Battery cell, cylindrical battery and electrical device

Abstract

A battery cell (100), a cylindrical battery and an electrical device. The battery cell (100) comprises a battery cell winding body (10), the battery cell winding body (10) comprising a first electrode sheet (11), a second electrode sheet (13) and a separator which are wound. Each electrode sheet comprises an electrode sheet body (20) and an active substance layer (25), the electrode sheet body (20) comprising a coating area (23) and an empty foil area (24) connected to the side of the coating area (23) in the winding axial direction, and the active material layer (25) covering the coating area (23). At least part of the empty foil area (24) is suitable for bending to form a tab part (40), and the tab part (40) comprises a plurality of first tab groups (32) arranged at intervals in the winding circumferential direction.

Description

Battery cells, cylindrical batteries and electrical equipment

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application is based on the Chinese patent application with application number 202322684707.6 and application date September 28, 2023, and claims the priority of the Chinese patent application. The entire content of the Chinese patent application is hereby introduced into this application as a reference. Technical Field

[0003] The present application relates to the field of battery technology, and in particular to a battery cell, a cylindrical battery, and an electrical device. Background Art

[0004] In the related art, during the preparation process of cylindrical batteries using full-tab cells, after the pole sheets are stacked and wound, the pole tabs are easily subjected to collision and extrusion during the bending and smoothing process, which can easily generate metal chips and cause a short circuit risk.

[0005] Summary of the Invention

[0006] The present application aims to solve at least one of the technical problems existing in the prior art. To this end, one object of the present application is to provide a battery cell in which, by configuring the tab portion as a plurality of first tab groups spaced apart along the winding circumference, during the process of bending and smoothing at least a portion of the empty foil region to form the tab portion, collision and compression between the two adjacent first tab groups, which could generate metal chips, can be avoided because the first tab groups are spaced apart from each other, thereby reducing the risk of short circuits caused by the bending and smoothing of the tab portion.

[0007] The present application proposes a cylindrical battery having the above-mentioned battery cell.

[0008] The present application also proposes an electrical device having the cylindrical battery.

[0009] According to the battery cell of the first aspect embodiment of the present application, which is used for a cylindrical battery, the battery cell includes: a battery cell winding body, including a first pole piece, a second pole piece and an isolation membrane that are wound together, the polarities of the first pole piece and the second pole piece are opposite, the isolation membrane is arranged between the first pole piece and the second pole piece, the first pole piece and / or the second pole piece include a pole piece body and an active material layer, the pole piece body includes a coating area and a hollow foil area connected to one side of the coating area along the axial direction of winding, the active material layer covers the coating area, and at least part of the hollow foil area is suitable for bending to form a pole ear portion, and the pole ear portion includes a plurality of first pole ear groups arranged at intervals along the winding circumference.

[0010] According to the battery cell of the embodiment of the present application, by arranging the pole ear portion into a plurality of first pole ear groups spaced apart along the winding circumferential direction, in the process of bending and smoothing at least a portion of the empty foil area to form the pole ear portion, since the two adjacent first pole ear groups are spaced apart, collision and extrusion between the two adjacent first pole ear groups to generate metal chips can be avoided, thereby reducing the risk of short circuit caused by the bending and smoothing of the pole ear portion.

[0011] According to some embodiments of the present application, the outer contour of the orthographic projection of the first tab group in the winding axial direction is fan-shaped.

[0012] According to some embodiments of the present application, the number of the first tab groups is 5 to 16.

[0013] According to some embodiments of the present application, the distance between adjacent first tab groups ranges from 0.5 mm to 8 mm.

[0014] According to some embodiments of the present application, on the same winding turn, the circumferential size of the first electrode tab group is greater than the circumferential spacing between adjacent first electrode tab groups.

[0015] According to some embodiments of the present application, spacing grooves are formed between adjacent first tab groups.

[0016] According to some optional embodiments of the present application, along the winding axial direction, the two sides of the interval opposite to each other in the circumferential direction of the battery cell winding body are respectively a first side and a second side, and the extension line of the first side is parallel to or at an angle to the extension line of the second side.

[0017] According to some embodiments of the present application, the two opposite sides of the first tab group in the winding circumferential direction are respectively the third side and the fourth side, and the extension line of the third side is set at an angle with the extension line of the fourth side, and the angle range is 22.5° to 80°.

[0018] According to some embodiments of the present application, the pole tab portion includes a plurality of second pole tab groups arranged at intervals along the winding circumferential direction, the second pole tab groups and the first pole tab groups are alternately arranged in the winding circumferential direction, and a bending gap is formed between adjacent second pole tab groups and first pole tab groups.

[0019] According to some optional embodiments of the present application, on the same winding coil, the circumferential dimension of the second tab group is greater than the circumferential dimension of the bending gap.

[0020] According to some optional embodiments of the present application, on the same winding coil, the two opposite sides of the second tab group in the circumferential direction of the battery cell winding are respectively the fifth side and the sixth side, and the extension line of the fifth side is parallel to or at an angle to the extension line of the sixth side.

[0021] According to some optional embodiments of the present application, at least one end of the first electrode tab group along the winding circumferential direction is arranged on a side of the adjacent second electrode tab group away from the coating area.

[0022] According to some embodiments of the present application, the empty foil area includes a buffer zone and a tab area, the buffer zone is connected between the tab area and the coating area, there is a bending line between the buffer zone and the tab area, and the tab area is suitable for bending from the bending line to form the tab portion.

[0023] According to some embodiments of the present application, in the axial direction of the winding, the height of the empty foil area ranges from 3 mm to 10 mm.

[0024] According to some embodiments of the present application, a portion of the empty foil area close to the winding axis is formed with an avoidance gap, and the avoidance gap constitutes a tab-free area. At least a portion of the empty foil area is bent toward the winding axis to form the tab portion.

[0025] According to some embodiments of the present application, the battery cell further includes a current collecting disk, which is provided on a side of the electrode tab portion away from the coating area, and the current collecting disk is electrically connected to the first electrode tab group.

[0026] According to some optional embodiments of the present application, the current collecting plate includes a tab connecting portion and a flexible buffer portion, the tab connecting portion is electrically connected to the first tab group, and the flexible buffer portion can be deformed in the winding axial direction.

[0027] According to some optional embodiments of the present application, a bypass opening is formed on the collecting disc, and in the winding axial direction, at least a portion of the flexible buffer portion is opposite to the bypass opening.

[0028] According to some optional embodiments of the present application, the flexible buffer portion includes an intermediate spring sheet and a plurality of elastic connecting sheets arranged at intervals along the circumference of the current collecting disk, the intermediate spring sheet is located in the middle of the current collecting disk, one end of the elastic connecting sheet is connected to the intermediate spring sheet, and the other end of the elastic connecting sheet extends in a direction away from the center of the current collecting disk and is connected to the pole ear connecting portion. In the winding axial direction, the elastic connecting sheet and the intermediate spring sheet are both opposite to the avoidance opening.

[0029] According to some optional embodiments of the present application, the width of the elastic connecting piece in the circumferential direction of the collecting plate ranges from 4 mm to 10 mm.

[0030] According to some optional embodiments of the present application, the avoidance passage includes an intermediate passage area and a plurality of branch passage areas connected to the intermediate passage area, and the plurality of branch passage areas are located on the outer peripheral side of the intermediate passage area and are arranged at circumferential intervals along the collecting disk; wherein, in the winding axial direction, the intermediate spring sheet is opposite to the intermediate passage area, the elastic connecting sheet is opposite to the branch passage area, the pole ear connection portion includes a plurality of sub-pole ear connection portions arranged at circumferential intervals along the collecting disk, and the branch passage area is located between adjacent sub-pole ear connection portions.

