Cylindrical secondary battery, battery pack, and electric device

Abstract

The embodiment of the utility model provides a cylindrical secondary battery, a battery pack and a power utilization device, the cylindrical secondary battery comprises a shell, a top cover, an electrode assembly and a first insulating part, the first insulating part comprises a first part and a second part which are connected with each other, the first part surrounds the outer peripheral surface of the electrode assembly so as to maintain tightening and insulation of a winding structure, and the second part surrounds the outer peripheral surface of the electrode assembly; the second part provides insulation protection for the first end face of the electrode assembly, and the first insulation piece serves as an integral component and has the two functions of providing insulation protection and keeping tightening for the electrode assembly at the same time. Compared with the conventional technical scheme that the winding structure is bound by an adhesive tape and the circumferential angle of the winding structure is insulated and protected by insulating gummed paper, the structure of the cylindrical secondary battery is simplified, the assembly of the first insulating part is completed through fewer process steps in the production and processing of the cylindrical secondary battery, and the production efficiency of the cylindrical secondary battery is improved. And the production efficiency of the cylindrical secondary battery can be improved.

Description

Technical Field

[0001] The present application relates to the field of energy storage technology, and in particular to a cylindrical secondary battery, a battery pack and an electrical device. Background Art

[0002] Cylindrical secondary batteries, such as lithium-ion cylindrical batteries, are widely used in various fields and are usually prepared using electrode assemblies with a winding structure. The electrode assemblies with a winding structure need to be tightened and insulated, and the preparation process is complicated, which affects production efficiency. Utility Model Content

[0003] The purpose of the embodiments of the present application is to provide a cylindrical secondary battery, a battery pack and an electrical device to simplify the structure of the cylindrical secondary battery and the process steps of manufacturing the cylindrical secondary battery and improve the production efficiency of the cylindrical secondary battery.

[0004] In a first aspect, the present application provides a cylindrical secondary battery, comprising: a shell having a shell opening; a top cover connected to the shell and sealing the shell opening; an electrode assembly having a winding structure, arranged in the shell, and the electrode assembly having a first end face facing the top cover; a first insulating member, comprising a first part and a second part connected to each other, the first part surrounding the outer circumference of the electrode assembly for at least one week, and the second part being arranged on the first end face; along the axial direction of the cylindrical secondary battery, the length of the electrode assembly is L1, and the length of the first part is L2; ​​0.5≤L2 / L1≤1. In an embodiment of the present application, the first insulating member includes a first part and a second part that are interconnected, the first part surrounds the outer peripheral surface of the electrode assembly to facilitate maintaining the tightening and insulation of the winding structure, and the second part provides insulating protection for the first end face of the electrode assembly. The first insulating member, as an integral component, has the two functions of providing insulating protection and maintaining tightening for the electrode assembly. Compared with the conventional cylindrical secondary battery, which uses a tape to bind the winding structure and an insulating tape to insulate the circumferential angle of the winding structure, it is convenient to simplify the structure of the cylindrical secondary battery, and in the production and processing of the cylindrical secondary battery, the assembly of the first insulating member is completed through fewer process steps, which is beneficial to improving the production efficiency of the cylindrical secondary battery.

[0005] In one or more embodiments, 0.7≤L2 / L1≤1, and L2 / L1 adopts a larger ratio so as to improve the tightness of the first portion around the electrode assembly and maintain the tightening of the winding structure.

[0006] In one or more embodiments, 0.9≤L2 / L1≤1, and L2 / L1 adopts a larger ratio so as to further improve the tightness of the first portion around the electrode assembly and maintain the tightening of the winding structure.

[0007] In one or more embodiments, the cylindrical secondary battery is a cylindrical secondary battery; the radius of the electrode assembly is R; the width of the second part along the radial direction of the cylindrical secondary battery is L3; 0.08≤L3 / R≤0.32, so that the second part provides insulation protection around the first end surface of the electrode assembly.

[0008] In one or more embodiments, 8 mm ≤ R ≤ 35 mm, which is conducive to realizing a large-capacity cylindrical secondary battery.

