Cylindrical secondary battery, battery pack, and electric device

Abstract

A cylindrical secondary battery, a battery pack, and an electric device. The cylindrical secondary battery comprises a housing, an electrode assembly, a first electrode terminal, and a current cut-off device; the current cut-off device comprises a connection plate, an explosion-proof piece, and a first insulating member; the connection plate comprises a first portion and a second portion; the explosion-proof piece comprises a third portion and a fourth portion; and the current cut-off device is electrically connected to the first electrode terminal and the electrode assembly. In the axial direction of the cylindrical secondary battery, at least part of the first insulating member is arranged between the first portion and the fourth portion, and the melting point of the first insulating member is t1, wherein t1≥300°C. The first insulating member has a high melting point, and is not prone to melting in a high-temperature environment, which is beneficial for maintaining good insulation between the first portion and the fourth portion, thereby reducing the risk of failure of current cut-off devices, and improving the use safety performance of cylindrical secondary batteries, battery packs, and electric devices.

Description

Cylindrical secondary battery, battery pack and electric device

[0001] This application claims priority to the Chinese patent application No. 202410895935.4, filed on July 4, 2024, and entitled "Cylindrical secondary battery, battery pack and electric device", the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0002] The present application relates to the technical field of energy storage, in particular to a cylindrical secondary battery, a battery pack and an electric device. BACKGROUND

[0003] Secondary batteries have high energy density, long service life and other characteristics, and are widely used. A current interrupt device (CID) is generally provided in the shell of the secondary battery. When the pressure in the shell of the secondary battery is too large, the CID can disconnect the charging and discharging circuit of the secondary battery, thereby providing safety protection for the secondary battery.

[0004] With the continuous enrichment of the application scenarios of secondary batteries, in some application scenarios, the secondary batteries have a larger capacity to provide high power and long endurance for users. However, with the increase of the capacity of the secondary battery, more heat will be released under abnormal working conditions, increasing the probability of failure of the existing CID and reducing the safety of the use of the secondary battery. SUMMARY

[0005] The purpose of the embodiments of the present application is to provide a cylindrical secondary battery, a battery pack and an electric device to improve the safety performance in use.

[0006] In a first aspect, the present application provides a cylindrical secondary battery, comprising: a shell; an electrode assembly arranged in the shell; a first electrode terminal insulatedly connected with the shell; a current interrupt device comprising a connecting plate, a rupture disc and a first insulating piece, the connecting plate and the rupture disc being arranged along the axial direction of the cylindrical secondary battery; wherein the connecting plate comprises a first part and a second part, the first part surrounds the second part, and the first part is electrically connected with the electrode assembly; the rupture disc comprises a third part and a fourth part, along the axial direction, the projection of the fourth part surrounds the projection of the third part, the fourth part is electrically connected with the first electrode terminal, and the second part is electrically connected with the third part; along the axial direction, at least part of the first insulating piece is arranged between the first part and the fourth part; the melting point of the first insulating piece is t1, and t1≥300℃. When the cylindrical secondary battery appears in adverse working conditions such as external short circuit, the temperature in the shell rises rapidly, the melting point of the first insulating piece is relatively high, and the first insulating piece is not easy to melt in a high temperature environment, which is conducive to the first insulating piece to maintain good insulation between the first part and the fourth part, and reduces the risk of failure of the current interrupt device.

[0007] In one or more embodiments, t1≥500℃. The first insulating piece has a higher melting point and can withstand higher temperatures, which is conducive to maintaining good insulation between the first part and the fourth part and reducing the risk of failure of the current interruption device.

[0008] In one or more embodiments, t1≥800℃. The first insulating piece has a higher melting point and can withstand higher temperatures, which is conducive to maintaining good insulation between the first part and the fourth part and reducing the risk of failure of the current interruption device.

[0009] In one or more embodiments, t1≤1500℃. The first insulating piece meets the high-temperature resistance (1500℃) condition, the material is easy to select and prepare, and the cylindrical secondary battery is easy to process and produce.

[0010] In one or more embodiments, the material of the first insulating piece includes an oxide ceramic or a non-oxide ceramic; the oxide ceramic includes at least one of Al2O3, ZrO, MgO, CaO, B2O3, ThO2, Cr2O3, SiO2, BeO, or 3Al2O3·2SiO2; and the non-oxide ceramic includes at least one of a carbide ceramic, a boride ceramic, a nitride ceramic, or a silicide ceramic. The above-mentioned materials have good high-temperature resistance and are not easy to melt in a high-temperature environment, which is conducive to the first insulating piece maintaining good insulation between the first part and the fourth part and reducing the risk of failure of the current interruption device.

[0011] In one or more embodiments, the first insulating piece includes a fifth part, which is disposed between the first part and the fourth part along the axial direction; the thickness of the fifth part is H1, and the thickness of the second part is H2, and 1.5≤H1 / H2≤5. By using the above-mentioned ratio range of H1 and H2, after the rupture disc is flipped, if the second part generates a free and separated residue during the process of breaking the first part, the residue falls between the first part and the fourth part, and since the thickness of the fifth part of the first insulating piece is greater than the thickness of the second part, the thickness of the residue is less than the spacing between the first part and the fourth part, the residue is not easy to be electrically connected to the first part and the fourth part at the same time, and the rupture disc and the connecting plate are connected again; if the value of H1 / H2 is too large, it is easy to cause the length of the cylindrical secondary battery to increase, and the energy density is lost.

[0012] In one or more embodiments, 0.3mm≤H1≤0.7mm. The value range of H1 is conducive to good insulation of the first part and the fourth part.

[0013] In one or more embodiments, the shell includes a top wall having a through hole; the first insulating member includes a sixth portion surrounding the fifth portion, at least a part of the sixth portion is arranged in the through hole, which is conducive to the sixth portion limiting the fifth portion in a direction perpendicular to the axial direction of the cylindrical secondary battery, and is conducive to reducing the risk of the fifth portion being loosened between the first portion and the fourth portion.

[0014] In one or more embodiments, further comprising: a sealing member, the cylindrical secondary battery is a cylindrical secondary battery; the top wall includes a first extension portion extending from a hole wall of the through hole in a radial direction of the cylindrical secondary battery; a part of the first electrode terminal is arranged on a side of the first extension portion away from the electrode assembly; and in the axial direction, the sealing member is arranged between the part of the first electrode terminal and the first extension portion, which is conducive to improving the sealing performance between the first electrode terminal and the top wall.