[0031] According to some optional embodiments of the present application, the distance between the radial outer edge of the branch outlet area and the outer edge of the collecting plate is in the range of 3 mm to 12 mm.

[0032] According to some optional embodiments of the present application, in the winding axial direction, at least a portion of the branch opening area is opposite to the area between two adjacent first tab groups.

[0033] The cylindrical battery according to the second embodiment of the present application includes: the battery cell according to the first embodiment of the present application.

[0034] According to the cylindrical battery of the embodiment of the present application, by providing the above-mentioned battery cell, during the process of bending and smoothing to form the pole ear portion, collision and extrusion to generate metal chips can be avoided, thereby reducing the risk of short circuit caused by the bending and smoothing of the pole ear portion.

[0035] An electrical device according to an embodiment of the third aspect of the present application includes: a cylindrical battery according to an embodiment of the second aspect of the present application.

[0036] According to the electrical equipment of the embodiment of the present application, by providing the above-mentioned cylindrical batteries, during the process of manufacturing the cylindrical batteries, in the process of bending and smoothing to form the pole ear portion, collision and extrusion to generate metal chips can be avoided, thereby reducing the risk of short circuit caused by the bending and smoothing of the pole ear portion.

[0037] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become obvious from the description below, or will be learned through practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0039] FIG1 is a schematic diagram of an expanded electrode sheet of a battery cell according to some embodiments of the present application;

[0040] FIG2 is a schematic diagram of a battery cell wound body according to some embodiments of the present application;

[0041] FIG3 is a schematic diagram of the first process of processing the battery cell wound body of the battery cell in FIG2 , showing a plurality of spacing grooves formed at the locations of the tab clusters;

[0042] FIG4 is a schematic diagram of a battery cell wound body according to other embodiments of the present application;

[0043] FIG5 is a schematic diagram of the first processing process of the battery cell wound body of the battery cell in FIG4 , showing two bending gaps cut and formed at the location of the tab cluster by the cutting tool;

[0044] FIG6 is a second schematic diagram of the processing process of the battery cell wound body of the battery cell in FIG4 , showing a plurality of bending gaps cut and formed at the locations of the tab clusters;

[0045] FIG7 is a third schematic diagram of the processing process of the battery cell wound body of the battery cell in FIG6 , showing that the second tab group is bent toward the direction close to the center hole and smoothed;

[0046] FIG8 is a schematic diagram of the assembly of the battery cell wound body and the current collecting disk of the battery cell in FIG7 ;

[0047] FIG9 is a partial enlarged view of point A in FIG8 .

[0048] Reference numerals: 100, battery cell; 10, battery cell wound body; 11, first pole piece; 12, center hole; 13, second pole piece; 20, pole piece body; 21, winding start; 22, winding end; 23, coating area; 24, blank foil area; 25, active material layer; 30, tab area; 31, tab cluster; 301, first tab area to be bent; 302, second tab area to be bent; 32, first tab group; 33, spacing groove; 34, second tab group; 35, bending gap; 36, buffer zone; 37, bending line; 38, avoidance gap; 39, tab-free area; 40, tab portion; 50. Current collecting plate; 51. Pole ear connection part; 511. Sub-pole ear connection part; 52. Avoidance opening; 521. Middle opening area; 522. Branch opening area; 53. Flexible buffer part; 531. Middle spring piece; 532. Elastic connecting piece; 60. Cutting tool. DETAILED DESCRIPTION

[0049] The following describes in detail embodiments of the present application. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application and are not to be construed as limiting the present application.

[0050] The battery cell 100 according to an embodiment of the present application is described below with reference to the accompanying drawings.

[0051] 1 to 9 , according to the battery cell 100 of the embodiment of the first aspect of the present application, the battery cell 100 is used for a cylindrical battery, and the battery cell 100 includes: a battery cell wound body 10, including a first pole piece 11, a second pole piece 13 and a separator arranged in a wound manner, the first pole piece 11 and the second pole piece 13 having opposite polarities, and the separator being arranged between the first pole piece 11 and the second pole piece 13. The first pole piece 11 and / or the second pole piece 13 include a pole piece body 20 and an active material layer 25. For example, the first pole piece 11 includes a pole piece body 20 and an active material layer 25; or the second pole piece 13 includes a pole piece body 20 and an active material layer 25; or the first pole piece 11 includes a pole piece body 20 and an active material layer 25, and the second pole piece 13 includes a pole piece body 20 and an active material layer 25.

[0052] During the preparation process of the cylindrical battery cell 100, the first electrode sheet 11, the diaphragm and the second electrode sheet 13 are stacked, one of the first electrode sheet 11 and the second electrode sheet is a positive electrode and the other is a negative electrode, and a diaphragm is sandwiched between the first electrode sheet 11 and the second electrode sheet 13. The two ends of the first electrode sheet 11 and the second electrode sheet 13 along the unfolding direction (refer to the e1 direction in Figure 1) are the winding start end 21 and the winding end 22 respectively. The winding needle is set at the winding start end 21 of the first electrode sheet 11 and the second electrode sheet 13, and winding starts from the winding start end 21 until it is wound to the winding end 22 of the first electrode sheet 11 and the second electrode sheet 13. After the winding is completed, a cylindrical battery cell winding body 10 is formed, and a winding needle hole is formed in the center of the battery cell 100. The winding needle is located at the winding needle hole. After the winding needle is pulled out, the formed winding needle hole constitutes the center hole 12 of the battery cell 100. The gas generated in the chemical reaction of the cylindrical battery can be discharged through the central hole 12 of the battery cell 100 . In addition, during the liquid injection operation of the cylindrical battery, the electrolyte can enter the interior of the battery cell 100 through the central hole 12 of the battery cell 100 .

[0053] The pole piece body 20 includes a coating area 23 and a hollow foil area 24 connected to one side of the coating area 23 along the axial direction of winding, and the active material layer 25 covers the coating area 23. The coating area 23 and the hollow foil area 24 are arranged along the width direction of the pole piece body 20 (refer to the e2 direction of Figure 1). The width direction of the pole piece body 20 is parallel to the axial direction of winding. The central axis direction of the battery cell winding body 10 is consistent with the axial direction of winding. The width direction of the pole piece body 20 is perpendicular to the unfolding direction of the pole piece body 20. As part of the pole piece body 20, the hollow foil area 24 does not need to be separately made into a pole lug area, and there is no need to connect the separately made pole lug area with the coating area 23 of the pole piece body 20. For example, there is no need to separately make a pole lug area and then connect the pole lug area to the coating area 23 of the pole piece body 20 by welding. This setting can reduce the difficulty of processing and manufacturing the pole piece body 20, simplify the production process, and improve production efficiency to a certain extent.

[0054] At least a portion of the empty foil area 24 is suitable for being bent to form a tab portion 40. For example, a portion of the empty foil area 24 constitutes the tab region 30, or the entire empty foil area 24 constitutes the tab region 30. The tab region is suitable for being bent to form the tab portion 40. The tab portion 40 includes a plurality of first tab groups 32 spaced apart along a winding circumferential direction, wherein the winding circumferential direction is perpendicular to the winding axial direction.

[0055] It should be noted that the “plurality” in this application refers to two or more.

