Cylindrical secondary battery, battery pack, and electrical apparatus

Abstract

A cylindrical secondary battery, a battery pack, and an electrical apparatus. The cylindrical secondary battery comprises: a casing, a first electrode terminal, and a first insulating member. The casing comprises a top wall, and the top wall is provided with a through hole. At least part of the first electrode terminal is provided in the through hole. The first insulating member insulatingly connects the top wall and the first electrode terminal. The melting point of the first insulating member is t1, where t1≥300°C. The first insulating member has a high melting point and can withstand a higher temperature. The first insulating member does not easily melt at high temperatures, which helps the first insulating member to maintain good insulation between the top wall and the first electrode terminal, and reduces the risk of an internal short circuit of the cylindrical secondary battery caused by an electrical connection between the top wall and the first electrode terminal.

Description

Cylindrical secondary battery, battery pack and electric device

[0001] This application claims priority to the Chinese patent application No. 202410895954.7, 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, and in particular, to a cylindrical secondary battery, a battery pack and an electric device. BACKGROUND

[0003] Secondary batteries such as lithium ion batteries have high energy density, long service life and other characteristics, and are widely used. With the continuous enrichment of application scenarios of secondary batteries, in some application scenarios, the capacity of the secondary battery is larger, so as to provide high power and long endurance for users.

[0004] However, with the increase of the capacity of the secondary battery, under abnormal working conditions, the secondary battery will release more heat, which increases the risk of uncontrolled short circuit in the secondary battery, and reduces the use safety 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 use safety of the secondary battery.

[0006] In a first aspect, the present application provides a cylindrical secondary battery, comprising: a shell comprising a top wall, the top wall having a through hole; a first electrode terminal, at least a part of the first electrode terminal being arranged in the through hole; a first insulating piece, insulatingly connecting the top wall and the first electrode terminal; the melting point of the first insulating piece is t1, t1≥300℃. The melting point of the first insulating piece is higher, which can withstand higher temperature, and the first insulating piece is not easy to melt, which is conducive to maintaining good insulation between the top wall and the first electrode terminal, and reducing the risk of electrical connection between the top wall and the first electrode terminal leading to internal short circuit of the cylindrical secondary battery.

[0007] In one or more embodiments, t1≥500℃. The melting point of the first insulating piece is higher, which can withstand higher temperature, and the first insulating piece is not easy to melt, which is conducive to maintaining good insulation between the top wall and the first electrode terminal, and further reducing the risk of electrical connection between the top wall and the first electrode terminal leading to internal short circuit of the cylindrical secondary battery.

[0008] In one or more embodiments, t1 is greater than or equal to 800°C. The first insulating member has a higher melting point and can withstand higher temperatures, and the first insulating member is less likely to melt, which is conducive to maintaining good insulation between the top wall and the first electrode terminal and further reduces the risk of electrical connection between the top wall and the first electrode terminal causing internal short circuit of the cylindrical secondary battery.

[0009] In one or more embodiments, t1 is less than or equal to 1500°C. The first insulating member is easier to select and prepare under conditions that meet most high-temperature environments, which facilitates processing and production.

[0010] In one or more embodiments, the material of the first insulating member 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 less likely to melt in a high-temperature environment, which is conducive to maintaining good insulation between the top wall and the first electrode terminal and reducing the risk of electrical connection between the top wall and the first electrode terminal causing internal short circuit of the cylindrical secondary battery.

[0011] In one or more embodiments, the electrode assembly and the top wall are arranged along an axial direction of the cylindrical secondary battery; the top wall includes a main body portion and a first extension portion, the first extension portion includes a first portion and a second portion, the first portion extends from the main body portion along the axial direction of the cylindrical secondary battery, and the second portion extends from the first portion in a direction opposite to a radial direction of the cylindrical secondary battery; and the first insulating member includes a third portion, the third portion extends along the axial direction of the cylindrical secondary battery, and at least part of the third portion is arranged between the first portion and the first electrode terminal along the radial direction of the cylindrical secondary battery, so that the first portion and the first electrode terminal are insulated and connected, the first insulating member has a higher melting point, and the third portion is less likely to melt in a high-temperature environment, which is conducive to maintaining good insulation between the top wall and the first electrode terminal along the radial direction of the cylindrical secondary battery and reducing the risk of electrical connection between the top wall and the first electrode terminal causing internal short circuit of the cylindrical secondary battery.

[0012] In one or more embodiments, the first insulating member includes a fourth portion, the fourth portion extends from the third portion in a direction opposite to the radial direction of the cylindrical secondary battery, and the fourth portion insulates and connects the second portion and the first electrode terminal, the first insulating member has a higher melting point, and the fourth portion is less likely to melt in a high-temperature environment, which is conducive to maintaining good insulation between the top wall and the first electrode terminal along the axial direction of the cylindrical secondary battery and reducing the risk of electrical connection between the top wall and the first electrode terminal causing internal short circuit of the cylindrical secondary battery.

[0013] In one or more embodiments, the third portion has a thickness H1 along the radial direction of the cylindrical secondary battery, and 0.5mm≤H1≤1.5mm. The thickness range of H1 is beneficial to improve the insulation performance of the third portion, and the third portion is beneficial to form a support between the first portion and the first electrode terminal along the radial direction of the cylindrical secondary battery, thereby improving the position stability of the first electrode terminal along the radial direction of the cylindrical secondary battery.

[0014] In one or more embodiments, the fourth portion has a thickness H2 along the axial direction of the cylindrical secondary battery, and 0.5mm≤H2≤1.5mm. The thickness range of H2 is beneficial to improve the insulation performance of the fourth portion, and the fourth portion is beneficial to form a support between the second portion and the first electrode terminal along the axial direction of the cylindrical secondary battery, thereby improving the position stability of the first electrode terminal along the axial direction of the cylindrical secondary battery.

[0015] In one or more embodiments, the projection of the second portion and the projection of the fourth portion have an overlapping portion along the axial direction of the cylindrical secondary battery, and the projection of the fourth portion and the projection of the first electrode terminal have an overlapping portion, so as to form axial limiting for the first electrode terminal.

