Jelly roll, cylindrical battery and battery pack
By setting elastic and flexible zones on the winding tape of the core, the problems of core expansion and uneven stress caused by silicon anode are alleviated, thereby improving the performance and lifespan of lithium-ion batteries.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- SHANGHAI XUANYI NEW ENERGY DEV CO LTD
- Filing Date
- 2026-01-09
- Publication Date
- 2026-07-16
AI Technical Summary
During the charging and discharging process, the volume expansion of the silicon anode in lithium-ion batteries leads to core expansion and uneven stress, which affects the battery's cycle life and performance.
An elastic zone and a flexible zone are set on the winding tape of the core. The elastic zone buffers the uneven stress of the outermost layer of the core and reduces the uneven strain between the core and the battery casing. At the same time, a flexible zone is set on the current collector to relieve the stress between the electrode layers.
It improves battery performance and efficiency, extends battery life, and reduces problems such as uneven electrolyte distribution and stress between electrode layers.
Smart Images
Figure CN2026071728_16072026_PF_FP_ABST
Abstract
Description
A type of wound core, cylindrical battery and battery pack
[0001] This application claims priority to Chinese Patent Application No. 202510043767.0, filed on January 10, 2025, entitled "A Chip, Cylindrical Battery and Battery Pack". Technical Field
[0002] This application relates to the field of battery technology, and in particular to a wound core, cylindrical battery, and battery pack. Background Technology
[0003] With the rapid development of lithium-ion batteries in power and energy storage systems, the demand for high-energy-density lithium-ion batteries continues to grow. At the individual cell level, the energy density of lithium-ion batteries is mainly determined by the positive and negative electrode materials. Currently, the energy density of ternary cathode materials has reached its limit. Therefore, in order to further improve the energy density of lithium-ion batteries, researchers and engineers have begun to focus on improving negative electrode materials.
[0004] In recent years, silicon anodes have attracted much attention due to their higher theoretical specific capacity compared to traditional carbon anodes. However, silicon anodes are prone to volume expansion during charge and discharge. Specifically, this expansion is caused by the lithium-silicon alloy formed during the alloying reaction, leading to increased internal stress within the core; and the re-intercalation of lithium ions into the positive electrode causes structural collapse of the anode electrode. These phenomena cause overall core expansion and collapse, resulting in electrode structural damage, battery capacity degradation, and ultimately, a decrease in battery cycle life.
[0005] To address the stress problem caused by core expansion, the existing technologies mainly employ the following three solutions:
[0006] Firstly, the structure of the central hole can be improved. For example, Chinese patent CN218887283U9 discloses a cylindrical battery that defines the range of the central hole diameter as r / cell diameter R: 7% ≤ r / R ≤ 33%, 40mm ≤ R ≤ 80mm. This solution can avoid the risk of active material shedding or electrode breakage under high stress, and the winding of the central hole can provide a buffer for cell expansion, further reducing the risk of electrode breakage.
[0007] Secondly, there is the core zoning design, which adjusts the stress within the core by zoning. For example, Chinese patent CN116826142A discloses a core, its preparation method, and a cylindrical battery, involving a layered nested core design. The core consists of n core units (n≥2) sequentially nested from the inside out. Each core unit comprises a first separator, a negative electrode, a second separator, and a positive electrode wound sequentially. The electrode formulation and thickness within each core unit are also specified. This design can buffer excessive stress in the inner ring of the core, significantly improving electrode breakage and material loss, while simultaneously increasing the battery's energy density while maintaining battery performance.
