Cylindrical cell, battery pack and electric device

Abstract

Disclosed in the present application are a cylindrical cell, a battery pack and an electric device. The cylindrical cell comprises a casing, an electrode assembly, an end cap and a first insulating member. The end cap is connected to the casing and the electrode assembly. The end cap and the electrode assembly are arranged in an axial direction. The end cap is provided with a projecting portion. The first insulating member comprises a first part and a second part which are connected to each other, wherein the first part is connected to the end cap and the casing; and in the axial direction, at least part of the second part is located between the projecting portion and the electrode assembly, and is connected to the projecting portion and the electrode assembly.

Description

Cylindrical batteries, battery packs and electrical devices Technical Field

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

[0002] With the rapid development of the lithium battery industry, its application in electric vehicles, electric bicycles, and power tools has become an inevitable trend. Cylindrical batteries, due to their advantages such as good packability and high stability, are highly favored and are increasingly being used in various complex scenarios. The harsh operating conditions of different application scenarios have led to increasingly higher performance requirements for cylindrical batteries. Summary of the Invention

[0003] In view of the above situation, it is necessary to provide a cylindrical battery that helps to suppress the movement of its internal electrode components and improve the shock resistance and drop resistance of the cylindrical battery.

[0004] Embodiments of this application provide a cylindrical battery, including a housing, an electrode assembly, an end cap, and a first insulating member. The housing has a receiving cavity, in which the electrode assembly is disposed. The end cap connects the housing and the electrode assembly, and the end cap and the electrode assembly are arranged along the axial direction of the cylindrical battery. The end cap has a protrusion extending toward the electrode assembly. The first insulating member includes a first portion and a second portion interconnected with each other. The first portion connects the end cap and the housing along the axial direction, and at least a portion of the second portion is located between the protrusion and the electrode assembly, and connects the protrusion and the electrode assembly.

[0005] In the cylindrical battery described above, the end cap has a protrusion extending toward the electrode assembly, and along the axial direction, at least a portion of the second part of the first insulating member is located between the protrusion and the electrode assembly. When the electrode assembly moves, the protrusion can press against the electrode assembly through the first insulating member, which helps to improve the shock resistance and drop resistance of the cylindrical battery and extend the service life of the cylindrical battery.

[0006] In one or more embodiments of this application, the housing includes a sidewall, at least a portion of the first part is located between the end cap and the sidewall, and connects the end cap and the sidewall, which helps to improve the sealing effect between the housing and the end cap and improve the safety performance of the cylindrical battery.

[0007] In one or more embodiments of this application, the sidewall includes a recess that is recessed toward the axis of the cylindrical battery and is insulated from the electrode assembly. Along the axial direction, the projection of the recess and the projection of the electrode assembly overlap. When the electrode assembly shifts, the recess can restrain the electrode assembly by pressing against it, which helps improve the shock resistance and drop resistance of the cylindrical battery and extends its service life.

[0008] In one or more embodiments of this application, along the axial direction, the projection of the concave portion surrounds the projection of the convex portion, and the projection of the concave portion is separate from the projection of the convex portion. When the electrode assembly shifts, the position where the convex portion presses against the electrode assembly through the first insulating member is different from the position where the concave portion presses against the electrode assembly. This is beneficial to increase the area of ​​pressing against the electrode assembly, thereby improving the limiting effect on the electrode assembly, improving the shock resistance and drop resistance of the cylindrical battery, and also helping to reduce the risk of the concave portion squeezing the convex portion, thus extending the service life of the cylindrical battery.

[0009] In one or more embodiments of this application, along the axial direction, the projection of the recess surrounds the projection of the second portion, and the projection of the recess is separate from the projection of the second portion. When the electrode assembly shifts, the position where the second portion presses against the electrode assembly is different from the position where the recess presses against the electrode assembly. This is beneficial to increase the area of ​​pressing against the electrode assembly, thereby improving the limiting effect on the electrode assembly, improving the shock resistance and drop resistance of the cylindrical battery, and also helping to reduce the risk of the recess squeezing the second portion, thus extending the service life of the cylindrical battery.

[0010] In one or more embodiments of this application, the second portion does not extend beyond the recess along the axial direction. When the electrode assembly shifts, the impact force generated by the shifting electrode assembly acts first on the recess, or simultaneously on the recess and the second portion. This helps the recess withstand the impact force, reduces the impact force on the structure located in the middle region of the top of the cylindrical battery, and lowers the risk of damage to the structure located in the middle region of the top of the cylindrical battery caused by the impact force.

[0011] In one or more embodiments of this application, the end of the recess extends beyond the end face of the second portion along the axial direction.

[0012] In one or more embodiments of this application, the end cap includes a base, a portion of which protrudes axially and forms a protrusion.

[0013] In one or more embodiments of this application, the base includes a first plane facing the electrode assembly. Along the axial direction, a protrusion extends beyond the first plane. The length of the protrusion extending beyond the first plane is defined as T, where 1mm≤T≤1.3mm. This is beneficial for limiting the protrusion when the electrode assembly moves, thereby improving the shock resistance and drop resistance of the cylindrical battery. At the same time, it is also beneficial for reducing the impact of the end cap on the length of the cylindrical battery, thereby improving the space utilization and energy density of the cylindrical battery.

[0014] In one or more embodiments of this application, the end cap further includes a connecting portion that connects to the base and extends in a direction opposite to the axial direction; the base includes a first region and a second region, a protrusion that connects the first region and the second region, the first region that connects to the connecting portion, and the second region that connects to the first portion, the protrusion being located between the first region and the second region, which is beneficial to improving the structural rigidity of the base, reducing the risk of base deformation, and improving the pressing and limiting effect of the protrusion on the electrode assembly.

[0015] In one or more embodiments of this application, along the axial direction, the first region is closer to the electrode assembly than the second region, which is beneficial to reducing the height of the connection relative to the electrode assembly, thereby reducing the length of the cylindrical battery and increasing the volumetric energy density of the cylindrical battery.

[0016] In one or more embodiments of this application, the projection of the protrusion is located within the projection of the second part along the axial direction. When the electrode assembly shifts, the protrusion limits the electrode assembly through the second part. At this time, the entire axial end face of the protrusion presses against the second part, which helps the second part support the protrusion and transmit pressure to the electrode assembly, promotes uniform pressure distribution, reduces the risk of stress concentration in the second part, and extends the service life of the first insulating element.

