A wound battery cell and battery
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-15
- Publication Date
- 2026-08-11
AI Technical Summary
[0002]随着科技水平的不断提升，手机、平板、电脑、电动汽车等应用产品更新速度不断加快，由此对电芯的要求也越来越高，要求电芯具有更好的性能、更小的体积和更高的能量密度，因此现有的卷芯结构中，极片的压实密度程度持续增大，使得极片的弯折区域承受着较大应力，在经历热压、化成等高压工序时，弯折区域的应力无法得到有效释放，导致断片风险显著提升，最终可能造成电芯容量的损失
[0012]通过于所述集流体的弯折区设置贯穿所述集流体的通孔，且弯折区设置于阴极极片的弯折段内，能降低所述集流体弯折时弯折区处的应力，从而降低所述集流体断片的概率，进而降低电芯容量损失的概率；通过于所述集流体的弯折区处设置贯穿所述集流体的通孔，使卷绕电芯能采用更高的压实密度，从而提升电芯的能量密度。
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Figure CN224625607U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of battery technology, and in particular to a wound battery cell and battery. Background Technology
[0002] With the continuous advancement of technology, the pace of product updates for applications such as mobile phones, tablets, computers, and electric vehicles is accelerating, which in turn places increasingly higher demands on battery cells. These cells require better performance, smaller size, and higher energy density. Consequently, in existing wound core structures, the compaction density of the electrode sheets continues to increase, causing the bending areas of the electrode sheets to bear greater stress. During high-pressure processes such as hot pressing and formation, the stress in the bending areas cannot be effectively released, leading to a significant increase in the risk of cell breakage and potentially resulting in a loss of battery cell capacity. Utility Model Content
[0003] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention proposes a wound battery cell that can effectively reduce the risk of electrode breakage, thereby reducing the probability of battery cell capacity loss.
[0004] This utility model also proposes a battery having the above-mentioned wound battery cell.
[0005] According to a first aspect embodiment of the present invention, a wound battery cell includes:
[0006] Cathode and anode plates;
[0007] Along the width direction of the wound cell, the starting section of the winding of the cathode electrode and the starting section of the winding of the anode electrode extend and are wound in opposite directions;
[0008] Along the thickness direction of the wound cell, there is an overlapping area between the projection of the starting section of the winding of the cathode electrode on the horizontal plane and the projection of the starting section of the winding of the anode electrode on the horizontal plane.
[0009] The cathode electrode includes a current collector and an active material layer. The current collector includes a bending region with multiple through holes. The through holes penetrate the current collector along its thickness direction and are spaced apart along its width direction. The active material layer is coated on the surface of the current collector, and both ends of the through holes are covered with the active material layer.
[0010] The cathode electrode is wound to form multiple bent sections, and among the multiple bent sections, at least the bent section with the largest bending angle has the bending area.
[0011] The wound battery cell according to the embodiments of the present invention has at least the following beneficial effects:
[0012] By providing a through-hole penetrating the current collector in the bending region, and with the bending region located within the bending section of the cathode electrode, the stress at the bending region during bending of the current collector can be reduced, thereby reducing the probability of current collector breakage and consequently reducing the probability of cell capacity loss. Furthermore, by providing a through-hole penetrating the current collector in the bending region, the wound cell can achieve a higher compaction density, thereby increasing the cell's energy density.
[0013] According to some embodiments of the present invention, along the length direction of the current collector, the current collector is provided with a plurality of bending zones at intervals, each bending zone is located within a bending segment, and the number of bending zones is less than or equal to the number of bending segments.
[0014] According to some embodiments of the present invention, the width of the bending area along the length direction of the current collector is 1 mm to 4 mm.
[0015] According to some embodiments of this utility model, the diameter of the through hole is 0.2 mm to 0.5 mm.
[0016] According to some embodiments of the present invention, the cross-sectional shape of the plurality of through holes is the same, and / or the diameter of the plurality of through holes is equal.
[0017] According to some embodiments of the present invention, along the width direction of the current collector, the distance between the edge of the current collector and the nearest through hole is 0.2 mm to 1 mm.
[0018] According to some embodiments of the present invention, the distance between adjacent through holes along the width direction of the current collector is 0.1 mm to 0.5 mm.