[0016] In one or more embodiments, the projection of the second portion and the projection of the first electrode terminal have an overlapping portion along the axial direction of the cylindrical secondary battery, which is beneficial to further enhance the limiting of the first electrode terminal in the axial direction.

[0017] In one or more embodiments, the first electrode terminal comprises a fifth portion, at least two sixth portions and a seventh portion; the fifth portion extends along the radial direction of the cylindrical secondary battery, the sixth portion extends from the fifth portion away from the electrode assembly, and the opening is formed between the adjacent two sixth portions; the seventh portion connects the sixth portions and forms the end part of the first electrode terminal for external electrical connection; the cylindrical secondary battery further comprises a second insulating member, the second insulating member comprises an inner annular wall, the inner annular wall is arranged between the sixth portion of the first electrode terminal and the second portion of the first extension part and extends along the axial direction of the cylindrical secondary battery, so as to form insulation isolation between the sixth portion and the second portion, thereby reducing the probability of short circuit of the cylindrical secondary battery caused by electrical connection between the sixth portion of the first electrode terminal and the second portion of the first extension part.

[0018] In one or more embodiments, the second insulating member further comprises an outer annular wall and a top annular wall, the outer annular wall is arranged on the side of the first portion of the first extension part away from the axis of the cylindrical secondary battery and extends along the axial direction of the cylindrical secondary battery; the top annular wall extends along the radial direction of the cylindrical secondary battery and connects the outer annular wall and the inner annular wall; the outer annular wall and the top annular wall cover the first extension part and form insulation protection for the first extension part, which is beneficial to reduce the risk of short circuit connection between the external components (such as bus bars) and the first extension part and the first electrode terminal.

[0019] In one or more embodiments, the second insulating piece further comprises a limiting portion extended by the inner ring wall and protruding into the opening, and a projection of the limiting portion and a projection of the seventh portion of the first electrode terminal overlap in the axial direction of the cylindrical secondary battery, so that the seventh portion limits the second insulating piece in the axial direction of the cylindrical secondary battery, thereby reducing the risk of the second insulating piece being separated from the top wall.

[0020] In one or more embodiments, the sealing member is further provided, and the top wall comprises a second extending portion extended by the hole wall of the through hole in the opposite direction of the radial direction of the cylindrical secondary battery; and at least a portion of the sealing member is arranged between the second extending portion and the first electrode terminal in the axial direction of the cylindrical secondary battery, so as to form a sealed connection between the second extending portion and the first electrode terminal.

[0021] In one or more embodiments, the material of the sealing member comprises fluororubber, which 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.

[0022] In one or more embodiments, the thickness of the sealing member is H3, and 1.2≤H3 / H2≤1.5, 0.5mm≤H3≤2.3mm in the axial direction of the cylindrical secondary battery. H3 / H2 is in the above ratio range, and as the thickness of the fourth portion of the first insulating piece increases, the thickness of the sealing member is slightly greater than the thickness of the fourth portion of the first insulating piece, which is conducive to matching the thickness of the first insulating piece and improving the sealing performance of the cylindrical secondary battery. The thickness of the fluororubber in the above H3 range is conducive to providing good sealing effect, and the thickness is relatively thin, which is conducive to reducing the length of the cylindrical secondary battery, thereby improving the volume energy density of the cylindrical secondary battery.

[0023] In one or more embodiments, 0.5mm≤H2≤1.5mm. The thickness of H2 in the above range is conducive to improving the insulation performance of the fourth portion in the axial direction of the cylindrical secondary battery, and conducive to maintaining good insulation between the top wall and the first electrode terminal. On the other hand, the fourth portion is not easy to melt in a high temperature environment, and is conducive to forming a support between the second portion and the first electrode terminal in the axial direction of the cylindrical secondary battery, thereby limiting the first electrode terminal in the axial direction, which is conducive to improving the position stability of the first electrode terminal in the axial direction of the cylindrical secondary battery, and reducing the problem of insulation failure caused by axial shaking.

[0024] In one or more embodiments, the current cut-off device is further provided, and the current cut-off device is electrically connected between the electrode assembly and the first electrode terminal, and is configured to be disconnected when the air pressure in the shell reaches a first threshold, so as to disconnect the electrode assembly and the first electrode terminal, thereby disconnecting the charge-discharge circuit of the cylindrical secondary battery and providing safety protection for the cylindrical secondary battery.

[0025] In one or more embodiments, the current interrupt device includes an explosion-proof sheet connected to the first electrode terminal and a hole plate connected to the electrode assembly, the explosion-proof sheet and the hole plate are electrically connected, when the cylindrical secondary battery fails, the internal pressure of the shell increases, when the internal pressure in the shell reaches a first threshold value, the explosion-proof sheet is pushed by the internal pressure of the shell, the middle part of the explosion-proof sheet is turned over towards the seventh part of the first electrode terminal, and the electrical connection between the explosion-proof sheet and the hole plate is disconnected, so that the electrode assembly and the first electrode terminal are electrically disconnected, so as to disconnect the charge-discharge circuit of the cylindrical secondary battery and provide safety protection for the cylindrical secondary battery.

[0026] In one or more embodiments, the diameter of the cylindrical secondary battery is D, and 25mm≤D≤65mm; and / or, the length of the cylindrical secondary battery is L, and 40mm≤L≤250mm. The cylindrical secondary battery adopts the above-mentioned diameter and length range, which is easy to prepare a large-capacity cylindrical secondary battery, so as to be suitable for application scenarios with large-capacity cylindrical secondary battery usage requirements.

[0027] In a second aspect, the application provides a battery pack comprising the cylindrical secondary battery described above.

[0028] In a third aspect, the application provides a power consumption device comprising the cylindrical secondary battery or the battery pack described above.

[0029] The cylindrical secondary battery, the battery pack and the power consumption device provided by the embodiments of the application, the cylindrical secondary battery comprises: a shell, a first electrode terminal and a first insulating piece, the shell comprises a top wall, the top wall has a through hole; at least part of the first electrode terminal is arranged in the through hole; the first insulating piece insulatively connects the top wall and the first electrode terminal; the melting point of the first insulating piece is t1, and t1≥300℃. The melting point of the first insulating piece is relatively high, which can withstand higher temperature, and the first insulating piece is not easy to melt, which is conducive to maintaining good insulation between the top wall and the first electrode terminal, and reducing the risk of short circuit in the cylindrical secondary battery caused by electrical connection between the top wall and the first electrode terminal.

