Electrode assembly, battery and electric equipment

Abstract

The invention relates to an electrode assembly, a battery and electric equipment, the electrode assembly is of a winding structure and comprises a first pole piece and a second pole piece, and a second winding ending section of the second pole piece is far away from a winding center of the winding structure relative to a first winding ending section of the first pole piece; the second winding ending section comprises a second winding tail end; the electrode assembly comprises a first winding area, the first winding area is an area covered by a ray rotating by pi / 3 radian in the winding direction from the winding center to the second winding tail end with the winding center as the circle center, and a first supporting piece is arranged in the first winding area. The first supporting piece is arranged in the first winding area, when the electrode assembly expands to abut against the side wall of the shell, the first supporting piece can support the first winding area, and in the further circulation process, expansion deformation of the electrode assembly in the first winding area is restrained; therefore, the risk of breakage of the outer-layer pole piece of the first winding area due to expansion and pulling is reduced, and the service life of the battery is prolonged.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of batteries, in particular to an electrode assembly, a battery and an electric device. BACKGROUND

[0002] Cylindrical batteries are widely used in electric vehicles, energy storage, power tools and other fields due to their advantages of easy manufacturing, high safety and the like. By reducing the gap between the winding core and the shell, the energy density of the battery can be improved, and in the drop and vibration working conditions, the movement of the winding core in the shell can be inhibited to avoid damage to other components such as the current collector plate, thereby improving the safety and reliability of the battery. SUMMARY

[0003] However, the inventors of the present application have found that the winding core is prone to fracture of the outer ring electrode tab during the cyclic use due to its special spiral winding structure, thereby affecting the service life of the battery. This is because, under the cyclic working condition, the active material in the electrode tab will expand in volume due to the behavior of lithium deintercalation, thereby pulling the current collector. With the cyclic expansion of the winding core, the tail section of the winding core will preferentially abut the shell side wall to form a support point, limiting the further extension of the current collector of the tail section. In the further cyclic expansion process, the winding core tends to expand to the gap at the spiral tail end, thereby causing the electrode tab at the spiral tail end gap to be more severely stretched, and further causing fracture, thereby affecting the normal use of the battery. In view of the above technical problems, the present application provides an electrode assembly, a battery and an electric device to reduce the risk of cyclic fracture of the electrode tab and improve the service life of the battery.

[0004] According to a first aspect of the present application, the present application provides an electrode assembly, the electrode assembly is in a winding structure, the electrode assembly comprises a first electrode tab and a second electrode tab, the first electrode tab comprises a first winding tail section, the second electrode tab comprises a second winding tail section, the second winding tail section is away from a winding center of the winding structure relative to the first winding tail section; the second winding tail section comprises a second winding end; the electrode assembly comprises a first winding area, the first winding area is an area covered by a ray with the winding center as a center, the ray rotating by an angle of π / 3 radians along a winding direction from the winding center to the second winding end, wherein: the electrode assembly further comprises a first support, at least a part of the first support is arranged in the first winding area; a thickness of the first support part arranged in the first winding area is T1; a thickness of the first winding tail section is t1, a thickness of the second winding tail section is t2; T1≤T is satisfied, wherein T=t1+t2. By arranging the first support in the first winding area, the gap difference of the first winding area and the second winding tail section relative to the side wall of the shell is reduced or eliminated. When the electrode assembly expands to abut against the side wall of the shell, the first support can provide support for the first winding area, and in further cycles, the expansion deformation of the electrode assembly in the first winding area is inhibited, thereby reducing the risk of breakage of the outer electrode tab of the first winding area due to expansion pulling and improving the service life of the battery.

[0005] In any one or more optional embodiments, 0.7T≤T1≤T. In this way, by adjusting T1 in the range of 0.7T-T, the first support can better fill the gap difference of the first winding area and the second winding tail section relative to the side wall of the shell, thereby better supporting the first winding area, further reducing the risk of breakage of the outer electrode tab of the first winding area due to expansion pulling, and improving the service life of the battery.

[0006] In any one or more optional embodiments, the electrode assembly further comprises: a second winding area, the second winding area is a remaining area in a region covered by a ray rotating by an angle of 2π / 3 radians along the winding direction from the winding center to the second winding end, the region being a region covered by the ray with the winding center as a center.