[0056] For example, referring to FIG. 3 and FIG. 7 , the tab portion 40 includes eight first tab groups 32 spaced apart along the winding circumferential direction.

[0057] During the process of forming the pole lug portion 40, after the first pole piece 11, the diaphragm, and the second pole piece 13 are wound, the pole lug regions 30 located on the same side of the winding axial direction (refer to the e3 direction in FIG2 ) form a pole lug cluster 31. The pole lug cluster 31 can be a positive pole lug cluster or a negative pole lug cluster. The pole lug cluster 31 is divided into a plurality of regions spaced apart along the winding circumferential direction, and then the plurality of regions of the pole lug cluster 31 are bent and smoothed to form a plurality of first pole lug groups 32. Before the pole lug cluster 31 is bent and smoothed to form the pole lug portion 40, since the pole lug cluster 31 is divided into a plurality of regions spaced apart along the winding circumferential direction, in the process of bending and smoothing the plurality of regions of the pole lug cluster 31 to form the plurality of first pole lug groups 32, since adjacent first pole lug groups 32 are spaced apart, collision and extrusion between the adjacent first pole lug groups 32 to generate metal chips can be avoided, thereby reducing the risk of short circuit caused by the bending and smoothing of the pole lug portion 40.

[0058] During the bending and smoothing process, the first tab group 32 is gradually flattened from the bent state under the action of pressure. By arranging multiple first tab groups 32 at intervals so that there is a certain distance between adjacent first tab groups 32, it is possible to avoid interference between the first tab groups 32 and adjacent first tab groups 32 during the bending and smoothing process, thereby ensuring the flatness of the surface of the first tab group 32.

[0059] According to the battery cell 100 of the embodiment of the present application, by setting the pole ear portion 40 as a plurality of first pole ear groups 32 spaced apart along the winding circumferential direction, in the process of bending and smoothing at least a portion of the empty foil area 24 to form the pole ear portion 40, since two adjacent first pole ear groups 32 are spaced apart, collision and squeezing between the two adjacent first pole ear groups 32 to generate metal chips can be avoided, thereby reducing the risk of short circuit caused by the bending and smoothing of the pole ear portion 40.

[0060] According to some embodiments of the present application, referring to Figures 5 and 9 , the outer contour of the orthographic projection of the first tab group 32 in the winding axial direction is fan-shaped. The fan-shaped outer contour of the orthographic projection of the first tab group 32 in the winding axial direction provides the first tab group 32 with a larger area, which enables the tab portion 40 to have a larger current flow capacity, thereby improving the charge and discharge performance of the cylindrical battery.

[0061] In addition, the larger area of ​​the first tab group 32 can facilitate the processing and assembly of the tab region 30. For example, when welding the tab region 30, the larger area of ​​the first tab group 32 can provide a larger welding area and operating space, facilitating the welding operation.

[0062] Referring to Figures 3 and 6-7 , according to some embodiments of the present application, the number of first tab groups 32 is 5 to 16. For example, the number of first tab groups 32 can be 5, 8, 11, 14, 16, etc. If the number of first tab groups 32 is less than 5, the number of first tab groups 32 is too small, and the bending and smoothing area of ​​each first tab group 32 is large. This large processing area is not conducive to ensuring the surface flatness of each first tab group 32. If the number of first tab groups 32 is greater than 16, the number of first tab groups 32 that need to be processed is too large, which increases the difficulty of processing. The large processing area also affects the current carrying capacity of the tab portion 40 to a certain extent. By setting the number of first tab groups 32 to 5 to 16, the surfaces of multiple first tab groups 32 can be relatively flat, facilitating the subsequent processing and assembly of the tab portion 40. At the same time, the current carrying capacity of the tab portion 40 can be guaranteed, thereby ensuring the charge and discharge performance of the cylindrical battery.

[0063] Optionally, the plurality of first tab groups 32 may be evenly distributed at equal angles to facilitate the processing and manufacturing of the first tab groups 32 .

[0064] For example, referring to FIG. 3 and FIG. 7 , the number of the first electrode tab groups 32 is eight, and the eight first electrode tab groups 32 are evenly distributed at equal angles.

[0065] 2 and 4 , according to some embodiments of the present application, the two opposite sides of the first tab group 32 in the winding circumferential direction are the third side and the fourth side, respectively. The extension line of the third side and the extension line of the fourth side are set at an angle. The angle between the extension line of the third side and the extension line of the fourth side is α, and the angle α between the extension line of the third side and the extension line of the fourth side is in the range of 22.5° to 80°.

[0066] The angle α ranges from 22.5° to 80°. For example, the angle α can be 22.5°, 30°, 40°, 50°, 60°, 70°, 80°, etc. If the angle α is less than 22.5°, the angle α is smaller, the area of ​​the first tab assembly 32 is smaller, and a larger number of first tab assemblies 32 need to be processed, which increases the difficulty of processing. The larger processing area will affect the current flow capacity of the tab portion 40 to a certain extent. If the angle α is greater than 72°, the angle α is larger, the bending and smoothing area of ​​the first tab assembly 32 is larger, and the larger processing area is not conducive to ensuring the surface flatness of each first tab assembly 32. By setting the angle α between 22.5° and 72°, the surfaces of multiple first tab assemblies 32 can be relatively flat, facilitating the subsequent processing and assembly of the tab portion 40. At the same time, the current flow capacity of the tab portion 40 can be guaranteed, thereby ensuring the charge and discharge performance of the cylindrical battery.

[0067] Optionally, if the plurality of first tab groups 32 are uniformly distributed at equal angles, the number of the first tab groups 32 determines the angles of the first tab groups 32 .

[0068] 3 and 6 , according to some embodiments of the present application, the spacing between adjacent first tab groups 32 ranges from 0.5 mm to 8 mm. For example, the spacing between adjacent first tab groups 32 can be 0.5 mm, 2 mm, 4 mm, 6 mm, 8 mm, etc. During the bending and flattening process, the first tab groups 32 are gradually flattened from their bent state under pressure, and adjacent first tab groups 32 are prone to collision and compression during the flattening process.

[0069] If the spacing between adjacent first tab groups 32 is less than 0.5 mm, the spacing between adjacent first tab groups 32 is too small, which will cause interference between the two adjacent first tab groups 32 during the bending and smoothing process, thereby affecting the flatness of the surface of the tab portion 40 and hindering subsequent processing and assembly. If the spacing between adjacent first tab groups 32 is greater than 8 mm, the spacing between adjacent first tab groups 32 is too large, resulting in a smaller area of ​​the first tab group 32, thereby affecting the current flow capacity of the tab portion 40. By setting the spacing between the first tab groups 32 to 0.5 mm to 8 mm, the surface flatness of the tab portion 40 can be ensured, thereby facilitating subsequent processing and assembly. At the same time, the current flow capacity of the tab portion 40 can be guaranteed, thereby ensuring the charge and discharge performance of the cylindrical battery.

[0070] 3 and 6 , according to some embodiments of the present application, on the same winding, the circumferential dimension of the first tab group 32 is greater than the circumferential spacing between adjacent first tab groups 32. The circumferential dimension of the first tab group 32 is greater than the circumferential spacing between adjacent first tab groups 32, which enables the area of ​​the first tab group 32 to be greater than the area of ​​the spacing region between adjacent first tab groups 32, thereby enabling the first tab group 32 to have a larger area, and thus enabling the tab portion 40 to have a greater current flow capacity.