[0030] Of course, it is not necessary for any product implementing the present application to achieve all the advantages mentioned above. BRIEF DESCRIPTION OF DRAWINGS

[0031] The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this application, illustrate embodiments of the present application and serve to explain the present application, but do not limit the present application.

[0032] FIG. 1 is a structural schematic diagram of a cylindrical secondary battery according to an embodiment of the present application;

[0033] FIG. 2 is a partial cross-sectional structural schematic diagram of a cylindrical secondary battery according to an embodiment of the present application;

[0034] FIG. 3 is an enlarged view of A in FIG. 2;

[0035] FIG. 4 is a structural schematic view of a top wall of a cylindrical secondary battery according to an embodiment of the present application;

[0036] FIG. 5 is a structural schematic view of a top wall of a cylindrical secondary battery according to an embodiment of the present application;

[0037] FIG. 6 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. 7 is a structural schematic view of a first insulating member of a cylindrical secondary battery according to an embodiment of the present application;

[0039] FIG. 8 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;

[0040] FIG. 9 is a structural schematic view of a first electrode terminal of a cylindrical secondary battery according to an embodiment of the present application;

[0041] FIG. 10 is a cross-sectional structural schematic view of a first electrode terminal of a cylindrical secondary battery according to an embodiment of the present application;

[0042] FIG. 11 is a structural schematic view of a second insulating member of a cylindrical secondary battery according to an embodiment of the present application;

[0043] FIG. 12 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;

[0044] FIG. 13 is a structural schematic view of a battery pack according to an embodiment of the present application;

[0045] FIG. 14 is a structural schematic view of a first power consuming device according to an embodiment of the present application;

[0046] FIG. 15 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 101, through hole 111, main body part 11, first extension part 12, first part 121, second part 122, second extension part 13, first electrode terminal 20, fifth part 21, sixth part 22, seventh part 23, opening 24, first insulating part 30, third part 31, fourth part 32, electrode assembly 40, sealing part 50, second insulating part 60, inner ring wall 61, outer ring wall 62, top ring wall 63, limiting part 64, current interrupting device 70, anti-explosion sheet 71, tenth part 711, eleventh part 712, aperture plate 72, eighth part 721, ninth part 722, third insulating part 73; 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 otherwise explicitly specified and limited, the terms “mounting”, “connection”, “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 explicitly specified and limited.

[0051] In this document, the reference to “embodiments” means that the specific features, structures or properties described in connection 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 all refer to the same embodiment, nor is it necessarily mutually exclusive or alternative embodiments. In the case of no conflict, the various embodiments in the present application can be combined with each other.

[0052] The embodiments of the present application mainly improve the first insulating piece connecting the top wall of the cylindrical secondary battery and the first electrode terminal, so as to reduce the probability of internal short circuit of the cylindrical secondary battery in a high temperature environment and improve the use safety of the secondary battery.

[0053] In order to better understand the present application, the cylindrical secondary battery of the embodiments of the present application is described in detail below.

[0054] It should be noted that the sizes of various components in the embodiments of the present application and the sizes of the cylindrical secondary battery shown in the drawings are only exemplary and should not constitute any limitation on the present application.

[0055] FIG. 1 is a structural schematic 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 a plane perpendicular to the axis L0 and points 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 battery is D.

[0056] In one or more embodiments, the diameter of the cylindrical secondary battery 100 is D, and 25mm≤D≤65mm. For example, D can be 25mm, 27mm, 29mm, 31mm, 33mm, 35mm, 37mm, 39mm, 41mm, 43mm, 45mm, 47mm, 49mm, 51mm, 53mm, 55mm, 57mm, 59mm, 61mm, 63mm, 65mm, or a range between any two of them.

[0057] In one or more embodiments, the length of the cylindrical secondary battery 100 is L, and 40mm≤L≤250mm. For example, L can be 40mm, 50mm, 60mm, 70mm, 80mm, 90mm, 100mm, 110mm, 120mm, 130mm, 140mm, 150mm, 160mm, 170mm, 180mm, 190mm, 200mm, 210mm, 220mm, 230mm, 240mm, 250mm, or a range between any two of them.

[0058] 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 suitable for application scenarios requiring the use of large-capacity cylindrical secondary batteries 100.

[0059] FIG. 2 is a schematic diagram of a partial cross-sectional structure of a cylindrical secondary battery according to an embodiment of the present application. As shown in FIG. 2, the cylindrical secondary battery 100 includes a case 10, a first electrode terminal 20, and a first insulating member 30. The case 10 includes a top wall 101 having a through hole 111 in which at least a portion of the first electrode terminal 20 is disposed, and the first insulating member 30 insulatingly connects the top wall 101 and the first electrode terminal 20. The first insulating member 30 has a melting point t1, and t1≥300°C. The first insulating member 30 has a high melting point and can withstand a high temperature. The first insulating member 30 is less likely to melt, which is conducive to maintaining good insulation between the top wall 101 and the first electrode terminal 20, reducing the risk of electrical connection between the top wall 101 and the first electrode terminal 20 causing internal short circuit of the cylindrical secondary battery 100, and reducing the risk of failure of a safety device (e.g., a current interrupt device 70) of the cylindrical secondary battery 100.

[0060] The material of the first insulating member 30 is not particularly limited in the present application, as long as the purpose of the present application is achieved. In one or more embodiments, the material of the first insulating member 30 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 less likely to melt in a high-temperature environment, which is conducive to maintaining good insulation between the top wall 101 and the first electrode terminal 20, reducing the risk of electrical connection between the top wall 101 and the first electrode terminal 20 causing internal short circuit of the cylindrical secondary battery 100.

[0061] The melting point of the first insulating member 30 is not particularly limited in the present application, as long as the purpose of the present application is achieved. In one or more embodiments, the first insulating member 30 has a melting point t1, and t1≥300°C, for example, t1may be 300°C, 350°C, 400°C, 450°C, 500°C, 550°C, 600°C, 650°C, 700°C, 750°C, 800°C, 850°C, 900°C, 950°C, 1000°C, 1050°C, 1100°C, 1150°C, 1200°C, 1250°C, 1300°C, 1350°C, 1400°C, 1450°C, 1500°C, or a range between any two of the above values. The first insulating member 30 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 top wall 101 and the first electrode terminal 20 and further reducing the risk of electrical connection between the top wall 101 and the first electrode terminal 20 causing internal short circuit of the cylindrical secondary battery 100.

