Cylindrical battery, battery pack and electric equipment

Abstract

The embodiment of the invention provides a cylindrical battery, a battery pack and electric equipment, the cylindrical battery comprises a shell, an electrode assembly and a collector plate, and the shell comprises a bottom wall; the electrode assembly is arranged in the shell, one end, facing the bottom wall, of the electrode assembly is provided with a tab part, and the tab part is provided with a concave part; the current collecting disc is arranged between the bottom wall and the electrode assembly and comprises a first part and a second part, the side, facing the electrode assembly, of the first part exceeds the second part and forms a convex part, and the convex part is arranged in the concave part; the second part is electrically connected with the electrode assembly, and the first part is welded to the bottom wall. In the embodiment of the scheme, the side, facing the electrode assembly, of the first part exceeds the second part and forms the convex part, and the first part is thicker and is not easy to weld through when being welded with the bottom wall, so that the bottom wall of the cylindrical battery and the collector plate have good welding reliability. The convex part is arranged at the concave part of the tab part, so that the loss of the capacity of the electrode assembly is avoided, and the energy density of the cylindrical battery is not lost while the welding reliability is improved.

Description

Technical Field

[0001] The present invention 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] Laser penetration welding is commonly used to connect the battery housing and the current collector. This technology uses a high-energy-density laser beam to instantly melt the materials being welded and form a connection.

[0003] However, in practical applications, when using this technology to weld from a thicker shell to a thinner collector plate, a higher laser power is required to ensure sufficient welding energy to penetrate the thick shell and act on the thin collector plate. However, this high power can easily cause the thin collector plate to be welded through, thereby damaging the electrode assembly. Therefore, in the existing technology, to avoid welding through the collector plate, the overall thickness of the collector plate is increased, but this takes up axial space in the electrode assembly, thereby reducing the energy density of the battery. Summary of the Invention

[0004] The purpose of the embodiments of the present invention is to provide a cylindrical battery, battery pack, and electrical equipment that achieves good reliability in welding the bottom wall and current collecting plate of the cylindrical battery without sacrificing the 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 including a bottom wall; an electrode assembly, arranged in the shell, and the electrode assembly is provided with a pole ear portion at one end facing the bottom wall, and the pole ear portion is provided with a recess; a current collecting plate, arranged between the bottom wall and the electrode assembly, the current collecting plate including a first part and a second part, the first part extending beyond the second part toward the side of the electrode assembly and forming a convex portion, and the convex portion is arranged in the recess; the second part is electrically connected to the electrode assembly, and the first part is welded to the bottom wall.

[0006] Because the first portion extends beyond the second portion toward the electrode assembly, forming a convex portion, the first portion is thicker and less likely to be welded through the bottom wall, resulting in excellent welding reliability between the bottom wall and the current collector plate of the cylindrical battery. Furthermore, the convex portion of the first portion is located within the concave portion of the electrode tab, eliminating the axial installation space of the electrode assembly and preventing loss of electrode assembly capacity. This improves welding reliability while maintaining the energy density of the cylindrical battery.

[0007] In one or more embodiments, the area of ​​the bottom wall is s0, the area of ​​the convex portion is s1; 0.005≤s1 / s0≤0.1, 227 mm 2 ≤s0≤3317mm 2The s1 / s0 ratio range and the s0 area range are conducive to forming a relatively suitable welding area between the current collecting disc and the bottom wall of the shell. When the cylindrical battery is charging and discharging, a good flow of current is formed between the current collecting disc and the bottom wall of the shell, which is conducive to reducing the temperature rise of the cylindrical battery.

[0008] In one or more embodiments, 0.025≤s1 / s0≤0.05. s1 / s0≥0.025, so that the current collecting disc and the bottom wall of the shell form a larger welding area, and a more reliable electrical connection between the current collecting disc and the bottom wall of the shell is achieved. Under harsh working conditions, the cylindrical battery can easily form a stable electrical connection between the current collecting disc and the bottom wall of the shell, and it is not easy to break. s1 / s0≤0.05, so that the current collecting disc and the electrode assembly form a larger welding area, and a more reliable electrical connection between the current collecting disc and the electrode assembly is achieved. Under harsh working conditions, the cylindrical battery can easily form a stable electrical connection between the current collecting disc and the electrode assembly, and it is not easy to break.

[0009] In one or more embodiments, the thickness of the bottom wall is d1, the thickness of the first portion is d2, and the thickness of the second portion is d3; 0.3≤d1 / (d2-d3)≤2.4, 0.25mm≤d2-d3≤1.85mm. This d1 / (d2-d3) ratio range and the d2-d3 thickness range ensure that the first portion is not easily penetrated during welding of the first portion to the bottom wall of the housing, and the first portion does not occupy space in the electrode assembly, thereby facilitating an increase in the energy of the electrode assembly and, in turn, the energy density of the cylindrical battery.

[0010] In one or more embodiments, 0.6≤d1 / (d2-d3)≤1.7. When d1 / (d2-d3)≤1.7, the convex portion is thicker, making it more difficult for the first portion to be welded through during the welding process between the first portion and the bottom wall of the shell. When d1 / (d2-d3)≥0.6, the convex portion is not too thick, leaving more thickness space for the concave portion, so that the bottom of the concave portion of the pole ear is farther away from the active material coating area, making it less likely that the active material adjacent to the concave portion will fall off due to the bottom of the concave portion being affected by the convex portion, thereby improving the reliability of the cylindrical battery.

[0011] In one or more embodiments, 0.1 mm ≤ d3 ≤ 0.2 mm. When d3 is within this thickness range, a more reliable electrical connection is formed between the second portion and the electrode assembly during welding. Furthermore, the thinner second portion provides more installation space for the electrode assembly, which helps increase the energy of the electrode assembly and, in turn, the energy density of the cylindrical battery.