[0008] Third, optimize the design of the positive electrode sheet by incorporating a stress-buffered layer between the current collector and the tab to prevent the aluminum foil from breaking due to the shearing action of the tab. For example, Chinese patent CN108281609A discloses a positive electrode sheet with tabs, its preparation method, and a lithium-ion battery containing the positive electrode sheet. The positive electrode sheet includes a current collector, a stress-buffered conductive layer with pores, tabs, and adhesive tape. The surface of the current collector has a positive electrode slurry layer and a blank area. Within the blank area, the stress-buffered conductive layer, tabs, and adhesive tape are arranged sequentially from bottom to top. The stress-buffered conductive layer is an elastic double-sided conductive tape with a thickness of 30μm-50μm. It is a composite material made of an elastic adhesive and any one or at least two of the following: carbon powder, graphene, or carbon nanotubes. The surface structure is pyramidal or pyramid-like. This design can release the shear stress of the positive electrode tabs on the aluminum foil, preventing the aluminum foil from cracking during cycling and improving cycle performance.
[0009] However, while these solutions alleviate the core expansion and stress problems caused by silicon anodes to some extent, lithium-ion batteries still experience core expansion during charging and discharging. This expansion, coupled with the constraint of the rigid outer shell, leads to point contact between the outer layer of the core and the inner wall of the steel shell during the initial stages of cycling. This point contact pulls on other areas of the core, resulting in uneven strain across the entire core. Summary of the Invention
[0010] To address the above technical problems, this application provides a core for buffering battery stress; another aspect is a cylindrical battery; and yet another aspect is a battery pack.
[0011] The technical problem solved by this application can be achieved using the following technical solutions:
[0012] A wound core, comprising a positive electrode sheet, a first separator, a negative electrode sheet, and a second separator stacked and wound sequentially, and further comprising:
[0013] The take-up tape is attached to the second diaphragm, starting from the take-up end of the negative electrode sheet and ending at the take-up end of the second diaphragm.
[0014] The winding tape has an elastic zone, which is located on the side of the winding tape away from the negative electrode sheet.
[0015] Preferably, the take-up tape further includes a base layer and a discontinuity zone, with the discontinuity zone and the elastic zone alternately arranged on the base layer.
[0016] Preferably, the elastic region includes:
[0017] The first elastic zone is located near the take-up terminal of the negative electrode sheet; and / or
[0018] The second and third elastic zones are located between the winding end of the negative electrode sheet and the outermost circumference of the core; and / or
[0019] The fourth elastic zone is located on the outermost circumference of the core.
[0020] Preferably, the length of the fourth elastic region is greater than the lengths of the first elastic region, the second elastic region, and the third elastic region, respectively.
[0021] Preferably, the length of the first elastic region is 10mm-15mm; and / or
[0022] The length of the second elastic zone is 10mm-15mm; and / or
[0023] The length of the third elastic zone is 10mm-15mm; and / or
[0024] The length of the fourth elastic zone is 130mm-140mm.
[0025] Preferably, the positive electrode sheet is provided with a current collector, and the current collector is provided with multiple flexible regions, which are distributed at intervals along the circumferential direction.
[0026] Preferably, the flexible region includes:
[0027] The first flexible zone is located in the inner layer of the core; and / or
[0028] The second flexible zone is located in the middle layer of the core; and / or
[0029] The third flexible zone is located on the outer layer of the core.
[0030] Preferably, the flexible region is a porous conductive carbon layer.
[0031] A second aspect of this application is to provide a cylindrical battery, which includes a battery casing and a winding core as described above is installed inside the battery casing.
[0032] A third aspect of this application is to provide a battery pack comprising a plurality of cylindrical batteries as described above.
[0033] The advantages or beneficial effects of the technical solution in this application are as follows:
[0034] This application improves battery performance by providing an elastic zone on the side of the winding tape away from the negative electrode sheet, which can buffer the uneven stress on the outermost layer of the core and reduce the uneven strain generated when the core contacts the battery casing. Attached Figure Description
[0035] Figure 1 is a schematic diagram of the tape winding process in a preferred embodiment of this application;
[0036] Figure 2 is a schematic diagram of the current collector in a preferred embodiment of this application; in Figures 1 and 2, D1 represents the end direction of the negative electrode sheet, and D2 represents the outermost circumferential direction of the winding core;
[0037] Figure 3 is a schematic diagram of the current collector in a preferred embodiment of this application;
[0038] Figure 4 is a schematic diagram of the current collector in a preferred embodiment of this application;
[0039] Figure 5 is a schematic diagram of the current collector in a preferred embodiment of this application;
[0040] Figure 6 is a schematic diagram of the current collector in a preferred embodiment of this application; wherein, D3 represents the inner layer direction of the core and D4 represents the outer layer direction of the core.
