Winding structure and battery

Abstract

The utility model provides a winding structure and a battery, the winding structure comprises a positive plate, a negative plate, and a first diaphragm and a second diaphragm arranged between the positive plate and the negative plate, the center line of the winding structure in the width direction is the center line of the winding structure, the position where the positive plate is bent for the first time is a first bending area, and the position where the negative plate is bent for the second time is a second bending area. The area where the negative plate is bent for the first time is a second bent area, and the first bent area and the second bent area are located on the two sides of the center line; the second inner paste coating layer located in the first bending area is an inactivation layer, and the content of deintercalated lithium in the inactivation layer is lower than the content of deintercalated lithium in the other second inner paste coating layers. Therefore, in the charging process of the battery formed by the winding structure, lithium ions separated from the inactivation layer towards the end part of the negative plate located at the winding center of the winding structure are reduced, so that lithium separation at the end part of the negative plate is slowed down, the possibility of short circuit of the battery due to lithium separation is further reduced, and the safety of the battery during use is improved.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a winding structure and a battery. Background Art

[0002] In a wound lithium-ion battery, the head end face of the negative electrode sheet at the winding center of the winding structure is far away from the coating of the positive electrode sheet facing it (to prevent the head end face of the negative electrode sheet from touching the positive electrode sheet and bending, a farther space is reserved). Since there is less active material on the head end face of the negative electrode sheet, when the battery is charging, the lithium ions of the positive electrode sheet coating facing the head end face of the negative electrode are not received by enough negative electrode active material after being released, resulting in lithium deposition short circuit in the battery, which seriously affects the safety of the battery. Utility Model Content

[0003] In view of this, the present application provides a winding structure to solve the problem of lithium deposition short circuit in the battery. The present application also provides a battery including the winding structure.

[0004] In order to achieve the above objectives, this application provides the following technical solutions:

[0005] A winding structure, comprising a positive electrode sheet, a negative electrode sheet, and a first separator and a second separator arranged between the positive electrode sheet and the negative electrode sheet, the negative electrode sheet comprising a negative current collector and a first inner paste layer and a first outer paste layer arranged on two opposite surfaces of the negative current collector, the positive electrode sheet comprising a positive current collector and a second inner paste layer and a second outer paste layer arranged on two opposite surfaces of the positive current collector, the second inner paste layer being arranged on a surface close to a winding center of the winding structure, and the second outer paste layer being arranged on a surface away from the winding center,

[0006] The center line of the winding structure in the width direction is the midline of the winding structure, the location where the positive electrode sheet is bent for the first time is the first bending area, the area where the negative electrode sheet is bent for the first time is the second bending area, and the first bending area and the second bending area are located on both sides of the midline;

[0007] The second inner pasting layer located in the first bending area is a deactivated layer, and the deactivated layer has a lower content of deintercalable lithium than the rest of the second inner pasting layer.

[0008] Optionally, the deactivation layer is a laser scanning layer or a physical etching layer.

[0009] Optional,

[0010] The resistance of the deactivation layer is R1, and the resistance of the second inner paste layer is R2, wherein R1 and R2 satisfy: R1≥1.2*R2; and / or,

[0011] The compaction density of the deactivation layer is ρ1, and the compaction density of the second inner paste layer is ρ2, wherein ρ1 and ρ2 satisfy: ρ1≤0.85*ρ2.

[0012] Optionally, the deactivation layer further includes spinel structure lithium cobalt oxide.

[0013] Optionally, the deactivation layer further includes barrier particles, and the barrier particles are located on a surface of the deactivation layer close to an end of the negative electrode sheet.

[0014] Optional,

[0015] In the width direction of the positive electrode sheet, the size of the deactivation layer is equal to the size of the positive electrode sheet; and / or,

[0016] In the length direction of the positive electrode sheet, the size of the deactivation layer is 2 mm-20 mm.

