Secondary batteries and electrical devices

Abstract

The present application discloses a secondary battery and an electrical device, comprising: a housing, an electrode assembly, a top cover, and an insulating sheet. The insulating sheet comprises a first covering portion, a second covering portion connected to the first covering portion, and a third covering portion connected to the second covering portion. The connection between the first and second covering portions is provided with at least one first indentation extending along a length direction X, and the connection between the second and third covering portions is provided with at least one second indentation extending along a height direction Y. By providing the first and second indentations on the insulating sheet, the present application enables the insulating member to bend and wrap around the electrode assembly through the first and second indentations, thereby reducing the risk of the insulating sheet tearing and achieving insulation and protection of the electrode assembly by the insulating sheet.

Description

[0001] This application is a divisional application of the invention patent application with application number 202410605385.8, application date May 16, 2024, and name “Secondary Battery and Electrical Device”. Technical Field

[0002] The present application belongs to the field of battery technology, and specifically relates to a secondary battery and an electrical device. Background Art

[0003] The insulating sheet is a crucial component of secondary batteries, primarily used to insulate and protect the internal electrode assembly, ensuring safety within the assembly. To facilitate the wrapping of the insulating sheet around the electrode assembly, creases are provided on the sheet. These creases typically take the form of tooth-like lines, formed by multiple through-holes arranged in a straight line. This prevents the insulating film from fully covering the entire surface of the electrode assembly after wrapping. This can easily lead to tearing of the insulating sheet, potentially causing a short circuit and reducing the yield rate of the insulating sheet wrapping. Summary of the Invention

[0004] Purpose of the invention: The embodiments of the present application provide a secondary battery and an electrical device, which can increase the internal insulation reliability of the electrode assembly and improve the coating yield of the insulating sheet by providing an indentation on the insulating sheet.

[0005] Technical solution: A secondary battery of the present application includes:

[0006] a housing, wherein the housing has a receiving cavity;

[0007] an electrode assembly, the electrode assembly being disposed in the accommodating cavity, the electrode assembly having a length direction X and a height direction Y perpendicular to the length direction X;

[0008] a top cover sheet connected to the shell and covering the accommodating cavity;

[0009] an insulating sheet, the insulating sheet comprising a first covering portion, a second covering portion connected to the first covering portion, and a third covering portion connected to the second covering portion, the first covering portion, the second covering portion, and the third covering portion collectively forming an insulating cavity, the electrode assembly being at least partially accommodated in the insulating cavity; at least one first indentation extending along the length direction X is provided at the connection between the first covering portion and the second covering portion, and at least one second indentation extending along the height direction Y is provided at the connection between the second covering portion and the third covering portion; the first indentation and the second indentation each have an opening and a bottom wall opposite the opening; the opening extends through a surface of the insulating sheet toward or away from the electrode assembly;

[0010] In which, the third covering portion has a third edge and a fourth edge relative to each other along the height direction Y, and the second indentation has a third end close to the third edge and a fourth end close to the fourth edge along the height direction Y; wherein, the third edge and the third end have a minimum distance D mm in the height direction Y, the fourth edge and the fourth end have a minimum distance E mm in the height direction Y, and the third edge and the fourth edge have a maximum dimension B mm in the height direction Y, satisfying: 0.63≤(BED) / B≤0.99.

[0011] In some embodiments, the insulating sheet further satisfies: 0.68≤(BED) / B≤0.99.

[0012] In some embodiments, the insulating sheet further satisfies at least one of the following characteristics:

[0013] a) 10≤B≤500;

[0014] b) 0<D≤50;

[0015] c)0<E≤50.

[0016] In some embodiments, the first covering portion has a first edge and a second edge relative to each other along the length direction X, and the first indentation has a first end close to the first edge and a second end close to the second edge along the length direction X; wherein, a minimum distance C mm is between the first edge and the first end in the length direction X, a minimum distance J mm is between the second edge and the second end in the length direction X, and a maximum dimension A mm is between the first edge and the second edge in the length direction X, satisfying: 0.53≤(ACJ) / A≤0.99.

[0017] In some embodiments, the insulating sheet further satisfies: 0.7≤(ACJ) / A≤0.99.

[0018] In some embodiments, the insulating sheet further satisfies at least one of the following characteristics:

[0019] d)10≤A≤2000;

[0020] e) 0<C≤50;

[0021] f)0<J≤50.

[0022] In some embodiments, a minimum distance F mm is between the surface of the bottom wall and the surface of the insulating sheet away from the opening; the opening has a maximum width H mm, satisfying the following: 0.001≤H×F≤0.25.

[0023] In some embodiments, the insulating sheet further satisfies: 0.01≤H×F≤0.2.

[0024] In some embodiments, the insulating sheet has a maximum thickness of G mm, and the insulating sheet further satisfies:

[0025] 0.1≤F / G≤0.95.

[0026] In some embodiments, the insulating sheet further satisfies at least one of the following characteristics:

[0027] g) 0.01<H≤5;

[0028] h) 0.01<F<1;

[0029] i)0.01≤G≤1.

[0030] In some embodiments, the insulating sheet further satisfies at least one of the following characteristics:

[0031] j) 0.03≤F≤0.18;

[0032] k)0.1≤G≤0.2.

[0033] In some embodiments, the electrode assembly includes two large surfaces, two side surfaces connecting the two large surfaces, and a bottom surface connecting the two large surfaces and the two side surfaces; the electrode assembly further has a width direction Z perpendicular to the length direction X and the height direction Y respectively;

[0034] The first covering portion is in contact with the bottom surface;

[0035] The second covering portion is provided on both sides of the first covering portion along the width direction Z and is in contact with the two large surfaces;

[0036] The third covering portion is provided on both sides of the second covering portion along the length direction X and is in contact with at least a portion of the two side surfaces.