[0012] In one or more embodiments, the electrode assembly includes a pole piece in a wound state; an empty foil area is provided at one end of the pole piece along the axial direction of the cylindrical battery, and the empty foil area is flattened to form a pole ear portion, and the pole ear portion includes a first pole ear portion and a second pole ear portion, and the second pole ear portion is welded to the second portion; along the axial direction, the thickness of the first pole ear portion is less than the thickness of the second pole ear portion, so as to form a recess in the pole ear portion.

[0013] In one or more embodiments, the tabs of the electrode assembly are formed by flattening, forming full tabs. This increases the current carrying capacity of the tabs and reduces heat generation during operation of the cylindrical battery. Furthermore, the thickness of the first tab is designed to be smaller than that of the second tab. A recess is formed in the tab to accommodate the convex portion of the current collector. This recess does not occupy the axial installation space of the electrode assembly, thus preventing a loss in energy density.

[0014] In one or more embodiments, the electrode is provided with a coating area connected to the empty foil area; when the electrode is unfolded, the empty foil area includes a first section and a second section. Along the width direction of the electrode, the second section extends beyond the first section on the side away from the coating area. The first section forms a first pole ear portion after winding, and the second section forms a second pole ear portion after winding and flattening. In the manufacturing process of cylindrical batteries, the empty foil area of ​​the electrode is cut so that the second section extends beyond the first section on the side away from the coating area. Thereafter, the first section forms a first pole ear portion after winding, and the second section forms a second pole ear portion after winding and flattening. Axially, the thickness of the first pole ear portion is less than that of the second pole ear portion, and a recess is formed on the pole ear portion to accommodate the protrusion of the current collecting plate. The protrusion does not occupy the axial installation space of the electrode assembly and does not cause a loss of energy density of the cylindrical battery.

[0015] In one or more embodiments, the first part and the bottom wall are laser welded; and / or the second part and the second pole ear are laser welded. The first part and the bottom wall, the second part and the second pole ear are laser welded, and the manufacturing of the cylindrical battery is more convenient.

[0016] In one or more embodiments, there is a gap between the convex portion and the concave portion along the axial direction of the cylindrical battery, and the height of the gap is h. On the one hand, during the assembly of the cylindrical battery, there is a gap between the convex portion and the concave portion (for example, achieved by the height of the convex portion being lower than the depth of the concave portion). Then, after the convex portion of the current collecting plate is completely disposed in the concave portion, it is beneficial for the second portion of the current collecting plate to form good contact with the electrode assembly. On the other hand, in the step of laser welding the bottom wall of the shell and the first portion of the current collecting plate, the air layer formed by the gap can reduce the heat directly conducted from the convex portion of the current collecting plate to the bottom of the concave portion of the electrode assembly, thereby reducing the probability of damage to the electrode assembly during the laser welding process between the bottom wall of the shell and the first portion of the current collecting plate.

[0017] In one or more embodiments, the height of the gap is h, and 0.1 mm ≤ h ≤ 0.3 mm. Within this height range, the distance between the protrusion and the recess is within a suitable range, the second portion of the current collecting plate and the electrode assembly are in good contact, and the probability of damage to the electrode assembly during laser welding between the bottom wall of the housing and the first portion of the current collecting plate is low.

[0018] In one or more embodiments, the second portion surrounds the first portion when viewed axially along the cylindrical battery. This facilitates positioning the protrusion near the center of the cylindrical battery, facilitating positioning and rapid welding of the bottom wall and the first portion. Furthermore, the coordination of the protrusion and recess enhances the mechanical connection stability between the current collector and the electrode assembly, improving the overall structural strength of the cylindrical battery.

[0019] In one or more embodiments, when viewed along the axial direction of the cylindrical battery, the first portion surrounds the second portion. The weld line between the first portion and the bottom wall can be distributed along a circular path, which helps to reduce the problem of excessive concentration of welding energy affecting the weld line quality.

[0020] A second aspect of the present application provides a battery pack comprising a cylindrical battery according to any of the above embodiments.

[0021] A third aspect of the present application provides an electrical device comprising a cylindrical battery or battery pack according to any one of the above embodiments.

[0022] Beneficial effects of the embodiments of the present invention:

[0023] The cylindrical battery, battery pack, and electrical device provided in an embodiment of the present invention include a housing, an electrode assembly, and a current collector. The housing includes a bottom wall. The electrode assembly is disposed within the housing, and an end of the electrode assembly facing the bottom wall is provided with a tab, which is provided with a recess. The current collector is disposed between the bottom wall and the electrode assembly. The current collector includes a first portion and a second portion. The first portion extends beyond the second portion toward the electrode assembly to form a convex portion, which is disposed within the recess. The second portion is electrically connected to the electrode assembly, and the first portion is welded to the bottom wall. In this embodiment, because the first portion extends beyond the second portion toward the electrode assembly to form a convex portion, the first portion is relatively thick and is less likely to be welded through when welded to the bottom wall. This ensures good welding reliability between the bottom wall of the cylindrical battery and the current collector. At the same time, the convex portion of the first part is arranged in the concave portion of the pole ear portion, and will not occupy the axial installation space of the electrode assembly. That is, the concave portion of the pole ear portion in the electrode assembly provides an installation space for the first part. Therefore, the first part does not occupy the coating space for the active material in the electrode assembly, and will not cause the loss of the capacity of the electrode assembly, thereby improving the welding reliability without losing the energy density of the cylindrical battery.