[0007] In any one or more optional embodiments, the first support further comprises a second area arranged in the second winding area, a thickness of the second area is T2, and 0.5T≤T2≤0.7T is satisfied.

[0008] In any one or more optional embodiments, the electrode assembly further comprises a second support, at least a part of the second support is arranged in the second winding area; a thickness of the second support part arranged in the second winding area is T2, and 0.5T≤T2≤0.7T is satisfied.

[0009] Thus, by setting the second region of the first support member or the second support member in the second winding zone, the gap difference of the second winding zone relative to the shell side wall at the second winding end is reduced or eliminated. When the electrode assembly expands to abut the shell side wall, the second region of the first support member or the second support member can provide support for the second winding zone, inhibit the expansion deformation of the electrode assembly in the second winding zone during further cycles, thereby reducing the risk of breakage of the outer layer electrode tab of the second winding zone due to expansion pulling and improving the service life of the battery.

[0010] In any one or more optional embodiments, the electrode assembly further comprises a third winding zone, which is a region remaining after the first winding zone and the second winding zone are removed from a region covered by a ray with the winding center as the center, the winding center to the second winding end, and the ray rotating π radians along the winding direction.

[0011] In any one or more optional embodiments, the first support member further comprises a third region provided in the third winding zone, and the thickness T3 of the third region satisfies: 0.3T≤T3≤0.5T.

[0012] In any one or more optional embodiments, the electrode assembly further comprises a third support member, and at least part of the third support member is provided in the third winding zone; the thickness T3 of the part of the third support member provided in the third winding zone satisfies: 0.3T≤T3≤0.5T.

[0013] Thus, by setting the third region of the first support member or the third support member in the third winding zone, the gap difference of the third winding zone relative to the shell side wall at the second winding end is reduced or eliminated. When the electrode assembly expands to abut the shell side wall, the third region of the first support member or the third support member can provide support for the third winding zone, inhibit the expansion deformation of the electrode assembly in the third winding zone during further cycles, thereby reducing the risk of breakage of the outer layer electrode tab of the third winding zone due to expansion pulling and improving the service life of the battery.

[0014] In any one or more optional embodiments, the part of the first support member provided in the first winding zone covers an arc w1 along the winding direction, and w1 satisfies: π / 6≤w1≤π / 3. Thus, the first support member can better provide support for the first winding zone, inhibit the expansion deformation of the electrode assembly in the first winding zone, further reduce the risk of breakage of the outer layer electrode tab of the first winding zone due to expansion pulling, and improve the service life of the battery.

[0015] In any one or more optional embodiments, the second region has a covered arc w2 along the winding direction, satisfying: π / 6≤w2≤π / 3.

[0016] In any one or more optional embodiments, the second support part provided in the second winding region has a covered arc w2 along the winding direction, satisfying: π / 6≤w2≤π / 3.

[0017] In this way, the second region of the first support or the second support can better support the second winding region, inhibit the expansion deformation of the electrode assembly in the second winding region, further reduce the risk of breakage of the outermost second electrode sheet in the second winding region due to expansion pulling, and improve the service life of the battery.

[0018] In any one or more optional embodiments, the third region has a covered arc w3 along the winding direction, satisfying: π / 6≤w3≤π / 3.

[0019] In any one or more optional embodiments, the third support part provided in the third winding region has a covered arc w3 along the winding direction, satisfying: π / 6≤w3≤π / 3.

[0020] In this way, the third region of the first support or the third support can better support the third winding region, inhibit the expansion deformation of the electrode assembly in the third winding region, further reduce the risk of breakage of the outermost second electrode sheet in the third winding region due to expansion pulling, and improve the service life of the battery.

[0021] In any one or more optional embodiments, the first support comprises at least one of a first adhesive tape or a first coating.

[0022] In any one or more optional embodiments, the second support comprises at least one of a second adhesive tape or a second coating.

[0023] In any one or more optional embodiments, the third support comprises at least one of a third adhesive tape or a third coating.

[0024] In any one or more optional embodiments, the first adhesive tape is attached to the outermost surface of the first winding region or to the surface of the outermost second electrode sheet in the first winding region facing away from the winding center.