[0017] In one or more embodiments of this application, along the axial direction, the area of ​​the projected region of the protrusion is defined as S1, and the area of ​​the electrode assembly is defined as S2, where 0.04 ≤ S1 / S2 ≤ 0.3. When the electrode assembly shifts, the ratio of the projected area S1 of the protrusion to the projected area S2 of the electrode assembly satisfies this range, which is beneficial to improving the limiting effect of the protrusion on the electrode assembly, reducing the impact of the protrusion width on the utilization rate of the cavity space, reducing the impact of the protrusion width on the energy density of the cylindrical battery, and reducing the risk of the first insulating member coming into contact with the recess and being squeezed by the recess, thereby extending the service life of the first insulating member.

[0018] In one or more embodiments of this application, 0.06≤S1 / S2≤0.3 is beneficial to further improve the limiting effect of the protrusion on the electrode assembly, and also takes into account the impact of the protrusion width on the utilization rate of the cavity space.

[0019] In one or more embodiments of this application, 0.18≤S1 / S2≤0.24 is beneficial to further improve the limiting effect of the protrusion on the electrode assembly and reduce the impact of the protrusion width on the utilization rate of the cavity space.

[0020] In one or more embodiments of this application, the width of the protrusion is defined as L1 along the radial direction of the cylindrical battery, where 0.7mm≤L1≤11.1mm. This is beneficial for balancing the limiting effect of the protrusion on the electrode assembly and reducing the impact of the protrusion on the space utilization and energy density of the cylindrical battery.

[0021] In one or more embodiments of this application, along the axial direction, the area of ​​the projected region of the protrusion is defined as S1, and the area of ​​the projected region of the base is defined as S3, where 0.06 ≤ S1 / S3 ≤ 0.45. When the electrode assembly shifts, the ratio of the area S1 of the projected region of the protrusion to the area S3 of the projected region of the base satisfies this range, which is beneficial to improving the limiting effect of the protrusion on the electrode assembly, reducing the impact of the protrusion width on the utilization rate of the cavity space, reducing the impact of the protrusion width on the energy density of the cylindrical battery, and reducing the risk of the first insulating member coming into contact with the recess and being squeezed by the recess, thereby extending the service life of the first insulating member.

[0022] In one or more embodiments of this application, 0.09≤S1 / S3≤0.36 is beneficial to both improve the limiting effect of the protrusion on the electrode assembly and reduce the impact of the protrusion width on the utilization rate of the cavity space.

[0023] In one or more embodiments of this application, the cylindrical battery further includes a second insulating member disposed within the receiving cavity. Along the axial direction, a portion of the second insulating member is located between the recess and the electrode assembly, connecting the recess and the electrode assembly. The second insulating member not only provides insulation and protection, reducing the risk of short circuits between the casing and the electrode assembly, but also acts as a filler, ensuring axial insulation between the recess and the electrode assembly. When the electrode assembly shifts, the recess, through the second insulating member, can limit the movement of the electrode assembly, improving the cylindrical battery's shock resistance and drop resistance. Furthermore, the recess, through the second insulating member, can increase the pressure area on the electrode assembly, enhancing the effect of suppressing electrode assembly shift.

[0024] In one or more embodiments of this application, along the axial direction, at least a portion of the second part is located between the protrusion and the second insulating member, and the second part connects the protrusion and the second insulating member. When the electrode assembly shifts, the protrusion can press against the electrode assembly through the second part and the second insulating member, restricting the movement of the electrode assembly. Furthermore, the second part of the first insulating member and the second insulating member serve as an intermediate medium, which not only provides a buffering effect but also reduces the risk of damage to the electrode assembly.

[0025] In one or more embodiments of this application, the projection of the second portion is located within the projection of the second insulating member along the axial direction. When the electrode assembly shifts, the protrusion acts as a limiter for the electrode assembly through the second portion and the second insulating member. At this time, the entire axial end face of the second portion presses against the second insulating member, which helps the second insulating member support the second portion and transmit pressure to the electrode assembly, promotes uniform pressure distribution, reduces the risk of stress concentration in the second insulating member, and extends the service life of the second insulating member.

[0026] In one or more embodiments of this application, the cylindrical battery further includes a current collector, which is disposed in the receiving cavity and connects the electrode assembly and the end cap. By providing a current collector to connect the electrode assembly and the end cap, it is convenient to realize the electrical connection between the end cap and the electrode assembly, which helps to simplify the assembly process of the cylindrical battery.

[0027] In one or more embodiments of this application, the cylindrical battery further includes an explosion-proof sheet disposed within the receiving cavity. The explosion-proof sheet is located on the side of the current collector facing away from the electrode assembly. The explosion-proof sheet connects the current collector and the end cap. A portion of the explosion-proof sheet is located between the end cap and the second portion, and connects the end cap and the second portion. When the gas pressure inside the receiving cavity exceeds the upper limit that the explosion-proof sheet can withstand, the gas inside the receiving cavity can rupture the explosion-proof sheet, thereby achieving the purpose of pressure relief. This helps to reduce the risk of the cylindrical battery exploding due to excessive internal gas pressure and improves the safety performance of the cylindrical battery.

[0028] In one or more embodiments of this application, the diameter of the cylindrical battery ranges from 30 to 100 mm. A larger diameter is beneficial for increasing the capacity of the cylindrical battery. At the same time, the end cap protrusion helps to suppress the movement of the electrode assembly and extend the service life of the cylindrical battery.

[0029] Embodiments of this application also provide a battery pack, including the cylindrical battery of any of the foregoing embodiments.

[0030] In the aforementioned battery pack, the cylindrical battery has an end cap with a protrusion extending toward the electrode assembly. Along the axial direction, at least a portion of the second part of the first insulating member is located between the protrusion and the electrode assembly. When the electrode assembly moves, the protrusion can press against the electrode assembly through the first insulating member, restricting the movement of the electrode assembly. This is beneficial for improving the shock resistance and drop resistance of the cylindrical battery, thereby improving the shock resistance and drop resistance of the battery pack.

[0031] Embodiments of this application also provide an electrical device, including the cylindrical battery of any of the foregoing embodiments, or the aforementioned battery pack.

[0032] Among the aforementioned electrical devices, cylindrical batteries or battery packs have better shock resistance and drop resistance, which helps improve the compatibility of electrical devices with different application scenarios. Attached Figure Description

[0033] Figure 1 is a schematic diagram of the structure of a cylindrical battery in one embodiment of this application.

[0034] Figure 2 is an exploded view of a cylindrical battery in one embodiment of this application.

[0035] Figure 3 is a cross-sectional view of the central axis of a cylindrical battery in one embodiment of this application.

[0036] Figure 4 is a magnified view of region IV in Figure 3.

[0037] Figure 5 is a schematic diagram of the end cap structure in one embodiment of this application.

[0038] Figure 6 is a cross-sectional view of the end cap in one embodiment of this application.

