Cylindrical battery cell, battery device and electric device

Abstract

The present application belongs to the technical field of batteries. Provided are a cylindrical battery cell, a battery device and an electric device. The cylindrical battery cell comprises a casing, an electrode assembly and a first current collecting member. A pressure relief component is provided on a first wall of the casing, the pressure relief component is provided with a pressure relief groove, a side wall of the casing surrounds the periphery of the first wall, a protrusion is provided on an inner peripheral surface of the side wall in a protruding manner, and the protrusion and the pressure relief groove both extend in the circumferential direction of the side wall. The electrode assembly is located on the side of the protrusion facing away from the first wall. The first current collecting member comprises a body portion connected to the electrode assembly and a butt-joint portion connected to the protrusion, wherein the body portion comprises a plurality of support areas and a main body area connected to the butt-joint portion, the plurality of support areas are arranged spaced apart from each other in the circumferential direction of the main body area and are connected to an outer circumferential surface of the main body area, and the support areas are located between the electrode assembly and the protrusion in the direction of thickness of the first wall. An inner diameter of the protrusion is D1, an outer diameter of the main body area is D2, an inner diameter of the pressure relief groove is D3, D1≥D2, and D3≥0.75D2, so as to improve the pressure relief rate of the cylindrical battery cell.

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, to ensure the safety of cylindrical battery cells, a pressure relief structure is typically installed on the outer casing of the cell to release internal pressure. This allows the pressure relief structure to release the internal pressure in the event of thermal runaway. However, existing cylindrical battery cells have a low pressure relief rate during thermal runaway, which poses a risk of fire and explosion due to untimely pressure relief, resulting in low reliability of cylindrical battery cells.

[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 reliability of cylindrical battery cells.

[0006] In a first aspect, embodiments of this application provide a cylindrical battery cell, including a housing, an electrode assembly, and a first current collector; the housing includes a first wall and a side wall, the thickness direction of the first wall is the axial direction of the cylindrical battery cell, a pressure relief component is provided on the first wall, the pressure relief component is provided with a pressure relief groove, the side wall surrounds the first wall, a protrusion is provided on the inner circumferential surface of the side wall, the protrusion and the pressure relief groove both extend circumferentially along the side wall; the electrode assembly is accommodated within the housing and located on the side of the protrusion facing away from the first wall; the first current collector includes a body portion and a docking portion, the body portion being located on the side of the electrode assembly facing the housing. The first wall is located on one side and connected to the electrode assembly. The body portion includes a main body area and a plurality of support areas connected to the outer peripheral surface of the main body area. The plurality of support areas are spaced apart circumferentially along the main body area. At least a portion of the support area is located between the electrode assembly and the protrusion in the thickness direction of the first wall. The docking portion is connected to the main body area and the docking portion is connected to the protrusion to electrically connect the electrode assembly and the side wall. In the radial direction of the cylindrical battery cell, the inner diameter of the protrusion is D1, the outer diameter of the main body area is D2, and the inner diameter of the pressure relief groove is D3, satisfying that D1≥D2 and D3≥0.75D2.

[0007] In the above technical solution, the first current collector is provided with a body and a docking part. The body is located on the side of the electrode assembly facing the first wall in the thickness direction of the first wall and is connected to the electrode assembly. The docking part connects the body and the protrusion to realize the electrical connection between the electrode assembly and the side wall through the first current collector. The body includes a main body area and multiple support areas connected to the outer peripheral surface of the main body area. The multiple support areas are spaced apart circumferentially along the main body area, and at least a portion of the support areas is located between the electrode assembly and the protrusion in the thickness direction of the first wall. This allows the body of the first current collector to support the electrode assembly between the protrusion and the electrode assembly while also enabling the thermal runaway gas inside the cylindrical battery cell to be vented through the gaps between the multiple support areas. This improves the internal venting smoothness of the cylindrical battery cell and increases the depressurization rate of the cylindrical battery cell. The inner diameter of the protrusion is set to be greater than or equal to that of the body. The outer diameter of the main body area is set, and the inner diameter of the pressure relief groove is set to be greater than or equal to 0.75 times the outer diameter of the main body area. This makes the main body area of ​​the main body structure with its projection in the thickness direction of the first wall located inside the protrusion, and the pressure relief groove structure with its projection in the thickness direction of the first wall located close to the outer edge of the main body area or located outside the main body area. This reduces the obstruction of the protrusion and the main body area on the exhaust path inside the cylindrical battery cell, so that the thermal runaway gas inside the cylindrical battery cell can enter the side of the main body facing the first wall through the gap between multiple support areas and be directly released through the area with the pressure relief groove on the pressure relief component on the first wall. This can effectively improve the smoothness of internal exhaust and the pressure relief rate of the cylindrical battery cell, which helps to reduce the risk of the cylindrical battery cell bursting or exploding due to untimely pressure relief, thereby improving the stability and reliability of the cylindrical battery cell.

[0008] In some embodiments, D1 ≥ D3.

[0009] In the above technical solution, by setting the inner diameter of the protrusion to be greater than or equal to the inner diameter of the pressure relief groove, the pressure relief groove is set in the thickness direction of the first wall corresponding to the gap between the protrusion and the main body area of ​​the body. This can further reduce the obstruction and blockage of the area of ​​the first wall used for pressure relief by the protrusion and the main body area, thereby further improving the internal venting smoothness and pressure relief rate of the cylindrical battery cell. This is beneficial to further reduce the risk of the cylindrical battery cell bursting or exploding due to untimely pressure relief, and further improve the stability and reliability of the cylindrical battery cell in use.

[0010] In some embodiments, the outer diameter of the body portion along the radial direction of the cylindrical battery cell is D4, satisfying that D1≤0.95D4.