[0071] 3 , according to some embodiments of the present application, a spacing groove 33 is formed between adjacent first tab groups 32. During the bending and smoothing process, the first tab groups 32 are gradually flattened from a bent state under pressure, and adjacent first tab groups 32 are prone to collision and extrusion during the flattening process. By providing a spacing groove 33 between two adjacent first tab groups 32, a certain distance is provided between the two adjacent first tab groups 32, which can avoid interference between the two adjacent first tab groups 32 during the bending and smoothing process, thereby ensuring the surface flatness of the tab portion 40, facilitating subsequent processing and assembly, and at the same time, ensuring that the tab portion 40 has a large flow capacity.

[0072] The number of the spacing grooves 33 is equal to the number of the first tab groups 32 .

[0073] For example, referring to FIG. 3 , the number of the first electrode tab groups 32 is eight, and the number of the spacing grooves 33 between two adjacent first electrode tab groups 32 is eight.

[0074] Optionally, the spacing groove 33 can be mechanically cut by a cutting tool 60, or formed by laser die cutting, or processed by an ultrasonic vibrator.

[0075] According to some embodiments of the present application, the battery cell winding body 10 includes a first pole piece 11, a second pole piece 13 and an isolation film that are wound together. The first pole piece 11 and / or the second pole piece 13 include a pole piece body 20. The pole piece body 20 includes a coating area 23 and an empty foil area 24 connected to one side of the coating area 23. The empty foil area 24 includes a pole lug area 30. The pole lug area 30 is bent to form a pole lug portion 40. The pole lug portion 40 includes a plurality of first pole lug groups 32 spaced apart along the winding circumference, and a spacing groove 33 is formed between two adjacent first pole lug groups 32.

[0076] In this embodiment, the manufacturing process of the tab portion 40 is as follows:

[0077] First, after winding the stacked first and second pole pieces 11, 13, and separators, multiple spacing grooves 33 (see Figure 3) are machined into the tab cluster 31. The spacing grooves 33 are laser-cut to form a plurality of uniformly distributed and shaped spacing grooves 33 along the circumference of the winding process.

[0078] The area between the two spacing grooves 33 is the first tab area to be bent.

[0079] Then, a bending tool is used to bend and smooth the first tab area to be bent (see Figure 2). The number of bending tools is equal to and corresponds to the first tab groups 32. Multiple bending tools simultaneously bend and smooth the corresponding first tab areas 301 to be bent toward the direction close to the axis of the winding shaft (i.e., the direction of the central hole 12 of the battery cell winding body 10). After the multiple first tab areas 301 are bent and smoothed, multiple first tab groups 32 are formed.

[0080] In the process of bending and smoothing the first tab group 32 by the bending tool, the first tab group 32 is gradually flattened from the bent state under the pressure of the bending tool. There is a spacing groove 33 between the two adjacent first tab groups 32, so that there is a certain distance between the two adjacent first tab groups 32, which can avoid the first tab group 32 from interfering with the adjacent first tab group 32 during the flattening process.

[0081] By cutting the spacing grooves 33 and bending and smoothing the first tab group 32 with a bending tool, the surface of the tab portion 40 can be made relatively uniform and smooth, and the problem of collision and squeezing of the tab area 30 caused by irregular smoothing, thereby generating metal chips, can be avoided. The process stability is better, and the current flow capacity of the tab portion 40 is greater.

[0082] Referring to Figure 3 , according to some embodiments of the present application, along the winding axis, the two opposing sides of the spacing groove 33 in the circumferential direction of the battery cell jellyroll 10 are respectively a first side and a second side, with the extension of the first side being parallel to or at an angle to the extension of the second side. This simplifies the shape of the spacing groove 33 and facilitates its fabrication.

[0083] Furthermore, on the same winding coil, the circumferential dimension of the first tab group 32 is larger than the circumferential dimension of the spacing groove 33, so as to ensure that the area of ​​the first tab group 32 is larger than the area of ​​the spacing groove 33 between adjacent first tab groups 32, thereby enabling the first tab group 32 to have a larger area, thereby ensuring the flow capacity of the tab portion 40 and improving the charge and discharge performance of the cylindrical battery.

[0084] 6 , according to some embodiments of the present application, the tab portion 40 includes a plurality of second tab groups 34 spaced apart along the winding circumferential direction. The second tab groups 34 are arranged alternately with the first tab groups 32 in the winding circumferential direction, and bending gaps 35 are formed between adjacent second tab groups 34 and first tab groups 32. During the bending and smoothing process, the second tab groups 34 are gradually flattened from a bent state under the action of pressure. Adjacent first tab groups 32 and second tab groups 34 are prone to collision and compression during the flattening process. By providing bending gaps 35 between adjacent first tab groups 32 and second tab groups 34, interference between adjacent first tab groups 32 and second tab groups 34 during the bending and smoothing process can be avoided, thereby ensuring the surface flatness of the first tab groups 32 and second tab groups 34, and facilitating subsequent processing and manufacturing.

[0085] The number of the bending gaps 35 is twice that of the second tab group 34 .

[0086] Optionally, the bending gap 35 can be mechanically cut by a cutting tool 60, or formed by laser die cutting, or processed by an ultrasonic vibrator.

[0087] For example, referring to FIG5-FIG6 , the number of the second tab groups 34 spaced apart along the circumference of the battery cell wound body 10 is 8, and the number of the bending slits 35 mechanically cut and formed by the cutting tool 60 is 16.

[0088] 5-6 , according to some embodiments of the present application, on the same winding coil, the circumferential dimension of the second tab group 34 is larger than the circumferential dimension of the bending gap 35 , so that the area of ​​the second tab group 34 is larger than the area of ​​the bending gap 35 , thereby enabling the bending gap 35 to have a smaller area, thereby ensuring that the second tab group 34 has a larger area, thereby ensuring the current flow capacity of the tab portion 40 .

[0089] Referring to Figures 5 and 6 , according to some embodiments of the present application, on the same winding coil, the second tab assembly 34 has two opposing sides in the cell winding circumferential direction, namely the fifth side and the sixth side, with the extension of the fifth side being parallel to or at an angle to the extension of the sixth side. This simplifies the shape of the second tab assembly 34 and facilitates its processing and manufacturing.

[0090] Furthermore, on the same winding coil, the circumferential dimension of the first tab group 32 is larger than the circumferential dimension of the second tab group 34 to ensure that the area of ​​the first tab group 32 is larger than the area of ​​the second tab group 34. This enables the first tab group 32 to have a larger area, thereby improving the current flow capacity of the tab portion 40 and improving the charge and discharge performance of the cylindrical battery.

[0091] 4 , according to some embodiments of the present application, at least one end of the first tab group 32 along the winding circumferential direction is disposed on a side of the adjacent second tab group 34 away from the coating area 23. That is, one end of the first tab group 32 along the winding circumferential direction may be disposed on a side of the adjacent second tab group 34 away from the coating area 23, or both ends of the first tab group 32 along the winding circumferential direction may be disposed on a side of the two adjacent second tab groups 34 away from the coating area 23.

[0092] By arranging at least one end of the first pole tab group 32 along the winding circumferential direction on the side of the adjacent second pole tab group 34 away from the coating area 23, the structure of the pole tab portion 40 is more reasonable, which can avoid the first pole tab group 32 and the second pole tab group 34 from being squeezed and collided, thereby ensuring the surface flatness of the first pole tab group 32 and the second pole tab group 34, and facilitating the processing and assembly of the pole tab portion 40; at the same time, by arranging at least one end of the first pole tab group 32 along the winding circumferential direction on the side of the adjacent second pole tab group 34 away from the coating area 23, the area of ​​the bending gap 35 can be greatly reduced, so that the first pole tab group 32 and the second pole tab group 34 have a larger area, thereby making the pole tab portion 40 have a larger current capacity.