[0039] Figure 7 is a schematic diagram of the battery pack structure in one embodiment of this application.

[0040] Figure 8 is a schematic diagram of the structure of an electrical device in one embodiment of this application.

[0041] Reference numerals: Cylindrical battery 100, Casing 10, Side wall 11, Recess 111, Bending section 112, Bottom wall 12, Receiving cavity 13, Electrode assembly 20, First electrode 21, First flattened portion 211, Second electrode 22, Second flattened portion 221, Separator 23, End cap 30, Base 31, First plane 311, First region 312, Second region 313, Protrusion 32, Connecting portion 33, First insulator 42, Second insulator 41, First part 421, Second part 422, Current collector 50, Explosion-proof sheet 60, Groove 61, Bending structure 62, First structural component 71, Through hole711 Second structural component 72 Axis 80 Battery pack 200 Electrical equipment 300 Axial X

[0042] The following detailed description, in conjunction with the accompanying drawings, will further illustrate this application. Detailed Implementation

[0043] The technical solutions of the embodiments of this application will be described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments.

[0044] It should be noted that when an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be an intervening element. When an element is considered to be "set" on another element, it can be directly set on the other element or there may be an intervening element. In this application, unless otherwise expressly specified and limited, the terms "installed," "connected," "linked," "fixed," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances. The term "and / or" as used herein includes any and all combinations of one or more of the related listed items.

[0045] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0046] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0047] In the description of the embodiments of this application, the term "perpendicular" is used to describe the ideal state between two components. In actual production or use, two components may exist in a state that is approximately perpendicular. For example, combined with numerical description, perpendicular can refer to the angle between two straight lines within the range of 90±10°, perpendicular can also refer to the dihedral angle between two planes within the range of 90°±10°, and perpendicular can also refer to the angle between a straight line and a plane within the range of 90±10°. The two components described as "perpendicular" do not have to be absolutely straight lines or planes, but can be approximately straight lines or planes. From a macroscopic perspective, if the overall extension direction is a straight line or plane, the component can be considered a "straight line" or "plane".

[0048] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. Where there is no conflict, the various embodiments in this application can be combined with each other.

[0049] It should be noted that the thickness, length, width, and other dimensions of various components in the embodiments of this application shown in the accompanying drawings, as well as the overall thickness, length, width, and other dimensions of the integrated device, are merely illustrative examples and should not constitute any limitation on this application.

[0050] Embodiments of this application provide a cylindrical battery, including a housing, an electrode assembly, an end cap, and a first insulating member. The housing has a receiving cavity, in which the electrode assembly is disposed. The end cap connects the housing and the electrode assembly, and the end cap and the electrode assembly are arranged along the axial direction of the cylindrical battery. The end cap has a protrusion extending toward the electrode assembly. The first insulating member includes a first portion and a second portion interconnected with each other. The first portion connects the end cap and the housing along the axial direction, and at least a portion of the second portion is located between the protrusion and the electrode assembly, and connects the protrusion and the electrode assembly.

[0051] In the cylindrical battery described above, the end cap is provided with a protrusion extending toward the electrode assembly, and at least a portion of the second part of the first insulating member is located between the protrusion and the electrode assembly. When the electrode assembly moves, the protrusion can press against the electrode assembly through the first insulating member, which is beneficial to improving the shock resistance and drop resistance of the cylindrical battery and extending the service life of the cylindrical battery.

[0052] The embodiments of this application will be further described below with reference to the accompanying drawings.

[0053] As shown in Figures 1 to 3, an embodiment of this application provides a cylindrical battery 100, including a housing 10, an electrode assembly 20, and an end cap 30. The housing 10 has a receiving cavity 13, the electrode assembly 20 is disposed in the receiving cavity 13, and the end cap 30 connects the housing 10 and the electrode assembly 20. The end cap 30 and the electrode assembly 20 are arranged along the axial direction X of the cylindrical battery 100.

[0054] In one embodiment, the housing 10 includes a sidewall 11 and a bottom wall 12 connected to each other. The sidewall 11 is connected to an end cap 30, and the bottom wall 12 is connected to an electrode assembly 20. The electrode assembly 20 and the bottom wall 12 are arranged along the axial direction X. The electrode assembly 20 and the bottom wall 12 are electrically connected, and the electrode assembly 20 and the end cap 30 are electrically connected. The end cap 30 and the sidewall 11 are insulated from each other. The end cap 30 and the housing 10 form the positive and negative terminals of the cylindrical battery 100. The cylindrical battery 100 is electrically connected to an external device through the end cap 30 and the housing 10, thereby enabling charging or discharging.

[0055] In one embodiment, both the housing 10 and the end cap 30 are made of metal, which helps to improve the current carrying capacity of the cylindrical battery 100 and reduce the risk of deformation or damage to the housing 10, thereby improving the reliability of the cylindrical battery 100.

[0056] As shown in Figures 2 to 4, in one embodiment, the cylindrical battery 100 further includes a first insulating member 42. The first insulating member 42 includes a first portion 421, at least a portion of which is located between the end cap 30 and the side wall 11, connecting the end cap 30 and the side wall 11. The first portion 421 can provide insulation and sealing between the end cap 30 and the side wall 11, reducing the risk of short circuit between the end cap 30 and the side wall 11, reducing the risk of electrolyte leakage in the receiving cavity 13, and reducing the risk of external impurities entering the receiving cavity 13 of the housing 10.

[0057] In one embodiment, the material of the first insulating element 42 includes, but is not limited to, any one of polybutylene terephthalate (PBT), polypropylene (PP), and polyphenylene sulfide (PPS), which helps the first insulating element 42 to play the role of insulation protection and sealing.

[0058] In one embodiment, the sidewall 11 includes a recess 111 recessed toward the axis 80 of the cylindrical battery 100. The recess 111 is insulated from the electrode assembly 20, and the projection of the recess 111 and the projection of the electrode assembly 20 overlap along the axial direction X. When the electrode assembly 20 shifts, the recess 111, by connecting to the electrode assembly 20, can restrict the movement of the electrode assembly 20 in a direction away from the bottom wall 12, thereby improving the shock resistance and drop resistance of the cylindrical battery 100.

[0059] In one embodiment, the cylindrical battery 100 further includes a second insulating member 41. The second insulating member 41 is disposed in the receiving cavity 13 and located on the side of the electrode assembly 20 away from the bottom wall 12, along the axial direction X. A portion of the second insulating member 41 is located between the recess 111 and the electrode assembly 20, connecting the recess 111 and the electrode assembly 20. The second insulating member 41 not only provides insulation and protection, reducing the risk of short circuit between the housing 10 and the electrode assembly 20, but also acts as a filler, making the recess 111 insulated from the electrode assembly 20 along the axial direction X. When the electrode assembly 20 shifts, the recess 111, through the second insulating member 41, can limit the movement of the electrode assembly 20 in the direction away from the bottom wall 12, improving the shock resistance and drop resistance of the cylindrical battery 100. Furthermore, the recess 111, through the second insulating member 41, can also increase the pressing area of ​​the electrode assembly 20, improving the effect of suppressing the shifting of the electrode assembly 20.