[0009] In one or more embodiments, along the direction surrounding the outer circumference of the electrode assembly, when the first insulating member is flattened, the length of the first insulating member is W1; 1<W1 / (2πR)≤1.5, and the first insulating member surrounds the outer circumference of the electrode assembly for more than one circle, which is beneficial to the insulation protection and tightening of the electrode assembly.

[0010] In one or more embodiments, along the direction around the outer circumference of the electrode assembly, the first insulating member includes a starting section and an ending section, and the ending section has an overlapping area with the starting section. The width of the overlapping area is W2, 1mm≤W2≤5mm, so that the starting section and the ending section of the first insulating member can be well overlapped, so that the first insulating member can be more firmly arranged on the electrode assembly.

[0011] In one or more embodiments, 1 mm ≤ W2 ≤ 3 mm, which is beneficial to reducing the space occupied by the first insulating member and improving the energy density of the cylindrical secondary battery.

[0012] In one or more embodiments, the shell includes a side wall and a bottom wall, the side wall includes a recess, and the recess is recessed into the shell; along the axial direction, the electrode assembly is arranged between the bottom wall and the recess; along the axial direction, the electrode assembly, the second part, and the recess are arranged in sequence, and the projection of the recess falls within the projection of the second part. The recess is conducive to suppressing the movement of the electrode assembly, and the second part is conducive to forming an insulating isolation between the first end face of the electrode assembly and the recess of the shell.

[0013] In one or more embodiments, the electrode assembly includes a first pole piece, a second pole piece and a diaphragm; wherein the first pole piece has opposite polarity to the second pole piece, the first pole piece includes a first current collector and a first active material, the first current collector includes a first main body area and a first empty foil area, the first active material is arranged in the first main body area, the first empty foil area includes a first flattened area, the first flattened area is away from the first main body area to form a first end face, the second part insulates and isolates the first flattened area from the recessed portion, the electrode assembly is a full-ear structure, which is beneficial to reducing the internal resistance of the cylindrical secondary battery, and the second part is beneficial to forming insulation isolation between the flattened area of ​​the electrode assembly and the recessed portion of the shell.

[0014] In one or more embodiments, the material of the first insulating member includes one of polyimide, polyethylene terephthalate, polypropylene or polyvinyl chloride, and the above material has good insulation properties and mechanical strength, which is beneficial to provide insulation protection between the first end face of the electrode assembly and the shell, and facilitates keeping the electrode assembly tightened.

[0015] In one or more embodiments, the first insulating member is an integral structural member, so that the first insulating member as a whole has good mechanical strength and the first insulating member can be assembled through fewer process steps.

[0016] In a second aspect, the present application provides a battery pack including the above-mentioned cylindrical secondary battery.

[0017] In a third aspect, the present application provides an electrical device, including the above-mentioned cylindrical secondary battery or battery pack.

[0018] The cylindrical secondary battery, battery pack and electrical device provided in the embodiments of the present application, the cylindrical secondary battery includes a shell, a top cover, an electrode assembly and a first insulating member, the first insulating member includes a first part and a second part connected to each other, the first part surrounds the outer peripheral surface of the electrode assembly to facilitate maintaining the tightening and insulation of the winding structure, the second part provides insulation protection for the first end face of the electrode assembly, the first insulating member as an integral component, and has the two functions of providing insulation protection and maintaining tightening for the electrode assembly. Compared with the conventional cylindrical secondary battery, which uses tape to bind the winding structure and uses insulating tape to insulate the circumferential angle of the winding structure, it is convenient to simplify the structure of the cylindrical secondary battery, and in the production and processing of the cylindrical secondary battery, the assembly of the first insulating member is completed through fewer process steps, which is beneficial to improving the production efficiency of the cylindrical secondary battery.

[0019] Of course, any product implementing the present application does not necessarily need to achieve all of the advantages described above at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application, and a person skilled in the art can also obtain other drawings based on these drawings.