[0025] In any one or more optional embodiments, the surface of the outermost second electrode sheet in the first winding region facing away from the winding center is not provided with a second active material layer, and the first coating is provided on the surface of the outermost second electrode sheet in the first winding region facing away from the winding center.

[0026] In any one or more optional embodiments, the first coating layer comprises at least one of a polymer or an inorganic material.

[0027] In any one or more optional embodiments, the second adhesive tape is attached to an outermost surface of the second winding region or a surface of an outermost second pole piece of the second winding region facing away from the winding center.

[0028] In any one or more optional embodiments, a surface of an outermost second pole piece of the second winding region facing away from the winding center is not provided with a second active material layer, and the second coating layer is provided on the surface of the outermost second pole piece of the second winding region facing away from the winding center.

[0029] In any one or more optional embodiments, the second coating layer comprises at least one of a polymer or an inorganic material.

[0030] In any one or more optional embodiments, the third adhesive tape is attached to an outermost surface of the third winding region or a surface of an outermost second pole piece of the third winding region facing away from the winding center.

[0031] In any one or more optional embodiments, a surface of an outermost second pole piece of the third winding region facing away from the winding center is not provided with a third active material layer, and the third coating layer is provided on the surface of the outermost second pole piece of the third winding region facing away from the winding center.

[0032] In any one or more optional embodiments, the third coating layer comprises at least one of a polymer or an inorganic material.

[0033] According to a second aspect of the present application, the present application further provides a battery comprising a housing and the electrode assembly in any one of the above embodiments, wherein the housing is in a cylindrical shape, and the electrode assembly is accommodated in the housing.

[0034] According to a third aspect of the present application, the present application further provides a power consuming device comprising the battery. BRIEF DESCRIPTION OF DRAWINGS

[0035] One or more embodiments are illustrated by way of example with reference to the accompanying drawings, in which elements having the same reference numerals designate similar elements throughout the several views and in which:

[0036] Figure 1 For some embodiments of the present application, a structural schematic diagram of a battery;

[0037] Figure 2 For some embodiments of the present application, a structural schematic diagram of an electrode assembly;

[0038] Figure 3 Structure diagram of the winding state of the pole piece in some embodiments of the present application;

[0039] Figure 4 Structure diagram of the winding state of the pole piece in some embodiments of the present application; Figure 3 View of the winding state of the pole piece in some embodiments of the present application along the second direction Y;

[0040] Figure 5 Structure diagram of the winding state of the pole piece in some embodiments of the present application; Figure 4 Enlarged view of A in some embodiments of the present application;

[0041] Figure 6 Structure diagram of the battery in some embodiments of the present application;

[0042] Figure 7 Structure diagram of the battery in some embodiments of the present application;

[0043] Figure 8 Structure diagram of the battery in some embodiments of the present application;

[0044] Figure 9 Structure diagram of the battery in some embodiments of the present application;

[0045] Figure 10 Structure diagram of the first support in some embodiments of the present application; Figure 9 Structure diagram of the first support in some embodiments of the present application;

[0046] Figure 11 Structure diagram of the battery in some embodiments of the present application;

[0047] Figure 12 Structure diagram of the first support in some embodiments of the present application; Figure 11 Structure diagram of the first support in some embodiments of the present application;

[0048] Figure 13 Structure diagram of the battery in some embodiments of the present application;

[0049] Figure 14 Structure diagram of the battery in some embodiments of the present application;

[0050] Meaning of the related reference signs:

[0051] Electrode assembly 100, first winding region 101, second winding region 102, third winding region 103;

[0052] Housing 200;

[0053] First pole piece 1, first winding end segment 10;

[0054] Second pole piece 2, second winding end segment 20, second winding end 21;

[0055] The first support 31, the first region 311, the second region 312, the third region 313, the second support 32, and the third support 33.

[0056] The diaphragm 4. DETAILED DESCRIPTION

[0057] For the purpose of promoting the understanding of the present application, the present application will be described in further detail below in conjunction with the accompanying drawings and specific embodiments. In the case of no conflict, the embodiments described below and the features in the embodiments 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 intervening elements can be present therebetween. When an element is described as being “connected to” another element, it can be directly connected to the other element or one or more intervening elements can be present therebetween. The terms “vertical”, “horizontal”, “left”, “right”, and similar expressions used in the present specification are for the purpose of illustration only.

