Cylindrical battery cell, battery apparatus, and electrical apparatus

Abstract

A cylindrical battery cell (20), a battery apparatus (100), and an electrical apparatus, belonging to the technical field of batteries. The cylindrical battery cell (20) comprises a casing (21), an electrode assembly (22), and a first current collecting component (23). The electrode assembly (22) is provided within the casing (21), and the electrode assembly (22) has a first tab (222). The first tab (222) is electrically connected to a wall portion (211) of the casing (21) by means of the first current collecting component (23). The wall portion (211) comprises a main body region (2111) and a first connection region (2112) that are connected to one another. The first current collecting component (23) comprises a main body region (231) and a second connection region (232). The main body region (231) is connected to the first tab (222). The second connection region (232) is welded and connected to the wall portion (211), forming a connection portion (24). Part of the connection portion (24) is embedded within the first connection region (2112), and the connection portion (24) is connected to the main body region (2111) by means of the first connection region (2112). The hardness of the first connection region (2112) is less than the hardness of the main body region (2111), such that the first connection region (2112) can provide a certain buffering effect between the connection portion (24) and the main body region (2111), thereby alleviating the rigid pulling between the first current collecting component (23) and the wall portion (211), and reducing the phenomenon of welding failure between the first current collecting component (23) and the wall portion (211).

Description

Cylindrical battery cells, battery packs and electrical devices Technical Field

[0001] This application relates to the field of battery technology, and more specifically, to a cylindrical battery cell, a battery device, and an electrical device. Background Technology

[0002] In recent years, new energy vehicles have experienced rapid development. In the field of electric vehicles, power batteries, as the power source of electric vehicles, play an irreplaceable and important role. With the vigorous promotion of new energy vehicles, the demand for power battery products is also increasing. Among them, battery devices typically include a casing and multiple cylindrical battery cells housed within the casing.

[0003] In battery technology, a cylindrical battery cell includes a casing and an electrode assembly housed within the casing. The electrode assembly has tabs that are welded to a current collector, which in turn is welded to the casing. This allows the cylindrical battery cell to input or output electrical energy through the casing. However, in the prior art, cylindrical battery cells are prone to detachment of the current collector from the casing or the tabs during use, which can lead to connection failure between the electrode assembly and the casing. This is detrimental to improving the stability and lifespan of the cylindrical battery cell.

[0004] Summary of the Invention

[0005] This application provides a cylindrical battery cell, a battery device, and an electrical device, which can effectively improve the stability and service life of the cylindrical battery cell.

[0006] In a first aspect, embodiments of this application provide a cylindrical battery cell, including a casing, an electrode assembly, and a first current collector; the casing has a wall portion; the electrode assembly is disposed within the casing, and the electrode assembly has a first tab; the first current collector is located within the casing, and the first tab is electrically connected to the wall portion through the first current collector; wherein, the wall portion includes a main body region and a first connecting region connected to each other, the first current collector includes a body region and a second connecting region, the body region is connected to the first tab, the second connecting region is welded to the wall portion to form a connecting portion, a portion of the connecting portion is embedded in the first connecting region, and the connecting portion is connected to the main body region through the first connecting region, and the hardness of the first connecting region is less than the hardness of the main body region.

[0007] In the above technical solution, a first current collector is provided inside the casing. The body area of ​​the first current collector is connected to the first tab of the electrode assembly, and the second connection area of ​​the first current collector is welded to the wall of the casing to enable the cylindrical battery cell to input or output electrical energy through the wall. The wall of the casing forms a main body area and a first connection area that are interconnected. By setting the hardness of the first connection area to be less than that of the main body area, and by partially embedding the connection portion formed by welding the second connection area of ​​the first current collector to the wall of the casing within the first connection area, the connection portion is a structure that connects to the main body area through the first connection area. That is, the second connection area of ​​the first current collector is connected to the first connection area. The structure, which involves welding the components together to form a connecting part, connects the connecting part to the main body area via a first connecting area. When the second connecting area of ​​the first current collector pulls on the wall due to the shaking of the electrode assembly during use, the first connecting area can act as a buffer between the connecting part and the main body area. This can alleviate the rigid tension between the second connecting area and the wall of the first current collector, reducing the likelihood of weld detachment. Consequently, it can lower the risk of connection failure between the electrode assembly and the wall of the casing during the use of the cylindrical battery cell, thereby improving the stability and service life of the cylindrical battery cell.

[0008] In some embodiments, the first connection area includes two first sub-connection areas, which are located on opposite sides of the connection portion in the width direction of the connection portion.

[0009] In the above technical solution, the first connection area has two first sub-connection areas located on both sides of the connection part in the width direction of the connection part, so that each side of the connection part is connected to the main body area through a first sub-connection area. This allows the first connection area to play a certain buffering role on both sides of the connection part, which helps to further alleviate the rigid tension between the first current collector and the wall, thereby further reducing the phenomenon of weld detachment between the first current collector and the wall, and further reducing the risk of connection failure between the electrode assembly and the wall of the outer shell.

[0010] In some embodiments, the second connection area is stacked with the first connection area, and the connection portion connects the second connection area and the first connection area; wherein, the first connection area has a first surface facing the second connection area, and the minimum distance between the orthographic projection of the portion of the connection portion embedded in the first connection area and the outer edge of the first surface is L1, satisfying 0.05mm≤L1≤2.5mm.

[0011] In the above technical solution, the minimum distance between the orthographic projection of the portion of the connecting part embedded in the first connecting area on the first surface and the outer edge of the first surface is 0.05mm to 2.5mm, so that the minimum size of the first connecting area between the connecting part and the main body area is 0.05mm to 2.5mm. On the one hand, by setting the minimum distance between the orthographic projection of the portion of the connecting part embedded in the first connecting area on the first surface and the outer edge of the first surface to be greater than or equal to 0.05mm, the size of the buffer area between the connecting part and the main body area can be increased, which is beneficial to improving the buffering effect of the first connecting area between the connecting part and the main body area. This can further alleviate the rigid tension between the second connecting area and the wall of the first current collector, so as to further reduce the phenomenon of weld detachment between the second connecting area and the wall of the first current collector. On the other hand, by setting the minimum distance between the orthographic projection of the portion of the connecting part embedded in the first connecting area on the first surface and the outer edge of the first surface to be less than or equal to 2.5mm, the phenomenon of weakening the overall structural strength of the wall due to excessive space occupied by the first connecting area can be alleviated. Thus, while realizing the buffering effect of the first connecting area between the connecting part and the main body area, the overall structural strength of the shell can also be improved.

[0012] In some embodiments, the Vickers hardness value of the first connection region is greater than or equal to 50 and less than or equal to 180.

[0013] In the above technical solution, the Vickers hardness of the first connection area is 50 to 180. On the one hand, by setting the Vickers hardness of the first connection area to be greater than or equal to 50, the structural strength of the first connection area is improved, which helps to alleviate the phenomenon of cracking or damage that occurs during the assembly of the first connection area and the first current collector or during use, thereby improving the stability of the cylindrical battery cell. On the other hand, by setting the Vickers hardness of the first connection area to be less than or equal to 180, the buffering effect between the first connection area and the main body area is improved, which further alleviates the rigid tension between the second connection area and the wall of the first current collector, thereby further reducing the phenomenon of weld detachment between the second connection area and the wall of the first current collector.

[0014] In some embodiments, the Vickers hardness value of the main body region is greater than or equal to 70 and less than or equal to 200.

[0015] In the above technical solution, the Vickers hardness of the main body area is 70 to 200. On the one hand, by setting the Vickers hardness of the main body area to be greater than or equal to 70, the overall structural strength of the wall is improved, which helps to alleviate the phenomenon of cracking or damage to the wall during use, thereby improving the stability of the cylindrical battery cell. On the other hand, by setting the Vickers hardness of the main body area to be less than or equal to 200, the molding and processing difficulty of the wall is reduced, and the manufacturing cost of the cylindrical battery cell is reduced.

[0016] In some embodiments, the axial direction of the cylindrical battery cell is a first direction, and the housing includes a shell and an end cap; the shell includes an integrally formed side wall and a bottom wall, the side wall surrounds the bottom wall, one end of the side wall is connected to the bottom wall along the first direction, and the other end forms an opening, the side wall and the bottom wall together define a receiving cavity, and the electrode assembly is received in the receiving cavity; the end cap closes the opening; wherein, the wall portion is the side wall or the bottom wall.

[0017] In the above technical solution, by setting the side wall or bottom wall of the housing as a wall, the second connection area of ​​the first current collector is a structure that is welded to the side wall or bottom wall of the housing. This can alleviate the stress generated by the first current collector pulling or torsion on the wall and acting on the end cover, thereby reducing the risk of connection failure between the end cover and the housing, and thus effectively improving the stability of the cylindrical battery cell.

[0018] In some embodiments, the wall portion is the sidewall; wherein, a first protrusion is formed on the side of the sidewall facing the receiving cavity, the end cap is located on the side of the first protrusion facing the opening along the first direction, at least a portion of the electrode assembly is located on the side of the first protrusion facing away from the opening, and the body region is located at the end of the electrode assembly facing the end cap, the second connection region is welded to the first protrusion to form the connection portion, a portion of the first protrusion forms the first connection region, and another portion of the first protrusion forms a part of the body region.

[0019] In the above technical solution, the sidewall of the shell is a wall portion, and a first protrusion is formed on the side of the sidewall facing the receiving cavity. The end cap is located on the side of the first protrusion facing the opening. At least a portion of the electrode assembly is located on the side of the first protrusion away from the opening. By setting the second connection area of ​​the first current collector to be welded to the first protrusion of the sidewall to form a connection portion, the first connection area is formed on the first protrusion. The cylindrical battery cell with this structure can, on the one hand, limit or position the electrode assembly and the end cap to a certain extent through the first protrusion, which is beneficial to reduce the assembly difficulty of the cylindrical battery cell. On the other hand, it can effectively reduce the difficulty of welding the second connection area of ​​the first current collector to the sidewall, thereby reducing the assembly difficulty of the second connection area of ​​the first current collector to the wall portion.

[0020] In some embodiments, the first protrusion is an annular structure extending circumferentially along the sidewall.

[0021] In the above technical solution, by setting the first protrusion as a ring structure extending circumferentially along the sidewall, on the one hand, the limiting or positioning effect of the first protrusion on the electrode assembly and end cap can be further improved; on the other hand, it can be realized that the first protrusion can be welded to the second connection area of ​​the first current collector at any position in the circumferential direction of the sidewall, so that the second connection area of ​​the first current collector and the first protrusion can be welded to each other. This means that after the first current collector is assembled into the housing, the welding assembly of the second connection area and the first protrusion can be achieved without rotating and adjusting the position of the first current collector. This helps to further reduce the welding difficulty between the second connection area of ​​the first current collector and the first protrusion, thereby effectively improving the assembly efficiency of the cylindrical battery cell.

[0022] In some embodiments, the first protrusion forms a plurality of first connection areas, the plurality of first connection areas are arranged at circumferential intervals along the sidewall, and each first connection area is connected to a corresponding connection portion.

[0023] In the above technical solution, a plurality of first connection areas are formed on the first protrusion at circumferential intervals along the sidewall, and each first connection area is connected to a corresponding connection part, so that the first current collector and the first protrusion are welded together to form a plurality of connection parts at circumferential intervals along the sidewall, and each connection part is connected to the main body area through a first connection area. This can further improve the connection stability and reliability between the first current collector and the wall, which is conducive to further alleviating the phenomenon of weld detachment between the first current collector and the wall. On the other hand, it can increase the flow area between the first current collector and the wall to improve the flow capacity between the first current collector and the wall.

[0024] In some embodiments, the sidewall is formed on the side opposite to the receiving cavity and at a position corresponding to the first protrusion, forming a first groove.

[0025] In the above technical solution, by forming a first groove on the side of the sidewall facing away from the receiving cavity and corresponding to the position of the first protrusion, the first protrusion formed on the side of the sidewall facing the receiving cavity can be a structure that can be formed by stamping. This allows the first protrusion to be formed on the side of the sidewall facing the receiving cavity, and the first groove to be formed on the other side and corresponding to the position of the first protrusion. Cylindrical battery cells with this structure can reduce the difficulty of forming the first protrusion on the side of the sidewall facing the receiving cavity, which is beneficial to improving the production efficiency of cylindrical battery cells. On the other hand, it can realize that the interior of the first protrusion is a hollow structure, which can reduce the power required for welding the first protrusion and the second connection area of ​​the first current collector to each other, which is beneficial to reducing the welding difficulty between the first protrusion and the second connection area of ​​the first current collector. Furthermore, it allows the first protrusion to have the ability of elastic deformation, which is beneficial to further alleviate the rigid tension between the second connection area of ​​the first current collector and the first protrusion, thereby reducing the risk of weld detachment between the second connection area of ​​the first current collector and the first protrusion.

[0026] In some embodiments, the wall thickness of the first protrusion is less than the wall thickness of the other portions of the first protrusion.

[0027] In the above technical solution, by setting the wall thickness of the first protrusion portion to be less than the wall thickness of the other portions of the first protrusion, the first protrusion is locally thinned and forms a thinned area, thereby improving the elastic deformation capability of the first protrusion. This helps to further alleviate the rigid tension between the second connection area of ​​the first current collector and the first protrusion, thereby reducing the risk of weld detachment between the second connection area of ​​the first current collector and the first protrusion.

[0028] In some embodiments, the thickness of the first connection region is less than the wall thickness of the region of the sidewall where the first protrusion is not formed.

[0029] In the above technical solution, by setting the thickness of the first connection area to be less than the wall thickness of the area of ​​the side wall where the first protrusion is not formed, the structural strength of the side wall can be improved, and the buffering effect of the first connection area between the connection part and the main body area can be further improved, so as to further alleviate the rigid tension between the second connection area and the wall of the first current collector, which is conducive to further reducing the phenomenon of weld detachment between the second connection area and the wall of the first current collector.

[0030] In some embodiments, along the first direction, the second connection area is located on the side of the first protrusion facing the end cap, and the second connection area is welded to the side of the first protrusion facing the end cap to form the connection portion.

[0031] In the above technical solution, the electrode assembly is located on the side of the first protrusion away from the end cover in the first direction. The first current collector is connected to the first tab of the electrode assembly, and the second connection area of ​​the first current collector is located on the side of the first protrusion facing the end cover in the first direction and is welded to the side of the first protrusion facing the end cover. The cylindrical battery cell with this structure can, on the one hand, realize that the first current collector and the first protrusion can share part of the space in the first direction, which is beneficial to improve the internal space utilization of the cylindrical battery cell and thus improve the energy density of the cylindrical battery cell. On the other hand, the second connection area of ​​the first current collector is located on the side of the first protrusion facing the opening of the shell in the first direction and is welded to the surface of the first protrusion facing the opening. This allows the first protrusion and the second connection area to be welded and assembled from the opening of the shell, which is beneficial to optimize the production process of the cylindrical battery cell and reduce the assembly difficulty of the cylindrical battery cell.

[0032] In some embodiments, along the first direction, the second connection area is located on the side of the first protrusion away from the end cap, and the second connection area is welded to the side of the first protrusion away from the end cap to form the connection portion.

[0033] In the above technical solution, by setting the second connection area of ​​the first current collector in the first direction to be located on the side of the first protrusion away from the end cover and welded to the side of the first protrusion away from the end cover, the second connection area of ​​the first current collector and the electrode assembly are both located on the side of the first protrusion away from the end cover, which helps to reduce the assembly difficulty of the first current collector and the electrode assembly. In addition, the first protrusion can also play a certain role in limiting and positioning the first current collector.

[0034] In some embodiments, the second connection region is located on the side of the body region facing the end cap in the first direction; wherein the first current collection member further includes a transition region connecting the body region and the second connection region, the transition region being configured to deform when the body region and the second connection region move closer or further apart from each other along the first direction.

[0035] In the above technical solution, the first current collector is also provided with a transition area connecting the body area and the second connection area. By setting the transition area as a structure that can deform when the body area and the second connection area move closer or further apart along the first direction, the transition area can play a certain buffering role between the body area and the second connection area. In the process of the electrode assembly shaking or shifting, it can alleviate the rigid tension between the body area and the second connection area, between the body area and the first electrode tab, and between the second connection area and the first protrusion. This is beneficial to further reduce the risk of connection failure between the body area and the first electrode tab and between the second connection area and the first protrusion, and also helps to reduce the phenomenon of the first current collector being damaged by tension.

[0036] In some embodiments, the transition region is bent to form a plurality of bent segments, which are connected sequentially, and the bent segments located at both ends of the plurality of bent segments are respectively connected to the body region and the second connection region.

[0037] In the above technical solution, by setting the transition area as a structure of multiple bent segments connected in sequence, and the bent segments at both ends of the multiple bent segments are respectively connected to the body area and the second connecting area, the deformation capacity of the transition area can be increased when the body area and the second connecting area move closer or further away from each other along the first direction, so as to further improve the buffering effect of the transition area between the body area and the second connecting area, and further reduce the phenomenon of rigid tension between the body area and the second connecting area, between the body area and the first tab, and between the second connecting area and the first protrusion.

[0038] In some embodiments, the end cap is provided with a pressure relief component, which is configured to release the internal pressure of the cylindrical battery cell.

[0039] In the above technical solution, by setting a pressure relief component on the end cap to release the internal pressure of the cylindrical battery cell, the cylindrical battery cell can still be depressurized through the pressure relief component when thermal runaway occurs, which helps to reduce the risk of explosion of the cylindrical battery cell during use and improve the reliability of the cylindrical battery cell.

[0040] In some embodiments, in a projection plane perpendicular to the first direction, the orthographic projection of the body region and the orthographic projection of the second connection region form an exhaust gap in the radial direction of the cylindrical battery cell.

[0041] In the above technical solution, in the projection plane perpendicular to the first direction, by setting the orthographic projection of the second connection area and the orthographic projection of the body area to form a structure with an exhaust gap in the radial direction of the cylindrical battery cell, the thermal runaway gas inside the cylindrical battery cell can enter the side of the first current collector facing the end cap through the exhaust gap between the second connection area and the body area and then be released through the pressure relief component. This helps to reduce the obstruction of the exhaust path inside the cylindrical battery cell by the first current collector, thereby improving the smoothness of the internal exhaust and the pressure relief rate of the cylindrical battery cell.

[0042] In some embodiments, the pressure relief component is provided with a pressure relief groove, at least a portion of the projection of the pressure relief groove in the first direction being located within the exhaust gap.

[0043] In the above technical solution, by setting the pressure relief groove on the pressure relief component to a structure in which at least part of the projection in the first direction is located within the exhaust gap, the pressure relief groove is a structure in which at least part of the projection in the first direction corresponds to the exhaust gap between the second connection area and the body area. This can further improve the smoothness of internal exhaust and pressure relief of the cylindrical battery cell, thereby increasing the pressure relief rate of the cylindrical battery cell and reducing the risk of fire and explosion caused by untimely pressure relief of the cylindrical battery cell, thus improving the reliability of the cylindrical battery cell.

[0044] In some embodiments, in a projection plane perpendicular to the first direction, the orthographic projection of the second connection area extends circumferentially along the cylindrical battery cell and is located on the periphery of the orthographic projection of the body area, and the orthographic projection of the second connection area and the orthographic projection of the body area are arranged radially spaced apart in the cylindrical battery cell, the diameter of the orthographic projection of the outer edge of the second connection area is D1, and the orthographic projection of the transition area extends radially along the cylindrical battery cell with a length of L2, satisfying 1 / 15≤L2 / D1≤1 / 3.