[0062] 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 them. The first insulating member 30 has a higher melting point and can withstand higher temperatures, and the first insulating member 30 is not easy to melt, which is conducive to maintaining good insulation between the top wall 101 and the first electrode terminal 20, and further reducing the risk of short circuit in the cylindrical secondary battery 100 caused by electrical connection between the top wall 101 and the first electrode terminal 20.

[0063] 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 first insulating member 30 has a higher melting point and can withstand higher temperatures, and the first insulating member 30 is not easy to melt, which is conducive to maintaining good insulation between the top wall 101 and the first electrode terminal 20, and further reducing the risk of short circuit in the cylindrical secondary battery 100 caused by electrical connection between the top wall 101 and the first electrode terminal 20.

[0064] In one or more embodiments, t1≤ 1500℃. The first insulating member is easier to select and prepare under conditions that meet most high temperature environments, facilitating processing and production.

[0065] FIG. 3 is an enlarged view of A in FIG. 2, as shown in FIG. 3, the structure of the first insulating member 30 is not particularly limited in the present application, as long as the purpose of the application of the present application is achieved. In one or more embodiments, the cylindrical secondary battery 100 further comprises an electrode assembly 40, the electrode assembly 40 and the top wall 101 are arranged along the axial direction Y of the cylindrical secondary battery 100; the top wall 101 comprises a main body part 11 and a first extension part 12, the first extension part 12 comprises a first part 121 and a second part 122, the first part 121 extends from the main body part 11 along the axial direction Y of the cylindrical secondary battery 100, and the second part 122 extends from the first part 121 in the opposite direction of the radial direction X of the cylindrical secondary battery 100; the first insulating member 30 comprises a third part 31, the third part 31 extends along the axial direction Y of the cylindrical secondary battery 100, and at least part of the third part 31 is arranged between the first part 121 and the first electrode terminal 20 along the radial direction X of the cylindrical secondary battery 100, and the first part 121 and the first electrode terminal 20 form an insulating connection. The melting point of the first insulating member 30 is relatively high, and in a high temperature environment, the third part 31 is not easy to melt, which is conducive to maintaining good insulation between the top wall 101 and the first electrode terminal 20 along the radial direction X of the cylindrical secondary battery 100, and reducing the risk of short circuit in the cylindrical secondary battery 100 caused by electrical connection between the top wall 101 and the first electrode terminal 20.

[0066] The third part 31 extends along the axial direction Y of the cylindrical secondary battery 100, which is understood to mean that the third part 31 extends substantially along the axial direction Y of the cylindrical secondary battery 100, and the included angle between the extension direction of the third part 31 and the axial direction Y of the cylindrical secondary battery 100 is a1, -5°≤a1≤5°, for example, a1 can be: -5°, -4°, -3°, -2°, -1°, 0°, 1°, 2°, 3°, 4°, 5°, or a range formed by any two of them.

[0067] The first part 121 is used to limit the displacement of the third part 31 along the radial direction X of the cylindrical secondary battery 100, and the first part 121 extends substantially along the axial direction Y of the cylindrical secondary battery 100 from the main body part 11.

[0068] In one or more embodiments, the first insulating member 30 comprises a fourth part 32, the fourth part 32 extends from the third part 31 in the opposite direction of the radial direction X of the cylindrical secondary battery 100, and the fourth part 32 insulatingly connects the second part 122 and the first electrode terminal 20, and the melting point of the first insulating member 30 is relatively high, and in a high temperature environment, the fourth part 32 is not easy to melt, which is conducive to maintaining good insulation between the top wall 101 and the first electrode terminal 20 along the axial direction Y of the cylindrical secondary battery 100, and reducing the risk of short circuit in the cylindrical secondary battery 100 caused by electrical connection between the top wall 101 and the first electrode terminal 20.

[0069] The fourth portion 32 extends in the opposite direction of the radial direction X of the cylindrical secondary battery 100 from the third portion 31, and it is understood that the fourth portion 32 extends in the opposite direction of the radial direction X of the cylindrical secondary battery 100 from the third portion 31, the angle between the extending direction of the fourth portion 32 and the radial direction X of the cylindrical secondary battery 100 is α2, -5°≤α2≤5°, for example, α2 can be: -5°, -4°, -3°, -2°, -1°, 0°, 1°, 2°, 3°, 4°, 5°, or a range formed by any two of them.

[0070] In one or more embodiments, the angle between the extending direction of the third portion 31 and the extending direction of the fourth portion 32 is α3, 85°≤α3≤95°, for example, α3 can be: 85°, 86°, 87°, 88°, 89°, 90°, 91°, 92°, 93°, 94°, 95°, or a range formed by any two of them.

[0071] The second portion 122 of the first extending portion 12 is used to limit the displacement of the fourth portion 32 along the axial direction Y of the cylindrical secondary battery 100, and extends in the opposite direction of the radial direction X of the cylindrical secondary battery 100 from the first portion 121.

[0072] In one or more embodiments, along the radial direction X of the cylindrical secondary battery 100, the thickness of the third portion 31 is H1, 0.5mm≤H1≤1.5mm; for example, H1 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, or a range formed by any two of them. With the above thickness range of H1, on the one hand, along the radial direction X of the cylindrical secondary battery 100, it is beneficial to improve the insulation performance of the third portion 31, and maintain good insulation between the top wall 101 and the first electrode terminal 20. On the other hand, in a high temperature environment, the third portion 31 is not easy to melt, along the radial direction X of the cylindrical secondary battery 100, it is convenient to form a support between the first portion 121 and the first electrode terminal 20, and limit the radial X direction of the first electrode terminal 20, improve the position stability of the first electrode terminal 20 in the radial X direction of the cylindrical secondary battery 100, and prevent the problem of insulation failure caused by the first electrode terminal 20 shaking along the radial direction X.

