Cylindrical battery, battery pack and electric device

Abstract

A cylindrical battery (100), a battery pack (200) and an electric device (300). The cylindrical battery (100) comprises a casing (10), an electrode assembly (20) and an upper cover assembly (30). The casing (10) has an accommodating cavity (13), and the casing (10) comprises a side wall (11) and a bottom wall (12) that are connected to each other. The electrode assembly (20) is disposed in the accommodating cavity (13), and the electrode assembly (20) and the bottom wall (12) are arranged in the axial direction of the cylindrical battery (100). The upper cover assembly (30) is disposed on the side of the electrode assembly (20) facing away from the bottom wall (12), and is connected to the side wall (11) and the electrode assembly (20). The side wall (11) comprises a first part (111) and a second part (112) that are connected to each other, wherein the first part (111) and the second part (112) are arranged in the axial direction, the first part (111) is connected to the upper cover assembly (30), and the second part (112) is connected to the bottom wall (12). The thickness of the second part (112) is greater than that of the first part (111), and / or the rigidity of the second part (112) is greater than that of the first part (111), thus being conducive to enhancing the deformation resistance of the casing (10) and improving the safety and reliability of the cylindrical battery (100).

Description

Cylindrical batteries, battery packs and electrical devices Technical Field

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

[0002] With the rapid development of the lithium battery industry, its application in electric vehicles, electric bicycles, and power tools has become an inevitable trend. Cylindrical batteries, due to their advantages such as good packability and high stability, are highly favored and are increasingly being used in various complex scenarios. However, during the transportation and use of cylindrical batteries, they face risks such as drops or vibrations, affecting their safety and reliability.

[0003] Summary of the Invention

[0004] In view of the above situation, it is necessary to provide a cylindrical battery that improves the deformation resistance of the casing and reduces the loss of energy density.

[0005] Embodiments of this application provide a cylindrical battery, including a housing, an electrode assembly, and a top cover assembly. The housing has a receiving cavity and includes interconnected sidewalls and a bottom wall. The electrode assembly is disposed in the receiving cavity, and the electrode assembly and the bottom wall are arranged along the axial direction of the cylindrical battery. The top cover assembly is disposed on the side of the electrode assembly opposite to the bottom wall and is connected to the sidewall. The sidewall includes an interconnected first portion and a second portion, which are arranged axially. The first portion is connected to the top cover assembly, and the second portion is connected to the bottom wall. The cylindrical battery also satisfies at least one of conditions a and b: a) the thickness of the first portion is defined as T1, the thickness of the second portion is defined as T2, and T2 > T1; b) the stiffness of the second portion is greater than the stiffness of the first portion.

[0006] In the cylindrical battery of this application, the thickness T2 of the second part on the side wall connected to the bottom wall is greater than the thickness T1 of the first part on the side wall connected to the top cover assembly. Increasing the thickness of the second part on the side wall, which is prone to wear or collision, and / or making the stiffness of the second part greater than that of the first part, is beneficial to improving the shell's resistance to deformation and improving the safety and reliability of the cylindrical battery.

[0007] In one or more embodiments of this application, 1.3≤T2 / T1≤3, which helps to reduce the risk of casing deformation and improve the safety and reliability of cylindrical batteries.

[0008] In one or more embodiments of this application, 1.7≤T2 / T1≤2.7, which helps to reduce the risk of casing deformation, improve the safety and reliability of cylindrical batteries, and also reduce the impact on battery capacity.

[0009] In one or more embodiments of this application, 0.2mm≤T2≤1.5mm is beneficial to improving the structural strength of the second part, reducing the risk of deformation or damage to the second part, improving the safety and reliability of the cylindrical battery, and reducing the impact on battery capacity.

[0010] In one or more embodiments of this application, the electrode assembly includes a first electrode, a second electrode, and a separator, with the separator disposed between the first and second electrodes; along the axial direction, the separator extends beyond the first electrode, and the second electrode extends beyond the separator; along the axial direction, the end of the first portion extends beyond the end of the first electrode, or the end of the first portion is flush with the end of the first electrode, which helps to reduce the influence of the second portion on the ion insertion / extraction of the cathode active material of the electrode assembly, thereby improving the energy density and electrochemical performance of the cylindrical battery.