[0041] Explanation of reference numerals in the attached drawings: 1. Core; 2. First diaphragm; 3. Negative electrode sheet; 4. Positive electrode sheet; 40. Current collector; 41. Positive electrode slurry area; 421. First flexible area; 422. Second flexible area; 423. Third flexible area; 5. Rewinding tape; 50. Base layer; 51. First elastic area; 52. First discontinuous area; 53. Second elastic area; 54. Second discontinuous area; 55. Third elastic area; 56. Third discontinuous area; 57. Fourth elastic area; 6. Second diaphragm. Detailed Implementation
[0042] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.
[0043] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.
[0044] Regarding existing lithium-ion batteries, the applicant discovered that as the cycling process continues, the stress between the electrode layers increases continuously. In addition, due to the constraint of the steel shell, the shrinkage ability of the core becomes weaker, resulting in the maximum radial stress on the outermost layer of the core and the maximum circumferential stress at the center, ultimately causing uneven electrolyte distribution and overall stress unevenness in the core.
[0045] The present application will be further described below with reference to the accompanying drawings and specific embodiments, but this is not intended to limit the scope of the application.
[0046] Referring to Figure 1, in a preferred embodiment of this application, based on the aforementioned problems existing in the prior art, a winding core is provided. The winding core 1 is formed by sequentially stacking and winding a positive electrode sheet 4, a first separator 2, a negative electrode sheet 3, and a second separator 6. The winding core 1 further includes:
[0047] Take-up tape 5 is attached to the second diaphragm 6, starting from the take-up end of the negative electrode sheet 3 and ending at the take-up end of the second diaphragm 6.
[0048] An elastic zone is provided on the winding tape 5, and the elastic zone is located on the side of the winding tape 5 away from the negative electrode sheet 3.
[0049] Specifically, to address the issue of core expansion caused by the silicon anode, this embodiment of the application provides spaced elastic zones on the side of the winding tape 5 away from the anode sheet 3. Through the elastic effect of these phased elastic zones, the uneven stress on the outermost layer of the core is buffered, thereby reducing the uneven strain generated when the core contacts the battery casing.
[0050] In a preferred embodiment, the winding tape 5 further includes a base layer 50 and a discontinuity zone, with the discontinuity zone and the elastic zone alternately arranged on the base layer 50.
[0051] In this embodiment, the base layer 50 is made of PI or PET material.
[0052] Interruption zones are provided between the elastic zones. These interruption zones can be blank or unused areas, or other materials that can promote wetting, such as, but not limited to, polar materials, perfluorophenyl azide compounds (PFPA), and surface-treated adhesive tape films.
[0053] During high-rate charging and discharging, the blank areas left on the tape promote the flow, wetting and reflux of electrolyte within the core, solving the problems of electrolyte being difficult to exist in the central hole and difficult to reflux to the electrode layers, thereby improving battery performance and efficiency.
[0054] The elastic zone is made of thermoplastic polyurethane (TPU), which has excellent elasticity, chemical resistance, and good mechanical properties, and can be laminated with PI or PET materials.
[0055] In a preferred embodiment, the number of elastic regions does not exceed four.
[0056] In this embodiment, the take-up tape 5 is attached to the outermost second diaphragm 6, starting from the take-up end of the negative electrode sheet 3 and ending at the take-up end of the second diaphragm 6.
[0057] The take-up tape 5 has a base layer 50, elastic zones, and discontinuous zones. The number of elastic zones is ≤4. Discontinuous zones are set between the elastic zones, and the number of elastic zones is one more than the number of discontinuous zones.