[0058] Unless otherwise defined, all technical and scientific terms used in the present specification are the same as the meanings commonly understood by one of ordinary skill in the art to which the present application belongs. The terms used in the present specification are only for the purpose of describing the specific embodiments and are not intended to limit the present application. The term “and / or” used in the present specification includes any and all combinations of one or more of the associated listed items.

[0059] An embodiment of the present application discloses a battery, such as Figure 1 As shown, the battery includes an electrode assembly 100 and a housing 200, the electrode assembly 100 is encapsulated in the housing 200, and the housing 200 is in a columnar shape, which can be a cylindrical shape. As shown, Figures 2-5 The electrode assembly 100 includes an electrode sheet assembly wound around a winding center in a fixed winding direction, wherein the electrode sheet assembly includes a diaphragm 4, a first electrode sheet 1, a diaphragm 4, and a second electrode sheet 2 arranged in sequence, and after winding, the diaphragm 4 is arranged between the two adjacent turns of the first electrode sheet 1 and the second electrode sheet 2, thereby preventing direct contact between the first electrode sheet 1 and the second electrode sheet 2. One of the first electrode sheet 1 and the second electrode sheet 2 is a negative electrode sheet, and the other is a positive electrode sheet. For example, the first electrode sheet 1 is a positive electrode sheet, and the second electrode sheet 2 is a negative electrode sheet; or the first electrode sheet 1 is a negative electrode sheet, and the second electrode sheet 2 is a positive electrode sheet. The first electrode sheet 1 includes a first current collector and a first active material layer arranged on the surface of the first current collector; and the second electrode sheet 2 includes a second current collector and a second active material layer arranged on the surface of the second current collector.

[0060] As shown, Figures 3-5As shown, the first pole piece 1 includes a first winding tail section 10, and the second pole piece 2 includes a second winding tail section 20, wherein the first winding tail section 10 corresponds to the outermost winding layer of the first pole piece 1 and is a portion of the first pole piece 1 that is 90° in the opposite direction of the winding direction from the winding end of the first pole piece 1 with the winding center as the center; and the second winding tail section 20 corresponds to the outermost winding layer of the second pole piece 2 and is a portion of the second pole piece 2 that is 90° in the opposite direction of the winding direction from the winding end of the second pole piece 2 with the winding center as the center. The second winding tail section 20 is away from the winding center O of the winding structure relative to the first winding tail section 10, that is, the second pole piece 2 in the same winding layer of the winding pole piece assembly is located on the side of the first pole piece 1 away from the winding center O. The second winding tail section 20 includes a second winding end 21, and the second winding end 21 is located at the end of the second winding tail section 20 in the winding direction. The first winding tail section 10 includes a first winding end (not shown), and the first winding end is located at the end of the first winding tail section 10 in the winding direction. In some embodiments, the first pole piece 1 is a positive pole piece, and the second pole piece 2 is a negative pole piece. In the winding direction, the second winding end 21 is beyond the first winding end. In other embodiments, the first pole piece 1 is a negative pole piece, and the second pole piece 2 is a positive pole piece. In the winding direction, the first winding end is beyond the second winding end 21. In this way, it can be ensured that the negative active material layer can completely cover the opposite positive active material layer, and the risk of lithium precipitation during charging of the electrode assembly can be reduced.

[0061] As shown in FIG. 1, the electrode assembly 100 includes a first winding region 101, which is a sector region 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, and covers an arc of π / 3 radians (60°) in the winding direction. The electrode assembly 100 also includes a first support 31, and part or all of the first support 31 is arranged in the first winding region 101. Figure 2 Figure 6 As shown in FIG. 1, the electrode assembly 100 includes a first winding region 101, which is a sector region 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, and covers an arc of π / 3 radians (60°) in the winding direction. The electrode assembly 100 also includes a first support 31, and part or all of the first support 31 is arranged in the first winding region 101.

[0062] As shown in FIG. 1, the electrode assembly 100 includes a first winding region 101, which is a sector region 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, and covers an arc of π / 3 radians (60°) in the winding direction. The electrode assembly 100 also includes a first support 31, and part or all of the first support 31 is arranged in the first winding region 101.