[0037] In some embodiments, the insulating sheet further comprises:

[0038] A fourth covering portion is connected to the first covering portion; the fourth covering portion is provided on both sides of the first covering portion along the length direction X and is in contact with parts of the two side surfaces.

[0039] In some embodiments, the first covering portion has a positioning hole, which passes through the first covering portion along the thickness direction of the first covering portion. There are two positioning holes, one of which is close to the first edge and the other is close to the second edge.

[0040] In some embodiments, the positioning hole is circular, and the positioning hole has a diameter K mm, satisfying: 0<K≤10; or

[0041] The positioning hole is elliptical, and the positioning hole has a major axis of 1 mm, satisfying: 0<I<10.

[0042] In some embodiments, the cross-sectional shape of the first indentation and / or the second indentation along a direction perpendicular to the thickness of the insulating sheet is at least one of a circle, an ellipse, a semicircle, a polygon, and an irregular shape.

[0043] In some embodiments, the present application further provides an electrical device, comprising the secondary battery described above, wherein the secondary battery is used to power the electrical device.

[0044] Beneficial effect: A secondary battery according to an embodiment of the present application comprises: a shell having a receiving cavity; an electrode assembly, the electrode assembly being arranged in the receiving cavity, the electrode assembly having a length direction X and a height direction Y perpendicular to the length direction X; a top cover sheet, the top cover sheet being connected to the shell and covering the receiving cavity; an insulating sheet, the insulating sheet comprising a first covering portion, a second covering portion connected to the first covering portion, and a third covering portion connected to the second covering portion, the first covering portion, the second covering portion, and the third covering portion together forming an insulating cavity, the electrode assembly being at least partially received in the insulating cavity; the connection between the first covering portion and the second covering portion At least one first indentation extending along the length direction X is provided at the joint, and at least one second indentation extending along the height direction Y is provided at the connection between the second covering portion and the third covering portion; the first indentation and the second indentation both have an opening and a bottom wall opposite to the opening; the opening passes through the surface of the insulating sheet facing toward or away from the electrode assembly; wherein, the third covering portion has a third edge and a fourth edge opposite to each other along the height direction Y, and the second indentation has a third end close to the third edge and a fourth end close to the fourth edge along the height direction Y; wherein, the third edge and the third end have a minimum distance D mm in the height direction Y, the fourth edge and the fourth end have a minimum distance E mm in the height direction Y, and the third edge and the fourth edge have a maximum dimension B mm in the height direction Y, satisfying the following: 0.63≤(BED) / B≤0.99. In the secondary battery of the present application, by setting the first indentation and the second indentation on the insulating sheet, the insulating member can be bent and wrapped around the electrode assembly through the first indentation and the second indentation, thereby reducing the risk of tearing of the insulating sheet and achieving insulation and protection of the electrode assembly by the insulating sheet; when the range of 0.63≤(BED) / B≤0.99 is met, the length of the second indentation along the height direction X can be within a reasonable range, ensuring that the insulating sheet can be completely bent, and the risk of tearing can be reduced, thereby improving the yield rate of the insulating sheet wrapping the electrode assembly.

[0045] It can be understood that the electrical device in the embodiment of the present application can include all the technical features and beneficial effects of the above-mentioned secondary battery, which will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0047] Figure 1 A schematic structural diagram of a secondary battery provided in an embodiment of the present application;

[0048] Figure 2 A schematic diagram of the structure of a bent insulating sheet provided in an embodiment of the present application;

[0049] Figure 3 A schematic diagram of the structure of an insulating sheet after unfolding provided in an embodiment of the present application;

[0050] Figure 4 A partially enlarged schematic diagram of the first indentation or the second indentation provided in an embodiment of the present application;

[0051] Figure 5 A schematic diagram showing that the cross-sectional shape of the first indentation or the second indentation provided in an embodiment of the present application is a hexagon;

[0052] Figure 6 A schematic diagram showing that the cross-sectional shape of the first indentation or the second indentation provided in an embodiment of the present application is a trapezoid;

[0053] Figure 7 A schematic diagram showing that the cross-sectional shape of the first indentation or the second indentation provided in an embodiment of the present application is a semicircular shape;

[0054] Figure 8 This is an illustration of an irregular cross-sectional shape of the first indentation or the second indentation provided in an embodiment of the present application;

[0055] Figure 9 A schematic diagram showing that the cross-sectional shape of the first indentation or the second indentation provided in an embodiment of the present application is a semi-elliptical shape;

[0056] Figure 10 A schematic diagram showing an irregular cross-sectional shape of the first indentation or the second indentation provided in an embodiment of the present application;

[0057] Figure 11 A schematic diagram showing an irregular cross-sectional shape of the first indentation or the second indentation provided in an embodiment of the present application;

[0058] Figure 12 A schematic diagram of the structure of another insulating sheet after unfolding provided in an embodiment of the present application;

[0059] Figure 13 for Figure 12 A partial enlarged schematic diagram of the M in the middle;

[0060] Figure 14 for Figure 12 The intention of the local enlargement of N in the middle;

[0061] Figure 15 A schematic diagram of a local structure in which the positioning hole provided in the embodiment of the present application is elliptical;

[0062] Figure 16 An axial view of an insulating sheet provided in an embodiment of the present application with a fourth covering portion added;

[0063] Figure 17 An axial view of an insulating sheet provided in an embodiment of the present application with a cutout provided in the third covering portion;

[0064] Figure 18 A schematic diagram of the three-dimensional structure of the electrode assembly provided in an embodiment of the present application;

[0065] Figure markings: 10-shell, 101-accommodating cavity, 20-electrode assembly, 201-large surface, 202-side surface, 203-bottom surface, 30-top cover sheet, 40-insulating sheet, 401-first covering portion, 402-second covering portion, 403-third covering portion, 404-fourth covering portion, 411-first indentation, 412-second indentation, 413-opening, 414-bottom wall, 4011-first edge, 4012-second edge, 4013-positioning hole, 4111-first end, 4112-second end, 4031-third edge, 4032-fourth edge, 4121-third end, 4122-fourth end, 50-insulating cavity. DETAILED DESCRIPTION

[0066] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the embodiments described are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making creative efforts are within the scope of protection of this application.