[0017] Optionally, in a direction perpendicular to the straight section of the negative electrode sheet located at the winding center of the winding structure, the deactivation layer and the straight section of the negative electrode sheet overlap, and a dimension of the overlapping area in the width direction of the winding structure is 2 mm-20 mm.

[0018] Optionally, it also includes an insulating layer arranged on the surface of the deactivation layer on one side close to the winding center of the winding structure, and in the direction perpendicular to the positive electrode sheet, the sum of the sizes of the insulating layer and the deactivation layer is less than or equal to the size of the second inner paste layer.

[0019] Optional,

[0020] In the length direction of the positive electrode sheet, the size of the insulating layer is 2 mm to 15 mm, and the size of the insulating layer is smaller than the size of the deactivation layer, and the distance from the insulating layer to the second inner paste layer is 0.5 mm to 5 mm; and / or,

[0021] In the width direction of the positive electrode sheet, the size of the insulating layer is larger than the size of the positive electrode sheet.

[0022] Optionally, the total number of layers of the first separator and the second separator between the straight section of the negative electrode sheet and the straight section of the positive electrode sheet at the winding center of the winding structure is S, where S satisfies: 1≤S≤3.

[0023] Optionally, the minimum distance between the end of the negative electrode sheet at the winding center of the winding structure and the ends of the first separator and the second separator is L1, and the dimension of the straight section of the negative electrode sheet located at the winding center of the winding structure in the width direction of the winding structure is L2, where L1 and L2 satisfy: 5mm≤L1≤L2.

[0024] Optionally, the remaining bending position of the positive electrode sheet is a third bending zone, and the second inner paste layer located in the third bending zone is at least partially an inactivation layer, and / or the second inner paste layer located in the third bending zone is at least partially provided with an insulating layer.

[0025] A battery comprises the winding structure described in any one of the above items.

[0026] The winding structure provided by the present application is such that the second inner paste layer located in the first bending zone is a deactivated layer, and the content of removable lithium in the deactivated layer is lower than the content of removable lithium in the remaining second inner paste layers. In this way, during the charging process of the battery composed of the winding structure, the lithium ions released from the deactivated layer to the end of the negative electrode sheet located at the winding center of the winding structure are reduced, thereby slowing down the lithium deposition at the end of the negative electrode sheet, thereby reducing the possibility of short circuit of the battery due to lithium deposition, and improving the safety of the battery during use. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0028] Figure 1 A front view of the winding structure provided in one embodiment of the present invention;

[0029] Figure 2 for Figure 1 A partial enlarged view of

[0030] Figure 3 A front view of a winding structure in another embodiment;

[0031] Figure 4 for Figure 2 A partial enlarged view of

[0032] Figure 5 A side view of a positive electrode sheet in an unfolded state according to an implementation method;

[0033] Figure 6 is a side view of a positive electrode sheet in an unfolded state in another embodiment;

[0034] Figure 7 is a side view of the negative electrode sheet in an unfolded state;

[0035] Figure 8 is the XRD pattern of the second active material layer;

[0036] Fig. 9 is the XRD pattern of the deactivated layer;

[0037] Fig.10 This is the SEM image of the inactivated area.

[0038] exist Figure 1-Figure 10 middle:

[0039] 1-negative electrode sheet, 2-positive electrode sheet, 3-first separator, 4-second separator, 5-insulating layer;

[0040] 11-negative current collector, 12-first inner paste layer, 13-first outer paste layer, 14-straight section of negative electrode sheet, 15-end of negative electrode sheet, 16-second bending zone, 21-positive current collector, 22-second inner paste layer, 23-second outer paste layer, 24-first bending zone, 25-deactivation layer, 26-straight section of positive electrode sheet, 27-third bending zone. DETAILED DESCRIPTION

[0041] The present application provides a winding structure. The present application also provides a battery comprising the winding structure.