[0024] Of course, it is not necessary to achieve all of the above advantages simultaneously when implementing any product or method of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other embodiments can also be obtained based on these drawings.

[0026] Figure 1 A schematic structural diagram of a cylindrical battery provided in an embodiment of the present application;

[0027] Figure 2 for Figure 1 Schematic diagram of the cross-sectional structure of the cylindrical battery shown;

[0028] Figure 3 for Figure 2 Schematic diagram of the structure of area A;

[0029] Figure 4 for Figure 1 A schematic diagram of the welding plane of the bottom wall and the current collecting plate of the cylindrical battery shown;

[0030] Figure 5 for Figure 3 Structural exploded view of the structure shown;

[0031] Figure 6 for Figure 1 A schematic diagram of the structure of the pole piece of the cylindrical battery in the unfolded state;

[0032] Figure 7 A schematic structural diagram of another cylindrical battery electrode in an unfolded state provided in an embodiment of the present application;

[0033] Figure 8 An exploded view of a portion of the structure of another cylindrical battery provided in an embodiment of the present application;

[0034] Figure 9 A schematic diagram of the structure of the battery pack provided in an embodiment of the present application;

[0035] Figure 10 A schematic diagram of the structure of the first electrical equipment provided in an embodiment of the present application;

[0036] Figure 11 A schematic structural diagram of the second type of electrical equipment provided in an embodiment of the present application.

[0037] The reference numerals are as follows:

[0038] Shell 10, bottom wall 11, side wall 12, electrode assembly 20, pole ear portion 21, recess 211, first pole ear portion 212, second pole ear portion 213, pole piece 201, empty foil area 2011, first section 20111, second section 20112, coating area 2012, current collecting plate 30, first part 31, second part 32, protrusion 311, top cover 40, center hole 50,

[0039] Cylindrical battery 100, battery pack 200, power-consuming device 300,

[0040] Gap J0, axial direction Y, radial direction X, axis L0, width direction W, winding direction R. DETAILED DESCRIPTION

[0041] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field based on this application are within the scope of protection of the present invention.

[0042] In this application, unless otherwise expressly specified or limited, the terms "installed," "connected," "connected," "fixed," and the like should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to mechanical connections or electrical connections; they may refer to direct connections or indirect connections through an intermediate medium; and they may refer to internal connections between two components. A person of ordinary skill in the art will understand the specific meanings of the above terms in this application based on the specific circumstances. The term "and / or" as used herein includes any and all combinations of one or more of the relevant listed items.

[0043] In the description of the embodiments of this application, the technical terms "first," "second," etc. are used only to distinguish different objects and should not be understood to indicate or imply relative importance or to implicitly indicate the quantity, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, the meaning of "plurality" is more than two, unless otherwise specifically defined.

[0044] References to "embodiments" herein mean that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the present application. The appearance of such phrases in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. The various embodiments of the present application may be combined with each other unless there is a conflict.

[0045] In the existing cylindrical battery manufacturing process, when laser penetration welding technology is used to connect the bottom wall of the shell and the current collector, the bottom wall of the shell, as a thick part, requires higher laser power to achieve full penetration. However, when this energy is transferred to the thin current collector, it can easily lead to local overheating or even welding through, causing damage to the diaphragm of the cylindrical battery. To avoid welding through the current collector, the overall thickness of the current collector is increased, but doing so will squeeze the axial space of the electrode assembly, which will have a significant impact on the energy density of the cylindrical battery.

[0046] Faced with the above-mentioned problems, this application redesigned the welding interface structure of the electrode assembly and the current collector plate, providing a recess in the electrode assembly's lugs and a convex portion in the corresponding area of ​​the current collector plate. When laser welding the bottom wall of the housing and the current collector plate, the laser can be focused on the convex portion for welding, thickening the welding area by the convex portion, thereby achieving a good and reliable welding of the bottom wall of the cylindrical battery and the current collector plate. At the same time, the peripheral edge of the current collector plate convex portion maintains a thin-wall design, providing more installation space for the electrode assembly and reducing the impact on the energy density of the cylindrical battery.

[0047] Figure 1 A schematic diagram of the structure of a cylindrical battery provided in an embodiment of the present application is shown in FIG. Figure 1 As shown, an embodiment of the present application provides a cylindrical battery 100, wherein the axis of the cylindrical battery 100 is L0. The radial direction of the cylindrical battery 100 is X, which is in a plane perpendicular to the axis L0 and 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. The length of the cylindrical battery 100 is L, and the diameter of the cylindrical battery 100 is D.

[0048] In one or more embodiments, 17 mm ≤ D ≤ 65 mm, but is not limited thereto. For example, D may be 17 mm, 18 mm, 20 mm, 21 mm, 25 mm, 30 mm, 35 mm, 40 mm, 45 mm, 49 mm, 50 mm, 55 mm, 60 mm, 65 mm, or any value between any two values.

[0049] In one or more embodiments, 40 mm ≤ L ≤ 250 mm, but the present invention is not limited thereto. For example, L may be 40 mm, 48 mm, 50 mm, 60 mm, 65 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, 205 mm, 210 mm, 220 mm, 230 mm, 240 mm, 250 mm, or any value between any two values.

[0050] Figure 2 for Figure 1 The cross-sectional structural diagram of the cylindrical battery 100 is shown. Figure 3 for Figure 2 The structural diagram of area A is as follows: Figure 2 and Figure 3 As shown, a cylindrical battery 100 includes a housing 10, an electrode assembly 20, and a current collecting tray 30. The housing 10 includes a bottom wall 11; the electrode assembly 20 is disposed within the housing 10, and an end of the electrode assembly 20 facing the bottom wall 11 is provided with a tab 21, and the tab 21 is provided with a recess 211; the current collecting tray 30 is disposed between the bottom wall 11 and the electrode assembly 20, and includes a first portion 31 and a second portion 32. The first portion 31 extends beyond the second portion 32 toward the side of the electrode assembly 20 to form a protrusion 311, which is disposed in the recess 211; the second portion 32 is electrically connected to the electrode assembly 20, and the first portion 31 is welded to the bottom wall 11, such as by laser welding.