[0073] In one or more embodiments, along the axial direction Y of the cylindrical secondary battery 100, the thickness of the fourth portion 32 is H2, and 0.5 mm≤H2≤1.5 mm. For example, H2 can be: 0.5 mm, 0.55 mm, 0.6 mm, 0.65 mm, 0.7 mm, 0.75 mm, 0.8 mm, 0.85 mm, 0.9 mm, 0.95 mm, 1.0 mm, 1.05 mm, 1.1 mm, 1.15 mm, 1.2 mm, 1.25 mm, 1.3 mm, 1.35 mm, 1.4 mm, 1.45 mm, 1.5 mm, or a range between any two of the above-mentioned H2 thicknesses. On the one hand, along the axial direction Y of the cylindrical secondary battery 100, the thickness of the fourth portion 32 is advantageous for improving the insulation performance of the fourth portion 32, and is advantageous for maintaining good insulation between the top wall 101 and the first electrode terminal 20. On the other hand, under high-temperature conditions, the fourth portion 32 is less likely to melt, and along the axial direction Y of the cylindrical secondary battery 100, the fourth portion 32 is advantageous for forming a support between the second portion 122 and the first electrode terminal 20, limiting the axial direction Y of the first electrode terminal 20, thereby being advantageous for improving the positional stability of the first electrode terminal 20 in the axial direction Y of the cylindrical secondary battery 100, and is less likely to cause problems such as insulation failure caused by axial Y shaking.

[0074] FIG. 4 is a structural schematic diagram of the top wall 101 of the cylindrical secondary battery 100 according to an embodiment of the present application, FIG. 5 is a structural schematic diagram of the top wall 101 of the cylindrical secondary battery 100 according to an embodiment of the present application, and FIG. 6 is a cross-sectional structural schematic diagram of the top wall 101 of the cylindrical secondary battery 100 according to an embodiment of the present application. Please refer to FIGS. 4, 5, and 6, in one or more embodiments, along the axial direction Y of the cylindrical secondary battery 100, at least one of the first portion 121 and the second portion 122 of the first extension 12 is projected as a ring shape, so as to facilitate limiting the first electrode terminal 20 from more angles and improving the positional stability of the first electrode terminal 20.

[0075] FIG. 7 is a structural schematic diagram of the first insulating member 30 of the cylindrical secondary battery 100 according to an embodiment of the present application, and FIG. 8 is a cross-sectional structural schematic diagram of the first insulating member 30 of the cylindrical secondary battery 100 according to an embodiment of the present application. Please refer to FIGS. 7 and 8, in one or more embodiments, along the axial direction Y of the cylindrical secondary battery 100, at least one of the third portion 31 and the fourth portion 32 is projected as a ring shape, which is advantageous for further improving the insulation between the top wall 101 and the first electrode terminal 20.

[0076] As shown in FIG. 3, in one or more embodiments, along the axial direction Y of the cylindrical secondary battery 100, the projection of the second portion 122 and the projection of the fourth portion 32 have an overlapping portion; the projection of the fourth portion 32 and the projection of the first electrode terminal 20 have an overlapping portion, so as to facilitate the positioning of the first insulating member 30 in the axial direction Y and the good positioning of the first electrode terminal 20.

[0077] In one or more embodiments, along the axial direction Y of the cylindrical secondary battery 100, the projection of the second portion 122 and the projection of the first electrode terminal 20 do not overlap (not shown), which is beneficial for saving the material of the second portion 122 and improving the weight energy density of the cylindrical secondary battery 100.

[0078] In one or more embodiments, along the axial direction Y of the cylindrical secondary battery 100, the projection of the second portion 122, the projection of the fourth portion 32 and the projection of the first electrode terminal 20 all have overlapping portions, which is beneficial for further enhancing the positioning of the first electrode terminal 20 in the axial direction Y.

[0079] The sealing structure of the cylindrical secondary battery 100 is not particularly limited in the present application, as long as the purpose of the present application is achieved.

[0080] As shown in FIG. 3, in one or more embodiments, the cylindrical secondary battery 100 further comprises a sealing member 50; the top wall 101 comprises a second extension 13, which extends in the opposite direction of the radial direction X of the cylindrical secondary battery 100 from the hole wall of the through hole 111; along the axial direction Y of the cylindrical secondary battery 100, at least part of the sealing member 50 is arranged between the second extension 13 and the first electrode terminal 20, which is beneficial for forming a sealed connection between the second extension 13 and the first electrode terminal 20.

[0081] In one or more embodiments, along the axial direction Y of the cylindrical secondary battery 100, the projection of the second extension 13 is annular, which provides good support force for the sealing member 50, so as to further improve the sealing stability between the second extension 13 and the first electrode terminal 20.

[0082] In one or more embodiments, the material of the sealing member 50 comprises fluororubber, which has good corrosion resistance and high temperature resistance, which is beneficial for improving the sealing effect of the cylindrical secondary battery 100 and reducing the probability of electrolyte leakage.

[0083] In one or more embodiments, along the axial direction Y of the cylindrical secondary battery 100, the thickness of the sealing member 50 is H3, i.e., the thickness of the sealing member 50 in the sealed state inside the cylindrical secondary battery 100, 0.5 mm≤H3≤2.3 mm. For example, H3 can be: 0.5 mm, 0.55 mm, 0.6 mm, 0.65 mm, 0.7 mm, 0.75 mm, 0.8 mm, 0.85 mm, 0.9 mm, 0.95 mm, 1.0 mm, 1.05 mm, 1.1 mm, 1.15 mm, 1.2 mm, 1.25 mm, 1.3 mm, 1.35 mm, 1.4 mm, 1.45 mm, 1.5 mm, 1.55 mm, 1.6 mm, 1.65 mm, 1.7 mm, 1.75 mm, 1.8 mm, 1.85 mm, 1.9 mm, 1.95 mm, 2.0 mm, 2.15 mm, 2.2 mm, 2.25 mm, 2.3 mm, or a range between any two of the foregoing values. The thickness of the fluororubber in the above range of H3 is conducive to providing a good sealing effect, and the thickness is relatively thin, which facilitates reducing the length of the cylindrical secondary battery 100, thereby facilitating improving the volumetric energy density of the cylindrical secondary battery 100.