[0067] In the description of this application, it should be understood that the terms "length", "width", "thickness", "upper", "lower", "top", "bottom", "inner", "outer", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended only to facilitate the description of this application and simplify the description. They do not indicate or imply that the devices or elements referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore should not be understood as limiting this application. In the description of this application, "plurality" means two or more, and "at least one" means one, two, or more than two, unless otherwise clearly and specifically defined.

[0068] See also Figure 1 、 Figure 2 、 Figure 3 and Figure 4 The present embodiment provides a secondary battery, comprising: a housing 10, an electrode assembly 20, a top cover sheet 30, and an insulating sheet 40; the housing 10 has a receiving cavity 101; the electrode assembly 20 is disposed in the receiving cavity 101, and the electrode assembly 20 has a length direction X and a height direction Y perpendicular to the length direction X; the top cover sheet 30 is connected to the housing 10 and covers the receiving cavity 101; the insulating sheet 40 includes a first covering portion 401, a second covering portion 402 connected to the first covering portion 401, and a third covering portion 403 connected to the second covering portion 402, the first covering portion 401, the second covering portion 402, and The third covering portion 403 together encloses an insulating cavity 50, and the electrode assembly 20 is at least partially accommodated in the insulating cavity 50; at least one first indentation 411 extending along the length direction X is provided at the connection between the first covering portion 401 and the second covering portion 402, and at least one second indentation 412 extending along the height direction Y is provided at the connection between the second covering portion 402 and the third covering portion 403; the first indentation 411 and the second indentation 412 each have an opening 413 and a bottom wall 414 opposite to the opening 413; the opening 413 extends through the surface of the insulating sheet 40 toward or away from the electrode assembly 20; see further Figure 12 、 Figure 13 The third covering portion 403 has a third edge 4031 and a fourth edge 4032 opposite to each other along the height direction Y, and the second indentation 412 has a third end 4121 close to the third edge 4031 and a fourth end 4122 close to the fourth edge 4032 along the height direction Y; wherein, the third edge 4031 and the third end 4121 have a minimum distance D mm in the height direction Y, the fourth edge 4032 and the fourth end 4122 have a minimum distance E mm in the height direction Y, and the third edge 4031 and the fourth edge 4032 have a maximum dimension B mm in the height direction Y, satisfying the following: 0.63≤(BED) / B≤0.99.

[0069] It is understood that the secondary battery provided in this embodiment, by providing the first indentation 411 and the second indentation 412 on the insulating sheet 40, allows the insulating sheet 40 to be bent and wrapped around the electrode assembly 20 via the first indentation 411 and the second indentation 412, thereby reducing the risk of tearing of the insulating sheet 40 and achieving insulation and protection of the electrode assembly 20 by the insulating sheet 40. The range of (BED) / B can be any one of 0.63, 0.64, 0.65, 0.66, 0.67, 0.68, 0.69, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95, 0.96, 0.97, 0.98, and 0.99, or a range between any two values. The value of BED can be used to limit the length of the second indentation 412 along the height direction X. If the length of the second indentation 412 is too small, the insulating sheet 40 may bend along the indentation and fail to form, resulting in the insulating sheet 40 being unable to cover the electrode assembly 20, and the yield rate of the covered electrode assembly 20 may not meet the requirements. The length of the second indentation 412 should not exceed the maximum dimension B of the third covering portion 403 along the height direction X. The length of the second indentation 412 should also not be too large, otherwise there is a risk of the insulating sheet 40 bending and tearing along the indentation.

[0070] In some embodiments, the insulating sheet further satisfies: 0.68≤(BED) / B≤0.99.

[0071] In some embodiments, the maximum dimension B mm between the third edge 4031 and the fourth edge 4032 in the height direction Y further satisfies the following: 10 ≤ B ≤ 500. For example, B can be any value of 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 150, 200, 250, 300, 350, 400, or 500, or a range between any two values. The maximum dimension B mm further satisfies the following: 50 ≤ B ≤ 300.

[0072] In some embodiments, the minimum distance D between the third edge 4031 and the third end 4121 in the height direction Y further satisfies: 0<D≤50; for example, D can be any value of 1, 2, 5, 8, 10, 20, 30, 40, 50 or a range between any two values.

[0073] In some embodiments, the minimum distance E between the fourth edge 4032 and the fourth end 4122 in the height direction Y further satisfies: 0<E≤50; for example, E can be any value of 1, 2, 5, 8, 10, 20, 30, 40, 50 or a range between any two values.

[0074] In some embodiments, see Figure 12 、 Figure 14The first covering portion 401 has a first edge 4011 and a second edge 4012 opposite to each other along the length direction X, and the first indentation 411 has a first end 4111 close to the first edge 4011 and a second end 4112 close to the second edge 4012 along the length direction X; wherein, the first edge 4011 and the first end 4111 have a minimum distance C mm in the length direction X, the second edge 4012 and the second end 4112 have a minimum distance J mm in the length direction X, and the first edge 4011 and the second edge 4012 have a maximum dimension A mm in the length direction X, satisfying the following: 0.53≤(ACJ) / A≤0.99.