[0011] In one or more embodiments of this application, the length of the second part is defined as L along the axial direction, where 2mm≤L≤4mm. This helps to reduce the risk of casing deformation, improve the safety and reliability of the cylindrical battery, and improve the energy density and electrochemical performance of the cylindrical battery.

[0012] In one or more embodiments of this application, the thickness of the bottom wall is defined as T3 along the axial direction, where T3 > T1. This is beneficial for improving the structural strength and stiffness of the bottom wall, reducing the risk of deformation or damage to the bottom wall, and improving the safety and reliability of the cylindrical battery.

[0013] In one or more embodiments of this application, 0.5≤T2 / T3≤1 is beneficial to improving the deformation resistance of the bottom wall and enhancing the safety and reliability of the cylindrical battery.

[0014] In one or more embodiments of this application, the casing is the negative electrode of the cylindrical battery, and the thickness T3 of the bottom wall satisfies 0.4mm≤T3≤1.2mm, which is beneficial to both reduce the risk of casing deformation and reduce the impact of bottom wall thickness on the energy density of the cylindrical battery.

[0015] In one or more embodiments of this application, the casing is the negative electrode of a cylindrical battery, and the casing material includes steel.

[0016] In one or more embodiments of this application, the casing is the positive electrode of the cylindrical battery, and the thickness T3 of the bottom wall satisfies 0.8mm≤T3≤2mm, which is beneficial to both reduce the risk of casing deformation and reduce the impact of bottom wall thickness on the energy density of the cylindrical battery.

[0017] In one or more embodiments of this application, the casing is the positive electrode of a cylindrical battery, and the casing material includes aluminum.

[0018] In one or more embodiments of this application, the housing further includes an arc portion that connects the second part and the bottom wall. The arc portion helps to reduce stress concentration in the connection area between the second part and the bottom wall, reduces the risk of deformation or damage in the connection area between the second part and the bottom wall, and improves the safety and reliability of the cylindrical battery.

[0019] In one or more embodiments of this application, the radius of the outer contour of the arc portion is defined as R, where 0.7mm≤R≤1.5mm. This is beneficial for improving the structural strength and stiffness of the arc portion region, reducing the risk of stress concentration, deformation, or damage in this region, and improving the safety and reliability of the cylindrical battery.

[0020] Embodiments of this application also provide a battery pack, including the cylindrical battery of any of the foregoing embodiments.

[0021] In the aforementioned battery pack, the thickness T2 of the second part connecting the bottom wall to the side wall of the cylindrical battery is greater than the thickness T1 of the first part connecting the top cover assembly to the side wall. Increasing the thickness of the second part on the side wall, which is prone to wear or collision, and / or making the stiffness of the second part greater than that of the first part, helps to reduce the risk of casing deformation, improve the safety and reliability of the cylindrical battery, and reduce the impact of casing deformation on the battery pack.

[0022] Embodiments of this application also provide an electrical device, including the cylindrical battery or battery pack of any of the foregoing embodiments.

[0023] In the aforementioned electrical equipment, the thickness T2 of the second part connecting the bottom wall to the side wall of the cylindrical battery is greater than the thickness T1 of the first part connecting the top cover assembly to the side wall. Increasing the thickness of the second part on the side wall, which is prone to wear or collision, and / or making the stiffness of the second part greater than that of the first part, helps to reduce the risk of casing deformation, improve the safety and reliability of the cylindrical battery, and reduce the impact of casing deformation on the electrical equipment. Attached Figure Description

[0024] Figure 1 is a schematic diagram of the structure of a cylindrical battery in one embodiment of this application.

[0025] Figure 2 is an exploded view of a cylindrical battery in one embodiment of this application.

[0026] Figure 3 is a cross-sectional view of a cylindrical battery in one embodiment of this application.

[0027] Figure 4 is a partial structural cross-sectional view of a cylindrical battery in one embodiment of this application.

[0028] Figure 5 is a magnified view of region V in Figure 4.

[0029] Figure 6 is a schematic diagram of the battery pack structure in one embodiment of this application.

[0030] Figure 7 is a schematic diagram of the structure of the electrical equipment in one embodiment of this application.