[0093] In addition, by arranging at least one end of the first tab group 32 in the winding circumferential direction on the side of the adjacent second tab group 34 away from the coating area 23, a height difference is created between the first tab group 32 and the second tab group 34, which facilitates the subsequent processing and manufacturing of the cylindrical battery.

[0094] For example, when a cylindrical battery is injected with electrolyte, the electrolyte can enter the battery cell 100 through the gap between the first electrode piece 11 and the second electrode piece 13 and infiltrate the coating area 23 of the electrode piece body 20. There is a height difference between the first electrode tab group 32 and the second electrode tab group 34, so that there is a gap between the collecting plate 50 connected to the first electrode tab group 32 and the second electrode tab group 34. The electrolyte can enter the gap between the first electrode piece 11 and the second electrode piece 13 through the gap between the collecting plate 50 and the second electrode tab group 34, and then infiltrate the coating area 23 of the electrode piece body 20. This can avoid the situation where the collecting plate 50 and the electrode tab portion 40 are too tightly fitted, making it difficult for the electrolyte to enter the battery cell 100 from the gap between the first electrode piece 11 and the second electrode piece 13, thereby facilitating the entry of the electrolyte after injection, improving the infiltration effect of the battery cell 100, shortening the injection time of the battery cell 100, and improving the injection efficiency.

[0095] According to some embodiments of the present application, the battery cell winding body 10 includes a first pole piece 11, a second pole piece 13 and an isolation film that are wound together. The first pole piece 11 and / or the second pole piece 13 include a pole piece body 20. The pole piece body 20 includes a coating area 23 and an empty foil area 24 connected to one side of the coating area 23. The empty foil area 24 includes a pole lug area 30. The pole lug area 30 is bent to form a pole lug portion 40. The pole lug portion 40 includes a first pole lug group 32 and a second pole lug group 34 that are spaced apart along the winding circumference. A bending gap 35 is formed between adjacent first pole lug groups 32 and second pole lug groups 34.

[0096] The bending and smoothing operation of the tab cluster 31 is as follows:

[0097] First, after the first pole piece 11, the second pole piece 13, and the isolation film are wound, a plurality of bending slits 35 are machined on the tab cluster 31 (see FIG6 ). The bending slits 35 are cut and formed using a cutting tool 60. The cutting tool 60 cuts the tab cluster 31 along the radial direction of the tab cluster 31, forming two bending slits 35 spaced apart along the winding circumference (see FIG5 ). The tab cluster 31 is then cut multiple times at equal angles to form a plurality of bending slits 35.

[0098] After the bending slits 35 are cut, first tab regions 301 to be bent and second tab regions 302 to be bent are formed, which are alternately arranged along the winding circumferential direction.

[0099] Next, a second bending tool is used to bend and smooth the second tab area 302 to be bent (see FIG7 ) to form a second tab group 34. The number of second bending tools is the same as the number of second tab groups 34 and corresponds to each second tab group 34. Multiple second bending tools simultaneously bend and smooth the corresponding multiple second tab areas 302 to be bent in a direction close to the axis of the reel. After bending and smoothing, the multiple second tab areas 302 to be bent form multiple second tab groups 34.

[0100] Among them, when the second bending tool is bending and smoothing the second pole tab group 34, the second pole tab group 34 is gradually flattened from a bent state under the pressure of the second bending tool, and a bending gap 35 is provided between the adjacent first pole tab group 32 and the second pole tab group 34, so that there is a certain distance between the first pole tab group 32 and the second pole tab group 34, which can avoid the second pole tab group 34 from interfering with the adjacent first pole tab group 32 during the flattening process.

[0101] Finally, a first bending tool is used to bend and smooth the first tab area 301 to be bent (see FIG4 ) to form a first tab group 32. The number of first bending tools is the same as the number of first tab groups 32 and corresponds to the first tab groups 32 one by one. Multiple first bending tools simultaneously bend and smooth the corresponding multiple first tab areas 301 to be bent in a direction close to the winding axis. After bending and smoothing, multiple first tab areas 301 to be bent form multiple first tab groups 32.

[0102] The first tab area 301 to be bent is bent and smoothed to form a first tab group 32 , and the second tab area 302 to be bent is bent and smoothed to form a second tab group 34 . The number of the first tab group 32 and the second tab group 34 are the same and are both half the number of the bending gaps 35 (see FIG. 6 ).

[0103] Among them, during the process of the first bending tool bending and smoothing the first pole tab group 32, the first pole tab group 32 is gradually flattened from the bent state under the pressure of the first bending tool, and the second pole tab group 34 has been bent and smoothed, so that the first pole tab group 32 will not collide or be squeezed with the second pole tab group 34 in the process of being gradually flattened, and after the first pole tab group 32 is bent and smoothed, the two ends of the first pole tab group 32 along the circumferential direction of the winding body are respectively pressed on the side of the two adjacent second pole tab groups 34 away from the coating area 23.

[0104] The processing method of first bending and smoothing the second tab group 34 and then bending and smoothing the first tab group 32 can make the surface of the tab portion 40 more uniform and smooth, and can avoid the problem of collision and squeezing of the tab area 30 caused by irregular smoothing, thereby generating metal chips. The process stability is better, and the current flow capacity of the tab portion 40 is greater.

[0105] Optionally, the second tab area 302 to be bent can be directly formed by a single bending and smoothing during the process of being bent and smoothed by the second bending tool to form the second tab group 34, or it can be formed after multiple bending and smoothing; the first tab area 301 to be bent can be directly formed by a single bending and smoothing during the process of being bent and smoothed by the first bending tool to form the first tab group 32, or it can be formed after multiple bending and smoothing.

[0106] 1 , according to some embodiments of the present application, the hollow foil region 24 includes a buffer zone 36 and a tab region 30. The buffer zone 36 is connected between the tab region 30 and the coating region 23. A bend line 37 is defined between the buffer zone 36 and the tab region 30. The tab region 30 is adapted to be bent at the bend line 37 to form a tab portion 40. By providing the buffer zone 36 between the coating region 23 and the tab region 30, the buffer zone 36 can protect the coating region 23, reducing or preventing damage to the coating region 23 during processing of the tab region 30. Furthermore, by providing the buffer zone 36, the overcurrent capacity of the cylindrical battery can be largely guaranteed, thereby ensuring the charge and discharge performance of the cylindrical battery.

[0107] For example, by providing a buffer zone 36, a certain distance is created between the coating area 23 and the tab area 30. During welding of the tab area 30, the high temperature generated during the welding process can be dissipated through the buffer zone 36, thereby lowering the temperature of the coating area 23 and reducing or preventing damage to the coating area 23 and the separator of the pole piece body 20 due to high temperatures. Furthermore, the buffer zone 36 can ensure the flatness of the welding surface during the welding of the tab portion 40 through slight deformation, thereby ensuring the welding quality of the tab portion 40, thereby ensuring the current flow capacity of the tab portion 40 and the charge and discharge performance of the cylindrical battery.