[0075] It is understood that the range of (ACJ) / A can be any one of 0.53, 0.54, 0.55, 0.56, 0.57, 0.58, 0.59, 0.6, 0.65, 0.75, 0.8, 0.85, 0.9, 0.95, 0.96, 0.97, 0.98, and 0.99, or a range between any two values. The value of ACJ can be used to limit the length of the first indentation 411 along the length direction X. If the length of the first indentation 411 is too small, it is easy for the insulating sheet 40 to bend along the indentation and fail to form, resulting in the insulating sheet 40 being unable to cover the electrode assembly 20, and the yield of the covered electrode assembly 20 not meeting the requirements. The length of the first indentation 411 will not exceed the maximum dimension A of the first covering portion 401 along the length direction X, and the length of the first indentation 411 should not be too large, otherwise there will be a risk of the insulating sheet 40 bending and tearing along the indentation.

[0076] In some embodiments, the insulating sheet further satisfies: 0.7≤(ACJ) / A≤0.99.

[0077] In some embodiments, the maximum dimension A mm between the first edge 4011 and the second edge 4012 in the length direction X further satisfies: 10 ≤ A ≤ 2000. For example, A can be any value of 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 150, 200, 250, 300, 350, 400, 500, 600, 700, 800, 900, 1000, 1200, 1400, 1600, 1800, or 2000, or a range between any two values. The maximum dimension A mm further satisfies: 100 ≤ A ≤ 300.

[0078] In some embodiments, the minimum distance Cmm between the first edge 4011 and the first end 4111 in the length direction X further satisfies: 0<C≤50; for example, C can be any value of 1, 2, 5, 8, 10, 20, 30, 40, 50 or a range between any two values.

[0079] In some embodiments, the minimum distance Jmm between the second edge 4012 and the second end 4112 in the length direction X further satisfies: 0<J≤50; for example, J can be any value of 1, 2, 5, 8, 10, 20, 30, 40, 50 or a range between any two values.

[0080] In some embodiments, some common dimension measurement methods can be selected to measure any one of the dimensions A, C, J, B, E, and D; for example, a vernier caliper, micrometer, or other measuring tools can be used to measure the corresponding dimensions, or projection measurement can be used to obtain an image of the opening 413 using a projection measurement device (such as a digital microscope or an image measuring instrument) and measure the corresponding dimensions.

[0081] In some embodiments, see further Figure 4 The surface of the bottom wall 414 and the surface of the insulating sheet 40 away from the opening 413 have a minimum distance F mm; the opening 413 has a maximum width H mm, satisfying: 0.001≤H×F≤0.25.

[0082] It should be noted that, see Figure 4 The first indentation 411 or the second indentation 412 can be understood as a groove set on the surface of the insulating sheet 40, having a groove morphology, which is different from the tooth-shaped fold morphology. The groove morphology is conducive to the direct bending of the first covering portion 401, the second covering portion 402, and the third covering portion 403 at the connection point, which can provide a clear guiding direction for bending. The groove itself can also serve as a reference line for bending, making the bending more accurate and consistent; in addition, by forming an indentation with a groove morphology, stress can be dispersed and stress concentration of the insulating sheet 40 during bending can be reduced, reducing or preventing cracking or damage of the insulating sheet 40 during bending, and improving the reliability and durability of the insulating sheet 40; at the same time, the groove morphology can also increase the bending radius of the insulating sheet 40 during bending, so that the first indentation 411 and the second indentation 412 reduce the stress during bending, and reduce deformation and damage during the bending process; furthermore, the groove morphology of the indentation can also provide additional support and rigidity during the bending process, which helps to maintain the stability of the overall shape of the insulating sheet 40 after bending.

[0083] In some embodiments, see further Figure 4, the maximum width H mm of the opening 413 is used to limit the overall width of the indentation; the minimum distance F mm from the surface of the bottom wall 414 to the surface of the insulating sheet 40 away from the opening 413 is used to limit the remaining thickness of the insulating sheet 40 after the indentation is set on the surface. It should be further explained that there is position uncertainty in the insulating sheet 40 during the bonding process with the electrode assembly 20, so that the opening 413 can be facing the electrode assembly 20 or away from the electrode assembly 20. Therefore, the definition of F varies with the direction of the opening 413. Specifically, the opening 413 passes through the surface of the insulating sheet 40 facing the electrode assembly 20 and the surface of the bottom wall 414 and the surface of the insulating sheet 40 away from the electrode assembly 20 have a minimum distance of F mm; or, the opening 413 passes through the surface of the insulating sheet 40 away from the electrode assembly 20 and the bottom wall 414 and the surface of the insulating sheet 40 close to the electrode assembly 20 have a minimum distance of F mm. However, no matter which setting method is used, F can be understood as the remaining thickness of the insulating sheet 40 after the indentation is set on the insulating sheet 40; the range of H×F can be any one of 0.001, 0.002, 0.005, 0.008, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.12, 0.15, 0.18, 0.2, 0.21, 0.22, 0.23, 0.24, 0.25 or the range between any two values; when the insulating sheet 40 satisfies the range of 0.001≤H×F≤0.25, the maximum opening size and the remaining minimum thickness of the first indentation 411 and the second indentation 412 can be within a reasonable range to ensure that the insulating sheet 40 can be completely bent to improve the yield rate of the insulating sheet 40 covering the electrode assembly 20.

[0084] In some embodiments, the insulating sheet 40 further satisfies: 0.01≤H×F≤0.2.