[0058] In a preferred embodiment, the elastic region includes:
[0059] The first elastic zone 51 is located near the winding terminal of the negative electrode 3; or...
[0060] The second elastic region 53 and the third elastic region 55 are located between the winding end of the negative electrode sheet 3 and the outermost circumference of the core 1; or,
[0061] The fourth elastic zone 57 is located on the outermost circumference of the core 1.
[0062] In another embodiment, the elastic region may also be configured as follows:
[0063] A first elastic zone is located near the winding end of the negative electrode sheet; and / or
[0064] The second and third elastic regions are located between the winding end of the negative electrode sheet and the outermost circumference of the core; and
[0065] The fourth elastic zone is located on the outermost circumference of the core.
[0066] This application embodiment takes the setting of four elastic regions as an example, such as the first elastic region 51, the second elastic region 53, the third elastic region 55 and the fourth elastic region 57.
[0067] The first elastic zone 51 is located near the winding end of the negative electrode 3.
[0068] The second elastic region 53 and the third elastic region 55 are located between the outermost circumference and the winding end of the negative electrode sheet.
[0069] The fourth elastic zone 57 is located on the outermost circumference, that is, on the last circumference of the core. The fourth elastic zone 57 serves as an elastic layer between the outermost core and the steel shell. When the outermost core contacts the steel shell, the elastic layer can reduce the uneven strain caused by the contact between the core and the steel shell.
[0070] In a preferred embodiment, the length of the fourth elastic region 57 is greater than the lengths of the first elastic region 51, the second elastic region 53, and the third elastic region 55.
[0071] Specifically, in this embodiment, at least one elastic region is located on the outermost circumference, and other elastic regions are located between the outermost circumference and the end of the negative electrode 3. The length of the elastic region on the outermost circumference is greater than the length of the other elastic regions located between the outermost circumference and the end of the negative electrode 3. When the outermost layer of the core contacts the steel shell, the elastic layer can mitigate the uneven strain caused by the contact between the core and the steel shell.
[0072] For clarity, the length in this application refers to the dimension of the core in its winding direction (or circumferential direction), and the width refers to the dimension of the core in its axial direction.
[0073] In a preferred embodiment, the length dimensions of the first elastic region 51, the second elastic region 53, the third elastic region 55, and the fourth elastic region 57 satisfy at least one of the following conditions:
[0074] The length of the first elastic region 51 is 10mm-15mm; the length of the second elastic region 53 is 10mm-15mm;
[0075] The length of the third elastic zone 55 is 10mm-15mm;
[0076] The length of the fourth elastic zone 57 is 130mm-140mm.
[0077] In an optional embodiment, the length dimensions of the first elastic region 51, the second elastic region 53, the third elastic region 55, and the fourth elastic region 57 satisfy all the above conditions.
[0078] In this embodiment, the total length of the winding tape 1 is 130mm-230mm, the width is 60mm-70mm, and the thickness is 40μm-50μm.
[0079] In this embodiment, the width of the elastic zone is the same as the width of the winding tape 1.
[0080] The first elastic region 51, the second elastic region 53, and the third elastic region 55 all have the same length, and their width and thickness are also the same.
[0081] Specifically, the lengths of the first elastic region 51, the second elastic region 53, and the third elastic region 55 are 10mm-15mm, the widths are 60mm-70mm, and the thicknesses are 5μm-10μm, respectively.
[0082] The fourth elastic zone has a length of 130mm-140mm, a width of 60mm-70mm, and a thickness of 5μm-10μm.
[0083] Furthermore, the discontinuities include:
[0084] The first discontinuity zone 52 is located between the first elastic zone 51 and the second elastic zone 53;
[0085] The second discontinuity zone 54 is located between the second elastic zone 53 and the third elastic zone 55;
[0086] The third discontinuity zone 56 is located between the third elastic zone 55 and the fourth elastic zone 57.