[0021] Figure 1 A schematic diagram of the structure of a cylindrical secondary battery provided in an embodiment of the present application;

[0022] Figure 2 A schematic cross-sectional view of a cylindrical secondary battery provided in an embodiment of the present application;

[0023] Figure 3A schematic structural diagram of a first insulating member of a cylindrical secondary battery provided in an embodiment of the present application;

[0024] Figure 4 A schematic cross-sectional structure diagram of a first insulating member of a cylindrical secondary battery provided in an embodiment of the present application;

[0025] Figure 5 A schematic structural diagram of a first insulating member of a cylindrical secondary battery provided in an embodiment of the present application in a flattened state;

[0026] Figure 6 for Figure 2 A magnified view of middle;

[0027] Figure 7 is a schematic diagram of the structure of a battery pack provided in an embodiment of the present application;

[0028] Figure 8 It is a structural schematic diagram of a first type of electrical device provided in an embodiment of the present application;

[0029] Fig. 9 It is a structural schematic diagram of a second electrical device provided in an embodiment of the present application.

[0030] The reference numerals are as follows:

[0031] Shell 10, shell opening 101, side wall 11, recess 111, bottom wall 12, top cover 20, electrode terminal 21, current cut-off device 22, electrode assembly 30, first end surface 31, outer peripheral surface 32, first insulating member 40, first portion 41, second portion 42, starting section 43, ending section 44, overlapping area 45;

[0032] Cylindrical secondary battery 100, battery pack 200, power-consuming device 300;

[0033] Axis L0, axial direction Y, radial direction X, direction P of outer circumference. DETAILED DESCRIPTION

[0034] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments.

[0035] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be internal communication between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to the specific circumstances. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0036] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0037] Reference to "embodiment" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiment may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. The various embodiments in the present application may be combined with each other in the absence of conflict.

[0038] In the related art, the electrode assembly of the cylindrical secondary battery is a winding structure, and a tape is tied around the periphery of the electrode assembly to prevent the tail end of the winding structure from loosening. An insulating tape is wrapped around the circumferential corner of one end of the electrode assembly of the cylindrical secondary battery to insulate and protect the circumferential corner of one end of the winding structure. The problem caused by the above structure is that in the production and manufacturing of the cylindrical secondary battery, two process steps are required to assemble the tape and the insulating tape respectively, which makes the preparation process of the cylindrical secondary battery complicated and inconvenient for the production and manufacturing of the cylindrical secondary battery.

[0039] The main purpose of the embodiment of this scheme is to simplify the structure of the cylindrical secondary battery, and to insulate, protect and tighten the electrode assembly through a first insulating member, thereby simplifying the process steps of cylindrical secondary battery production and improving the production efficiency of cylindrical secondary batteries.

[0040] The present application has no particular restrictions on the shape of the cylindrical secondary battery, as long as the application purpose of the present application is achieved. In one or more embodiments, the cylindrical secondary battery is at least one of a cylindrical secondary battery, an elliptical cylindrical secondary battery, and a polygonal secondary battery (including a secondary battery with a regular polygonal cross-section or an irregular polygonal secondary battery).

[0041] In order to better understand the present application, the cylindrical secondary battery of the embodiment of the present application is described in detail below.

[0042] The dimensions of various components in the embodiments of the present application and the dimensions of the cylindrical secondary battery shown in the drawings are only exemplary and should not constitute any limitation to the present application.

[0043] Figure 1 A schematic diagram of the structure of a cylindrical secondary battery 100 provided in an embodiment of the present application is shown in FIG. Figure 1 As shown, in the first aspect, the embodiment of the present application provides a cylindrical secondary battery 100, and the axis of the cylindrical secondary battery 100 is L0. The radial direction of the cylindrical secondary battery 100 is X, and the axial direction of the cylindrical secondary battery 100 is Y, and Y is parallel to the axis L0 of the cylindrical secondary battery 100. The length of the cylindrical secondary battery 100 is L, and the diameter of the cylindrical secondary battery 100 is D.