[0051] In the embodiment of this solution, because the first portion 31 extends beyond the second portion 32 on the side facing the electrode assembly 20 and forms a protrusion 311, the first portion 31 is relatively thick and is less likely to be penetrated during welding to the bottom wall 11, thereby improving the weld reliability between the bottom wall 11 and the current collecting plate 30 of the cylindrical battery 100. Furthermore, the protrusion 311 of the first portion 31 is disposed within the recess 211 of the tab 21 and does not occupy the axial installation space of the electrode assembly 20. That is, in the electrode assembly 20, the recess 211 of the tab 21 provides installation space for the first portion 31. Consequently, the first portion 31 does not occupy the coating space within the electrode assembly 20 for the active material, resulting in no loss of capacity in the electrode assembly 20. This improves welding reliability while maintaining the energy density of the cylindrical battery 100.

[0052] In one or more embodiments, the housing 10 includes a sidewall 12, the bottom of the sidewall 12 being connected to the bottom wall 11 to form an integral metal structure. The housing 10 serves as the first electrode of the cylindrical battery 100. The cylindrical battery 100 includes a top cover 40, which is disposed on the top of the sidewall 12 away from the bottom wall 11. The top cover 40 encapsulates the electrode assembly 20 within the housing 10, and the top cover 40 and the electrode assembly 20 are electrically connected, serving as the second electrode of the cylindrical battery 100.

[0053] In one or more embodiments, the axis L0 of the cylindrical battery 100 passes through the central hole 50 of the cylindrical battery 100 .

[0054] In one or more embodiments, a gap J0 is defined between the protrusion 311 and the recess 211 along the axial direction Y of the cylindrical battery 100. During assembly of the cylindrical battery 100, the gap J0 is defined between the protrusion 311 and the recess 211 (e.g., achieved by the height of the protrusion 311 being less than the depth of the recess 211). This facilitates good contact between the second portion 32 of the current collecting tray 30 and the electrode assembly 20 after the protrusion 311 of the current collecting tray 30 is fully seated in the recess 211. Furthermore, during laser welding of the bottom wall 11 of the housing 10 and the first portion 31 of the current collecting tray 30, the air layer formed by the gap J0 reduces the amount of heat directly transferred from the protrusion 311 of the current collecting tray 30 to the recess 211 of the electrode assembly 20, thereby reducing the likelihood of damage to the electrode assembly 20 during the laser welding process.

[0055] In one or more embodiments, along the axial direction Y of the cylindrical battery 100 , the height of the gap J0 is h, and 0.1 mm ≤ h ≤ 0.3 mm.

[0056] In one or more embodiments, for example, h may be 0.1 mm, 0.11 mm, 0.12 mm, 0.13 mm, 0.14 mm, 0.15 mm, 0.16 mm, 0.17 mm, 0.18 mm, 0.19 mm, 0.20 mm, 0.21 mm, 0.22 mm, 0.23 mm, 0.24 mm, 0.25 mm, 0.26 mm, 0.27 mm, 0.28 mm, 0.29 mm, or 0.3 mm, or any value between any two values. Within this height range of h, the gap J0 between the protrusion 311 and the recess 211 is within a suitable range, the second portion 32 of the current collecting plate 30 and the electrode assembly 20 are in good contact, and during the laser welding process of the bottom wall 11 of the housing 10 and the first portion 31 of the current collecting plate 30, the welding reliability between the bottom wall 11 and the first portion 31 of the current collecting plate 30 is good, and the probability of damaging the electrode assembly 20 is low.

[0057] Figure 4 for Figure 1 The bottom wall 11 of the cylindrical battery 100 and the current collecting plate 30 are shown in FIG. Figure 4 As shown, in one or more embodiments, the area of ​​the bottom wall 11 is s0, the area of ​​the protrusion 311 is s1; 0.005≤s1 / s0≤0.1, 227mm 2 ≤s0≤3317mm 2 .

[0058] In one or more embodiments, for example, s1 / s0 may be: 0.005, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, or a value between any two values ​​therebetween.

[0059] In one or more embodiments, for example, s0 may be: 227 mm 2 , 254mm 2 , 320mm 2 、346mm 2 , 420mm 2 , 520mm 2 , 620mm 2 , 720mm 2 , 820mm 2 , 920mm 2 , 962mm 2 , 1020mm 2 , 1120mm 2 、1220mm 2 、1320mm 2 、1420mm 2 , 1520mm 2 、1620mm 2 、1720mm 2 、1820mm 2 、1920mm 2 、1994mm 2 , 2020mm 2 , 2120mm 2 , 2220mm 2 , 2320mm 2 , 2420mm 2 , 2520mm 2 、2620mm 2 、2720mm 2 , 2820mm 2 、2920mm 2 、3020mm 2 、3120mm 2 、3220mm 2 、3310mm 2 、3317mm 2 , or a value between any two values ​​in between.

[0060] The ratio range of s1 / s0 and the area range of s0 are conducive to forming a welding area of ​​a relatively suitable size between the current collecting plate 30 and the bottom wall 11. When the cylindrical battery 100 is charging and discharging, a good flow of current is formed between the current collecting plate 30 and the bottom wall 11, which is conducive to reducing the temperature rise of the cylindrical battery 100.

