Cylindrical battery, battery pack and power utilization device

Abstract

The invention provides a cylindrical battery, a battery pack and a power utilization device, the cylindrical battery comprises a shell and a top cover assembly, the top cover assembly is in insulation connection with the shell, the top cover assembly comprises a top cover and an anti-explosion sheet, and the top cover and the anti-explosion sheet are arranged along the axial direction of the cylindrical battery; the explosion-proof piece comprises a fixed part and an overturning part, the fixed part is connected with the top cover, the overturning part comprises an electric connection area and a thinning area, the electric connection area, the thinning area and the fixed part are sequentially arranged in the radial direction of the cylindrical battery when being observed in the axial direction, and the notch groove is formed in the thinning area. When the internal air pressure of the cylindrical battery rises to reach the first threshold value, and the overturning part is overturned and deformed towards the top cover, the thickness of the thinned area is relatively thin, and the bending angle of the thinned area is increased, so that the overturned overturning part is relatively flat, and the overturning height of the overturning part is favorably reduced. And in the design of the cylindrical battery, the distance between the top cover and the overturning part is favorably reduced, and the energy density of the cylindrical battery is improved.

Description

Technical Field

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

[0002] Due to the mature manufacturing process and stable product quality of cylindrical batteries, their market penetration rate is very high. The explosion-proof plate is an important safety protection structure of cylindrical batteries. When the pressure inside the cylindrical battery reaches the threshold, the explosion-proof plate flips over to cut off the power and explode to release the pressure to ensure safe use.

[0003] In the prior art, since the explosion-proof piece needs to be turned over at a relatively high height when it is powered off and exploded, the overall height of the cylindrical battery is relatively large, which affects the volume energy density of the cylindrical battery. Summary of the invention

[0004] The purpose of the embodiments of the present application is to provide a cylindrical battery, a battery pack and an electrical device, which is conducive to reducing the flip height of the explosion-proof plate during power failure and explosion, reducing the overall height of the cylindrical battery, and improving the volume energy density of the cylindrical battery. The specific technical solution is as follows:

[0005] The first aspect of the present application provides a cylindrical battery, comprising: a shell; a top cover assembly, insulated and connected to the shell, the top cover assembly comprising a top cover and an explosion-proof plate, the top cover and the explosion-proof plate are arranged along the axial direction of the cylindrical battery; the explosion-proof plate comprises a fixed part and a flip part, the fixed part is connected to the top cover, the flip part comprises an electrical connection area and a thinning area, and when viewed along the axial direction, the electrical connection area, the thinning area and the fixed part are arranged in sequence along the radial direction of the cylindrical battery; a groove is arranged in the thinning area.

[0006] When the internal air pressure of the cylindrical battery rises to the first threshold value, causing the flip part to flip toward the top cover and deform, the thinned area is thinner, and the bending angle of the thinned area increases, making the flipped flip part more "flat", which is conducive to reducing the flip height of the flip part. In the design of cylindrical batteries, it is beneficial to reduce the distance between the top cover and the flip part to improve the energy density of the cylindrical battery.

[0007] In one or more embodiments, the projection of the flip portion is circular along the axial direction, and the radius of the projection of the flip portion is R1; along the radial direction, the width of the thinned area is W1; 0.15≦W1 / R1≦0.29, W1 and R1 have the same unit. Within the W1 / R1 ratio range, it is beneficial for the thinned area to bend at a larger angle after the flip portion is deformed toward the top cover, so that the flipped flip portion is more "flattened", which is beneficial to further reduce the flip height of the flip portion. In the design of cylindrical batteries, it is beneficial to further reduce the distance between the top cover and the flip portion to improve the energy density of the cylindrical battery.

[0008] In one or more embodiments, 0.15≦W1 / R1≦0.2. Within the W1 / R1 ratio range, after the flip part is flipped and deformed toward the top cover, the thinned area is bent at a larger angle, so that the flip part is further "flattened", which is conducive to further reducing the flip height of the flip part. In the design of cylindrical batteries, it is conducive to further reducing the distance between the top cover and the flip part to improve the energy density of the cylindrical battery.

[0009] In one or more embodiments, the radius of the cylindrical battery is R2, 1 / 3≦R1 / R2≦2 / 3. Within the R1 / R2 ratio range, the stable flipping of the flip part and the rapid pressure release after the groove is opened are facilitated.

[0010] In one or more embodiments, 15 mm≦R2≦50 mm. Within the R2 range, the capacity of the cylindrical battery is improved.

[0011] In one or more embodiments, 7.5 mm≦R1≦25 mm. Within the range of R1, when the internal air pressure of the cylindrical battery rises to reach the first threshold, it is conducive to the rapid and stable flipping of the flipping part.