[0060] In one embodiment, the second insulating member 41 is an annular insulating pad with a through hole in the thickness direction in the central region of the annular pad to facilitate the exposure of the flattened portion.

[0061] In one embodiment, the material of the second insulating member 41 includes, but is not limited to, any one of polybutylene terephthalate (PBT), polypropylene (PP), and polyphenylene sulfide (PPS), which helps the second insulating member 41 to play an insulating and protective role, as well as an elastic buffering role, reducing the risk of damage to the electrode assembly 20.

[0062] In one embodiment, the end cap 30 is provided with a protrusion 32 that extends toward the electrode assembly 20. When the electrode assembly 20 moves, the protrusion 32 presses against the electrode assembly 20, which can restrict the movement of the electrode assembly 20 in a direction away from the bottom wall 12, thereby improving the shock resistance and drop resistance of the cylindrical battery 100.

[0063] In one embodiment, the first insulating member 42 further includes a second portion 422 connected to the first portion 421 along the axial direction X. At least a portion of the second portion 422 is located between the protrusion 32 and the electrode assembly 20. When the electrode assembly 20 shifts, the protrusion 32 can press against the electrode assembly 20 through the second portion 422, restricting the movement of the electrode assembly 20. Furthermore, the second portion 422 of the first insulating member 42 acts as an intermediate medium, providing not only a buffering effect but also reducing the risk of damage to the electrode assembly 20.

[0064] In one embodiment, along the axial direction X, at least a portion of the second portion 422 is located between the protrusion 32 and the second insulator 41, and the second portion 422 connects the protrusion 32 and the second insulator 41. When the electrode assembly 20 shifts, the protrusion 32 can press against the electrode assembly 20 through the second portion 422 and the second insulator 41, restricting the movement of the electrode assembly 20. Furthermore, the second portion 422 of the first insulator 42 and the second insulator 41 serve as an intermediate medium, which not only provides a buffering effect but also reduces the risk of damage to the electrode assembly 20.

[0065] In one embodiment, the protrusion 32 and the recess 111 can be fitted together, with the protrusion 32 and the recess 111 pressing against different positions of the electrode assembly 20 to improve the limiting effect on the electrode assembly 20 and improve the shock resistance and drop resistance of the cylindrical battery 100.

[0066] In one embodiment, along the axial direction X, the projection of the recess 111 surrounds the projection of the protrusion 32, and the projection of the recess 111 is separate from the projection of the protrusion 32. When the electrode assembly 20 shifts, the position where the protrusion 32 presses against the electrode assembly 20 is different from the position where the recess 111 presses against the electrode assembly 20. This helps to increase the area of ​​pressing against the electrode assembly 20, thereby improving the limiting effect on the electrode assembly 20, improving the shock resistance and drop resistance of the cylindrical battery 100, and also helps to reduce the risk of the recess 111 squeezing the protrusion 32, thus extending the service life of the cylindrical battery 100.

[0067] In one embodiment, along the axial direction X, the projection of the recess 111 surrounds the projection of the second portion 422, and the projection of the recess 111 is separate from the projection of the second portion 422. When the electrode assembly 20 shifts, the position where the second portion 422 presses against the electrode assembly 20 is different from the position where the recess 111 presses against the electrode assembly 20. This helps to increase the area of ​​pressing against the electrode assembly 20, thereby improving the limiting effect on the electrode assembly 20, improving the shock resistance and drop resistance of the cylindrical battery 100, and also helps to reduce the risk of the recess 111 squeezing the second portion 422, thus extending the service life of the cylindrical battery 100.

[0068] In one embodiment, the end cap 30 includes a base 31, a portion of which protrudes axially X to form a protrusion 32. In one embodiment, the protrusion 32 is formed from the base 31 by stamping.

[0069] In one embodiment, the end cap 30 further includes a connecting portion 33, which connects to the base 31 and extends in a direction opposite to the axial direction X. The connecting portion 33 can serve as a terminal of the cylindrical battery 100 for connecting to external devices.

[0070] In one embodiment, a portion of the connecting portion 33 extends beyond the sidewall 11 in a direction opposite to the axial direction X, facilitating the connection of the connecting portion 33 to an external structure.

[0071] In one embodiment, at least a portion of the structure of the first part 421 is located between the base 31 and the sidewall 11 to provide insulation and sealing, thereby reducing the risk of short circuits and leakage in the housing 10 and the end cap 30.

[0072] In one embodiment, the end of the sidewall 11 is bent toward the axis 80 in a direction opposite to the axial direction X, forming a bent segment 112. The bent segment 112 and the recess 111 are arranged along the axial direction X, and the radially upward end of the base 31 is located between the bent segment 112 and the recess 111. Furthermore, a portion of the structure of the first portion 421 is located between the bent segment 112 and the base 31, and a portion of the structure of the first portion 421 is located between the recess 111 and the base 31. The first portion 421 connects the bent segment 112 and the base 31, and the first portion 421 connects the recess 111 and the base 31. In this embodiment, the sidewall 11 can limit the first insulating member 42 and the base 31 through its own structure, improving the connection stability and reliability between the housing 10 and the end cap 30, enhancing the shock resistance and drop resistance of the cylindrical battery 100, and simplifying the limiting structure of the end cap 30, reducing the number of accessories of the cylindrical battery 100, saving the cost of the cylindrical battery 100, and improving the space utilization and energy density of the cylindrical battery 100. Simultaneously, this embodiment also helps to increase the connection area between the first insulating member 42 and the sidewall 11, and the connection area between the first insulating member 42 and the end cap 30, improving the sealing effect of the first insulating member 42.

[0073] Radial refers to the direction from the axis 80 of the cylindrical battery 100 toward the sidewall 11.

[0074] In one embodiment, the end cap 30 is made by a stamping process, which helps to simplify the processing and manufacturing process of the end cap 30, save the manufacturing cost of the end cap 30, and thus save the cost of the cylindrical battery 100.

[0075] In one embodiment, the end face of the protrusion 32 along the axial direction X is perpendicular to the axial direction X, which is beneficial for the protrusion 32 to apply a uniform force to the electrode assembly 20 and improve the limiting effect on the electrode assembly 20.

