Electrode assembly, battery, and electric device

Abstract

An electrode assembly, a battery, and an electric device. The electrode assembly is of a winding structure and comprises a first electrode sheet and a second electrode sheet, and a second winding end section of the second electrode sheet is away from a winding center of the winding structure relative to a first winding end section of the first electrode sheet; the second winding end section comprises a second winding end; the electrode assembly comprises a first winding region, the first winding region is a region covered by a ray from the winding center to the second winding end that rotates a radian of π / 3 around the winding center in the winding direction, and a first support member is provided in the first winding region. The first support member is provided in the first winding region, so that when the electrode assembly expands to abut against the side wall of a housing, the first support member can provide support for the first winding region. In a further cycle process, the expansion and deformation of the electrode assembly in the first winding region are inhibited, thereby reducing the risk of the outer electrode sheet of the first winding region breaking due to expansion and pulling, and prolonging the service life of the battery.

Description

An electrode assembly, a battery, and an electrical device. Technical Field

[0001] This application relates to the field of battery technology, and in particular to an electrode assembly, a battery, and an electrical device. Background Technology

[0002] Cylindrical batteries are widely used in electric vehicles, energy storage, and power tools due to their ease of manufacturing and high safety. By reducing the gap between the core and the casing, the energy density of the battery can be increased. At the same time, under drop and vibration conditions, the movement of the core within the casing can be suppressed, preventing damage to other components, such as the current collector, thereby improving the safety and reliability of the battery.

[0003] Summary of the Invention

[0004] However, the inventors of this application have discovered that, due to its unique spiral winding structure, the outer electrode sheet of the core is prone to breakage during cyclic use, thus affecting the battery's lifespan. This is because, under cyclic conditions, the active material in the electrode sheet undergoes volume expansion due to lithium insertion / extraction, which stretches the current collector. As the core expands cyclically, the tail section of the core preferentially abuts against the side wall of the casing to form a support point, limiting the further extension of the current collector at the tail section. During further cyclic expansion, the core tends to expand towards the gap at the spiral tail end, causing the electrode sheet at the spiral tail end to be subjected to more severe stretching and extension, leading to breakage and affecting the normal use of the battery. In view of the above technical problems, this application provides an electrode assembly, a battery, and an electrical device to reduce the risk of electrode sheet breakage during cyclic use and improve battery lifespan.

[0005] According to a first aspect of this application, this application provides an electrode assembly, the electrode assembly being a wound structure, the electrode assembly including a first electrode sheet and a second electrode sheet, the first electrode sheet including a first wound tail section, the second electrode sheet including a second wound tail section, the second wound tail section being farther away from the winding center of the wound structure relative to the first wound tail section; the second wound tail section including a second wound end; the electrode assembly including a first winding region, the first winding region being the area covered by a ray from the winding center to the second wound end rotating π / 3 radians along the winding direction with the winding center as the center, wherein: the electrode assembly further includes a first support member, at least a portion of the first support member being disposed in the first winding region; the thickness of the first support member portion disposed in the first winding region is T1; the thickness of the first wound tail section is t1, the thickness of the second wound tail section is t2; satisfying: T1≤T, where T=t1+t2. This application reduces or eliminates the gap difference between the first winding area and the second winding end section relative to the housing sidewall by setting a first support member in the first winding area. When the electrode assembly expands to abut against the housing sidewall, the first support member can provide support for the first winding area. In further cycling, it suppresses the expansion deformation of the electrode assembly in the first winding area, thereby reducing the risk of the outer electrode sheet of the first winding area breaking due to expansion and stretching, and improving the battery life.

[0006] In any one or more alternative embodiments, 0.7T≤T1≤T. Thus, adjusting T1 within the range of 0.7TT allows the first support member to better fill the gap difference between the first winding area and the second winding end section relative to the sidewall of the housing, thereby providing better support for the first winding area, further reducing the risk of the outer electrode sheet of the first winding area breaking due to expansion and stretching, and improving the battery's service life.

[0007] In any one or more alternative embodiments, the electrode assembly further includes: a second winding region, the second winding region being the region remaining after removing the first winding region from the region covered by a ray from the winding center to the second winding end rotating 2π / 3 radians along the winding direction.

[0008] In any one or more optional embodiments, the first support member further includes a second region disposed in the second winding area, the thickness of the second region being T2, satisfying: 0.5T≤T2≤0.7T.

[0009] In any one or more optional embodiments, the electrode assembly further includes a second support member, at least a portion of which is disposed in the second winding region; the thickness of the portion of the second support member disposed in the second winding region is T2, satisfying: 0.5T≤T2≤0.7T.

