pole piece winding turn, and the second winding end is located between the second last first pole piece winding turn and the last first pole piece winding turn. The positions corresponding to the end surface of the first winding end of the second last first pole piece winding turn and the last first pole piece winding turn are not provided with the groove. And / or, the positions corresponding to the end surface of the second winding end of the second last first pole piece winding turn and the last first pole piece winding turn are not provided with the groove.

43. The cylindrical battery cell of claim 42, wherein: The second last first pole piece winding turn and the last first pole piece winding turn are provided with the groove, and the groove is arranged away from at least one of the end surface of the first winding end and the end surface of the second winding end. Or, the second last first pole piece winding turn and the last first pole piece winding turn are not provided with the groove.

44. The cylindrical battery cell of claim 5, wherein: The first pole piece has a first winding start end, the second pole piece has a second winding start end, the innermost first pole piece winding turn is the first first pole piece winding turn, and the second winding start end is located between the first two first pole piece winding turns. The positions corresponding to the end surface of the first winding start end of the first two first pole piece winding turns are not provided with the groove. And / or, the positions corresponding to the end surface of the second winding start end of the first two first pole piece winding turns are not provided with the groove.

45. The cylindrical battery cell of claim 44, wherein: The first two first pole piece winding turns are provided with the groove, and the groove is arranged away from at least one of the end surface of the first winding start end and the end surface of the second winding start end. Or, the first two first pole piece winding turns are not provided with the groove.

46. The cylindrical battery cell of claim 42, wherein: The first pole piece is a negative pole piece, and the second pole piece is a positive pole piece; or, the second pole piece is a negative pole piece, and the first pole piece is a positive pole piece.

47. The cylindrical battery cell of claim 5, wherein: The first active material layer comprises a first active material part and a second active material part arranged along the axial direction of the cylindrical battery monomer, the first active material part is connected with the second active material part at least at one end along the axial direction of the cylindrical battery monomer, and the thickness of the second active material part is smaller than the thickness of the first active material part.

48. The cylindrical battery cell of claim 47, wherein: In the direction of the first active material part pointing to the second active material part, the thickness of the second active material part shows a decreasing trend.

49. The cylindrical battery cell of claim 47, wherein: The first active material part has a first surface facing away from the first current collector, and the second active material part has a second surface facing away from the first current collector, and the second surface is closer to the first current collector than the first surface.

50. The cylindrical battery cell of claim 47, wherein: The first active material part is provided with the groove, and the second active material part is arranged at a distance from the groove along the axial direction of the cylindrical battery monomer.

51. The cylindrical battery cell of claim 50, wherein: The distance between the second active material part and the groove along the axial direction of the cylindrical battery monomer is S1, wherein 0mm < S1 ≤ 18mm.

52. The cylindrical battery cell of claim 50, wherein: 2mm ≤ S1 ≤ 8mm.

53. The cylindrical battery cell of claim 50, wherein: The first pole piece is a negative pole piece.

54. The cylindrical battery cell of claim 47, wherein: One end of the first active material part is connected with the second active material part along the axial direction of the cylindrical battery monomer, and the other end of the first active material part is not connected with the second active material part, the surface of the first active material part away from the current collector is provided with the groove, and the groove penetrates the end surface of the first active material part away from the second active material part along the axial direction of the cylindrical battery monomer; or the end surface of the first active material part away from the second active material layer is arranged at a distance from the groove along the axial direction of the cylindrical battery monomer.

55. The cylindrical battery cell of claim 54, wherein: The distance between the end surface of the first active material part away from the second active material part and the groove is s, wherein 0mm ≤ s ≤ 20mm.

56. The cylindrical battery cell of claim 55, wherein: 0.1mm ≤ s ≤ 8mm.

57. The cylindrical battery cell of claim 56, wherein: 0.5mm ≤ s ≤ 3mm.

58. The cylindrical battery cell of claim 47, wherein: Both ends of the first active material part are connected with the second active material part along the axial direction of the cylindrical battery monomer.