[0084] In one or more embodiments, 0.5 mm≤H2≤1.5 mm, 1.2≤H3 / H2≤1.5. For example, H3 / H2 can be: 1.2, 1.22, 1.24, 1.26, 1.28, 1.3, 1.32, 1.34, 1.36, 1.38, 1.4, 1.42, 1.44, 1.46, 1.48, 1.5, or a range between any two of the foregoing values. Within the above range of H3 / H2, i.e., as the thickness of the first insulating member 30 increases, the thickness of the sealing member 50 is slightly greater than the thickness of the first insulating member 30. The sealing member 50 can be compressed to have a thickness slightly greater than the thickness of the first insulating member 30, which is conducive to matching the thickness of the first insulating member 30 and facilitating improving the sealing performance of the cylindrical secondary battery 100 under harsh working conditions such as impact or shaking.

[0085] In one or more embodiments, 0.5mm≤H3≤2.3mm, 1.2≤H3 / H2≤1.5. For example, H3 / H2 can be: 1.2, 1.22, 1.24, 1.26, 1.28, 1.3, 1.32, 1.34, 1.36, 1.38, 1.4, 1.42, 1.44, 1.46, 1.48, 1.5, or a range between any two of the foregoing values, within the range of the ratio described above, that is, as the thickness of the first insulating member 30 increases, the thickness of the sealing member 50 is slightly greater than the thickness of the first insulating member 30. The sealing member 50 can be compressed to keep the thickness of the sealing member 50 slightly greater than the thickness of the first insulating member 30, which is conducive to matching the thickness of the first insulating member 30, and is conducive to improving the sealing performance of the cylindrical secondary battery 100 under harsh working conditions such as impact or shaking.

[0086] In one or more embodiments, the first electrode terminal 20 is the negative electrode of the cylindrical secondary battery 100.

[0087] The application does not have special restrictions on the positive electrode setting mode of the cylindrical secondary battery 100. In one or more embodiments, the cylindrical secondary battery 100 further comprises: a second electrode terminal (not shown), the second electrode terminal is insulatedly connected with the shell 10, the second electrode terminal is electrically connected with the electrode assembly 40, the second electrode terminal is the positive electrode of the cylindrical secondary battery 100, and the shell 10 is neither the positive electrode nor the negative electrode of the cylindrical secondary battery 100. The cylindrical secondary battery 100 has the first electrode terminal 20 and the second electrode terminal, and is arranged at both ends of the cylindrical secondary battery 100. Since the distance is far, it is not easy to contact each other and short circuit.

[0088] In one or more embodiments, different from the above embodiments, in the present embodiment, the cylindrical secondary battery 100 does not arrange the second electrode terminal. The shell 10 is electrically connected with the electrode assembly 40, and the shell 10 is the positive electrode of the cylindrical secondary battery 100. That is, the shell 10 is electrically connected with the positive electrode of the electrode assembly 40 (for example, the positive electrode current collector plate is welded between the bottom wall of the shell 10 and the positive electrode of the electrode assembly 40, and the positive electrode current collector plate electrically connects the bottom wall of the shell 10 and the positive electrode of the electrode assembly 40), and the first electrode terminal 20 is electrically connected with the negative electrode of the electrode assembly 40, so that the shell 10 is the positive electrode of the cylindrical secondary battery 100, and the first electrode terminal 20 is the negative electrode of the cylindrical secondary battery 100. Since the second electrode terminal does not need to be arranged, the parts of the second electrode terminal are saved, the number of parts is reduced, the processing and assembly of the cylindrical secondary battery 100 are easy, and the overall battery is shortened, which is conducive to improving the energy density of the cylindrical secondary battery 100.

[0089] In the above embodiments, the cylindrical secondary battery 100 is a full-tab battery, and the electrode assembly 40 has different polarities at both ends along the axial direction Y.

[0090] In one or more embodiments, the electrode assembly 40 has a positive end facing the top wall 101 and a negative end facing away from the top wall 101.

[0091] In one or more embodiments, the electrode assembly 40 has a negative end facing the top wall 101 and a positive end facing away from the top wall 101.

[0092] Fig. 9 is a structural schematic diagram of the first electrode terminal 20 of the cylindrical secondary battery 100 according to an embodiment of the present application, and Fig. 10 is a sectional structural schematic diagram of the first electrode terminal 20 of the cylindrical secondary battery 100 according to an embodiment of the present application. In one or more embodiments, the first electrode terminal 20 includes a fifth portion 21, a sixth portion 22 and a seventh portion 23. The fifth portion 21 extends along the radial direction X of the cylindrical secondary battery 100 and is disposed between the sealing member 50 and the fourth portion 32 of the first insulating member 30. The sixth portion 22 extends from the fifth portion 21 away from the electrode assembly 40, and the seventh portion 23 is connected to the sixth portion 22 to form an end portion of the first electrode terminal 20 for external electrical connection.

[0093] Fig. 11 is a structural schematic diagram of the second insulating member 60 of the cylindrical secondary battery 100 according to an embodiment of the present application, and Fig. 12 is a sectional structural schematic diagram of the second insulating member 60 of the cylindrical secondary battery 100 according to an embodiment of the present application. In one or more embodiments, the cylindrical secondary battery 100 further includes a second insulating member 60. The second insulating member 60 includes an inner annular wall 61 disposed between the sixth portion 22 of the first electrode terminal 20 and the second portion 122 of the first extension 12 and extending along the axial direction Y of the cylindrical secondary battery 100 to form an insulating separation between the sixth portion 22 of the first electrode terminal 20 and the second portion 122 of the first extension 12, thereby reducing the probability of short circuit of the cylindrical secondary battery 100 caused by electrical connection between the sixth portion 22 of the first electrode terminal 20 and the second portion 122 of the first extension 12.

[0094] In one or more embodiments, the second insulating member 60 further includes an outer annular wall 62 disposed on a side of the first portion 121 of the first extension 12 away from the axis L0 of the cylindrical secondary battery 100 and extending along the axial direction Y of the cylindrical secondary battery 100, and a top annular wall 63 extending along the radial direction X of the cylindrical secondary battery 100 and connecting the outer annular wall 62 and the inner annular wall 61 to stably connect the outer annular wall 62 and the inner annular wall 61 to the top wall 101.