[0010] Thus, by setting a second region or a second support member in the second winding area, the gap difference between the second winding area and the second winding end section relative to the housing sidewall is reduced or eliminated. When the electrode assembly expands to abut against the housing sidewall, the second region or the second support member can provide support for the second winding area. In further cycling, the expansion deformation of the electrode assembly in the second winding area is suppressed, thereby reducing the risk of the outer electrode sheet of the second winding area breaking due to expansion and stretching, and improving the battery life.

[0011] In any one or more alternative embodiments, the electrode assembly further includes a third winding region, which is the region remaining after removing the first winding region and the second winding region from the region covered by a ray from the winding center to the second winding end rotating π radians along the winding direction.

[0012] In any one or more optional embodiments, the first support member further includes a third region disposed in the third winding area, the thickness of the third region being T3, satisfying: 0.3T≤T3≤0.5T.

[0013] In any one or more optional embodiments, the electrode assembly further includes a third support member, at least a portion of which is disposed in the third winding region; the thickness of the portion of the third support member disposed in the third winding region is T3, satisfying: 0.3T≤T3≤0.5T.

[0014] Thus, by setting the third region of the first support member or the third support member in the third winding area, the gap difference between the third winding area and the second winding end section relative to the housing sidewall is reduced or eliminated. When the electrode assembly expands to abut against the housing sidewall, the third region of the first support member or the third support member can provide support for the third winding area. In further cycling, the expansion deformation of the electrode assembly in the third winding area is suppressed, thereby reducing the risk of the outer electrode sheet of the third winding area breaking due to expansion and stretching, and improving the battery life.

[0015] In any one or more alternative embodiments, the coverage arc of the first support portion disposed in the first winding area along the winding direction is w1, satisfying: π / 6 ≤ w1 ≤ π / 3. Thus, the first support can better provide support for the first winding area, suppressing the expansion and deformation of the electrode assembly in the first winding area, further reducing the risk of the outer electrode sheet of the first winding area breaking due to expansion and stretching, and improving the battery's lifespan.

[0016] In any one or more alternative embodiments, the coverage arc of the second region along the winding direction is w2, satisfying: π / 6≤w2≤π / 3.

[0017] In any one or more alternative embodiments, the coverage arc of the second support portion disposed in the second winding area along the winding direction is w2, satisfying: π / 6≤w2≤π / 3.

[0018] In this way, the second region of the first support member or the second support member can better support the second winding area, suppress the expansion and deformation of the electrode assembly in the second winding area, further reduce the risk of the outer electrode sheet of the second winding area breaking due to expansion and stretching, and improve the service life of the battery.

[0019] In any one or more alternative embodiments, the coverage arc of the third region along the winding direction is w3, satisfying: π / 6≤w3≤π / 3.

[0020] In any one or more alternative embodiments, the coverage arc of the third support portion disposed in the third winding area along the winding direction is w3, satisfying: π / 6≤w3≤π / 3.

[0021] In this way, the third region of the first support member or the third support member can better support the third winding area, suppress the expansion and deformation of the electrode assembly in the third winding area, further reduce the risk of the outer electrode sheet of the third winding area breaking due to expansion and stretching, and improve the service life of the battery.

[0022] In any one or more alternative embodiments, the first support member includes at least one of a first tape or a first coating.

[0023] In any one or more alternative embodiments, the second support member includes at least one of a second tape or a second coating.

[0024] In any one or more alternative embodiments, the third support member includes at least one of a third tape or a third coating.

[0025] In any one or more alternative embodiments, the first tape is adhered to the outermost surface of the first winding area or to the surface of the outermost second electrode sheet of the first winding area away from the winding center.

[0026] In any one or more alternative embodiments, the outermost second electrode sheet located in the first winding area does not have a second active material layer on the side surface facing away from the winding center, and the first coating is disposed on the surface of the outermost second electrode sheet located in the first winding area facing away from the winding center.

[0027] In any one or more alternative embodiments, the first coating comprises at least one of a polymer or an inorganic material.

[0028] In any one or more alternative embodiments, the second tape is adhered to the outermost surface of the second winding area or to the surface of the outermost second electrode sheet of the second winding area opposite to the winding center.

[0029] In any one or more alternative embodiments, the outermost second electrode sheet in the second winding area is not provided with a second active material layer on the side surface opposite to the winding center, and the second coating is provided on the surface of the outermost second electrode sheet in the second winding area opposite to the winding center.

[0030] In any one or more alternative embodiments, the second coating comprises at least one of a polymer or an inorganic material.

[0031] In any one or more alternative embodiments, the third tape is adhered to the outermost surface of the third winding area or to the surface of the outermost second electrode sheet of the third winding area opposite to the winding center.