[0012] In one or more embodiments, radially, the thinned area includes a first end close to the axis of the cylindrical battery and a second end away from the axis of the cylindrical battery; radially, the distance between the second end and the fixed portion is L1; 0mm≦L1≦0.2mm. Within the L1 range, the thinned area is closer to the fixed portion, which is conducive to a larger bending angle of the thinned area, so that the flipped flip portion is further "flattened", thereby facilitating further reducing the flip height of the flip portion. In the design of cylindrical batteries, it is beneficial to further reduce the distance between the top cover and the flip portion to improve the energy density of the cylindrical battery.

[0013] In one or more embodiments, the distance between the groove and the first end is W2, 2 / 5≦W2 / W1≦3 / 5, and W1 and W2 have the same unit. When the internal pressure of the cylindrical battery rises to a second threshold, the groove bursts and breaks open, and the cylindrical battery exhausts and releases pressure to the outside through the broken groove. Within the range of W2 / W1, the groove is easy to process, which is beneficial to improving the yield rate of cylindrical batteries.

[0014] In one or more embodiments, the thinned area is a closed ring; the groove extends around the axis of the cylindrical battery, and the groove is an open ring. When the internal air pressure of the cylindrical battery rises to a second threshold, the groove bursts open. Since the groove is an open ring, the two ends of the groove are not connected, so the part inside the groove will not be completely separated from the part outside the groove, which is conducive to reducing the residue splashed to the outside of the cylindrical battery.

[0015] In one or more embodiments, the electrical connection area includes a curved section and a straight section, and the curved section is curved away from the top cover; when viewed axially, the projection of the straight section surrounds the projection of the curved section, and the straight section connects the curved section and the thinned area; along the axial direction, the thickness of the straight section is T1, and the thickness of the thinned area is T2, 1 / 2≦T2 / T1≦4 / 5, and T1 and T2 have the same unit. Within the range of T2 / T1, compared with the straight section, the thinned area is conducive to a larger bending angle, so that the flipping part of the flip is further "flattened", which is conducive to further reducing the flip height of the flip part. In the design of cylindrical batteries, it is conducive to further reducing the distance between the top cover and the flipping part to improve the energy density of the cylindrical battery.

[0016] In one or more embodiments, 1 / 2≦T2 / T1≦3 / 5. The flip part of the cylindrical battery is more "flattened" after flipping, which is conducive to reducing the flip height of the flip part and the distance between the electrical connection area of ​​the flip part and the top cover. In the design of cylindrical batteries, it is conducive to reducing the distance between the top cover and the flip part and improving the energy density of the cylindrical battery.

[0017] In one or more embodiments, 0.2 mm≦T2≦0.4 mm. Within the range of T2, the thinned area is advantageously provided with good strength, so that the thinned area of ​​the cylindrical battery is not prone to unexpected fracture under normal operating conditions.

[0018] In one or more embodiments, the groove bottom thickness along the axial direction is T3, 0.1mm≦T3≦0.2mm. Within the range of T3, when the internal air pressure of the cylindrical battery rises to the second threshold, the groove is easy to break quickly, reducing the pressure release time of the cylindrical battery and improving the safety of the cylindrical battery.

[0019] In one or more embodiments, the material of the burst disk includes aluminum.

[0020] In one or more embodiments, along the axial direction, the flip portion is thinned toward one side of the top cover to form a thinned area.

[0021] A second aspect of the present application provides a battery pack comprising a cylindrical battery in any of the above embodiments.

[0022] A third aspect of the present application provides an electrical device comprising a cylindrical battery or a battery pack according to any of the above embodiments.

[0023] The cylindrical battery, battery pack and electrical device provided in the embodiment of the present application, the cylindrical battery includes a shell and a top cover assembly, the top cover assembly is insulated and connected to the shell, the top cover assembly includes a top cover and an explosion-proof plate, the top cover and the explosion-proof plate are arranged along the axial direction of the cylindrical battery; the explosion-proof plate includes a fixed part and a flip part, the fixed part is connected to the top cover, the flip part includes an electrical connection area and a thinning area, and when viewed along the axial direction, the electrical connection area, the thinning area and the fixed part are arranged in sequence along the radial direction of the cylindrical battery, and the groove is arranged in the thinning area. When the internal air pressure of the cylindrical battery rises to reach the first threshold value, the flip part flips and deforms toward the top cover. Due to the thin thickness of the thinning area, the bending angle of the thinning area increases, making the flip part of the flipping more "flat", which is conducive to reducing the flip height of the flip part. In the design of cylindrical batteries, it is beneficial to reduce the spacing between the top cover and the flip part to improve the energy density of the cylindrical battery.

[0024] Of course, any product implementing the present application does not necessarily need to achieve all of the above advantages at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] 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.