[0063] By arranging the first support 31 in the first winding region 101, the gap difference between the first winding region 101 and the second winding tail section 20 relative to the side wall of the shell is reduced or eliminated. When the electrode assembly 100 expands to abut against the side wall of the shell 200, the first support 31 can provide support for the first winding region 101, and in further cycles, the expansion deformation of the electrode assembly 100 in the first winding region 101 is inhibited, thereby reducing the risk of breakage of the outer pole piece in the first winding region 101 due to expansion and tension, and improving the service life of the battery.​

[0064] In some embodiments, 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, 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, such as Figure 6 As shown, the first support member 31 is located on the outermost layer of the first winding area 101.

[0065] Specifically, such as Figure 6 As shown, 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.

[0066] 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.

[0067] In some embodiments, such as Figure 7 and Figure 8As shown, the electrode assembly 100 also 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.

[0068] In some embodiments, such as Figure 7 As shown, 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.

[0069] In other embodiments, such as Figure 8 As shown, the electrode assembly 100 also 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.

[0070] 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.

[0071] Similarly, in some embodiments, such as Figure 12 As shown, the thickness of the second region 312 can be a fixed value. In other embodiments, such as Figure 10As shown, 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 of the second winding zone 102 relative to the side wall of the shell 200 at the second winding end 20, achieving more sufficient filling of the gap difference. In some embodiments, the second support 32 is located at a portion of the second winding zone 102, and the thickness of the second support 32 at this portion can be a fixed value. In other embodiments, the second support 32 is located at a portion of the second winding zone 102, and the thickness of the second support 32 at this portion can gradually decrease along the winding direction.

[0072] In some embodiments, the second region 312 covers an arc w2 along the winding direction, and satisfies: π / 6≤w2≤π / 3. In this way, the second region 312 can better support the second winding zone 102, inhibit the expansion deformation of the electrode assembly 100 at the second winding zone 102, further reduce the risk of breakage of the outer layer electrode sheet of the second winding zone 102 due to expansion pulling, and improve the service life of the battery.

[0073] In some embodiments, the second support 32 located at the second winding zone 102 covers an arc w2 along the winding direction, i.e., the second support 32 located at the second winding zone 102 covers an arc w2 along the winding direction, and satisfies: π / 6≤w2≤π / 3. In this way, the second support 32 can better support the second winding zone 102, inhibit the expansion deformation of the electrode assembly 100 at the second winding zone 102, further reduce the risk of breakage of the outer layer electrode sheet of the second winding zone 102 due to expansion pulling, and improve the service life of the battery.

[0074] In some embodiments, as shown in Figure 9 and Figure 13 The electrode assembly 100 further includes a third winding zone 103, which is the remaining area in the area covered by rotating the radius from the winding center O to the second winding end 21 by π radians (180°) along the winding direction after removing the first winding zone 101 and the second winding zone 102. That is, the third winding zone 103 is the area covered by rotating π / 3 radians along the winding direction with the winding center O as the center and the radius from the second winding zone 102 to the side boundary of the first winding zone 101.

[0075] In some embodiments, as shown in Figure 9 and Figure 10As shown, the first support member 31 also 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.

[0076] 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.

[0077] 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.

[0078] Similarly, in some embodiments, such as Figure 11 and Figure 12 As shown, 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, such as Figure 9 and Figure 10 As shown, the thickness of the third region 313 gradually decreases along the winding direction, so that the thickness variation of the third region 313 matches 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 making the third region 313 more fully fill this gap difference. In some embodiments, the third support member 33 is located in a portion of the third winding region 103, and its thickness can be a fixed value. In other embodiments, the third support member 33 is located in a portion of the third winding region 103, and its thickness can gradually decrease along the winding direction.

[0079] In some embodiments, the third region 313 has a covered arc w3 in the winding direction, and satisfies: π / 6≤w3≤π / 3. In this way, the third region 313 can better support the third winding region 103, inhibit the expansion deformation of the electrode assembly 100 in the third winding region 103, further reduce the risk of breakage of the outermost electrode sheet in the third winding region 103 due to expansion pulling, and improve the service life of the battery.