[0042] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0043] like Figures 1 to 10 As shown, the embodiment of the present application provides a winding structure, which can form a battery together with a shell and other components. The winding structure mainly includes a positive electrode sheet 2, a negative electrode sheet 1, and a first separator 3 and a second separator 4 arranged between the positive electrode sheet 2 and the negative electrode sheet 1. The negative electrode sheet includes a negative current collector and a first inner paste layer 12 and a first outer paste layer 13 arranged on two opposite surfaces of the negative current collector. The positive electrode sheet includes a positive current collector and a second inner paste layer 22 and a second outer paste layer 23 arranged on two opposite surfaces of the positive current collector. The second inner paste layer 22 is arranged on a surface close to the winding center of the winding structure, and the second outer paste layer 23 is arranged on a surface away from the winding center. Among them, the center line of the winding structure in the width direction is the center line of the winding structure, the position where the positive electrode sheet is bent for the first time is the first bending area, and the area where the negative electrode sheet is bent for the first time is the second bending area 16. The first bending area and the second bending area 16 are located on both sides of the center line.

[0044] In this embodiment, the second inner paste layer 22 located in the first bending area is a deactivated layer, and the content of removable lithium in the deactivated layer is lower than the content of removable lithium in the remaining second inner paste layers 22. It should be noted that the content of removable lithium in the deactivated layer 25 is lower than the content of removable lithium in the remaining second inner paste layers 22, that is, it is ensured that after the above-mentioned winding structure forms a battery, at least part of the lithium ions in the deactivated layer 25 cannot be released from the deactivated layer 25 and move to the negative electrode sheet 1 during charging. During the charging and discharging process, the lithium ions released from the deactivated layer 25 decrease, and the lithium ions absorbed by the end 15 of the negative electrode sheet close to the deactivated layer 25 decrease, which leads to a decrease in the amount of lithium ions precipitated from the end 15 of the negative electrode sheet located at the winding center of the winding structure, or even no lithium ions are precipitated, thereby avoiding the problem of short circuit of the battery due to lithium precipitation.

[0045] It should be noted that the remaining second inner pasting layers 22 refer to the second inner pasting layers 22 located in other areas outside the first bending area.

[0046] It should also be noted that the winding center of the winding structure refers to the area where the center of the winding structure is located.

[0047] The winding structure of the above structure is achieved by making the second inner paste layer 22 located in the first bending area a deactivated layer, and the content of removable lithium in the deactivated layer is lower than the content of removable lithium in the remaining second inner paste layers 22. In this way, during the charging process of the battery composed of the winding structure, the lithium ions released from the deactivated layer 25 to the end 15 of the negative electrode sheet located at the winding center of the winding structure are reduced, thereby slowing down the lithium deposition at the end of the negative electrode sheet 1, thereby reducing the possibility of short circuit of the battery due to lithium deposition, and improving the safety of the battery during use.

[0048] In some embodiments, the inactivation layer 25 is a laser scanning layer or a physical etching layer.

[0049] It should be noted that the laser scanning layer refers to a layered structure formed by laser scanning the second inner paste layer 22, and the physical etching layer refers to a layered structure formed by physical etching the second inner paste layer 22. The second inner paste layer 22 is subjected to laser scanning, physical etching and other methods to change the conductive agent in the coating of the area or reduce the compaction density of the coating, change the particles of the coating material, or phase change of lithium cobalt oxide to generate spinel lithium cobalt oxide with reduced lithium insertion and extraction ability, thereby reducing the conductivity of the area and reducing or even eliminating the content of lithium that can be inserted and extracted, thereby preventing the corresponding negative electrode area from lithium precipitation.

[0050] In some embodiments, the resistance of the deactivation layer 25 is R1, and the resistance of the second inner paste layer 22 is R2, wherein R1 and R2 satisfy: R1≥1.2*R2; and / or, the compaction density of the deactivation layer 25 is ρ1, and the compaction density of the second inner paste layer 22 is ρ2, wherein ρ1 and ρ2 satisfy: ρ1≤0.85*ρ2. Specifically, the resistance and compaction density of the deactivation layer 25 are set to meet the above range relative to the resistance and compaction density of the second inner paste layer 22, so that the content of deintercalable lithium in the deactivation layer 25 can be lower than the content of deintercalable lithium in the second inner paste layer 22, thereby alleviating lithium deposition at the end 15 of the negative electrode sheet at the winding center of the winding structure, thereby improving the safety of the battery.