[0087] Specifically, the elastic zones and discontinuous zones are distributed at intervals, with discontinuous zones between the four elastic zones. The discontinuous zones are blank areas in the base layer. For example, a first discontinuous zone 52 is set between the first elastic zone 51 and the second elastic zone 53, a second discontinuous zone 54 is set between the second elastic zone 53 and the third elastic zone 55, and a third discontinuous zone 56 is set between the third elastic zone 55 and the fourth elastic zone 57.
[0088] During high-rate charging and discharging, the electrolyte is difficult to remain in the central hole and difficult to flow back to the electrode layers. At this time, a blank area is set on the outermost layer of the core to facilitate electrolyte flow, wetting, or electrolyte return.
[0089] Specifically, the lengths of the first discontinuity zone 52, the second discontinuity zone 54, and the third discontinuity zone 56 are 10mm-15mm and 55mm-65mm, respectively.
[0090] In a preferred embodiment, the positive electrode 4 is provided with a current collector 40, and the current collector 40 is provided with multiple flexible regions, which are distributed at intervals along the circumferential direction.
[0091] Specifically, current collector 40 is the positive electrode current collector. From the perspective of cell electrode design, the N / P ratio (the margin between the negative electrode capacity and the positive electrode capacity) is usually greater than 1 to ensure that the negative electrode can accommodate the lithium ions released from the positive electrode and avoid lithium plating caused by excessive lithium ions during charging. From the perspective of the negative electrode material of lithium-ion batteries, high-energy-density silicon negative electrodes (silicon-carbon or silicon-oxygen materials) are usually used to improve the energy density of the entire battery. However, the silicon negative electrode generates a large volume expansion during charging and discharging, which causes the electrolyte between the positive and negative electrode plates to be squeezed out. The poor contact between the electrode and the electrolyte liquid-solid-liquid interface affects the battery cycle performance.
[0092] Considering the above two aspects, the flexible region is located on the positive current collector.
[0093] In this embodiment, flexible areas are provided at intervals along the circumferential direction on the current collector 40. These flexible areas act as buffers to alleviate the stress in the outer, middle, and inner layers of the core.
[0094] In this embodiment, the core 1 is a jelly-like core. For a cylindrical lithium-ion jelly-like core, the flexible region is located on the upper layer of the positive electrode current collector.
[0095] There is no filler or slurry between the flexible area and the positive current collector.
[0096] In this embodiment, the flexible region does not contain positive electrode active material.
[0097] In this embodiment, the flexible region also does not contain negative electrode active material.
[0098] The flexible region and the positive electrode slurry region 41 (composed of positive electrode active material, binder, conductive agent, solvent, etc.) are adjacent to each other and are distributed alternately.
[0099] The flexible areas are spaced apart along the circumference of the jelly-like core.
[0100] In a preferred embodiment, the number of flexible regions is not less than 3, i.e., ≥3.
[0101] In core design, the number of flexible regions can be determined by both the total electrode length and the desired energy density. Since the flexible regions do not contain positive or negative electrode active materials, they avoid bearing stress from adjacent electrode layers, thus enhancing the overall structural stability of the core. However, the presence of flexible regions also reduces the proportion of active material, which in turn affects the core's energy density. Therefore, in practical designs, the number of flexible regions can be adjusted according to specific design requirements.
[0102] To achieve optimal performance, it is necessary to comprehensively consider the balance between the number of flexible areas and the structural performance and energy density of the core. If the number is too large, it will lead to a lower energy density of the battery.
[0103] In a preferred embodiment, the flexible region includes:
[0104] The first flexible area 421 is located in the inner layer of the core 1;
[0105] The second flexible zone 422 is located in the middle layer of the core 1;
[0106] The third flexible zone 423 is located on the outer layer of the core 1.
[0107] This application example illustrates the use of three flexible regions, such as the first flexible region 421, the second flexible region 422, and the third flexible region 423, which are located in the inner layer, middle layer, and outer layer of the jelly-like core, respectively, to achieve a balance between structural stability and energy density.