[0019] According to some embodiments of the present invention, along the length direction of the current collector, the bending area is provided with multiple rows of through holes, and the through holes in adjacent rows are staggered.
[0020] According to some embodiments of the present invention, along the length direction of the current collector, the bending area is provided with multiple rows of through holes, and the distance between two adjacent rows of through holes is 0.1 mm to 0.5 mm.
[0021] The battery according to a second aspect embodiment of the present invention includes the above-described wound cell. Since the battery of this embodiment uses the above-described wound cell, it also possesses at least all the beneficial effects of a wound cell.
[0022] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description
[0023] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein:
[0024] Figure 1 This is a cross-sectional schematic diagram of a wound battery cell according to the first aspect of this application.
[0025] Figure 2 for Figure 1 A schematic diagram showing the unfolded shape of the central cathode electrode;
[0026] Figure 3 for Figure 2 Enlarged view of point A in the middle;
[0027] Figure 4 For this Figure 2 Cross-sectional view of the middle cathode electrode.
[0028] Icon labels:
[0029] Cathode electrode 100, current collector 110, bending area 111, through hole 112, bending section 113, active material layer 120;
[0030] Anode plate 200. Detailed Implementation
[0031] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.
[0032] In the description of this utility model, it should be understood that the directional descriptions, such as up, down, etc., indicating the directional or positional relationship, are based on the directional or positional relationship shown in the drawings and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.
[0033] In the description of this utility model, "multiple" refers to two or more. The use of "first" and "second" is for distinguishing technical features only and should not be construed as indicating or implying relative importance, or implicitly indicating the number of technical features or their sequential relationship.
[0034] In the description of this utility model, unless otherwise explicitly defined, terms such as "setting," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this utility model in conjunction with the specific content of the technical solution.
[0035] Interlocking wound cells are typically formed by interlocking cathode electrode 100 and anode electrode 200 and then winding them together. Figure 1 As shown in the diagram, along the width direction of the wound cell, the starting sections of the cathode electrode 100 and the anode electrode 200 extend and are wound in opposite directions; along the thickness direction of the wound cell, the projections of the starting sections of the cathode electrode 100 and the anode electrode 200 onto the horizontal plane overlap. During the winding process, the cathode electrode 100 and / or the anode electrode 200 form multiple bends. The stress at these bends is relatively high, especially in high-density wound cells. After undergoing high-pressure processes such as hot pressing and formation, the stress at the bends has nowhere to be released and may cause breakage, leading to fragmentation. This fragmentation results in an internal open circuit in the cathode electrode 100 and / or the anode electrode 200, rendering part of the cell's capacity unusable and consequently reducing the cell's capacity. To reduce the risk of breakage at the bending points of the cathode electrode 100 and / or anode electrode 200, this application proposes a wound battery cell that can effectively reduce the risk of breakage at the bending points of the electrodes; the wound battery cell of this application will be described in detail below with reference to the accompanying drawings.
[0036] Reference Figures 1 to 4 In the first embodiment of this application, the cathode electrode 100 of the wound battery cell includes a current collector 110 and an active material layer 120. The current collector 110 includes a bending region 111, and the bending region 111 is provided with a through hole 112, which penetrates the current collector 110 along its thickness direction. When the cathode electrode is wound into a battery cell, multiple bending segments 113 are formed. Among the multiple bending segments 113, at least one bending region 111 is provided within the bending segment 113 with the largest bending angle. That is, at least one bending region 111 is provided on the current collector 110. When only one bending region 111 is provided, the bending region 111 should be located within the bending segment 113 with the largest bending angle. Figure 1 The innermost bend in the wound cell is where the bending angle is largest, and the risk of breakage is highest. If the end of the cathode electrode 100 inside the wound cell is defined as the beginning end and the end of the cathode electrode 100 outside the cell is defined as the end end, then preferably, at least the bend section 113 closest to the beginning end of the cathode electrode 100 is provided with a bending area 111.