[0051] It should be noted that the method is not limited to treating the second inner paste layer 22 by laser scanning and physical etching so that the resistance and compaction density of the deactivated layer 25 obtained after treating the second inner paste layer 22 satisfy the above relationship with that of the untreated second inner paste layer 22. Using other methods to treat the second inner paste layer 22 so that the resistance and compaction density of the deactivated layer 25 obtained after treating the second inner paste layer 22 satisfy the above relationship with that of the untreated second inner paste layer 22 is also within the protection scope of this solution.

[0052] Exemplarily, the resistance R1 of the deactivation layer 25 can be 1.2R2, 1.3R2, 1.4R2, 1.5R2, 1.8R2, 2R2, 3R2, 5R2, etc., where R2 is the resistance of the second inner paste layer 22; the compaction density of the deactivation layer 25 can be 0.85ρ2, 0.82ρ2, 0.8ρ2, 0.75ρ2, 0.7ρ2, 0.6ρ2, 0.5ρ2, etc., where ρ2 is the compaction density of the second inner paste layer 22.

[0053] In some embodiments, the deactivation layer 25 also includes spinel structure lithium cobalt oxide. Specifically, the spinel structure lithium cobalt oxide mainly refers to spinel lithium cobalt oxide, which is caused by high temperature of laser and is a side effect. However, the deintercalation ability of spinel lithium cobalt oxide is not as good as that of conventional layered lithium cobalt oxide. Therefore, although it is a side effect, it can further alleviate the problem of lithium ions moving from the first bending area 24 to the end 15 of the negative electrode sheet, thereby improving the lithium precipitation at the end of the negative electrode sheet 1 corresponding to the first bending area 24.

[0054] In some embodiments, the content of spinel structure lithium cobalt oxide accounts for 5% to 80% of the total lithium cobalt oxide content of the deactivation layer 25. Specifically, since the lithium deintercalation ability of spinel structure lithium cobalt oxide is not as good as that of conventional layered lithium cobalt oxide, the greater the proportion of spinel structure lithium cobalt oxide in the deactivation layer 25, the weaker the ability of the deactivation layer 25 to lose lithium ions during the charging process of the battery composed of the above winding structure, and the stronger the effect of improving the lithium precipitation at the end of the negative electrode sheet 1 corresponding to the first bending area 24.

[0055] For example, the content of the spinel structure lithium cobalt oxide in the total lithium cobalt oxide content of the deactivation layer 25 may be 5%, 10%, 20%, 40%, 50%, 60%, 80%, etc.

[0056] Furthermore, in some embodiments, the deactivation layer 25 further includes blocking particles, and the blocking particles are located on the surface of the deactivation layer 25 near the end of the negative electrode sheet 1. Specifically, the second inner paste layer 22 is formed into the deactivation layer 25 by laser scanning or physical etching, and fine particles are attached to the surface of the deactivation layer 25. During the charging process of the battery composed of the above winding structure, the fine particles will block the lithium ions from moving from the first bending area 24 to the end 15 of the negative electrode sheet, thereby further reducing the amount of lithium ions precipitated from the first bending area 24, and further alleviating the lithium precipitation at the end of the negative electrode sheet 1 corresponding to the first bending portion.