[0032] In any one or more alternative embodiments, the outermost second electrode sheet in the third winding region is not provided with a second active material layer on the side surface facing away from the winding center, and the third coating is provided on the surface of the outermost second electrode sheet in the third winding region facing away from the winding center.

[0033] In any one or more alternative embodiments, the third coating comprises at least one of a polymer or an inorganic material.

[0034] According to a second aspect of this application, this application also provides a battery including a housing and an electrode assembly as described in any of the above embodiments, the housing being cylindrical and the electrode assembly being housed within the housing.

[0035] According to a third aspect of this application, this application also provides an electrical device including the aforementioned battery. Attached Figure Description

[0036] One or more embodiments are illustrated by way of example with reference to the accompanying drawings, in which elements having the same reference numerals are designated as similar elements, and unless otherwise stated, the figures in the drawings are not intended to be limited by scale.

[0037] Figure 1 is a schematic diagram of the battery structure in some embodiments of this application;

[0038] Figure 2 is a schematic diagram of the structure of the electrode assembly in some embodiments of this application;

[0039] Figure 3 is a schematic diagram of the electrode winding state in some embodiments of this application;

[0040] Figure 4 is a view of the electrode winding state in Figure 3 along the second direction Y;

[0041] Figure 5 is an enlarged view of point A in Figure 4;

[0042] Figure 6 is a schematic diagram of the battery structure in some embodiments of this application;

[0043] Figure 7 is a schematic diagram of the battery structure in some other embodiments of this application;

[0044] Figure 8 is a schematic diagram of the battery structure in some other embodiments of this application;

[0045] Figure 9 is a schematic diagram of the battery structure in some other embodiments of this application;

[0046] Figure 10 is a structural schematic diagram of the first support member in Figure 9;

[0047] Figure 11 is a schematic diagram of the battery structure in some embodiments of this application;

[0048] Figure 12 is a structural schematic diagram of the first support member in Figure 11;

[0049] Figure 13 is a schematic diagram of the battery structure in some other embodiments of this application;

[0050] Figure 14 is a schematic diagram of the battery structure in some other embodiments of this application;

[0051] Meaning of related reference numerals: Electrode assembly 100, first winding area 101, first winding area 102, first winding area 103; Housing 200; First electrode 1, first winding end section 10; Second electrode 2, second winding end section 20, second winding end 21; First support member 31, first region 311, second region 312, third region 313, second support member 32, third support member 33; Diaphragm 4. Detailed Implementation

[0052] To facilitate understanding of this application, a more detailed description is provided below with reference to the accompanying drawings and specific embodiments. Unless otherwise specified, the following embodiments and features can be combined with each other. It should be noted that when an element is described as being "fixed to" another element, it can be directly on the other element, or one or more intermediate elements may exist between them. When an element is described as being "connected" to another element, it can be directly connected to the other element, or one or more intermediate elements may exist between them. The terms "vertical," "horizontal," "left," "right," and similar expressions used in this specification are for illustrative purposes only.

[0053] Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the scope of this application. The term "and / or" as used in this specification includes any and all combinations of one or more of the associated listed items.

[0054] One embodiment of this application discloses a battery, as shown in FIG1, including an electrode assembly 100 and a housing 200. The electrode assembly 100 is encapsulated within the housing 200, which is cylindrical in shape. As shown in FIG2-5, the electrode assembly 100 includes an electrode assembly wound around a center along a fixed winding direction. The electrode assembly includes a separator 4, a first electrode 1, a separator 4, and a second electrode 2 stacked sequentially. After winding, a separator 4 is provided between adjacent turns of the first electrode 1 and the second electrode 2 to prevent direct contact between them. One of the first electrode 1 and the second electrode 2 is a negative electrode, and the other is a positive electrode. For example, the first electrode 1 is a positive electrode, and the second electrode 2 is a negative electrode; or, the first electrode 1 is a negative electrode, and the second electrode 2 is a positive electrode. The first electrode 1 includes a first current collector and a first active material layer disposed on the surface of the first current collector; the second electrode 2 includes a second current collector and a second active material layer disposed on the surface of the second current collector.