[0037] The anode electrode 200 of the wound cell also includes a current collector and an active material layer. However, the materials used for the current collector and active material layer of the anode electrode 200 differ from those used for the current collector 110 and active material layer 120 of the cathode electrode 100. Although the materials of the active material layer 120 of the cathode electrode 100 and the active material layer of the anode electrode 200 are different, they both have good ductility and are not prone to breakage. Therefore, the main concern is to avoid breakage of the current collector. In actual production, the current collector 110 of the cathode electrode 100 is usually made of aluminum, while the current collector of the anode electrode 200 is usually made of copper. Under the same compaction density, the bending area 111 of aluminum is more prone to breakage. Therefore, it is preferred to set the bending area 111 on the current collector 110 of the cathode electrode 100. The current collector of the anode electrode 200 may or may not have a bending area depending on actual needs.
[0038] When the cathode electrode 100 of this application is in Figure 2 In the unfolded state shown, multiple bends 113 of the cathode electrode 100 are spaced apart along the length of the cathode electrode 100; when the current collector 110 is provided with multiple bends 111, the multiple bends 111 are also spaced apart along the length of the current collector 110, each bend 111 is located within a bend 113, and the number of bends 111 is less than or equal to the number of bends 113; the area of the bend 111 may be equal to or unequal to the area of the bend 113, and usually the area of the bend 111 is smaller than the area of the bend 113.
[0039] What needs to be understood is that Figure 2 , Figure 3 The bent section 113 shown is only for illustrative purposes; the bent section 113 on the actual object cannot be distinguished by the naked eye. The bent area 111 is the area on the current collector 110 where the through hole 112 is provided.
[0040] By providing a through hole 112 penetrating the current collector 110 in the bending region 111, and by positioning the bending region 111 within the bending section 113 of the cathode electrode 100, the stress at the bending section 113 can be released through the through hole 112 when the cathode electrode 100 is bent. This reduces the stress at the bending section 113 when the cathode electrode 100 is bent, thereby reducing the risk of current collector 110 breakage and the probability of cathode electrode 100 breakage, and consequently reducing the probability of cell capacity loss. Furthermore, by providing a through hole 112 penetrating the current collector 110 in the bending region 111, the wound cell can achieve a higher compaction density, thus increasing the energy density of the wound cell.
[0041] Reference Figure 1As shown, the distance A between the bending area 111 closest to the beginning of the current collector 110 and the beginning of the current collector 110 is A = L - L1 - L2 - L3, where L is the width of the wound cell, L1 is the bending width on the first side in the width direction of the wound cell, L2 is the bending width on the second side in the width direction of the wound cell, and L3 is the distance between the beginning of the cathode electrode 100 and the anode electrode 200 structure. For different wound cells, a suitable distance A can be set according to actual needs, which is not limited in this embodiment.
[0042] Once it is ensured that the bending segment 113 closest to the beginning of the cathode electrode 100 has a bending area 111, the other bending segments 113 can have bending areas 111 or not, depending on the actual situation. This is because the bending angles of the other bending segments 113 are all smaller than the bending angle of the bending segment 113 closest to the beginning of the cathode electrode 100. In other words, even if the other bending segments 113 do not have bending areas 111, the probability of breakage of the other bending segments 113 is relatively lower. In a specific embodiment, the other bending segments 113 may all have bending areas 111, or none of the other bending segments 113 may have bending areas 111, or some of the other bending segments 113 may have bending areas 111.
[0043] Reference Figure 2 , Figure 3 As shown, multiple through holes 112 are preferably provided in the bending area 111, and the multiple through holes 112 are preferably spaced apart along the width direction of the current collector 110. The multiple through holes 112 spaced apart along the width direction of the current collector 110 can reduce the probability of the bending area 111 breaking while ensuring the structural strength of the bending area 111. Since the cathode electrode 100 is bent along the length direction, it is preferable that the multiple through holes 112 are spaced apart along the width direction of the current collector 110. After the cathode electrode 100 is wound, the stress at each position in the bending area 111 along the width direction of the current collector 110 is basically the same and uniform. Therefore, it is preferable that the multiple through holes 112 are uniformly spaced along the width direction of the current collector 110, and it is preferable that the diameter of the multiple through holes 112 is equal to reduce manufacturing costs.
[0044] Generally speaking, the number of through holes 112 is positively correlated with the compaction density of the wound cell. The greater the compaction density of the wound cell, the more the number of through holes 112 should be increased, and the area of the holes should also be increased accordingly, so that there is more space for stress release. The smaller the compaction density of the wound cell, the fewer the number of through holes 112 can be, and the area of the holes should also be reduced accordingly.