[0076] In one embodiment, the second portion 422 does not extend beyond the recess 111 along the axial direction X. When the electrode assembly 20 shifts, the impact force generated by the shifting of the electrode assembly 20 acts first on the recess 111, or simultaneously on the recess 111 and the second portion 422. This helps the recess 111 withstand the impact force, reducing the impact force on the structure located in the middle region of the top of the cylindrical battery 100 (e.g., the end cap 30 and other parts adjacent to the end cap 30), and reducing the risk of damage to the structure located in the middle region of the top of the cylindrical battery 100 caused by the impact force.

[0077] In one embodiment, the sidewall 11 is made of metal and the first insulating member 42 is made of polymer material. The metal material has greater impact resistance. When the electrode assembly 20 moves, the recess 111 of the sidewall 11 first bears the impact force of the electrode assembly 20, which helps to improve the service life of the second part 422 of the first insulating member 42.

[0078] In one embodiment, along the axial direction X, the end face of the second portion 422 is flush with the end region of the recess 111.

[0079] In one embodiment, along the axial direction X, the end of the recess 111 extends beyond the end face of the second portion 422.

[0080] In one embodiment, along the axial direction X, a portion of the structure of the second part 422 extends beyond the recess 111. In one embodiment, the dimension by which the second part 422 extends beyond the recess 111 along the axial direction X is no greater than 0.5 mm. When the electrode assembly 20 moves, the second part 422 undergoes elastic deformation, providing a buffer area. This helps to reduce the impact of the electrode assembly 20's movement on the structure located in the middle region of the top of the cylindrical battery 100, and reduces the risk of damage to the structure located in the middle region of the top of the cylindrical battery 100 due to impact forces.

[0081] As shown in Figures 3 to 6, in one embodiment, the base 31 includes a first plane 311 facing the electrode assembly 20. Along the axial direction X, a protrusion 32 extends beyond the first plane 311. The length of the protrusion 32 extending beyond the first plane 311 is defined as T, where 1 mm ≤ T ≤ 1.3 mm. The range of values ​​for the length T of the protrusion 32 extending beyond the first plane 311 is beneficial for limiting the movement of the protrusion 32 when the electrode assembly 20 shifts, thereby improving the shock resistance and drop resistance of the cylindrical battery 100. At the same time, the range of values ​​for the length T of the protrusion 32 extending beyond the first plane 311 also helps to reduce the impact of the end cap 30 on the length of the cylindrical battery 100, thereby improving the space utilization and energy density of the cylindrical battery 100.

[0082] In one embodiment, the length T of the protrusion 32 extending beyond the first plane 311 is any one of 1 mm, 1.05 mm, 1.1 mm, 1.15 mm, 1.2 mm, 1.25 mm, and 1.3 mm.

[0083] In one embodiment, the base 31 includes a first region 312 and a second region 313, and a protrusion 32 connects the first region 312 and the second region 313. The first region 312 is connected to the connecting portion 33, and the second region 313 is connected to the first portion 421. The protrusion 32 is located between the first region 312 and the second region 313, which helps to improve the structural rigidity of the base 31, reduce the risk of deformation of the base 31, and improve the pressing and limiting effect of the protrusion 32 on the electrode assembly 20.

[0084] In one embodiment, the distance between the first region 312 and the electrode assembly 20 along the axial direction X is the same as the distance between the second region 313 and the electrode assembly 20, which is beneficial for the forming process of the protrusion 32.

[0085] In one embodiment, along the axial direction X, the first region 312 is closer to the electrode assembly 20 than the second region 313, meaning the distance between the first region 312 and the electrode assembly 20 is smaller than the distance between the second region 313 and the electrode assembly 20. This facilitates reducing the height of the connecting portion 33 relative to the electrode assembly 20, thereby reducing the length of the cylindrical battery 100 and increasing the volumetric energy density of the cylindrical battery 100. In this case, T is the length of the protrusion 32 extending beyond the first region 312.

[0086] In one embodiment, the thickness L3 of the base 31 along the axial direction X is 0.8-1 mm, which is beneficial to balance the structural strength of the base 31 and reduce the impact of the thickness of the base 31 on the length of the cylindrical battery 100.

[0087] In one embodiment, the thickness of the first region 312 and the thickness of the second region 313 are both L3. In this case, the thickness L3 of the base 31 along the axial direction X is either the thickness of the first region 312 or the thickness of the second region 313.

[0088] In one embodiment, the thickness of the first region 312 is different from the thickness of the second region 313. In this case, the thickness L3 of the base 31 along the axial direction X is the thickness of the second region 313.

[0089] In one embodiment, along the axial direction X, the projection of the protrusion 32 lies within the projection of the second portion 422. When the electrode assembly 20 shifts, the protrusion 32, through the second portion 422 and the second insulating member 41, limits the electrode assembly 20, which helps the second portion 422 support the protrusion 32 and transmit pressure to the second insulating member 41, promotes uniform pressure distribution, reduces the risk of stress concentration in the second portion 422, and extends the service life of the first insulating member 42.

[0090] The projection of the protrusion 32 along the axial direction X refers to the projection of the upper end face of the protrusion 32 along the axial direction X, excluding the projections of other parts of the protrusion 32.

[0091] In one embodiment, along the axial direction X, the projection of the second portion 422 lies within the projection of the second insulating member 41. When the electrode assembly 20 shifts, the protrusion 32, through the second portion 422 and the second insulating member 41, limits the electrode assembly 20. At this time, the entire end face of the second portion 422 along the axial direction X presses against the second insulating member 41, which is beneficial for the second insulating member 41 to support the second portion 422 and transmit pressure to the electrode assembly 20, promotes uniform pressure distribution, reduces the risk of stress concentration in the second insulating member 41, and extends the service life of the second insulating member 41.

[0092] In one embodiment, the width of the protrusion 32 is defined as L1 along the radial direction of the cylindrical battery 100, where 0.7mm≤L1≤11.1mm. This is beneficial for improving the limiting effect of the protrusion 32 on the electrode assembly 20, reducing the impact of the width of the protrusion 32 on the space utilization rate within the cavity 13, reducing the impact of the width of the protrusion 32 on the energy density of the cylindrical battery 100, and reducing the risk of the first insulating member 42 coming into contact with the recess 111 and being squeezed by the recess 111, thereby extending the service life of the first insulating member 42.

[0093] Wherein, the radial width L1 of the protrusion 32 refers to the width of the end face of the protrusion 32 along the axial direction X.