[0055] As shown in Figures 3-5, the first electrode 1 includes a first winding termination section 10, and the second electrode 2 includes a second winding termination section 20. The first winding termination section 10 corresponds to the portion of the outermost ring of the first electrode 1 rotated 90° in the opposite direction of the winding direction from the winding center. The second winding termination section 20 corresponds to the portion of the outermost ring of the second electrode 2 rotated 90° in the opposite direction of the winding direction from the winding center. The second winding termination section 20 is located away from the winding center O of the winding structure relative to the first winding termination section 10; that is, the second electrode 2 in the same layer of the wound electrode assembly is located on the side of the first electrode 1 away from the winding center O. The second winding termination section 20 includes a second winding end 21, which is located at the end of the second winding termination section 20 along the winding direction. The first winding termination section 10 includes a first winding end (not shown), which is located at the end of the first winding termination section 10 along the winding direction. In some embodiments, the first electrode 1 is a positive electrode, the second electrode 2 is a negative electrode, and the second winding end 21 extends beyond the first winding end along the winding direction. In other embodiments, the first electrode 1 is a negative electrode, the second electrode 2 is a positive electrode, and the first winding end extends beyond the second winding end 21 along the winding direction. This ensures that the negative electrode active material layer completely covers the opposite positive electrode active material layer, reducing the risk of lithium plating during charging of the electrode assembly.

[0056] As shown in Figures 2 and 6, the electrode assembly 100 includes a first winding region 101, which is a fan-shaped area covered by rotating π / 3 radians (60°) along the winding direction with the winding center O as the center and the ray from the winding center O to the second winding end 21 as the radius. The electrode assembly 100 also includes a first support member 31, which is partially or entirely disposed within the first winding region 101.

[0057] The first support member 31 can be disposed on the outermost side of the wound electrode assembly, or it can be disposed on any layer between the winding center O and the outermost layer of the wound electrode assembly, for example, on the second electrode 2 inside the diaphragm 4 layer that extends beyond the first winding end section 10 and the second winding end section 20.

[0058] By providing a first support member 31 in the first winding area 101, the gap difference between the first winding area 101 and the second winding end section 20 relative to the side wall of the housing is reduced or eliminated. When the electrode assembly 100 expands to abut against the side wall of the housing 200, the first support member 31 can provide support for the first winding area 101. In further cycling, the expansion deformation of the electrode assembly 100 in the first winding area 101 is suppressed, thereby reducing the risk of the outer electrode sheet of the first winding area 101 breaking due to expansion and stretching, and improving the service life of the battery.

[0059] In some embodiments, the coverage arc of the portion of the first support member 31 disposed in the first winding area 101 along the winding direction is w1, that is, the coverage arc of the portion of the first support member 31 located in the first winding area 101 along the winding direction is w1, and satisfies: π / 6≤w1≤π / 3. Thus, the first support member 31 can better provide support for the first winding area 101, suppressing the expansion and deformation of the electrode assembly 100 in the first winding area 101, further reducing the risk of the outer electrode sheet of the first winding area 101 breaking due to expansion and stretching, and improving the battery's lifespan. In some embodiments, as shown in FIG6, the first support member 31 is located at the outermost layer of the first winding area 101.

[0060] Specifically, as shown in Figure 6, one end of the first support member 31 is positioned opposite to the second winding end 21, and the other end extends along the winding direction. The thickness of the portion of the first support member 31 located within the first winding area 101 is T1; the thickness of the first winding termination section 10 is t1, and the thickness of the second winding termination section 20 is t2; the relationship between T, T1, t1, and t2 satisfies: 0.7T ≤ T1 ≤ T, where T = t1 + t2. In the first winding area 101, the end adjacent to the second winding end 21 and the second winding termination section 20 have the largest gap difference (approximately T) relative to the sidewall of the housing 200, while the end of the first winding area 101 located away from the second winding end 21 along the winding direction has the smallest gap difference (approximately 0.7T) relative to the sidewall of the housing 200. By adjusting T1 within the range of 0.7TT, the first support member 31 can better fill the gap difference between the first winding area 101 and the second winding end section 20 relative to the side wall of the housing 200, thereby providing better support for the first winding area 101, reducing the risk of the outer electrode sheet of the first winding area 101 breaking due to expansion and stretching, and improving the service life of the battery.

[0061] In some embodiments, the thickness of the portion of the first support 31 within the first winding area 101 can be a fixed value. In other embodiments, since the gap difference between the first winding area 101 and the second winding end section 20 relative to the sidewall of the housing 200 starts from the second winding end 21 and gradually decreases along the electrode winding direction, the thickness of the portion of the first support 31 located in the first winding area 101 gradually decreases along the winding direction.

[0062] In some embodiments, as shown in Figures 7 and 8, the electrode assembly 100 further includes a second winding region 102. The second winding region 102 is the area remaining after removing the first winding region 101 from the area covered by rotating the ray from the winding center O to the second winding end 21 by 2π / 3 radians (120°) along the winding direction. That is, the second winding region 102 is the area covered by rotating the ray from the winding center O to the boundary of the first winding region 101 away from the second winding end 21 by π / 3 radians along the winding direction.