[0045] It is conceivable that the aperture of the through hole 112 can also be positively correlated with the compaction density of the wound cell. The greater the compaction density of the wound cell, the larger the aperture of the through hole 112 should be, so that there is more space for stress release; correspondingly, the smaller the compaction density of the wound cell, the smaller the aperture of the through hole 112 can be.
[0046] As described above, it is preferable that the diameters of the multiple through holes 112 are equal, but the cross-sectional shapes of the multiple through holes 112 can be specifically set according to the actual situation. For example, the cross-sectional shape of the through holes 112 can be one or more of the following shapes: circular, polygonal, elliptical, etc. The polygonal shape can be a triangle, trapezoid, rhombus, pentagon, hexagon, etc. The multiple through holes 112 can all adopt the same cross-sectional shape, or some of the through holes 112 can adopt the same shape. This embodiment is not limited. In actual production, it is preferable that the multiple through holes 112 adopt the same cross-sectional shape, and all of them are preferably circular, in order to reduce manufacturing difficulty and production cost.
[0047] In the embodiments of this application, the active material layer 120 is coated on the surface of the current collector 110, and both ends of the through hole 112 are covered with the active material layer 120. Specifically, refer to... Figure 4 As shown, the current collector 110 is coated with an active material layer 120 on both sides of its thickness direction, not just the bending area 111. The active material layer 120 coated on the surface of the bending area 111 is no different from the active material layer 120 coated at other locations on the current collector 110. That is, the active material layer 120 coated on the bending area 111 does not need to have holes corresponding to the through holes 112. Therefore, when processing the cathode electrode 100 of this embodiment, the step of coating the active material layer 120 is no different from that of the conventional current collector 110, and no modification to the production line is required, thus reducing processing costs. The active material layer 120 has good ductility, and even when coated on the surface of the bending area 111, the active material layer 120 is not easy to break. Therefore, no additional treatment is required for the active material layer 120 coated on the surface of the bending area 111.
[0048] It is conceivable that the bending area 111 can also be provided with only one through hole 112. A single through hole 112 usually needs to be set as a strip hole. Compared with setting a single through hole 112, the bending area 111 with multiple through holes 112 has higher structural strength and stronger resistance to breakage. In addition, multiple through holes 112 can also better support the active material layer 120.
[0049] As can be seen from the above, multiple through holes 112 are spaced apart along the width direction of the current collector 110. (Referring to...) Figure 2 , Figure 3As shown, multiple through holes 112 whose axes are located on the same plane along the width direction of the current collector 110 are defined as a row. Then, along the length direction of the current collector 110, the bending area 111 may have only one row of through holes 112 or multiple rows of through holes 112. When the bending area 111 has only one row of through holes 112, the fold line of the bending area 111 when it is bent is preferably collinear with the axis of the through hole 112; when the bending area 111 has multiple rows of through holes 112, it is also preferable that the fold line of the bending area 111 when it is bent coincides with one of the rows of through holes 112.
[0050] It is conceivable that when the bending area 111 is provided with multiple rows of through holes 112, the diameters of the through holes 112 in different rows can be set to be equal or unequal, and the cross-sectional shapes of the through holes 112 in different rows can also be set to be the same or different. This embodiment does not impose any limitations.
[0051] It is conceivable that when the bending area 111 is provided with multiple rows of through holes 112, it is preferable that the through holes 112 in two adjacent rows are staggered to improve the structural strength of the current collector 110. At the same time, the staggered arrangement of the two rows of through holes 112 makes it easier to set the distance between the two rows closer, thereby improving the stress relief effect of the bending area 111, further reducing the stress at the bending area 111, and thus making it easier to use a higher compaction density for the wound battery cell to improve the energy density of the wound battery cell.
[0052] In specific embodiments of this application, reference is made to Figure 3 As shown, the aperture D of the through hole 112 is typically limited to between 0.2 mm and 0.5 mm to ensure that the through hole 112 can release stress without affecting the structural strength of the current collector 110. If the aperture of the through hole 112 is too small, it may cause poor stress release effect and high processing difficulty. If the aperture of the through hole 112 is too large, it may affect the structural strength of the current collector 110 and increase the risk of breakage of the current collector 110. At the same time, if the aperture of the through hole 112 is too large, it will also lead to a poor support effect on the active material layer 120, which will cause the active material layer 120 to deform, thereby reducing the capacity of the wound cell.