[0085] In some embodiments, H and F can be measured using conventional dimensional measurement methods. For example, for the maximum width H of opening 413, when the shape of opening 413 is circular, square, or rectangular, a vernier caliper, micrometer, or other measuring tool can be used to measure the corresponding dimension. When the opening is an irregular shape, image processing methods can also be used for measurement. For example, an image of the opening can be captured, loaded into image processing software, and then measured using the software. Alternatively, projection measurement can be used to capture an image of opening 413 using a projection measurement device (such as a digital microscope or image measuring instrument) and measure the corresponding dimensions. Accordingly, the minimum distance F can be measured directly using a vernier caliper or a thickness gauge.

[0086] In some embodiments, see further Figure 4The insulating sheet 40 has a maximum thickness of G mm, and the insulating sheet 40 further satisfies the following: 0.1 ≤ F / G ≤ 0.95. It is understood that the range of F / G can be any one of 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, and 0.95, or a range between any two values. When the range of 0.1 ≤ F / G ≤ 0.95 is satisfied, the minimum distance F can be further ensured to be within reasonable requirements, thereby improving the degree of bending of the insulating sheet 40 along the indentation and reducing the risk of tearing of the insulating sheet 40, thereby increasing the internal insulation reliability of the electrode assembly 20 and improving the coating yield of the insulating sheet 40.

[0087] In some embodiments, the maximum width H mm of the opening 413 further satisfies the following: 0.01 < H ≤ 5. For example, H can be any value selected from 0.011, 0.015, 0.02, 0.03, 0.04, 0.05, 0.08, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, or 5, or a range between any two values. If the maximum width H is too large, the insulating sheet 40 may tear along the indentation, resulting in insulation failure. If the maximum width H is too small, the insulating sheet 40 may bend along the indentation and fail to form, thus failing to cover the electrode assembly 20. This may result in the insulating sheet 40 being scrapped and the yield rate of the insulating sheet 40 covering the electrode assembly 20 failing to meet requirements. Furthermore, the maximum width H mm further satisfies the following range: 0.1 ≤ H ≤ 3.

[0088] In some embodiments, the minimum distance F mm between the surface of the bottom wall 414 and the surface of the insulating sheet 40 away from the opening 413 further satisfies the following: 0.01 < F < 1. For example, F can be any value among 0.011, 0.015, 0.02, 0.03, 0.04, 0.05, 0.08, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, and 0.9, or a range between any two values. If the minimum distance F is too small, the insulating sheet may easily tear along the indentation, resulting in insulation failure. If the minimum distance F is too large, the insulating sheet 40 may bend along the indentation and fail to form, resulting in the insulating sheet 40 being unable to cover the electrode assembly 20, and the coating yield rate may not meet the requirements.

[0089] Furthermore, the minimum distance F mm between the surface of the bottom wall 414 and the surface of the insulating sheet 40 away from the opening 413 further satisfies: 0.03≤F≤0.18.

[0090] In some embodiments, the maximum thickness G mm of the insulating sheet 40 satisfies the following relationship: 0.01 ≤ G ≤ 1. For example, G can be any value among 0.01, 0.02, 0.03, 0.04, 0.05, 0.08, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or 1, or a range between any two values. It is understood that G is always greater than F.

[0091] Furthermore, the maximum thickness G mm of the insulating sheet 40 satisfies: 0.1≤G≤0.2.

[0092] In some embodiments, see further Figure 2 、 Figure 3 and Figure 18 The electrode assembly 20 includes two large surfaces 201, two side surfaces 202 connecting the two large surfaces 201, and a bottom surface 203 connecting the two large surfaces 201 and the two side surfaces 202; the electrode assembly 20 also has a width direction Z perpendicular to the length direction X and the height direction Y respectively; the first covering portion 401 is in contact with the bottom surface 203; the second covering portion 402 is provided on both sides of the first covering portion 401 along the width direction Z and in contact with the two large surfaces 201; the third covering portion 403 is provided on both sides of the second covering portion 402 along the length direction X and in contact with at least part of the two side surfaces 202. It can be understood that Figure 3 Taking the insulating sheet 40 as an example, it can be seen that the first covering portion 401 is provided with one, which is directly fitted with a bottom surface 203 of the electrode assembly 20; the second covering portion 402 is provided with two, which are symmetrically arranged in the width direction Z along the first covering portion 401 and are fitted with the two large surfaces 201; the third covering portion 403 is provided with four, and the two third covering portions 403 are symmetrically arranged on both sides of the second covering portion 402 along the length direction X as a group, and then the four third covering portions 403 are bent relative to the second covering portion 402 and fitted with the two side surfaces 202, as shown in FIG. Figure 2 It can be seen that part of the third covering portion 403 overlaps after bonding; in some other embodiments, there can be two third covering portions 403, which are arranged on both sides of any second covering portion 402. As long as the third covering portion can completely cover the side surface when bonding with the side surface 202, insulation protection of the electrode assembly 20 can be guaranteed.

[0093] In some embodiments, see Figure 16 or Figure 17 The insulating sheet further includes a fourth covering portion 404, which is connected to the first covering portion 401; the fourth covering portion 404 is provided on both sides of the first covering portion 401 along the length direction X and is in contact with parts of the two side surfaces 202. It is understood that Figure 16For example, two fourth covering portions 404 are provided, which are arranged on both sides of the first covering portion along the length direction X. The fourth covering portion 404 is used to fit with the portion of the side surface 202. The fourth covering portion 404 is used to further increase the insulation reliability inside the electrode assembly 20. This is because the fourth covering portion 404 can cover the side of the electrode assembly 20 close to the bottom wall of the shell 10 to avoid a short circuit caused by contact between the electrode assembly 20 and the bottom wall of the shell.