[0061] In one or more embodiments, 0.025≤s1 / s0≤0.05. s1 / s0≥0.025, so that the current collecting disc 30 and the bottom wall 11 form a larger welding area, thereby achieving a more reliable electrical connection between the current collecting disc 30 and the bottom wall 11. Under harsh working conditions, the cylindrical battery 100 can easily form a stable electrical connection between the current collecting disc 30 and the bottom wall 11, and it is not easy to break. s1 / s0≤0.05, so that the current collecting disc 30 and the electrode assembly 20 form a larger welding area, thereby achieving a more reliable electrical connection between the current collecting disc 30 and the electrode assembly 20. Under harsh working conditions, the cylindrical battery 100 can easily form a stable electrical connection between the current collecting disc 30 and the electrode assembly 20, and it is not easy to break.

[0062] Figure 5 for Figure 3 The structural explosion diagram of the structure shown is as follows: Figure 5 As shown, in one or more embodiments, the thickness of the bottom wall 11 is d1, the thickness of the first portion 31 is d2, and the thickness of the second portion 32 is d3; 0.3≤d1 / (d2-d3)≤2.4, 0.25mm≤d2-d3≤1.85mm.

[0063] In one or more embodiments, for example, d1 / (d2-d3) can be: 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, or a value between any two values.

[0064] In one or more embodiments, for example, d1 may be: 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, or a value between any two values ​​therebetween.

[0065] In one or more embodiments, for example, d2-d3 can be: 0.25mm, 0.35mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1.0mm, 1.05mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, 1.6mm, 1.7mm, 1.8mm, 1.85mm, or a value between any two values.

[0066] Within the ratio range of d1 / (d2-d3) and the thickness range of d2-d3, during the welding process between the first part 31 and the bottom wall 11, the first part 31 is not easily welded through, and the first part 31 does not occupy the space of the electrode assembly 20, which is beneficial to improving the energy of the electrode assembly 20 and further improving the energy density of the cylindrical battery 100.

[0067] In one or more embodiments, 0.6≤d1 / (d2-d3)≤1.7. When d1 / (d2-d3)≤1.7, the protrusion 311 is thicker, making it more difficult for the first portion 31 to be welded through during the welding process between the first portion 31 and the bottom wall 11. When d1 / (d2-d3)≥0.6, the protrusion 311 is thinner, leaving more thickness space for the recess 211, so that the bottom of the recess 211 of the tab portion 21 is farther away from the active material coating area, making it less likely that the active material adjacent to the recess 211 will fall off due to the bottom of the recess 211 being affected by the protrusion 311, thereby improving the reliability of the cylindrical battery 100.

[0068] In one or more embodiments, 0.1 mm ≤ d3 ≤ 0.2 mm. When d3 is within this thickness range, the second portion 32 and the electrode assembly 20 are welded together to form a more reliable electrical connection. Furthermore, the thinner second portion 32 provides more installation space for the electrode assembly 20, which helps increase the energy consumption of the electrode assembly 20 and, in turn, the energy density of the cylindrical battery 100.

[0069] In one or more embodiments, for example, d3 may be: 0.10 mm, 0.11 mm, 0.12 mm, 0.13 mm, 0.14 mm, 0.15 mm, 0.16 mm, 0.17 mm, 0.18 mm, 0.19 mm, 0.20 mm, or a value between any two values ​​therebetween.

[0070] In one or more embodiments, the electrode assembly 20 includes a wound electrode sheet 201. A hollow foil region 2011 is provided at one end of the electrode sheet 201 along the axial direction Y of the cylindrical battery 100. The hollow foil region 2011 refers to an area on the electrode sheet 201 that is not coated with active material. The hollow foil region 2011 is flattened to form a lug portion 21. The lug portion 21 includes a first lug portion 212 and a second lug portion 213. The second lug portion 213 is welded to the second portion 32. Along the axial direction Y, the thickness of the first lug portion 212 is less than that of the second lug portion 213, thereby forming a recess 211 in the lug portion 21.

[0071] In one or more embodiments, the tab portion 21 of the electrode assembly 20 is formed by flattening, forming a full tab. This helps increase the current carrying capacity of the tab portion 21 and reduces the heat generated by the cylindrical battery 100 during operation. Furthermore, the thickness of the first tab portion 212 is designed to be smaller than the thickness of the second tab portion 213. A recess 211 is formed in the tab portion 21 to accommodate the protrusion 311 of the current collecting plate 30. The protrusion 311 does not occupy the axial installation space of the electrode assembly 20, thereby preventing a loss in energy density.

[0072] In one or more embodiments, the first portion 31 and the bottom wall 11 are laser welded. The first portion 31 and the bottom wall 11 are laser welded, and the manufacturing of the cylindrical battery 100 is more convenient.

[0073] In one or more embodiments, the second portion 32 and the second pole ear portion 213 are laser welded. The second portion 32 and the second pole ear portion 213 adopt a laser welding process, which makes the manufacture of the cylindrical battery 100 more convenient.

[0074] In one or more embodiments, the electrode sheet 201 is a positive electrode sheet, and the electrode assembly 20 further includes a negative electrode sheet. The positive electrode sheet, separator, and negative electrode sheet are sequentially stacked and wound. The positive electrode sheet is electrically connected to the bottom wall 11, which serves as the positive electrode of the cylindrical battery 100. The negative electrode sheet is electrically connected to the top cover 40, which serves as the negative electrode of the cylindrical battery 100.