[0015] In one or more embodiments, the fourth portion includes a first segment; the first segment extends in the radial direction of the cylindrical secondary battery, and the first segment is connected to the first electrode terminal; and in the axial direction, at least a part of the sealing member is arranged between the first segment and the first extension portion. The first segment extends in the radial direction of the cylindrical secondary battery and is connected to the first electrode terminal, and at least a part of the sealing member is arranged between the first segment and the first extension portion, which is conducive to forming a good seal between the fourth portion of the rupture disc and the first extension portion of the top wall.

[0016] In one or more embodiments, the fourth portion includes a second segment extending in the axial direction and connected to the first segment; and in the radial direction of the cylindrical secondary battery, a part of the sixth portion of the first insulating member is arranged between the second segment and the first extension portion. The sixth portion of the first insulating member has a high melting point, and is not easy to melt in a high-temperature environment, which is conducive to maintaining good insulation between the second segment of the rupture disc and the first extension portion of the top wall, and reducing the risk of failure of the current cut-off device. The first segment extends in the radial direction of the cylindrical secondary battery, the second segment extends in the axial direction of the cylindrical secondary battery and is connected to the first electrode terminal, which is conducive to forming a stable electrical connection structure of the fourth portion of the rupture disc in two directions of the first electrode terminal.

[0017] In one or more embodiments, in the axial direction, the sixth portion exceeds the first extension portion. In a high-temperature environment, the sealing member has the possibility of melting, the sixth portion of the first insulating member has a high melting point and is not easy to melt, and the sixth portion is easy to form a support between the first extension portion of the shell and the first segment of the rupture disc, so that the first extension portion and the first segment are arranged in a spaced manner, maintaining good insulation between the first extension portion and the first segment of the rupture disc, and reducing the risk of failure of the current cut-off device.

[0018] In one or more embodiments, the top wall comprises a main body portion surrounding the first extension portion, the main body portion has a thickness H3, the first extension portion has a thickness H4, and 0.1≤H4 / H3≤0.5. With the above range of the ratio of H4 and H3, the thickness of the first extension portion is reduced, thereby reducing the length of the cylindrical secondary battery and improving the volumetric energy density of the cylindrical secondary battery, while the first extension portion provides a good supporting force to the first electrode terminal.

[0019] In one or more embodiments, 1mm≤H3≤4mm. With the above range of the thickness H3, the main body portion has a good impact resistance, thereby facilitating the retention of the electrode assembly in the housing in a bumpy environment.

[0020] In one or more embodiments, the material of the sealing member comprises fluororubber, the fluororubber has good corrosion resistance and high temperature resistance, thereby improving the sealing effect of the cylindrical secondary battery and reducing the probability of electrolyte leakage.

[0021] In one or more embodiments, the sealing member has a thickness H5, and 0.5mm≤H5≤2.3mm. With the above range of the thickness H5 of the fluororubber, the sealing member has a good sealing effect and a thin thickness, thereby reducing the length of the cylindrical secondary battery and improving the volumetric energy density of the cylindrical secondary battery.

[0022] In one or more embodiments, the top wall further comprises a second extension portion, the cylindrical secondary battery is a cylindrical secondary battery, the top wall comprises the second extension portion, the main body portion and the second extension portion are arranged along an axial direction of the cylindrical secondary battery, the second extension portion comprises a seventh portion, the seventh portion extends from the main body portion along the axial direction of the cylindrical secondary battery, and the second insulating member comprises a ninth portion, the ninth portion extends from the seventh portion along the axial direction of the cylindrical secondary battery and along a radial direction of the cylindrical secondary battery, the ninth portion is arranged between the seventh portion and the first electrode terminal, and the seventh portion and the first electrode terminal are insulated and connected.

[0023] In one or more embodiments, the second extension portion further comprises an eighth portion, the eighth portion extends from the seventh portion along a direction opposite to the radial direction of the cylindrical secondary battery, the second insulating member further comprises a tenth portion, the tenth portion extends from the ninth portion along the direction opposite to the radial direction of the cylindrical secondary battery and along the axial direction of the cylindrical secondary battery, the tenth portion is arranged between the eighth portion and the first electrode terminal, and the eighth portion and the first electrode terminal are insulated and connected.

[0024] In one or more embodiments, the cylindrical secondary battery is a cylindrical secondary battery, a diameter of the cylindrical secondary battery is D, 25mm≤D≤65mm; and / or, a length of the cylindrical secondary battery is L, 40mm≤L≤250mm. The cylindrical secondary battery adopts the diameter and length range as described above, which is easy to prepare a cylindrical secondary battery with large capacity, so as to provide large power and long endurance for users.

[0025] In a second aspect, the present application provides a battery pack comprising the cylindrical secondary battery as described above.

[0026] In a third aspect, the present application provides an electric device comprising the cylindrical secondary battery or the battery pack as described above.

[0027] The cylindrical secondary battery, the battery pack and the electric device provided by the embodiments of the present application, the cylindrical secondary battery comprises a shell, an electrode assembly, a first electrode terminal and a current cut-off device, the current cut-off device comprises a connecting plate, a rupture disc and a first insulating piece, the connecting plate comprises a first part and a second part, the first part surrounds the second part, the rupture disc comprises a third part and a fourth part, along the axial direction, a projection of the fourth part surrounds a projection of the third part, the first part is electrically connected to the electrode assembly, the second part and the third part are electrically connected, and the fourth part is electrically connected to the first electrode terminal, so that the current cut-off device is electrically connected to the first electrode terminal and the electrode assembly. Along the axial direction, at least part of the first insulating piece is arranged between the first part and the fourth part, the melting point of the first insulating piece is t1, t1≥300℃, the melting point of the first insulating piece is relatively high, and the first insulating piece is not easy to melt in a high-temperature environment, which is conducive to the first insulating piece to maintain good insulation between the first part and the fourth part, reduces the risk of failure of the current cut-off device, and improves the use safety performance of the cylindrical secondary battery, the battery pack and the electric device.

[0028] Of course, it is not necessary for any product implementing the present application to achieve all the advantages described above. BRIEF DESCRIPTION OF DRAWINGS

[0029] The drawings described herein are used to provide further understanding of the present application, and form a part of the present application. The schematic embodiments of the present application and the descriptions thereof are used to explain the present application, and do not constitute an improper limitation on the present application.