59. The cylindrical battery cell of claim 47, wherein: The first current collector comprises a first current collector main body and a first tab arranged and connected along the axial direction of the cylindrical battery monomer, and at least part of the first current collector main body is covered with the first active material layer, and the first tab is not covered with the first active material layer.

60. The cylindrical battery cell of claim 5, wherein: The number of the first active material layers is two, two first active material layers are respectively covered on two surfaces of the first current collector along the thickness direction of the first current collector, and at least one first active material layer is provided with the groove.

61. The cylindrical battery cell of claim 60, wherein: The number of the grooves is multiple, the multiple grooves comprise first grooves and second grooves formed along the axial direction of the cylindrical battery monomer, one of the two first active material layers is provided with multiple first grooves, and the other is provided with multiple second grooves; the first grooves and the second grooves are arranged at a distance along the thickness direction of the first current collector.

62. The cylindrical battery cell of claim 61, wherein: Along the winding direction of the electrode assembly, the multiple first grooves and the multiple second grooves are arranged alternately.

63. The cylindrical battery cell of claim 62, wherein: Along the winding direction of the electrode assembly, the distance between adjacent first grooves and second grooves is C, wherein C ≥ 1.5mm.

64. The cylindrical battery cell of claim 63, wherein: 1.8mm ≤ C ≤ 5mm.

65. The cylindrical battery cell of claim 64, wherein: 2mm ≤ C ≤ 3mm.

66. The cylindrical battery cell of any one of claims 1-3, wherein: The first current collector comprises a first current collector main body and a first tab arranged and connected along the axial direction of the cylindrical battery monomer, and at least part of the first current collector main body is covered with the first active material layer, and the first tab is not covered with the first active material layer; The second current collector comprises a second current collector main body and a second tab arranged and connected, at least part of the second current collector main body is covered with the second active material layer, and the second tab is not covered with the second active material layer.

67. The cylindrical battery cell of claim 66, wherein: The shell comprises a shell body and an end cover, the shell body comprises connected side walls and end walls, the side walls surround the electrode assembly, the end walls and the end cover are distributed in opposite directions along the axial direction of the cylindrical battery monomer, and the end cover is sealingly connected to the side walls; The end cover is insulated and provided with an electrode terminal, the second tab is electrically connected to the electrode terminal, and at least one of the side walls and the end walls is electrically connected to the first tab; Alternatively, the end wall is insulated and provided with an electrode terminal, the second tab is electrically connected to the electrode terminal, and at least one of the end cover and the side walls is electrically connected to the first tab.

68. The cylindrical battery cell of claim 67, wherein: The cylindrical battery monomer further comprises a first current collecting member and a second current collecting member; the first tab and the second tab are respectively located at two ends of the electrode assembly along the axial direction of the cylindrical battery monomer, and the second tab is located on the side of the electrode assembly close to the electrode terminal; the second current collecting member is electrically connected between the second tab and the electrode terminal; The electrode terminal is insulated and arranged on the end cover, the first current collecting member is located between the first tab and the end wall, the first current collecting member is electrically connected to the first tab, and at least one of the side walls and the end wall is electrically connected to the first current collecting member; Alternatively, the electrode terminal is insulated and arranged on the end wall, the first current collecting member is located between the first tab and the end cover, the first current collecting member is electrically connected to the first tab, and at least one of the side walls and the end cover is electrically connected to the first current collecting member.

69. The cylindrical battery cell of claim 68, wherein: The electrode terminal is insulated and arranged on the end wall; The side wall is provided with a protruding portion protruding inward, and along the axial direction of the cylindrical battery monomer, the protruding portion is located on the side of the first tab facing the end cover; The second current collecting member comprises a first connecting portion, a second connecting portion and a third connecting portion, the second connecting portion is connected between the first connecting portion and the third connecting portion; the first connecting portion is connected to the first tab, at least part of the third connecting portion is located between the protruding portion and the end cover, and the third connecting portion is connected to the side of the protruding portion away from the first tab.

70. A battery device, comprising: A plurality of cylindrical battery monomers according to any one of claims 1-69 are included.

71. An electrical device, comprising: A cylindrical battery monomer according to any one of claims 1-69 or a battery device according to claim 70 is used for storing or providing electric energy.

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