[0075] In one or more embodiments, the electrode sheet 201 is a negative electrode sheet, and the electrode assembly 20 further includes a positive electrode sheet. The positive electrode sheet, the separator, and the negative electrode sheet are sequentially stacked and wound. The negative electrode sheet is electrically connected to the bottom wall 11, which serves as the negative electrode of the cylindrical battery 100. The positive electrode sheet is electrically connected to the top cover 40, which serves as the positive electrode of the cylindrical battery 100.

[0076] Figure 6 for Figure 1 The schematic structural diagram of the pole piece 201 of the cylindrical battery 100 in the unfolded state is shown in FIG. Figure 6 As shown, in one or more embodiments, the electrode 201 is provided with a coating area 2012 connected to the hollow foil area 2011; the coating area 2012 refers to the area on the electrode 201 where the active material is coated. When the electrode 201 is unfolded, the hollow foil area 2011 includes a first section 20111 and a second section 20112. Along the width direction W of the electrode 201, the second section 20112 extends beyond the first section 20111 on a side away from the coating area 2012. The first section 20111 forms a first electrode ear portion 212 after being wound, and the second section 20112 forms a second electrode ear portion 213 after being wound and flattened.

[0077] During the assembly of the cylindrical battery 100, the hollow foil area 2011 is wound and flattened to form the tab portion 21. The first section 20111 and the second section 20112 of the tab portion 21 have different widths, thereby forming a recess 211.

[0078] In one or more embodiments, during the manufacturing process of the cylindrical battery 100, the hollow foil area 2011 of the electrode sheet 201 of equal width is cut so that the second section 20112 extends beyond the first section 20111 on the side away from the coating area 2012. Subsequently, the first section 20111 is wound to form a first electrode lug 212, and the second section 20112 is wound and flattened to form a second electrode lug 213. Along the axial direction Y, the thickness of the first electrode lug 212 is less than that of the second electrode lug 213. A recess 211 is formed on the electrode lug 21 to accommodate the protrusion 311 of the current collecting plate 30. The protrusion 311 does not occupy the axial installation space of the electrode assembly 20, thereby preventing a loss in the energy density of the cylindrical battery 100.

[0079] In one or more embodiments, Figure 6 As shown, the winding direction of the pole piece 201 is R, and the winding direction R is from the first section 20111 to the second section 20112. The winding process of the pole piece 201 is starting from the first section 20111 and winding the pole piece 201 in the winding direction R toward the second section 20112.

[0080] like Figure 3 As shown, after the wound electrode sheet 201 is flattened, in one or more embodiments, the second portion 32 surrounds the first portion 31 when viewed along the axial direction Y of the cylindrical battery 100. This facilitates the positioning of the protrusion 311 near the center of the cylindrical battery 100, where the welding area is more concentrated, facilitating the positioning and rapid welding of the bottom wall 11 and the first portion 31. Furthermore, the coordination between the protrusion 311 and the recess 211 enhances the mechanical connection stability between the current collecting plate 30 and the electrode assembly 20, thereby improving the overall structural strength of the cylindrical battery 100.

[0081] This is different from the structure of the cylindrical battery 100 in the above embodiment, where the second portion 32 surrounds the first portion 31 when viewed along the axial direction Y of the cylindrical battery 100. Figure 7 A schematic structural diagram of another cylindrical battery 100 in an embodiment of the present application, wherein the electrode 201 is in an unfolded state. Figure 7 As shown, the winding direction of the pole piece 201 is R, and the winding direction R is from the second section 20112 to the first section 20111. The winding process of the pole piece 201 is starting from the second section 20112 and winding the pole piece 201 in the winding direction R toward the first section 20111.

[0082] Figure 8This is an exploded view of a portion of the structure of another cylindrical battery 100 provided in an embodiment of the present application. Figure 8 As shown, after the wound electrode sheet 201 is flattened, in one or more embodiments, when viewed along the axial direction Y of the cylindrical battery 100, the first portion 31 surrounds the second portion 32. The weld line between the bottom wall 11 and the first portion 31 can be distributed along a circular path, which helps reduce the impact of excessive welding energy concentration on weld line quality.

[0083] This application provides a battery pack 200, Figure 9 A schematic diagram of the structure of the battery pack provided in the embodiment of the present application is shown in FIG. Figure 9 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 a combination of the two.

[0084] The present application provides an electric device 300 , comprising the cylindrical battery 100 or the battery pack 200 according to any one of the above embodiments.

[0085] In one or more embodiments, Figure 10 A schematic diagram of the structure of the first type of electrical equipment provided in the embodiment of the present application is shown in FIG. Figure 10 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.

[0086] In one or more embodiments, Figure 11 A schematic diagram of the structure of the second type of electrical equipment provided in the embodiment of the present application is shown in FIG. Figure 11 As shown, the electric device 300 includes the cylindrical battery 100 in the above embodiment.

[0087] This application does not specifically limit the electrical equipment, and the electrical equipment includes electrical equipment known in the prior art. For example, the electrical equipment includes but is not limited to backup power supplies, two-wheeled vehicles, drones, power tools, or energy storage devices.

[0088] Example

[0089] Hereinafter, the embodiments of the present application will be described in more detail with reference to Examples and Comparative Examples. Various tests and evaluations were performed according to the following methods.

[0090] Test equipment:

[0091] Octahedral drum: The diameter of the inscribed circle of the drum is 230mm, the length is 230mm, and the wall thickness is 10mm.

[0092] Roller test method:

[0093] The cylindrical battery 100 was subjected to an octahedral drum test at a test speed of 66 rpm for 100 minutes, and the resistance of the cylindrical battery 100 before and after the test, as well as the terminal voltage of the cylindrical battery 100 before and after the test, were compared.