[0057] In some embodiments, in the width direction of the positive electrode sheet 2, the size of the deactivation layer 25 is equal to the size of the positive electrode sheet 2; and / or, in the length direction of the positive electrode sheet 2, the size of the deactivation layer 25 is 2mm-20mm. Specifically, in the width direction of the positive electrode sheet 2, the size of the deactivation layer 25 is equal to the size of the positive electrode sheet 2, that is, by laser scanning and physical etching, the second inner paste layer 22 of the positive electrode sheet 2 in the first bending area 24 close to the end of the negative electrode sheet 1 is completely removed, so that the content of lithium that can be deintercalated in the coating near the end of the negative electrode sheet 1 in the first bending area 24 can be reduced, thereby slowly releasing lithium. In the length direction of the positive electrode sheet 2, the size of the deactivation layer 25 is 2mm-20mm, ensuring that the coating of the end 15 of the negative electrode sheet in the first bending area 24 close to the winding center of the winding structure is all coated with the deactivation layer 25, and the size of the deactivation layer 25 is flexibly set according to winding structures of different specifications and sizes.

[0058] It should be noted that the length direction of the positive electrode sheet 2 refers to Figure 5 The width direction of the positive electrode sheet 2 is not shown in the figure. The width direction of the positive electrode sheet 2 refers to the direction of the positive electrode sheet 2. Figure 5 The direction is indicated by the vertical double-headed arrow A.

[0059] In some embodiments, in the direction of the straight section 14 of the negative electrode sheet located perpendicularly at the winding center of the winding structure, the deactivation layer 25 overlaps with the straight section 14 of the negative electrode sheet, and the size of the overlapping area in the width direction of the winding structure is 2mm-20mm. Specifically, it is ensured that the deactivation layer 25 overlaps with the straight section 14 of the negative electrode sheet located perpendicularly at the winding center of the winding structure, that is, the first bending area 24 and the end of the negative electrode sheet 1 at the winding center of the winding structure are all the deactivation layer 25, which can further ensure the size of the deactivation layer 25 and alleviate or avoid lithium deposition at the end 15 of the negative electrode sheet. Ensuring that the size of the overlapping area in the width direction of the winding structure is 2mm-20mm can ensure that the size of the deactivation layer 25 exceeds the size of the straight section 14 of the negative electrode sheet, further alleviating or avoiding lithium deposition at the end 15 of the negative electrode sheet.

[0060] It should be noted that the direction of the straight section 14 of the negative electrode sheet perpendicular to the winding center of the winding structure refers to Figure 1 The direction indicated by the double-headed arrow B in the winding structure refers to the width direction of the winding structure. Figure 1 The direction is indicated by the double-headed arrow C.

[0061] It should also be noted that the straight section 14 of the negative electrode sheet at the winding center of the winding structure refers to the unbent straight portion of the negative electrode sheet 1 located at the winding center of the winding structure.

[0062] Furthermore, in some embodiments, the winding structure further includes an insulating layer 5 disposed on the surface of the deactivation layer 25 close to the winding center of the winding structure, and in the direction perpendicular to the positive electrode sheet 2, the sum of the sizes of the insulating layer 5 and the deactivation layer 25 is less than or equal to the size of the second inner paste layer 22. Specifically, the insulating layer 5 is disposed on the surface of the deactivation layer 25 close to the winding center of the winding structure, and the insulating layer 5 is attached to the deactivation layer 25. The insulating layer 5 can isolate the lithium ions in the first bending area 24 from moving toward the end 15 of the negative electrode sheet during battery charging. On the basis that the deactivation layer 25 alleviates or avoids lithium deposition at the end 15 of the negative electrode sheet, the insulating layer 5 can further avoid lithium deposition at the end 15 of the negative electrode sheet, thereby avoiding the double protection effect of lithium deposition at the end of the negative electrode sheet 1. And in the direction perpendicular to the positive electrode sheet 2, it is further ensured that the sum of the sizes of the insulating layer 5 and the deactivation layer 25 is less than or equal to the size of the second inner paste layer 22, so as to avoid the increase in the size of the winding structure due to the provision of the insulating layer 5, thereby avoiding the winding structure from generating invalid thickness, thereby avoiding reducing the energy density of the battery composed of the winding structure.

[0063] It should be noted that the direction perpendicular to the positive electrode sheet 2 refers to Figure 5 The direction is indicated by the double-headed arrow D.

