Electrode assembly and battery cell
Patent Information
- Application Number
- CN202521826467.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-26
- Publication Date
- 2026-09-08
- Estimated Expiration
- 2035-08-26
AI Technical Summary
[0003]传统卷绕式电芯(即电极组件)采用全连续涂覆设计，正负极片与隔离膜紧密层叠；循环过程中，活性物质层反复膨胀收缩产生巨大层间应力，该应力作用下，可能导致界面分层，进而活性物质层与集流体结合力衰减，内阻攀升，甚至卷芯(即电芯)变形，内圈极片褶皱断裂，外圈空隙塌陷引发短路，为缓解膨胀应力，行业通常采用增厚隔离膜或降低压实密度，但对电池能量密度的降低较为明显
[0022]1.本实用新型采用梯度化应力释放机制，一级缓冲设置为压花区凸台结构，通过弹性变形吸收活性层主要膨胀力；二级缓冲设置为未涂覆区，通过未涂覆区的空隙进一步容纳剩余膨胀量，避免层间挤压。
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Figure CN224732745U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of electrode assembly production technology, specifically to electrode assemblies and battery cells. Background Technology
[0002] As a core component of new energy vehicles and energy storage systems, the cycle life and safety of lithium-ion batteries are highly dependent on the stability of the electrode assembly structure. During battery charging and discharging, the volume expansion effect of active materials (especially with the application of high-nickel cathodes and silicon-carbon anodes) has become a key bottleneck restricting the improvement of battery performance.
[0003] Traditional wound cells (i.e., electrode assemblies) employ a fully continuous coating design, with positive and negative electrode sheets and separators tightly stacked. During cycling, the active material layer repeatedly expands and contracts, generating enormous interlayer stress. Under this stress, interface delamination may occur, leading to a decrease in the bonding force between the active material layer and the current collector, an increase in internal resistance, and even deformation of the core (i.e., the cell). The inner electrode sheets may wrinkle and break, and the outer gaps may collapse, causing a short circuit. To alleviate the expansion stress, the industry typically uses thicker separators or reduced compaction density, but this significantly reduces the battery's energy density.
[0004] Existing technologies for solving expansion stress can be mainly divided into two categories. The first is to reduce the expansion of active particles at the material level. This is generally achieved by using doping technology, carbon coating, etc., to directly weaken the stress source from the source, or by using binders to improve the overall integrity of the particles, thereby making their internal stress uniform.
[0005] Another approach involves using a stress frame or similar structure, pre-tightening the electrode assembly with a stainless steel shell or high-strength steel strip to control expansion within the frame and convert the internal expansion stress into circumferential tensile stress in the shell. Alternatively, an air bladder can be pre-installed inside the aluminum-plastic film shell, causing the electrode to bulge towards the air bladder when it expands. Some soft-pack module solutions also employ expansion constraint pads, placing aramid fibers between the cells to absorb the thickness increase.
[0006] However, improvements at the material level must also consider conductivity. Improvements in the structural framework mainly focus on mechanically suppressing expansion after the cell expands, making it difficult to directly control the expansion of the cell. At the same time, there is currently little research on the expansion suppression of electrode components. Therefore, how to design an electrode component and a single battery cell that can achieve gradient stress dispersion and thus control the expansion during the lithium-ion exchange process has become an urgent problem to be solved. Utility Model Content
[0007] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, one objective of this invention is to provide an electrode assembly designed to solve the expansion problem during lithium-ion exchange through gradient-transition stress dispersion.
[0008] This utility model further proposes a battery cell.
[0009] The electrode assembly according to the first aspect of this utility model includes:
[0010] The electrode assembly comprises a positive electrode sheet, a separator, and a negative electrode sheet, wherein the positive electrode sheet, the separator, and the negative electrode sheet are wound together to form the electrode assembly. The positive electrode sheet includes a positive current collector and a positive active material layer. Along the thickness direction of the positive current collector, both side surfaces of the positive current collector are coated with the positive active material layer. The side surfaces of the positive current collector have uncoated areas and multiple coated areas. The multiple coated areas are arranged sequentially along the length direction of the positive electrode sheet, and there is an uncoated area between at least two adjacent coated areas. The coated areas are coated with the positive active material layer.