[0094] The drum test is considered passed if the terminal voltage of the cylindrical battery 100 changes within 100 mV before and after the test, and the resistance of the cylindrical battery 100 changes within 20%. A failure is considered failed if the terminal voltage of the cylindrical battery 100 changes by more than 100 mV before and after the test, or the resistance of the cylindrical battery 100 changes by more than 20%.

[0095] The terminal voltage of the cylindrical battery 100 can be tested by a battery tester (battery tester model: Neware CT-4016-5V-100A), and the resistance of the cylindrical battery 100 can be tested by an internal resistance tester (internal resistance tester model: HIOKIBT3563).

[0096] In order to verify the seismic resistance of the cylindrical battery 100 in the present application, roller tests were conducted on 9 groups of embodiments (Examples 1 to 9) and 4 groups of comparative examples (Comparative Examples 1 to 4). For each group of cylindrical batteries 100 in the embodiments and comparative examples, when observed along the axial direction Y of the cylindrical battery 100, the second portion 32 surrounds the first portion 31. The number of cylindrical batteries 100 in each group of embodiments and comparative examples is 10, and the specific dimensions of each group of cylindrical batteries 100 are shown in Table 1.

[0097] The cylindrical batteries 100 of each group of the aforementioned embodiments and each group of comparative examples were subjected to the above-mentioned drum test. After the embodiments and comparative examples were tested, the number Q1 of cylindrical batteries 100 that passed the test in each group of tests was counted, as shown in Table 1.

[0098] Welding yield test method:

[0099] 1.CCD camera (charge coupled device camera, Basler aca 1920-155um) online monitoring;

[0100] The CCD camera captures images of the weld wires after welding. Based on the CCD camera's previous deep learning algorithm for normal and defective weld wires, it distinguishes the differences between defective areas, such as burst points, and normal areas by extracting grayscale, contrast, and edge features, thereby identifying defective welds.

[0101] 2. LWM (laser welding monitoring system, YW50 Welding Monitor (optical monitoring) + AE-100M (acoustic)) online monitoring:

[0102] Various sensors are used to monitor the physical signals of the welding process in real time, including optical, thermal, or acoustic signals. Optical signal monitoring: detecting changes in the light intensity and spectrum of laser reflection, molten pool radiation, or plasma emission; thermal signal monitoring: measuring temperature distribution through infrared sensors; acoustic signal monitoring: using piezoelectric sensors to capture the sound waves generated by welding (for example, explosion points are accompanied by abnormal acoustic emissions); welding defects can change the pattern of these signals (such as peak value, frequency, or stability), and anomalies can be identified through signal processing algorithms (such as FFT or machine learning).

[0103] In order to verify the welding yield of the cylindrical battery 100 in this application, the cylindrical batteries 100 of 9 groups of embodiments (Examples 1 to 9) and 4 groups of comparative examples (Comparative Examples 1 to 4) were subjected to the above-mentioned CCD camera online monitoring and LWM online monitoring.

[0104] The number of cylindrical batteries 100 in each set of Examples and Comparative Examples was 1000. If the second portion 32 of the current collecting tray and the electrode assembly 20 were properly welded, and the first portion 31 and the bottom wall 11 were properly welded, the cylindrical battery 100 passed the welding test. If any abnormality occurred in the welding between the second portion 32 of the current collecting tray and the electrode assembly 20, or the welding between the first portion 31 and the bottom wall 11, the cylindrical battery 100 failed the welding test. After the Examples and Comparative Examples were tested, the percentage of cylindrical batteries 100 that passed the test in each set of tests was calculated as the welding yield, as shown in Table 1.

[0105]

[0106]

[0107] Remark:

[0108] s1: the area of ​​the convex part;

[0109] s0: area of ​​the bottom wall;

[0110] d1: thickness of the bottom wall;

[0111] d2: thickness of the first part;

[0112] d3: thickness of the second part;

[0113] d2-d3: thickness of the convex part.

[0114] As shown in Table 1, in Comparative Example 1, s1 / s0 = 0.0025, the ratio of the area of ​​the current collecting plate protrusion to the area of ​​the bottom wall is small, and the small protrusion area is not conducive to forming a good weld between the protrusion and the bottom wall. In Comparative Example 1, only 8 cylindrical batteries passed the roller test, and 2 cylindrical batteries failed the roller test. In Comparative Example 2, s1 / s0 = 0.1505, the ratio of the area of ​​the current collecting plate protrusion to the area of ​​the bottom wall is large, which easily leads to a small area of ​​the second part, which is not conducive to forming a good weld between the second part and the electrode assembly. In Comparative Example 2, only 8 cylindrical batteries passed the roller test, and 2 cylindrical batteries failed the roller test. In the nine groups of Examples 1 to 9, 0.005≤s1 / s0≤0.1, and all 10 cylindrical batteries in each group of Examples passed the roller test. It can be concluded that under the parameters of 0.005≤s1 / s0≤0.1, cylindrical batteries have good seismic resistance.

[0115] It can be seen from Table 1 that in Examples 1 to 5, the bottom wall area of ​​the cylindrical battery is 1994 mm 2 The bottom wall thickness of the cylindrical battery is 0.6 mm, and the ratio of the bottom wall thickness to the convex thickness d1 / (d2-d3) is 1.7. In Example 1, the convex area is 10 mm 2 The convex area is small, which affects the welding of the convex part and the bottom wall of the current collecting plate. The welding yield of the cylindrical battery is 99.50%. In Examples 4 and 5, the convex area is 150mm 2 , 200mm 2 The convex area is large, resulting in a smaller area of ​​the second part of the current collecting plate, which affects the welding of the second part of the current collecting plate and the electrode assembly. The welding yield of the cylindrical battery is 99.60%. In Examples 2 to 3, the convex area is 50mm 2 , 100mm 2 , 0.025≤s1 / s0≤0.05. Within this s1 / s0 range, the areas of the convex portion and the second portion of the current collecting disc are moderate. At the same time, it is easy to weld the convex portion and the bottom wall of the current collecting disc, and the second portion of the current collecting disc and the electrode assembly. The welding yield of the cylindrical battery is higher, both at 99.70%.