[0064] It should be noted that the insulating layer 5 may be an insulating structure such as insulating tape.

[0065] In some embodiments, in the length direction of the positive electrode sheet 2, the size of the insulating layer 5 is ensured to be 2mm to 15mm, and the size of the insulating layer 5 is smaller than the size of the deactivation layer 25. In this way, the insulating layer 5 will not overlap the second inner paste layer 22 next to the deactivation layer 25, which further ensures that the size of the winding structure will not be increased, avoiding affecting the energy density of the battery composed of the winding structure. Further, the distance from the insulating layer 5 to the second inner paste layer 22 is ensured to be 0.5mm to 5mm, and a gap of 0.5mm to 5mm is left between the insulating layer 5 and the second inner paste layer 22, which improves the yield and efficiency of production. The gap can also store electrolyte to increase the battery's liquid retention and increase the cycle life of the lithium-ion battery. In the width direction of the positive electrode sheet 2, the size of the insulating layer 5 is larger than that of the positive electrode sheet 2. With this arrangement, the insulating layer 5 can fully cover the deactivation layer 25 in the width direction of the positive electrode sheet 2, thereby preventing the deactivation layer 25 from being exposed to the outside in the width direction of the positive electrode sheet 2, thereby further preventing lithium ions from moving from the deactivation layer 25 to the negative electrode sheet 1 during charging, thereby preventing lithium deposition on the negative electrode sheet 1.

[0066] It should be noted that the length direction of the positive electrode sheet 2 refers to Figure 5 The width direction of the positive electrode sheet 2 is not shown in the figure. The width direction of the positive electrode sheet 2 refers to the direction of the positive electrode sheet 2. Figure 5 The direction is indicated by the vertical double-headed arrow A.

[0067] In some embodiments, the total number of layers of the first separator 3 and the second separator 4 between the straight section 14 of the negative electrode sheet and the straight section 26 of the positive electrode sheet located at the winding center of the winding structure is S, where S satisfies: 1≤S≤3. Specifically, when the total number of layers of separators between the straight section 14 of the negative electrode sheet and the straight section 26 of the positive electrode sheet is 1, the separator may be the first separator 3 or the second separator 4, when the total number of layers of separators between the straight section 14 of the negative electrode sheet and the straight section 26 of the positive electrode sheet is 2, the separator may be two first separators 3 or two second separators 4 or the first separator and one second separator 4, and when the total number of layers of separators between the straight section 14 of the negative electrode sheet and the straight section 26 of the positive electrode sheet is 3, the separator is preferably one first separator 3 and two second separators 4 or one second separator 4 and two first separators 3. Ensure that the total number of diaphragm layers between the straight section 14 of the negative electrode sheet and the straight section 26 of the positive electrode sheet meets the above range to avoid "Z"-shaped or "U"-shaped overlap between the starting sections of the first diaphragm 3 and the second diaphragm 4 at the beginning of the winding structure, avoid thickening of the winding structure, and avoid reduction in battery energy density.

[0068] It should be noted that the straight section 14 of the negative electrode sheet at the winding center of the winding structure refers to the unbent straight portion of the negative electrode sheet 1 located at the winding center of the winding structure, and the straight section 26 of the positive electrode sheet at the winding center of the winding structure refers to the unbent straight portion of the positive electrode sheet 2 located at the winding center of the winding structure.

[0069] In some embodiments, the minimum distance between the end 15 of the negative electrode sheet at the winding center of the winding structure and the ends of the first diaphragm 3 and the second diaphragm 4 is L1, and the dimension of the straight section 14 of the negative electrode sheet at the winding center of the winding structure in the width direction of the winding structure is L2, where L1 and L2 satisfy: 5mm≤L1≤L2. Ensuring 5mm≤L1 is to prevent the diaphragm from leaking out of the end 15 of the negative electrode sheet at the winding center of the winding structure when the winding structure falls or is vibrated to cause the diaphragm to shrink, thereby preventing the positive and negative electrodes from short-circuiting and causing safety problems; ensuring L1≤L2 is to avoid the diaphragm distance being too long, resulting in the winding structure being thickened, and avoiding affecting the energy density of the battery.