[0080] In some embodiments, the third support 33 arranged in the third winding region 103 has a covered arc w3 in the winding direction, that is, the portion of the third support 33 located in the third winding region 103 has a covered arc w3 in the winding direction, and satisfies: π / 6≤w3≤π / 3. In this way, the third support 33 can better support the third winding region 103, inhibit the expansion deformation of the electrode assembly 100 in the third winding region 103, further reduce the risk of breakage of the outermost electrode sheet in the third winding region 103 due to expansion pulling, and improve the service life of the battery.

[0081] In some embodiments, the specific structure of the electrode assembly 100 can also be as shown in Figure 14 The first support 31 includes a first region 311 located in the first winding region 101 and a second region 312 arranged in the second winding region 102, that is, the first support 31 extends from the first winding region 101 to the second winding region 102 along the winding direction, with the difference that the third winding region 103 is provided with the third support 33.

[0082] In some embodiments, the first support 31 includes a first adhesive tape, which is attached to the outermost surface of the first winding region 101, or which is located on the surface of the outermost second electrode sheet 2 in the first winding region 101 facing away from the winding center O. For example, when the electrode assembly is wound and terminated with the separator 4, the outermost circle of the electrode assembly in the first winding region 101 is the separator, and the first adhesive tape can be arranged on the surface of the separator, or the first adhesive tape can be arranged on the surface of the outermost second electrode sheet 2 in the first winding region 101 facing away from the winding center O.

[0083] In some embodiments, the first support 31 includes a first coating layer, which is arranged on the surface of the outermost second electrode sheet 2 in the first winding region 101 facing away from the winding center O, without being provided with a second active material layer. Specifically, the outermost circle of the second electrode sheet 2 in the first winding region 101 is provided with a second active material layer on one side, and the second active material layer is arranged on the surface facing the winding center O. The first coating layer is arranged on the surface facing away from the winding center O. The first coating layer includes at least one of a polymer or an inorganic material.

[0084] In some embodiments, the first support 31 comprises both the first adhesive tape and the first coating.

[0085] In some embodiments, the second support 32 comprises a second adhesive tape, which is attached to the outermost surface of the second winding region 102 or which is located on the surface of the outermost second electrode sheet 2 of the second winding region 102 facing away from the winding center O. For example, when the electrode sheet assembly is terminated with the separator 4 after winding, the outermost circle of the electrode sheet assembly in the second winding region 102 is the separator, and the second adhesive tape can be arranged on the surface of the separator, or the second adhesive tape can be arranged on the surface of the outermost second electrode sheet 2 of the second winding region 102 facing away from the winding center O.

[0086] In some embodiments, the second support 32 comprises a second coating, which is arranged on the surface of the outermost second electrode sheet 2 of the second winding region 102 facing away from the winding center O, without a second active material layer. Specifically, the outermost circle of the second electrode sheet 2 in the second winding region 102 is provided with a second active material layer on one side, and the second active material layer is arranged on the surface facing the winding center O, and the second coating is arranged on the surface facing away from the winding center O. The second coating comprises at least one of a polymer or an inorganic material.

[0087] In some embodiments, the second support 32 comprises both the second adhesive tape and the second coating.

[0088] In some embodiments, the third support 32 comprises a third adhesive tape, which is attached to the outermost surface of the third winding region 103 or which is located on the surface of the outermost second electrode sheet 2 of the third winding region 103 facing away from the winding center O. For example, when the electrode sheet assembly is terminated with the separator 4 after winding, the outermost circle of the electrode sheet assembly in the third winding region 103 is the separator, and the third adhesive tape can be arranged on the surface of the separator, or the third adhesive tape can be arranged on the surface of the outermost second electrode sheet 2 of the first winding region 101 facing away from the winding center O.

[0089] In some embodiments, the third support 33 comprises a third coating, which is arranged on the surface of the outermost second electrode sheet 2 of the third winding region 103 facing away from the winding center O, without a second active material layer. Specifically, the outermost circle of the second electrode sheet 2 in the third winding region 103 is provided with a second active material layer on one side, and the second active material layer is arranged on the surface facing the winding center O, and the third coating is arranged on the surface facing away from the winding center O. The third coating comprises at least one of a polymer or an inorganic material.

[0090] In some embodiments, the second support 32 comprises the third adhesive tape and the third coating layer mentioned above at the same time.