[0044] In one or more embodiments, 17 mm ≤ D ≤ 75 mm, but is not limited thereto. For example, D may be 17 mm, 18 mm, 19 mm, 20 mm, 21 mm, 23 mm, 25 mm, 27 mm, 29 mm, 31 mm, 33 mm, 35 mm, 37 mm, 39 mm, 41 mm, 43 mm, 45 mm, 47 mm, 49 mm, 51 mm, 53 mm, 55 mm, 57 mm, 59 mm, 61 mm, 63 mm, 65 mm, 67 mm, 69 mm, 71 mm, 73 mm, 75 mm, or a range consisting of any two values ​​therebetween.

[0045] In one or more embodiments, 40 mm ≤ L ≤ 250 mm, but is not limited thereto. For example, L may be: 40 mm, 50 mm, 60 mm, 70 mm, 80 mm, 90 mm, 100 mm, 110 mm, 120 mm, 130 mm, 140 mm,

[0046] 150mm, 160mm, 170mm, 180mm, 190mm, 200mm, 210mm, 220mm, 230mm,

[0047] 240mm, 250mm or a range consisting of any two values ​​therebetween.

[0048] Figure 2 Schematic diagram of a cross-sectional structure of a cylindrical secondary battery 100 provided in an embodiment of the present application, Figure 3 This is a structural schematic diagram of a first insulating member 40 of a cylindrical secondary battery 100 provided in an embodiment of the present application. Figure 4 A cross-sectional structural diagram of a first insulating member 40 of a cylindrical secondary battery 100 provided in an embodiment of the present application is shown in FIG. Figure 2 , Figure 3 and Figure 4 As shown, the cylindrical secondary battery 100 includes a case 10 , a top cover 20 , an electrode assembly 30 and a first insulating member 40 .

[0049] The housing 10 has a housing opening 101; the top cover 20 is connected to the housing 10 and covers the housing opening 101; the electrode assembly 30 has a winding structure, the electrode assembly 30 is arranged in the housing 10, and the electrode assembly 30 has a first end surface 31 facing the top cover 20; the first insulating member 40 includes a first portion 41 and a second portion 42 connected to each other, the first portion 41 surrounds the outer peripheral surface 32 of the electrode assembly 30 for at least one circle, and the second portion 42 is arranged on the first end surface 31; along the axial direction Y of the cylindrical secondary battery, the electrode assembly 30 The length is L1, and the length of the first part 41 is L2. 0.5≤L2 / L1≤1, for example, L2 / L1 can be: 0.5, 0.52, 0.54, 0.56, 0.58, 0.6, 0.62, 0.64, 0.66, 0.68, 0.7, 0.72, 0.74, 0.76, 0.78, 0.8, 0.82, 0.84, 0.86, 0.88, 0.9, 0.92, 0.94, 0.96, 1 ​​or a range consisting of any two values ​​therebetween.

[0050] In the embodiment of the present application, in the preparation of the cylindrical secondary battery 100, the first portion 41 of the first insulating member 40 is wrapped around the outer peripheral surface 32 of the electrode assembly 30 for at least one circle to maintain the tightening and insulation of the winding structure, and the second portion 42 of the first insulating member 40 is made to extend beyond the first end surface 31 of the electrode assembly 30 to provide insulation protection for the first end surface 31 of the electrode assembly 30. Then, the second portion 42 is flattened on the first end surface 31 of the electrode assembly 30 by a flattening process.

[0051] Since the first part 41 and the second part 42 are connected to each other, that is, the end of the first part 41 and the end of the second part 42 are connected and directly connected, the first insulating member 40 is regarded as an integral component to provide insulation protection and tightening for the electrode assembly 30 at the same time. Compared with the conventional technical solution using tape and insulating tape, the embodiment of the present application is convenient for simplifying the structure of the cylindrical secondary battery and reducing the manufacturing process steps of the cylindrical secondary battery, thereby facilitating the production of the cylindrical secondary battery.