[0031] Explanation of main component symbols

[0032] 100 cylindrical batteries

[0033] Casing 10

[0034] Side wall 11

[0035] Part 111

[0036] Part Two, 112

[0037] Transition section 114

[0038] Bottom wall 12

[0039] Receiving cavity 13

[0040] Arc 14

[0041] Electrode assembly 20

[0042] First film 21

[0043] First kneading part 211

[0044] Second pole piece 22

[0045] Second kneading flat section 221

[0046] Diaphragm 23

[0047] Top cover assembly 30

[0048] First insulating component 41

[0049] Axis 80

[0050] Battery pack 200

[0051] 300 electrical appliances

[0052] Axial X

[0053] The following detailed description, in conjunction with the accompanying drawings, will further illustrate this application. Detailed Implementation

[0054] The technical solutions of the embodiments of this application will be described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments.

[0055] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0056] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0057] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0058] In the description of the embodiments of this application, the term "perpendicular" is used to describe the ideal state between two components. In actual production or use, two components may exist in a state that is approximately perpendicular. For example, combined with numerical description, perpendicular can refer to the angle between two straight lines within the range of 90±10°, perpendicular can also refer to the dihedral angle between two planes within the range of 90°±10°, and perpendicular can also refer to the angle between a straight line and a plane within the range of 90±10°. The two components described as "perpendicular" do not have to be absolutely straight lines or planes, but can be approximately straight lines or planes. From a macroscopic perspective, if the overall extension direction is a straight line or plane, the component can be considered a "straight line" or "plane".

[0059] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. Where there is no conflict, the various embodiments in this application can be combined with each other.

[0060] It should be noted that the thickness, length, width, and other dimensions of various components in the embodiments of this application shown in the accompanying drawings, as well as the overall thickness, length, width, and other dimensions of the integrated device, are merely illustrative examples and should not constitute any limitation on this application.

[0061] Embodiments of this application provide a cylindrical battery, including a housing, an electrode assembly, and a top cover assembly. The housing has a receiving cavity and includes interconnected sidewalls and a bottom wall. The electrode assembly is disposed in the receiving cavity, and the electrode assembly and the bottom wall are arranged along the axial direction of the cylindrical battery. The top cover assembly is disposed on the side of the electrode assembly opposite to the bottom wall and is connected to the sidewall. The sidewall includes an interconnected first portion and a second portion, which are arranged axially. The first portion is connected to the top cover assembly, and the second portion is connected to the bottom wall. The thickness of the first portion is defined as T1, the thickness of the second portion as T2, where T2 > T1; and / or, the stiffness of the second portion is greater than the stiffness of the first portion.

[0062] In the cylindrical battery of this application, the thickness T2 of the second part on the side wall connected to the bottom wall is greater than the thickness T1 of the first part on the side wall connected to the top cover assembly. Increasing the thickness of the second part on the side wall, which is prone to wear or collision, and / or making the stiffness of the second part greater than that of the first part, is beneficial to improving the shell's resistance to deformation and improving the safety and reliability of the cylindrical battery.

[0063] The embodiments of this application will be further described below with reference to the accompanying drawings.

[0064] As shown in Figures 1 to 3, an embodiment of this application provides a cylindrical battery 100, including a housing 10, an electrode assembly 20, and a top cover assembly 30. The housing 10 has a receiving cavity 13 and includes a side wall 11 and a bottom wall 12 connected to each other. The electrode assembly 20 is disposed in the receiving cavity 13, and the electrode assembly 20 and the bottom wall 12 are arranged along the axial direction X of the cylindrical battery 100. The electrode assembly 20 is connected to the bottom wall 12. The top cover assembly 30 is disposed on the side of the electrode assembly 20 opposite to the bottom wall 12 and connects the side wall 11 and the electrode assembly 20. The electrode assembly 20 and the bottom wall 12 are electrically connected, and the electrode assembly 20 and the top cover assembly 30 are electrically connected. The top cover assembly 30 and the side wall 11 are insulated from each other. The top cover assembly 30 and the housing 10 form the positive and negative terminals of the cylindrical battery 100. The cylindrical battery 100 is electrically connected to an external device through the top cover assembly 30 and the housing 10, thereby enabling charging or discharging.

[0065] Here, the axial direction X refers to the direction from the upper cover assembly 30 toward the bottom wall 12.

[0066] In one embodiment, the electrode assembly 20 includes a first electrode 21, a second electrode 22, and a diaphragm 23, with the diaphragm 23 disposed between the first electrode 21 and the second electrode 22. The first electrode 21, the diaphragm 23, and the second electrode 22 are wound together. One of the first electrode 21 and the second electrode 22 is a positive electrode, and the other is a negative electrode.