[0045] In the above technical solution, in the projection plane perpendicular to the first direction, by setting the orthographic projection of the second connection area and the orthographic projection of the body area to be arranged at intervals in the radial direction of the cylindrical battery cell, and setting the ratio of the length of the transition area of ​​the first current collector in the radial direction of the cylindrical battery cell to the diameter of the orthographic projection of the outer edge of the second connection area to 1 / 15 to 1 / 3, it can alleviate the phenomenon that the size occupied by the transition area in the radial direction of the cylindrical battery cell is too small, and is conducive to expanding the exhaust space between the second connection area and the body area, so that the thermal runaway gas inside the cylindrical battery cell can pass through the exhaust space between the second connection area and the body area and then through the end cap. The pressure relief component releases pressure, thereby improving the internal venting smoothness of the cylindrical battery cell and increasing the pressure relief rate of the cylindrical battery cell. This reduces the risk of the cylindrical battery cell bursting or exploding due to untimely pressure relief. On the other hand, it can alleviate the phenomenon that the transition zone occupies too large a size in the radial direction of the cylindrical battery cell, resulting in insufficient support strength between the body area and the second connection area. This can effectively improve the support effect of the first current collector on the electrode assembly and the effect of resisting the expansion of the electrode assembly during use, thereby alleviating the phenomenon of excessive expansion or displacement of the electrode assembly. This is conducive to improving the stability and reliability of the cylindrical battery cell in use.

[0046] In some embodiments, 1 / 7 ≤ L2 / D1 ≤ 1 / 4.

[0047] In the above technical solution, within the projection plane perpendicular to the first direction, by further setting the ratio of the length of the transition zone of the first current collector in the radial direction of the cylindrical battery cell to the diameter of the orthographic projection of the outer edge of the second connecting zone to 1 / 7 to 1 / 4, the problem of the transition zone occupying too small a size in the radial direction of the cylindrical battery cell can be further alleviated. This facilitates further expansion of the exhaust space between the second connecting zone and the body zone, allowing the thermal runaway gas inside the cylindrical battery cell to be released through the exhaust space between the second connecting zone and the body zone via the pressure relief component on the end cap, thereby further improving the internal thermal stability of the cylindrical battery cell. The smoothness of the exhaust flow is improved to further enhance the depressurization rate of the cylindrical battery cells, thereby reducing the risk of bursting or exploding due to untimely depressurization. On the other hand, it can further alleviate the phenomenon that the transition zone occupies too large a size in the radial direction of the cylindrical battery cell, resulting in insufficient support strength between the body area and the second connection area. This can further improve the support effect of the first current collector on the electrode assembly and the effect of resisting the expansion of the electrode assembly during use, thereby further alleviating the phenomenon of excessive expansion or displacement of the electrode assembly, and thus helping to further improve the stability and reliability of the cylindrical battery cells.

[0048] In some embodiments, 3mm ≤ L2 ≤ 15mm.

[0049] In the above technical solution, in the projection plane perpendicular to the first direction, by setting the length of the transition zone of the first current collector in the radial direction of the cylindrical battery cell to 3mm to 15mm, on the one hand, setting the length of the transition zone in the radial direction of the cylindrical battery cell to be greater than or equal to 3mm can increase the exhaust space between the second connection area and the body area, so that the thermal runaway gas inside the cylindrical battery cell can be released through the exhaust space between the second connection area and the body area and then through the pressure relief component on the end cap, which is beneficial to improving the internal exhaust smoothness of the cylindrical battery cell. On the other hand, setting the length of the transition zone in the radial direction of the cylindrical battery cell to be less than or equal to 15mm can alleviate the phenomenon that the transition zone is too long and therefore the support strength of the transition zone between the body area and the second connection area is insufficient. This is beneficial to improving the support effect of the first current collector on the electrode assembly and the effect of resisting the expansion of the electrode assembly during use, so as to further alleviate the phenomenon of excessive expansion or displacement of the electrode assembly.

[0050] In some embodiments, the thickness of the transition region is T1, and the width of the orthographic projection of the transition region in a projection plane perpendicular to the first direction, in a direction perpendicular to its extension direction, is W, satisfying 0.3mm. 2 ≤W×T1≤8mm 2 .

[0051] In the above technical solution, the product of W and T1 is set to 0.3mm. 2 up to 8mm 2 On the one hand, the product of W and T1 is set to be less than or equal to 8mm. 2 This design can alleviate the problem of excessive deformation difficulty in the transition zone caused by excessively large W and T1 values. It improves the ability of the transition zone to deform when the body region and the second connecting region move closer or further apart along the first direction. This allows the transition zone to act as a better buffer between the body region and the second connecting region, reducing rigid tension between the body region and the second connecting region, between the body region and the first tab, and between the second connecting region and the first protrusion during electrode assembly wobbling or displacement. Furthermore, the product of W and T1 is set to be greater than or equal to 0.3 mm. 2 It can improve the structural strength of the transition zone, which helps to alleviate the phenomenon of insufficient support strength of the transition zone between the body zone and the second connection zone, thereby improving the support effect of the first current collector on the electrode assembly and the effect of resisting the expansion of the electrode assembly during use. It can also improve the flow capacity of the transition zone, which helps to improve the flow guiding effect and flow guiding requirements of the first current collector.

[0052] In some embodiments, in a projection plane perpendicular to the first direction, the width of the orthographic projection of the transition zone in a direction perpendicular to its extension direction is W, satisfying 2mm≤W≤10mm.

[0053] In the above technical solution, by setting the width of the projection of the transition zone of the first current collector in the first direction to 2mm to 10mm, on the one hand, setting the width of the projection of the transition zone in the first direction to be greater than or equal to 2mm can improve the flow capacity of the transition zone, thereby improving the flow guiding effect of the first current collector and improving the structural strength of the transition zone. This helps to alleviate the phenomenon of insufficient support strength of the transition zone between the body area and the second connection area, thereby improving the support effect of the first current collector on the electrode assembly and the effect of resisting the expansion of the electrode assembly during use. On the other hand, setting the width of the projection of the transition zone in the first direction to be less than or equal to 10mm can effectively improve the ability of the transition zone to deform when the body area and the second connection area move closer or further apart along the first direction. This allows the transition zone to play a better buffering role between the body area and the second connection area, thereby reducing the rigid pulling phenomenon between the body area and the second connection area, between the body area and the first electrode tab, and between the second connection area and the first protrusion during the process of the electrode assembly shaking or shifting.

[0054] In some embodiments, 3mm ≤ W ≤ 5mm.

[0055] In the above technical solution, by further setting the width of the projection of the transition zone of the first current collector in the first direction to 3mm to 5mm, on the one hand, setting the width of the projection of the transition zone in the first direction to be greater than or equal to 3mm can further improve the flow capacity of the transition zone, thereby further improving the flow guiding effect of the first current collector and further improving the structural strength of the transition zone. This is beneficial to further alleviate the phenomenon of insufficient support strength of the transition zone between the body area and the second connection area, thereby further improving the support effect of the first current collector on the electrode assembly and the effect of resisting the expansion of the electrode assembly during use. On the other hand, setting the width of the projection of the transition zone in the first direction to be less than or equal to 5mm can further improve the ability of the transition zone to deform when the body area and the second connection area move closer or further away from each other along the first direction, thereby improving the buffering effect of the transition zone between the body area and the second connection area. This can further reduce the rigid pulling phenomenon between the body area and the second connection area, between the body area and the first electrode tab, and between the second connection area and the first protrusion during the process of the electrode assembly shaking or shifting.

[0056] In some embodiments, the thickness of the transition region is T1, which satisfies 0.15mm≤T1≤0.8mm.

[0057] In the above technical solution, by setting the thickness of the transition zone of the first current collector to 0.15mm to 0.8mm, on the one hand, setting the thickness of the transition zone to greater than or equal to 0.15mm can improve the current carrying capacity of the transition zone, thereby improving the current guiding effect of the first current collector and improving the structural strength of the transition zone. This helps to alleviate the phenomenon of insufficient support strength of the transition zone between the body region and the second connection region, thereby improving the support effect of the first current collector on the electrode assembly and the effect of resisting the expansion of the electrode assembly during use. On the other hand, setting the thickness of the transition zone to less than or equal to 0.8mm can effectively improve the ability of the transition zone to deform when the body region and the second connection region move closer or further apart along the first direction. This allows the transition zone to play a better buffering role between the body region and the second connection region. In the process of the electrode assembly shaking or shifting, it can reduce the rigid pulling phenomenon between the body region and the second connection region, between the body region and the first electrode tab, and between the second connection region and the first protrusion. It can also save the space occupied by the transition zone in the first direction, which is beneficial to improving the internal space utilization rate of the cylindrical battery cell.

[0058] In some embodiments, 0.3mm ≤ T1 ≤ 0.5mm.

[0059] In the above technical solution, by further setting the thickness of the transition zone of the first current collector to 0.3mm to 0.5mm, on the one hand, setting the thickness of the transition zone to greater than or equal to 0.3mm can further improve the current carrying capacity of the transition zone, thereby further improving the current guiding effect of the first current collector and further improving the structural strength of the transition zone. This helps to further alleviate the phenomenon of insufficient support strength of the transition zone between the body area and the second connection area, thereby further improving the support effect of the first current collector on the electrode assembly and the effect of resisting the expansion of the electrode assembly during use. On the other hand, setting the thickness of the transition zone to less than or equal to 0.5mm can further improve the ability of the transition zone to deform when the body area and the second connection area move closer or further away from each other along the first direction, thereby further improving the buffering effect of the transition zone between the body area and the second connection area. This can further reduce the rigid pulling phenomenon between the body area and the second connection area, between the body area and the first electrode tab, and between the second connection area and the first protrusion during the process of the electrode assembly shaking or shifting. It can also further save the space occupied by the transition zone in the first direction, which is conducive to further improving the internal space utilization rate of the cylindrical battery cell.

[0060] In some embodiments, the thickness of the transition region is less than the thickness of the body region; and / or, the thickness of the transition region is less than the thickness of the second connection region.

[0061] In the above technical solution, by setting the thickness of the transition zone to be less than the thickness of the main body zone, the manufacturing cost and difficulty of the first current collector component are reduced, while the ability of the transition zone to deform when the main body zone and the second connecting zone move closer or further apart along the first direction is improved. This allows the transition zone to play a better buffering role between the main body zone and the second connecting zone. Similarly, by setting the thickness of the transition zone to be less than the thickness of the second connecting zone, the manufacturing cost and difficulty of the first current collector component are reduced, while the ability of the transition zone to deform when the main body zone and the second connecting zone move closer or further apart along the first direction is improved. This allows the transition zone to play a better buffering role between the main body zone and the second connecting zone.

[0062] In some embodiments, the sidewall is bent at one end away from the bottom wall in the first direction to form a flange, the flange enclosing the opening; wherein, along the first direction, a portion of the end cap is located between the flange and the first protrusion, the flange and the first protrusion being configured to cooperate in clamping the end cap.

[0063] In the above technical solution, by bending the side wall away from the bottom wall in the first direction to form a flange, and setting the end cap part in the first direction between the first protrusion and the flange, the first protrusion and the flange can also play a role in assembling and fixing the end cap, so as to realize the assembly between the end cap and the shell. The cylindrical battery cell with this structure can reduce the assembly difficulty between the end cap and the shell, thereby improving the production efficiency of the cylindrical battery cell.

[0064] In some embodiments, the cylindrical battery cell further includes a seal; at least a portion of the seal is disposed radially between the sidewall and the end cap of the cylindrical battery cell, and the seal is configured to seal the end cap and the sidewall.

[0065] In the above technical solution, the cylindrical battery cell is also provided with a sealing element. By disposing at least a portion of the sealing element in the radial direction of the cylindrical battery cell between the side wall and the end cap, the sealing element can seal the gap between the end cap and the side wall, thereby reducing the risk of leakage during the use of the cylindrical battery cell and improving the stability and reliability of the cylindrical battery cell.

[0066] In some embodiments, the wall portion is the sidewall; wherein, the body region is located at one end of the electrode assembly in the first direction, and the body region is connected to the first tab, the second connection region extends circumferentially along the sidewall and surrounds the body region, the second connection region is welded to the sidewall to form the connection portion, a portion of the sidewall forms the first connection region, and another portion of the sidewall forms the main body region.

[0067] In the above technical solution, the sidewall of the housing is a wall portion. By setting the body area of ​​the first current collector component to be located at one end of the electrode assembly in the first direction and connecting the body area to the first electrode tab, and setting the second connection area to be a structure surrounding the body area along the circumference of the sidewall, the second connection area of ​​the first current collector component and the sidewall can be welded together. This helps to reduce the welding difficulty between the first current collector component and the sidewall, and can increase the area of ​​the first current collector component for welding with the sidewall, thereby improving the connection reliability between the first current collector component and the sidewall.

[0068] In some embodiments, along the first direction, one end of the second connection region is connected to the body region, and the second connection region extends from the body region toward the end cap.

[0069] In the above technical solution, by connecting one end of the second connection area to the body area in the first direction and setting the second connection area to extend from the body area toward the end cap, the second connection area is a side of the body area that protrudes in the first direction and faces the opening of the casing. The cylindrical battery cell with this structure is convenient for welding the second connection area and the side wall, which helps to reduce the welding assembly difficulty between the second connection area and the side wall. On the other hand, it can alleviate the phenomenon of the second connection area being inserted into the electrode assembly or squeezing the electrode assembly, which helps to reduce the risk of damage or wear of the electrode assembly during use.

[0070] In some embodiments, the axial direction of the cylindrical battery cell is a first direction, and the housing includes a shell and an end cap; the shell includes an integrally formed side wall and a bottom wall, the side wall surrounds the bottom wall, one end of the side wall is connected to the bottom wall along the first direction, and the other end forms an opening, the side wall and the bottom wall together define a receiving cavity, and the electrode assembly is received in the receiving cavity; the end cap closes the opening; wherein, the wall portion is the end cap.

[0071] In the above technical solution, by setting the end cap of the outer casing as a wall, the second connection area of ​​the first current collector is a structure that is welded to the end cap, thereby reducing the welding and assembly difficulty between the second connection area of ​​the first current collector and the wall, and improving the production efficiency of the cylindrical battery cell.

[0072] In some embodiments, along the first direction, a second protrusion is formed on the side of the end cap facing the electrode assembly, the second connection area is welded to the second protrusion to form the connection portion, a portion of the second protrusion forms the first connection area, and another portion of the second protrusion forms a part of the main body area.

[0073] In the above technical solution, by forming a second protrusion on the side of the end cap facing the electrode assembly, and the second connection area of ​​the first current collector is welded to the second protrusion of the end cap to form a connection part, the first connection area is formed on the second protrusion. The cylindrical battery cell with this structure can improve the contact effect between the area of ​​the end cap used for welding to the second connection area and the second connection area in the first direction, thereby improving the welding quality between the second connection area of ​​the first current collector and the end cap.

[0074] In some embodiments, the second protrusion is an annular structure extending circumferentially along the sidewall.

[0075] In the above technical solution, by setting the second protrusion as an annular structure extending circumferentially along the sidewall, the second protrusion can be welded to the second connection area of ​​the first current collector at any position in the circumferential direction of the sidewall. This facilitates the welding connection between the second connection area of ​​the first current collector and the second protrusion. After the first current collector is assembled into the housing, the welding assembly of the second connection area and the second protrusion can be achieved without rotating and adjusting the position of the first current collector. This effectively reduces the welding difficulty between the second connection area and the second protrusion of the first current collector, thereby improving the assembly efficiency of the cylindrical battery cell.

[0076] In some embodiments, along the first direction, the end cap has a second groove formed on the side opposite to the electrode assembly and corresponding to the position of the second protrusion.

[0077] In the above technical solution, by forming a second groove on the side of the end cap away from the electrode assembly and corresponding to the second protrusion, the second protrusion formed on the side of the end cap facing the electrode assembly can be formed by stamping. This allows the second protrusion to be formed on the side of the end cap facing the electrode assembly, and a second groove to be formed on the other side and corresponding to the second protrusion. Cylindrical battery cells with this structure can reduce the difficulty of forming the second protrusion on the side of the end cap facing the electrode assembly, which is beneficial to improving the production efficiency of cylindrical battery cells. On the other hand, it can realize that the interior of the second protrusion is a hollow structure, which can reduce the power required for welding the second protrusion and the second connection area of ​​the first current collector, which is beneficial to reducing the welding difficulty between the second protrusion and the second connection area of ​​the first current collector.

[0078] In some embodiments, the electrode assembly further includes a body portion, with the first electrode tab connected to one end of the body portion along the first direction, and the body region located on the side of the first electrode tab opposite to the body portion and connected to the first electrode tab.

[0079] In the above technical solution, by setting the first electrode tab to be connected to one end of the main body and setting the body area of ​​the first current collector on the side of the first electrode tab away from the main body, the main body, the first electrode tab and the body area are arranged in sequence along the first direction, thereby reducing the assembly difficulty between the first electrode tab and the body area of ​​the first current collector, which is conducive to improving the production efficiency of cylindrical battery cells and optimizing the production process of cylindrical battery cells.

[0080] In some embodiments, the material of the first current collector includes copper.

[0081] In some embodiments, the first electrode tab is welded to the body region.

[0082] In the above technical solution, by setting the body area of ​​the first electrode and the first current collector as a welded connection, it is beneficial to improve the connection reliability and robustness between the first electrode and the body area of ​​the first current collector, thereby improving the stability of the cylindrical battery cell in use. Furthermore, the hardness of the first connecting area of ​​the wall is less than that of the main body area of ​​the wall, and the connecting part formed by welding the second connecting area of ​​the first current collector to the wall of the outer casing is a structure connected to the first connecting area. That is, the second connecting area of ​​the first current collector is a structure formed by welding the first connecting area to the first connecting area, so that the connecting part is connected to the main body area through the first connecting area. This allows the first connecting area to play a certain buffering role between the connecting part and the main body area when the first electrode pulls the first current collector due to the shaking of the electrode assembly during the use of the cylindrical battery cell. This enables the first current collector to have the ability to float slightly relative to the wall, thereby alleviating the rigid pulling between the first electrode and the main body area of ​​the first current collector. This helps to reduce the phenomenon of weld detachment between the first electrode and the main body area of ​​the first current collector, and further reduces the risk of connection failure between the electrode assembly and the wall of the outer casing during the use of the cylindrical battery cell, thereby improving the stability and service life of the cylindrical battery cell.

[0083] In some embodiments, the wall thickness of the wall portion is T2, which satisfies 0.2mm≤T2≤0.8mm.

[0084] In the above technical solution, the wall thickness of the wall portion is 0.2mm to 0.8mm. On the one hand, by setting the wall thickness to be greater than or equal to 0.2mm, it is beneficial to improve the structural strength of the wall portion, thereby reducing the phenomenon of deformation or cracking during use. It can also reduce the risk of welding defects during the welding assembly of the wall portion and the second connection area of ​​the first current collector. On the other hand, by setting the wall thickness to be less than or equal to 0.8mm, it can alleviate the phenomenon of excessive weight of the cylindrical battery cell, and can save the amount of wall portion used, thereby reducing the phenomenon of excessive material waste. This is beneficial to reduce the manufacturing cost of the cylindrical battery cell. Furthermore, when welding the wall portion to the second connection area of ​​the first current collector, it can reduce the welding power required, thereby reducing the welding assembly difficulty between the first current collector and the wall portion.

[0085] Secondly, embodiments of this application also provide a battery device, including the aforementioned cylindrical battery cell.