[0052] In one or more embodiments, 0.7≤L2 / L1≤1, for example, L2 / L1 can be: 0.7, 0.72, 0.74, 0.76, 0.78, 0.8, 0.82, 0.84, 0.86, 0.88, 0.9, 0.92, 0.94, 0.96, 1 ​​or a range consisting of any two values ​​therebetween. L2 / L1 adopts a larger ratio to improve the tightness of the first portion 41 around the electrode assembly 30 and keep the winding structure tight.

[0053] In one or more embodiments, 0.9≤L2 / L1≤1, for example, L2 / L1 can be: 0.9, 0.92, 0.94, 0.96, 1, or a range consisting of any two values ​​therebetween. L2 / L1 adopts a larger ratio to further improve the tightness of the first portion 41 around the electrode assembly 30 and maintain the tightening of the winding structure.

[0054] The present application has no particular restrictions on the size of the electrode assembly 30, as long as the purpose of the present application is met. In one or more embodiments, the radius of the electrode assembly 30 is R; 8mm≤R≤35mm, for example, R can be: 8mm, 9mm, 10mm, 11mm, 12mm, 13mm, 14mm, 15mm, 16mm, 17mm, 18mm, 19mm, 20mm, 21mm, 22mm, 23mm, 24mm, 25mm, 26mm, 27mm, 28mm, 29mm, 30mm, 31mm, 32mm, 33mm, 34mm, 35mm or a range consisting of any two values ​​therebetween, which is conducive to realizing a large-capacity cylindrical secondary battery.

[0055] In one or more embodiments, 35 mm ≤ L1 ≤ 240 mm, for example, L1 can be: 35 mm, 40 mm, 45 mm, 50 mm, 55 mm, 60 mm, 65 mm, 70 mm, 75 mm, 80 mm, 85 mm, 90 mm, 95 mm, 100 mm, 105 mm, 110 mm, 115 mm, 120 mm, 125 mm, 130 mm, 135 mm, 140 mm,

[0056] 145mm, 150mm, 155mm, 160mm, 165mm, 170mm, 175mm, 180mm, 185mm,

[0057] 190mm, 195mm, 200mm, 205mm, 210mm, 215mm, 220mm, 225mm, 230mm, 235mm, 240mm or a range consisting of any two values ​​therebetween is conducive to achieving a large-capacity cylindrical secondary battery 100 .

[0058] The present application has no particular limitation on the size of the first insulating member 40 , as long as the purpose of the present application is met.

[0059] In one or more embodiments, 17.5mm≤L2≤240mm. For example, L2 can be: 17.5mm, 18mm, 28mm, 38mm, 48mm, 58mm, 68mm, 78mm, 88mm, 98mm, 108mm, 118mm, 128mm, 138mm, 148mm, 158mm, 168mm, 178mm, 188mm, 198mm, 208mm, 218mm, 228mm, 238mm, 240mm or a range consisting of any two values ​​therebetween, which is conducive to realizing a large-capacity cylindrical secondary battery 100.

[0060] The width of the second portion 42 is L3 along the radial direction X of the cylindrical secondary battery 100. In one or more embodiments, 0.64 mm ≤ L3 ≤ 11.2 mm, for example, L3 may be: 0.64 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm, 5 mm, 5.5 mm, 6 mm, 6.5 mm, 7 mm, 7.5 mm, 8 mm, 8.5 mm, 9 mm, 9.5 mm, 10 mm, 10.5 mm, 11 mm, 11.2 mm, or a range consisting of any two values ​​therebetween.

[0061] Figure 5 A schematic structural diagram of a cylindrical secondary battery 100 provided in an embodiment of the present application, wherein the first insulating member 40 is in a flattened state, as shown in FIG. Figure 5 As shown, along the direction P around the outer circumference of the electrode assembly 30 , when the first insulating member 40 is flattened, the length of the first insulating member 40 is W1 .