[0094] In one embodiment, the width L1 of the protrusion 32 is any one of 0.7mm, 1mm, 1.1mm, 1.6mm, 2mm, 2.1mm, 2.3mm, 2.7mm, 3mm, 3.3mm, 4mm, 4.5mm, 5mm, 5.6mm, 6mm, 6.8mm, 7mm, 8mm, 9mm, 10mm, 11mm and 11.1mm.

[0095] In one embodiment, along the axial direction X, the area of ​​the projected region of the protrusion 32 is defined as S1, and the area of ​​the electrode assembly 20 is defined as S2, where 0.04 ≤ S1 / S2 ≤ 0.3. When the electrode assembly 20 shifts, the ratio of the projected area S1 of the protrusion 32 to the projected area S2 of the electrode assembly satisfies this range, which is beneficial to improving the limiting effect of the protrusion 32 on the electrode assembly 20, reducing the impact of the width of the protrusion 32 on the space utilization rate within the receiving cavity 13, reducing the impact of the width of the protrusion 32 on the energy density of the cylindrical battery 100, and reducing the risk of the first insulating member 42 coming into contact with the recess 111 and being squeezed by the recess 111, thereby extending the service life of the first insulating member 42.

[0096] The projection area of ​​the protrusion 32 along the axial direction X refers to the projection of the end face of the protrusion 32 along the axial direction X, that is, the projection area of ​​the end face with a width of L1 in the radial direction.

[0097] In one embodiment, 0.06≤S1 / S2≤0.3 is beneficial to further improve the limiting effect of the protrusion 32 on the electrode assembly 20, and also takes into account the influence of the width of the protrusion 32 on the space utilization rate within the receiving cavity 13.

[0098] In one embodiment, 0.18≤S1 / S2≤0.24 is beneficial to further improve the limiting effect of the protrusion 32 on the electrode assembly 20 and reduce the impact of the width of the protrusion 32 on the space utilization rate of the receiving cavity 13.

[0099] In one embodiment, the value of S1 / S2 is any one of 0.04, 0.06, 0.08, 0.1, 0.12, 0.14, 0.16, 0.18, 0.2, 0.22, 0.24, 0.26, 0.28 and 0.3, which is beneficial to both improve the limiting effect of the protrusion 32 on the electrode assembly 20 and reduce the impact of the width of the protrusion 32 on the space utilization rate within the receiving cavity 13.

[0100] In one embodiment, the projection area of ​​the protrusion 32 along the axial direction X is annular. The inner radius r1 and outer radius r2 of the annular projection can be calculated using a Keyence IM 8000 tester to calculate the projection area S1 of the protrusion 32, where S1 = π*(r2)^2 - π*(r1)^2, and π is taken as 3.14.

[0101] In one embodiment, the radius of the outer contour of the electrode assembly 20 can be obtained by taking 20 points evenly around the outer contour of the electrode assembly 20 using a Keyence IM 8000 tester, fitting the center of a circle by taking points, calculating the distance from the 20 points to the center of the circle, taking the average value to obtain the radius of the electrode assembly 20, and calculating the cross-sectional area S2 of the electrode assembly 20, where Π is taken as 3.14.

[0102] In one embodiment, along the axial direction X, the area of ​​the projected region of the base 31 is defined as S3, where 0.06 ≤ S1 / S3 ≤ 0.45. When the electrode assembly 20 shifts, the ratio of the projected area S1 of the protrusion 32 to the projected area S3 of the base 31 satisfies this range, which is beneficial to improving the limiting effect of the protrusion 32 on the electrode assembly 20, reducing the impact of the width of the protrusion 32 on the space utilization rate within the receiving cavity 13, reducing the impact of the width of the protrusion 32 on the energy density of the cylindrical battery 100, and reducing the risk of the first insulating member 42 coming into contact with the recess 111 and being squeezed by the recess 111, thereby extending the service life of the first insulating member 42.

[0103] In one embodiment, the projected region of the base 31 along the axial direction X is annular, and the radial width of this annular region is L2. The projected area of ​​the base 31 along the axial direction X is the projected area of ​​the annular region with width L2 formed by the base 31. In one embodiment, the inner radius r3 and outer radius r4 of the projected annular region can be calculated using a Keyence IM 8000 tester to calculate the projected area S3 of the base 31, where S3 = π*(r4)^2 - π*(r3)^2, and π is taken as 3.14.

[0104] In one embodiment, 0.09≤S1 / S3≤0.36 is beneficial to both improve the limiting effect of the protrusion 32 on the electrode assembly 20 and reduce the impact of the width of the protrusion 32 on the space utilization rate of the receiving cavity 13.

[0105] In one embodiment, the ratio of the projected area S1 of the protrusion 32 to the projected area S3 of the base 31 is any one of 0.06, 0.09, 0.15, 0.2, 0.25, 0.26, 0.27, 0.3, 0.35, 0.36, 0.4, 0.44 and 0.45, which is beneficial to both improve the limiting effect of the protrusion 32 on the electrode assembly 20 and reduce the impact of the width of the protrusion 32 on the space utilization rate within the receiving cavity 13.

[0106] In one embodiment, the diameter of the cylindrical battery 100 is defined as D, where 30mm≤D≤100mm. This is beneficial for increasing the capacity of the cylindrical battery 100. At the same time, the protrusion 32 on the end cap 30 helps to suppress the movement of the electrode assembly 20 in the large-size cylindrical battery 100 and extend the service life of the cylindrical battery 100.

[0107] In one embodiment, the diameter D of the cylindrical battery 100 is any one of 30mm, 35mm, 40mm, 45mm, 50mm, 55mm, 60mm, 65mm, 70mm, 75mm, 80mm, 85mm, 90mm, 95mm and 100mm, which is beneficial to increase the capacity of the cylindrical battery 100. At the same time, the protrusion 32 on the end cap 30 is beneficial to suppress the movement of the electrode assembly 20 and extend the service life of the cylindrical battery 100.

[0108] As shown in Figures 2 to 4, in one embodiment, the cylindrical battery 100 further includes a current collector 50, which is disposed in the receiving cavity 13. The current collector 50 is located on the side of the electrode assembly 20 away from the bottom wall 12 and between the electrode assembly 20 and the end cap 30. The current collector 50 connects the electrode assembly 20 and the end cap 30. By providing the current collector 50 to connect the electrode assembly 20 and the end cap 30, it is convenient to realize the electrical connection between the end cap 30 and the electrode assembly 20, which helps to simplify the assembly process of the cylindrical battery 100 and improve the assembly efficiency of the cylindrical battery 100.

[0109] In one embodiment, the electrode assembly 20 includes a first electrode 21, a second electrode 22, and a diaphragm 23, with the diaphragm 23 disposed between the first electrode 21 and the second electrode 22. The first electrode 21, the diaphragm 23, and the second electrode 22 are wound together. One of the first electrode 21 and the second electrode 22 is a positive electrode, and the other is a negative electrode.