[0086] Thirdly, embodiments of this application also provide an electrical device, including the aforementioned cylindrical battery cell, wherein the cylindrical battery cell is used to provide electrical energy. Attached Figure Description

[0087] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0088] Figure 1 is a structural schematic diagram of a vehicle provided in some embodiments of this application;

[0089] Figure 2 is an exploded view of the structure of a battery device provided in some embodiments of this application;

[0090] Figure 3 is a schematic diagram of the structure of a cylindrical battery cell provided in some embodiments of this application;

[0091] Figure 4 is an exploded view of the structure of a cylindrical battery cell provided in some embodiments of this application;

[0092] Figure 5 is a cross-sectional view of a cylindrical battery cell provided in some embodiments of this application;

[0093] Figure 6 is a partial enlarged view of point A of the cylindrical battery cell shown in Figure 5;

[0094] Figure 7 is a cross-sectional view of a cylindrical battery cell provided in some embodiments of this application;

[0095] Figure 8 is a partial enlarged view of point B of the cylindrical battery cell shown in Figure 7;

[0096] Figure 9 is a schematic diagram of the structure of the first current collection component provided in some embodiments of this application;

[0097] Figure 10 is a front view of a first current collector component provided in a first direction according to some embodiments of this application;

[0098] Figure 11 is a cross-sectional view of a cylindrical battery cell provided in some embodiments of this application;

[0099] Figure 12 is a partial enlarged view of point C of the cylindrical battery cell shown in Figure 11;

[0100] Figure 13 is a partial cross-sectional view of a cylindrical battery cell provided in some other embodiments of this application.

[0101] Icons: 1000 - Vehicle; 100 - Battery assembly; 10 - Housing; 11 - First housing body; 12 - Second housing body; 20 - Cylindrical battery cell; 21 - Casing; 211 - Wall; 2111 - Main body area; 2112 - First connection area; 2112a - First surface; 212 - Housing; 2121 - Opening; 2122 - Receiving cavity; 2123 - Bottom wall; 2123a - Mounting hole; 2124 - Side wall; 2124a - First protrusion; 2124b - First groove; 2124c - Flanged edge ; 213-End cap; 2131-Second protrusion; 2132-Second groove; 2133-Pressure relief groove; 22-Electrode assembly; 221-Main body; 222-First electrode tab; 223-Second electrode tab; 23-First current collector; 231-Body area; 232-Second connection area; 233-Transition area; 2331-Bending section; 234-Exhaust gap; 24-Connection part; 25-Electrode terminal; 26-Second current collector; 27-Seal; 200-Controller; 300-Motor; X-First direction. Detailed Implementation

[0102] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0103] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in the description of this application is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms "comprising" and "having," and any variations thereof, in the description, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the description, claims, or accompanying drawings of this application are used to distinguish different objects, not to describe a specific order or hierarchy.

[0104] In this application, the reference to "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 in the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment that is mutually exclusive with other embodiments.

[0105] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "attachment" 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 direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0106] In this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, in this application, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0107] In the embodiments of this application, the same reference numerals denote the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood 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 and should not constitute any limitation on this application.

[0108] In this application, "multiple" means two or more (including two).

[0109] In this embodiment of the application, the battery cell can be a secondary battery, which refers to a battery cell that can be recharged to activate the active materials and continue to be used after the battery cell has been discharged.

[0110] The battery cell can be a lithium-ion battery, sodium-ion battery, sodium-lithium-ion battery, lithium metal battery, sodium metal battery, lithium-sulfur battery, magnesium-ion battery, nickel-metal hydride battery, nickel-cadmium battery, lead-acid battery, etc., and the embodiments of this application are not limited to this.

[0111] A single battery cell typically includes an electrode assembly. The electrode assembly includes a positive electrode, a negative electrode, and a separator. During the charging and discharging process of a single battery cell, active ions (such as lithium ions) repeatedly insert and extract between the positive and negative electrodes. The separator, positioned between the positive and negative electrodes, prevents short circuits while allowing active ions to pass through.

[0112] In some embodiments, the positive electrode may be a positive electrode sheet, which may include a positive electrode current collector and a positive electrode active material disposed on at least one surface of the positive electrode current collector.

[0113] As an example, the positive current collector has two surfaces opposite each other in its own thickness direction, and the positive active material is disposed on either or both of the two opposite surfaces of the positive current collector.

[0114] As an example, the positive electrode current collector can be a metal foil or a composite current collector. For example, as a metal foil, it can be aluminum with a silver-plated surface, stainless steel with a silver-plated surface, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel, or titanium, etc. Composite current collectors can include a polymer material base layer and a metal layer. Composite current collectors can be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0115] As an example, the positive electrode active material may include at least one of the following materials: lithium phosphate, lithium transition metal oxide, and their respective modified compounds. However, this application is not limited to these materials, and other conventional materials that can be used as battery positive electrode active materials may also be used. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium phosphate may include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), lithium iron phosphate and carbon composites, lithium manganese phosphate (such as LiMnPO4), lithium manganese phosphate and carbon composites, lithium iron manganese phosphate, and lithium iron manganese phosphate and carbon composites. Examples of lithium transition metal oxide may include, but are not limited to, lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, and lithium nickel cobalt manganese oxide (such as LiNi). 1 / 3 Co 1 / 3 Mn 1 / 3O2 (also known as NCM) 333 LiNi 0.5 Co 0.2 Mn 0.3 O2 (also known as NCM) 523 LiNi 0.5 Co 0.25 Mn 0.25 O2 (also known as NCM) 211 LiNi 0.6 Co 0.2 Mn 0.2 O2 (also known as NCM) 622 LiNi 0.8 Co 0.1 Mn 0.1 O2 (also known as NCM) 811 ), lithium nickel cobalt aluminum oxide (such as LiNi) 0.85 Co 0.15 Al 0.05 At least one of O2 and its modified compounds.

[0116] In some embodiments, the positive electrode can be a foamed metal. The foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloys, etc. When foamed metal is used as the positive electrode, the surface of the foamed metal may or may not contain a positive electrode active material. As an example, lithium source material, potassium metal, or sodium metal can also be filled and / or deposited within the foamed metal, where the lithium source material is lithium metal and / or a lithium-rich material.

[0117] In some embodiments, the negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector.

[0118] As an example, the negative electrode current collector can be a metal foil, a foamed metal, or a composite current collector. For example, as a metal foil, it can be silver-treated aluminum or stainless steel, stainless steel, copper, aluminum, nickel, carbon electrode, nickel, or titanium, etc. Foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloy, etc. Composite current collectors can include a polymer material base layer and a metal layer. Composite current collectors can be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0119] As an example, the negative electrode sheet may include a negative electrode current collector and a negative electrode active material disposed on at least one surface of the negative electrode current collector.

[0120] As an example, the negative electrode current collector has two surfaces opposite each other in its own thickness direction, and the negative electrode active material is disposed on either or both of the two opposite surfaces of the negative electrode current collector.

[0121] As an example, the negative electrode active material may be a negative electrode active material known in the art for use in battery cells. As an example, the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate, etc. Silicon-based materials may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. Tin-based materials may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys. However, this application is not limited to these materials, and other conventional materials that can be used as battery negative electrode active materials may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0122] In some embodiments, the positive current collector can be made of aluminum, and the negative current collector can be made of copper.

[0123] In some embodiments, the electrode assembly further includes an isolator disposed between the positive and negative electrodes.

[0124] In some embodiments, the separator is a separator membrane. The separator membrane can be of various types, and any known porous separator membrane with good chemical and mechanical stability can be selected.

[0125] As an example, the material of the separator may include at least one of glass fiber, nonwoven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator may be a single-layer film or a multi-layer composite film. When the separator is a multi-layer composite film, the materials of each layer may be the same or different. The separator may be a separate component located between the positive and negative electrodes, or it may be attached to the surfaces of the positive and negative electrodes.

[0126] In some embodiments, the separator is a solid electrolyte. The solid electrolyte is disposed between the positive and negative electrodes, serving both to transport ions and to isolate the positive and negative electrodes.

[0127] In some embodiments, the battery cell also includes an electrolyte, which acts as a conductor of ions between the positive and negative electrodes. The electrolyte can be liquid, gel-like, or solid. Liquid electrolytes include electrolyte salts and solvents.

[0128] In some embodiments, the electrolyte salt may include at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalate borate, lithium dioxalate borate, lithium difluorodioxalate phosphate, and lithium tetrafluorooxalate phosphate.

[0129] In some embodiments, the solvent may include at least one selected from ethylene carbonate, propylene carbonate, methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butyl carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone. The solvent may also be an ether solvent. Ether solvents may include one or more selected from ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyl tetrahydrofuran, diphenyl ether, and crown ethers.

[0130] Among them, gel electrolytes include a polymer-based electrolyte backbone network combined with an ionic liquid-lithium salt.

[0131] Solid electrolytes include polymer solid electrolytes, inorganic solid electrolytes, and composite solid electrolytes.

[0132] As an example, polymer solid electrolytes can be polyether (polyoxyethylene), polysiloxane, polycarbonate, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, monoionic polymers, polyionic liquids-lithium salts, cellulose, etc.

[0133] As an example, inorganic solid electrolytes may include one or more of the following: oxide solid electrolytes (crystalline perovskite, sodium superconducting ion conductor, garnet, amorphous LiPON thin film), sulfide solid electrolytes (crystalline lithium superconducting ion conductor (lithium germanium phosphate sulfide, silver sulfide germanium ore), amorphous sulfides), halide solid electrolytes, nitride solid electrolytes, and hydride solid electrolytes.

[0134] As an example, composite solid electrolytes are formed by adding inorganic solid electrolyte fillers to polymer solid electrolytes.

[0135] In some implementations, the electrode assembly has a wound structure. The positive and negative electrode sheets are wound into a wound structure.

[0136] In some embodiments, the electrode assembly can be cylindrical, flat, or polygonal, etc.

[0137] In some embodiments, the electrode assembly is provided with tabs that allow current to be drawn from the electrode assembly. The tabs include a positive tab and a negative tab.

[0138] In some embodiments, the battery cell may include a housing. The housing is used to encapsulate components such as electrode assemblies and electrolytes. The housing may be made of steel, aluminum, plastic (such as polypropylene), composite metal (such as copper-aluminum composite), or aluminum-plastic film, etc.

[0139] As an example, a single battery cell can be cylindrical, i.e., a cylindrical battery cell.

[0140] The battery apparatus mentioned in the embodiments of this application may include one or more battery cell assemblies for providing voltage and capacity. A battery cell assembly may include multiple battery cells connected in series, parallel, or mixed connections via a busbar.

[0141] In some embodiments, a battery cell assembly is typically formed by arranging multiple battery cells; as an example, a battery cell assembly can be a battery module, which is formed by arranging and fixing multiple battery cells together to form a single module. As an example, a battery module can be formed by bundling multiple battery cells together with cable ties.

[0142] In some embodiments, the battery device may be a battery pack, which includes a housing and one or more individual battery cells housed within the housing.

[0143] As an example, the battery cell assembly can be a battery module, which can be housed in a housing by fixing the battery module in the housing.

[0144] As an example, battery cell assemblies can also be housed in a housing by directly fixing multiple battery cells to the housing.

[0145] As an example, the enclosure may include a first enclosure body and a second enclosure body. The first enclosure body and the second enclosure body are fastened together to form a closed space inside the enclosure to house the individual battery cells. Here, "closed" refers to covering or shutting down; it can be sealed or not sealed. The first enclosure body may be a top cover or a bottom plate.

[0146] As an example, the enclosure may include a top cover, a frame, and a bottom plate. The top cover and bottom plate are connected to the frame, creating an enclosed space inside the enclosure to house the individual battery cells.

[0147] As an example, the housing can be part of the vehicle's chassis structure. For instance, the housing's roof can be at least part of the vehicle's floor, or the housing's frame can be at least part of the vehicle's crossbeams and longitudinal beams.

[0148] In some embodiments, the battery device refers to an energy storage device, which includes a housing with a door on at least one side. Energy storage devices include energy storage containers, energy storage cabinets, etc.

[0149] Battery devices possess outstanding advantages such as high energy density, low environmental pollution, high power density, long service life, wide applicability, and low self-discharge coefficient, making them an important component of today's new energy development. The development of battery technology must simultaneously consider multiple design factors, such as performance parameters like energy density, cycle life, discharge capacity, and charge / discharge rate. Furthermore, the safety of the battery device must also be taken into account.

[0150] For a typical cylindrical battery cell, it usually includes a casing and an electrode assembly housed within the casing. The electrode assembly has tabs that are connected to one wall of the casing, allowing the cylindrical battery cell to input or output electrical energy through the casing. In related technologies, to reduce the assembly difficulty between the tabs and the casing, a current collector is usually installed inside the casing. The casing and the tabs are welded together through the current collector to achieve electrical connection between them. However, due to the complex operating conditions of cylindrical battery cells, the electrode assembly often experiences vibration or shaking within the casing. This structure of cylindrical battery cells is highly susceptible to rigid tension between the current collector and the casing, as well as between the current collector and the tabs, during use. This can lead to the risk of weld detachment between the current collector and the casing, resulting in connection failure between the electrode assembly and the casing during use. Consequently, this negatively impacts the stability and lifespan of the cylindrical battery cell.

[0151] Based on the above considerations, in order to solve the problems of low stability and short service life of cylindrical battery cells, this application provides a cylindrical battery cell, which includes a shell, an electrode assembly, and a first current collector. The shell has a wall. The electrode assembly is disposed inside the shell and has a first tab. The first current collector is located inside the shell, and the first tab is electrically connected to the wall through the first current collector. The wall includes a main body region and a first connecting region that are interconnected. The first current collector includes a body region and a second connecting region. The body region is connected to the first tab, and the second connecting region is welded to the wall to form a connecting part. A portion of the connecting part is embedded in the first connecting region, and the connecting part is connected to the main body region through the first connecting region. The hardness of the first connecting region is less than that of the main body region.

[0152] In this type of cylindrical battery cell, a first current collector is disposed inside the casing. The body region of the first current collector is connected to the first tab of the electrode assembly, and the second connection region of the first current collector is welded to the wall of the casing. This allows the cylindrical battery cell to input or output electrical energy through the wall. The wall of the casing forms an interconnected body region and a first connection region. By setting the hardness of the first connection region to be less than that of the body region, and by partially embedding the connection portion formed by welding the second connection region of the first current collector to the wall of the casing within the first connection region, the connection portion is a structure that connects to the body region through the first connection region. In other words, the second connection region of the first current collector is connected to the first connection region. The structure of the connection area is formed by welding the connection areas together, so that the connection area is connected to the main body area through the first connection area. When the second connection area of ​​the first current collector is pulled on the wall due to the shaking of the electrode assembly during use, the first connection area can play a certain buffering role between the connection area and the main body area. This can alleviate the rigid pulling between the second connection area and the wall of the first current collector, which helps to reduce the phenomenon of weld detachment between the second connection area and the wall of the first current collector. In this way, the risk of connection failure between the electrode assembly and the wall of the casing can be reduced during the use of the cylindrical battery cell, thereby improving the stability and service life of the cylindrical battery cell.

[0153] The cylindrical battery cells disclosed in this application can be used, but are not limited to, in electrical devices such as vehicles, ships, or aircraft. A power system for such an electrical device can be constructed using the cylindrical battery cells and battery assembly disclosed in this application. This helps to alleviate the problem of electrode assembly and casing connection failures during the use of cylindrical battery cells, thereby improving the stability and service life of the cylindrical battery cells.

[0154] This application provides an electrical device that uses a cylindrical battery cell or battery assembly as a power source. The electrical device can be, but is not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric vehicles, electric cars, ships, spacecraft, etc. Electric toys can include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.

[0155] For ease of explanation, the following embodiments will be described using a vehicle as an example of an electrical device according to an embodiment of this application.

[0156] Please refer to Figure 1, which is a structural schematic diagram of a vehicle 1000 provided in some embodiments of this application. The vehicle 1000 can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. New energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. A battery device 100 is installed inside the vehicle 1000. The battery device 100 can be located at the bottom, front, or rear of the vehicle 1000. The battery device 100 can be used to power the vehicle 1000; for example, it can serve as the vehicle's operating power source or general power source. The vehicle 1000 may also include a controller 200 and a motor 300. The controller 200 controls the battery device 100 to supply power to the motor 300, for example, to meet the power needs of the vehicle 1000 during startup, navigation, and driving.

[0157] In some embodiments of this application, the battery device 100 can not only serve as the operating power or power source for the vehicle 1000, but also as the driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0158] Please refer to Figures 2 and 3. Figure 2 is an exploded view of the structure of a battery device 100 provided in some embodiments of this application, and Figure 3 is a schematic diagram of the structure of a cylindrical battery cell 20 provided in some embodiments of this application. The battery device 100 includes a housing 10 and a cylindrical battery cell 20, which is housed within the housing 10.

[0159] The housing 10 provides an assembly space for the cylindrical battery cell 20, and the housing 10 can adopt various structures. In some embodiments, the housing 10 may include a first housing body 11 and a second housing body 12, which overlap each other, and together define an assembly space for accommodating the cylindrical battery cell 20. The second housing body 12 may be a hollow structure with one end open, and the first housing body 11 may be a plate-like structure, with the first housing body 11 covering the open side of the second housing body 12 so that the first housing body 11 and the second housing body 12 together define the assembly space; alternatively, the first housing body 11 and the second housing body 12 may both be hollow structures with one side open, with the open side of the first housing body 11 covering the open side of the second housing body 12.

[0160] Of course, the box 10 formed by the first box body 11 and the second box body 12 can be of various shapes, such as a cylinder, a cuboid, or a cube. For example, in Figure 2, the shape of the box 10 is a cuboid.

[0161] In the battery device 100, there can be one or more cylindrical battery cells 20 disposed within the housing 10. When there are multiple cylindrical battery cells 20 disposed within the housing 10, the multiple cylindrical battery cells 20 can be connected in series, in parallel, or in a mixed manner. A mixed connection means that the multiple cylindrical battery cells 20 are connected in both series and parallel. The multiple cylindrical battery cells 20 can be directly connected in series, in parallel, or in a mixed manner, and then the whole assembly of the multiple cylindrical battery cells 20 is housed within the housing 10. Of course, the battery device 100 can also be in the form of multiple cylindrical battery cells 20 first connected in series, in parallel, or in a mixed manner to form a battery module, and then the multiple battery modules are connected in series, in parallel, or in a mixed manner to form a whole assembly, which is then housed within the housing 10.

[0162] In some embodiments, the battery device 100 may also include other structures. For example, the battery device 100 may also include a busbar for connecting a plurality of cylindrical battery cells 20 to achieve electrical connection between the plurality of cylindrical battery cells 20.

[0163] Each cylindrical battery cell 20 can be a secondary battery or a primary battery; it can also be a lithium-sulfur battery, a sodium-ion battery or a magnesium-ion battery, but is not limited to these.

[0164] According to some embodiments of this application, referring to FIG3, and further referring to FIG4, 5 and 6, FIG4 is an exploded view of the structure of a cylindrical battery cell 20 provided in some embodiments of this application, FIG5 is a cross-sectional view of a cylindrical battery cell 20 provided in some embodiments of this application, and FIG6 is a partial enlarged view of point A of the cylindrical battery cell 20 shown in FIG5. This application provides a cylindrical battery cell 20, which includes a housing 21, an electrode assembly 22 and a first current collector 23. The housing 21 has a wall portion 211. The electrode assembly 22 is disposed within the housing 21 and has a first tab 222. The first current collector 23 is located within the housing 21, and the first tab 222 is electrically connected to the wall portion 211 through the first current collector 23. The wall portion 211 includes a main body region 2111 and a first connecting region 2112 that are connected to each other. The first current collector 23 includes a body region 231 and a second connecting region 232. The body region 231 is connected to the first electrode tab 222. The second connecting region 232 is welded to the wall portion 211 to form a connecting portion 24. A portion of the connecting portion 24 is embedded in the first connecting region 2112, and the connecting portion 24 is connected to the main body region 2111 through the first connecting region 2112. The hardness of the first connecting region 2112 is less than the hardness of the main body region 2111.