[0011] According to the electrode assembly of the first aspect of this utility model, after the positive electrode sheet, the separator and the negative electrode sheet are wound to form the electrode assembly, the remaining expansion amount is accommodated through the gap in the uncoated area, so as to avoid the interlayer compression of the electrode assembly, and can effectively improve the problem of stress concentration of the inner winding curvature.
[0012] In some examples of this utility model, the positive electrode sheet has multiple embossed areas, which are arranged sequentially along the length of the positive electrode sheet. The multiple coating areas and the multiple embossed areas correspond one-to-one, and each embossed area forms multiple first protrusion structures protruding toward one side of the positive electrode sheet.
[0013] In some examples of this utility model, the plurality of coating areas include: a first coating area along the length direction of the positive electrode sheet, the positive electrode sheet having a winding start end, the first coating area being located between the uncoated area and the winding start end, and the plurality of embossing areas including a first embossing area corresponding to the first coating area, the first embossing area being spaced apart from the corresponding ends of the first coating area at both ends along the length direction of the positive electrode sheet.
[0014] In some examples of this utility model, the distance between the two ends of the first embossed area and the corresponding ends of the first coated area is L1, which satisfies the relationship: 5mm≤L1≤20mm.
[0015] In some examples of this utility model, the plurality of coating areas further include: a second coating area along the length direction of the positive electrode sheet, the second coating area being located on the side of the first coating area away from the winding start end, and an uncoated area between the second coating area and the first coating area; the plurality of embossing areas include a second embossing area corresponding to the second coating area, the end of the second embossing area near the first coating area along the length direction of the positive electrode sheet being spaced apart from the corresponding end of the second coating area.
[0016] In some examples of this invention, the end of the second embossed region away from the first coated region along the length direction of the positive electrode sheet is aligned with the corresponding end of the second coated region.
[0017] In some examples of this utility model, the distance between the end of the second embossed area near the first coated area along the length direction of the positive electrode sheet and the corresponding end of the second coated area is L2, which satisfies the relationship: 5mm≤L2≤20mm.
[0018] In some examples of this utility model, the length dimension of the uncoated area along the length direction of the positive electrode sheet is D, which satisfies the relationship: 8mm≤D≤150mm.
[0019] In some examples of this utility model, the negative electrode sheet has a third embossed area, which extends along the length direction of the negative electrode sheet. Along the length direction of the negative electrode sheet, one end of the third embossed area is spaced apart from the corresponding end of the negative electrode sheet, and the other end of the third embossed area is aligned with the corresponding end of the negative electrode sheet. The third embossed area forms a plurality of second protrusion structures protruding toward one side of the negative electrode sheet.
[0020] The battery cell according to the second aspect of this utility model includes the electrode assembly described above.
[0021] The beneficial effects of this utility model are as follows:
[0022] 1. This utility model adopts a gradient stress release mechanism. The first-level buffer is set as a raised structure in the embossed area, which absorbs the main expansion force of the active layer through elastic deformation. The second-level buffer is set as an uncoated area, which further accommodates the remaining expansion through the gaps in the uncoated area, thus avoiding interlayer compression.
[0023] 2. This utility model solves the problem of edge stress concentration and prevents sudden thickness changes by maintaining a gap between the boundary of the embossed area and the coated / uncoated area. At the same time, the opening at the starting end avoids tearing at small radius bends; the opening at the adjacent end of the uncoated area prevents secondary stress concentration.
[0024] 3. The present invention features an aligned end and a spaced end design in the negative electrode embossing area. The aligned end provides dense lithium deposition sites (pit structure); the spaced end forms a flat welding area, ensuring the reliability of the tab connection and comprehensively improving the stability of the negative electrode.
[0025] 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
[0026] The above and / or additional aspects and advantages of this utility model will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:
[0027] Figure 1 This is a schematic diagram of the structure of the positive electrode sheet provided in the embodiments of this application;
[0028] Figure 2 This is a schematic diagram of the first boss structure provided in an embodiment of this application;
[0029] Figure 3 This is a schematic diagram of the structure of the negative electrode sheet provided in the embodiments of this application;
[0030] Figure 4 This is a schematic diagram of the structure of the electrode assembly provided in an embodiment of this application.