[0110] In one embodiment, the first electrode 21 is electrically connected to the current collector 50, and the second electrode 22 is electrically connected to the bottom wall 12.

[0111] In one embodiment, a portion of the separator 23 extends beyond the second electrode 22 in a direction opposite to the axial direction X, and a portion of the first electrode 21 extends beyond the separator 23. The portion of the first electrode 21 extending beyond the separator 23 is flattened to form a first flattened portion 211, which connects to the current collector 50. By providing the first flattened portion 211 to connect to the current collector 50, the connection process between the first electrode 21 and the current collector 50 is simplified, improving the assembly efficiency of the cylindrical battery 100 and enhancing the connection stability between the first electrode 21 and the current collector 50. In one embodiment, the first flattened portion 211 and the current collector 50 are welded together.

[0112] In one embodiment, the cylindrical battery 100 further includes an explosion-proof sheet 60, which is disposed in the receiving cavity 13. The explosion-proof sheet 60 is located on the side of the current collector 50 away from the electrode assembly 20. The explosion-proof sheet 60 connects the current collector 50 and the end cap 30. When the gas pressure in the receiving cavity 13 exceeds the upper limit that the explosion-proof sheet 60 can withstand, the gas in the receiving cavity 13 can break through the explosion-proof sheet 60, thereby achieving the purpose of pressure relief. This helps to reduce the risk of the cylindrical battery 100 exploding due to excessive internal gas pressure and improves the safety performance of the cylindrical battery 100.

[0113] In one embodiment, the explosion-proof sheet 60 is provided with a groove 61 recessed along the axial direction X. The groove 61 reduces the local thickness of the explosion-proof sheet 60, thereby forming a weak area. This weak area can be damaged when the gas pressure in the receiving cavity 13 is too high, thereby forming a pressure relief channel.

[0114] In one embodiment, along the axial direction X, a portion of the explosion-proof piece 60 is located between the end cap 30 and the second portion 422, connecting the end cap 30 and the second portion 422. The end cap 30 and the first insulating member 42 clamp and limit a portion of the structure of the explosion-proof piece 60, which helps to improve the shock resistance and drop resistance of the cylindrical battery 100, as well as reduce the number of parts limiting the explosion-proof piece 60 within the cylindrical battery 100, thereby improving the space utilization and energy density of the cylindrical battery 100.

[0115] In one embodiment, the radially upward end of the explosion-proof sheet 60 is a bent structure 62, which wraps around the edge of the base 31, thereby improving the connection stability between the explosion-proof sheet 60 and the end cap 30, and further enhancing the shock resistance and drop resistance of the cylindrical battery 100. In one embodiment, at least a portion of the bent structure 62 is located between the first portion 421 and the base 31, and the bent structure 62 connects the first portion 421 and the base 31.

[0116] In one embodiment, the cylindrical battery 100 further includes a first structural member 71, which is disposed between the explosion-proof sheet 60 and the current collector 50 and connects the explosion-proof sheet 60 and the current collector 50, so that the current collector 50 and the explosion-proof sheet 60 are electrically connected.

[0117] In one embodiment, the first structural member 71 is provided with a through hole 711, which can serve as a channel for the flow of gas or electrolyte, so that the gas or liquid in the receiving cavity 13 can act on the explosion-proof sheet 60 through the through hole 711, thereby reducing the risk of the cylindrical battery 100 exploding due to excessive internal gas pressure.

[0118] In one embodiment, along the axial direction X, a portion of the separator 23 extends beyond the first electrode 21, and a portion of the second electrode 22 extends beyond the separator 23. The portion of the second electrode 22 extending beyond the separator 23 is flattened to form a second flattened portion 221, which connects to the bottom wall 12. By providing the second flattened portion 221 to connect to the bottom wall 12, the connection process between the second electrode 22 and the bottom wall 12 is simplified, improving the assembly efficiency of the cylindrical battery 100 and enhancing the connection stability between the second electrode 22 and the bottom wall 12. In one embodiment, the second flattened portion 221 and the bottom wall 12 are welded together.

[0119] In one embodiment, the cylindrical battery 100 further includes a second structural member 72, which is disposed between the bottom wall 12 and the second flattened portion 221 and connects the bottom wall 12 and the second flattened portion 221. By providing the second structural member 72 to connect the bottom wall 12 and the second flattened portion 221, it is beneficial to simplify the connection process between the second electrode 22 and the bottom wall 12 and improve the assembly efficiency of the cylindrical battery 100.

[0120] In one embodiment, the second structural member 72 and the bottom wall 12 are welded together, which helps to improve the connection stability between the second structural member 72 and the bottom wall 12.

[0121] In one embodiment, the second structural member 72 and the second flattened portion 221 are welded together, which helps to improve the connection stability between the second structural member 72 and the second electrode 22.

[0122] To verify the shock resistance and drop resistance of the cylindrical battery in this application, multiple sets of embodiment and comparative tests were conducted, as follows:

[0123] In each embodiment, there are 12 cylindrical batteries. Each cylindrical battery 100 has a protrusion 32 on its end cap. The dimensions of the protrusion 32 are shown in Table 1.

[0124] Each comparative example contains 12 cylindrical batteries, and none of the cylindrical batteries have a protrusion 32.

[0125] Each of the aforementioned examples and comparative examples was subjected to roller tests. After all examples and comparative examples had been tested, the number of those that passed the test and the number that failed the test in each group were counted, as shown in Table 1.

[0126] The roller test method involves subjecting the cylindrical battery to an octahedral roller test. The octahedral roller is custom-made, with the following dimensions: inscribed circle diameter of 230mm, length of 230mm, and wall thickness of 10mm. The test speed is 66 rpm, and the test duration is 100 minutes. The resistance and voltage of the cylindrical battery before and after the test are compared.

[0127] The criteria for passing the drum test are: the change in battery terminal voltage before and after the test is within 100mV, and the change in battery resistance is within 20%. The criteria for failing the test are: the change in battery terminal voltage before and after the test is greater than 100mV, and the change in battery resistance is greater than 20%.

[0128] The battery terminal voltage can be tested using a battery tester (model: Neware CT-4016-5V-100A), and the battery resistance can be tested using an internal resistance tester (model: HIOKI BT3563).

[0129] Table 1

[0130] As shown in Table 1, the cylindrical battery 100 of the embodiment in this application has good drop resistance and shock resistance.