[0067] In one embodiment, the first electrode 21 is electrically connected to the upper cover assembly 30, and the second electrode 22 is electrically connected to the bottom wall 12.

[0068] In one embodiment, the diaphragm 23 extends beyond the second electrode 22 in a direction opposite to the axial direction X, and the first electrode 21 extends beyond the diaphragm 23. The portion of the first electrode 21 extending beyond the diaphragm 23 is flattened to form a first flattened portion 211, which is connected to the upper cover assembly 30. By providing the first flattened portion 211 connected to the upper cover assembly 30, the connection stability between the first electrode 21 and the upper cover assembly 30 is improved.

[0069] In one embodiment, along the axial direction X, the separator 23 extends beyond the first electrode 21, and the second electrode 22 extends beyond the separator 23. The portion of the second electrode 22 extending beyond the separator 23 is flattened to form a second flattened portion 221, which is connected to the bottom wall 12. By providing the second flattened portion 221 connected to the bottom wall 12, the connection process between the second electrode 22 and the bottom wall 12 is simplified, improving the assembly efficiency of the cylindrical battery 100 and enhancing the connection stability between the second electrode 22 and the bottom wall 12. In one embodiment, the second flattened portion 221 and the bottom wall 12 are welded together.

[0070] As shown in Figures 3 to 5, in one embodiment, the sidewall 11 includes a first part 111 and a second part 112 that are connected to each other. The first part 111 and the second part 112 are arranged along the axial direction X. The first part 111 is connected to the upper cover assembly 30, and the second part 112 is connected to the bottom wall 12.

[0071] In one embodiment, the thickness of the first portion 111 is defined as T1, and the thickness of the second portion 112 is defined as T2, where T2 > T1. The thickness T2 of the second portion 112 on the sidewall 11, which connects to the bottom wall 12, is greater than the thickness T1 of the first portion 111 on the sidewall 11, which connects to the top cover assembly 30. Increasing the thickness of the second portion 112 on the sidewall 11, which is prone to wear or collision, helps to reduce the risk of deformation of the casing 10 and improves the safety and reliability of the cylindrical battery 100.

[0072] Taking the second part 112 as an example, the thickness is measured as follows: along the axial direction X, the second part 112 is divided into 10 equal unit segments. The thickness of all unit segments is measured with calipers, and then the average value of all thicknesses is taken as the thickness of the second part 112. The thickness of the first part 111 and the thickness of the bottom wall 12 described below are also measured using the aforementioned method, and will not be repeated here.

[0073] In one embodiment, the stiffness of the second part 112 is greater than that of the first part 111, which helps to reduce the risk of deformation of the casing 10 and improve the safety and reliability of the cylindrical battery 100.

[0074] In one embodiment, the stiffness of the second portion 112 is increased by increasing its thickness, thereby making the stiffness of the second portion 112 greater than that of the first portion 111.

[0075] In one embodiment, the stiffness of the second portion 112 is increased by coating the surface of the second portion 112 with a metal layer or a polymer layer, making the stiffness of the second portion 112 greater than that of the first portion 111. In one embodiment, the metal layer is formed on the inner wall of the second portion 112 by electroplating, which is beneficial for increasing the stiffness of the second portion 112.

[0076] In one embodiment, 1.3≤T2 / T1≤3 is beneficial to reducing the risk of deformation of the casing 10, improving the safety and reliability of the cylindrical battery 100, and reducing the impact of the sidewall 11 thickness on the energy density of the cylindrical battery 100.

[0077] In one embodiment, 1.7≤T2 / T1≤2.7 is beneficial to reduce the risk of deformation of the casing 10, improve the safety and reliability of the cylindrical battery 100, and reduce the impact of the sidewall 11 thickness on the energy density of the cylindrical battery 100.

[0078] In one embodiment, the value of T2 / T1 is any one of 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9 and 3, which is beneficial to reduce the risk of deformation of the casing 10, improve the safety and reliability of the cylindrical battery 100, and reduce the impact of the sidewall 11 thickness on the energy density of the cylindrical battery 100.