[0062] In one or more embodiments, 51mm≤W1≤329.7mm. For example, W1 can be: 51mm, 55mm, 70mm, 85mm, 100mm, 115mm, 130mm, 145mm, 160mm, 175mm, 190mm, 205mm, 220mm, 235mm, 250mm, 265mm, 280mm, 295mm, 310mm, 329.7mm, or a range consisting of any two values ​​therebetween.

[0063] like Figure 3 and Figure 5As shown, in one or more embodiments, along the direction P around the outer circumference of the electrode assembly 30, the first insulating member 40 includes a starting section 43 and a tail section 44, and the tail section 44 has an overlapping area 45 with the starting section 43, and the width of the overlapping area 45 is W2, 1mm≤W2≤5mm, for example, W2 can be: 1mm, 1.2mm, 1.4mm, 1.6mm, 1.8mm, 2mm, 2.2mm, 2.4mm, 2.6mm, 2.8mm, 3mm, 3.2mm, 3.4mm, 3.6mm, 3.8mm, 4mm, 4.2mm, 4.4mm, 4.6mm, 4.8mm, 5mm or a range consisting of any two values ​​therebetween, so that the starting section 43 and the tail section 44 of the first insulating member 40 can be well overlapped, so that the first insulating member 40 is more firmly arranged on the electrode assembly 30.

[0064] In one or more embodiments, 1mm≤W2≤3mm. For example, W2 can be: 1mm, 1.2mm, 1.4mm, 1.6mm, 1.8mm, 2mm, 2.2mm, 2.4mm, 2.6mm, 2.8mm, 3mm or a range consisting of any two values ​​therebetween, which is beneficial to reducing the space occupied by the first insulating member 40 and improving the energy density of the cylindrical secondary battery 100.

[0065] In one or more embodiments, 0.08≤L3 / R≤0.32, for example, L3 / R can be: 0.08, 0.10, 0.12, 0.14, 0.16, 0.18, 0.20, 0.22, 0.24, 0.26, 0.28, 0.30, 0.32 or a range consisting of any two values ​​therebetween. On the one hand, it is beneficial for the second portion 42 to provide insulation protection around the first end face 31 of the electrode assembly 30; on the other hand, it is beneficial for reserving sufficient welding area for the first end face 31, so as to facilitate electrical connection between the first end face 31 and components such as the collector plate.

[0066] In one or more embodiments, 1<W1 / (2πR)≤1.5, π is 3.14, for example, W1 / (2πR) can be: 1.02, 1.04, 1.06, 1.08, 1.10, 1.12, 1.14, 1.16, 1.18, 1.20, 1.22, 1.24, 1.26, 1.28, 1.30, 1.32, 1.34, 1.36, 1.38, 1.40, 1.42, 1.44, 1.46, 1.48, 1.50 or a range consisting of any two values ​​therebetween, the first insulating member 40 surrounds the outer circumferential surface 32 of the electrode assembly 30 for more than one week, which is beneficial to the insulation protection and tightening of the electrode assembly 30.

[0067] In one or more embodiments, in a flattened state, the first insulating member 40 is substantially rectangular in shape, so that the first insulating member 40 is surrounded by the electrode assembly 30, wherein: Figure 5 The rectangle in FIG. 4 is only for illustration, and the first insulating member 40 is not limited to a strict rectangle, and its corners are not limited to right angles.

[0068] The first insulating member 40 is an integral structural member, so that the first insulating member 40 as a whole has good mechanical strength and the first insulating member 40 can be assembled through fewer process steps.

[0069] The present application has no particular limitation on the material of the first insulating member 40, as long as the purpose of the present application is met. In one or more embodiments, the material of the first insulating member 40 includes one of polyimide, polyethylene terephthalate, polypropylene or polyvinyl chloride, which has good insulation performance and mechanical strength, is conducive to providing insulation protection between the first end face 31 of the electrode assembly 30 and the shell 10, and is convenient for keeping the electrode assembly 30 tight.