[0063] In some embodiments, as shown in FIG7, the first support member 31 includes a first region 311 located in the first winding region 101 and a second region 312 disposed in the second winding region 102. That is, the first support member 31 extends from the first winding region 101 to the second winding region 102 along the winding direction. The thickness of the second region 312 is T2, and the thickness of T2 satisfies 0.5T≤T2≤0.7T.

[0064] In some other embodiments, as shown in FIG8, the electrode assembly 100 further includes a second support member 32, which is at least partially disposed in the second winding area 102. The thickness of the portion of the second support member 32 disposed in the second winding area 102 is T2, and the thickness of T2 satisfies 0.5T≤T2≤0.7T.

[0065] In the second winding region 102, the largest gap difference (approximately 0.7T) exists between the boundary with the first winding region 101 and the second winding termination section 20 relative to the sidewall of the housing 200. Conversely, at the end of the second winding region 102 away from the first winding region 101 along the winding direction, the smallest gap difference (approximately 0.5T) exists between the second winding termination section 20 and the sidewall of the housing 200. Thus, by adjusting T2 within the range of 0.5T-0.7T, the second region 312 or the second support member 32 can better fill the gap difference between the second winding region 102 and the second winding termination section 20 relative to the sidewall of the housing 200, thereby providing better support for the second winding region 102, reducing the risk of the outer electrode sheet of the second winding region 102 breaking due to expansion and stretching, and improving the battery's lifespan.

[0066] Similarly, in some embodiments, as shown in FIG12, the thickness of the second region 312 can be a fixed value. In other embodiments, as shown in FIG10, the thickness of the second region 312 can also gradually decrease along the winding direction, so that the thickness variation of the second region 312 matches the gap difference between the second winding area 102 and the second winding tail section 20 relative to the sidewall of the housing 200, thereby achieving more sufficient filling of this gap difference. In some embodiments, the second support member 32 is located in a portion of the second winding area 102, and its thickness can be a fixed value. In other embodiments, the second support member 32 is located in a portion of the second winding area 102, and its thickness can gradually decrease along the winding direction.

[0067] In some embodiments, the coverage arc of the second region 312 along the winding direction is w2, and satisfies: π / 6 ≤ w2 ≤ π / 3. Thus, the second region 312 can better provide support for the second winding region 102, suppressing the expansion and deformation of the electrode assembly 100 in the second winding region 102, further reducing the risk of the outer electrode sheet of the second winding region 102 breaking due to expansion and stretching, and improving the battery's lifespan.

[0068] In some embodiments, the coverage arc of the portion of the second support member 32 disposed in the second winding region 102 along the winding direction is w2, that is, the coverage arc of the portion of the second support member 32 located in the second winding region 102 along the winding direction is w2, and satisfies: π / 6≤w2≤π / 3. Thus, the second support member 32 can better provide support for the second winding region 102, suppressing the expansion and deformation of the electrode assembly 100 in the second winding region 102, further reducing the risk of the outer electrode sheet of the second winding region 102 breaking due to expansion and stretching, and improving the battery's service life.

[0069] In some embodiments, as shown in Figures 9 and 13, the electrode assembly 100 further includes a third winding region 103. The third winding region 103 is the region remaining after removing the first winding region 101 and the second winding region 102 from the region covered by rotating the ray from the winding center O to the second winding end 21 along the winding direction by π radians (180°). That is, the third winding region 103 is the region covered by rotating the ray from the winding center O to the ray along the winding direction by π / 3 radians with the ray as the radius and the ray as the radius of the ray on the side of the second winding region 102 away from the first winding region 101.

[0070] In some embodiments, as shown in Figures 9 and 10, the first support member 31 further includes a third region 313 disposed in the third winding region 103. That is, the first support member 31 includes a first region 311 located in the first winding region 101, a second region 312 disposed in the second winding region 102, and a third region 313 extending into the third winding region 103. The thickness of the third region 313 is T3, and the thickness of T3 satisfies: 0.3T ≤ T3 ≤ 0.5T.

[0071] In some other embodiments, the electrode assembly 100 further includes a third support member 33, which is at least partially disposed in the third winding region 103. The portion of the third support member 33 disposed in the third winding region 103 has a thickness of T3, and the thickness of T3 satisfies 0.3T≤T3≤0.5T.

[0072] In the third winding region 103, the largest gap difference (approximately 0.5T) exists between the boundary with the second winding region 102 and the second winding termination section 20 relative to the sidewall of the housing 200. Conversely, in the third winding region 103, at the end away from the second winding region 102 along the winding direction, the smallest gap difference (approximately 0.3T) exists between the second winding termination section 20 and the sidewall of the housing 200. Thus, by adjusting T3 within the range of 0.3T-0.5T, the third region 313 or the third support member 33 can better fill the gap difference between the third winding region 103 and the second winding termination section 20 relative to the sidewall of the housing 200, thereby providing better support for the third winding region 103, reducing the risk of the outer electrode sheet of the third winding region 103 breaking due to expansion and stretching, and improving the battery's lifespan.