[0091] The application also discloses a power-using device comprising the battery in any of the above embodiments. In some embodiments, the power-using device of the application can be, but is not limited to, an electronic device, a drone, a backup power supply, an electric vehicle, an electric motorcycle, an electric power-assisted bicycle, an electric tool, a household large-scale battery module, etc.

[0092] The application will be further described below through specific embodiments.

[0093] For example, a cylindrical aluminum shell lithium ion battery, wherein the positive electrode material is LiNi 0.5 Co 0.2 Mn 0.3 O2, the negative electrode material is graphite; the cylindrical aluminum shell has a diameter of 35 mm, the outermost circle of the negative electrode tab is a double-sided negative electrode, the thickness t1 of the negative electrode tab is 0.15 mm, the outermost circle of the tab is a single-sided positive electrode tab, and the thickness t2 of the single-sided positive electrode tab is 0.064 mm, so T=t1+t2=0.214 mm.

[0094] In Examples 1-14, the support adhesive paper 1, the adhesive paper 2 and the adhesive paper 3 are respectively attached to the first winding area, the second winding area and the third winding area according to the thickness and the covering radian in Table 1, and the adhesive papers are symmetrically attached to the center of each winding area.

[0095] In the Comparative Example, no support adhesive paper is attached to the first winding area, the second winding area and the third winding area.

[0096] Cycle test

[0097] Under the condition that the ambient temperature is 20±5℃, step A: constant rate 2C constant current charging, when the voltage reaches the charging limit voltage 4.2V, change to 4.2V constant voltage charging, until the charging current is the cutoff current 0.05C, and stand for 5 min; step B: 10C constant current discharging to the terminal voltage 2.8V; steps A and B are performed for 700 times of charge-discharge cycles, and after the end, CT scanning test is performed to observe the fracture of the outermost circle of the tab, the number of batteries for cycle test in each group is 20, and the number of batteries with fractured outermost circle of the tab is counted.

[0098] Table 1 shows the setting of the support adhesive paper and the cycle test results in each embodiment and the comparative example

[0099]

[0100] As can be seen from the test results in Table 1, the embodiments of the present application can greatly reduce the number of batteries in which the outer ring tab is broken during the cycle by providing the first support adhesive tape in the first winding area. This is because, by providing the first support adhesive tape in the first winding area, the gap difference of the first winding area and the second winding end section relative to the side wall of the shell can be reduced or eliminated. When the electrode assembly expands to abut the side wall of the shell, the first support adhesive tape can provide support for the first winding area, and in the further cycle process, the expansion deformation of the electrode assembly in the first winding area is inhibited, thereby reducing the risk of breakage of the outer layer tab in the first winding area due to expansion and pulling, and improving the service life of the battery.

[0101] As can be seen from the comparison of Examples 1-3 and Examples 4-10, by providing the second support adhesive tape in the second winding area and / or the third support adhesive tape in the third winding area, the gap difference of the second winding area and / or the third winding area and the second winding end section relative to the side wall of the shell can be further reduced or eliminated, thereby further reducing the risk of breakage of the outer layer tab due to expansion and pulling.

[0102] It should be noted that the preferred embodiments of the present application are given in the specification and drawings of the present application, but the present 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 be additional limitations on the content of the present application, and the purpose of providing these embodiments is to make the understanding of the disclosure of the present application more thorough and comprehensive for those of ordinary skill in the art. And, those of ordinary skill in the art can make improvements or changes based on the above description, and all such improvements and changes shall fall within the scope of protection of the appended claims of the present application.

Claims

1. An electrode assembly in a wound structure, the electrode assembly comprising a first electrode tab and a second electrode tab, the first electrode tab comprising a first winding tail section, the second electrode tab comprising a second winding tail section, the second winding tail section being away from a winding center of the wound structure relative to the first winding tail section; the second winding tail section comprising a second winding end; the electrode assembly comprising a first winding region, the first winding region being a region covered by a ray from the winding center to the second winding end rotating by an angle of π / 3 radians in a winding direction with the winding center as a center; characterized in that: the electrode assembly further comprises a first support, at least a portion of the first support being disposed in the first winding region; a thickness of the first support portion disposed in the first winding region being T1; a thickness of the first winding tail section being t1, a thickness of the second winding tail section being t2; satisfying: T1≤T, where T=t1+t2. 0.7T≤T1≤T.