[0095] In one or more embodiments, the outer ring wall 62 and the top ring wall 63 cover the first extension 12, forming insulation protection for the first extension 12, which is conducive to reducing the risk of external components (such as busbars) short-circuiting the first extension 12 and the first electrode terminal 20.

[0096] Please refer to FIG. 2, FIG. 3, FIG. 9, FIG. 10 and FIG. 12, in one or more embodiments, the sixth part 22 of the first electrode terminal 20 is at least two, and the at least two sixth parts 22 are distributed along the outer periphery of the axis L0 of the cylindrical secondary battery 100, forming an opening 24 between the adjacent two sixth parts 22. As shown in FIG. 12, the second insulating member 60 further comprises a limiting part 64, which is extended by the inner ring wall 61 and extends into the opening 24. In the axial direction Y of the cylindrical secondary battery 100, the projection of the limiting part 64 overlaps with the projection of the seventh part 23 of the first electrode terminal 20, so that the seventh part 23 limits the second insulating member 60 in the axial direction Y of the cylindrical secondary battery 100, thereby reducing the risk of the second insulating member 60 being separated from the top wall 101.

[0097] As shown in FIG. 2 and FIG. 3, in one or more embodiments, a current cut-off device 70 is further included, which is electrically connected between the electrode assembly 40 and the first electrode terminal 20. The current cut-off device 70 is configured to be disconnected when the air pressure inside the shell 10 reaches a first threshold value, so as to disconnect the electrical connection between the electrode assembly 40 and the first electrode terminal 20, thereby breaking the charge-discharge circuit of the cylindrical secondary battery 100 and providing safety protection for the cylindrical secondary battery 100.

[0098] As shown in FIG. 2 and FIG. 3, in the above-mentioned embodiments, the current cut-off device 70 comprises a rupture disc 71 connected to the first electrode terminal 20 and a hole plate 72 connected to the electrode assembly 40, and the rupture disc 71 and the hole plate 72 are electrically connected. When the cylindrical secondary battery 100 fails, the air pressure inside the shell 10 rises, and when the air pressure inside the shell 10 reaches the first threshold value, the rupture disc 71 is pushed by the air pressure inside the shell 10, and the middle part of the rupture disc 71 is flipped towards the seventh part 23 of the first electrode terminal 20, and the rupture disc 71 is disconnected from the hole plate 72, so as to disconnect the electrical connection between the electrode assembly 40 and the first electrode terminal 20, thereby breaking the charge-discharge circuit of the cylindrical secondary battery 100 and providing safety protection for the cylindrical secondary battery 100.

[0099] In the above embodiment, when the cylindrical secondary battery 100 is in a severe working condition, such as external short circuit or high temperature environment, the temperature inside the shell 10 rises rapidly, and the air pressure inside the shell 10 rises rapidly. When the air pressure inside the shell 10 reaches the first threshold value, the current cutoff device 70 is disconnected, and the electrode assembly 40 and the first electrode terminal 20 are disconnected. When the temperature inside the shell 10 is high, the melting point of the first insulating member 30 is high, and the first insulating member 30 is not easy to melt in the temperature environment inside the shell 10. This is beneficial to the first insulating member 30 to maintain good insulation between the top wall 101 and the first electrode terminal 20, and to reduce the risk of the temperature or air pressure inside the cylindrical secondary battery 100 continuing to rise due to the top wall 101 and the first electrode terminal 20 still being electrically connected after the current cutoff device 70 is disconnected, causing the cylindrical secondary battery 100 to smoke or catch fire.

[0100] In one or more embodiments, the first threshold value is P1, and 1.0 MPa≤P1≤1.6 MPa. For example, P1 can 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 air pressure inside the shell 10 of the cylindrical secondary battery 100 rises to the range of P1, the current cutoff device 70 cuts off the electrical connection between the electrode assembly 40 and the first electrode terminal 20, which is beneficial to form an open circuit to the outside and improve the safety of the cylindrical secondary battery 100.

[0101] As shown in FIG. 2 and FIG. 3, in one or more embodiments, the current interruption device 70 includes a third insulating piece 73, the aperture plate 72 and the rupture disc 71 are arranged along the axial direction Y of the cylindrical secondary battery 100; wherein the aperture plate 72 includes an eighth portion 721 and a ninth portion 722, the eighth portion 721 surrounds the ninth portion 722, and the eighth portion 721 is electrically connected to the electrode assembly 40; the rupture disc 71 includes a tenth portion 711 and an eleventh portion 712, along the axial direction Y, a projection of the eleventh portion 712 surrounds a projection of the tenth portion 711, the eleventh portion 712 is electrically connected to the first electrode terminal 20, and the ninth portion 722 is electrically connected to the tenth portion 711; along the axial direction Y, at least a portion of the third insulating piece 73 is arranged between the eighth portion 721 and the eleventh portion 712; the melting point of the third insulating piece 73 is t2, and t2≥300℃. When the cylindrical secondary battery 100 is in a severe working condition such as external short circuit, the temperature in the shell 10 rapidly rises, the melting point of the third insulating piece 73 is relatively high, and the third insulating piece 73 is not easy to melt in a high-temperature environment, which is conducive to maintaining good insulation between the eighth portion 721 and the eleventh portion 712 of the third insulating piece 73 and reducing the risk of failure of the current interruption device 70.

[0102] In one or more embodiments, the melting point and material of the third insulating piece 73 are the same as the melting point and material of the first insulating piece 30.

[0103] In one or more embodiments, the cylindrical secondary battery 100 provided by the embodiments of the present application can be cyclically charged and discharged, so as to facilitate multiple uses of the cylindrical secondary battery 100. The present application does not have special restrictions on the type of cylindrical secondary battery 100, which can include any device that undergoes an electrochemical reaction. In one or more embodiments, the cylindrical secondary battery 100 includes but is not limited to a lithium-ion cylindrical secondary battery 100, so as to have a relatively high volumetric energy density, for example, the lithium-ion cylindrical secondary battery 100 includes but is not limited to a lithium cobalt oxide secondary battery, a ternary lithium secondary battery, a lithium iron phosphate secondary battery, or a lithium manganese acid secondary battery, etc.