[0031] Figure label:
[0032] 1-Positive electrode sheet, 101-Uncoated area, 102-First boss structure, 103-First coated area, 104-First embossed area, 105-Second coated area, 106-Second embossed area, 107-Positive current collector, 108-Positive active material layer, 109-Wound start end;
[0033] 2-Separation membrane;
[0034] 3-Negative electrode sheet, 301-Third embossed area, 302-Second boss structure. Detailed Implementation
[0035] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present utility model. In addition, it should be understood that the specific embodiments described herein are only for illustration and explanation of the present utility model and are not intended to limit the present utility model. In the present utility model, unless otherwise stated, directional terms such as "upper" and "lower" generally refer to the upper and lower positions of the device in actual use or operation, specifically the drawing directions in the accompanying drawings; while "inner" and "outer" refer to the outline of the device.
[0036] Please see Figure 1-4 This application provides an electrode assembly, including: a positive electrode 1, a separator 2, and a negative electrode 3. The positive electrode 1, separator 2, and negative electrode 3 are wound to form the electrode assembly. The positive electrode 1 includes: a positive current collector 107 and a positive active material layer 108. Along the thickness direction of the positive current collector 107, both side surfaces of the positive current collector 107 are coated with the positive active material layer 108. The side surfaces of the positive current collector 107 have uncoated areas 101 and multiple coated areas. The multiple coated areas are arranged sequentially along the length direction of the positive electrode 1, and there is an uncoated area 101 between at least two adjacent coated areas. The coated areas are coated with the positive active material layer 108.
[0037] It should be noted that the uncoated area 101 of the positive electrode current collector 107 is set as a blank foil, that is, a thin aluminum sheet with a smaller thickness relative to the coated area. When the positive electrode current collector 107 with blank foil is made into a wound electrode assembly, if a section of uncoated bare aluminum foil is set in the center of the positive electrode sheet 1, a significant step difference is formed in the thickness direction of the area, leaving a gap between adjacent wound layers. During battery cycling, the active material undergoes volume expansion due to lithium ion insertion / extraction. The reserved gap first absorbs the thickness increase caused by the expansion, reducing the interlayer extrusion stress of the electrode assembly. The aluminum foil undergoes local bending deformation at the gap, further dispersing the stress concentration. After the influence of the main stress is reduced, the shear slip effect of the remaining stress on the interface between the active material layer and the current collector is reduced, and the increase in interface impedance is slowed down.
[0038] As an example rather than a limitation on the scope of protection, if an aluminum foil of 12-15 μm thickness is used as the current collector, and the total dry thickness of the coated area after double-sided coating of the positive electrode 1 is between 145-175 μm (including the aluminum foil), and the separator is 275-90 μm thick, and the negative electrode 3 uses a lithium metal negative electrode with a total thickness controlled between 20-50 μm, and the length of the positive electrode 1 is set at 1500 mm, and a certain length of uncoated area 101 is set at the middle position of the positive electrode 1, and during the winding process, the radius of the core is added to the total thickness of the electrode assembly for each turn of winding around the shaft, generally around 20 turns, and the uncoated area 101 participates in the winding process. At this time, the core... With a single-turn circumference of approximately 55–65 mm, under these conditions, the initial uncoated area 101 can be set to 8–13 mm, which is 15%–23% of the full-turn circumference. This controls the ratio of the stress-dispersing area to the ion-exchange-participating area. Research has shown that directly incorporating the uncoated area 101 during the initial few turns of winding generally results in a worse stress control effect than adding the uncoated area 101 after winding a certain number of turns. In the initial few turns of winding, the diameter of the winding needle is relatively small, and both the aluminum foil and the separator 2 are under high tension. Even if the uncoated area 101 is incorporated, the aluminum foil cannot produce sufficient local bending, and the resulting gaps are relatively small, absorbing less expansion and resulting in a poor effect.
[0039] In some embodiments, the positive electrode 1 has a plurality of embossed regions arranged sequentially along the length of the positive electrode 1, and the plurality of coating regions correspond one-to-one with the plurality of embossed regions. Each embossed region forms a plurality of first boss structures 102 protruding toward one side of the positive electrode 1.
[0040] It should be emphasized that the first protrusion structure 102 formed by embossing has a more macroscopic structure compared with the reserved gap formed by the uncoated area 101. The expansion during the lithium-ion exchange process can be absorbed in the unidirectional protrusion of the first protrusion structure 102, while the protrusion structure on the positive and / or negative electrode still has surface contact with the separator 2 at both ends. In this area, the expansion during the lithium-ion exchange process is conducted sequentially and dispersed step by step by the protrusion structure of the positive and / or negative electrode and the reserved gap of the uncoated area 101.