[0108] 1 , according to some embodiments of the present application, the height of the empty foil area 24 in the axial direction of the winding is in the range of 3 mm to 10 mm. For example, in the axial direction of the winding, the height of the empty foil area 24 can be 3 mm, 5 mm, 7 mm, 9 mm, 10 mm, etc. In the axial direction of the winding, if the size of the empty foil area 24 is less than 3 mm, the size of the empty foil area 24 in the axial direction of the winding is small, which will result in the area of ​​the tab area 30 being too small, thereby resulting in a low current flow capacity of the tab portion 40; in the axial direction of the winding, if the size of the empty foil area 24 is greater than 10 mm, the size of the empty foil area 24 in the axial direction of the winding is large, which will result in the empty foil area 24 occupying a large space, thereby resulting in a low energy density of the cylindrical battery.

[0109] By setting the size of the empty foil area 24 in the axial direction of winding to 3mm~10mm, the size of the empty foil area 24 in the width direction of the pole piece body 20 is more appropriate, thereby ensuring the flow capacity of the pole ear portion 40, and then ensuring the charge and discharge performance of the cylindrical battery. In addition, by setting the size of the empty foil area 24 in the axial direction of winding to 3mm~10mm, it can be ensured that the cylindrical battery has a higher energy density.

[0110] 1 to 7 , according to some embodiments of the present application, a portion of the hollow foil area 24 close to the winding axis is formed with an avoidance notch 38, and the avoidance notch 38 constitutes a tab-free area 39. At least a portion of the hollow foil area 24 (i.e., the tab area 30 described above) is bent toward the direction adjacent to the winding axis to form a tab portion 40. During the process of winding to form the battery cell wound body 10, the winding needle is located at the center hole 12. By providing the avoidance notch 38 in the portion of the hollow foil area 24 close to the winding axis, the tab-free area 39 is formed by the avoidance notch 38. This can prevent the tab area 30 from interfering with the center hole 12 after bending toward the center axis of the battery cell wound body 10, thereby affecting the wetting and exhaust effects of the center hole 12.

[0111] Optionally, the avoidance gap 38 can be formed by laser die cutting.

[0112] 8 , according to some embodiments of the present application, the battery cell 100 includes a current collecting plate 50. The current collecting plate 50 is disposed on a side of the tab portion 40 away from the coating area 23 and is electrically connected to the first tab group 32. The surface of the first tab group 32 is relatively flat, which facilitates electrical connection with the current collecting plate 50 when multiple first tab groups 32 have a large area. Furthermore, the electrical connection between the current collecting plate 50 and the larger first tab group 321 can improve the current carrying capacity of the tab portion 40, thereby enhancing the charge and discharge performance of the cylindrical battery.

[0113] Optionally, the collecting plate 50 and the first tab group 32 can be connected by welding. The first tab group 32 has a relatively flat surface and a large area, which can provide sufficient operating space to facilitate welding operations. The large welding area can ensure welding quality.

[0114] 8 , according to some embodiments of the present application, the current collecting plate 50 includes a tab connecting portion 51 and a flexible buffer portion 53 . The tab connecting portion 51 is electrically connected to the first tab group 32 , and the flexible buffer portion 53 is deformable in the winding axial direction.

[0115] When the battery cell 100 undergoes axial displacement, the first pole tab group 32 electrically connected to the collecting plate 50 is prone to stress concentration. By providing a flexible buffer portion 53, and the flexible buffer portion 53 can be deformed in the axial direction of winding, when the battery cell 100 undergoes axial displacement, the flexible buffer portion 53 can reduce the stress concentration of the first pole tab group 32 through deformation, thereby playing a buffering role and avoiding the situation where the first pole tab group 32 is fractured due to stress caused by the axial displacement of the battery cell 100.

[0116] 8-9 , according to some embodiments of the present application, a bypass opening 52 is formed on the collecting plate 50 , and in the axial direction of winding, at least a portion of the flexible buffer portion 53 is opposite to the bypass opening 52 , that is, a portion of the flexible buffer portion 53 may be opposite to the bypass opening 52 , or the entire flexible buffer portion 53 may be opposite to the bypass opening 52 .

[0117] By providing the avoidance opening 52 on the current collecting disc 50 and with at least a portion of the flexible buffer portion 53 facing the avoidance opening 52, the provision of the avoidance opening 52 can provide deformation space for the flexible buffer portion 53 to deform in the winding axial direction, and can prevent the flexible buffer portion 53 of the current collecting disc 50 from interfering with the center hole 12 and affecting the exhaust and infiltration effects of the center hole 12. In addition, by providing the avoidance opening 52, the gas generated during the chemical reaction of the cylindrical battery can also be discharged through the avoidance opening 52, thereby improving the exhaust effect; at the same time, during the process of injecting liquid into the cylindrical battery, the electrolyte can enter the gap between the center hole 12 and the electrode 11 at the avoidance opening 52, and then enter the interior of the battery cell 100, thereby facilitating the entry of the electrolyte after injection, improving the infiltration effect of the battery cell 100, shortening the injection time of the battery cell 100, and improving the injection efficiency.

[0118] 8-9 , according to some embodiments of the present application, the flexible buffer portion 53 includes an intermediate spring piece 531 and a plurality of elastic connecting pieces 532 arranged at intervals along the circumference of the current collecting disk 50. The intermediate spring piece 531 is located in the middle of the current collecting disk 50. One end of the elastic connecting piece 532 is connected to the intermediate spring piece 531. The other end of the elastic connecting piece 532 extends in a direction away from the center of the current collecting disk 50 and is connected to the pole ear connecting portion 51. In the axial direction of winding, the elastic connecting piece 532 and the intermediate spring piece 531 are opposite to the avoidance opening 52.

[0119] One end of the elastic connecting piece 532 is connected to the intermediate elastic piece 531, and the other end of the elastic connecting piece 532 extends in a direction away from the center of the current collecting plate 50 and is connected to the tab connection portion 51. For example, the intermediate elastic piece 531 can be connected to the pole of a cylindrical battery. During the discharge process of the cylindrical battery, the current is transmitted through the first tab group 32 to the tab connection portion 51 of the current collecting plate 50 to which it is electrically connected. Then, the current is transmitted from the tab connection portion 51 to the end of the elastic connecting piece 532 of the current collecting plate 50 connected to the tab connection portion 51, and then to the other end of the elastic connecting piece 532 and to the intermediate elastic piece 531 connected thereto. Finally, the current is transmitted through the intermediate elastic piece 531 to the pole of the cylindrical battery, completing the discharge process of the cylindrical battery.

[0120] During the charging process of the cylindrical battery, the external current is transmitted through the pole of the cylindrical battery to the middle spring piece 531 of the flexible buffer part 53 and one end of the elastic connecting piece 532 connected to the middle spring piece 531, and then transmitted to the other end of the elastic connecting piece 532 connected to the pole ear connecting part 51, and then transmitted to the pole ear connecting part 51 of the collecting plate 50, and finally transmitted through the pole ear connecting part 51 to the first pole ear part 41 electrically connected to it, completing the charging process of the cylindrical battery.

[0121] In the winding axial direction, the elastic connecting piece 532 and the middle spring piece 531 are opposite to the avoidance opening 52 . The avoidance opening 52 can provide space for the deformation of the elastic connecting piece 532 and the middle spring piece 531 , and can also ensure the exhaust and infiltration effects of the avoidance opening 52 .

[0122] For example, referring to FIG. 6 , the flexible buffer portion 53 includes a middle elastic piece 531 and four elastic connecting pieces 532 spaced apart along the circumference of the collecting plate 50 . In the winding axial direction, the four elastic connecting pieces 532 and the middle elastic piece 531 are opposite to the avoidance opening 52 .