[0104] In a second aspect, the embodiments of the present application provide a battery pack 200. FIG. 13 is a structural schematic diagram of the battery pack 200 provided by the embodiments of the present application. As shown in FIG. 13, 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, and the plurality of cylindrical secondary batteries 100 are connected in series or in parallel, or a combination of series and parallel connection.

[0105] In a third aspect, the present application provides a power consuming device 300, which includes at least one of the cylindrical secondary battery 100 or the battery pack 200 of any of the above embodiments.

[0106] In one or more embodiments, FIG. 14 is a structural schematic diagram of a first kind of power-using device provided by the embodiments of the present application, as shown in FIG. 14, the power-using device 300 includes the battery pack 200 in the above embodiments, and the battery pack 200 includes the cylindrical secondary battery 100 in the above embodiments.

[0107] In one or more embodiments, FIG. 15 is a structural schematic diagram of a second kind of power-using device provided by the embodiments of the present application, as shown in FIG. 15, the power-using device 300 includes the cylindrical secondary battery 100 in the above embodiments.

[0108] The power-using device is not particularly limited in the present application, and the power-using device includes the power-using device known in the prior art. For example, the power-using 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.

[0109] The above merely provides the preferred embodiments of the present application, but should not be used to limit the protective scope of the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protective scope of the present application.

Claims

1. A cylindrical secondary battery characterized by comprising: Comprising: a housing including a top wall having a through hole; a first electrode terminal, at least a portion of the first electrode terminal being disposed in the through hole; a first insulating member insulatingly connecting the top wall and the first electrode terminal; 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 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; the non-oxide ceramic includes 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, characterized by, Further comprising: an electrode assembly, the electrode assembly and the top wall being arranged in an axial direction of the cylindrical secondary battery; the top wall includes a main body portion and a first extension portion, the first extension portion includes a first portion and a second portion, the first portion extends from the main body portion in the axial direction of the cylindrical secondary battery, the second portion extends from the first portion in a direction opposite to a radial direction of the cylindrical secondary battery; the first insulating member includes a third portion, the third portion extends in the axial direction of the cylindrical secondary battery, at least a portion of the third portion is disposed between the first portion and the first electrode terminal in the radial direction of the cylindrical secondary battery. 7.The cylindrical secondary battery according to claim 6, wherein the first insulating member includes a fourth portion, the fourth portion extends from the third portion in the direction opposite to the radial direction of the cylindrical secondary battery, the fourth portion insulatingly connects the second portion and the first electrode terminal. 8.The cylindrical secondary battery according to claim 7, wherein in the radial direction of the cylindrical secondary battery, a thickness of the third portion is H1, 0.5mm≤H1≤1.5mm; and / or in the axial direction of the cylindrical secondary battery, a thickness of the fourth portion is H2, 0.5mm≤H2≤1.5mm. 9.The cylindrical secondary battery according to claim 7 or 8, wherein in the axial direction of the cylindrical secondary battery, a projection of the second portion and a projection of the fourth portion have an overlapping portion; the projection of the fourth portion and a projection of the first electrode terminal have an overlapping portion. 10.The cylindrical secondary battery according to claim 9, wherein in the axial direction of the cylindrical secondary battery, the projection of the second portion and the projection of the first electrode terminal have the overlapping portion. 11.The cylindrical secondary battery according to any one of claims 6 to 10, wherein the first electrode terminal includes a fifth portion, at least two sixth portions, and a seventh portion; The fifth part extends along a radial direction of the cylindrical secondary battery, the sixth part extends from the fifth part away from the electrode assembly, and an opening is formed between two adjacent sixth parts, and the seventh part connects the sixth parts and forms an end part of the first electrode terminal for external electrical connection. The cylindrical secondary battery further comprises a second insulating member, the second insulating member comprises an inner annular wall, the inner annular wall is arranged between the sixth part and the second part and extends along an axial direction of the cylindrical secondary battery to form an insulating separation between the sixth part and the second part.

12. The cylindrical secondary battery of claim 11, wherein The second insulating member further comprises an outer annular wall and a top annular wall, the outer annular wall is arranged on a side of the first part of the first extension away from the axis of the cylindrical secondary battery and extends along the axial direction of the cylindrical secondary battery; The top annular wall extends along a radial direction of the cylindrical secondary battery and connects the outer annular wall and the inner annular wall; and the outer annular wall and the top annular wall cover the first extension.

13. The cylindrical secondary battery of claim 11 or 12, wherein The second insulating member further comprises a limiting part, the limiting part extends from the inner annular wall and extends into the opening, and a projection of the limiting part overlaps with a projection of the seventh part along the axial direction of the cylindrical secondary battery.

14. The cylindrical secondary battery according to any one of claims 1 to 13, characterized by, Further comprising: a sealing member; The top wall comprises a second extension, the second extension extends from a hole wall of the through hole in a direction opposite to the radial direction of the cylindrical secondary battery; At least part of the sealing member is arranged between the second extension and the first electrode terminal along the axial direction of the cylindrical secondary battery.

15. The cylindrical secondary battery of claim 14, wherein A material of the sealing member comprises fluoro rubber.

16. The cylindrical secondary battery of claim 14 or 15, wherein A thickness of the sealing member is H3 and a thickness of the fourth part is H2 along the axial direction of the cylindrical secondary battery, 1.2≤H3 / H2≤1.5, and 0.5mm≤H3≤2.3mm.

17. The cylindrical secondary battery of claim 16, wherein 0.5mm≤H2≤1.5mm.

18. The cylindrical secondary battery according to any one of claims 1 to 17, characterized by, Further comprising: a current cut-off device; The current cut-off device is electrically connected to the electrode assembly and the first electrode terminal, and is configured to be disconnected when a gas pressure in the shell reaches a first threshold value, so as to disconnect the electrical connection between the electrode assembly and the first electrode terminal.

19. The cylindrical secondary battery of claim 18, wherein The current cut-off device comprises a rupture disc connected to the first electrode terminal and a hole plate connected to the electrode assembly, and the rupture disc and the hole plate are electrically connected.

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

21. A battery pack, characterized by, A cylindrical secondary battery including any one of the above claims 1 to 20.

22. An electrical device, comprising: A cylindrical secondary battery including any one of the above claims 1 to 20 or the battery pack of claim 21.

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