[0165] The outer shell 21 can also be used to contain electrolytes, such as electrolyte solutions. The outer shell 21 can have various structural forms. The outer shell 21 can also be made of various materials, such as copper, iron, aluminum, steel, aluminum alloy, etc.

[0166] In some embodiments, the housing 21 may include a housing 212 and an end cap 213. The housing 212 has an internal cavity 2122 with an opening 2121. The opening 2121 is located at one end of the housing 212 in the first direction X, that is, the housing 212 is a hollow structure with one end open in the first direction X. The end cap 213 covers the opening 2121 of the housing 212 and forms a sealed connection to form a sealed space for accommodating the electrode assembly 22 and the electrolyte. Correspondingly, the thickness direction of the end cap 213 is the first direction X.

[0167] The housing 212 may include a bottom wall 2123 and a side wall 2124. The side wall 2124 surrounds the bottom wall 2123. Along the first direction X, one end of the side wall 2124 is connected to the bottom wall 2123, and the other end forms an opening 2121. The end cap 213 is disposed opposite to the bottom wall 2123 in the first direction X.

[0168] Optionally, the wall portion 211, which is welded to the second connection area 232 of the first current collector 23, can be the side wall 2124 or the bottom wall 2123 of the housing 212, or it can be the end cap 213 of the outer shell 21. For example, in Figures 3 and 4, the wall portion 211 is the side wall 2124 of the housing 212. Correspondingly, the second connection area 232 of the first current collector 23 is welded to the side wall 2124 of the housing 212 to form a connection portion 24, and a first connection area 2112 is formed around the connection portion 24. The other areas of the side wall 2124 are the main body area 2111, so that the connection portion 24 is a structure that is connected to the main body area 2111 through the first connection area 2112. Of course, in other embodiments, the wall portion 211 can also be the bottom wall 2123 of the housing 212, or it can be the end cap 213 of the outer shell 21.

[0169] The cylindrical battery cell 20 is cylindrical, and the axial direction of the cylindrical battery cell 20 is the first direction X, that is, the central axis of the cylindrical battery cell 20 extends along the first direction X. The radial direction of the cylindrical battery cell 20 is perpendicular to the first direction X. The radial direction of the cylindrical battery cell 20 is in the projection plane perpendicular to the first direction X. The central axis of the cylindrical battery cell 20 points to the outer peripheral surface of the cylindrical battery cell 20 or the outer peripheral surface of the cylindrical battery cell 20 points to the central axis of the cylindrical battery cell 20. Correspondingly, the side wall 2124 of the housing 212 is also a cylindrical structure, and the central axis of the housing 212 extends along the first direction X, so that the projection of the end cap 213 in the first direction X is circular.

[0170] Understandably, the outer casing 21 is not limited to the structure described above. The outer casing 21 can also be other structures. For example, the outer casing 21 includes a shell 212 and two end caps 213. The shell 212 is a hollow structure with openings 2121 on both sides. One end cap 213 is fitted onto one opening 2121 of the shell 212 and forms a sealed connection to form a sealed space for accommodating the electrode assembly 22 and the electrolyte. That is, the shell 212 of the outer casing 21 only includes a side wall 2124. The side wall 2124 is a hollow structure with openings 2121 at both ends in the first direction X. The two end caps 213 are fitted onto the openings 2121 at both ends of the side wall 2124 in the first direction X.

[0171] It should be noted that the electrode assembly 22 is the component in the cylindrical battery cell 20 where the electrochemical reaction occurs. The electrode assembly 22 includes a main body 221, a first tab 222, and a second tab 223. The main body 221 is the main component of the electrode assembly 22 in the cylindrical battery cell 20 where the electrochemical reaction occurs, while the first tab 222 and the second tab 223 serve to output or input electrical energy to the electrode assembly 22. The structure of the main body 221 of the electrode assembly 22 can be varied. For example, in Figure 4, the main body 221 of the electrode assembly 22 is a wound structure formed by winding a portion of the positive electrode, a separator, and a portion of the negative electrode, and the main body 221 of the electrode assembly 22 has a cylindrical structure. The central axis of the main body 221 of the electrode assembly 22 extends along the first direction X.

[0172] For example, the separator is a separator membrane, and the main material of the separator membrane can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene and polyvinylidene fluoride.

[0173] Optionally, the electrode assembly 22 housed within the housing 21 can be one or more. For example, in Figure 4, only one electrode assembly 22 is provided within the housing 21 of the cylindrical battery cell 20. Of course, the structure of the cylindrical battery cell 20 is not limited to this; in other embodiments, the electrode assembly 22 housed within the housing 21 can be two, three, four, five, six, seven, or eight, etc.

[0174] The first electrode 222 and the second electrode 223 have opposite polarities. The first electrode 222 and the second electrode 223 are used as the positive and negative electrodes of the input or output electrode assembly 22, respectively. In Figures 5 and 6, the first electrode 222 and the second electrode 223 are respectively connected to the two ends of the main body 221 in the first direction X. The first electrode 222 is located at the end of the main body 221 facing the end cover 213, and the second electrode 223 is located at the end of the main body 221 away from the end cover 213.

[0175] It should be noted that if the first tab 222 is the positive tab of the electrode assembly 22, then the first tab 222 is a component formed by stacking and connecting the regions on the positive electrode sheet that are not coated with the positive active material layer. Correspondingly, if the second tab 223 is the negative tab of the electrode assembly 22, then the second tab 223 is a component formed by stacking and connecting the regions on the negative electrode sheet that are not coated with the negative active material layer. Conversely, if the first tab 222 is the negative tab of the output electrode assembly 22, then the first tab 222 is a component formed by stacking and connecting the regions on the negative electrode sheet that are not coated with the negative active material layer. Correspondingly, if the second tab 223 is the positive tab of the electrode assembly 22, then the second tab 223 is a component formed by stacking and connecting the regions on the positive electrode sheet that are not coated with the positive active material layer.

[0176] The second connecting area 232 of the first current collector 23 is welded to the wall portion 211 to form a connecting portion 24. It should be noted that the connecting portion 24 is a region where the second connecting area 232 of the first current collector 23 and the wall portion 211 are welded together to form a region that is mutually fused or a region where a weld mark is formed.

[0177] Optionally, the welding connection between the first current collector 23 and the wall 211 can be of various types, such as laser welding or ultrasonic welding.

[0178] The body region 231 of the first current collector 23 is connected to the first electrode 222, so that the first electrode 222 is a structure that is interconnected with the wall portion 211 through the first current collector 23, so as to realize the electrical connection between the electrode assembly 22 and the wall portion 211, thereby making the wall portion 211 an output electrode of the cylindrical battery cell 20.

[0179] The body region 231 of the first current collector 23 is disposed at one end of the electrode assembly 22 in the first direction X near the first protrusion 2124a, and the body region 231 is connected to the first electrode tab 222 to realize the electrical connection between the first current collector 23 and the first electrode tab 222. Optionally, the body region 231 is connected to the side of the first electrode tab 222 away from the main body 221 in the first direction X. The connection structure between the body region 231 and the first electrode tab 222 can be various, such as welding connection or bonding.

[0180] The second connection area 232 is located on the side of the body area 231 facing the end cap 213 along the first direction X, and the second connection area 232 is spaced apart from the body area 231. That is, the body area 231 and the second connection area 232 are arranged at intervals along the first direction X, and the second connection area 232 is closer to the end cap 213 in the first direction X than the body area 231.

[0181] The wall portion 211 includes a main body region 2111 and a first connecting region 2112 that are interconnected. A portion of the connecting portion 24 is embedded in the first connecting region 2112, and the connecting portion 24 is connected to the main body region 2111 through the first connecting region 2112. That is, the second connecting region 232 of the first current collector 23 is a structure formed by welding the connecting portion 24 to the first connecting region 2112 of the wall portion 211, and the first connecting region 2112 covers a portion of the connecting portion 24, so that the connecting portion 24 is a structure that is interconnected with the main body region 2111 through the first connecting region 2112. It should be noted that the connecting part 24 is partially embedded in the first current collecting member 23, and the connecting part 24 is partially embedded in the wall part 211. The first connecting area 2112 of the wall part 211 is a structure that covers the outer side of the part of the connecting part 24 embedded in the wall part 211, and the main body area 2111 is the area of ​​the wall part 211 located on the outer periphery of the first connecting area 2112, that is, the main body area 2111 is the conventional area of ​​the wall part 211.

[0182] Optionally, the first connection area 2112 may be formed by local softening of the wall portion 211 before the second connection area 232 and the wall portion 211 of the first current collector 23 are welded together, or the first connection area 2112 may be formed by controlling the welding power to reduce the hardness of the area around the connection portion 24 during the welding process of the second connection area 232 and the wall portion 211 of the first current collector 23.

[0183] It should be noted that in the stacking direction of the second connecting area 232 and the first connecting area 2112 of the first current collector 23, that is, in the first direction X, the connecting part 24 can be a structure that penetrates the first connecting area 2112 or a structure that does not penetrate the first connecting area 2112. For example, in FIG6, the connecting part 24 does not penetrate the first connecting area 2112 in the first direction X. Correspondingly, a portion of the first connecting area 2112 is located on the outer periphery of the connecting part 24, that is, a portion of the first connecting area 2112 is arranged around the connecting part 24, and a portion of the first connecting area 2112 is located on one side of the connecting part 24 in the first direction X. In other words, the connecting part 24 is a structure in which one end in the first direction X is inserted into the first connecting area 2112. Of course, in other embodiments, the connecting part 24 can also be a structure that penetrates the first connecting area 2112 in the first direction X. Correspondingly, the first connecting area 2112 is only a structure located on the outer periphery of the connecting part 24, such that the first connecting area 2112 is arranged around the connecting part 24.

[0184] The statement that the hardness of the first connecting region 2112 is less than that of the main body region 2111 means that the Vickers hardness of the first connecting region 2112 is less than that of the main body region 2111. The test method can refer to the test method for Vickers hardness of metals in the national standard GB / T 4340.1-2009.

[0185] Optionally, the first current collector 23 can be made of various materials, such as copper, iron, aluminum, steel or aluminum alloy.

[0186] In some embodiments, the first current collector 23 is made of copper, and the surface of the wall 211 is covered with a plating layer made of steel and the plating layer made of nickel. This structure of the cylindrical battery cell 20 can further improve the welding reliability between the wall 211 and the first current collector 23, and also reduce the risk of rust and corrosion on the wall 211.

[0187] In some embodiments, as shown in Figures 3, 4 and 5, the cylindrical battery cell 20 may further include an electrode terminal 25. The electrode terminal 25 is insulatedly mounted on a wall of the housing 21 facing the second tab 223 in the first direction X. The electrode terminal 25 is electrically connected to the second tab 223, so that the electrode terminal 25 serves as another output electrode of the cylindrical battery cell 20, thereby enabling the input or output of electrical energy of the cylindrical battery cell 20 through the electrode terminal 25 and the wall portion 211.

[0188] The electrode terminal 25 is insulatedly mounted on a wall of the housing 21 facing the second tab 223 in the first direction X. That is, the electrode terminal 25 is mounted on the end of the housing 212 away from the end cover 213 in the first direction X, and an insulating element is provided between the electrode terminal 25 and the housing 21, so that no electrical connection is formed between the electrode terminal 25 and the housing 21.

[0189] Referring to Figure 5, the electrode terminal 25 is riveted to the bottom wall 2123 of the housing 212. That is, the bottom wall 2123 of the housing 212 has a mounting hole 2123a. The mounting hole 2123a passes through both sides of the bottom wall 2123 of the housing 212 along the first direction X. A portion of the electrode terminal 25 passes through the mounting hole 2123a. The electrode terminal 25 has a first clamping part located on the side of the bottom wall 2123 of the housing 212 facing the electrode assembly 22 and a second clamping part located on the side of the bottom wall 2123 of the housing 212 away from the electrode assembly 22. At least a portion of the bottom wall 2123 of the housing 212 is located between the first clamping part and the second clamping part in the first direction X, so that the first clamping part and the second clamping part can cooperate to clamp the bottom wall 2123 of the housing 212, so as to realize the riveting of the electrode terminal 25 to the bottom wall 2123 of the housing 212. Of course, in other embodiments, the electrode terminal 25 may also be a structure that is snapped or glued to the housing 21.

[0190] For example, the electrode terminal 25 can be made of various materials, such as copper, iron, aluminum, steel or aluminum alloy.

[0191] In some embodiments, as shown in Figures 4 and 5, the cylindrical battery cell 20 may further include a second current collector 26, which is disposed in a first direction X between the second tab 223 and the electrode terminal 25 of the electrode assembly 22. The second current collector 26 connects the second tab 223 and the electrode terminal 25 to electrically connect the electrode assembly 22 and the electrode terminal 25.

[0192] Optionally, the connection structure between the second current collector 26 and the second electrode tab 223, and between the second current collector 26 and the electrode terminal 25, can be various, such as welding connection or bonding.

[0193] For example, the material of the second current collector 26 can be various, such as copper, iron, aluminum, steel or aluminum alloy.

[0194] It should be noted that in other embodiments, the second tab 223 of the electrode assembly 22 may also be a structure that is directly connected to the electrode terminal 25, such as by welding or bonding.

[0195] In some embodiments, the cylindrical battery cell 20 may further include a pressure relief component disposed on the housing 21, which is used to release the internal pressure of the cylindrical battery cell 20 when the internal pressure or temperature of the cylindrical battery cell 20 reaches a predetermined value.

[0196] The pressure relief component can be located on the end cap 213 of the outer casing 21 or on the housing 212. Similarly, the pressure relief component and the outer casing 21 can be integrally formed or separate components. If the pressure relief component and the outer casing 21 are integrally formed, the pressure relief component is part of the outer casing 21, and the weak structure on the pressure relief component for pressure relief is the area on the outer casing 21 where a weak structure is formed. This allows the outer casing 21 to be configured to at least partially crack along the weak structure when the cylindrical battery cell 20 is depressurized, thereby releasing the internal pressure of the cylindrical battery cell 20. Of course, in other embodiments, the pressure relief component and the outer casing 21 can also be separate components. The pressure relief component can be connected to the outer casing 21 by welding or other means. Correspondingly, the pressure relief component can be a component such as an explosion-proof valve, explosion-proof disc, gas valve, pressure relief valve, or safety valve.

[0197] In this embodiment, a first current collector 23 is provided inside the outer casing 21. The body region 231 of the first current collector 23 is connected to the first tab 222 of the electrode assembly 22, and the second connection region 232 of the first current collector 23 is welded to the wall 211 of the outer casing 21, so that the cylindrical battery cell 20 can input or output electrical energy through the wall 211. The wall 211 of the outer casing 21 is formed with a main body region 2111 and a first connection region 2112 that are connected to each other. By setting the hardness of the first connection region 2112 to be less than the hardness of the main body region 2111, and by welding the second connection region 232 of the first current collector 23 to the wall 211 of the outer casing 21, a portion of the connection part 24 formed by welding the second connection region 232 of the first current collector 23 to the wall 211 of the outer casing 21 is embedded in the first connection region 2112, so that the connection part 24 is a structure that is connected to the main body region 2111 through the first connection region 2112, that is, the second connection region 232 of the first current collector 23. 2. The structure is formed by welding the first connection area 2112 to form the connection part 24, so that the connection part 24 is connected to the main body area 2111 through the first connection area 2112. When the cylindrical battery cell 20 with this structure is used, the second connection area 232 of the first current collector 23 pulls on the wall 211 due to the shaking of the electrode assembly 22. The first connection area 2112 can play a certain buffering role between the connection part 24 and the main body area 2111, thereby alleviating the rigid pulling between the second connection area 232 and the wall 211 of the first current collector 23. This helps to reduce the phenomenon of weld detachment between the second connection area 232 and the wall 211 of the first current collector 23. In this way, the risk of connection failure between the electrode assembly 22 and the wall 211 of the outer casing 21 can be reduced during the use of the cylindrical battery cell 20, so as to improve the stability and service life of the cylindrical battery cell 20.

[0198] According to some embodiments of this application, the first connection area 2112 includes two first sub-connection areas, which are located on both sides of the connection portion 24 in the width direction of the connection portion 24.

[0199] The width direction of the connecting part 24 is perpendicular to the extension direction of the connecting part 24. If the connecting part 24 is a strip structure, the two first sub-connecting areas are located on both sides in a direction perpendicular to the length direction of the connecting part 24. If the connecting part 24 is an arc-shaped structure or a ring structure, the two first sub-connecting areas are located on the inner and outer peripheral sides of the connecting part 24.

[0200] For example, in this embodiment of the application, the connecting portion 24 is a structure that is partially embedded in the first connecting area 2112, such that a portion of the first connecting area 2112 surrounds the outside of the connecting portion 24.

[0201] It should be noted that, referring to Figure 6, in the embodiment where the connecting part 24 does not penetrate the first connecting area 2112 along the first direction X, that is, the connecting part 24 is a structure in which one end in the first direction X is inserted into the first connecting area 2112, correspondingly, the first connecting area 2112 also includes a second sub-connecting area, which is located on one side of the connecting part 24 in the first direction X, and the second sub-connecting area is connected to both first sub-connecting areas.

[0202] In this embodiment, the first connection area 2112 has two first sub-connection areas located on both sides of the connection portion 24 in the width direction of the connection portion 24, so that each side of the connection portion 24 is connected to the main body area 2111 through a first sub-connection area. This allows the first connection area 2112 to play a certain buffering role on both sides of the connection portion 24, which helps to further alleviate the rigid tension between the first current collector 23 and the wall portion 211, thereby further reducing the phenomenon of weld detachment between the first current collector 23 and the wall portion 211, and further reducing the risk of connection failure between the electrode assembly 22 and the wall portion 211 of the outer shell 21.

[0203] According to some embodiments of this application, referring to FIG6, the second connecting region 232 and the first connecting region 2112 are stacked, and the connecting portion 24 connects the second connecting region 232 and the first connecting region 2112. The first connecting region 2112 has a first surface 2112a facing the second connecting region 232. The minimum distance between the orthographic projection of the portion of the connecting portion 24 embedded in the first connecting region 2112 and the outer edge of the first surface 2112a is L1, which satisfies 0.05mm≤L1≤2.5mm.

[0204] The second connection area 232 is the area where the first current collector 23 is welded to the wall 211. For example, the second connection area 232 and the first connection area 2112 are stacked along the first direction X.

[0205] The connecting part 24 connects the second connecting area 232 and the first connecting area 2112. That is, the first connecting area 2112 and the second connecting area 232 are welded together to form the connecting part 24, such that a portion of the connecting part 24 is embedded in the first connecting area 2112 and a portion of the connecting part 24 is embedded in the second connecting area 232.

[0206] The first connection region 2112 has a first surface 2112a facing the second connection region 232. The first surface 2112a is the surface of the first connection region 2112 facing the second connection region 232 in the stacking direction of the first connection region 2112 and the second connection region 232, and is also the surface of the first connection region 2112 facing the second connection region 232 in the first direction X.