[0079] In one embodiment, 0.2mm≤T2≤1.5mm is beneficial to improving the structural strength of the second part 112, reducing the risk of deformation or breakage of the second part 112, improving the safety and reliability of the cylindrical battery 100, and also reducing the impact on battery capacity. Optionally, the thickness T2 of the second part 112 is 0.2mm, 0.22mm, 0.24mm, 0.26mm, 0.28mm, 0.3mm, 0.32mm, 0.34mm, 0.36mm, 0.38mm, 0.4mm, 0.42mm, 0.44mm, 0.46mm, 0.48mm, 0.5mm, 0.52mm, 0.54mm, 0.56mm, 0.58mm, 0.6mm, 0.62mm, 0.64mm, 0.66mm, 0.68mm, 0.7mm, 0.72mm, 0.74mm, 0.76mm, 0.78mm, 0.8mm, 0.82mm. Any one of the following: 0.84mm, 0.86mm, 0.88mm, 0.9mm, 0.92mm, 0.94mm, 0.96mm, 0.98mm, 1mm, 1.02mm, 1.04mm, 1.06mm, 1.08mm, 1.1mm, 1.12mm, 1.14mm, 1.16mm, 1.18mm, 1.2mm, 1.22mm, 1.24mm, 1.26mm, 1.28mm, 1.3mm, 1.32mm, 1.34mm, 1.36mm, 1.38mm, 1.4mm, 1.42mm, 1.44mm, 1.46mm, 1.48mm, and 1.5mm.

[0080] In one embodiment, the thickness of the bottom wall 12 along the axial direction X is defined as T3, where T3 > T1. This is beneficial for improving the structural strength and stiffness of the bottom wall 12, reducing the risk of deformation or damage to the bottom wall 12, improving the deformation resistance of the bottom wall 12, and improving the safety and reliability of the cylindrical battery 100.

[0081] In one embodiment, 0.5≤T2 / T3≤1 is beneficial to improving the deformation resistance of the bottom wall 12 and improving the safety and reliability of the cylindrical battery 100.

[0082] In one embodiment, the value of T2 / T3 is any one of 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95 and 1, which is beneficial to improve the deformation resistance of the bottom wall 12 and improve the safety and reliability of the cylindrical battery 100.

[0083] In one embodiment, the casing 10 is made of metal, which helps to improve the current carrying capacity of the cylindrical battery 100, reduce the risk of deformation or damage to the casing 10, improve the deformation resistance of the casing 10, and improve the reliability of the cylindrical battery 100.

[0084] In one embodiment, the casing 10 serves as the negative electrode of the cylindrical battery 100, and the thickness T3 of the bottom wall 12 satisfies 0.4mm ≤ T3 ≤ 1.2mm. This balances the risk of casing 10 deformation with the impact of the bottom wall 12 thickness on the energy density of the cylindrical battery 100. Optionally, the thickness T3 of the bottom wall 12 can be any one of 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, 1.1mm, and 1.2mm. In one embodiment, the casing 10 is made of steel.

[0085] In one embodiment, the casing 10 serves as the positive electrode of the cylindrical battery 100, and the thickness T3 of the bottom wall 12 satisfies 0.8mm ≤ T3 ≤ 2mm. This balances the risk of casing 10 deformation with the impact of the bottom wall 12 thickness on the energy density of the cylindrical battery 100. Optionally, the thickness T3 of the bottom wall 12 can be any one of 0.8mm, 0.9mm, 1mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, 1.6mm, 1.7mm, 1.8mm, 1.9mm, and 2mm. In one embodiment, the casing 10 is made of aluminum.

[0086] In one embodiment, along the axial direction X, the end of the first portion 111 extends beyond the end of the first electrode 21, or the end of the first portion 111 is flush with the end of the first electrode 21. This is beneficial to reduce the influence of the second portion 112 on the ion insertion / extraction of the cathode active material of the electrode assembly 20, thereby increasing the energy density of the cylindrical battery 100. It is also beneficial to reduce the influence of the second portion 112 on the expansion of the electrode assembly 20, thereby improving the electrochemical performance of the cylindrical battery 100.

[0087] In one embodiment, the length of the second part 112 along the axial direction X is L, 2mm≤L≤4mm, which helps to reduce the risk of deformation of the casing 10, improve the safety and reliability of the cylindrical battery 100, and help to improve the energy density and electrochemical performance of the cylindrical battery.