[0073] Similarly, in some embodiments, as shown in Figures 11 and 12, the thicknesses of the first region 311, the second region 312, and the third region 313 are fixed values, and their thicknesses decrease sequentially. In other embodiments, as shown in Figures 9 and 10, the thickness of the third region 313 gradually decreases along the winding direction, so that the thickness change of the third region 313 matches the gap difference between the third winding area 103 and the second winding tail section 20 relative to the sidewall of the housing 200, allowing the third region 313 to fill this gap difference more fully. In some embodiments, the third support member 33 is located in a portion of the third winding area 103, and its thickness can be a fixed value. In other embodiments, the thickness of the third support member 33 located in a portion of the third winding area 103 can gradually decrease along the winding direction.

[0074] In some embodiments, the coverage arc of the third region 313 along the winding direction is w3, and satisfies: π / 6 ≤ w3 ≤ π / 3. Thus, the third region 313 can better provide support for the third winding region 103, suppressing the expansion and deformation of the electrode assembly 100 in the third winding region 103, further reducing the risk of the outer electrode sheet of the third winding region 103 breaking due to expansion and stretching, and improving the battery's lifespan.

[0075] In some embodiments, the coverage arc of the portion of the third support member 33 located in the third winding region 103 along the winding direction is w3. That is, the coverage arc of the portion of the third support member 33 located in the third winding region 103 along the winding direction is w3, and satisfies: π / 6 ≤ w3 ≤ π / 3. Thus, the third support member 33 can better provide support for the third winding region 103, suppress the expansion and deformation of the electrode assembly 100 in the third winding region 103, further reduce the risk of the outer electrode sheet of the third winding region 103 breaking due to expansion and stretching, and improve the battery's service life.

[0076] In some embodiments, the specific structure of the electrode assembly 100 may also be as shown in FIG14. The first support member 31 includes a first region 311 located in the first winding region 101 and a second region 312 disposed in the second winding region 102. That is, the first support member 31 extends from the first winding region 101 along the winding direction to the second winding region 102. The difference is that the third winding region 103 is provided with a third support member 33.

[0077] In some embodiments, the first support member 31 includes a first adhesive tape, which is adhered to the outermost surface of the first winding area 101, or the first adhesive tape is located on the surface of the outermost second electrode 2 of the first winding area 101 facing away from the winding center O. For example, when the electrode assembly is wound and finished with a diaphragm 4, the outermost ring of the electrode assembly in the first winding area 101 is a diaphragm, and the first adhesive tape can be disposed on the surface of the diaphragm, or the first adhesive tape can be disposed on the surface of the outermost second electrode 2 of the first winding area 101 facing away from the winding center O.

[0078] In some embodiments, the first support member 31 includes a first coating. The outermost second electrode 2 in the first winding region 101 does not have a second active material layer on its surface facing away from the winding center O. The first coating is disposed on the surface of the outermost second electrode 2 in the first winding region 101 facing away from the winding center O. Specifically, the outermost ring of the second electrode 2 has a second active material layer disposed on one side of a portion of the first winding region 101, and the second active material layer is disposed on the surface facing the winding center O. The first coating is disposed on the surface of this portion facing away from the winding center O. The first coating includes at least one of a polymer or an inorganic material.

[0079] In some embodiments, the first support member 31 includes both the first tape and the first coating.

[0080] In some embodiments, the second support member 32 includes a second adhesive tape, which is adhered to the outermost surface of the second winding area 102, or the second adhesive tape is located on the surface of the outermost second electrode 2 of the second winding area 102 facing away from the winding center O. For example, when the electrode assembly is wound and finished with a diaphragm 4, the outermost ring of the electrode assembly in the second winding area 102 is a diaphragm, and the second adhesive tape can be disposed on the surface of the diaphragm, or the second adhesive tape can be disposed on the surface of the outermost second electrode 2 of the second winding area 102 facing away from the winding center O.

[0081] In some embodiments, the second support member 32 includes a second coating. The outermost second electrode 2 of the second winding region 102 does not have a second active material layer on its surface facing away from the winding center O. The second coating is disposed on the surface of the outermost second electrode 2 of the second winding region 102 facing away from the winding center O. Specifically, the outermost ring of the second electrode 2 has a second active material layer disposed on one side of a portion of the second winding region 102, and the second active material layer is disposed on the surface facing the winding center O. The second coating is disposed on the surface of this portion facing away from the winding center O. The second coating includes at least one of a polymer or an inorganic material.

[0082] In some embodiments, the second support member 32 includes both the second tape and the second coating.