[0207] For example, within the first surface 2112a, the minimum distance L1 between the orthographic projection of the portion of the connecting part 24 embedded in the first connecting area 2112 and the outer edge of the first surface 2112a can be 0.05mm, 0.06mm, 0.07mm, 0.08mm, 0.09mm, 0.1mm, 0.11mm, 0.12mm, 0.15mm, 0.18mm, 0.2mm, 0.22mm, or 0.25mm. , 0.28mm, 0.3mm, 0.35mm, 0.4mm, 0.45mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, 1.1mm, 1.2m m, 1.3mm, 1.4mm, 1.5mm, 1.6mm, 1.7mm, 1.8mm, 1.9mm, 2mm, 2.1mm, 2.2mm, 2.3mm, 2.4mm or 2.5mm, etc.

[0208] In this embodiment, the minimum distance between the orthographic projection of the portion of the connecting part 24 embedded in the first connecting area 2112 onto the first surface 2112a and the outer edge of the first surface 2112a is 0.05mm to 2.5mm. This makes the minimum size of the first connecting area 2112 between the connecting part 24 and the main body area 2111 0.05mm to 2.5mm. On the one hand, by setting the minimum distance between the orthographic projection of the portion of the connecting part 24 embedded in the first connecting area 2112 onto the first surface 2112a and the outer edge of the first surface 2112a to be greater than or equal to 0.05mm, the size of the buffer area between the connecting part 24 and the main body area 2111 can be increased, which is beneficial to improving the size of the buffer area between the connecting part 24 and the main body area 2111. The buffering effect can further alleviate the rigid tension between the second connecting area 232 and the wall 211 of the first current collector 23, thereby further reducing the phenomenon of weld detachment between the second connecting area 232 and the wall 211 of the first current collector 23. On the other hand, by setting the minimum distance between the orthographic projection of the part of the connecting part 24 embedded in the first connecting area 2112 in the first surface 2112a and the outer edge of the first surface 2112a to less than or equal to 2.5mm, the phenomenon of weakening the overall structural strength of the wall 211 caused by the excessive space occupied by the first connecting area 2112 can be alleviated. Thus, while realizing the buffering effect of the first connecting area 2112 between the connecting part 24 and the main body area 2111, the overall structural strength of the outer shell 21 can also be improved.

[0209] According to some embodiments of this application, the Vickers hardness value of the first connection region 2112 is greater than or equal to 50 and less than or equal to 180.

[0210] For example, the Vickers hardness of the first connection region 2112 can be 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120, 125, 130, 135, 140, 145, 150, 160, 170 or 180, etc.

[0211] In this embodiment, the Vickers hardness of the first connection area 2112 is 50 to 180. On the one hand, by setting the Vickers hardness of the first connection area 2112 to be greater than or equal to 50, the structural strength of the first connection area 2112 is improved, which helps to alleviate the phenomenon of cracking or damage that occurs when the first connection area 2112 and the first current collector 23 are assembled or used, thereby improving the stability of the cylindrical battery cell 20. On the other hand, by setting the Vickers hardness of the first connection area 2112 to be less than or equal to 180, the buffering effect of the first connection area 2112 between the connection part 24 and the main body area 2111 is improved, thereby further alleviating the rigid tension between the second connection area 232 and the wall part 211 of the first current collector 23, and further reducing the phenomenon of weld detachment between the second connection area 232 and the wall part 211 of the first current collector 23.

[0212] According to some embodiments of this application, the Vickers hardness value of the main body region 2111 is greater than or equal to 70 and less than or equal to 200.

[0213] For example, the Vickers hardness of the main body region 2111 can be 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120, 125, 130, 135, 140, 145, 150, 160, 170, 180, 190 or 200, etc.

[0214] In this embodiment, the Vickers hardness of the main body region 2111 is 70 to 200. On the one hand, by setting the Vickers hardness of the main body region 2111 to be greater than or equal to 70, the overall structural strength of the wall portion 211 is improved, which helps to alleviate phenomena such as cracking or damage of the wall portion 211 during use, thereby improving the stability of the cylindrical battery cell 20. On the other hand, by setting the Vickers hardness of the main body region 2111 to be less than or equal to 200, the molding and processing difficulty of the wall portion 211 is reduced, and the manufacturing cost of the cylindrical battery cell 20 is reduced.

[0215] According to some embodiments of this application, referring to Figures 4, 5 and 6, the axial direction of the cylindrical battery cell 20 is the first direction X. The outer casing 21 may include a housing 212 and an end cap 213. The housing 212 includes an integrally formed side wall 2124 and a bottom wall 2123. The side wall 2124 surrounds the bottom wall 2123. Along the first direction X, one end of the side wall 2124 is connected to the bottom wall 2123, and the other end forms an opening 2121. The side wall 2124 and the bottom wall 2123 together define a receiving cavity 2122. The electrode assembly 22 is received in the receiving cavity 2122. The end cap 213 closes the opening 2121. The wall portion 211 is either the side wall 2124 or the bottom wall 2123.

[0216] The shell 212 includes an integrally formed side wall 2124 and bottom wall 2123, that is, the side wall 2124 and bottom wall 2123 of the shell 212 are structures formed by an integral forming process, such as stamping or casting.

[0217] The sidewall 2124 surrounds the bottom wall 2123. Along the first direction X, one end of the sidewall 2124 is connected to the bottom wall 2123, and the other end is closed to form an opening 2121. That is to say, the sidewall 2124 is an annular structure surrounding the bottom wall 2123. The sidewall 2124 is a hollow structure with open ends in the first direction X, and one end of the sidewall 2124 in the first direction X is connected to the bottom wall 2123. In Figure 4, the outer shell 21 of the cylindrical battery cell 20 is a cylindrical structure, and the central axis of the outer shell 21 extends along the first direction X. Correspondingly, the sidewall 2124 is also a hollow cylindrical structure with the central axis extending along the first direction X, so that the projections of the bottom wall 2123 and the end cap 213 in the first direction X are both circular.

[0218] The wall portion 211 is either a side wall 2124 or a bottom wall 2123. That is, the second connection area 232 of the first current collector 23 can be a structure that is welded to the side wall 2124 of the housing 212 or a structure that is welded to the bottom wall 2123 of the housing 212. For example, in FIG6, the wall portion 211 is the side wall 2124 of the housing 212, such that the second connection area 232 of the first current collector 23 is a structure that is welded to the side wall 2124 of the housing 212 to form a connection portion 24, and such that the first connection area 2112 is formed on the side wall 2124 of the housing 212.

[0219] In this embodiment, by setting the sidewall 2124 or bottomwall 2123 of the housing 212 as a wall portion 211, the second connection area 232 of the first current collector 23 is a structure welded to the sidewall 2124 or bottomwall 2123 of the housing 212. This can alleviate the stress generated by the first current collector 23 pulling or torsion on the wall portion 211 and acting on the end cap 213, thereby reducing the risk of connection failure between the end cap 213 and the housing 212, and thus effectively improving the stability of the cylindrical battery cell 20 in use.

[0220] According to some embodiments of this application, referring to Figures 5 and 6, the wall portion 211 is a sidewall 2124. A first protrusion 2124a is formed on the side of the sidewall 2124 facing the receiving cavity 2122. Along the first direction X, the end cap 213 is located on the side of the first protrusion 2124a facing the opening 2121. At least a portion of the electrode assembly 22 is located on the side of the first protrusion 2124a away from the opening 2121. The body region 231 of the first current collector 23 is located at the end of the electrode assembly 22 facing the end cap 213. The second connection region 232 of the first current collector 23 is welded to the first protrusion 2124a to form a connection portion 24. A portion of the first protrusion 2124a forms the first connection region 2112, and another portion of the first protrusion 2124a forms a part of the body region 2111.

[0221] The first protrusion 2124a is a convex structure formed on the side of the sidewall 2124 facing the receiving cavity 2122. In this embodiment, along the first direction X, the end cap 213 and the electrode assembly 22 are located on both sides of the first protrusion 2124a, that is, the first protrusion 2124a is located between the electrode assembly 22 and the end cap 213 in the first direction X. Of course, in other embodiments, the main body 221 of the electrode assembly 22 may be located on the side of the first protrusion 2124a away from the opening 2121, and the first tab 222 of the electrode assembly 22 may be inserted into the inner circumferential side of the first protrusion 2124a.

[0222] The second connection area 232 of the first current collector 23 is located at one end of the electrode assembly 22 facing the end cap 213, that is, the second connection area 232 of the first current collector 23 is located between the electrode assembly 22 and the end cap 213 in the first direction X. In the embodiment of this application, the second connection area 232 of the first current collector 23 is located on the side of the body area 231 facing the end cap 213 in the first direction X.

[0223] A portion of the first protrusion 2124a forms the first connecting region 2112, and another portion of the first protrusion 2124a forms a part of the main body region 2111. That is, the structure of the first connecting region 2112 formed on the first protrusion 2124a makes a local area of ​​the first protrusion 2124a form the first connecting region 2112.

[0224] In this embodiment, the sidewall 2124 of the housing 212 is a wall portion 211. A first protrusion 2124a is formed on the side of the sidewall 2124 facing the receiving cavity 2122, and the end cap 213 is located on the side of the first protrusion 2124a facing the opening 2121. At least a portion of the electrode assembly 22 is located on the side of the first protrusion 2124a facing away from the opening 2121. The second connection area 232 of the first current collector 23 is configured to be welded to the first protrusion 2124a of the sidewall 2124 to form a connection portion 24. The first connection area 2112 is formed on the first protrusion 2124a. The cylindrical battery cell 20 with this structure can, on the one hand, limit or position the electrode assembly 22 and the end cap 213 through the first protrusion 2124a, which helps to reduce the assembly difficulty of the cylindrical battery cell 20. On the other hand, it can effectively reduce the difficulty of welding the second connection area 232 of the first current collector 23 to the side wall 2124, thereby reducing the assembly difficulty of the second connection area 232 of the first current collector 23 to the wall 211.

[0225] According to some embodiments of this application, referring to FIG6, the first protrusion 2124a is an annular structure extending circumferentially along the sidewall 2124.

[0226] In this embodiment, by setting the first protrusion 2124a as an annular structure extending circumferentially along the sidewall 2124, the limiting or positioning effect of the first protrusion 2124a on the electrode assembly 22 and the end cap 213 can be further improved. On the other hand, it can be realized that the first protrusion 2124a can be welded to the second connection area 232 of the first current collector 23 at any position in the circumferential direction of the sidewall 2124. This facilitates the welding connection between the second connection area 232 of the first current collector 23 and the first protrusion 2124a. After the first current collector 23 is assembled into the housing 212, the welding assembly of the second connection area 232 of the first current collector 23 and the first protrusion 2124a can be achieved without rotating and adjusting the position and positioning of the first current collector 23. This helps to further reduce the welding difficulty between the second connection area 232 of the first current collector 23 and the first protrusion 2124a, thereby effectively improving the assembly efficiency of the cylindrical battery cell 20.

[0227] In some embodiments, the first protrusion 2124a is formed with a plurality of first connection areas 2112, the plurality of first connection areas 2112 are arranged at circumferential intervals along the sidewall 2124, and each first connection area 2112 is connected to a connection portion 24.

[0228] The first protrusion 2124a has multiple first connecting areas 2112, and each first connecting area 2112 is connected to a connecting part 24. That is, the first protrusion 2124a is welded to the first current collecting member 23 at multiple positions in the circumferential direction of the sidewall 2124, so that the first current collecting member 23 and the first protrusion 2124a are welded together to form multiple connecting parts 24, and each connecting part 24 is connected to the main body area 2111 through a first connecting area 2112. In this embodiment, the first current collecting member 23 is provided with multiple second connecting areas 232, and the multiple second connecting areas 232 are welded to the first protrusion 2124a to form multiple connecting parts 24. It should be noted that each second connecting area 232 may be welded to the first protrusion 2124a to form multiple connecting parts 24, or each second connecting area 232 may be welded to the first protrusion 2124a to form only one connecting part 24.

[0229] Multiple first connection areas 2112 are arranged at intervals along the circumference of the sidewall 2124. Correspondingly, multiple connection parts 24 formed by welding the first current collector 23 and the first protrusion 2124a are also arranged at intervals along the circumference of the sidewall 2124. Correspondingly, multiple second connection areas 232 are also arranged at intervals along the circumference of the sidewall 2124.

[0230] In this embodiment, a plurality of first connection regions 2112 are formed on the first protrusion 2124a, which are circumferentially spaced along the sidewall 2124. Each first connection region 2112 is connected to a corresponding connection part 24, so that the first current collector 23 and the first protrusion 2124a are welded together to form a plurality of connection parts 24 circumferentially spaced along the sidewall 2124. Each connection part 24 is connected to the main body region 2111 through a first connection region 2112. This can further improve the connection stability and reliability between the first current collector 23 and the wall part 211, which is conducive to further alleviating the phenomenon of weld detachment between the first current collector 23 and the wall part 211. On the other hand, it can increase the flow area between the first current collector 23 and the wall part 211 to improve the flow capacity between the first current collector 23 and the wall part 211.

[0231] According to some embodiments of this application, as shown in Figures 4 and 6, a first groove 2124b is formed on the side of the sidewall 2124 away from the receiving cavity 2122 and corresponding to the position of the first protrusion 2124a.

[0232] For example, the first protrusion 2124a formed on the side of the sidewall 2124 facing the receiving cavity 2122 is a structure formed by a stamping process, so that the first protrusion 2124a is formed on the side of the sidewall 2124 facing the receiving cavity 2122, and a first groove 2124b is formed on the side of the sidewall 2124 away from the receiving cavity 2122 at a position corresponding to the first protrusion 2124a. Of course, the forming method of the first protrusion 2124a formed on the side of the sidewall 2124 facing the receiving cavity 2122 is not limited to this. In other embodiments, the first protrusion 2124a formed on the side of the sidewall 2124 facing the receiving cavity 2122 can also be formed by a processing process such as casting.

[0233] It should be noted that in the embodiment where the first protrusion 2124a is an annular structure extending circumferentially along the sidewall 2124, correspondingly, the first groove 2124b is also an annular groove structure extending circumferentially along the sidewall 2124.

[0234] In this embodiment, by forming a first groove 2124b on the side of the sidewall 2124 facing away from the receiving cavity 2122 and at a position corresponding to the first protrusion 2124a, the first protrusion 2124a formed on the side of the sidewall 2124 facing the receiving cavity 2122 can be formed by stamping. This allows for the formation of the first protrusion 2124a on the side of the sidewall 2124 facing the receiving cavity 2122, and the formation of the first groove 2124b on the other side at a position corresponding to the first protrusion 2124a. This structure in the cylindrical battery cell 20 reduces the difficulty of forming the first protrusion 2124a on the sidewall 2124 facing the receiving cavity 2122, thus improving the cylindrical... On the one hand, it improves the production efficiency of the battery cell 20, and on the other hand, it enables the first protrusion 2124a to have a hollow internal structure, thereby reducing the power required for welding the first protrusion 2124a and the second connection area 232 of the first current collector 23. This helps to reduce the welding difficulty between the first protrusion 2124a and the second connection area 232 of the first current collector 23, and also enables the first protrusion 2124a to have the ability to deform elastically. This helps to further alleviate the rigid tension between the second connection area 232 of the first current collector 23 and the first protrusion 2124a, thereby reducing the risk of weld detachment between the second connection area 232 of the first current collector 23 and the first protrusion 2124a.

[0235] According to some embodiments of this application, referring to FIG6, the wall thickness of a portion of the first protrusion 2124a is less than the wall thickness of other portions of the first protrusion 2124a. That is, the first protrusion 2124a is a structure with locally thinned regions, and similarly, the groove wall of the first groove 2124b is a structure with locally thinned regions.

[0236] In this embodiment, by setting the wall thickness of a portion of the first protrusion 2124a to be less than the wall thickness of other portions of the first protrusion 2124a, the first protrusion 2124a is locally thinned and forms a thinned region, thereby improving the elastic deformation capability of the first protrusion 2124a. This helps to further alleviate the rigid tension between the second connection area 232 of the first current collector 23 and the first protrusion 2124a, thereby reducing the risk of weld detachment between the second connection area 232 of the first current collector 23 and the first protrusion 2124a.

[0237] According to some embodiments of this application, please continue to refer to FIG6, the thickness of the first connection area 2112 is less than the wall thickness of the area of ​​the sidewall 2124 where the first protrusion 2124a is not formed. That is, the thickness of the first connection area 2112 is less than the wall thickness of the area of ​​the sidewall 2124 where the first groove 2124b is not provided.

[0238] For example, in FIG6, the second connection area 232 is located on the side of the first protrusion 2124a facing the opening 2121 in the first direction X and is welded to the first protrusion 2124a, such that the first connection area 2112 is formed on the side of the first protrusion 2124a facing the opening 2121. Correspondingly, the thickness of the first connection area 2112 in the first direction X is less than the wall thickness of the area of ​​the sidewall 2124 where the first protrusion 2124a is not formed.

[0239] In this embodiment, by setting the thickness of the first connecting area 2112 to be less than the wall thickness of the area of ​​the sidewall 2124 where the first protrusion 2124a is not formed, the structural strength of the sidewall 2124 is improved, and the buffering effect of the first connecting area 2112 between the connecting part 24 and the main body area 2111 is further improved. This further alleviates the rigid tension between the second connecting area 232 and the wall part 211 of the first current collector 23, which is beneficial to further reduce the phenomenon of weld detachment between the second connecting area 232 and the wall part 211 of the first current collector 23.

[0240] According to some embodiments of this application, referring to Figures 5 and 6, along the first direction X, the second connection area 232 is located on the side of the first protrusion 2124a facing the end cover 213, and the second connection area 232 is welded to the side of the first protrusion 2124a facing the end cover 213 to form a connection portion 24.

[0241] Along the first direction X, the second connection area 232 is located on the side of the first protrusion 2124a facing the end cap 213. That is, the area of ​​the first current collector 23 used for welding the first protrusion 2124a is located on the side of the first protrusion 2124a facing the end cap 213 in the first direction X, so that the electrode assembly 22 and the second connection area 232 are located on both sides of the first protrusion 2124a in the first direction X.

[0242] The second connection area 232 is welded to the side of the first protrusion 2124a facing the end cover 213 to form a connection part 24. That is, the second connection area 232 of the first current collector 23 is a structure that is welded to the side of the first protrusion 2124a facing the end cover 213.

[0243] In this embodiment, the electrode assembly 22 is located on the side of the first protrusion 2124a facing away from the end cap 213 in the first direction X. The first current collector 23 is connected to the first tab 222 of the electrode assembly 22, and the second connection area 232 of the first current collector 23 is located on the side of the first protrusion 2124a facing the end cap 213 in the first direction X and is welded to the side of the first protrusion 2124a facing the end cap 213. The cylindrical battery cell 20 with this structure can achieve the first current collector 23 and the first protrusion 2124a sharing part of the space in the first direction X, which is beneficial to improving the cylindrical shape. The internal space utilization of the battery cell 20 is improved to enhance the energy density of the cylindrical battery cell 20. On the other hand, the second connection area 232 of the first current collector 23 is located on the side of the first protrusion 2124a facing the opening 2121 of the housing 212 in the first direction X and is welded to the surface of the first protrusion 2124a facing the opening 2121. This allows the first protrusion 2124a and the second connection area 232 to be welded together from the opening 2121 of the housing 212, which is beneficial to optimizing the manufacturing process of the cylindrical battery cell 20 and reducing the assembly difficulty of the cylindrical battery cell 20.