[0026] Figure 1 A schematic diagram of the structure of a cylindrical battery according to an embodiment of the present application;

[0027] Figure 2 for Figure 1 A schematic diagram of a partial cross-sectional structure of a cylindrical battery shown;

[0028] Figure 3 for Figure 2 A magnified view of middle;

[0029] Figure 4 for Figure 1 A schematic diagram of the top view of the explosion-proof plate in the cylindrical battery shown;

[0030] Figure 5 for Figure 1 A schematic cross-sectional view of the explosion-proof disk in the cylindrical battery shown;

[0031] Figure 6 for Figure 5 Enlarged view of middle B;

[0032] Figure 7 A schematic diagram of a partial cross-sectional structure of a cylindrical battery according to another embodiment of the present application;

[0033] Figure 8 A schematic diagram of the structure of a battery pack provided in an embodiment of the present application;

[0034] Fig. 9 A schematic diagram of the structure of a first electrical device provided in an embodiment of the present application;

[0035] Fig.10 A schematic diagram of the structure of a second electrical device provided in an embodiment of the present application.

[0036] The reference numerals are as follows:

[0037] Shell 10, top cover assembly 20, top cover 21, end surface 211, explosion-proof disk 22, fixing portion 221, flip portion 222, electrical connection area 2221, curved section 22211, straight section 22212, thinned area 2222, first end 2222a, second end 2222b, notch 223, connecting plate 23, electrode assembly 30, cylindrical battery 100, battery pack 200, electrical device 300;

[0038] Radial direction X, axial direction Y, axis line L0. DETAILED DESCRIPTION

[0039] 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.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] In the related art, the explosion-proof disc is directly pressed from a plate with uniform thickness. As the diameter of cylindrical batteries increases, the diameter of the explosion-proof disc also increases in large-diameter cylindrical batteries, and the height required for its flipping is relatively large. Therefore, a large axial space needs to be reserved on the inner side of the top cover of the cylindrical battery to meet the flipping needs of the explosion-proof disc. This structural design easily affects the volume energy density of the cylindrical battery.

[0044] The present application provides a cylindrical battery, a battery pack and an electrical device, the main purpose of which is to increase the volume energy density of the cylindrical battery.

[0045] Figure 1 A schematic diagram of the structure of a cylindrical battery according to 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 battery 100, which can be a nickel-hydrogen battery, a nickel-cadmium battery, a lead-acid (or lead storage) battery, a lithium-ion battery, a polymer lithium-ion battery, a sodium-ion battery, a magnesium-ion battery, etc. The axis of the cylindrical battery 100 is L0. The radial direction of the cylindrical battery 100 is X, and X is in a plane perpendicular to the axis L0, which is the direction from the axis L0 to the outside of the cylindrical battery 100. The axial direction of the cylindrical battery 100 is Y, and Y is parallel to the axis L0 of the cylindrical battery 100.

[0046] Along the radial direction X of the cylindrical battery 100, the radius of the cylindrical battery is R2. In one or more embodiments, 15mm≦R2≦50mm. But not limited to this. For example, R2 can be: 15mm, 16mm, 18mm, 20mm, 22mm, 24mm, 26mm, 28mm, 30mm, 32mm, 34mm, 36mm, 38mm, 40mm, 42mm, 44mm, 46mm, 48mm, 50mm, or a value between any two values. Within the R2 range, it is beneficial to increase the capacity of the cylindrical battery.

[0047] Along the axial direction Y of the cylindrical battery 100, the length of the cylindrical battery is L. In one or more embodiments, 40 mm≦L≦250 mm. But not limited thereto. For example, L can be: 40 mm, 50 mm, 60 mm, 70 mm, 80 mm, 90 mm, 100 mm, 110 mm, 120 mm, 130 mm, 140 mm, 150 mm, 160 mm, 170 mm, 180 mm, 190 mm, 200 mm, 210 mm, 220 mm, 230 mm, 240 mm, 250 mm, or a value between any two values.

[0048] Figure 2 for Figure 1 The schematic diagram of the partial cross-sectional structure of the cylindrical battery shown in FIG. Figure 3 for Figure 2 The enlarged view of A in the figure is as follows: Figure 2 and Figure 3 As shown, the cylindrical battery 100 includes: a shell 10 and a top cover assembly 20, the top cover assembly 20 is insulated and connected to the shell 10, the top cover assembly 20 includes a top cover 21 and an explosion-proof plate 22, the top cover 21 and the explosion-proof plate 22 are arranged along the axial direction Y of the cylindrical battery 100; the explosion-proof plate 22 includes a fixing portion 221 and a flipping portion 222, the fixing portion 221 is connected to the top cover 21, the flipping portion 222 includes an electrical connection area 2221 and a thinning area 2222, and when observed along the axial direction Y of the cylindrical battery 100, the electrical connection area 2221, the thinning area 2222 and the fixing portion 221 are sequentially arranged along the radial direction X of the cylindrical battery 100; the thinning area 2222 is provided with a groove 223.

[0049] When the internal air pressure of the cylindrical battery 100 rises to the first threshold value P1, the flip part 222 flips toward the top cover 21 and deforms. Since the thickness of the thinned area 2222 is thin, the bending angle of the thinned area 2222 increases, making the flipped flip part 222 more "flat", which is conducive to reducing the flip height of the flip part 222. In the design of the cylindrical battery 100, it is conducive to reducing the distance between the top cover 21 and the flip part 222, so as to improve the energy density of the cylindrical battery 100.