[0083] In some embodiments, the third support 32 includes a third adhesive tape, which is adhered to the outermost surface of the third winding region 103, or the third adhesive tape is located on the surface of the outermost second electrode 2 of the third winding region 103 facing away from the winding center O. For example, when the electrode assembly is wound and finished with a diaphragm 4, the outermost ring of the electrode assembly in the third winding region 103 is a diaphragm, and the third adhesive tape can be disposed on the surface of the diaphragm, or the third adhesive tape can be disposed on the surface of the outermost second electrode 2 of the first winding region 101 facing away from the winding center O.

[0084] In some embodiments, the third support 33 includes a third coating. The outermost second electrode 2 of the third winding region 103 does not have a second active material layer on its surface facing away from the winding center O. The third coating is disposed on the surface of the outermost second electrode 2 of the third winding region 103 facing away from the winding center O. Specifically, the outermost ring of the second electrode 2 has a second active material layer disposed on one side of a portion of the third winding region 103, and the second active material layer is disposed on the surface facing the winding center O. The third coating is disposed on the surface of this portion facing away from the winding center O. The third coating includes at least one of a polymer or an inorganic material.

[0085] In some embodiments, the second support 32 includes both the third tape and the third coating.

[0086] This application also discloses an electrical device, including the battery in any of the above embodiments. In some embodiments, the electrical device of this application may be, but is not limited to, electronic devices, drones, backup power supplies, electric vehicles, electric motorcycles, electric-assisted bicycles, power tools, large household battery modules, etc.

[0087] The present application will be further described below through specific embodiments.

[0088] Taking a cylindrical aluminum-cased lithium-ion battery as an example, the positive electrode material is LiNi. 0.5 Co 0.2 Mn 0.3 O2, the negative electrode material is graphite; the diameter of the cylindrical aluminum shell is 35mm, the outermost ring of the negative electrode is a double-sided negative electrode with a thickness t1 of 0.15mm, the outermost ring of the electrode is a single-sided positive electrode with a thickness t2 of 0.064mm, then T=t1+t2=0.214mm.

[0089] According to the thickness and coverage curvature in Table 1, in Examples 1-14, support adhesive paper 1, adhesive paper 2 and adhesive paper 3 are respectively applied to the first winding area, the second winding area and the third winding area. The adhesive paper is applied symmetrically with respect to the center of each winding area.

[0090] In the comparative example, no supporting adhesive tape was applied in the first winding area, the second winding area, and the third winding area.

[0091] Loop test

[0092] Under an ambient temperature of 20±5℃, Step A: Charge at a constant current of 2C. When the voltage reaches the charging limit voltage of 4.2V, switch to constant voltage charging at 4.2V until the charging current reaches the cutoff current of 0.05C, and let it rest for 5 minutes. Step B: Discharge at a constant current of 10C until the termination voltage of 2.8V. Perform 700 charge-discharge cycles using Step A and Step B. After the cycle, perform a CT scan to observe the breakage of the outer electrode. Each group of batteries has 20 batteries tested in cycles, and the number of batteries with broken outer electrode is counted.

[0093] Table 1 shows the setting of the support adhesive paper and the results of the cyclic test in each embodiment and comparative example.

[0094] As shown in the test results in Table 1, the embodiments of this application, by providing a first support adhesive paper in the first winding area, can significantly reduce the number of batteries experiencing outer electrode breakage during cycling. This is because, by providing the first support adhesive paper in the first winding area, the gap difference between the first winding area and the second winding end section relative to the housing sidewall can be reduced or eliminated. When the electrode assembly expands to abut against the housing sidewall, the first support adhesive paper can provide support for the first winding area. During further cycling, it suppresses the expansion deformation of the electrode assembly in the first winding area, thereby reducing the risk of the outer electrode in the first winding area breaking due to expansion and stretching, and improving the battery's service life.

[0095] A comparison of Examples 1-3 and Examples 4-10 shows that by providing a second support adhesive paper in the second winding area and / or a third support adhesive paper in the third winding area, the gap difference between the second winding area and / or the third winding area and the second winding end section relative to the side wall of the housing can be further reduced or eliminated, thereby further reducing the risk of the outer electrode sheet breaking due to expansion and stretching.