[0108] In a preferred embodiment, the flexible region is a porous conductive carbon layer.
[0109] In lithium-ion batteries, current collector 40 mainly refers to metal foil, such as copper foil or aluminum foil, and may also include tabs.
[0110] In this embodiment, a porous conductive carbon layer is coated on the surface of the current collector 40. The flexible area is the coating area of the conductive carbon layer. The conductive carbon layer is porous, which further improves the conductivity and electrochemical performance of the current collector 40.
[0111] Porous conductive carbon layers possess excellent electrical conductivity and a good pore structure, which can not only effectively improve the charging and discharging efficiency of batteries, but also promote electrolyte penetration and ion transport.
[0112] Furthermore, the thickness of the porous conductive carbon layer is 1 μm to 5 μm.
[0113] Specifically, in this embodiment, only a porous conductive carbon layer is coated on the current collector 40, and the thickness of the conductive carbon layer is within a few micrometers.
[0114] The thickness of the conductive carbon layer is preferably 1 to 5 μm to ensure the best balance between conductivity and mechanical strength, avoiding the increase in battery internal resistance and decrease in energy density caused by excessive thickness, or the poor conductivity and structural fragility caused by excessive thinness.
[0115] As an example and not a limitation, the thickness of the conductive carbon layer can be 1μm, 1.5μm, 2μm, 2.5μm, 3μm, 3.5μm, 4μm, 4.5μm, 5μm, etc.
[0116] In this embodiment, the length of the conductive carbon layer is the same as the width of the positive electrode sheet; the width of the conductive carbon layer is the circumferential length of the positive electrode sheet, which is several millimeters.
[0117] In this embodiment, the width of the third flexible region 423 is much larger than the width of the first flexible region 421 and the width of the second flexible region 432; the width of the second flexible region 432 is larger than the width of the first flexible region 431, thereby increasing conductivity.
[0118] Preferably, the width WI of the first flexible region 431 is 1mm to 2mm. By way of example and not limitation, WI can be 1mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, 1.6mm, 1.7mm, 1.8mm, 1.9mm, 2mm, etc.
[0119] The width WM of the second flexible zone 432 is 3mm to 10mm. As an example and not a limitation, WM can be 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, etc.
[0120] The width WO of the third flexible zone 433 is 10mm to 18mm. As an example and not a limitation, WO can be 10mm, 11mm, 12mm, 13mm, 14mm, 15mm, 16mm, 17mm, 18mm, etc.
[0121] In a preferred embodiment, the porous conductive carbon layer is made of carbon fiber.
[0122] Specifically, in this embodiment, carbon fiber is used as the material for the conductive carbon layer. Carbon fiber has a high elastic modulus, which can alleviate interlayer stress generated between electrodes during the charging and discharging process, making it suitable for high-curvature electrodes with a jelly-like core. Simultaneously, carbon fiber has excellent conductivity, which can improve the overall electron transport efficiency of the core and ensure a continuous electron transport path between the flexible area and the adjacent positive electrode slurry layer.
[0123] This application also provides a cylindrical battery, which includes a battery casing (such as the steel casing described above) and a core for buffering battery stress as described above is installed inside the battery casing.
[0124] Preferably, the cylindrical battery is a lithium-ion cylindrical battery.
[0125] Specifically, for the outer layer of the core, taking the winding tape as an example, elastic zones and discontinuous zones are designed in stages on the winding tape 10. The elastic zones can resist uneven strain generated in the core during charge-discharge cycles. The discontinuous zones between the elastic zones facilitate electrolyte flow, ensuring uniform electrolyte penetration within the core and further improving battery performance.
[0126] For the outer, inner and middle layers of the core, taking the current collector 40 as the object, a flexible area is set on the current collector 40 to increase the conductivity; at the same time, it alleviates the expansion stress of the interlayer electrodes caused by the charging and discharging process, reduces the potential damage between the electrodes, and thus extends the service life of the battery.