[0050] In one or more embodiments, 1.1 MPa≤P1≤1.3 MPa, but not limited thereto. For example, P1 may be: 1.10 MPa, 1.12 MPa, 1.14 MPa, 1.16 MPa, 1.18 MPa, 1.20 MPa, 1.22 MPa, 1.24 MPa, 1.26 MPa, 1.28 MPa, 1.30 MPa, or a value between any two values.

[0051] In one or more embodiments, the top cover assembly 20 includes a connecting plate 23, the connecting plate 23 connects the flip part 222 of the explosion-proof disc 22 and the electrode assembly 30, and after the flip part 222 flips and deforms toward the top cover 21, the part of the flip part 222 carrying the connecting plate 23 is separated from the connecting plate 23, so that the connecting plate 23 and the explosion-proof disc 22 are disconnected. This is beneficial to improve the safety of the cylindrical battery 100.

[0052] In one or more embodiments, Figure 3 As shown, along the axial direction Y, the projection of the flip portion 222 is circular, and the radius of the projection of the flip portion 222 is R1; along the radial direction X, the width of the thinned area 2222 is W1; 0.15≦W1 / R1≦0.29, but not limited thereto. For example, W1 / R1 can be: 0.15, 0.16, 0.17, 0.18, 0.19, 0.20, 0.21, 0.22, 0.23, 0.24, 0.25, 0.26, 0.27, 0.28, 0.29, or a value between any two values. Within the W1 / R1 ratio range, it is beneficial for the flip portion 222 to bend at a larger angle after the flip portion 222 is flipped and deformed toward the top cover 21, so that the flipped flip portion 222 is more "flattened", which is beneficial to further reduce the flip height of the flip portion 222. In the design of the cylindrical battery 100 , it is beneficial to further reduce the distance between the top cover 21 and the flip portion 222 to improve the energy density of the cylindrical battery 100 .

[0053] In one or more embodiments, 0.15≦W1 / R1≦0.2. Within the W1 / R1 ratio range, after the flip part is flipped and deformed toward the top cover, the thinned area is bent at a larger angle, so that the flip part is further "flattened", which is conducive to further reducing the flip height of the flip part. In the design of cylindrical batteries, it is conducive to further reducing the distance between the top cover and the flip part to improve the energy density of the cylindrical battery.

[0054] In one or more embodiments, 1.125 mm≦W1≦7.5 mm, but not limited thereto. For example, R1 may be: 1.125 mm, 1.3 mm, 1.5 mm, 1.7 mm, 1.9 mm, 2.1 mm, 2.3 mm, 2.5 mm, 2.7 mm, 2.9 mm, 3.1 mm, 3.3 mm, 3.5 mm, 3.7 mm, 3.9 mm, 4.1 mm, 4.3 mm, 4.5 mm, 4.7 mm, 4.9 mm, 5.1 mm, 5.3 mm, 5.5 mm, 5.7 mm, 5.9 mm, 6.1 mm, 6.3 mm, 6.5 mm, 6.7 mm, 6.9 mm, 7.1 mm, 7.3 mm, 7.5 mm, or a value between any two values. In the R1 range, when the internal air pressure of the cylindrical battery 100 rises to the first threshold, the thinned area 2222 bends at a larger angle, making the flipped flip portion 222 more "flattened", thereby facilitating further reducing the flipping distance of the flip portion 222. In the design of the cylindrical battery 100, it is beneficial to further reduce the distance between the top cover 21 and the flip portion 222, so as to improve the energy density of the cylindrical battery 100.

[0055] In one or more embodiments, 5mm≦R1≦33mm, but not limited thereto. For example, R1 may be: 5mm, 6mm, 7mm, 7.5mm, 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, or a value between any two values. Within the R1 range, when the internal air pressure of the cylindrical battery 100 rises to the first threshold, it is conducive to the rapid and stable flipping of the flipping portion 222.

[0056] In one or more embodiments, 7.5 mm≦R1≦25 mm. Within the R1 range, R1 ≥ 7.5 mm is conducive to increasing the radial width of the groove 223, thereby improving the pressure relief efficiency of the cylindrical battery 100 and further improving the safety of the cylindrical battery 100; R1 ≤ 25 mm is conducive to reducing the size of the explosion-proof plate 22 and reducing the turning height of the turning portion 222.

[0057] In one or more embodiments, the radius of the cylindrical battery 100 is R2, 1 / 3≦R1 / R2≦2 / 3, but not limited thereto. For example, R1 / R2 can be: 10 / 30, 11 / 30, 12 / 30, 13 / 30, 14 / 30, 15 / 30, 16 / 30, 17 / 30, 18 / 30, 19 / 30, 20 / 30, or a value between any two values. Within the R1 / R2 ratio range, the stable flipping of the flip portion 222 and the rapid pressure relief after the groove 223 is opened are facilitated.