[0244] Of course, the structure of the cylindrical battery cell 20 is not limited to this. In some embodiments, the cylindrical battery cell 20 can also have other structures. Referring to Figures 7 and 8, Figure 7 is a cross-sectional view of the cylindrical battery cell 20 provided in some embodiments of this application, and Figure 8 is a partial enlarged view of point B of the cylindrical battery cell 20 shown in Figure 7. Along the first direction X, the second connecting area 232 is located on the side of the first protrusion 2124a away from the end cover 213, and the second connecting area 232 is welded to the side of the first protrusion 2124a away from the end cover 213 to form a connecting portion 24.

[0245] Along the first direction X, the second connection area 232 is located on the side of the first protrusion 2124a away from the end cover 213. That is, the area of ​​the first current collector 23 used for welding the first protrusion 2124a is located on the side of the first protrusion 2124a away from the end cover 213 in the first direction X, so that the electrode assembly 22 and the second connection area 232 are located on the same side of the first protrusion 2124a in the first direction X.

[0246] The second connection area 232 is welded to the side of the first protrusion 2124a away from the end cover 213 to form a connection part 24. That is, the second connection area 232 of the first current collector 23 is a structure that is welded to the side of the first protrusion 2124a away from the end cover 213.

[0247] In this embodiment, by setting the second connection area 232 of the first current collector 23 to be located on the side of the first protrusion 2124a away from the end cap 213 in the first direction X and welding it to the side of the first protrusion 2124a away from the end cap 213, the second connection area 232 of the first current collector 23 and the electrode assembly 22 are both located on the side of the first protrusion 2124a away from the end cap 213. This helps to reduce the assembly difficulty of the first current collector 23 and the electrode assembly 22. In addition, the first protrusion 2124a can also play a certain limiting and positioning role for the first current collector 23.

[0248] According to some embodiments of this application, referring to Figures 6 and 8, and further referring to Figures 9 and 10, Figure 9 is a structural schematic diagram of the first current collector 23 provided in some embodiments of this application, and Figure 10 is a front view of the first current collector 23 provided in some embodiments of this application in the first direction X. The first current collector 23 includes a body region 231, a second connecting region 232, and a transition region 233. The body region 231 is disposed along the first direction X on the side of the electrode assembly 22 facing the end cap 213 and connected to the first electrode tab 222. The second connecting region 232 is located along the first direction X on the side of the body region 231 facing the end cap 213, and the second connecting region 232 is spaced apart from the body region 231. The second connecting region 232 is welded to the first protrusion 2124a to form a connecting portion 24. The transition region 233 connects the body region 231 and the second connecting region 232, and the transition region 233 is configured to deform when the body region 231 and the second connecting region 232 move closer or further apart along the first direction X.

[0249] The transition zone 233 is a structure connecting the main body region 231 and the second connecting region 232. The transition zone 233 is configured to deform when the main body region 231 and the second connecting region 232 move closer or further away from each other along the first direction X. That is, when the first current collector 23 is compressed or stretched in the first direction X, the transition zone 233 can deform when the main body region 231 and the second connecting region 232 move closer or further away from each other. It should be noted that the deformation of the transition zone 233 can be either elastic or plastic.

[0250] Optionally, in Figure 9, the first current collection component 23 is provided with a plurality of second connection areas 232 and a plurality of transition areas 233. The plurality of transition areas 233 are arranged circumferentially along the sidewall 2124 and are all connected to the main body area 231. Correspondingly, the plurality of second connection areas 232 are arranged circumferentially along the sidewall 2124. Each second connection area 232 is connected to the main body area 231 through a transition area 233. Each second connection area 232 is welded to the first protrusion 2124a to form a connection part 24. It should be noted that the connection part 24 formed by welding each second connection area 232 to the first protrusion 2124a can be one or more.

[0251] For example, the second connection area 232 is an arc-shaped structure extending circumferentially along the side wall 2124. When there are multiple connection portions 24 formed by welding each second connection area 232 to the first protrusion 2124a, the multiple connection portions 24 on the same second connection area 232 are arranged circumferentially on the second connection area 232 at intervals.

[0252] For example, in FIG10, the first current collector 23 is provided with four second connection areas 232 and four transition areas 233, and each second connection area 232 is connected to the main body area 231 through a transition area 233. Of course, in other embodiments, the number of second connection areas 232 of the first current collector 23 may also be two, three, five or six, etc.

[0253] Optionally, the body area 231, the second connecting area 232, and the transition area 233 of the first current collector 23 can be an integrally formed structure or a separate but connected structure. For example, in FIG9, the body area 231, the second connecting area 232, and the transition area 233 of the first current collector 23 are an integral structure formed by integral forming processes such as stamping and cutting.

[0254] In this embodiment, the first current collector 23 is provided with a body region 231, a second connecting region 232, and a transition region 233. The body region 231 and the second connecting region 232 are respectively connected to the first electrode 222 and the first protrusion 2124a, and the transition region 233 is connected between the body region 231 and the second connecting region 232, so that the first electrode 222 is electrically connected to the wall portion 211 through the first current collector 23. The transition region 233 is configured to deform when the body region 231 and the second connecting region 232 move closer or further apart along the first direction X, thus enabling the transition region to... 233 can play a certain buffering role between the body area 231 and the second connection area 232, thereby alleviating the rigid tension between the body area 231 and the second connection area 232, between the body area 231 and the first tab 222, and between the second connection area 232 and the first protrusion 2124a during the shaking or displacement of the electrode assembly 22. This helps to further reduce the risk of connection failure between the body area 231 and the first tab 222 and between the second connection area 232 and the first protrusion 2124a, and also helps to reduce the phenomenon of the first current collector 23 being damaged by tension.

[0255] According to some embodiments of this application, as shown in FIG9, the transition region 233 is bent to form a plurality of bent segments 2331, the plurality of bent segments 2331 are connected in sequence, and the bent segments 2331 located at both ends of the plurality of bent segments 2331 are respectively connected to the body region 231 and the second connection region 232.

[0256] The transition zone 233 is bent to form multiple bent segments 2331, which are connected in sequence. In other words, the transition zone 233 is a structure with local bending, which results in the formation of multiple bent segments 2331 connected in sequence. Each pair of adjacent bent segments 2331 is set at an acute angle, a right angle, or an obtuse angle.

[0257] For example, in Figure 9, the transition region 233 is bent to form three bent segments 2331 connected in sequence, and the two bent segments 2331 located at both ends of the three bent segments 2331 are respectively connected to the body region 231 and the second connection region 232. Of course, in other embodiments, the number of bent segments 2331 formed by the bending of the transition region 233 can also be two, four, five or six, etc.

[0258] In this embodiment, by setting the transition region 233 as a structure of bending to form a plurality of sequentially connected bent segments 2331, and the bent segments 2331 at both ends of the plurality of bent segments 2331 being connected to the body region 231 and the second connecting region 232 respectively, the deformation capability of the transition region 233 when the body region 231 and the second connecting region 232 move closer or further away from each other along the first direction X can be increased, thereby further improving the buffering effect of the transition region 233 between the body region 231 and the second connecting region 232, and further reducing the phenomenon of rigid tension between the body region 231 and the second connecting region 232, between the body region 231 and the first tab 222, and between the second connecting region 232 and the first protrusion 2124a.

[0259] According to some embodiments of this application, as shown in Figures 6, 9 and 10, a pressure relief component is provided on the end cap 213, which is configured to release the internal pressure of the cylindrical battery cell 20.

[0260] For example, the pressure relief component and the end cap 213 are integrally formed, that is, the pressure relief component is part of the end cap 213.

[0261] In this embodiment, by providing a pressure relief component for releasing the internal pressure of the cylindrical battery cell 20 in the end cap 213, the cylindrical battery cell 20 can still be depressurized through the pressure relief component when thermal runaway occurs, which helps to reduce the risk of explosion of the cylindrical battery cell 20 during use and improves the reliability of the cylindrical battery cell 20.

[0262] According to some embodiments of this application, referring to Figures 6 and 10, in a projection plane perpendicular to the first direction X, the orthographic projection of the body region 231 and the orthographic projection of the second connection region 232 form an exhaust gap 234 in the radial direction of the cylindrical battery cell 20. That is, in a projection plane perpendicular to the first direction X, the orthographic projection of the second connection region 232 and the orthographic projection of the body region 231 are spaced apart in the radial direction of the cylindrical battery cell 20.

[0263] In this embodiment, in the projection plane perpendicular to the first direction X, by setting the orthographic projection of the second connection area 232 and the orthographic projection of the body area 231 to form an exhaust gap 234 in the radial direction of the cylindrical battery cell 20, the thermal runaway gas inside the cylindrical battery cell 20 can enter the side of the first current collector 23 facing the end cap 213 through the exhaust gap 234 between the second connection area 232 and the body area 231 and then be released through the pressure relief component. This helps to reduce the obstruction of the exhaust path inside the cylindrical battery cell 20 by the first current collector 23, thereby improving the smoothness of the internal exhaust and the pressure relief rate of the cylindrical battery cell 20.

[0264] In some embodiments, as shown in FIG6 and FIG10, the pressure relief component is provided with a pressure relief groove 2133, at least a portion of the projection of the pressure relief groove 2133 in the first direction X is located within the exhaust gap 234.

[0265] In the embodiment where the pressure relief component and the end cap 213 are integrally formed, the pressure relief groove 2133 is a structure provided on the end cap 213. At least a portion of the projection of the pressure relief groove 2133 in the first direction X is located within the exhaust gap 234. That is, at least a portion of the area of ​​the end cap 213 where the pressure relief groove 2133 is provided is a structure provided in the first direction X corresponding to the exhaust gap 234 between the second connecting area 232 and the body area 231.

[0266] In this embodiment, by setting the pressure relief groove 2133 on the pressure relief component to a structure in which at least a portion of its projection in the first direction X is located within the exhaust gap 234, the pressure relief groove 2133 is configured such that at least a portion in the first direction X corresponds to the exhaust gap 234 between the second connection area 232 and the body area 231. This further improves the smoothness of internal exhaust and pressure relief of the cylindrical battery cell 20, thereby increasing the pressure relief rate of the cylindrical battery cell 20. This reduces the risk of fire and explosion caused by untimely pressure relief of the cylindrical battery cell 20, thus improving the reliability of the cylindrical battery cell 20.

[0267] According to some embodiments of this application, referring to Figures 9 and 10, in a projection plane perpendicular to the first direction X, the orthographic projection of the second connection region 232 extends circumferentially along the cylindrical battery cell 20 and is located on the periphery of the orthographic projection of the body region 231. The orthographic projection of the second connection region 232 and the orthographic projection of the body region 231 are arranged at intervals in the radial direction of the cylindrical battery cell 20. The diameter of the orthographic projection of the outer edge of the second connection region 232 is D1, and the orthographic projection of the transition region 233 extends radially along the cylindrical battery cell 20 with a length of L2, satisfying that 1 / 15≤L2 / D1≤1 / 3.

[0268] In the projection plane perpendicular to the first direction X, the orthographic projection of the second connection area 232 extends circumferentially along the cylindrical battery cell 20 and is located around the orthographic projection of the body area 231. That is, the orthographic projection of the second connection area 232 in the first direction X is an arc-shaped or ring-shaped structure extending circumferentially along the cylindrical battery cell 20, and the second connection area 232 is arranged around the body area 231. For example, in Figure 10, the first current collector 23 is provided with multiple second connection areas 232, each connected to the body area 231 via a transition area 233. The multiple second connection areas 232 are arranged at intervals circumferentially along the cylindrical battery cell 20 and surround the body area 231, and each second connection area 232 is an arc-shaped structure extending circumferentially along the cylindrical battery cell 20. Correspondingly, in the projection plane perpendicular to the first direction X, the diameter D1 of the orthographic projection of the outer edge of the second connection area 232 is the diameter of the circle containing the orthographic projection of the outer edge of the second connection area 232.

[0269] In a projection plane perpendicular to the first direction X, the orthographic projections of the second connecting region 232 and the main body region 231 are arranged radially spaced on the cylindrical battery cell 20, and the orthographic projection of the transition region 233 extends radially along the cylindrical battery cell 20. That is, the orthographic projections of the second connecting region 232 and the main body region 231 in the first direction X are arranged radially spaced on the cylindrical battery cell 20, and the transition region 233 connects the second connecting region 232 and the main body region 231 radially along the cylindrical battery cell 20.

[0270] Optionally, in a projection plane perpendicular to the first direction X, the ratio of the length L2 of the orthographic projection of the transition region 233 onto the radial direction of the cylindrical battery cell 20 to the diameter D1 of the orthographic projection of the outer edge of the second connection region 232 can be 1 / 15, 0.07, 0.08, 0.09, 0.1, 0.11, 0.12, 0.13, 1 / 7, 0.15, 0.16, 0.18, 0.2, 0.22, 0.23, 0.25, 0.26, 0.28, 0.3, 0.31, 0.32, or 1 / 3, etc.

[0271] In this embodiment, in the projection plane perpendicular to the first direction X, the orthographic projections of the second connecting region 232 and the main body region 231 are arranged at intervals in the radial direction of the cylindrical battery cell 20. Furthermore, the ratio of the length of the transition region 233 of the first current collector 23 in the radial direction of the cylindrical battery cell 20 to the diameter of the orthographic projection of the outer edge of the second connecting region 232 is set to 1 / 15 to 1 / 3. This alleviates the problem of the transition region 233 occupying too small a size in the radial direction of the cylindrical battery cell 20 and helps to expand the exhaust space between the second connecting region 232 and the main body region 231. This allows the thermal runaway gas inside the cylindrical battery cell 20 to be released through the venting space between the second connecting region 232 and the body region 231 via the pressure relief component on the end cap 213. This improves the smoothness of internal venting of the cylindrical battery cell 20, thereby increasing the pressure relief rate of the cylindrical battery cell 20. This reduces the risk of the cylindrical battery cell 20 bursting or exploding due to untimely pressure relief. On the other hand, it alleviates the problem of insufficient support strength of the transition region 233 in the body region 231 and the second connecting region 232 caused by the excessive radial size occupied by the transition region 233 in the cylindrical battery cell 20. This effectively improves the support effect of the first current collector 23 on the electrode assembly 22 and its resistance to the expansion of the electrode assembly 22 during use, thus alleviating the phenomenon of excessive expansion or displacement of the electrode assembly 22. This, in turn, helps to improve the stability and reliability of the cylindrical battery cell 20 in use.

[0272] In some embodiments, as shown in Figure 10, 1 / 7 ≤ L2 / D1 ≤ 1 / 4.

[0273] In this embodiment, within the projection plane perpendicular to the first direction X, by further setting the ratio of the length of the transition region 233 of the first current collector 23 in the radial direction of the cylindrical battery cell 20 to the diameter of the orthographic projection of the outer edge of the second connection region 232 to 1 / 7 to 1 / 4, the phenomenon of the transition region 233 occupying too small a size in the radial direction of the cylindrical battery cell 20 can be further alleviated. This is beneficial to further expand the exhaust space between the second connection region 232 and the body region 231, so that the thermal runaway gas inside the cylindrical battery cell 20 can be released through the exhaust space between the second connection region 232 and the body region 231 and then through the pressure relief component on the end cap 213, thereby further improving the performance of the cylindrical battery cell. The smooth internal venting of the cylindrical battery cell 20 further improves the depressurization rate of the cylindrical battery cell 20, thereby reducing the risk of bursting or exploding due to untimely depressurization. On the other hand, it can further alleviate the phenomenon that the transition zone 233 occupies too large a size in the radial direction of the cylindrical battery cell 20, resulting in insufficient support strength of the transition zone 233 in the body region 231 and the second connection region 232. This can further improve the support effect of the first current collector 23 on the electrode assembly 22 and the effect of resisting the expansion of the electrode assembly 22 during use, thereby further alleviating the phenomenon of excessive expansion or displacement of the electrode assembly 22, and thus helping to further improve the stability and reliability of the cylindrical battery cell 20 in use.

[0274] In some embodiments, please continue to refer to Figure 10, 3mm≤L2≤15mm.

[0275] Optionally, in the projection plane perpendicular to the first direction X, the length L2 of the orthographic projection of the transition zone 233 onto the radial direction of the cylindrical battery cell 20 can be 3mm, 3.5mm, 4mm, 4.5mm, 5mm, 5.5mm, 6mm, 6.5mm, 7mm, 7.5mm, 8mm, 8.5mm, 9mm, 9.5mm, 10mm, 10.5mm, 11mm, 11.5mm, 12mm, 12.5mm, 13mm, 13.5mm, 14mm, 14.5mm, or 15mm, etc.

[0276] In this embodiment, in the projection plane perpendicular to the first direction X, by setting the length of the transition region 233 of the first current collector 23 in the radial direction of the cylindrical battery cell 20 to 3mm to 15mm, on the one hand, setting the length of the transition region 233 in the radial direction of the cylindrical battery cell 20 to be greater than or equal to 3mm can increase the exhaust space between the second connection region 232 and the body region 231, so that the thermal runaway gas inside the cylindrical battery cell 20 can pass through the exhaust space between the second connection region 232 and the body region 231 and then through the vent on the end cap 213. The pressure component is released, which helps to improve the smoothness of internal venting of the cylindrical battery cell 20. On the other hand, setting the length of the transition zone 233 in the radial direction of the cylindrical battery cell 20 to less than or equal to 15mm can alleviate the phenomenon that the transition zone 233 is too long and therefore the support strength of the transition zone 233 in the body area 231 and the second connection area 232 is insufficient. This helps to improve the support effect of the first current collector 23 on the electrode assembly 22 and the effect of resisting the expansion of the electrode assembly 22 during use, so as to further alleviate the phenomenon of excessive expansion or displacement of the electrode assembly 22.

[0277] According to some embodiments of this application, and in conjunction with Figures 6 and 10, the thickness of the transition region 233 is T1, and the width of the orthographic projection of the transition region 233 in the direction perpendicular to its extension direction in the projection plane perpendicular to the first direction X is W, satisfying 0.3mm. 2 ≤W×T1≤8mm 2 .

[0278] Wherein, the thickness of the transition region 233 is T1, which is the thickness of the transition region 233 at any position. In an embodiment where the transition region 233 includes a plurality of sequentially connected bending segments 2331, the thickness of each bending segment 2331 is T1.

[0279] Optionally, the product of W and T1 can be 0.3 mm. 2 0.4mm 2 0.5mm 2 0.6mm 2 0.7mm 2 0.8mm 2 0.9mm 2 1mm 2 1.5mm 2 2mm 2 2.5mm 2 3mm 2 3.5mm 2 4mm 2 4.5mm 2 5mm 2 5.5mm 2 6mm 26.5mm 2 7mm 2 7.5mm 2 Or 8mm 2 wait.

[0280] In this embodiment, the product of W and T1 is set to 0.3mm. 2 up to 8mm 2 On the one hand, the product of W and T1 is set to be less than or equal to 8mm. 2 This design can alleviate the problem of excessive deformation difficulty in the transition region 233 caused by excessively large W and T1 values. This improves the ability of the transition region 233 to deform when the body region 231 and the second connecting region 232 move closer or further apart along the first direction X. This allows the transition region 233 to act as a better buffer between the body region 231 and the second connecting region 232. Consequently, it reduces rigid tension between the body region 231 and the second connecting region 232, between the body region 231 and the first tab 222, and between the second connecting region 232 and the first protrusion 2124a during periods of shaking or displacement of the electrode assembly 22. Furthermore, the product of W and T1 is set to be greater than or equal to 0.3 mm. 2 It can improve the structural strength of the transition zone 233, which helps to alleviate the phenomenon of insufficient support strength of the transition zone 233 between the body zone 231 and the second connection zone 232, so as to improve the support effect of the first current collector 23 on the electrode assembly 22 and the effect of resisting the expansion of the electrode assembly 22 during use. It can also improve the flow capacity of the transition zone 233, which helps to improve the flow guiding effect and flow guiding requirements of the first current collector 23.