[0094] In some embodiments, see further Figure 17 The third covering portion 403 also has a cutout for attaching adhesive tape to secure the insulating sheet 40 to the electrode assembly 20. Once the adhesive tape is attached to the cutout, it secures the insulating sheet 40 to the electrode assembly 20, reducing the need for hot-melt processing and improving production efficiency. The specific bonding process is as follows: After the side surfaces of the third covering portion 403 are bonded, the cutout exposes the electrode assembly 20. At this point, adhesive tape, such as an insulating cable tie, tape, or foam, can be wrapped around the electrode assembly 20 to secure and insulate it.

[0095] In some embodiments, see further Figure 14 and Figure 15 The first covering portion 401 has a positioning hole 4013 extending through the first covering portion 401 along its thickness. Two positioning holes 4013 are provided, one of which is located near the first edge 4011 and the other near the second edge 4012. It will be appreciated that the positioning holes 4013 are used to secure the insulating sheet 40, facilitating uniform coating of any electrode assembly 20, thereby improving coating efficiency and ensuring a consistent fit between the insulating sheet 40 and the electrode assembly 20.

[0096] In some embodiments, see further Figure 14 and Figure 15 For different coatings, the positioning holes can have different shapes, such as circular, elliptical, polygonal or irregular shapes. Figure 14 It can be seen that the positioning hole 4013 is circular and has an aperture K mm, which satisfies: 0<K≤10; for example, K can be any value among 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or a range between any two values, and the aperture K can be obtained by caliper or projection. Figure 15 It can be seen that the positioning hole 4013 is an ellipse, and the positioning hole 4013 has a major axis I mm, satisfying: 0<I<10; for example, I can be any value of 1, 2, 3, 4, 5, 6, 7, 8, 9 or a range between any two values. The major axis I represents the longest line segment that can be obtained by connecting two points on the ellipse, which can be measured by a caliper or projection.

[0097] In some embodiments, the cross-sectional shape of the first indentation 411 and the second indentation 412 along the direction perpendicular to the thickness of the insulating sheet 40 is at least one of a circle, an ellipse, a semicircle, a polygon, and an irregular shape; see further Figures 4 to 11 ,in, Figure 4 The cross-sectional shape is rectangular, Figure 5 The cross-sectional shape is hexagonal. Figure 6 The cross-sectional shape is trapezoidal. Figure 7 The cross-sectional shape is semicircular. Figure 8 The cross-sectional shape is an arc. Figure 9 The cross-sectional shape is semi-elliptical. Figure 10 and Figure 11 The cross-sectional shapes are all irregular. The above cross-sectional shapes can be obtained by direct measurement or image measurement. The first indentation 411 or the second indentation 412 of different shapes can increase the internal insulation reliability of the electrode assembly and improve the coating yield of the insulation sheet.

[0098] In some embodiments, see further Figure 3 The first covering portion 401 is further provided with a plurality of spaced through holes for allowing the electrolyte to pass through, thereby ensuring the electrolyte's infiltration effect on the electrode assembly. The shape of the through holes can be any one of circular, polygonal, elliptical, and irregular shapes.

[0099] In some embodiments, the present application also provides an electrical device, including the secondary battery provided in this embodiment, and the secondary battery is used to power the electrical device. Among them, the electrical device can be an application device such as a vehicle, a mobile phone, a portable device, a laptop computer, a ship, a spacecraft, an electric toy, and an electric tool. The vehicle can be a new energy vehicle, and the new energy vehicle can be a pure electric vehicle, a hybrid vehicle, or an extended-range vehicle, etc.; the spacecraft includes an airplane, a rocket, a space shuttle, and a spacecraft, etc.; the electric toy includes a fixed or mobile electric toy, such as a game console, an electric car toy, an electric ship toy, and an electric airplane toy, etc.; the electric tool includes a metal cutting electric tool, a grinding electric tool, an assembly electric tool, and an electric tool for railways, such as an electric drill, an electric grinder, an electric wrench, an electric screwdriver, an electric hammer, an impact drill, a concrete vibrator, and an electric planer, etc. The embodiments of the present application do not impose any special restrictions on the above-mentioned electrical devices.

[0100] Example 1

[0101] Provided is a secondary battery comprising: Figure 3 The insulating sheet 40 shown in FIG. 4 has a maximum thickness G of 0.2 mm. The overall structure of the secondary battery is as follows: Figure 1As shown, the insulating sheet 40 is provided with a first indentation 411 and a second indentation 412, and the H and F values ​​of the first indentation 411 and the second indentation 412 are the same; the cross-sectional schematic diagram of the first indentation 411 and the second indentation 412 is shown as Figure 4 , the cross-section is rectangular; combined Figure 13 and Figure 14 In the insulating sheet 40 provided in Example 1, A is 214 mm, C is 32 mm, J is 32 mm, B is 267 mm, E is 41 mm, and D is 41 mm.

[0102] Further examples 2-11 are provided, and the specific structure is the same as that of Example 1, except that the value of at least one of A, C, J, B, E, and D is different from that of Example 1. Further comparative examples 1-2 are provided, and the specific structure is the same as that of Comparative Example 1, except that Comparative Examples 1-2 do not satisfy the range of 0.53≤(ACJ) / A≤0.99. Comparative Examples 3-4 are provided, and the specific structure is the same as that of Comparative Example 1, except that Comparative Examples 3-4 do not satisfy the range of 0.63≤(BED) / B≤0.99. For the specific data and test results of the above Examples 1, 2-11, and Comparative Examples 1-4, please refer to Table 1.

[0103] The vibration test specifically refers to a vibration test in accordance with national safety regulations to confirm whether the insulating sheet 40 will tear during use and whether the insulation will fail. The specific test conditions of the vibration test are: 100% SOC, 300kgf, fixture: XYZ axis vibration, acceleration: 0.5g, frequency: 5-2000Hz, sweep rate: 1oct / min sweep once; the vibration meets the passing standard: no fire, no explosion (EUCAR HL≤4); the vibration reference standard is: VW8000.