[0030] FIG. 1 is a structural schematic diagram of a cylindrical secondary battery according to an embodiment of the present application;

[0031] FIG. 2 is a partial cross-sectional structural schematic diagram of a cylindrical secondary battery according to an embodiment of the present application;

[0032] FIG. 3 is an enlarged view of A in FIG. 2;

[0033] FIG. 4 is a structural schematic diagram of a first insulating piece of a cylindrical secondary battery according to an embodiment of the present application;

[0034] FIG. 5 is a cross-sectional structural schematic view of a first insulating member of a cylindrical secondary battery according to an embodiment of the present application;

[0035] FIG. 6 is a structural schematic view of a top wall of a cylindrical secondary battery according to an embodiment of the present application;

[0036] FIG. 7 is a structural schematic view of a top wall of a cylindrical secondary battery according to an embodiment of the present application;

[0037] FIG. 8 is a cross-sectional structural schematic view of a top wall of a cylindrical secondary battery according to an embodiment of the present application;

[0038] FIG. 9 is a structural schematic view of a second insulating member of a cylindrical secondary battery according to an embodiment of the present application;

[0039] FIG. 10 is a cross-sectional structural schematic view of a second insulating member of a cylindrical secondary battery according to an embodiment of the present application;

[0040] FIG. 11 is a structural schematic view of a connecting plate of a cylindrical secondary battery according to an embodiment of the present application;

[0041] FIG. 12 is a cross-sectional structural schematic view of a connecting plate of a cylindrical secondary battery according to an embodiment of the present application;

[0042] FIG. 13 is a structural schematic view of a rupture disk of a cylindrical secondary battery according to an embodiment of the present application;

[0043] FIG. 14 is a cross-sectional structural schematic view of a rupture disk of a cylindrical secondary battery according to an embodiment of the present application;

[0044] FIG. 15 is a structural schematic view of a battery pack according to an embodiment of the present application;

[0045] FIG. 16 is a structural schematic view of a first power consuming device according to an embodiment of the present application;

[0046] FIG. 17 is a structural schematic view of a second power consuming device according to an embodiment of the present application;

[0047] The reference signs are as follows: shell 10, top wall 11, through hole 110, main body part 111, first extension part 112, second extension part 113, seventh part 1131, eighth part 1132, side wall 12, electrode assembly 20, first electrode terminal 30, current cut-off device 40, connecting plate 41, first part 411, air vent hole 4111, second part 412, welding surface 4121, first annular groove 4122, explosion-proof sheet 42, third part 421, fourth part 422, first section 4221, second section 4222, second annular groove 4223, turnover body 423, first insulating part 43, fifth part 431, sixth part 432, sealing part 50, second insulating part 60, ninth part 61, tenth part 62; cylindrical secondary battery 100, battery pack 200, electric device 300; axial direction Y, radial direction X, axis L0. DETAILED DESCRIPTION

[0048] To make the objectives, technical solutions, and advantages of the present application clearer, further detailed description will be made to the present application with reference to the drawings and examples. Obviously, the described examples are only some of the examples of the present application, but not all the examples. All other examples obtained by those skilled in the art based on the examples in the present application shall fall within the scope of protection of the present application.

[0049] In the present application, unless specifically defined and limited, the terms “mounting”, “connecting”, “connecting”, “fixing” and the like should be understood in a broad sense, for example, can be fixed connection, can also be detachable connection, or integrally connected; can be mechanical connection, can also be electrical connection; can be directly connected, can also be indirectly connected through an intermediate medium, can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances. The term “and / or” used herein includes any and all combinations of one or more related listed items.

[0050] In the description of the embodiments of the present application, the technical terms “first”, “second” and the like are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of “multiple” is more than two, unless otherwise specifically limited.

[0051] In this paper, the reference to “embodiments” means that the specific features, structures or properties described in conjunction with the embodiments can be included in at least one embodiment of the present application. The phrase appears at various places in the specification does not necessarily refer to the same embodiment, nor is it independent or alternative to other embodiments. In the case of no conflict, the various embodiments in the present application can be combined with each other.

[0052] In the related art, the capacity of the cylindrical secondary battery is small, and the small-capacity cylindrical secondary battery releases less heat after short circuit, and when the gas pressure in the shell of the secondary battery is too large, the CID can disconnect the charge-discharge circuit of the secondary battery. For a large-capacity cylindrical secondary battery, more heat is released after short circuit, and the internal temperature is also higher, and the existing CID can have a high-temperature failure problem. The embodiments of the present application mainly improve the CID in order to improve the safety protection performance of the CID.

[0053] The shape of the cylindrical secondary battery in the present application is not particularly limited, as long as the purpose of the present application is achieved. In one or more embodiments, the cylindrical secondary battery is at least one of a cylindrical secondary battery, an elliptical secondary battery (cross section is an ellipse), a polygonal secondary battery (cross section is a polygon, including a regular polygonal secondary battery or an irregular polygonal secondary battery).

[0054] In order to better understand the present application, the cylindrical secondary battery of the embodiments of the present application will be described in detail below.

[0055] It should be noted that the sizes of various components in the embodiments of the present application shown in the drawings, and the sizes of the cylindrical secondary battery are only exemplary and should not constitute any limitation on the present application.

[0056] FIG. 1 is a schematic structural diagram of a cylindrical secondary battery according to an embodiment of the present application. As shown in FIG. 1, in a first aspect, the present application provides a cylindrical secondary battery 100, and the axis of the cylindrical secondary battery 100 is L0. The radial direction of the cylindrical secondary battery 100 is X, which is in the plane perpendicular to the axis L0, and the direction from the axis L0 to the outside of the cylindrical secondary battery 100. The axial direction of the cylindrical secondary battery 100 is Y, which is parallel to the axis L0 of the cylindrical secondary battery 100. The length of the cylindrical secondary battery 100 is L, and the diameter of the cylindrical secondary battery 100 is D.

[0057] In one or more embodiments, the diameter of the cylindrical secondary battery 100 is D, and 25mm≤D≤65mm; and / or, the length of the cylindrical secondary battery 100 is L, and 40mm≤L≤250mm. The cylindrical secondary battery 100 adopts the above-mentioned diameter and length range, which is easy to prepare a large-capacity cylindrical secondary battery 100, so as to be applicable to the application scenarios of the demand for large-capacity cylindrical secondary batteries 100.