[0058] In one or more embodiments, along the radial direction X, the thinned region 2222 includes a first end 2222a close to the axis L0 of the cylindrical battery 100 and a second end 2222b away from the axis L0 of the cylindrical battery 100;

[0059] The distance between the groove 223 and the first end 2222a is W2, 2 / 5≦W2 / W1≦3 / 5, but not limited thereto. For example, W2 / W1 can be: 40 / 100, 41 / 100, 42 / 100, 43 / 100, 44 / 100, 45 / 100, 46 / 100, 47 / 100, 48 / 100, 49 / 100, 50 / 100, 51 / 100, 52 / 100, 53 / 100, 54 / 100, 55 / 100, 56 / 100, 57 / 100, 58 / 100, 59 / 100, 60 / 100, or a value between any two values. When the internal pressure of the cylindrical battery 100 rises to the second threshold value P2, the groove 223 is broken, and the cylindrical battery 100 releases pressure to the outside through the broken groove 223. Within the range of W2 / W1, the groove 223 is easy to process, which is beneficial to improve the yield of the cylindrical battery 100.

[0060] In one or more embodiments, 1.9 MPa≤P2≤2.1 MPa, but not limited thereto. For example, P2 may be: 1.90 MPa, 1.92 MPa, 1.94 MPa, 1.96 MPa, 1.98 MPa, 2.00 MPa, 2.02 MPa, 2.04 MPa, 2.06 MPa, 2.08 MPa, 2.10 MPa, or a value between any two values.

[0061] In one or more embodiments, along the axial direction Y, the flip portion 222 is thinned toward one side of the top cover 21 to form a thinned area 2222 .

[0062] The present application has no particular limitation on the shape of the thinned region 2222 . Figure 4 for Figure 1 The schematic diagram of the top view of the explosion-proof plate 22 in the cylindrical battery 100 is shown in FIG. Figure 4As shown, in one or more embodiments, the thinned area 2222 is a closed ring; the groove 223 extends around the axis L0 of the cylindrical battery 100, and the groove 223 is an open ring. When the internal air pressure of the cylindrical battery 100 rises to reach the second threshold, the groove 223 explodes and breaks open. Since the groove 223 is an open ring, the two ends of the groove are not connected. Therefore, the part inside the groove 223 of the explosion-proof plate 22 will not be completely separated from the part outside the groove 223, which is conducive to reducing the residue splashed to the outside of the cylindrical battery 100.

[0063] Figure 5 for Figure 1 The cross-sectional structure diagram of the explosion-proof plate 22 in the cylindrical battery 100 is shown in FIG. Figure 6 for Figure 5 The enlarged view of B is shown in Figure 5 and Figure 6 As shown, in one or more embodiments, the electrical connection area 2221 includes a curved segment 22211 and a straight segment 22212, and the curved segment 22211 is curved away from the top cover 21; observed along the axial direction Y, the projection of the straight segment 22212 surrounds the projection of the curved segment 22211, and the straight segment 22212 connects the curved segment 22211 and the thinned area 2222; along the axial direction Y, the thickness of the straight segment 22212 is T1, and the thickness of the thinned area 2222 is T2, 1 / 2≦T2 / T1≦4 / 5, but is not limited to this. For example, T2 / T1 may be: 0.50, 0.51, 0.52, 0.53, 0.54, 0.55, 0.56, 0.57, 0.58, 0.59, 0.60, 0.61, 0.62, 0.63, 0.64, 0.65, 0.66, 0.67, 0.68, 0.69, 0.70, 0.71, 0.72, 0.73, 0.74, 0.75, 0.76, 0.77, 0.78, 0.79, 0.80, or a value between any two values. Within the range of T2 / T1, compared with the straight section 22212, the thinning area 2222 is advantageously bent at a larger angle, so that the flipped flip portion 222 is further "flattened", thereby facilitating further reducing the flip height of the flip portion 222. In the design of the cylindrical battery 100 , it is beneficial to further reduce the distance between the top cover 21 and the flip portion 222 to improve the energy density of the cylindrical battery 100 .

[0064] In one or more embodiments, 1 / 2≦T2 / T1≦3 / 5. The flip portion 222 of the cylindrical battery 100 is more "flattened" after flipping, which is helpful to reduce the flip height of the flip portion 222 and the distance between the electrical connection area 2221 of the flip portion 222 and the top cover 21. In the design of the cylindrical battery 100, it is helpful to reduce the distance between the top cover 21 and the flip portion 222 and improve the energy density of the cylindrical battery 100.

[0065] In one or more embodiments, 0.4 mm≦T1≦0.8 mm, but is not limited thereto. For example, T1 may be: 0.40 mm, 0.42 mm, 0.44 mm, 0.46 mm, 0.48 mm, 0.50 mm, 0.52 mm, 0.54 mm, 0.56 mm, 0.58 mm, 0.60 mm, 0.62 mm, 0.64 mm, 0.66 mm, 0.68 mm, 0.70 mm, 0.72 mm, 0.74 mm, 0.76 mm, 0.78 mm, 0.80 mm, or a value between any two values.