[0070] It should be noted that the minimum distance between the end 15 of the negative electrode sheet at the winding center of the winding structure and the ends of the first separator 3 and the second separator 4 refers to the dimension of the shorter distance from the end 15 of the negative electrode sheet to the ends of the first separator 3 and the second separator 4.

[0071] In some embodiments, the remaining bending position of the positive electrode sheet is the third bending zone 27, and the second inner paste layer 22 located in the third bending zone 27 is at least partially an inactivated layer, and / or the second inner paste layer 22 located in the third bending zone 27 is at least partially provided with an insulating layer. Specifically, the area of ​​the second inner paste layer 22 on the side of the third bending zone 27 close to the winding center of the winding structure is larger than the area of ​​the adjacent first outer paste layer 13, so that during the battery charging process, the second inner paste layer 22 located in the third bending zone 27 releases more lithium ions, while the first outer paste layer 13 close to the third bending zone 27 has no more lithium ion adsorption positions, which leads to lithium deposition on the surface of the first outer paste layer 13. Here, by making at least a portion of the coating on the side of the third bending zone 27 close to the winding center of the winding structure a deactivation layer 25, and / or, at least a portion of the coating on the side of the third bending zone 27 close to the winding center of the winding structure is provided with an insulating layer 5, such a configuration can reduce the content of removable lithium in the coating on the side of the third bending zone 27 close to the winding center of the winding structure, or block the release of lithium ions in the coating on the side of the third bending zone 27 close to the winding center of the winding structure, thereby alleviating lithium deposition on the surface of the first outer coating layer 13, or even avoiding lithium deposition on the surface of the first outer coating layer 13.

[0072] A battery comprises any one of the above winding structures. The beneficial effects of the winding structure on the battery can be found in the above content and will not be described in detail here.

[0073] The basic principles of the present application are described above in conjunction with specific embodiments. However, it should be noted that the advantages, strengths, effects, etc. mentioned in the present application are only examples and not limitations, and it cannot be considered that these advantages, strengths, effects, etc. are required by each embodiment of the present application. In addition, the specific details disclosed above are only for the purpose of illustration and ease of understanding, not for limitation, and the above details do not limit the present application to being implemented by adopting the above specific details.

[0074] The block diagrams of the devices, apparatuses, equipment, and systems involved in this application are only illustrative examples and are not intended to require or imply that they must be connected, arranged, and configured in the manner shown in the block diagram. As will be appreciated by those skilled in the art, these devices, apparatuses, equipment, and systems can be connected, arranged, and configured in any manner. Words such as "including", "comprising", "having", etc. are open words, referring to "including but not limited to", and can be used interchangeably with them. The words "or" and "and" used here refer to the words "and / or" and can be used interchangeably with them, unless the context clearly indicates otherwise. The words "such as" used here refer to the phrase "such as but not limited to", and can be used interchangeably with them.

[0075] It should also be noted that in the apparatus, device and method of the present application, each component or each step can be decomposed and / or recombined. Such decomposition and / or recombination should be regarded as equivalent solutions of the present application.

[0076] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use the present application. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects without departing from the scope of the present application. Therefore, the present application is not intended to be limited to the aspects shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

[0077] It should be understood that the qualifiers "first", "second", "third", "fourth", "fifth" and "sixth" used in the description of the embodiments of the present application are only used to more clearly explain the technical solutions and cannot be used to limit the scope of protection of the present application.

[0078] The above description has been given for the purpose of illustration and description. In addition, this description is not intended to limit the embodiments of the present application to the forms disclosed herein. Although multiple example aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, changes, additions and sub-combinations thereof.