[0131] In summary, in the cylindrical battery 100 of this application, the end cap 30 is provided with a protrusion 32 extending toward the electrode assembly 20, and along the axial direction X, at least a portion of the structure of the second part 422 of the first insulating member 42 is located between the protrusion 32 and the electrode assembly 20. When the electrode assembly 20 moves, the protrusion 32 can press against the electrode assembly 20 through the first insulating member 42, which is beneficial to improve the shock resistance and drop resistance of the cylindrical battery 100 and extend the service life of the cylindrical battery 100.

[0132] As shown in FIG7, an embodiment of this application also provides a battery pack 200, including the cylindrical battery 100 of any of the foregoing embodiments.

[0133] In the battery pack 200 described above, the end cap 30 is provided with a protrusion 32 extending toward the electrode assembly 20, and along the axial direction X, at least a portion of the structure of the second part 422 of the first insulating member 42 is located between the protrusion 32 and the electrode assembly 20. When the electrode assembly 20 moves, the protrusion 32 can press against the electrode assembly 20 through the first insulating member 42, which is beneficial to improving the shock resistance and drop resistance of the cylindrical battery 100, thereby improving the shock resistance and drop resistance of the battery pack 200.

[0134] As shown in Figure 8, an embodiment of this application also provides an electrical device 300, including the cylindrical battery 100 of any of the foregoing embodiments, or the battery pack 200 of the foregoing.

[0135] Among the aforementioned electrical equipment 300, the cylindrical battery 100 or battery pack 200 has good shock resistance and drop resistance, which helps to improve the compatibility of the electrical equipment 300 with different application scenarios.

[0136] In one embodiment, the electrical equipment 300 includes, but is not limited to, electric vehicles, drones, electric two-wheelers, home appliances, consumer electronics, and power tools.

[0137] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any changes or substitutions within the technical scope disclosed in this application should be covered within the scope of this application.

Claims

1. A cylindrical battery, characterized in that, include: The shell has a receiving cavity; Electrode assembly is disposed in the receiving cavity; An end cap connects the housing and the electrode assembly. The end cap and the electrode assembly are arranged along the axial direction of the cylindrical battery. The end cap has a protrusion that extends toward the electrode assembly. The first insulating element includes a first portion and a second portion that are interconnected, the first portion connecting the end cap and the housing along the axial direction, and at least a portion of the second portion being located between the protrusion and the electrode assembly and connecting the protrusion and the electrode assembly.

2. The cylindrical battery as described in claim 1, characterized in that, The housing includes a sidewall, at least a portion of the first part is located between the end cap and the sidewall, and connects the end cap and the sidewall; The sidewall includes a recess that is recessed toward the axis of the cylindrical battery and is insulated from the electrode assembly. Along the axial direction, the projection of the recess and the projection of the electrode assembly overlap.

3. The cylindrical battery as described in claim 2, characterized in that, Along the axial direction, the projection of the concave portion surrounds the projection of the convex portion, and the projection of the concave portion is separate from the projection of the convex portion; and / or, Along the axial direction, the projection of the recess surrounds the projection of the second portion, and the projection of the recess is separate from the projection of the second portion.

4. The cylindrical battery as described in claim 2 or 3, characterized in that, Along the axial direction, the second portion does not extend beyond the recess.

5. The cylindrical battery as described in claim 2 or 3, characterized in that, Along the axial direction, the end of the recess extends beyond the end face of the second portion.

6. The cylindrical battery according to any one of claims 2 to 5, characterized in that, The end cap includes a base, a portion of which protrudes along the axial direction to form the convex portion, the base including a first plane facing the electrode assembly, and the convex portion extending beyond the first plane along the axial direction; Along the axial direction, the length of the protrusion extending beyond the first plane is defined as T, where 1mm ≤ T ≤ 1.3mm.

7. The cylindrical battery as described in claim 6, characterized in that, The end cap further includes a connecting portion that connects to the base and extends in a direction opposite to the axial direction; The base includes a first region and a second region, the protrusion connects the first region and the second region, the first region is connected to the connecting portion, and the second region is connected to the first portion; Along the axial direction, the first region is closer to the electrode assembly than the second region.

8. The cylindrical battery according to any one of claims 2 to 7, characterized in that, Along the axial direction, the projection of the protrusion lies within the projection of the second portion.

9. The cylindrical battery according to any one of claims 2 to 8, characterized in that, Along the axial direction, the area of ​​the projected region of the protrusion is defined as S1, and the area of ​​the electrode assembly is defined as S2, where 0.04≤S1 / S2≤0.

3.

10. The cylindrical battery as described in claim 9, characterized in that, 0.06≤S1 / S2≤0.

3.

11. The cylindrical battery as described in claim 10, characterized in that, 0.18≤S1 / S2≤0.

24.

12. The cylindrical battery according to any one of claims 2 to 11, characterized in that, Along the radial direction of the cylindrical battery, the width of the protrusion is defined as L1, where 0.7mm ≤ L1 ≤ 11.1mm.

13. The cylindrical battery according to any one of claims 2 to 12, characterized in that, The end cap includes a base, a portion of which protrudes along the axial direction to form the protrusion; Along the axial direction, the area of ​​the projected region of the protrusion is defined as S1, and the area of ​​the projected region of the base is defined as S3, where 0.06≤S1 / S3≤0.

45.

14. The cylindrical battery as described in claim 13, characterized in that, 0.09≤S1 / S3≤0.

36.

15. The cylindrical battery according to any one of claims 2 to 14, characterized in that, The cylindrical battery further includes a second insulating member, which is disposed in the receiving cavity; Along the axial direction, a portion of the second insulating member is located between the recess and the electrode assembly, and connects the recess and the electrode assembly; Along the axial direction, at least a portion of the second portion is located between the protrusion and the second insulating member, and connects the protrusion and the second insulating member.

16. The cylindrical battery as described in claim 15, characterized in that, Along the axial direction, the projection of the second portion lies within the projection of the second insulating element.

17. The cylindrical battery according to any one of claims 1 to 16, characterized in that, The cylindrical battery also includes: A collector plate is disposed in the receiving cavity and located between the electrode assembly and the end cap; the collector plate is connected to the electrode assembly. An explosion-proof plate is disposed in the receiving cavity and located on the side of the collector plate away from the electrode assembly. The explosion-proof plate connects the collector plate and the end cap. A portion of the explosion-proof plate is located between the end cap and the second portion and connects the end cap and the second portion.

18. The cylindrical battery according to any one of claims 1 to 17, characterized in that, The diameter of the cylindrical battery ranges from 30 to 100 mm.

19. A battery pack, characterized in that, Including the cylindrical battery as described in any one of claims 1 to 18.

20. An electrical appliance, characterized in that, Includes a cylindrical battery as described in any one of claims 1 to 18, or a battery pack as described in claim 19.

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