[0104] The specific test process for the insulation sheet coating yield is as follows: the robot grasps the insulation sheet 40 and bends each side along the indentation. After the insulation sheet is bent, the top surface needs to be hot-melt fixed to the lower plastic. If the insulation sheet is not bent properly, the insulation sheet cannot be hot-melt fixed to the lower plastic and is discovered by visual inspection before flowing to the next process. Among them, a coating yield of more than 99.5% indicates that the coating yield meets the requirements.

[0105] Table 1

[0106]

[0107] It can be seen from Table 1 that Examples 1-11 meet the requirements of vibration testing and coating yield, and can increase the reliability of internal insulation of the electrode assembly 20; it can be seen from the test results of Example 1 and Comparative Examples 1-4 that the indentation length affects the bending and forming of the insulating sheet 40 along the indentation, which may cause the insulating sheet 40 to be unable to coat the electrode assembly 20, resulting in the insulating sheet coating yield being difficult to meet the requirements; it may also cause the insulating sheet 40 to tear along the indentation during the vibration test, and the insulation failure leads to the failure of the vibration test.

[0108] Furthermore, in Example 1, the first indentation 411 and the second indentation 412 both satisfy: 0.001≤H×F≤0.25. For specific structural dimension parameters, see Table 2.

[0109] Examples 12-15

[0110] A secondary battery is provided, the specific structure of which is the same as that of embodiment 1, except that the F values ​​of the first indentation and the second indentation are different.

[0111] Example 16

[0112] A secondary battery is provided, the specific structure of which is the same as that of embodiment 1, except that the maximum thickness G of the insulating sheet 40 is 0.5 mm, and the values ​​of F of the first indentation and the second indentation are different.

[0113] Examples 17-21

[0114] A secondary battery is provided, the specific structure of which is the same as that of embodiment 1, except that the H values ​​of the first indentation and the second indentation are different.

[0115] Examples 22-26

[0116] A secondary battery is provided, the specific structure of which is the same as that of Example 8, and the values ​​of H of the first indentation and the second indentation are the same as those of Example 8, except that the values ​​of F of the first indentation and the second indentation are different.

[0117] Comparative Examples 5-8

[0118] Among them, the specific structure of comparative examples 5-6 is the same as that of embodiment 1, except that the H values ​​of the first indentation and the second indentation are different, and the value of H×F does not satisfy the range of 0.001≤H×F≤0.25.

[0119] The specific structure of Comparative Examples 7-8 is the same as that of Example 1, except that the F values ​​of the first indentation and the second indentation are different, and the value of H×F does not satisfy the range of 0.001≤H×F≤0.25.

[0120] The secondary batteries of Example 1, Examples 12-26 and Comparative Examples 5-8 were subjected to vibration tests and insulation sheet coating yield tests. Specific test results are shown in Table 2. The test process corresponding to the test results in Table 2 is the same as that of Table 1.

[0121] Table 2

[0122]

[0123]

[0124] It can be seen from Table 2 that the secondary batteries of Example 1 and Examples 12-26 meet the range of 0.001≤H×F≤0.25, meet the requirements of vibration test and coating yield, and can increase the reliability of internal insulation of the electrode assembly 20; through the comparison of Example 1, Examples 12-26 and Comparative Examples 5-8, it can be seen that when H is too small or F is too large, the insulating sheet 40 is difficult to bend along the indentation and difficult to coat, which affects the coating yield; when H is too large or F is too small, the insulating sheet 40 may be torn along the indentation during the vibration test, and there is a risk of insulation failure leading to vibration test failure.

[0125] Examples 27-31

[0126] A secondary battery is provided, which has the same specific structure as that of embodiment 1 and satisfies the range of 0.1≤F / G≤0.95. The difference is that the maximum thickness G of the insulating sheet 40 has a different value.

[0127] Examples 32-36

[0128] A secondary battery is provided, the specific structure of which is the same as that of Example 22, and both satisfy the range of 0.1≤F / G≤0.95, except that the maximum thickness G of the insulating sheet 40 has a different value.

[0129] Examples 37-38

[0130] A secondary battery is provided, which has the same specific structure as that of embodiment 1, except that the value of H×F satisfies the range of 0.001≤H×F≤0.25, but the value of F / G does not satisfy the range of 0.1≤F / G≤0.95.

[0131] Comparative Examples 9-10

[0132] A secondary battery is provided, the specific structure of which is the same as that of Example 1, except that the H values ​​of the first indentation and the second indentation are different, the value of H×F does not satisfy the range of 0.001≤H×F≤0.25, and the value of the maximum thickness G of the insulating sheet 40 does not satisfy the range of 0.1≤F / G≤0.95.

[0133] The specific data and test results of Example 1, Example 22, Examples 27-38 and Comparative Examples 9-10 are shown in Table 3. The test process corresponding to the test results in Table 3 is the same as that of Table 1.

[0134] Table 3

[0135]

[0136] It can be seen from Table 3 that the secondary batteries of Examples 27-36 further meet the range of 0.001≤H×F≤0.25 and 0.1≤F / G≤0.95, which can further increase the reliability of the internal insulation of the electrode assembly 20 within this range; Examples 37-38 meet 0.001≤H×F≤0.25 but do not meet 0.1≤F / G≤0.95, resulting in a slightly low coating yield of the insulating sheet; It can be seen from Comparative Examples 9-10 that after simultaneously meeting the ranges of 0.001≤H×F≤0.25 and 0.1≤F / G≤0.95, the vibration test effect of the insulating sheet 40 can be further met and the coating effect of the insulating sheet 40 can be improved. It can be seen from Examples 27-31 that the size of G affects the difficulty of bending the insulating sheet 40. When the size of F is too small relative to that of G, the insulating sheet is easily torn along the indentation during the vibration test, and insulation failure causes failure of the vibration test. When the size of F is too large relative to that of G, the insulating sheet is difficult to bend along the indentation and difficult to wrap, which affects the wrapping yield.