[0058] In one or more embodiments, the diameter of the cylindrical secondary battery 100 is D, and 25 mm≤D≤65 mm, but is not limited thereto. For example, D can be 25 mm, 27 mm, 29 mm, 31 mm, 33 mm, 35 mm, 37 mm, 39 mm, 41 mm, 43 mm, 45 mm, 47 mm, 49 mm, 51 mm, 53 mm, 55 mm, 57 mm, 59 mm, 61 mm, 63 mm, 65 mm, or a range between any two of them. In one or more embodiments, the length of the cylindrical secondary battery 100 is L, and 40 mm≤L≤250 mm, but is not limited thereto. For example, L can be 40 mm, 50 mm, 60 mm, 70 mm, 80 mm, 90 mm, 100 mm, 110 mm, 120 mm, 130 mm, 140 mm, 150 mm, 160 mm, 170 mm, 180 mm, 190 mm, 200 mm, 210 mm, 220 mm, 230 mm, 240 mm, 250 mm, or a range between any two of them. The cylindrical secondary battery 100 has a large volume, so as to facilitate the preparation of a large-capacity cylindrical secondary battery 100, which is suitable for use in high-power or large battery packs and power-consuming devices.

[0059] FIG. 2 is a schematic diagram of a partial cross-sectional structure of a cylindrical secondary battery 100 according to an embodiment of the present application. As shown in FIG. 2, the cylindrical secondary battery 100 includes:

[0060] a housing 10, an electrode assembly 20, a first electrode terminal 30, and a current interrupt device 40. The electrode assembly 20 is disposed in the housing 10; the first electrode terminal 30 is insulatedly connected with the housing 10; the current interrupt device 40 includes a connecting plate 41, a rupture disc 42, and a first insulating member 43, the connecting plate 41 and the rupture disc 42 are arranged along an axial direction Y of the cylindrical secondary battery 100; wherein the connecting plate 41 includes a first portion 411 and a second portion 412, the first portion 411 surrounds the second portion 412, and the first portion 411 is electrically connected with the electrode assembly 20; the rupture disc 42 includes a third portion 421 and a fourth portion 422, and along the axial direction Y, a projection of the fourth portion 422 surrounds a projection of the third portion 421, the fourth portion 422 is electrically connected with the first electrode terminal 30, and the second portion 412 is electrically connected with the third portion 421; along the axial direction Y, at least a portion of the first insulating member 43 is disposed between the first portion 411 and the fourth portion 422; the first insulating member 43 has a melting point t1, and t1≥300 ℃. When the cylindrical secondary battery 100 is in a severe working condition such as external short circuit, the temperature in the housing 10 rapidly rises, and the first insulating member 43 has a high melting point and is not easy to melt in a high-temperature environment, which is conducive to the first insulating member 43 to maintain good insulation between the first portion 411 and the fourth portion 422, and reduces the risk of failure of the current interrupt device 40.

[0061] The material of the first insulating member 43 is not particularly limited in the present application, as long as the object of the present application is achieved. In one or more embodiments, the material of the first insulating member 43 comprises an oxide ceramic or a non-oxide ceramic; the oxide ceramic comprises at least one of Al2O3, ZrO, MgO, CaO, B2O3, ThO2, Cr2O3, SiO2, BeO, or 3Al2O3·2SiO2; and the non-oxide ceramic comprises at least one of a carbide ceramic, a boride ceramic, a nitride ceramic, or a silicide ceramic. The above-mentioned materials have good high-temperature resistance and are not easy to melt in a high-temperature environment, which is conducive to the first insulating member 43 to maintain good insulation between the first portion 411 and the fourth portion 422, and reduce the risk of failure of the current cutoff device 40.

[0062] The melting point of the first insulating member 43 is not particularly limited in the present application, as long as the object of the present application is achieved. In one or more embodiments, the melting point of the first insulating member 43 is t1, t1≥300℃, for example, t1may be: 300℃, 350℃, 400℃, 450℃, 500℃, 550℃, 600℃, 650℃, 700℃, 750℃, 800℃, 850℃, 900℃, 950℃, 1000℃, 1050℃, 1100℃, 1150℃, 1200℃, 1250℃, 1300℃, 1350℃, 1400℃, 1450℃, 1500℃, or a range between any two of the above values. When the cylindrical secondary battery 100 is in a harsh working condition such as external short circuit, the temperature in the housing 10 rises rapidly, and the first insulating member 43 has a high melting point and is not easy to melt in a high-temperature environment, which is conducive to the first insulating member 43 to maintain good insulation between the first portion 411 and the fourth portion 422, and reduce the risk of failure of the current cutoff device 40.

[0063] In one or more embodiments, t1≥500℃. For example, t1may be: 500℃, 550℃, 600℃, 650℃, 700℃, 750℃, 800℃, 850℃, 900℃, 950℃, 1000℃, 1050℃, 1100℃, 1150℃, 1200℃, 1250℃, 1300℃, 1350℃, 1400℃, 1450℃, 1500℃, or a range between any two of the above values. The first insulating member 43 has a higher melting point and is not easy to melt in a high-temperature environment, which is conducive to the first insulating member 43 to maintain good insulation between the first portion 411 and the fourth portion 422, and reduce the risk of failure of the current cutoff device 40.

[0064] In one or more embodiments, t1≥ 800℃. For example, t1may be: 800℃, 850℃, 900℃, 950℃, 1000℃, 1050℃, 1100℃, 1150℃, 1200℃, 1250℃, 1300℃, 1350℃, 1400℃, 1450℃, 1500℃, or a range between any two of them. The melting point of the first insulating member 43 is higher, which is not easy to melt in a high temperature environment, and is conducive to the first insulating member 43 to maintain good insulation between the first part 411 and the fourth part 422, and reduce the risk of failure of the current breaking device 40.

[0065] In one or more embodiments, t1≤ 1500℃. In the case of meeting the high temperature resistance (1500℃), the material of the first insulating member 43 is easy to select and prepare, which is conducive to the processing and production of the cylindrical secondary battery 100.

[0066] FIG. 3 is an enlarged view of A in FIG. 2, FIG. 4 is a structural schematic diagram of the first insulating member 43 of the cylindrical secondary battery 100 according to an embodiment of the present application, and FIG. 5 is a sectional structural schematic diagram of the first insulating member 43 of the cylindrical secondary battery 100 according to an embodiment of the present application. As shown in FIGS. 3, 4 and 5, the structure of the first insulating member 43 is not particularly limited in the present application, as long as the purpose of the present application is achieved. In one or more embodiments, along the axial direction Y, the first insulating member 43 includes a fifth part 431, which is arranged between the first part 411 of the connecting plate 41 and the fourth part 422 of the rupture disc 42; along the axial direction Y, the thickness of the fifth part 431 is H1, and the thickness of the second part 412 is H2, and 1.5≤ H1 / H2≤ 5. By using the above-mentioned range of the ratio of H1 and H2, after the rupture disc 42 is turned over, if the second part 412 generates free separated residues during the fracture process of the first part 411, the residues fall between the first part 411 and the fourth part 422, and since the thickness of the fifth part 431 of the first insulating member 43 is greater than the thickness of the second part 412, the thickness of the residues is less than the distance between the first part 411 and the fourth part 422, and the residues are not easy to be electrically connected to the first part 411 and the fourth part 422 at the same time, so that the rupture disc 42 and the connecting plate 41 are connected again; if the value of H1 / H2 is too large, it is easy to increase the length of the cylindrical secondary battery 100, and the energy density is lost.