[0281] According to some embodiments of this application, referring to Figures 9 and 10, in a projection plane perpendicular to the first direction X, the width of the orthographic projection of the transition region 233 in the direction perpendicular to its extension direction is W, which satisfies 2mm≤W≤10mm.

[0282] Optionally, the width W of the projection of the transition zone 233 in the first direction X can be 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, 5mm, 5.5mm, 6mm, 6.5mm, 7mm, 7.5mm, 8mm, 8.5mm, 9mm, 9.5mm or 10mm, etc.

[0283] In this embodiment, by setting the width of the projection of the transition region 233 of the first current collector 23 in the first direction X to 2mm to 10mm, on the one hand, setting the width of the projection of the transition region 233 in the first direction X to be greater than or equal to 2mm can improve the flow capacity of the transition region 233, thereby improving the flow guiding effect of the first current collector 23, and on the other hand, it can improve the structural strength of the transition region 233, which helps to alleviate the phenomenon of insufficient support strength of the transition region 233 in the body region 231 and the second connection region 232, thereby improving the support effect of the first current collector 23 on the electrode assembly 22 and the resistance to the expansion of the electrode assembly 22 during use. On the other hand, setting the width of the projection of the transition region 233 in the first direction X to be less than or equal to 10 mm can effectively improve the ability of the transition region 233 to deform when the body region 231 and the second connection region 232 move closer or further apart along the first direction X. This allows the transition region 233 to play a better buffering role between the body region 231 and the second connection region 232, thereby reducing the rigid pulling phenomenon between the body region 231 and the second connection region 232, between the body region 231 and the first tab 222, and between the second connection region 232 and the first protrusion 2124a during the process of the electrode assembly 22 shaking or shifting.

[0284] In some embodiments, as shown in Figure 10, 3mm ≤ W ≤ 5mm.

[0285] In this embodiment, by further setting the width of the projection of the transition region 233 of the first current collector 23 in the first direction X to 3mm to 5mm, on the one hand, setting the width of the projection of the transition region 233 in the first direction X to be greater than or equal to 3mm can further improve the flow capacity of the transition region 233, thereby further improving the flow guiding effect of the first current collector 23, and on the other hand, it can further improve the structural strength of the transition region 233, which is beneficial to further alleviate the phenomenon of insufficient support strength of the transition region 233 in the body region 231 and the second connection region 232, thereby further improving the support effect of the first current collector 23 on the electrode assembly 22 and its resistance to the electrode assembly 22. In addition to the expansion effect during use, setting the width of the projection of the transition area 233 in the first direction X to be less than or equal to 5mm can further enhance the ability of the transition area 233 to deform when the body area 231 and the second connection area 232 move closer or further apart along the first direction X, thereby improving the buffering effect of the transition area 233 between the body area 231 and the second connection area 232. This can further reduce the rigid pulling phenomenon between the body area 231 and the second connection area 232, between the body area 231 and the first tab 222, and between the second connection area 232 and the first protrusion 2124a during the process of the electrode assembly 22 shaking or shifting.

[0286] According to some embodiments of this application, as shown in Figures 6 and 9, the thickness of the transition region 233 is T1, which satisfies 0.15mm≤T1≤0.8mm.

[0287] Optionally, the thickness T1 of the transition zone 233 can be 0.15mm, 0.2mm, 0.25mm, 0.3mm, 0.35mm, 0.4mm, 0.45mm, 0.5mm, 0.55mm, 0.6mm, 0.65mm, 0.7mm, 0.75mm or 0.8mm, etc.

[0288] In this embodiment, by setting the thickness of the transition region 233 of the first current collector 23 to 0.15mm to 0.8mm, on the one hand, setting the thickness of the transition region 233 to be greater than or equal to 0.15mm can improve the flow capacity of the transition region 233, thereby improving the flow guiding effect of the first current collector 23, and can also improve the structural strength of the transition region 233. This helps to alleviate the phenomenon of insufficient support strength of the transition region 233 in the body region 231 and the second connection region 232, thereby improving the support effect of the first current collector 23 on the electrode assembly 22 and the effect of resisting the expansion of the electrode assembly 22 during use. On the other hand, setting the thickness of the transition region 233 to be less than or equal to 0.8mm can improve the flow guiding effect of the first current collector 23. The 0.8mm thickness effectively enhances the ability of the transition region 233 to deform when the body region 231 and the second connection region 232 move closer or further apart along the first direction X. This allows the transition region 233 to act as a better buffer between the body region 231 and the second connection region 232, thereby reducing rigid tension between the body region 231 and the second connection region 232, between the body region 231 and the first tab 222, and between the second connection region 232 and the first protrusion 2124a during the shaking or displacement of the electrode assembly 22. It also saves the space occupied by the transition region 233 in the first direction X, which is beneficial to improving the internal space utilization of the cylindrical battery cell 20.

[0289] In some embodiments, please continue to refer to Figures 6 and 9, 0.3mm≤T1≤0.5mm.

[0290] In this embodiment, by further setting the thickness of the transition region 233 of the first current collector 23 to 0.3mm to 0.5mm, on the one hand, setting the thickness of the transition region 233 to be greater than or equal to 0.3mm can further improve the flow capacity of the transition region 233, thereby further improving the flow guiding effect of the first current collector 23, and can further improve the structural strength of the transition region 233. This helps to further alleviate the phenomenon of insufficient support strength of the transition region 233 in the body region 231 and the second connection region 232, thereby further improving the support effect of the first current collector 23 on the electrode assembly 22 and the effect of resisting the expansion of the electrode assembly 22 during use. On the other hand, setting the thickness of the transition region 233 to less than 0.3mm can further improve the flow guiding effect of the first current collector 23. A thickness of 0.5 mm or more can further enhance the ability of the transition region 233 to deform when the body region 231 and the second connection region 232 move closer or further apart along the first direction X. This can further enhance the buffering effect of the transition region 233 between the body region 231 and the second connection region 232. As a result, during the process of the electrode assembly 22 shaking or shifting, it can further reduce the rigid pulling phenomenon between the body region 231 and the second connection region 232, between the body region 231 and the first tab 222, and between the second connection region 232 and the first protrusion 2124a. It can also further save the space occupied by the transition region 233 in the first direction X, which is conducive to further improving the internal space utilization of the cylindrical battery cell 20.

[0291] According to some embodiments of this application, as shown in Figures 6 and 9, the thickness of the transition region 233 is less than the thickness of the body region 231.

[0292] In this embodiment, by setting the thickness of the transition region 233 to be less than the thickness of the main body region 231, the manufacturing cost and manufacturing difficulty of the first current collection component 23 are reduced, while the ability of the transition region 233 to deform when the main body region 231 and the second connecting region 232 move closer or further apart along the first direction X is improved, so that the transition region 233 can play a better buffering role between the main body region 231 and the second connecting region 232.

[0293] According to some embodiments of this application, please continue to refer to Figures 6 and 9, the thickness of the transition region 233 is less than the thickness of the second connection region 232.

[0294] In this embodiment, by setting the thickness of the transition region 233 to be less than the thickness of the second connection region 232, the manufacturing cost and manufacturing difficulty of the first current collector 23 are reduced, while the ability of the transition region 233 to deform when the body region 231 and the second connection region 232 move closer or further apart along the first direction X is improved, so that the transition region 233 can play a better buffering role between the body region 231 and the second connection region 232.

[0295] According to some embodiments of this application, referring to Figures 6 and 8, the sidewall 2124 is bent at one end away from the bottom wall 2123 in the first direction X to form a flange 2124c, which encloses an opening 2121. Along the first direction X, a portion of the end cap 213 is located between the flange 2124c and the first protrusion 2124a, which are configured to engage and clamp the end cap 213.

[0296] The flange 2124c is a flange structure formed by bending one end of the side wall 2124 away from the bottom wall 2123 in the first direction X towards the side closer to the receiving cavity 2122. The flange 2124c surrounds and forms an opening 2121, that is, the flange 2124c is an annular structure, so that the opening 2121 is formed on the inner circumference of the flange 2124c.

[0297] In this embodiment, the outer edge of the end cap 213 extends between the flange 2124c and the first protrusion 2124a, so that the flange 2124c and the first protrusion 2124a can cooperate to clamp and assemble a portion of the end cap 213, thereby realizing the assembly connection between the end cap 213 and the housing 212.

[0298] In this embodiment, a flange 2124c is formed by bending one end of the side wall 2124 away from the bottom wall 2123 along the first direction X, and a portion of the end cap 213 is positioned between the first protrusion 2124a and the flange 2124c in the first direction X. This allows the first protrusion 2124a and the flange 2124c to also serve to assemble and fix the end cap 213, thereby achieving the assembly between the end cap 213 and the housing 212. The cylindrical battery cell 20 with this structure can reduce the assembly difficulty between the end cap 213 and the housing 212, thereby improving the production efficiency of the cylindrical battery cell 20.

[0299] According to some embodiments of this application, referring to Figures 4, 6 and 8, the cylindrical battery cell 20 may further include a seal 27, at least a portion of which is disposed radially between the sidewall 2124 and the end cap 213 of the cylindrical battery cell 20, the seal 27 being configured to seal the end cap 213 and the sidewall 2124.

[0300] At least a portion of the seal 27 is disposed radially between the sidewall 2124 and the end cap 213 of the cylindrical battery cell 20, that is, at least a portion of the seal 27 is located between the outer peripheral surface of the end cap 213 and the inner peripheral surface of the sidewall 2124, so that the seal 27 can seal the gap between the outer peripheral surface of the end cap 213 and the inner peripheral surface of the sidewall 2124.

[0301] Optionally, the seal 27 is made of an insulating material, so that the seal 27 can also serve as an insulating barrier between the end cap 213 and the side wall 2124. For example, the material of the seal 27 can be rubber, silicone or plastic, etc.

[0302] In this embodiment, the cylindrical battery cell 20 is also provided with a sealing element 27. By disposing at least a portion of the sealing element 27 radially between the side wall 2124 and the end cap 213 of the cylindrical battery cell 20, the sealing element 27 can seal the gap between the end cap 213 and the side wall 2124, thereby reducing the risk of leakage during use of the cylindrical battery cell 20 and improving the stability and reliability of the cylindrical battery cell 20.

[0303] In some embodiments, referring to Figures 6 and 8, a portion of the seal 27 is disposed between the end cap 213 and the first protrusion 2124a along the first direction X. That is, a portion of the seal 27 is located between the outer peripheral surface of the end cap 213 and the inner peripheral surface of the sidewall 2124, and the portion of the seal 27 extends between the end cap 213 and the first protrusion 2124a, such that a portion of the seal 27 is located between the end cap 213 and the first protrusion 2124a in the first direction X, so that the seal 27 can also separate the end cap 213 and the first protrusion 2124a.

[0304] It should be noted that in the embodiment where the second connection area 232 of the first collector component 23 is located on the side of the first protrusion 2124a facing the end cap 213 and is welded to the first protrusion 2124a, as shown in FIG6, a portion of the seal 27 is located between the second connection area 232 and the end cap 213, so that the seal 27 can also separate the second connection area 232 and the end cap 213.

[0305] In this embodiment, by setting a portion of the seal 27 to extend between the end cap 213 and the first protrusion 2124a, the seal 27 can also seal the gap between the end cap 213 and the first protrusion 2124a, which is beneficial to further improve the sealing effect of the seal 27 on the gap between the end cap 213 and the side wall 2124. Furthermore, the first protrusion 2124a and the end cap 213 can also play a certain clamping role on the seal 27, which is beneficial to improve the assembly stability of the seal 27.

[0306] In some embodiments, referring again to Figures 6 and 8, a portion of the seal 27 is disposed between the end cap 213 and the flange 2124c along the first direction X. That is, a portion of the seal 27 is located between the outer peripheral surface of the end cap 213 and the inner peripheral surface of the sidewall 2124, and a portion of the seal 27 extends between the end cap 213 and the flange 2124c, such that a portion of the seal 27 is located between the end cap 213 and the flange 2124c in the first direction X, so that the seal 27 can also separate the end cap 213 and the flange 2124c.

[0307] Optionally, in FIG6, the seal 27 is an annular structure surrounding the end cap 213. The seal 27 may include a first part, a second part, and a third part arranged and connected in sequence along the first direction X. The first part is located between the first protrusion 2124a and the end cap 213 in the first direction X. The second part is located between the outer peripheral surface of the end cap 213 and the inner peripheral surface of the side wall 2124. The third part is located between the flange 2124c and the end cap 213 in the first direction X.

[0308] In this embodiment, by setting a portion of the seal 27 to extend between the end cap 213 and the flange 2124c, the seal 27 can also seal the gap between the end cap 213 and the flange 2124c, which helps to further improve the sealing effect of the seal 27 on the gap between the end cap 213 and the side wall 2124. Furthermore, the flange 2124c and the end cap 213 can also play a certain clamping role on the seal 27, which helps to improve the assembly stability of the seal 27.

[0309] According to some embodiments of this application, referring to Figures 11 and 12, Figure 11 is a cross-sectional view of a cylindrical battery cell 20 provided in some embodiments of this application, and Figure 12 is a partial enlarged view of point C of the cylindrical battery cell 20 shown in Figure 11. The wall portion 211 is a sidewall 2124, the body region 231 is located at one end of the electrode assembly 22 in the first direction X, and the body region 231 is connected to the first tab 222. The second connecting region 232 extends circumferentially along the sidewall 2124 and surrounds the body region 231. The second connecting region 232 is welded to the sidewall 2124 to form a connecting portion 24. A portion of the sidewall 2124 forms the first connecting region 2112, and another portion of the sidewall 2124 forms the main body region 2111.

[0310] The second connecting region 232 extends circumferentially along the side wall 2124 and surrounds the body region 231. That is, the second connecting region 232 is a ring structure extending circumferentially along the side wall 2124, and the body region 231 is connected to the inner side of the second connecting region 232, so that the body region 231 and the second connecting region 232 form a cavity structure that surrounds at least one side of the body region 231 along the first direction X.

[0311] The second connecting area 232 is welded to the side wall 2124 to form a connecting part 24, that is, the outer peripheral surface of the second connecting area 232 and the inner peripheral surface of the side wall 2124 abut against each other and are welded together to form a connecting part 24.

[0312] In this embodiment, the sidewall 2124 of the housing 212 is a wall portion 211. By setting the body region 231 of the first current collector 23 to be located at one end of the electrode assembly 22 in the first direction X, and the body region 231 being connected to the first tab 222, and setting the second connection region 232 to be a structure surrounding the body region 231 along the circumference of the sidewall 2124, the second connection region 232 of the first current collector 23 and the sidewall 2124 are welded together, which helps to reduce the welding difficulty between the first current collector 23 and the sidewall 2124, and can increase the area of ​​the first current collector 23 for welding with the sidewall 2124, thereby improving the connection reliability between the first current collector 23 and the sidewall 2124.

[0313] In some embodiments, referring to FIG12, one end of the second connection region 232 is connected to the body region 231 along the first direction X, and the second connection region 232 extends from the body region 231 toward the end cap 213. That is, the second connection region 232 has a structure in which one end is connected to the body region 231 in the first direction X, and protrudes along the first direction X from the side of the body region 231 facing the end cap 213.

[0314] In this embodiment, by connecting one end of the second connection area 232 in the first direction X to the body area 231, and setting the second connection area 232 to extend from the body area 231 toward the end cap 213, the second connection area 232 protrudes from the side of the body area 231 facing the opening 2121 of the housing 212 in the first direction X. The cylindrical battery cell 20 with this structure is convenient for welding the second connection area 232 and the side wall 2124, which helps to reduce the welding assembly difficulty between the second connection area 232 and the side wall 2124. On the other hand, it can alleviate the phenomenon of the second connection area 232 being inserted into the electrode assembly 22 or squeezing the electrode assembly 22, which helps to reduce the risk of damage or wear to the electrode assembly 22 during use.

[0315] According to some embodiments of this application, referring to FIG13, FIG13 is a partial cross-sectional view of a cylindrical battery cell 20 provided in other embodiments of this application. The axial direction of the cylindrical battery cell 20 is a first direction X. The outer casing 21 may include a housing 212 and an end cap 213. The housing 212 includes an integrally formed side wall 2124 and a bottom wall 2123. The side wall 2124 surrounds the bottom wall 2123. Along the first direction X, one end of the side wall 2124 is connected to the bottom wall 2123, and the other end forms an opening 2121. The side wall 2124 and the bottom wall 2123 together define a receiving cavity 2122. The electrode assembly 22 is received in the receiving cavity 2122. The end cap 213 closes the opening 2121. The wall portion 211 is the end cap 213.

[0316] Among them, the wall portion 211 is the end cap 213, that is, the first current collecting member 23 is a structure that is welded to the end cap 213 to form a connecting portion 24, and the first connecting area 2112 is formed on the end cap 213.

[0317] In this embodiment, by setting the end cap 213 of the outer casing 21 as a wall portion 211, the second connection area 232 of the first current collector 23 is a structure that is welded to the end cap 213, thereby reducing the welding assembly difficulty between the second connection area 232 of the first current collector 23 and the wall portion 211, and improving the production efficiency of the cylindrical battery cell 20.

[0318] According to some embodiments of this application, referring to FIG13, along the first direction X, a second protrusion 2131 is formed on the side of the end cap 213 facing the electrode assembly 22. The second connection area 232 of the first current collector 23 is welded to the second protrusion 2131 to form a connection portion 24. A portion of the second protrusion 2131 forms the first connection area 2112, and another portion of the second protrusion 2131 forms a part of the main body area 2111.

[0319] The second protrusion 2131 is a convex hull structure formed on the side of the end cap 213 facing the electrode assembly 22 in the first direction X. Along the first direction X, the second protrusion 2131 abuts against the second connection area 232 of the first current collector 23, and the second protrusion 2131 and the second connection area 232 of the first current collector 23 are welded together to form a connection portion 24.

[0320] A portion of the second protrusion 2131 forms the first connecting region 2112, and another portion of the second protrusion 2131 forms a part of the main body region 2111. That is, the structure of the first connecting region 2112 formed on the second protrusion 2131 makes a local area of ​​the second protrusion 2131 form the first connecting region 2112.

[0321] In this embodiment, by forming a second protrusion 2131 on the side of the end cap 213 facing the electrode assembly 22, and by welding the second connection area 232 of the first current collector 23 to the second protrusion 2131 of the end cap 213 to form a connection portion 24, the first connection area 2112 is formed on the second protrusion 2131. The cylindrical battery cell 20 with this structure can improve the contact effect between the area of ​​the end cap 213 used for welding to the second connection area 232 and the second connection area 232 in the first direction X, thereby improving the welding quality between the second connection area 232 of the first current collector 23 and the end cap 213.

[0322] According to some embodiments of this application, as shown in FIG13, the second protrusion 2131 is an annular structure extending circumferentially along the sidewall 2124.

[0323] Optionally, the second protrusion 2131 may form a plurality of first connecting regions 2112, which are arranged at intervals along the circumference of the sidewall 2124. Each first connecting region 2112 is connected to a connecting part 24. That is, the second protrusion 2131 is welded to the first current collecting member 23 to form a plurality of connecting parts 24 arranged at intervals along the circumference of the sidewall 2124, and each connecting part 24 is a structure that is interconnected with the main body region 2111 through a first connecting region 2112.