Claims

1. A winding structure, comprising a positive electrode sheet, a negative electrode sheet, and a first separator and a second separator disposed between the positive electrode sheet and the negative electrode sheet, wherein the negative electrode sheet comprises a negative current collector and a first inner paste layer and a first outer paste layer disposed on opposite surfaces of the negative current collector, wherein the positive electrode sheet comprises a positive current collector and a second inner paste layer and a second outer paste layer disposed on opposite surfaces of the positive current collector, wherein the second inner paste layer is disposed on a surface close to a winding center of the winding structure, and the second outer paste layer is disposed on a surface away from the winding center, wherein: The center line of the winding structure in the width direction is the midline of the winding structure, the location where the positive electrode sheet is bent for the first time is the first bending area, the area where the negative electrode sheet is bent for the first time is the second bending area, and the first bending area and the second bending area are located on both sides of the midline; The second inner pasting layer located in the first bending area is a deactivated layer, and the deactivated layer has a lower content of deintercalable lithium than the rest of the second inner pasting layer.

2. The winding structure according to claim 1, characterized in that: The deactivation layer is a laser scanning layer or a physical etching layer.

3. The winding structure according to claim 1 or 2, characterized in that: The resistance of the deactivation layer is R1, and the resistance of the second inner paste layer is R2, wherein R1 and R2 satisfy: R1≥1.2*R2; and / or, The compaction density of the deactivation layer is ρ1, and the compaction density of the second inner paste layer is ρ2, wherein ρ1 and ρ2 satisfy: ρ1≤0.85*ρ2.

4. The winding structure according to claim 3, characterized in that: The deactivation layer also includes spinel structure lithium cobalt oxide.

5. The winding structure according to claim 2, characterized in that: The deactivation layer further includes barrier particles, and the barrier particles are located on a surface of the deactivation layer close to an end of the negative electrode sheet.

6. The winding structure according to claim 1, characterized in that: In the width direction of the positive electrode sheet, the size of the deactivation layer is equal to the size of the positive electrode sheet; and / or, In the length direction of the positive electrode sheet, the size of the deactivation layer is 2 mm-20 mm.

7. The winding structure according to claim 1, characterized in that: In a direction perpendicular to the straight section of the negative electrode sheet located at the winding center of the winding structure, the deactivation layer and the straight section of the negative electrode sheet overlap, and a dimension of the overlapping area in the width direction of the winding structure is 2 mm-20 mm.

8. The winding structure according to claim 1, characterized in that: It also includes an insulating layer arranged on the surface of the deactivation layer on one side close to the winding center of the winding structure, and in the direction perpendicular to the positive electrode sheet, the sum of the sizes of the insulating layer and the deactivation layer is less than or equal to the size of the second inner paste layer.

9. The winding structure according to claim 8, characterized in that: In the length direction of the positive electrode sheet, the size of the insulating layer is 2 mm to 15 mm, and the size of the insulating layer is smaller than the size of the deactivation layer, and the distance from the insulating layer to the second inner paste layer is 0.5 mm to 5 mm; and / or, In the width direction of the positive electrode sheet, the size of the insulating layer is larger than the size of the positive electrode sheet.

10. The winding structure according to claim 1, characterized in that: The total number of layers of the first separator and the second separator between the straight section of the negative electrode sheet and the straight section of the positive electrode sheet located at the winding center of the winding structure is S, where S satisfies: 1≤S≤3.

11. The winding structure according to claim 10, characterized in that: The minimum distance between the end of the negative electrode sheet at the winding center of the winding structure and the ends of the first separator and the second separator is L1, and the dimension of the straight section of the negative electrode sheet located at the winding center of the winding structure in the width direction of the winding structure is L2, where L1 and L2 satisfy: 5mm≤L1≤L2.

12. The winding structure according to claim 1, characterized in that: The remaining bending position of the positive electrode sheet is the third bending zone, and the second inner paste layer located in the third bending zone is at least partially an inactivation layer, and / or the second inner paste layer located in the third bending zone is at least partially provided with an insulating layer.

13. A battery, characterized in that: It comprises a winding structure as described in any one of claims 1 to 12.

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