[0116] As can be seen from Table 1: In Comparative Example 4, the bottom wall thickness of the cylindrical battery is 0.6mm, and the ratio of the bottom wall thickness to the convex thickness is d1 / (d2-d3)=4. The convex thickness is relatively thin, and the convex is easily welded through when the laser energy is large. The welding yield of the cylindrical battery is 99.00%, which is a low welding yield. In the 9 groups of embodiments from Example 1 to Example 9, the bottom wall thickness of the cylindrical battery is 0.6mm, and the ratio of the bottom wall thickness to the convex thickness is 0.3≤d1 / (d2-d3)≤2.4. The convex thickness is relatively thick, and the welding yield of the cylindrical battery is not less than 99.40%, which is a high welding yield. It can be concluded that under the parameters of 0.3≤d1 / (d2-d3)≤2.4, the welding yield of the cylindrical battery is high.

[0117] As shown in Table 1, in Example 6, the bottom wall thickness of the cylindrical battery is 0.6 mm, the ratio of the bottom wall thickness to the convex thickness is d1 / (d2-d3) = 2.4, the convex thickness is relatively thin, and the welding yield of the cylindrical battery is 99.40%. In the eight groups of examples from Examples 1 to 5 and Examples 7 to 9, the bottom wall thickness of the cylindrical battery is 0.6 mm, the ratio of the bottom wall thickness to the convex thickness is 0.3≤d1 / (d2-d3)≤1.7, the convex thickness is relatively thick, and the welding yield of the cylindrical battery is not less than 99.50%, which is a high welding yield. It can be concluded that under the parameters of 0.3≤d1 / (d2-d3)≤1.7, the welding yield of the cylindrical battery is high. In Comparative Example 3, the bottom wall thickness of the cylindrical battery is 0.6 mm, and the ratio of the bottom wall thickness to the convex thickness is d1 / (d2-d3)=0.2. The convex thickness is too thick, which easily compresses the coating space for the active material in the electrode assembly 20, affecting the capacity of the electrode assembly.

[0118] The above description is only a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention are included in the scope of protection of the present invention.

Claims

1. A cylindrical battery, characterized in that: include: a housing including a bottom wall; An electrode assembly is disposed in the housing, wherein one end of the electrode assembly facing the bottom wall is provided with an electrode ear portion, and the electrode ear portion is provided with a recess; a current collecting plate disposed between the bottom wall and the electrode assembly, the current collecting plate comprising a first portion and a second portion, the first portion extending beyond the second portion toward the electrode assembly to form a convex portion, the convex portion being disposed in the concave portion; The second portion is electrically connected to the electrode assembly, and the first portion is welded to the bottom wall.

2. The cylindrical battery according to claim 1, characterized in that: The area of ​​the bottom wall is s0, and the area of ​​the convex portion is s1; 0.005≤s1 / s0≤0.1, 227mm 2 ≤s0≤3317mm 2 .

3. The cylindrical battery according to claim 2, characterized in that: 0.025≤s1 / s0≤0.

05.

4. The cylindrical battery according to any one of claims 1 to 3, characterized in that: The thickness of the bottom wall is d1, the thickness of the first portion is d2, and the thickness of the second portion is d3; 0.3≤d1 / (d2-d3)≤2.4, 0.25mm≤d2-d3≤1.85mm.

5. The cylindrical battery according to claim 4, characterized in that: 0.6≤d1 / (d2-d3)≤1.

7.

6. The cylindrical battery according to any one of claims 1 to 5, characterized in that: 0.1mm≤d3≤0.2mm.

7. The cylindrical battery according to any one of claims 1 to 6, characterized in that: The electrode assembly includes a pole piece in a wound state; An empty foil area is provided at one end of the pole piece along the axial direction of the cylindrical battery, and the empty foil area is flattened to form the pole ear portion, and the pole ear portion includes a first pole ear portion and a second pole ear portion, and the second pole ear portion and the second portion are welded; Along the axial direction, the thickness of the first pole lug portion is smaller than the thickness of the second pole lug portion, so that the recessed portion is formed in the pole lug portion.

8. The cylindrical battery according to claim 7, characterized in that: The electrode is provided with a coating area connected to the empty foil area; When the pole piece is unfolded, the empty foil area includes a first section and a second section. Along the width direction of the pole piece, the second section exceeds the first section on the side away from the coating area. The first section forms the first pole ear portion after being wound, and the second section forms the second pole ear portion after being wound and flattened.

9. The cylindrical battery according to claim 7, characterized in that: The first portion and the bottom wall are laser welded; and / or the second portion and the second pole lug are laser welded.

10. The cylindrical battery according to any one of claims 1 to 9, characterized in that: Along the axial direction of the cylindrical battery, there is a gap between the convex portion and the concave portion; The height of the gap is h, 0.1 mm ≤ h ≤ 0.3 mm.

11. The cylindrical battery according to any one of claims 1 to 10, characterized in that: When viewed along the axial direction of the cylindrical battery, the second portion surrounds the first portion.

12. The cylindrical battery according to any one of claims 1 to 10, characterized in that: When viewed along the axial direction of the cylindrical battery, the first portion surrounds the second portion.

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

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

Images