[0066] In one or more embodiments, 0.2mm≦T2≦0.4mm, but not limited thereto. For example, T2 may be: 0.20mm, 0.22mm, 0.24mm, 0.26mm, 0.28mm, 0.30mm, 0.31mm, 0.32mm, 0.33mm, 0.34mm, 0.35mm, 0.36mm, 0.37mm, 0.38mm, 0.39mm, 0.40mm, or a value between any two values. Within the range of T2, it is beneficial for the thinning area 2222 to have good strength, so that the cylindrical battery 100 is not prone to unexpected fracture in the thinning area 2222 under normal operating conditions.

[0067] In one or more embodiments, along the axial direction Y, the groove bottom thickness of the groove 223 is T3, 0.1mm≦T3≦0.2mm, but not limited thereto. For example, T3 may be: 0.100mm, 0.105mm, 0.110mm, 0.115mm, 0.120mm, 0.125mm, 0.130mm, 0.135mm, 0.140mm, 0.145mm, 0.150mm, 0.155mm, 0.160mm, 0.165mm, 0.170mm, 0.175mm, 0.180mm, 0.185mm, 0.190mm, 0.195mm, 0.200mm, or a value between any two values. In the range of T3, when the internal gas pressure of the cylindrical battery 100 rises to reach the second threshold, the notch 223 is easy to break quickly, which reduces the pressure release time of the cylindrical battery 100 and improves the safety of the cylindrical battery 100.

[0068] In one or more embodiments, the material of the explosion-proof disk 22 includes aluminum. Aluminum does not easily react chemically with lithium ions, and thus is easily applicable to the cylindrical battery 100 of lithium ions.

[0069] Figure 7 FIG. 1 is a schematic diagram of a partial cross-sectional structure of a cylindrical battery 100 according to another embodiment of the present application, as shown in FIG. Figure 7As shown, in one or more embodiments, along the radial direction X, the distance between the second end 2222b and the fixing portion 221 is L1; 0mm≦L1≦0.2mm, but not limited thereto. For example, L1 can be: 0mm, 0.01mm, 0.02mm, 0.03mm, 0.04mm, 0.05mm, 0.06mm, 0.07mm, 0.08mm, 0.09mm, 0.10mm, 0.11mm, 0.12mm, 0.13mm, 0.14mm, 0.15mm, 0.16mm, 0.17mm, 0.18mm, 0.19mm, 0.20mm, or a value between any two values. In the L1 range, the thinned area 2222 is closer to the fixed portion 221, which is conducive to the thinned area 2222 bending at a larger angle, so that the flipped flip portion 222 is further "flattened", thereby facilitating further reducing the flip height of the flip portion 222. In the design of the cylindrical battery 100, it is conducive to further reducing the distance between the top cover 21 and the flip portion 222, so as to improve the energy density of the cylindrical battery 100.

[0070] like Figure 2 As shown, in one or more embodiments, the polarity of the housing 10 and the top cover 21 are different. The top cover 21 serves as the negative electrode of the cylindrical battery 100, and the housing 10 serves as the positive electrode of the cylindrical battery 100, which can omit the traditional positive electrode terminal, which is beneficial to simplify the structure of the cylindrical battery 100 and improve the energy density of the cylindrical battery 100.

[0071] In one or more embodiments, the top cover 21 serves as the positive electrode of the cylindrical battery 100 , and the shell 10 serves as the negative electrode of the cylindrical battery 100 , which can omit the traditional negative electrode terminal, thereby simplifying the structure of the cylindrical battery 100 and improving the energy density of the cylindrical battery 100 .

[0072] The cylindrical battery 100 of the present application is not limited to being a primary battery or a secondary battery. As an example, the cylindrical battery is a lithium-ion secondary battery. In one or more embodiments, the electrode assembly 30 includes a first pole piece, a second pole piece, and a diaphragm. The first pole piece and the second pole piece have opposite polarities, and the diaphragm is disposed between the first pole piece and the second pole piece. During the charge and discharge process of the lithium-ion secondary battery, lithium ions are inserted and removed back and forth between the first pole piece and the second pole piece.

[0073] In one or more embodiments, the first pole piece includes a first body and a first pole ear, and the second pole piece includes a second body and a second pole ear. The first body includes a first current collector and a first active material layer coated on the surface of the first current collector, and the first pole ear is connected to the first current collector. The second body includes a second current collector and a second active material layer coated on the surface of the second current collector, and the second pole ear is connected to the second current collector. The top cover 21 is electrically connected to the first pole ear of the electrode assembly 30, and the top cover 21 forms the first electrode terminal of the cylindrical battery 100. The shell 10 is electrically connected to the second pole ear of the electrode assembly 30, and the shell 10 forms the second electrode terminal of the cylindrical battery 100. One of the first electrode terminal and the second electrode terminal is a positive electrode, and the other is a negative electrode. As a result, the shell 10 replaces one of the traditional electrode terminals, which is conducive to simplifying the structure of the cylindrical battery 100.