[0053] In the embodiments of this application, reference is made to Figure 2As shown, along the length of the current collector 110, the width B of the bending area 111 is typically limited to between 1mm and 4mm. The width of the bending area 111 should not be too large, as an excessively large width would affect processing difficulty and efficiency, and too many through-holes 112 on the current collector 110 might also affect the cell's capacity. Furthermore, a bending area width of 1mm to 4mm is sufficient to cover most of the thickness of the current collector 110. Generally speaking, the width of the bending area 111 should be positively correlated with the thickness of the current collector 110. The thicker the current collector 110, the greater the curvature of the bending area 111, and thus the width of the bending area 111 will increase accordingly; conversely, the thinner the current collector 110, the smaller the curvature of the bending area 111, and thus the width of the bending area 111 can be reduced accordingly.
[0054] In embodiments of this application, along the width direction of the current collector 110, the distance between the edge of the current collector 110 and the nearest through hole 112 is 0.2 mm to 1 mm. Specifically, refer to... Figure 3 As shown, the distance D between the edge of the first side of the current collector 110 in the width direction and the nearest through hole 112 is... 11 The distance D between the edge of the second side of the current collector 110 in the width direction and the nearest through hole 112 is 0.2 mm to 1 mm. 12 Also ranging from 0.2mm to 1mm, the preferred distance D 11 and distance D 12 Equal. A reasonably set distance D. 11 and distance D 12 This can prevent the through-hole 112 from damaging the current collector 110, ensuring that the current collector 110 has sufficient structural strength; at the same time, an excessively small distance D 11 and distance D 12 This may increase the risk of lithium plating in the battery cell, and excessive distance D 11 and distance D 12 It is not conducive to stress release.
[0055] In actual production, the distance between the edge of the current collector 110 in the width direction and the nearest through hole 112 can be specifically set according to parameters such as the specific material of the current collector 110 and the size of the through hole 112. For example, the current collector 110 made of pure metal and the current collector 110 made of composite material have different material properties, and the distance between the edge of the current collector 110 in the width direction and the nearest through hole 112 may change. Similarly, the larger the diameter of the through hole 112, the greater the distance between the edge of the current collector 110 in the width direction and the nearest through hole 112 may be, and the smaller the diameter of the through hole 112, the less the distance between the edge of the current collector 110 in the width direction and the nearest through hole 112 may be.
[0056] In the embodiments of this application, reference is made to Figure 3As shown, along the width direction of the current collector 110, the distance D between adjacent through holes 112 is... 21 The distance is 0.1mm to 0.5mm. Specifically, the distance D... 21 An excessively large value may affect stress release, and the distance from D 21 A value that is too small may affect the structural strength of the current collector 110. In actual production, the distance D... 21 The compaction density of the wound cell and the diameter of the through-hole 112 may be limited by parameters such as the compaction density of the wound cell and the diameter of the through-hole 112. For example, if the compaction density of the wound cell is set to be high, the diameter of the through-hole 112 may be increased and the distance D between adjacent through-holes 112 may be reduced accordingly. 21 Conversely, if the compaction density parameter of the wound cell is set too low, the diameter of the through-hole 112 may be reduced accordingly and the distance D between adjacent through-holes 112 may be increased. 21 .
[0057] Furthermore, the distance D between adjacent through holes 112 in different columns 21 They can be set to be the same or different, and this embodiment does not impose any limitations.
[0058] In the embodiments of this application, reference is made to Figure 3 , Figure 4 As shown, along the length of the current collector 110, the distance D between two adjacent rows of through holes 112 is... 22 The distance is 0.1mm to 0.5mm. Specifically, the distance from D... 22 It can be set to distance D 21 Whether they are the same or different is not limited in this embodiment. In actual production, the distance D 22 It may be limited by parameters such as the material of the current collector 110 and the compaction density of the wound cell. For example, for the current collector 110 material with good ductility, the distance from D 22 This may be reduced accordingly, especially for the current collector 110 material with poor ductility, at a distance of D. 22 This may increase accordingly; similarly, if the compaction density parameter of the wound cell is set high, the distance D between adjacent through-hole columns 112 may decrease accordingly. 22 Conversely, if the compaction density parameter of the wound cell is set too low, the distance D between adjacent through holes 112 may be increased accordingly. 22 .