[0123] 8-9 , according to some embodiments of the present application, the width of the elastic connecting piece 532 in the circumferential direction of the collecting plate 50 ranges from 4 mm to 10 mm. For example, the width of the elastic connecting piece 532 in the circumferential direction of the current collecting disc 50 can be 4 mm, 6 mm, 8 mm, 10 mm, etc. If the width of the elastic connecting piece 532 in the circumferential direction of the current collecting disc 50 is less than 4 mm, the width of the elastic connecting piece 532 in the circumferential direction of the current collecting disc 50 will be smaller, so that the area of ​​the elastic connecting piece 532 is smaller, resulting in a smaller flow capacity of the elastic connecting piece 532, thereby affecting the charge and discharge performance of the cylindrical battery; if the width of the elastic connecting piece 532 in the circumferential direction of the current collecting disc 50 is greater than 10 mm, the width of the elastic connecting piece 532 in the circumferential direction of the current collecting disc 50 will be larger, resulting in a smaller area of ​​the pole ear connection portion 51 of the current collecting disc 50, so that the connection area between the current collecting disc 50 and the first pole ear group 32 is smaller, and further resulting in a lower flow capacity of the pole ear portion 40.

[0124] By setting the width of the elastic connecting piece 532 in the circumferential direction of the current collecting plate 50 to 4 mm to 10 mm, both the tab portion 40 and the elastic connecting piece 532 can have a large current capacity, thereby ensuring the charge and discharge performance of the cylindrical battery.

[0125] 8-9 , according to some embodiments of the present application, the avoidance opening 52 includes a middle opening area 521 and a plurality of branch opening areas 522 connected to the middle opening area 521. The plurality of branch opening areas 522 are located on the outer periphery of the middle opening area 521 and are spaced apart along the circumference of the collecting plate 50. By providing the middle opening area 521 and the plurality of spaced-apart branch opening areas 522 connected to the middle opening area 521, the middle opening area 521 can provide space for the deformation of the middle elastic piece 531, and the branch opening areas 522 can provide space for the deformation of the corresponding elastic connecting piece 532. Furthermore, the plurality of spaced-apart branch opening areas 522 connected to the middle opening area 521 can ensure more uniform exhaust and infiltration effects of the avoidance opening 52.

[0126] In the winding axial direction, the middle spring piece 531 is opposite the middle opening area 521, and the elastic connecting piece 532 is opposite the branch opening area 522. The middle spring piece 531 and the elastic connecting piece 532 are opposite the middle opening area 521 and the branch opening area 522, respectively. This ensures that the structures of the avoidance opening 52 and the flexible buffer portion 53 are more compatible, making the structure of the avoidance opening 52 more reasonable and reducing the space occupied by the avoidance opening 52 to a certain extent. This allows the tab connection portion 51 of the current collecting plate 50 to have a larger area for electrical connection with the first tab group 32, thereby ensuring that the tab portion 40 has a greater current flow capacity.

[0127] The tab connection portion 51 includes multiple sub-tab connection portions 511 spaced apart along the circumference of the current collecting disk 50, with branch openings 522 located between adjacent sub-tab connection portions 511. By providing multiple sub-tab connection portions 511 spaced apart along the circumference of the current collecting disk 50, each of the sub-tab connection portions 511 is electrically connected to the first tab group 32. This allows for a more regionalized and rational distribution of the sub-tab connection portions 511, facilitates connection between the tab connection portion 51 and the current collecting disk 50, and ensures a more uniform and reasonable connection between the tab connection portion 51 and the first tab group 32, thereby ensuring a more effective connection between the tab connection portion 51 and the first tab group 32. The number of sub-tab connection portions 511 is equal to the number of branch openings 522.

[0128] For example, referring to Figure 8, the avoidance passage 52 includes a middle passage area 521 and four branch passage areas 522 that are connected to the middle passage area 521. The four branch passage areas 522 are located on the outer peripheral side of the middle passage area 521 and are arranged at circumferential intervals along the collecting disk 50. The pole ear connection portion 51 includes four sub-pole ear connection portions 511 arranged at circumferential intervals along the collecting disk 50.

[0129] 8-9 , according to some embodiments of the present application, the distance between the radial outer edge of the branch opening area 522 and the outer edge of the current collecting plate 50 ranges from 3 mm to 12 mm. For example, the distance between the radial outer edge of the branch opening area 522 and the outer edge of the current collecting plate 50 can be 3 mm, 6 mm, 9 mm, 12 mm, etc. If the distance between the radial outer edge of the branch opening area 522 and the outer edge of the collecting disk 50 is less than 3 mm, the distance between the radial outer edge of the branch opening area 522 and the outer edge of the collecting disk 50 will be smaller, resulting in a larger space occupancy of the branch opening area 522 and a smaller area of ​​the pole ear connection portion 51, which in turn leads to a smaller flow capacity of the pole ear portion 40; if the distance between the radial outer edge of the branch opening area 522 and the outer edge of the collecting disk 50 is greater than 12 mm, the distance between the radial outer edge of the branch opening area 522 and the outer edge of the collecting disk 50 will be larger, resulting in a smaller area of ​​the avoidance opening 52, thereby affecting the buffering effect of the flexible buffer portion 53, and also affecting the exhaust and infiltration effects of the avoidance opening 52.

[0130] By setting the distance between the radial outer edge of the branch outlet area 522 and the outer edge of the collecting plate 50 to 3mm to 12mm, the tab area 30 can be guaranteed to have a larger flow capacity, while the buffering effect, exhaust and wetting effect of the flexible buffer part 53 can be guaranteed.

[0131] 8-9 , according to some embodiments of the present application, in the axial direction of winding, at least a portion of the branch opening area 522 is opposite to the area between the two adjacent first tab groups 32 , that is, a portion of the branch opening area 522 may be opposite to the area between the two adjacent first tab groups 32 , or the entire branch opening may be opposite to the area between the two adjacent first tab groups 32 .

[0132] At least a portion of the branch opening region 522 is opposite to the area between two adjacent first tab groups 32, so that the sub-tab connection portion 511 located between the two adjacent branch opening regions 522 is opposite to the first tab group 32. The first tab group 32 has a larger area, thereby ensuring that the tab portion 40 has a larger flow capacity. At the same time, the tab connection portion 51 and the first tab group 32 have a larger electrical connection area, which can facilitate electrical connection between the sub-tab connection portion 511 and the first tab group 32. For example, when the first tab group 32 is electrically connected to the sub-tab connection portion 511 by welding, the surface of the first tab group 32 is relatively flat and has a larger area, which can facilitate the welding operation and ensure welding quality.

[0133] 8-9 , according to some embodiments of the present application, the flexible buffer portion 53 is formed by stamping a portion of the current collecting tray 50. The flexible buffer portion 53 formed by stamping a portion of the current collecting tray 50 has the advantages of high precision, good quality, a relatively flat surface, and ease of mass production. This can, to a certain extent, simplify the processing steps and improve the efficiency of the processing and forming of the flexible buffer portion 53.

[0134] 1 to 9 , a cylindrical battery according to an embodiment of the second aspect of the present application includes: a battery cell 100 according to the embodiment of the first aspect of the present application. During the preparation of the cylindrical battery, the battery cell 100 is assembled and connected to the battery housing to form a cylindrical battery.