[0070] Figure 6 for Figure 2 The enlarged view of A in the figure is as follows: Figure 6 As shown, in one or more embodiments, the shell 10 includes a side wall 11 and a bottom wall 12, the side wall 11 includes a recess 111, and the recess 111 is recessed into the shell 10; along the axial direction Y, the electrode assembly 30 is arranged between the bottom wall 12 and the recess 111; along the axial direction Y, the electrode assembly 30, the second part 42, and the recess 111 are arranged in sequence, and the projection of the recess 111 falls into the projection of the second part 42, the recess 111 is conducive to suppressing the movement of the electrode assembly 30, and the second part 42 is conducive to forming an insulating isolation between the first end face 31 of the electrode assembly 30 and the recess 111 of the shell 10.

[0071] In one or more embodiments, the electrode assembly 30 includes a first electrode plate, a second electrode plate and a diaphragm (the first electrode plate, the second electrode plate and the diaphragm are not shown); wherein, the first electrode plate has opposite polarity to the second electrode plate, the first electrode plate includes a first current collector and a first active material, in the first electrode plate, the first current collector includes a first main body area and a first empty foil area, the first active material is arranged in the first main body area, the first empty foil area includes a first flattened area, the first flattened area is away from the first main body area to form a first end face 31, the second part 42 insulates and isolates the first flattened area and the recess 111, the electrode assembly 30 is a full-ear structure, which is beneficial to reducing the internal resistance of the cylindrical secondary battery, and the second part 42 is beneficial to forming insulation isolation between the first flattened area of ​​the electrode assembly 30 and the recess 111 of the shell 10.

[0072] In the embodiments of the present application, in one or more embodiments of preparing the electrode assembly 30, the first electrode sheet, the diaphragm and the second electrode sheet are first stacked and wound to form a winding body, and then the first insulating member 40 is wound around the outer peripheral surface 32 of the winding body for at least one week, and the first empty foil area is gathered to bend the first empty foil area toward the inner direction of the winding body. Then, a flattening process is used to flatten the second part 42 and the first empty foil area together, and the first flattened area is away from the first main body area to form a first end face 31, and the winding body forms an electrode assembly 30 with a winding structure.

[0073] In one or more embodiments, the second pole piece includes a second current collector and a second active material. In the second pole piece, the second current collector includes a second main body area and a second hollow foil area. The second active material is arranged in the second main body area, and the second hollow foil area includes a second flattened area.

[0074] like Figure 2 As shown, in one or more embodiments, the top cover 20 includes an electrode terminal 21 and a current interrupt device 22 (Current Interrupt Device, abbreviated as CID), the current interrupt device 22 electrically connects the electrode terminal 21 and the first flattened area of ​​the first pole piece of the electrode assembly 30, the electrode terminal 21 is the first electrode of the cylindrical secondary battery 100, the shell 10 is electrically connected to the second flattened area of ​​the second pole piece of the electrode assembly 30, the shell 10 is the second electrode of the cylindrical secondary battery 100, and the polarities of the first electrode and the second electrode are opposite. When the air pressure in the shell 10 of the cylindrical secondary battery 100 is too high, the current interrupt device 22 disconnects the charge and discharge circuit of the electrode terminal 21 and the electrode assembly 30 to improve the safety of the cylindrical secondary battery 100.

[0075] In a second aspect, the present application provides a battery pack 200, Figure 7 is a schematic diagram of the structure of the battery pack 200 provided in the embodiment of the present application, such as Figure 7 As shown, the battery pack 200 includes the cylindrical secondary battery 100 of any of the above embodiments. There is at least one cylindrical secondary battery 100. In one or more embodiments, there are multiple cylindrical secondary batteries 100, and the multiple cylindrical secondary batteries 100 are connected in series or in parallel, or the multiple cylindrical secondary batteries 100 are combined in series and in parallel.

[0076] In a third aspect, the present application provides an electric device 300 , comprising the cylindrical secondary battery 100 or the battery pack 200 of any of the above embodiments.

[0077] In one or more embodiments, Figure 8 is a schematic diagram of the structure of the first electrical device provided in the embodiment of the present application, such as Figure 8As shown, the electric device 300 includes the battery pack 200 in the above embodiment, and the battery pack 200 includes the cylindrical secondary battery 100 in the above embodiment.