[0074] In a second aspect, the present application provides a battery pack 200, Figure 8 A schematic diagram of the structure of the battery pack provided in the embodiment of the present application, such as Figure 8 As shown, the battery pack 200 includes the cylindrical battery 100 of any of the above embodiments. There is at least one cylindrical battery 100. In one or more embodiments, there are multiple cylindrical batteries 100, and the multiple cylindrical batteries 100 are connected in series or in parallel, or the multiple cylindrical batteries 100 are combined in series and in parallel.

[0075] In a third aspect, the present application provides an electrical device 300, comprising a cylindrical battery 100 or a battery pack 200 according to any of the above embodiments.

[0076] In one or more embodiments, Fig. 9 A schematic diagram of the structure of the first electrical device provided in the embodiment of the present application is shown in FIG. Fig. 9 As shown, the electric device 300 includes the battery pack 200 in the above embodiment, and the battery pack 200 includes the cylindrical battery 100 in the above embodiment.

[0077] In one or more embodiments, Fig.10 A schematic diagram of the structure of a second electrical device provided in an embodiment of the present application is shown in FIG. Fig.10 As shown, the electric device 300 includes the cylindrical battery 100 in the above embodiment.

[0078] 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 a backup power supply, a two-wheeled vehicle, an unmanned aerial vehicle, a power tool, or an energy storage device.

[0079] Test method for the overturn height of explosion-proof disk:

[0080] The end surface 211 of the top cover 21 is cut off, and the height change of the center of the flip part 222 of the explosion-proof plate 22 of the cylindrical battery before and after the explosion test is measured by a height gauge (Mitutoyo height gauge 192-631-10 (standard type)), to obtain the flip height δ of the explosion-proof plate 22.

[0081] Preparation and testing of the battery cells of each embodiment and comparative example:

[0082] Preparation of cylindrical batteries: groove the empty steel shell according to the production line process, insert the top cover assembly, and seal the shell to obtain a cylindrical battery. Use drilling equipment to drill a circular hole at the bottom of the cylindrical battery shell. The diameter of the circular hole is 5mm. The explosion design value (i.e., the second threshold) of the explosion-proof disk of the top cover assembly is 2MPa.

[0083] Fixture fixation: Use a fixture (self-made) to fix the cylindrical battery and compress the sealing ring that contacts the bottom of the cylindrical battery shell to seal;

[0084] Explosion test: Use a pneumatic burst tester (model SC-QYBP-10, Xiamen Sanchuang Keyi Testing Equipment Co., Ltd.), open the inflation valve, and inflate the inside of the shell through the circular hole at the bottom of the shell at a speed of 0.1Mpa / s. Maintain the pressure after reaching 1.8Mpa, and end the test after maintaining the pressure for 10 minutes.

[0085] Embodiment 1:

[0086] The flipping part of the cylindrical battery explosion-proof piece is provided with an electrical connection area and a thinning area. The specific preparation parameters of D, L, R2, R1, W1, L1, W2, T2, T1, and T3 of the cylindrical battery are shown in Table 1.

[0087] Embodiment 2 to embodiment 7:

[0088] Except for adjusting the relevant preparation parameters according to Table 1, the rest is the same as Example 1.

[0089] Comparative Example 1

[0090] The flipping portion of the cylindrical battery explosion-proof plate is not provided with a thinning area. The specific preparation parameters of D, L, R2, R1, W1, T1, and T3 of the cylindrical battery are the same as those in Example 1 except that they are adjusted according to Table 1.

[0091] The parameters and performance of each embodiment and comparative example of the present application are described below. The parameters and performance of each embodiment and comparative example are shown in Table 1.

[0092] Table 1

[0093]

[0094] The annotations for the parameters in Table 1 are as follows:

[0095] D is the diameter of the cylindrical battery, in mm;

[0096] L is the length of the cylindrical battery, in mm;

[0097] R2 is the radius of the cylindrical battery, in mm;

[0098] R1 is the radius of the projection of the axial turning portion, in mm;

[0099] W1 is the radial width of the thinning area, in mm;

[0100] L1 is the distance between the second end of the thinned area and the fixing portion in the radial direction, in mm;

[0101] W2 is the distance from the groove to the first end of the thinning area, in mm;

[0102] T2 is the thickness of the thinned area, in mm;

[0103] T1 is the thickness of the straight section, in mm;

[0104] T3 is the groove bottom thickness, in mm;

[0105] δ is the deformation size of the top cover before and after the 1.8Mpa explosion test, in mm.