[0067] In one or more embodiments, 0.3mm≤ H1≤ 0.7mm. The range of the value of H1 is conducive to good insulation of the first part 411 and the fourth part 422.

[0068] In one or more embodiments, 0.3mm≤H1≤0.7mm, for example, H1 can be: 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 or a range between any two of the above values. On the one hand, the range of H1 is conducive to good insulation of the first portion 411 and the fourth portion 422, and on the other hand, the thickness is relatively thin, which is conducive to reducing the distance between the first portion 411 and the fourth portion 422, thereby reducing the length of the cylindrical secondary battery 100 and improving the volumetric energy density of the cylindrical secondary battery 100.

[0069] In one or more embodiments, 1.5≤H1 / H2≤5, for example, H1 / H2 can be: 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, 3, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, 5 or a range between any two of the above values. In the embodiments of the present scheme, the ratio of H1 and H2 is used, and the ratio of the thickness of the fifth portion 431 and the thickness of the second portion 412 is 1.5≤H4 / H2≤5. After the rupture disc 42 is flipped, if the second portion 412 generates a free and separated residue during the rupture process, the residue falls between the first portion 411 and the fourth portion 422. Since the thickness of the first insulating piece 43 is greater than the thickness of the second portion 412, the thickness of the residue is less than the distance between the first portion 411 and the fourth portion 422, and the residue is not easy to be electrically connected to the first portion 411 and the fourth portion 422 at the same time, so that the rupture disc 42 and the connecting plate 41 are connected again. If H1 / H2 is too large, the length of the cylindrical secondary battery 100 is increased, and the energy density is lost.

[0070] The structure of the shell 10 is not particularly limited in the present application, as long as the application purpose of the present application is achieved. FIG. 6 is a structural schematic diagram I of the top wall 11 of the cylindrical secondary battery 100 according to an embodiment of the present application, FIG. 7 is a structural schematic diagram II of the top wall 11 of the cylindrical secondary battery 100 according to an embodiment of the present application, and FIG. 8 is a sectional structural schematic diagram of the top wall 11 of the cylindrical secondary battery 100 according to an embodiment of the present application. In combination with FIGS. 3, 6-8, in one or more embodiments, the shell 10 includes the top wall 11, and the top wall 11 has the through hole 110. As shown in FIGS. 3, 4 and 5, the first insulating member 43 includes the sixth portion 432, and the sixth portion 432 surrounds the fifth portion 431. At least part of the sixth portion 432 is arranged in the through hole 110, which is conducive to limiting the fifth portion 431 in the radial direction X of the cylindrical secondary battery 100 by the sixth portion 432, and is conducive to reducing the risk of the fifth portion 431 loosening between the first portion 411 and the fourth portion 422.

[0071] In one or more embodiments, as shown in FIG. 3, the shell 10 includes the side wall 12, and the side wall 12 is connected with the top wall 11.

[0072] The sealing structure of the cylindrical secondary battery 100 is not particularly limited in the present application, as long as the application purpose of the present application is achieved. In one or more embodiments, as shown in FIG. 3, the cylindrical secondary battery 100 further includes the sealing member 50. As shown in FIG. 6, the top wall 11 includes the main body portion 111 and the first extension portion 112, and the main body portion 111 surrounds the first extension portion 112. The first extension portion 112 extends from the hole wall of the through hole 110 in the radial direction X of the cylindrical secondary battery 100. Part of the first electrode terminal 30 is arranged on the side of the first extension portion 112 away from the electrode assembly 20. In the axial direction Y, the sealing member 50 is arranged between the part of the first electrode terminal 30 and the first extension portion 112, which is conducive to improving the sealing performance between the first electrode terminal 30 and the top wall 11.

[0073] In one or more embodiments, the thickness of the main body portion 111 is H3, and 1 mm≤H3≤4 mm. For example, H3 can be 1 mm, 1.2 mm, 1.4 mm, 1.6 mm, 1.8 mm, 2 mm, 2.2 mm, 2.4 mm, 2.6 mm, 2.8 mm, 3 mm, 3.2 mm, 3.4 mm, 3.6 mm, 3.8 mm, 4 mm, or a range between any two of the above values. The use of the above thickness range of H3 is conducive to the top wall 11 having greater impact resistance, so as to facilitate the electrode assembly 20 to be maintained in the shell 10 in a bumpy environment.

[0074] In one or more embodiments, the first extension 112 has a thickness H4, 0.1mm≤H4≤2mm, for example, H4 can be: 0.1mm, 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1.0mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, 1.6mm, 1.7mm, 1.8mm, 1.9mm, 2.0mm, or a range between any two of the foregoing values. The first extension 112 provides a good support to the first electrode terminal 30.

[0075] In one or more embodiments, 0.1≤H4 / H3≤0.5, for example, H4 / H3 can be: 0.1, 0.12, 0.14, 0.16, 0.18, 0.2, 0.22, 0.24, 0.26, 0.28, 0.3, 0.32, 0.34, 0.36, 0.38, 0.4, 0.42, 0.44, 0.46, 0.48, 0.5, or a range between any two of the foregoing values. With the above ratio range of H4 and H3, the thickness of the first extension 112 is reduced, thereby reducing the length of the cylindrical secondary battery 100, and the volumetric energy density of the cylindrical secondary battery 100 is improved, while the first extension 112 provides a good support to the first electrode terminal 30.

[0076] In one or more embodiments, the material of the sealing member 50 includes fluororubber, which has good corrosion resistance and high temperature resistance, thereby improving the sealing effect of the cylindrical secondary battery 100 and reducing the probability of electrolyte leakage.