2. The electrode assembly of claim 1, wherein, The electrode assembly further comprises a second winding region, the second winding region being a region remaining after removing the first winding region in a region covered by a ray from the winding center to the second winding end rotating by an angle of 2π / 3 radians in the winding direction with the winding center as a center; the electrode assembly satisfying any one of the following conditions:

3. The electrode assembly of claim 2, wherein, (1) the first support further comprises a second region disposed in the second winding region, a thickness of the second region being T2, satisfying: 0.5T≤T2≤0.7T; (2) the electrode assembly further comprises a second support, at least a portion of the second support being disposed in the second winding region; a thickness of the second support portion disposed in the second winding region being T2, satisfying: 0.5T≤T2≤0.7T. The electrode assembly further comprises a third winding region, the third winding region being a region remaining after removing the first winding region and the second winding region in a region covered by a ray from the winding center to the second winding end rotating by an angle of π radians in the winding direction with the winding center as a center; the electrode assembly satisfying any one of the following conditions:

4. The electrode assembly of claim 3, wherein, (1) the first support further comprises a third region disposed in the third winding region, a thickness of the third region being T3, satisfying: 0.3T≤T3≤0.5T; (2) the electrode assembly further comprises a third support, at least a portion of the third support being disposed in the third winding region; a thickness of the third support portion disposed in the third winding region being T3, satisfying: 0.3T≤T3≤0.5T. The first support portion disposed in the first winding region covers an angle of w1 in the winding direction, satisfying: π / 6≤w1≤π / 3.

5. The electrode assembly of claim 1, wherein, Any one of the following conditions is satisfied:

6. The electrode assembly of claim 3, wherein, (1) the second region covers an angle of w2 in the winding direction, satisfying: π / 6≤w2≤π / 3; (2) the second support portion disposed in the second winding region covers an angle of w2 in the winding direction, satisfying: π / 6≤w2≤π / 3. Any one of the following conditions is satisfied:

7. The electrode assembly of claim 4, wherein, ​ (1) the third region has a covered arc w3 in the winding direction, and π / 6≤w3≤π / 3 is satisfied; (2) the third support part provided in the third winding region has a covered arc w3 in the winding direction, and π / 6≤w3≤π / 3 is satisfied.

8. The electrode assembly of claim 4, wherein, At least one of the following conditions is satisfied: (1) the first support part comprises at least one of a first adhesive tape or a first coating layer; (2) the second support part comprises at least one of a second adhesive tape or a second coating layer; (3) the third support part comprises at least one of a third adhesive tape or a third coating layer.

9. The electrode assembly of claim 8, wherein, At least one of the following conditions is satisfied: (1) the first adhesive tape is attached to an outermost surface of the first winding region or a surface of an outermost second pole piece in the first winding region facing away from the winding center; (2) a surface of an outermost second pole piece in the first winding region facing away from the winding center is not provided with a second active material layer, and the first coating layer is provided on a surface of an outermost second pole piece in the first winding region facing away from the winding center; (3) the first coating layer comprises at least one of a polymer or an inorganic material; (4) the second adhesive tape is attached to an outermost surface of the second winding region or a surface of an outermost second pole piece in the second winding region facing away from the winding center; (5) a surface of an outermost second pole piece in the second winding region facing away from the winding center is not provided with a second active material layer, and the second coating layer is provided on a surface of an outermost second pole piece in the second winding region facing away from the winding center; (6) the second coating layer comprises at least one of a polymer or an inorganic material; (7) the third adhesive tape is attached to an outermost surface of the third winding region or a surface of an outermost second pole piece in the third winding region facing away from the winding center; (8) a surface of an outermost second pole piece in the third winding region facing away from the winding center is not provided with a second active material layer, and the third coating layer is provided on a surface of an outermost second pole piece in the third winding region facing away from the winding center; (9) the third coating layer comprises at least one of a polymer or an inorganic material.

10. A battery comprising a housing and the electrode assembly according to any one of claims 1-9, wherein the housing is in a cylindrical shape, and the electrode assembly is accommodated in the housing.

11. An electrical device comprising the battery according to claim 10.

Images