[0041] It should be noted that by using the relatively macroscopic first protrusion structure 102 and the relatively microscopic reserved gap to process lithium exchange expansion, stress can be treated in a gradient manner to avoid stress concentration at local sites. The first protrusion structure 102 transforms the local expansion of the active layer into elastic compression or plastic deformation of the protrusion, and the initial stress is reduced. The reserved gap in the uncoated area 101 then absorbs the remaining thickness increment, completing the secondary unloading.
[0042] In some embodiments, such as Figure 1As shown, the multiple coating areas include: a first coating area 103 along the length direction of the positive electrode 1, the positive electrode 1 having a winding start end 109, the first coating area 103 being located between the uncoated area 101 and the winding start end 109, and multiple embossing areas including a first embossing area 104 corresponding to the first coating area 103, the first embossing area 104 being spaced apart from the corresponding ends of the first coating area 103 at both ends along the length direction of the positive electrode 1.
[0043] Specifically, during the actual winding process, the tension at the starting end 109 of the winding core is the greatest, and the starting end 109 is also the area with the smallest bending radius. Generally, the embossing process is carried out after the starting end 109 of the winding is spaced a certain distance along the length direction. Otherwise, if the embossing protrusion is close to the starting end 109 of the winding core, the sudden change in thickness at the edge will cause stress concentration at the bending point. By reserving a embossing clearance area, the stress can be transferred through the planar area first and then enter the protrusion area, reducing the risk of tearing of the positive electrode sheet 1.
[0044] In some embodiments, the distance between the two ends of the first embossed area 104 and the corresponding ends of the first coated area 103 is L1, satisfying the relationship: 5mm≤L1≤20mm;
[0045] Specifically, L1 can be a value such as 5mm, 6mm, 8mm, 10mm, 12mm, 16mm, 18mm, 20mm, etc. Controlling it to the lower limit of 5mm can ensure that even if multiple alignment tolerances of ±1 to 2mm occur with the same type of mechanical error, interference between the embossed protrusion and the cut edge of the positive electrode 1 is prevented.
[0046] In some embodiments, such as Figure 1 As shown, the multiple coating areas also include: a second coating area 105, which is located on the side of the first coating area 103 away from the winding start end 109 along the length direction of the positive electrode sheet 1, and there is an uncoated area 101 between the second coating area 105 and the first coating area 103; the multiple embossing areas include a second embossing area 106 corresponding to the second coating area 105, and the end of the second embossing area 106 near the first coating area 103 along the length direction of the positive electrode sheet 1 is spaced apart from the corresponding end of the second coating area 105.
[0047] It should be noted that an uncoated area 101 is fixedly provided between the first coated area 103 and the second coated area 105. The electrode thickness is reduced at this point, and it serves as a stress relief zone in stress transmission. If the second embossed area 106 is close to the end of the uncoated area 101, the embossed protrusion will form a new thickness change at the edge of the uncoated area 101, which will block the stress transmission and release while causing the shear stress to re-concentrate, thus weakening the buffering effect of the uncoated area 101.
[0048] It should be emphasized that the port where the uncoated area 101 is adjacent to the coated area can be regarded as the edge area relative to both the uncoated area 101 and the coated area. During the embossing process, if the embossing protrusion is close to the edge area, stress concentration is likely to occur due to the large thickness change in the edge area, which will affect the core performance. Therefore, by separating the end of the second embossing area 106 along the length direction of the positive electrode sheet 1 from the end of the first coated area 103 and the corresponding end of the second coated area 105, the risk of stress concentration during the embossing process is reduced, which is beneficial to improving the core performance.
[0049] In some embodiments, the end of the second embossed region 106 that is away from the first coated region 103 along the length direction of the positive electrode sheet 1 is aligned with the corresponding end of the second coated region 105.
[0050] It should be noted that the embossing protrusions of the second embossing region 106 form a structure on the end face to prevent the interface peeling of the positive electrode 1 edge during winding or cyclic expansion.