[0088] In one embodiment, the housing 10 further includes an arc portion 14, which connects the second part 112 and the bottom wall 12. The arc portion 14 helps to reduce stress concentration in the connection area between the second part 112 and the bottom wall 12, reduces the risk of deformation or damage in the connection area between the second part 112 and the bottom wall 12, and improves the safety and reliability of the cylindrical battery 100.

[0089] In one embodiment, the radius of the outer contour of the arc portion 14 is defined as R, where 0.7mm ≤ R ≤ 1.5mm. This is beneficial for improving the structural strength and rigidity of the arc portion 14 region, reducing the risk of stress concentration, deformation, or damage in this region, and improving the safety and reliability of the cylindrical battery 100. Optionally, the radius R of the outer contour of the arc portion 14 can be any one of 0.7mm, 0.8mm, 0.9mm, 1mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, and 1.5mm.

[0090] In one embodiment, the sidewall 11 further includes a transition portion 114, which is located along the axial direction X between the first portion 111 and the second portion 112 and connects the first portion 111 and the second portion 112.

[0091] In one embodiment, along the axial direction X, the thickness of the transition portion 114 gradually increases from the region connecting the first portion 111 to the region connecting the second portion 112, which helps to reduce the risk of stress concentration in the sidewall 11, improve the deformation resistance of the casing, and improve the safety and reliability of the cylindrical battery 100.

[0092] To verify the reliability of the cylindrical battery 100 in this application, multiple sets of embodiments and comparative examples were selected for roller testing, as follows:

[0093] Twelve identical cylindrical batteries were taken as examples, and these cylindrical batteries were the cylindrical batteries 100 described in any of the foregoing embodiments of this application.

[0094] Twelve identical cylindrical batteries were taken as comparative examples. The only difference between these cylindrical batteries and the cylindrical battery 100 in the previous embodiment is that the thickness of the second part is equal to the thickness of the first part.

[0095] In Examples 1-15 and Comparative Examples 1-3, the battery casings are made of steel and are negatively charged; in Examples 16-31 and Comparative Examples 4-6, the battery casings are made of aluminum and are positively charged.

[0096] The drum test method is as follows: the cylindrical battery is subjected to an octahedral drum test. The octahedral drum is custom-made, with the following dimensions: inscribed circle diameter of 230mm, length of 230mm, and wall thickness of 10mm. The test speed is 66 rpm, and the test time is 100 minutes.

[0097] After all the aforementioned sets of embodiments and comparative examples have been tested, the number of tests that passed and the number of tests that failed in each set of tests are counted.

[0098] The method for determining whether the test is passed is as follows: observe the shape of the second part and check the battery voltage before and after the test. If the shape of the second part remains unchanged before and after the test, and the battery terminal voltage remains essentially unchanged, the test is passed.

[0099] The method for determining if the test fails is as follows: observe the shape of the second part and check the battery voltage before and after the test. If the second part shrinks towards the battery axis after the test, and the battery terminal voltage is close to zero after the test, it can be determined that an internal short circuit has occurred, which means the test fails.

[0100] Table 1

[0101] As can be seen from the table above, the cylindrical battery 100 used in the embodiments of this application has good safety and reliability.

[0102] In summary, in the cylindrical battery 100 of this application, the thickness T2 of the second part 112 on the side wall 11 that connects to the bottom wall 12 is greater than the thickness T1 of the first part 111 on the side wall 11 that connects to the top cover assembly 30. Increasing the thickness of the second part 112 on the side wall 11 that is prone to wear or collision, and / or making the stiffness of the second part 112 greater than the stiffness of the first part 111, is beneficial to improving the deformation resistance of the casing 10 and improving the safety and reliability of the cylindrical battery 100.

[0103] As shown in Figure 9, an embodiment of this application also provides a battery pack 200, including the cylindrical battery 100 in any of the foregoing embodiments.

[0104] In the aforementioned battery pack 200, the thickness T2 of the second part 112 on the side wall 11 of the cylindrical battery 100, which is connected to the bottom wall 12, is greater than the thickness T1 of the first part 111 on the side wall 11, which is connected to the top cover assembly 30. Increasing the thickness of the second part 112 on the side wall 11, which is prone to wear or collision, and / or making the stiffness of the second part 112 greater than that of the first part 111, helps to reduce the risk of deformation of the casing 10, improve the safety and reliability of the cylindrical battery 100, and reduce the impact of casing 10 deformation on the battery pack 200.