[0135] According to the cylindrical battery of the embodiment of the present application, by providing the above-mentioned battery cell 100, during the process of bending and smoothing to form the pole ear portion 40, collision and extrusion to generate metal chips can be avoided, thereby reducing the risk of short circuit caused during the bending and smoothing of the pole ear portion 40.

[0136] 1-9 , an electrical device according to an embodiment of the third aspect of the present application includes: a cylindrical battery according to the embodiment of the second aspect of the present application.

[0137] Optionally, the electric device may be a vehicle, for example, the electric device may be an electric car.

[0138] According to the electrical equipment of the embodiment of the present application, by providing the above-mentioned cylindrical battery, during the process of manufacturing the cylindrical battery, in the process of bending and smoothing to form the pole ear portion 40, collision and extrusion to generate metal chips can be avoided, thereby reducing the risk of short circuit caused by the bending and smoothing of the pole ear portion.

[0139] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0140] Although the embodiments of the present application have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions, and variations may be made to the embodiments without departing from the principles and intent of the present application, and that the scope of the present application is defined by the claims and their equivalents.

Claims

1. A battery cell (100), wherein: For a cylindrical battery, the battery cell (100) comprises: A battery cell winding body (10) comprises a first pole piece (11), a second pole piece (13) and an isolating film which are wound together, wherein the first pole piece (11) and the second pole piece (13) have opposite polarities, and the isolating film is arranged between the first pole piece (11) and the second pole piece (13), and the first pole piece (11) and / or the second pole piece (13) comprises a pole piece body (20) and an active material layer (25), and the pole piece body (20) comprises a coating area (23) and a hollow foil area (24) connected to one side of the coating area (23) along the winding axial direction, and the active material layer (25) covers the coating area (23), and at least part of the hollow foil area (24) is suitable for bending to form a pole ear portion (40), and the pole ear portion (40) comprises a plurality of first pole ear groups (32) arranged at intervals along the winding circumferential direction.

2. The battery cell (100) according to claim 1, wherein: The number of the first electrode tab groups (32) is 5 to 16.

3. The battery cell (100) according to claim 1 or 2, wherein: The spacing between adjacent first electrode tab groups (32) ranges from 0.5 mm to 8 mm.

4. The battery cell (100) according to any one of claims 1 to 3, wherein: A spacing groove (33) is formed between adjacent first electrode tab groups (32).

5. The battery cell (100) according to any one of claims 1 to 4, wherein: The two opposite sides of the first tab group (32) in the winding circumferential direction are respectively the third side and the fourth side, and the extension line of the third side is arranged at an angle with the extension line of the fourth side, and the angle ranges from 22.5° to 80°.

6. The battery cell (100) according to claim 1, wherein: The pole lug portion (40) comprises a plurality of second pole lug groups (34) arranged at intervals along the winding circumferential direction, the second pole lug groups (34) and the first pole lug groups (32) are alternately arranged in the winding circumferential direction, and a bending gap (35) is formed between adjacent second pole lug groups (34) and first pole lug groups (32).

7. The battery cell (100) according to claim 6, wherein: On the same winding circle, the circumferential dimension of the second pole lug group (34) is greater than the circumferential dimension of the bending gap (35).

8. The battery cell (100) according to claim 6 or 7, wherein: On the same winding circle, two opposite sides of the second electrode tab group (34) in the winding circumferential direction of the battery cell (100) are respectively the fifth side and the sixth side, and the extension line of the fifth side is parallel to or at an angle to the extension line of the sixth side.

9. The battery cell (100) according to any one of claims 6 to 8, wherein: At least one end of the first electrode tab group (32) along the winding circumferential direction is arranged on a side of the adjacent second electrode tab group (34) away from the coating area (23).

10. The battery cell (100) according to any one of claims 1 to 9, wherein: The empty foil area (24) comprises a buffer zone (36) and a pole lug area (30), wherein the buffer zone (36) is connected between the pole lug area (30) and the coating area (23), and a bending line (37) is provided between the buffer zone (36) and the pole lug area (30), and the pole lug area (30) is suitable for being bent at the bending line (37) to form the pole lug portion (40).

11. The battery cell (100) according to any one of claims 1 to 10, wherein: In the axial direction of the winding, the height of the empty foil area (24) ranges from 3 mm to 10 mm.

12. The battery cell (100) according to any one of claims 1 to 11, wherein: A portion of the empty foil area (24) close to the winding axis is formed with an avoidance gap (38), the avoidance gap (38) constitutes a non-electrode lug area (39), and at least a portion of the empty foil area (24) is bent toward the winding axis to form the electrode lug portion (40).

13. The battery cell (100) according to any one of claims 1 to 12, wherein: The battery cell (100) further comprises a current collecting plate (50), wherein the current collecting plate (50) is arranged on a side of the pole lug portion (40) away from the coating area (23), and the current collecting plate (50) is electrically connected to the first pole lug group (32).

14. The battery cell (100) according to claim 13, wherein: The current collecting plate (50) comprises a pole lug connecting portion (51) and a flexible buffer portion (53), wherein the pole lug connecting portion (51) is electrically connected to the first pole lug group (32), and the flexible buffer portion (53) can be deformed in the winding axial direction.

15. The battery cell (100) according to claim 14, wherein: The collecting plate (50) is formed with an escape opening (52), and in the winding axial direction, at least a portion of the flexible buffer portion (53) is opposite to the escape opening (52).

16. The battery cell (100) according to claim 15, wherein: The flexible buffer portion (53) comprises an intermediate spring sheet (531) and a plurality of elastic connecting sheets (532) arranged at intervals along the circumference of the current collecting disk (50); the intermediate spring sheet (531) is located in the middle of the current collecting disk (50); one end of the elastic connecting sheet (532) is connected to the intermediate spring sheet (531); the other end of the elastic connecting sheet (532) extends in a direction away from the center of the current collecting disk (50) and is connected to the pole ear connecting portion (51); in the winding axial direction, the elastic connecting sheet (532) and the intermediate spring sheet (531) are both opposite to the avoidance opening (52).

17. The battery cell (100) according to claim 16, wherein: The width of the elastic connecting piece (532) in the circumferential direction of the current collecting plate (50) ranges from 4 mm to 10 mm.

18. The battery cell (100) according to claim 16, wherein: The avoidance opening (52) comprises a middle opening area (521) and a plurality of branch opening areas (522) which are all connected to the middle opening area (521); the plurality of branch opening areas (522) are located on the outer peripheral side of the middle opening area (521) and are arranged at intervals along the circumference of the collecting plate (50); Wherein, in the winding axial direction, the middle spring sheet (531) is opposite to the middle opening area (521), the elastic connecting sheet (532) is opposite to the branch opening area (522), the pole ear connection portion (51) includes a plurality of sub-pole ear connection portions (511) arranged at intervals along the circumference of the collecting disk (50), and the branch opening area (522) is located between adjacent sub-pole ear connection portions (511).

19. The battery cell (100) according to claim 18, wherein: The distance between the radial outer edge of the branch opening area (522) and the outer edge of the collecting plate (50) ranges from 3 mm to 12 mm.

20. The battery cell (100) according to claim 18 or 19, wherein: In the winding axial direction, at least a portion of the branch opening area (522) is opposite to the area between two adjacent first electrode tab groups (32).

21. A cylindrical battery, wherein: include: The battery cell (100) according to any one of claims 1 to 20.

22. An electrical device, wherein: include: A cylindrical battery according to claim 21.

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