[0077] In one or more embodiments, the sealing member 50 has a thickness H5, 0.5mm≤H5≤2.3mm, for example, H5 can be: 0.5mm, 0.55mm, 0.6mm, 0.65mm, 0.7mm, 0.75mm, 0.8mm, 0.85mm, 0.9mm, 0.95mm, 1.0mm, 1.05mm, 1.1mm, 1.15mm, 1.2mm, 1.25mm, 1.3mm, 1.35mm, 1.4mm, 1.45mm, 1.5mm, 1.55mm, 1.6mm, 1.65mm, 1.7mm, 1.75mm, 1.8mm, 1.85mm, 1.9mm, 1.95mm, 2.0mm, 2.15mm, 2.2mm, 2.25mm, 2.3mm, or a range between any two of the foregoing values. With the above thickness range of H5, the sealing member 50 provides a good sealing effect, and the thickness is relatively thin, thereby reducing the length of the cylindrical secondary battery 100, and the volumetric energy density of the cylindrical secondary battery 100 is improved.

[0078] The structure of the insulation connection between the first electrode terminal 30 and the case 10 is not particularly limited as long as the object of the application is achieved. FIG. 9 is a structural schematic diagram of the second insulation piece 60 of the cylindrical secondary battery 100 according to an embodiment of the application, and FIG. 10 is a sectional structural schematic diagram of the second insulation piece 60 of the cylindrical secondary battery 100 according to an embodiment of the application. In combination with FIGS. 3, 8, 9, and 10, in one or more embodiments, the cylindrical secondary battery 100 comprises the second insulation piece 60, the top wall 11 comprises the second extension 113, the main body part 111 and the second extension 113 are arranged along the axial direction Y of the cylindrical secondary battery 100, the second extension 113 comprises a seventh part 1131 and an eighth part 1132, the seventh part 1131 extends from the main body part 111 along the axial direction Y of the cylindrical secondary battery 100, and the eighth part 1132 extends from the seventh part 1131 along the opposite direction of the radial direction X of the cylindrical secondary battery 100; the second insulation piece 60 comprises a ninth part 61, the ninth part 61 extends along the axial direction Y of the cylindrical secondary battery 100, and along the radial direction X of the cylindrical secondary battery 100, the ninth part 61 is arranged between the seventh part 1131 and the first electrode terminal 30 to insulate and connect the seventh part 1131 and the first electrode terminal 30.

[0079] In one or more embodiments, the ninth part 61 is annular, and in the case of insulating and connecting the first electrode terminal 30 and the case 10, the first electrode terminal 30 is limited along the radial direction X of the cylindrical secondary battery 100, thereby improving the position stability of the first electrode terminal 30.

[0080] In one or more embodiments, the second insulation piece 60 comprises a tenth part 62, the tenth part 62 extends from the ninth part 61 along the opposite direction of the radial direction X of the cylindrical secondary battery 100, and along the axial direction Y of the cylindrical secondary battery 100, the tenth part 62 is arranged between the eighth part 1132 and the first electrode terminal 30 to insulate and connect the eighth part 1132 and the first electrode terminal 30.

[0081] In one or more embodiments, the tenth part 62 is annular, and in the case of insulating and connecting the first electrode terminal 30 and the case 10, the first electrode terminal 30 is limited along the axial direction Y of the cylindrical secondary battery 100, thereby improving the position stability of the first electrode terminal 30.

[0082] In one or more embodiments, the material and melting point of the second insulation piece 60 are the same as the material and melting point of the first insulation piece 43.

[0083] As shown in FIG. 3, in one or more embodiments, the rupture disc 42 is configured to flip over relative to the connecting plate 41 when the gas pressure inside the shell 10 reaches the first threshold value (when the cylindrical secondary battery 100 fails, the gas pressure inside the shell 10 rises, and when the gas pressure inside the shell 10 reaches the first threshold value, the rupture disc 42 is flipped over by the gas pressure inside the shell 10), the rupture disc 42 drives a part of the second portion 412 to separate from the first portion 411, and the rupture disc 42 is disconnected from the connecting plate 41 to disconnect the first electrode terminal 30 from the electrode assembly 20.

[0084] In one or more embodiments, the first threshold value is P1, and 1.0 MPa≤P1≤1.6 MPa, for example, P1may be: 1.0 MPa, 1.02 MPa, 1.04 MPa, 1.06 MPa, 1.08 MPa, 1.1 MPa, 1.12 MPa, 1.14 MPa, 1.16 MPa, 1.18 MPa, 1.2 MPa, 1.22 MPa, 1.24 MPa, 1.26 MPa, 1.28 MPa, 1.3 MPa, 1.32 MPa, 1.34 MPa, 1.36 MPa, 1.38 MPa, 1.4 MPa, 1.42 MPa, 1.44 MPa, 1.46 MPa, 1.48 MPa, 1.5 MPa, 1.52 MPa, 1.54 MPa, 1.56 MPa, 1.58 MPa, 1.6 MPa, or a range between any two of the above values. When the gas pressure inside the shell 10 of the cylindrical secondary battery 100 rises to the range of P1, the current interrupt device 40 is disconnected to disconnect the electrode assembly 20 and the first electrode terminal 30, thereby forming an open circuit to the outside and improving the safety of the cylindrical secondary battery 100.

[0085] The structure of the connecting plate 41 is not particularly limited in the present application as long as the purpose of the present application is achieved. FIG. 11 is a schematic diagram of the structure of the connecting plate 41 of the cylindrical secondary battery 100 according to an embodiment of the present application, and FIG. 12 is a schematic diagram of the cross-sectional structure of the connecting plate 41 of the cylindrical secondary battery 100 according to an embodiment of the present application. Please refer to FIGS. 3, 11, and 12, in one or more embodiments, a part of the second portion 412 and the third portion 421 are welded to form a welded surface 4121, the second portion 412 of the connecting plate 41 includes a first annular groove 4122, and the projection of the first annular groove 4122 surrounds the projection of the welded surface 4121 along the axial direction Y of the cylindrical secondary battery 100. The thickness of the groove bottom of the first annular groove 4122 is relatively thin, so that after the second portion 412 is flipped over by the rupture disc 42, the second portion 412 is broken in the first annular groove 4122 to quickly disconnect the electrical connection between the first portion 411 and the second portion 412.

[0086] In one or more embodiments, the first portion 411 is provided with a vent hole 4111. When the cylindrical secondary battery 100 is externally short-circuited or in a high-temperature environment, high-pressure gas in the casing 10 passes through the vent hole 4111 to exert pressure on the rupture disc 42, causing the rupture disc 42 to quickly flip relative to the connecting plate 41. In one or more embodiments, the vent hole 4111 is at least two and is arranged around the axis L0.