[0137] The above is a detailed introduction to a secondary battery and an electrical device provided in the embodiments of the present application, and specific examples are used to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the technical solutions and core ideas of the present application; ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some of the technical features therein with equivalents; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A secondary battery, characterized in that: include: a housing, wherein the housing has a receiving cavity; an electrode assembly, the electrode assembly being disposed in the accommodating cavity, the electrode assembly having a length direction X and a height direction Y perpendicular to the length direction X; a top cover sheet connected to the shell and covering the accommodating cavity; an insulating sheet, the insulating sheet comprising a first covering portion, a second covering portion connected to the first covering portion, and a third covering portion connected to the second covering portion, the first covering portion, the second covering portion, and the third covering portion collectively forming an insulating cavity, the electrode assembly being at least partially accommodated in the insulating cavity; at least one first indentation extending along the length direction X is provided at the connection between the first covering portion and the second covering portion, and at least one second indentation extending along the height direction Y is provided at the connection between the second covering portion and the third covering portion; the first indentation and the second indentation each have an opening and a bottom wall opposite the opening; the opening extends through a surface of the insulating sheet toward or away from the electrode assembly; The first covering portion has a first edge and a second edge opposite to each other along the longitudinal direction X, and the first indentation has a first end close to the first edge and a second end close to the second edge along the longitudinal direction X; a minimum distance C mm is defined between the first edge and the first end in the longitudinal direction X, a minimum distance J mm is defined between the second edge and the second end in the longitudinal direction X, and a maximum dimension A mm is defined between the first edge and the second edge in the longitudinal direction X, satisfying the following: 0.53≤(ACJ) / A≤0.99; The third covering portion has a third edge and a fourth edge relative to each other along the height direction Y, and the second indentation has a third end close to the third edge and a fourth end close to the fourth edge along the height direction Y; wherein, the third edge and the third end have a minimum distance D mm in the height direction Y, the fourth edge and the fourth end have a minimum distance E mm in the height direction Y, and the third edge and the fourth edge have a maximum dimension B mm in the height direction Y, satisfying the following: 0.63≤(BED) / B≤0.

99.

2. The secondary battery according to claim 1, wherein The insulating sheet further satisfies: 0.68≤(BED) / B≤0.

99.

3. The secondary battery according to claim 1, wherein The insulating sheet further satisfies at least one of the following characteristics: a) 10≤B≤500; b) 0<D≤50; c)0<E≤50.

4. The secondary battery according to claim 1, wherein The insulating sheet further satisfies: 0.7≤(ACJ) / A≤0.

99.

5. The secondary battery according to claim 1, characterized in that: The insulating sheet further satisfies at least one of the following characteristics: d)10≤A≤2000; e) 0<C≤50; f)0<J≤50.

6. The secondary battery according to claim 1, characterized in that: A minimum distance F mm is between the surface of the bottom wall and the surface of the insulating sheet away from the opening; the opening has a maximum width H mm, satisfying the following: 0.001≤H×F≤0.

25.

7. A secondary battery according to claim 6, characterized in that: The insulating sheet further satisfies: 0.01≤H×F≤0.

2.

8. The secondary battery according to claim 6, characterized in that: The insulating sheet has a maximum thickness of G mm, and the insulating sheet further satisfies: 0.1≤F / G≤0.

95.

9. The secondary battery according to claim 8, characterized in that: The insulating sheet further satisfies at least one of the following characteristics: g) 0.01<H≤5; h) 0.01<F<1; i)0.01≤G≤1.

10. The secondary battery according to claim 9, characterized in that: The insulating sheet further satisfies at least one of the following characteristics: j) 0.03≤F≤0.18; k)0.1≤G≤0.

2.

11. The secondary battery according to claim 1, characterized in that: The electrode assembly includes two large surfaces, two side surfaces connecting the two large surfaces, and a bottom surface connecting the two large surfaces and the two side surfaces; the electrode assembly also has a width direction Z perpendicular to the length direction X and the height direction Y respectively; The first covering portion is in contact with the bottom surface; The second covering portion is provided on both sides of the first covering portion along the width direction Z and is in contact with the two large surfaces; The third covering portion is provided on both sides of the second covering portion along the length direction X and is in contact with at least a portion of the two side surfaces.

12. The secondary battery according to claim 11, characterized in that: The insulating sheet further comprises: A fourth covering portion is connected to the first covering portion; the fourth covering portion is provided on both sides of the first covering portion along the length direction X and is in contact with parts of the two side surfaces.

13. The secondary battery according to claim 1, characterized in that: The first covering portion has a positioning hole, which passes through the first covering portion along a thickness direction of the first covering portion. Two positioning holes are provided, one of the two positioning holes is close to the first edge, and the other is close to the second edge.

14. The secondary battery according to claim 13, characterized in that: The positioning hole is circular, and the positioning hole has a hole diameter of K mm, satisfying: 0<K≤10; or The positioning hole is elliptical, and the positioning hole has a major axis of 1 mm, satisfying: 0<I<10.

15. The secondary battery according to claim 1, characterized in that: The cross-sectional shape of the first indentation and / or the second indentation along a direction perpendicular to the thickness of the insulating sheet is at least one of a circle, an ellipse, a semicircle, a polygon, and an irregular shape.

16. An electrical device, characterized in that: The secondary battery comprises the secondary battery according to any one of claims 1 to 15, and the secondary battery is used to supply power to the electrical device.

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