[0106] From the comparison between Examples 1 to 7 and Comparative Example 1, it can be seen that the flipping portion of the cylindrical battery explosion-proof piece of Examples 1 to 7 is provided with a thinning area, 0.15≤W1 / R1≤0.29, and the flipping portion of the cylindrical battery explosion-proof piece of Comparative Example 1 is not provided with a thinning area. After the cylindrical batteries of Examples 1 to 7 are subjected to the burst test, the flipping height δ of the explosion-proof piece is smaller. The flipping portion of the cylindrical battery of Examples 1 to 7 after flipping is relatively "flattened", which is conducive to reducing the flipping height of the flipping portion. In the design of cylindrical batteries, it is conducive to reducing the distance between the top cover and the flipping portion and improving the energy density of the cylindrical battery.

[0107] From the comparison of Example 1, Example 5 and Example 6, it can be seen that as the ratio of T2 / T1 decreases, the flip height δ of the explosion-proof plate before and after the explosion test gradually decreases. 0.5≤T2 / T1≤0.6, the flip part of the cylindrical battery is more "flattened" after flipping, which is conducive to reducing the flip height of the flip part. In the design of cylindrical batteries, it is conducive to reducing the distance between the top cover and the flip part, and improving the energy density of the cylindrical battery.

[0108] By comparing Example 1 and Example 7, it can be seen that in Example 7, the distance L1 between the second end of the thinned area and the fixed part is 0, the flip height δ of the explosion-proof plate before and after the explosion test is lower, and the flip part of the cylindrical battery is more "flattened" after flipping, which is conducive to reducing the flip height of the flip part. In the design of cylindrical batteries, it is conducive to reducing the distance between the top cover and the flip part, and improving the energy density of the cylindrical battery.

[0109] The above description is only a preferred embodiment of the present application and is not intended to limit the protection scope of the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application are included in the protection scope of the present application.

Claims

1. A cylindrical battery, characterized in that: include: case; A top cover assembly is insulated and connected to the shell, the top cover assembly comprises a top cover and an explosion-proof plate, and the top cover and the explosion-proof plate are arranged along the axial direction of the cylindrical battery; The explosion-proof disc includes a fixed portion and a flip portion, the fixed portion is connected to the top cover, the flip portion includes an electrical connection area and a thinning area, and when viewed along the axial direction, the electrical connection area, the thinning area and the fixed portion are sequentially arranged along the radial direction of the cylindrical battery; The groove is arranged in the thinned area.

2. The cylindrical battery according to claim 1, characterized in that: Along the axial direction, the projection of the turning portion is circular, and the radius of the projection of the turning portion is R1; along the radial direction, the width of the thinning area is W1; 0.15≦W1 / R1≦0.

29.

3. The cylindrical battery according to claim 2, characterized in that: 0.15≦W1 / R1≦0.

2.

4. The cylindrical battery according to claim 2, characterized in that: The radius of the cylindrical battery is R2, 1 / 3≦R1 / R2≦2 / 3.

5. The cylindrical battery according to claim 4, characterized in that: 15mm≦R2≦50mm.

6. The cylindrical battery according to claim 4, characterized in that: 7.5mm≦R1≦25mm.

7. The cylindrical battery according to any one of claims 1 to 6, characterized in that: Along the radial direction, the thinned region includes a first end close to the axis of the cylindrical battery and a second end away from the axis of the cylindrical battery; Along the radial direction, the distance between the second end and the fixing portion is L1; 0mm≦L1≦0.2mm.

8. The cylindrical battery according to claim 7, characterized in that: The distance between the groove and the first end is W2, 2 / 5≦W2 / W1≦3 / 5.

9. The cylindrical battery according to claim 7, characterized in that: The thinned area is a closed ring; the groove extends around the axis, and the groove is an open ring.

10. The cylindrical battery according to any one of claims 1 to 9, characterized in that: The electrical connection area includes a curved section and a straight section, wherein the curved section is curved away from the top cover; When viewed along the axial direction, the projection of the straight section surrounds the projection of the curved section, and the straight section connects the curved section and the thinned area; Along the axial direction, the thickness of the straight section is T1, the thickness of the thinned area is T2, and 1 / 2≦T2 / T1≦4 / 5.

11. The cylindrical battery according to claim 10, characterized in that: 1 / 2≦T2 / T1≦3 / 5.

12. The cylindrical battery according to claim 10, characterized in that: 0.2mm≦T2≦0.4mm.

13. The cylindrical battery according to any one of claims 1 to 12, characterized in that: Along the axial direction, The groove bottom thickness of the groove is T3, 0.1mm≦T3≦0.2mm.

14. The cylindrical battery according to any one of claims 1 to 13, characterized in that: The material of the explosion-proof disk includes aluminum.

15. The cylindrical battery according to any one of claims 1 to 14, characterized in that: Along the axial direction, the flip portion is thinned toward one side of the top cover to form the thinned area.

16. A battery pack, characterized in that: A cylindrical battery comprising any one of claims 1 to 15.

17. An electrical device, characterized in that: A cylindrical battery comprising any one of claims 1 to 15 or a battery pack as claimed in claim 16.

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