[0059] In order to verify the beneficial effects of the wound battery cell of the first aspect embodiment of this application, this application has designed a corresponding control experiment;
[0060] In all control groups, the same wound battery cell was used. The width L of the wound battery cell was 66 mm and the thickness was 0.6 mm. The distance A between the bending area 111 closest to the beginning of the current collector 110 and the beginning of the current collector 110 was set to 64.8 mm. The distance D between the edge of the current collector 110 and the nearest through hole 112 was... 11 and distance D 12 All are set to 0.5mm, and the distance D between adjacent through holes 112 in the width direction of the current collector 110 is... 21 The distance D between two adjacent columns of through holes 112 along the length direction of the current collector 110 22 All are set to 0.5mm. The main variables are the diameter D of the through hole 112 and the width B of the bending area 111. See the table below for details:
[0061]
[0062] As can be seen from the table above, by providing through holes 112 at the bending area 111, none of the current collectors 110 broke, thus significantly reducing the breakage rate of the cathode electrode 100; the aperture D of the through hole 112 and the width B of the bending area 111 can be varied within the set range, both of which can reduce the probability of breakage at the bending area 111.
[0063] The battery of the second aspect of this application includes the above-described wound cell; since the battery uses the above-described wound cell, it has at least all the beneficial effects of the wound cell, which will not be elaborated here.
[0064] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. In addition, those skilled in the art can combine the different embodiments or examples described in this specification.
[0065] The embodiments of the present utility model have been described in detail above with reference to the accompanying drawings. However, the present utility model is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present utility model.
Claims
1. A wound battery cell, characterized in that, include: Cathode and anode plates; Along the width direction of the wound cell, the starting section of the winding of the cathode electrode and the starting section of the winding of the anode electrode extend and are wound in opposite directions; Along the thickness direction of the wound cell, there is an overlapping area between the projection of the starting section of the winding of the cathode electrode on the horizontal plane and the projection of the starting section of the winding of the anode electrode on the horizontal plane. The cathode electrode includes a current collector and an active material layer. The current collector includes a bending region with multiple through holes. The through holes penetrate the current collector along its thickness direction and are spaced apart along its width direction. The active material layer is coated on the surface of the current collector, and both ends of the through holes are covered with the active material layer. The cathode electrode is wound to form multiple bent sections, and among the multiple bent sections, at least the bent section with the largest bending angle has the bending area.
2. The wound battery cell according to claim 1, characterized in that: Along the length of the current collector, the current collector is provided with a plurality of bending zones at intervals, each bending zone is located within a bending segment, and the number of bending zones is less than or equal to the number of bending segments.
3. The wound battery cell according to claim 1, characterized in that: Along the length of the current collector, the width of the bending area is 1 mm to 4 mm.
4. The wound battery cell according to claim 1, characterized in that: The diameter of the through hole is 0.2 mm to 0.5 mm.
5. The wound battery cell according to claim 1, characterized in that: The multiple through holes have the same cross-sectional shape, and / or the multiple through holes have the same diameter.
6. The wound battery cell according to claim 1, characterized in that: Along the width direction of the current collector, the distance between the edge of the current collector and the nearest through hole is 0.2 mm to 1 mm.
7. The wound battery cell according to claim 1, characterized in that: Along the width direction of the current collector, the distance between adjacent through holes is 0.1 mm to 0.5 mm.
8. The wound battery cell according to claim 1, characterized in that: Along the length of the current collector, the bending area is provided with multiple rows of through holes, and the through holes in adjacent rows are staggered.
9. The wound battery cell according to claim 1, characterized in that: Along the length of the current collector, the bending area is provided with multiple rows of through holes, and the distance between two adjacent rows of through holes is 0.1 mm to 0.5 mm.
10. A battery, characterized in that: Includes the wound battery cell as described in any one of claims 1 to 9.