[0127] The embodiments of this application do not require the addition of additional external structures to the cylindrical battery, thus ensuring the integrity of the electrode structure and the superior performance of the battery.
[0128] The advantages or beneficial effects of the above technical solution are as follows: By arranging elastic regions and discontinuous regions alternately on the tape, the elastic regions can reduce the uneven strain generated when the core contacts the battery casing; at the same time, during high-rate charging and discharging, the discontinuous regions promote the flow, wetting and reflux of the electrolyte, solving the problem that the electrolyte is difficult to exist in the central hole and difficult to reflux to the electrode layers, thereby improving the performance and efficiency of the battery.
[0129] The above are merely preferred embodiments of this application and do not limit the implementation methods and protection scope of this application. Those skilled in the art should realize that any equivalent substitutions and obvious changes made using the content of this specification and illustrations should be included within the protection scope of this application.
Claims
1. A type of winding core, characterized in that, The wound core (1) is formed by sequentially stacking and winding a positive electrode sheet (4), a first separator (2), a negative electrode sheet (3), and a second separator (6). The wound core (1) also includes: Take-up tape (5), the take-up tape (5) is pasted on the second diaphragm (6) and starts from the take-up end of the negative electrode sheet (3) and ends at the take-up end of the second diaphragm (6); The take-up tape (5) is provided with an elastic area, which is located on the side of the take-up tape (5) away from the negative electrode sheet (3).
2. The winding core according to claim 1, characterized in that, The take-up tape (5) also includes a base layer (50) and a discontinuity zone, wherein the discontinuity zone and the elastic zone are alternately arranged on the base layer (50).
3. The winding core according to claim 1, characterized in that, The elastic region includes: The first elastic region (51) is located near the winding terminal of the negative electrode sheet; or, The second elastic region (53) and the third elastic region (55) are located between the winding end of the negative electrode sheet (3) and the outermost circumference of the core (1); or, The fourth elastic zone (57) is located on the outermost circumference of the core (1).
4. The winding core according to claim 1, characterized in that, The elastic region includes: The first elastic region (51) is located near the winding end of the negative electrode (3); and / or The second elastic region (53) and the third elastic region (55) are located between the winding end of the negative electrode sheet (3) and the outermost circumference of the core (1); and The fourth elastic zone (57) is located on the outermost circumference of the core (1).
5. The winding core according to claim 4, characterized in that, The length of the fourth elastic region (57) is greater than the lengths of the first elastic region (51), the second elastic region (53), and the third elastic region (55).
6. The winding core according to claim 3, characterized in that, The length of the first elastic region (51) is 10mm-15mm; or, The length of the second elastic region (53) is 10mm-15mm; or, The length of the third elastic region (55) is 10mm-15mm; or, The length of the fourth elastic zone (57) is 130mm-140mm.
7. The winding core according to claim 1, characterized in that, The positive electrode (4) is provided with a current collector (40), and the current collector (40) is provided with multiple flexible regions, which are distributed at intervals along the circumferential direction.
8. The winding core according to claim 7, characterized in that, The flexible region includes: The first flexible region (421) is located in the inner layer of the core (1); or The second flexible area (422) is located in the middle layer of the core (1); or The third flexible region (423) is located on the outer layer of the core (1).
9. The winding core according to claim 7, characterized in that, The plurality of flexible regions include: The first flexible region (421) is located in the inner layer of the core (1); The second flexible area (422) is located in the middle layer of the core (1); The third flexible region (423) is located on the outer layer of the core (1).
10. The winding core according to claim 7, characterized in that, The flexible region is a porous conductive carbon layer.
11. A cylindrical battery, characterized in that, The cylindrical battery includes a battery casing, and a winding core as described in any one of claims 1-10 is installed inside the battery casing.
12. A battery pack, characterized in that, It includes multiple cylindrical batteries as described in claim 11.