[0096] It should be noted that while the preferred embodiments of this application are provided in the specification and accompanying drawings, this application can be implemented in many different forms and is not limited to the embodiments described in the specification. These embodiments are not intended to impose additional limitations on the content of this application; their purpose is to enable those skilled in the art to gain a more thorough and comprehensive understanding of the disclosure of this application. Furthermore, those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. An electrode assembly, the electrode assembly being a wound structure, the electrode assembly comprising a first electrode sheet and a second electrode sheet, the first electrode sheet comprising a first wound termination section, the second electrode sheet comprising a second wound termination section, the second wound termination section being located away from the winding center of the wound structure relative to the first wound termination section; the second wound termination section comprising a second wound end; the electrode assembly comprising a first winding region, the first winding region being the area covered by a ray extending from the winding center to the second wound end along the winding direction by rotating π / 3 radians, characterized in that: The electrode assembly further includes a first support member, at least a portion of which is disposed in the first winding area; the thickness of the portion of the first support member disposed in the first winding area is T1; the thickness of the first winding termination section is t1, and the thickness of the second winding termination section is t2; satisfying: T1≤T, where T=t1+t2.

2. The electrode assembly according to claim 1, characterized in that, 0.7T≤T1≤T.

3. The electrode assembly according to claim 2, characterized in that, The electrode assembly further includes a second winding region, which is the region remaining after removing the first winding region from the area covered by a ray extending 2π / 3 radians from the winding center to the end of the second winding along the winding direction; the electrode assembly satisfies any of the following conditions: (1) The first support member further includes a second region disposed in the second winding area, the thickness of the second region being T2, which satisfies: 0.5T≤T2≤0.7T; (2) The electrode assembly further includes a second support member, at least a portion of which is disposed in the second winding area; the thickness of the portion of the second support member disposed in the second winding area is T2. It satisfies: 0.5T≤T2≤0.7T.

4. The electrode assembly according to claim 3, characterized in that, The electrode assembly further includes a third winding region, which is the region remaining after removing the first winding region and the second winding region from the region covered by a ray extending π radians from the winding center to the second winding end along the winding direction; the electrode assembly satisfies any of the following conditions: (1) The first support member further includes a third region disposed in the third winding area, the thickness of the third region being T3, satisfying: 0.3T≤T3≤0.5T; (2) The electrode assembly further includes a third support member, at least a portion of which is disposed in the third winding area; the thickness of the portion of the third support member disposed in the third winding area is T3, satisfying: 0.3T≤T3≤0.5T.

5. The electrode assembly according to claim 1, characterized in that, The coverage arc of the first support portion located in the first winding area along the winding direction is w1, satisfying: π / 6≤w1≤π / 3.

6. The electrode assembly according to claim 3, characterized in that, Meet any of the following conditions: (1) The coverage arc of the second region along the winding direction is w2, which satisfies: π / 6≤w2≤π / 3; (2) The second support portion disposed in the second winding area covers the winding direction. The radian length is w2, which satisfies: π / 6 ≤ w2 ≤ π / 3.

7. The electrode assembly according to claim 4, characterized in that, Meet any of the following conditions: (1) The coverage arc of the third region along the winding direction is w3, which satisfies: π / 6≤w3≤π / 3; (2) The coverage arc of the third support member portion located in the third winding area along the winding direction is w3, which satisfies: π / 6≤w3≤π / 3.

8. The electrode assembly according to claim 4, characterized in that, At least one of the following conditions must be met: (1) The first support member includes at least one of the first tape or the first coating; (2) The second support member includes at least one of the second tape or the second coating; (3) The third support member includes at least one of a third tape or a third coating.

9. The electrode assembly according to claim 8, characterized in that, At least one of the following conditions must be met: (1) The first tape is adhered to the outermost surface of the first winding area or to the surface of the outermost second electrode sheet of the first winding area away from the winding center. (2) The second active material layer is not provided on the surface of the outermost second electrode sheet located in the first winding area away from the winding center, and the first coating is provided on the surface of the outermost second electrode sheet located in the first winding area away from the winding center. (3) The first coating comprises at least one of a polymer or an inorganic material; (4) The second tape is adhered to the outermost surface of the second winding area or to the surface of the outermost second electrode sheet of the second winding area that is away from the winding center. (5) The second active material layer is not provided on the surface of the outermost second electrode sheet located in the second winding area away from the winding center; the second coating is provided on the surface of the outermost second electrode sheet located in the second winding area away from the winding center. (6) The second coating comprises at least one of a polymer or an inorganic material; (7) The third tape is bonded to the outermost surface of the third winding area or to the surface of the outermost second electrode sheet of the third winding area that is away from the winding center. (8) The second active material layer is not provided on the surface of the outermost second electrode sheet in the third winding area away from the winding center, and the third coating layer is provided on the surface of the outermost second electrode sheet in the third winding area away from the winding center. (9) The third coating comprises at least one of a polymer or an inorganic material.

10. A battery comprising a housing and an electrode assembly as claimed in any one of claims 1-9, the housing being cylindrical and the electrode assembly being housed within the housing.

11. An electrical device comprising the battery of claim 10.

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