[0078] In one or more embodiments, Fig. 9 is a schematic diagram of the structure of a second electrical device provided in an embodiment of the present application, such as Fig. 9 As shown, the electric device 300 includes the cylindrical secondary battery 100 in the above embodiment.

[0079] The present application does not specifically limit the electrical device, and the electrical device includes electrical devices known in the prior art. For example, the electrical device includes but is not limited to computers, smart phones, backup power supplies, two-wheeled vehicles, drones, power tools or energy storage devices.

[0080] The above are only preferred embodiments of the present application and are not intended to limit the protection scope of the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application are included in the protection scope of the present application.

Claims

1. A cylindrical secondary battery, characterized in that: include: a housing having a housing opening; A top cover connected to the shell and covering the shell opening; an electrode assembly having a winding structure and disposed in the housing, wherein the electrode assembly has a first end surface facing the top cover; A first insulating member, comprising a first portion and a second portion connected to each other, wherein the first portion surrounds the outer circumference of the electrode assembly for at least one circle, and the second portion is disposed on the first end surface; Along the axial direction of the cylindrical secondary battery, the length of the electrode assembly is L1, and the length of the first portion is L2; 0.5≤L2 / L1≤1.

2. The cylindrical secondary battery according to claim 1, characterized in that: 0.7≤L2 / L1≤1.

3. The cylindrical secondary battery according to claim 2, characterized in that: 0.9≤L2 / L1≤1.

4. The cylindrical secondary battery according to any one of claims 1 to 3, characterized in that: The cylindrical secondary battery is a cylindrical secondary battery; The radius of the electrode assembly is R; Along the radial direction of the cylindrical secondary battery, the width of the second portion is L3; 0.08≤L3 / R≤0.

32.

5. The cylindrical secondary battery according to claim 4, characterized in that: 8mm≤R≤35mm.

6. The cylindrical secondary battery according to claim 4, characterized in that: Along the direction around the outer circumference of the electrode assembly, when the first insulating member is flattened, the length of the first insulating member is W1; 1<W1 / (2πR)≤1.

5.

7. The cylindrical secondary battery according to claim 6, characterized in that: Along the direction around the outer circumference of the electrode assembly, the first insulating member includes a starting section and a tail section, the tail section and the starting section have an overlapping area, and the width of the overlapping area is W2, 1mm≤W2≤5mm.

8. The cylindrical secondary battery according to claim 7, characterized in that: 1mm≤W2≤3mm.

9. The cylindrical secondary battery according to claim 1, characterized in that: The shell comprises a side wall and a bottom wall, the side wall comprises a recessed portion, and the recessed portion is recessed into the shell; Along the axial direction, the electrode assembly is disposed between the bottom wall and the recess; Along the axial direction, the electrode assembly, the second part, and the recess are arranged in sequence, and the projection of the recess falls within the projection of the second part.

10. The cylindrical secondary battery according to claim 9, characterized in that: The electrode assembly includes a first electrode sheet, a second electrode sheet and a diaphragm; wherein, The first pole piece has opposite polarity to the second pole piece. The first pole piece includes a first current collector and a first active material. The first current collector includes a first main body area and a first empty foil area. The first active material is arranged in the first main body area. The first empty foil area includes a first flattened area. The first flattened area is away from the first main body area to form the first end face. The second part insulates and isolates the first flattened area from the recess.

11. The cylindrical secondary battery according to claim 1, characterized in that: The material of the first insulating member includes one of polyimide, polyethylene terephthalate, polypropylene or polyvinyl chloride.

12. The cylindrical secondary battery according to claim 1, characterized in that: The first insulating member is an integral structural member.

13. A battery pack, characterized in that: A cylindrical secondary battery comprising any one of claims 1 to 12.

14. An electrical device, characterized in that: The invention comprises the cylindrical secondary battery according to any one of claims 1 to 12 or the battery pack according to claim 13.

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