[0324] In this embodiment, by setting the second protrusion 2131 as an annular structure extending circumferentially along the sidewall 2124, the second protrusion 2131 can be welded to the second connection area 232 of the first current collector 23 at any position in the circumferential direction of the sidewall 2124. This facilitates the welding connection between the second connection area 232 and the second protrusion 2131 of the first current collector 23. After the first current collector 23 is assembled into the housing 212, the welding assembly of the second connection area 232 and the second protrusion 2131 of the first current collector 23 can be achieved without rotating and adjusting the position and positioning of the first current collector 23. This effectively reduces the welding difficulty between the second connection area 232 and the second protrusion 2131 of the first current collector 23, thereby improving the assembly efficiency of the cylindrical battery cell 20.

[0325] In some embodiments, please continue to refer to FIG13, along the first direction X, the end cap 213 is formed on the side opposite to the electrode assembly 22 and at the position corresponding to the second protrusion 2131, with a second groove 2132.

[0326] For example, the second protrusion 2131 formed on the side of the end cap 213 facing the electrode assembly 22 is a structure formed by a stamping process, so that the second protrusion 2131 is formed on the side of the end cap 213 facing the electrode assembly 22, and a second groove 2132 is formed on the side of the end cap 213 facing away from the electrode assembly 22 at a position corresponding to the second protrusion 2131. Of course, the forming method of the second protrusion 2131 formed on the side of the end cap 213 facing the electrode assembly 22 is not limited to this. In other embodiments, the second protrusion 2131 formed on the side of the end cap 213 facing the electrode assembly 22 can also be formed by a processing process such as casting.

[0327] It should be noted that in the embodiment where the second protrusion 2131 is an annular structure extending circumferentially along the sidewall 2124, the second groove 2132 is also an annular groove structure extending circumferentially along the sidewall 2124.

[0328] In this embodiment, by forming a second groove 2132 on the side of the end cap 213 facing away from the electrode assembly 22 and corresponding to the second protrusion 2131, the second protrusion 2131 formed on the side of the end cap 213 facing the electrode assembly 22 can be formed by stamping. This allows the cylindrical battery cell 20 to form the second protrusion 2131 on the side of the end cap 213 facing the electrode assembly 22 and the second groove 2132 on the other side corresponding to the second protrusion 2131. This structure reduces the difficulty of forming the second protrusion 2131 on the side of the end cap 213 facing the electrode assembly 22, which is beneficial to improving the production efficiency of the cylindrical battery cell 20. On the other hand, it enables the second protrusion 2131 to have a hollow internal structure, thereby reducing the power required for welding the second protrusion 2131 and the second connection area 232 of the first current collector 23, which is beneficial to reducing the welding difficulty between the second protrusion 2131 and the second connection area 232 of the first current collector 23.

[0329] According to some embodiments of this application, as shown in Figures 4, 6, 8, 12 and 13, the electrode assembly 22 further includes a main body 221. Along the first direction X, a first tab 222 is connected to one end of the main body 221, and a second connection area 232 of the first current collector 23 is located on the side of the first tab 222 away from the main body 221 and is connected to the first tab 222.

[0330] The main body 221, the first electrode 222 and the first current collector 23 are arranged in sequence along the first direction X, and the first electrode 222 is connected between the main body 221 and the body region 231 of the first current collector 23 in the first direction X.

[0331] In this embodiment, by setting the first tab 222 to be connected to one end of the main body 221 and setting the second connection area 232 of the first current collector 23 to be on the side of the first tab 222 away from the main body 221, the main body 221, the first tab 222 and the second connection area 232 of the first current collector 23 are arranged sequentially along the first direction X, thereby reducing the assembly difficulty between the first tab 222 and the second connection area 232 of the first current collector 23, which is beneficial to improving the production efficiency of the cylindrical battery cell 20 and optimizing the production process of the cylindrical battery cell 20.

[0332] According to some embodiments of this application, the material of the first current collector 23 includes copper.

[0333] According to some embodiments of this application, as shown in FIG6, the first electrode tab 222 is welded to the body region 231 of the first current collector 23.

[0334] For example, the welding connection between the body region 231 of the first current collector 23 and the first electrode 222 can be of various types, such as laser welding or ultrasonic welding.

[0335] In this embodiment, by setting the first tab 222 and the body region 231 of the first current collector 23 as a welded connection, the reliability and robustness of the connection between the first tab 222 and the body region 231 of the first current collector 23 are improved, thereby enhancing the stability of the cylindrical battery cell 20 in use. Furthermore, the hardness of the first connecting region 2112 of the wall 211 is less than the hardness of the main body region 2111 of the wall 211, and the connecting portion 24 formed by welding the second connecting region 232 of the first current collector 23 to the wall 211 of the outer casing 21 is connected to the first connecting region 2112. That is, the second connecting region 232 of the first current collector 23 is welded to the first connecting region 2112 to form the connecting portion 24, so that the connecting portion 24 is connected to the main body region 2111 through the first connecting region 2112. This ensures that during the use of the cylindrical battery cell 20, when the first tab 222 pulls on the first current collector 23 due to the shaking of the electrode assembly 22, The first connection area 2112 can play a certain buffering role between the connection part 24 and the main body area 2111, so that the first current collector 23 can have the ability to float slightly relative to the wall 211. This can also alleviate the rigid tension between the first tab 222 and the main body area 231 of the first current collector 23, which helps to reduce the phenomenon of welding detachment between the first tab 222 and the main body area 231 of the first current collector 23. In this way, the risk of connection failure between the electrode assembly 22 and the wall 211 of the casing 21 can be further reduced during the use of the cylindrical battery cell 20, thereby improving the stability and service life of the cylindrical battery cell 20.

[0336] According to some embodiments of this application, as shown in FIG6, the wall thickness of the wall portion 211 is T2, which satisfies 0.2mm≤T2≤0.8mm.

[0337] It should be noted that 0.2mm≤T2≤0.8mm, that is, the wall thickness at any position of the wall 211 satisfies 0.2mm to 0.8mm.

[0338] For example, the wall thickness T2 of the wall portion 211 can be 0.2mm, 0.21mm, 0.22mm, 0.25mm, 0.28mm, 0.3mm, 0.35mm, 0.4mm, 0.45mm, 0.5mm, 0.55mm, 0.6mm, 0.65mm, 0.7mm, 0.75mm or 0.8mm, etc.

[0339] In this embodiment, the wall thickness of the wall portion 211 is 0.2mm to 0.8mm. On the one hand, by setting the wall thickness of the wall portion 211 to be greater than or equal to 0.2mm, it is beneficial to improve the structural strength of the wall portion 211, thereby reducing the phenomenon of deformation or cracking of the wall portion 211 during use, and reducing the risk of welding defects during welding assembly of the wall portion 211 and the second connection area 232 of the first current collector 23. On the other hand, by setting the wall thickness of the wall portion 211 to be less than or equal to 0.8mm, it is beneficial to alleviate the phenomenon of excessive weight of the cylindrical battery cell 20, and to save the amount of wall portion 211 used, thereby reducing the phenomenon of excessive material waste, which is beneficial to reduce the manufacturing cost of the cylindrical battery cell 20. Furthermore, when the wall portion 211 is welded to the second connection area 232 of the first current collector 23, the welding power required can be reduced, thereby reducing the welding assembly difficulty between the first current collector 23 and the wall portion 211.

[0340] According to some embodiments of this application, this application also provides a battery device 100, which includes a cylindrical battery cell 20 of any of the above embodiments.

[0341] As shown in Figure 2, the battery device 100 may also include a housing 10, in which cylindrical battery cells 20 are housed.

[0342] In some embodiments, the housing 10 may include a first housing body 11 and a second housing body 12, the first housing body 11 and the second housing body 12 covering each other, the first housing body 11 and the second housing body 12 together defining an assembly space for accommodating the cylindrical battery cell 20.

[0343] Optionally, the second box body 12 can be a hollow structure with one end open, and the first box body 11 can be a plate-like structure. The first box body 11 covers the open side of the second box body 12 so that the first box body 11 and the second box body 12 together define the assembly space; the first box body 11 and the second box body 12 can also be hollow structures with one side open, and the open side of the first box body 11 covers the open side of the second box body 12.

[0344] Of course, the box 10 formed by the first box body 11 and the second box body 12 can be of various shapes, such as a cylinder or a cuboid. For example, in Figure 2, the box 10 is a cuboid structure.

[0345] Optionally, the cylindrical battery cell 20 disposed within the housing 10 can be one or more. For example, in Figure 2, the housing 10 of the battery device 100 contains multiple cylindrical battery cells 20. These cells can be connected in series, parallel, or a combination thereof. A combination thereof means that some of the cylindrical battery cells 20 are connected in series and others in parallel. The multiple cylindrical battery cells 20 can be directly connected in series, parallel, or a combination thereof, and then the entire assembly of the multiple cylindrical battery cells 20 is housed within the housing 10. Alternatively, the battery device 100 can also consist of multiple cylindrical battery cells 20 first connected in series, parallel, or a combination thereof to form a battery module, and then these battery modules are connected in series, parallel, or a combination thereof to form a whole, which is then housed within the housing 10.

[0346] The battery device 100 may also include other structures. For example, the battery device 100 may also include a busbar component that connects multiple cylindrical battery cells 20 to achieve electrical connection between the multiple cylindrical battery cells 20.

[0347] It should be noted that in some embodiments, the battery device 100 may not have a housing 10. The battery device 100 includes multiple cylindrical battery cells 20, and the battery device 100 composed of multiple cylindrical battery cells 20 can be directly mounted onto the electrical device to provide power to the electrical device through the multiple cylindrical battery cells 20. That is, the housing 10 can be part of the electrical device. Taking a vehicle 1000 as an example, the housing 10 can be part of the chassis structure of the vehicle 1000. For example, a portion of the housing 10 can be at least a part of the floor of the vehicle 1000, or a portion of the housing 10 can be at least a part of the crossbeams and longitudinal beams of the vehicle 1000.

[0348] According to some embodiments of this application, this application also provides an electrical device, which includes a cylindrical battery cell 20 of any of the above schemes, and the cylindrical battery cell 20 is used to provide electrical energy to the electrical device.

[0349] The electrical device can be any of the aforementioned devices or systems that utilize cylindrical battery cells 20.

[0350] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0351] The above are merely preferred embodiments of this application and are not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A cylindrical battery cell, comprising: The outer shell has walls; An electrode assembly is disposed within the housing, the electrode assembly having a first tab; as well as A first current collector is located inside the housing, and the first electrode tab is electrically connected to the wall through the first current collector; The wall portion includes a main body area and a first connecting area that are interconnected. The first current collector includes a body area and a second connecting area. The body area is connected to the first electrode lug. The second connecting area is welded to the wall portion to form a connecting part. A portion of the connecting part is embedded in the first connecting area, and the connecting part is connected to the main body area through the first connecting area. The hardness of the first connecting area is less than the hardness of the main body area.

2. The cylindrical battery cell according to claim 1, wherein, The first connection area includes two first sub-connection areas, which are located on both sides of the connection part in the width direction of the connection part.

3. The cylindrical battery cell according to claim 1 or 2, wherein, The second connection area is stacked on top of the first connection area, and the connection portion connects the second connection area and the first connection area; The first connection area has a first surface facing the second connection area. Within the first surface, the minimum distance between the orthographic projection of the portion of the connection part embedded in the first connection area and the outer edge of the first surface is L1, which satisfies 0.05mm≤L1≤2.5mm.

4. The cylindrical battery cell according to any one of claims 1-3, wherein, The Vickers hardness value of the first connection area is greater than or equal to 50 and less than or equal to 180.

5. The cylindrical battery cell according to any one of claims 1-4, wherein, The Vickers hardness value of the main body region is greater than or equal to 70 and less than or equal to 200.

6. The cylindrical battery cell according to any one of claims 1-5, wherein, The axial direction of the cylindrical battery cell is a first direction, and the outer casing includes: The housing includes an integrally formed sidewall and a bottom wall, the sidewall surrounding the bottom wall, one end of the sidewall being connected to the bottom wall along the first direction, and the other end forming an opening, the sidewall and the bottom wall together defining a receiving cavity, the electrode assembly being received within the receiving cavity; End cap, to close the opening; The wall portion refers to either the side wall or the bottom wall.

7. The cylindrical battery cell according to claim 6, wherein, The wall portion is the sidewall; The sidewall has a first protrusion on the side facing the cavity. Along the first direction, the end cap is located on the side of the first protrusion facing the opening. At least a portion of the electrode assembly is located on the side of the first protrusion away from the opening. The body region is located at the end of the electrode assembly facing the end cap. The second connection region is welded to the first protrusion to form the connection portion. A portion of the first protrusion forms the first connection region, and another portion of the first protrusion forms a part of the body region.

8. The cylindrical battery cell according to claim 7, wherein, The first protrusion is a ring structure extending circumferentially along the sidewall.

9. The cylindrical battery cell according to claim 8, wherein, The first protrusion has a plurality of first connection areas, which are arranged at circumferential intervals along the sidewall, and each first connection area is connected to a corresponding connection part.

10. The cylindrical battery cell according to any one of claims 7-9, wherein, The sidewall is opposite to the receiving cavity and has a first groove formed at the position corresponding to the first protrusion.

11. The cylindrical battery cell according to claim 10, wherein, The wall thickness of the first protrusion is less than the wall thickness of the other parts of the first protrusion.

12. The cylindrical battery cell according to claim 10 or 11, wherein, The thickness of the first connection area is less than the wall thickness of the area of ​​the sidewall where the first protrusion is not formed.

13. The cylindrical battery cell according to any one of claims 7-12, wherein, Along the first direction, the second connection area is located on the side of the first protrusion facing the end cap, and the second connection area is welded to the side of the first protrusion facing the end cap to form the connection portion.

14. The cylindrical battery cell according to any one of claims 7-12, wherein, Along the first direction, the second connection area is located on the side of the first protrusion away from the end cap, and the second connection area is welded to the side of the first protrusion away from the end cap to form the connection portion.

15. The cylindrical battery cell according to any one of claims 7-14, wherein, The second connection area is located on the side of the body area facing the end cap in the first direction; The first current collection component further includes a transition region, which connects the body region and the second connection region. The transition region is configured to deform when the body region and the second connection region move closer to or further away from each other along the first direction.

16. The cylindrical battery cell according to claim 15, wherein, The transition zone is bent to form multiple bent segments, which are connected sequentially. The bent segments at both ends of the multiple bent segments are respectively connected to the body area and the second connection area.

17. The cylindrical battery cell according to claim 15 or 16, wherein, The end cap is provided with a pressure relief component, which is configured to release the internal pressure of the cylindrical battery cell.

18. The cylindrical battery cell according to claim 17, wherein, In a projection plane perpendicular to the first direction, the orthographic projection of the body area and the orthographic projection of the second connection area form an exhaust gap in the radial direction of the cylindrical battery cell.

19. The cylindrical battery cell according to claim 18, wherein, The pressure relief component is provided with a pressure relief groove, and at least a portion of the projection of the pressure relief groove in the first direction is located within the exhaust gap.

20. The cylindrical battery cell according to any one of claims 17-19, wherein, In a projection plane perpendicular to the first direction, the orthographic projection of the second connection area extends circumferentially along the cylindrical battery cell and is located on the periphery of the orthographic projection of the body area. The orthographic projections of the second connection area and the body area are arranged radially at intervals in the cylindrical battery cell. The diameter of the orthographic projection of the outer edge of the second connection area is D1. The orthographic projection of the transition area extends radially along the cylindrical battery cell and has a length of L2, satisfying that 1 / 15 ≤ L2 / D1 ≤ 1 / 3.

21. The cylindrical battery cell according to claim 20, wherein, 1 / 7≤L2 / D1≤1 / 4.

22. The cylindrical battery cell according to claim 20 or 21, wherein, 3mm≤L2≤15mm.

23. The cylindrical battery cell according to any one of claims 20-22, wherein, The thickness of the transition zone is T1. In a projection plane perpendicular to the first direction, the width of the orthographic projection of the transition zone in a direction perpendicular to its extension direction is W, satisfying 0.3mm. 2 ≤W×T1≤8mm 2 .

24. The cylindrical battery cell according to claim 23, wherein, 2mm≤W≤10mm.

25. The cylindrical battery cell according to claim 24, wherein, 3mm≤W≤5mm.

26. The cylindrical battery cell according to any one of claims 23-25, wherein, 0.15mm≤T1≤0.8mm.

27. The cylindrical battery cell according to claim 26, wherein, 0.3mm≤T1≤0.5mm.

28. The cylindrical battery cell according to any one of claims 15-27, wherein, The thickness of the transition region is less than the thickness of the body region; and / or The thickness of the transition region is less than the thickness of the second connection region.

29. The cylindrical battery cell according to any one of claims 7-28, wherein, The sidewall is bent at the end away from the bottom wall in the first direction to form a flange, and the flange encloses the opening. Along the first direction, a portion of the end cap is located between the flange and the first protrusion, and the flange and the first protrusion are configured to cooperate in clamping the end cap.

30. The cylindrical battery cell according to claim 29, wherein, The cylindrical battery cell also includes: A seal, at least partially disposed radially between the sidewall and the end cap of the cylindrical battery cell, is configured to seal the end cap and the sidewall.

31. The cylindrical battery cell according to claim 6, wherein, The wall portion is the sidewall; Wherein, the body region is located at one end of the electrode assembly in the first direction, and the body region is connected to the first electrode tab, the second connection region extends circumferentially along the sidewall and surrounds the body region, the second connection region is welded to the sidewall to form the connection part, a portion of the sidewall forms the first connection region, and another portion of the sidewall forms the main body region.

32. The cylindrical battery cell according to claim 31, wherein, Along the first direction, one end of the second connection area is connected to the body area, and the second connection area extends from the body area toward the end cap.

33. The cylindrical battery cell according to any one of claims 1-5, wherein, The axial direction of the cylindrical battery cell is a first direction, and the outer casing includes: The housing includes an integrally formed sidewall and a bottom wall, the sidewall surrounding the bottom wall, one end of the sidewall being connected to the bottom wall along the first direction, and the other end forming an opening, the sidewall and the bottom wall together defining a receiving cavity, the electrode assembly being received within the receiving cavity; End cap, to close the opening; The wall portion is the end cap.

34. The cylindrical battery cell according to claim 33, wherein, Along the first direction, a second protrusion is formed on the side of the end cap facing the electrode assembly. The second connection area is welded to the second protrusion to form the connection portion. A portion of the second protrusion forms the first connection area, and another portion of the second protrusion forms a part of the main body area.

35. The cylindrical battery cell according to claim 34, wherein, The second protrusion is a ring structure extending circumferentially along the sidewall.

36. The cylindrical battery cell according to claim 34 or 35, wherein, Along the first direction, the end cap has a second groove formed on the side opposite to the electrode assembly and corresponding to the position of the second protrusion.

37. The cylindrical battery cell according to any one of claims 6-36, wherein, The electrode assembly further includes a main body portion, and along the first direction, the first electrode tab is connected to one end of the main body portion, and the body region is located on the side of the first electrode tab away from the main body portion and is connected to the first electrode tab.

38. The cylindrical battery cell according to any one of claims 1-37, wherein, The material of the first current collector includes copper.

39. The cylindrical battery cell according to any one of claims 1-38, wherein, The first electrode tab is welded to the body region.

40. The cylindrical battery cell according to any one of claims 1-39, wherein, The wall thickness of the wall portion is T2, which satisfies 0.2mm≤T2≤0.8mm.

41. A battery device comprising a cylindrical battery cell as claimed in any one of claims 1-40.

42. An electrical device comprising a cylindrical battery cell as claimed in any one of claims 1-40, the cylindrical battery cell being used to provide electrical energy.

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