[0087] The structure of the rupture disc 42 is not particularly limited in the present application, as long as the purpose of the present application is achieved. FIG. 13 is a schematic diagram of the structure of the rupture disc 42 of the cylindrical secondary battery 100 according to an embodiment of the present application, and FIG. 14 is a schematic diagram of the cross-sectional structure of the rupture disc 42 of the cylindrical secondary battery 100 according to an embodiment of the present application. Please refer to FIGS. 3, 13 and 14. In one or more embodiments, the fourth portion 422 of the rupture disc 42 includes a second annular groove 4223. In the axial direction Y of the cylindrical secondary battery, the projection of the second annular groove 4223 surrounds the projection of the third portion 421. The portion of the fourth portion 422 inside the second annular groove 4223 and the third portion 421 form a flip body 423.

[0088] The flip body 423 flips relative to the connecting plate 41 when the gas pressure in the casing 10 reaches a first threshold value. The rupture disc 42 is configured to break the second annular groove 4223 to form an exhaust port when the gas pressure in the casing 10 reaches a second threshold value, so that the gas in the casing 10 is discharged to the outside of the casing 10 through the exhaust port.

[0089] In one or more embodiments, the second annular groove 4223 is a non-closed ring, so that after the second annular groove 4223 breaks, the flip body 423 is not easily separated from the fourth portion 422, reducing the splashing of debris to the external environment when the cylindrical secondary battery 100 is depressurized.

[0090] In one or more embodiments, the second threshold value is P2, 1.9 MPa≤P2≤2.5 MPa, for example, P2may be: 1.90 MPa, 1.92 MPa, 1.94 MPa, 1.96 MPa, 1.98 MPa, 2.00 MPa, 2.02 MPa, 2.04 MPa, 2.06 MPa, 2.08 MPa, 2.10 MPa, 2.12 MPa, 2.14 MPa, 2.16 MPa, 2.18 MPa, 2.20 MPa, 2.22 MPa, 2.24 MPa, 2.26 MPa, 2.28 MPa, 2.30 MPa, 2.32 MPa, 2.34 MPa, 2.36 MPa, 2.38 MPa, 2.40 MPa, 2.42 MPa, 2.44 MPa, 2.46 MPa, 2.48 MPa, 2.50 MPa, or a range between any two of the above values. When the cylindrical secondary battery 100 is caused by external short circuit or high temperature environment, the pressure in the shell 10 rises to the range of P2, the second annular groove 4223 of the explosion-proof sheet 42 is broken to form an exhaust port, so as to facilitate the external exhaust of the high-pressure gas in the shell 10, reduce the probability of explosion or fire of the cylindrical secondary battery 100, and improve the safety of the secondary battery.

[0091] In one or more embodiments, as shown in FIG. 3, the fourth portion 422 includes a first section 4221 extending along the radial direction X of the cylindrical secondary battery 100, the first section 4221 is connected with the first electrode terminal 30, and at least part of the sealing member 50 is arranged between the first section 4221 and the first extension 112 along the axial direction Y; the first section 4221 extends along the radial direction X of the cylindrical secondary battery 100 and is connected with the first electrode terminal 30, and at least part of the sealing member 50 is arranged between the first section 4221 and the first extension 112, which is conducive to forming a good seal between the fourth portion 422 of the explosion-proof sheet 42 and the first extension 112 of the top wall 11.

[0092] In one or more embodiments, the fourth portion 422 includes a second section 4222 extending along the axial direction Y and connected to the first section 4221 extending along the radial direction X of the cylindrical secondary battery 100, and a portion of the sixth portion 432 of the first insulating member 43 is arranged between the second section 4222 and the first extension 112. The sixth portion 432 of the first insulating member 43 has a high melting point, and is less likely to melt in a high-temperature environment, which is conducive to maintaining good insulation between the second section 4222 of the rupture disc 42 and the first extension 112 of the top wall 11, and reducing the risk of failure of the current interrupt device 40. The first section 4221 extends along the radial direction X, and the second section 4222 extends along the axial direction Y of the cylindrical secondary battery 100 and is connected to the first electrode terminal 30, which is conducive to forming a stable electrical connection structure of the fourth portion 422 of the rupture disc in two directions (the axial direction Y and the radial direction X of the cylindrical secondary battery) of the first electrode terminal 30.

[0093] In one or more embodiments, the sixth portion 432 of the first insulating member 43 extends beyond the first extension 112 along the axial direction Y. In a high-temperature environment, the sealing member 50 is likely to melt, and the sixth portion 432 of the first insulating member 43 has a high melting point and is less likely to melt, which is conducive to forming a support between the first extension 112 of the housing 10 and the first section 4221 of the rupture disc 42, spacing the first extension 112 and the first section 4221, maintaining good insulation between the first extension 112 and the first section 4221 of the rupture disc 42, and reducing the risk of failure of the current interrupt device 40.

[0094] In the above embodiments, the cylindrical secondary battery 100 is a full-tab battery, and the electrode assembly 20 has different polarities at the two ends along the axial direction Y. In one or more embodiments, the end of the electrode assembly 20 facing the top wall 11 is a positive electrode, and the end of the electrode assembly 20 facing away from the top wall 11 is a negative electrode. A negative current collector plate is welded between the bottom wall of the housing 10 and the negative electrode of the electrode assembly 20, and the negative current collector plate electrically connects the bottom wall of the housing 10 and the negative electrode of the electrode assembly 20. In one or more embodiments, the end of the electrode assembly 20 facing the top wall 11 is a negative electrode, and the end of the electrode assembly 20 facing away from the top wall 11 is a positive electrode. A positive current collector plate is welded between the bottom wall of the housing 10 and the positive electrode of the electrode assembly 20, and the positive current collector plate electrically connects the bottom wall of the housing 10 and the positive electrode of the electrode assembly 20.

[0095] In a second aspect, the application provides a battery pack 200. FIG. 15 is a structural schematic diagram of the battery pack 200 according to an embodiment of the application. As shown in FIG. 15, the battery pack 200 includes the cylindrical secondary battery 100 of any of the above embodiments. The cylindrical secondary battery 100 is at least one. In one or more embodiments, the cylindrical secondary battery 100 is a plurality of cylindrical secondary batteries 100 connected in series or in parallel, or a combination of series and parallel connection.

[0096] In a third aspect, the application provides a power consuming device 300 comprising the cylindrical secondary battery 100 or the battery pack 200 of any of the above embodiments.

[0097] In one or more embodiments, FIG. 16 is a structural schematic diagram of a first power consuming device according to an embodiment of the application. As shown in FIG. 16, the power consuming device 300 comprises the battery pack 200 of the above embodiments, and the battery pack 200 comprises the cylindrical secondary battery 100 of the above embodiments.