[0051] In some embodiments, the distance between the end of the second embossed region 106 near the first coating region 103 along the length direction of the positive electrode sheet 1 and the corresponding end of the second coating region 105 is L2, satisfying the relationship: 5mm≤L2≤20mm;
[0052] It should be noted that L2 can be 5mm, 6mm, 8mm, 10mm, 12mm, 16mm, 18mm, 20mm, etc. The side of the second coating area 105 closest to the first coating area 103 is the port of the uncoated area 101. If the embossing boss of the second embossing area 106 is close to this end, the stress will be concentrated twice in a very narrow area. A 5-20mm plane transition is reserved so that the stress can be unloaded through the uncoated area 101 first and then enter the second embossing area 106, avoiding the risk of stress bridging.
[0053] In some embodiments, the length dimension of the uncoated area 101 along the length direction of the positive electrode 1 is D, which satisfies the relationship: 8mm≤D≤150mm;
[0054] For example, D can be 8mm, 10mm, 12mm, 16mm, 18mm, 20mm, 145mm, 150mm, etc., still using 12-15μm thick aluminum foil as the current collector, the total dry thickness of the coated area after double-sided coating of the positive electrode 1 is between 145-175μm (including aluminum foil), the separator 2 is 75-90μm, the negative electrode 3 uses lithium metal negative electrode and controls the total thickness to be between 20-50μm, and the length of the positive electrode 1 is according to... Calculated at 1500mm; the following layout can be adopted: The first uncoated area 101, with a controlled length of 13mm, is set at 750mm of electrode winding, corresponding to 20 winding turns. When the circumference of the turn is 58mm, the uncoated area 101 accounts for 22.4% of the total length of the turn. The second uncoated area 101, with a controlled length of 14mm, is set at 890mm of electrode winding, corresponding to 22 winding turns. When the circumference of the turn is 62mm, the uncoated area 101 accounts for 22.4% of the total length of the turn. The total length ratio is 22.5%. The third uncoated area 101 has a controlled length of 15mm and is located at 1050mm of the electrode winding, corresponding to 24 winding turns. When the circumference of the turn is 66mm, the uncoated area 101 accounts for 22.7% of the total length of the turn. The fourth uncoated area 101 has a controlled length of 16mm and is located at 1200mm of the electrode winding, corresponding to 26 winding turns. When the circumference of the turn is 71mm, the uncoated area 101 accounts for 22.7% of the total length of the turn. 22.5%, the fifth uncoated area 101 has a controlled length of 17mm and is located at 1350mm of the electrode winding, corresponding to 28 winding turns. When the circumference of the turn is 75mm, the uncoated area 101 accounts for 22.6% of the total length of the turn. The sixth uncoated area 101 has a controlled length of 18mm and is located at 1450mm of the electrode winding, corresponding to 29 winding turns. When the circumference of the turn is 78mm, the uncoated area 101 accounts for 23.1% of the total length of the turn.
[0055] It should be noted that, by adopting the above scheme, starting from the 20th ring, uncoated areas 101 can be set in the 22nd, 24th, 26th, 28th and 29th rings, evenly distributed between adjacent rings, controlling the ratio of ion exchange area to stress release area. Specifically, the position of uncoated area 101 in this ring can be adjusted, that is, the corresponding position of uncoated area 101 in the electrode length direction can be changed so that the reserved gaps in adjacent rings have different orientations, thus fully realizing the segmented stress dispersion effect.
[0056] In some embodiments, such as Figure 3 As shown, the negative electrode 3 has a third embossed region 301, which extends along the length direction of the negative electrode 3. Along the length direction of the negative electrode 3, one end of the third embossed region 301 is spaced apart from the corresponding end of the negative electrode 3, and the other end of the third embossed region 301 is aligned with the corresponding end of the negative electrode 3. The third embossed region 301 forms a plurality of second boss structures 302 protruding toward one side of the negative electrode 3.
[0057] It should be noted that the third embossed region 301 on the negative electrode 3 is configured with one end aligned and the other end having a reserved gap. The end with the reserved gap is set as a continuous plane with a consistent thickness, which can be directly used as the welding area for the negative electrode tab. The aligned side is formed with as many embossed structures as possible, thereby providing more lithium deposition sites on the surface of the negative electrode 3, allowing lithium to be deposited in the pits created by the embossing, thus reducing the thickness of the negative electrode 3, reducing the stress caused by thickness changes, and consequently reducing the expansion rate of the entire electrode assembly.