[0105] As shown in Figure 10, an embodiment of this application also provides an electrical device 300, including the cylindrical battery 100 or battery pack 200 in any of the foregoing embodiments.

[0106] In the aforementioned electrical equipment 300, the thickness T2 of the second part 112 on the side wall 11 of the cylindrical battery 100 that connects to the bottom wall 12 is greater than the thickness T1 of the first part 111 on the side wall 11 that connects to the top cover assembly 30. Increasing the thickness of the second part 112 on the side wall 11, which is prone to wear or collision, and / or making the rigidity of the second part 112 greater than that of the first part 111, helps to reduce the risk of deformation of the casing 10, improve the safety and reliability of the cylindrical battery 100, and reduce the impact of casing 10 deformation on the electrical equipment 300.

[0107] In one embodiment, the electrical equipment 300 includes, but is not limited to, electric vehicles, drones, electric two-wheelers, home appliances, consumer electronics, and power tools.

[0108] In addition, those skilled in the art may make other changes within the spirit of this application. Of course, all such changes made in accordance with the spirit of this application should be included within the scope disclosed in this application.

Claims

1. A cylindrical battery, characterized in that, include: A housing having a receiving cavity, the housing including interconnected sidewalls and a bottom wall; An electrode assembly is disposed in the receiving cavity, and the electrode assembly and the bottom wall are arranged along the axial direction of the cylindrical battery; A top cover assembly is disposed on the side of the electrode assembly opposite to the bottom wall and is connected to the side wall; The sidewall includes a first part and a second part that are connected to each other, the first part and the second part being arranged along the axial direction, the first part being connected to the upper cover assembly, and the second part being connected to the bottom wall; The cylindrical battery also satisfies at least one of conditions a and b: a. Define the thickness of the first part as T1, and the thickness of the second part as T2, where T2 > T1; b. The stiffness of the second part is greater than that of the first part.

2. The cylindrical battery as described in claim 1, characterized in that, 1.3≤T2 / T1≤3.

3. The cylindrical battery as described in claim 2, characterized in that, 1.7≤T2 / T1≤2.

7.

4. The cylindrical battery as described in claim 1 or 2, characterized in that, 0.2mm≤T2≤1.5mm.

5. The cylindrical battery according to any one of claims 1 to 4, characterized in that, The electrode assembly includes a first electrode, a second electrode, and a diaphragm, wherein the diaphragm is disposed between the first electrode and the second electrode. Along the axial direction, the diaphragm extends beyond the first electrode, and the second electrode extends beyond the diaphragm; Along the axial direction, the end of the first portion extends beyond the end of the first electrode, or the end of the first portion is flush with the end of the first electrode.

6. The cylindrical battery according to any one of claims 1 to 5, characterized in that, Along the axial direction, the length of the second part is defined as L, where 2mm ≤ L ≤ 4mm.

7. The cylindrical battery according to any one of claims 1 to 6, characterized in that, Along the axial direction, the thickness of the bottom wall is defined as T3, where 0.5 ≤ T2 / T3 ≤ 1.

8. The cylindrical battery according to any one of claims 1 to 7, characterized in that, The casing serves as the negative electrode of the cylindrical battery, and the thickness T3 of the bottom wall satisfies 0.4mm ≤ T3 ≤ 1.2mm; or, The casing is the positive electrode of the cylindrical battery, and the thickness T3 of the bottom wall satisfies 0.8mm≤T3≤2mm.

9. The cylindrical battery according to any one of claims 1 to 8, characterized in that, The casing serves as the negative electrode of the cylindrical battery, and the casing is made of steel; or, The casing is the positive electrode of the cylindrical battery, and the casing is made of aluminum.

10. The cylindrical battery according to any one of claims 1 to 9, characterized in that, The housing also includes an arcuate portion that connects the second part and the bottom wall; The radius of the outer contour of the arc portion is defined as R, where 0.7mm ≤ R ≤ 1.5mm.

11. A battery pack, characterized in that, Including the cylindrical battery as described in any one of claims 1 to 10.

12. An electrical appliance, characterized in that, Includes a cylindrical battery as described in any one of claims 1 to 10, or a battery pack as described in claim 11.

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