[0098] In one or more embodiments, FIG. 17 is a structural schematic diagram of a second power consuming device according to an embodiment of the application. As shown in FIG. 17, the power consuming device 300 comprises the cylindrical secondary battery 100 of the above embodiments.

[0099] The power consuming device is not particularly limited in the application, and the power consuming device includes the power consuming device known in the prior art. For example, the power consuming device includes, but is not limited to, a computer, a smart phone, a backup power supply, a two-wheeled vehicle, a drone, a power tool, or an energy storage device, etc.

[0100] The above description is merely preferred embodiments of the present application, and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the scope of protection of the present application.

Claims

1. A cylindrical secondary battery characterized by comprising: Comprising: a housing; an electrode assembly disposed in the housing; a first electrode terminal insulatedly connected with the housing; a current interrupting device comprising a connecting plate, a rupture disc and a first insulating member, the connecting plate and the rupture disc are arranged along an axial direction of the cylindrical secondary battery; wherein, the connecting plate comprises a first portion and a second portion, the first portion surrounds the second portion, the first portion is electrically connected with the electrode assembly; the rupture disc comprises a third portion and a fourth portion, along the axial direction, a projection of the fourth portion surrounds a projection of the third portion, the fourth portion is electrically connected with the first electrode terminal, the second portion and the third portion are electrically connected; along the axial direction, at least a portion of the first insulating member is disposed between the first portion and the fourth portion; a melting point of the first insulating member is t1, t1≥300℃.

2. The cylindrical secondary battery according to claim 1, characterized by t1≥500℃。 3. The cylindrical secondary battery according to claim 2, characterized by t1≥800℃。 4. The cylindrical secondary battery according to any one of claims 1 to 3, characterized by, t1≤1500℃。 5. The cylindrical secondary battery according to any one of claims 1 to 4, wherein, a material of the first insulating member comprises an oxide ceramic or a non-oxide ceramic; the oxide ceramic comprises at least one of Al2O3, ZrO, MgO, CaO, B2O3, ThO2, Cr2O3, SiO2, BeO or 3Al2O3·2SiO2; the non-oxide ceramic comprises at least one of a carbide ceramic, a boride ceramic, a nitride ceramic or a silicide ceramic.

6. The cylindrical secondary battery according to any one of claims 1 to 5, wherein, the first insulating member comprises a fifth portion, along the axial direction, the fifth portion is disposed between the first portion and the fourth portion; along the axial direction, a thickness of the fifth portion is H1, a thickness of the second portion is H2, 1.5≤H1 / H2≤5.

7. The cylindrical secondary battery according to claim 6, characterized by 0.3mm≤H1≤0.7mm.

8. The cylindrical secondary battery according to claim 6 or 7, wherein, the housing comprises a top wall, the top wall has a through hole; the first insulating member comprises a sixth portion, the sixth portion surrounds the fifth portion, at least a portion of the sixth portion is disposed in the through hole.

9. The cylindrical secondary battery according to claim 8, characterized by Further comprising: a sealing member; the cylindrical secondary battery is a cylindrical secondary battery, the top wall comprises a first extension, the first extension extends from a hole wall of the through hole along a radial direction of the cylindrical secondary battery; a portion of the first electrode terminal is disposed on a side of the first extension away from the electrode assembly; along the axial direction, the sealing member is disposed between the portion of the first electrode terminal and the first extension.

10. The cylindrical secondary battery according to claim 9, wherein, the fourth portion comprises a first segment; the first segment extends along a radial direction of the cylindrical secondary battery, the first segment is connected with the first electrode terminal, along the axial direction, at least a portion of the sealing member is disposed between the first segment and the first extension.

11. The cylindrical secondary battery according to claim 10, wherein, the fourth portion comprises a second segment, the second segment extends along the axial direction and is connected with the first segment; The sixth portion is disposed between the second section and the first extension portion in the radial direction of the cylindrical secondary battery.

12. The cylindrical secondary battery according to claim 11, wherein The sixth portion exceeds the first extension portion in the axial direction.

13. The cylindrical secondary battery according to any one of claims 9 to 12, wherein The top wall includes a main body portion that surrounds the first extension portion, the main body portion has a thickness H3, the first extension portion has a thickness H4, and 0.1 ≤ H4 / H3 ≤ 0.

5.

14. The cylindrical secondary battery according to claim 13, characterized by 1 mm ≤ H3 ≤ 4 mm.

15. The cylindrical secondary battery according to any one of claims 9 to 14, wherein The material of the seal includes fluoro rubber.

16. The cylindrical secondary battery according to any one of claims 9 to 15, characterized by, The seal has a thickness H5, and 0.5 mm ≤ H5 ≤ 2.3 mm.

17. The cylindrical secondary battery according to any one of claims 1 to 16, characterized by, Further comprising: a second insulating member; the cylindrical secondary battery is a cylindrical secondary battery; the top wall includes a second extension portion, the main body portion and the second extension portion are arranged in the axial direction of the cylindrical secondary battery, the second extension portion includes a seventh portion, the seventh portion is extended from the main body portion in the axial direction of the cylindrical secondary battery; the second insulating member includes a ninth portion, the ninth portion is extended in the axial direction of the cylindrical secondary battery, and the ninth portion is disposed between the seventh portion and the first electrode terminal in the radial direction of the cylindrical secondary battery to insulate and connect the seventh portion and the first electrode terminal.

18. The cylindrical secondary battery according to claim 17, wherein the second extension portion further includes an eighth portion, the eighth portion is extended from the seventh portion in the opposite direction of the radial direction of the cylindrical secondary battery; the second insulating member further includes a tenth portion, the tenth portion is extended from the ninth portion in the opposite direction of the radial direction of the cylindrical secondary battery, and the tenth portion is disposed between the eighth portion and the first electrode terminal in the axial direction of the cylindrical secondary battery to insulate and connect the eighth portion and the first electrode terminal.

19. The cylindrical secondary battery according to any one of claims 1 to 18, wherein the cylindrical secondary battery is a cylindrical secondary battery; the cylindrical secondary battery has a diameter D, and 25 mm ≤ D ≤ 65 mm; and / or the cylindrical secondary battery has a length L, and 40 mm ≤ L ≤ 250 mm.

20. A battery pack, characterized by The cylindrical secondary battery according to any one of claims 1 to 19.

21. An electrical device, comprising: The battery pack according to claim 20.

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