[0058] The electrode assembly of this application, by setting embossed areas on the positive electrode 1 and the negative electrode 3, can precisely control the electrode assembly gap. This assembly gap serves as a directional release channel for expansion stress, effectively suppressing the plastic deformation of the electrode-separator 2 interface during cycling, reducing contact loss between the active material layer and the current collector, and providing sufficient space for the expansion of the lithium-ion battery. This protects the internal structure of the lithium-ion battery from damage by expansion stress and can extend the battery's cycle life. Furthermore, by setting an uncoated area 101 on the positive electrode 1, the area corresponding to the uncoated area 101 after the electrode assembly is wound can provide a buffer space for the expansion of the active material. The electrode does not expand in this area, which is conducive to the release of stress during the expansion of the electrode assembly, thereby mitigating the adverse effects caused by the expansion of the electrode assembly.
[0059] This application also provides a battery cell, including the electrode assembly described in the above embodiments. By incorporating the electrode assembly into the battery cell, the working performance of the battery cell can be improved, which is beneficial to enhancing the working reliability of the battery cell.
[0060] The embodiments of this utility model have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this utility model. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this utility model. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this utility model. Therefore, the content of this specification should not be construed as a limitation of this utility model.
Claims
1. An electrode assembly, characterized by, include: The electrode assembly comprises a positive electrode sheet, a separator, and a negative electrode sheet, wherein the positive electrode sheet, the separator, and the negative electrode sheet are wound together to form the electrode assembly. The positive electrode sheet includes a positive current collector and a positive active material layer. Along the thickness direction of the positive current collector, both side surfaces of the positive current collector are coated with the positive active material layer. The side surfaces of the positive current collector have uncoated areas and multiple coated areas. The multiple coated areas are arranged sequentially along the length direction of the positive electrode sheet, and there is an uncoated area between at least two adjacent coated areas. The coated areas are coated with the positive active material layer.
2. The electrode assembly of claim 1, wherein, The positive electrode sheet has multiple embossed areas, which are arranged sequentially along the length of the positive electrode sheet. The multiple coating areas and the multiple embossed areas correspond one-to-one. Each embossed area forms multiple first protrusion structures that protrude toward one side of the positive electrode sheet.
3. The electrode assembly of claim 2, wherein, The plurality of coating areas include: a first coating area along the length direction of the positive electrode sheet, the positive electrode sheet having a winding start end, the first coating area being located between the uncoated area and the winding start end; and the plurality of embossing areas including a first embossing area corresponding to the first coating area, the first embossing area being spaced apart from the corresponding ends of the first coating area at both ends along the length direction of the positive electrode sheet.
4. The electrode assembly of claim 3, wherein, The distance between the two ends of the first embossed area and the corresponding ends of the first coated area is L1, which satisfies the relationship: 5mm≤L1≤20mm.
5. The electrode assembly of claim 3, wherein, The plurality of coating areas further include: a second coating area along the length direction of the positive electrode sheet, the second coating area being located on the side of the first coating area away from the winding start end, and an uncoated area between the second coating area and the first coating area; the plurality of embossing areas include a second embossing area corresponding to the second coating area, the end of the second embossing area near the first coating area along the length direction of the positive electrode sheet being spaced apart from the corresponding end of the second coating area.
6. The electrode assembly of claim 5, wherein, The end of the second embossed area that is away from the first coated area along the length of the positive electrode sheet is aligned with the corresponding end of the second coated area.
7. The electrode assembly of claim 5, wherein, The distance between the end of the second embossed area near the first coating area and the corresponding end of the second coating area along the length of the positive electrode sheet is L2, which satisfies the relationship: 5mm≤L2≤20mm.
8. The electrode assembly of claim 1, wherein, Along the length of the positive electrode sheet, the length of the uncoated area is D, which satisfies the relationship: 8mm≤D≤150mm.
9. The electrode assembly of any one of claims 1-8, wherein, The negative electrode sheet has a third embossed area that extends along the length of the negative electrode sheet. Along the length of the negative electrode sheet, one end of the third embossed area is spaced apart from the corresponding end of the negative electrode sheet, and the other end of the third embossed area is aligned with the corresponding end of the negative electrode sheet. The third embossed area forms a plurality of second protrusion structures that protrude toward one side of the negative electrode sheet.
10. A battery cell characterized by, Includes the electrode assembly according to any one of claims 1-9.