[0011] In the above technical solution, by setting the inner diameter of the protrusion to be less than 0.95 times the outer diameter of the body, the projection of the inner circumferential surface of the protrusion in the thickness direction of the first wall is a structure located inside the body. This allows the multiple support areas connected to the outer circumferential surface of the main body to extend better between the electrode assembly and the protrusion, thereby improving the overlap effect between the multiple support areas and the protrusion. This further enhances the support effect of the body of the first current collector on the electrode assembly, and also improves the effect of the body of the first current collector against the expansion of the electrode assembly during the use of the cylindrical battery cell, thereby improving the stability of the cylindrical battery cell.

[0012] In some embodiments, the maximum proportion of the plurality of support regions in the circumferential direction of the main body region is P, satisfying 40% ≤ P ≤ 90%.

[0013] In the above technical solution, on the one hand, by setting the maximum proportion of multiple support areas in the circumferential direction of the main body area to be greater than or equal to 40%, the maximum space occupied by the multiple support areas on their respective circumferences is greater than or equal to 40%, thereby improving the effect of the main body overlapping with the protrusions through the multiple support areas, thus improving the support effect of the main body of the first current collector on the electrode assembly. In addition, during the use of the cylindrical battery cell, it can also improve the effect of the main body of the first current collector against the expansion of the electrode assembly. On the other hand, by setting the maximum proportion of multiple support areas in the circumferential direction of the main body area to be less than or equal to 90%, the maximum space occupied by the multiple support areas on their respective circumferences is less than or equal to 90%, thereby alleviating the phenomenon that the multiple support areas are too close together in the circumferential direction of the main body area, thereby increasing the size of the gap between the multiple support areas. This allows the thermal runaway gas inside the cylindrical battery cell to enter the side of the main body facing the first wall more smoothly through the gap between the multiple support areas, thereby improving the internal exhaust smoothness and depressurization rate of the cylindrical battery cell, which is beneficial to reducing the risk of the cylindrical battery cell bursting or exploding due to untimely depressurization.

[0014] In some embodiments, 50% ≤ P ≤ 80%.

[0015] In the above technical solution, on the one hand, by further setting the maximum proportion of multiple support areas in the circumferential direction of the main body area to be greater than or equal to 50%, the maximum space occupied by multiple support areas on their respective circumferences is greater than or equal to 50%, thereby further improving the effect of the main body of the main body overlapping with the protrusions through multiple support areas, thus further improving the support effect of the main body of the first current collector on the electrode assembly. In addition, during the use of the cylindrical battery cell, it can also further improve the effect of the main body of the first current collector against the expansion of the electrode assembly. On the other hand, by further setting the maximum proportion of multiple support areas in the circumferential direction of the main body area to be less than or equal to 80%, the maximum space occupied by multiple support areas on their respective circumferences is less than or equal to 80%, thereby further alleviating the phenomenon that the multiple support areas are too close together in the circumferential direction of the main body area, thereby further increasing the size of the gap between multiple support areas. This allows the thermal runaway gas inside the cylindrical battery cell to enter the side of the main body facing the first wall more smoothly through the gap between multiple support areas, thereby further improving the internal exhaust smoothness and depressurization rate of the cylindrical battery cell, which is conducive to further reducing the risk of the cylindrical battery cell bursting or exploding due to untimely depressurization.

[0016] In some embodiments, the protrusion protrudes radially from the inner circumferential surface of the sidewall of the cylindrical battery cell by a dimension L1. In a projection plane perpendicular to the thickness direction of the first wall, the portion of the orthographic projection of the support area overlapping the orthographic projection of the protrusion in the radial direction of the cylindrical battery cell has a dimension L2, satisfying 0.2L1≤L2≤0.9L1.

[0017] In the above technical solution, by setting the radial dimension of the portion of the support area projected in the thickness direction of the first wall and overlapping with the protrusion in the cylindrical battery cell to 0.2 to 0.9 times the dimension of the protrusion protruding from the inner circumferential surface of the sidewall, the length of the support area extending radially from the cylindrical battery cell to the protrusion and the electrode assembly is 0.2 to 0.9 times the dimension of the protrusion protruding from the inner circumferential surface of the sidewall. On the one hand, setting the length of the support area extending radially from the cylindrical battery cell to the protrusion and the electrode assembly to be greater than or equal to 0.2 times the dimension of the protrusion protruding from the inner circumferential surface of the sidewall can further improve the overlapping effect between the support area and the protrusion, thereby further improving the support effect of the body of the first current collector on the electrode assembly. Furthermore, in the cylindrical battery cell... During the use of the cell, the body of the first current collector can be further improved to resist the expansion of the electrode assembly. On the other hand, setting the length of the support area extending radially from the cylindrical cell to between the protrusion and the electrode assembly to be less than or equal to 0.9 times the size of the inner circumferential surface of the protrusion protruding from the sidewall can alleviate the phenomenon of excessive overlap between the support area and the protrusion, thereby reducing the difficulty of assembling the first current collector into the casing. Moreover, when the cylindrical cell is depressurized, the body of the first current collector can easily detach from the protrusion and the electrode assembly under the impact of thermal runaway gas, which is conducive to improving the internal venting smoothness and depressurization rate of the cylindrical cell, thereby further reducing the risk of the cylindrical cell bursting or exploding due to untimely depressurization.

[0018] In some embodiments, 2mm ≤ L1 ≤ 5mm.

[0019] In the above technical solution, by setting the size of the protrusion protruding from the inner circumferential surface of the sidewall to 2mm to 5mm, the radial dimension of the protrusion in the cylindrical battery cell is 2mm to 5mm. On the one hand, setting the size of the protrusion protruding from the inner circumferential surface of the sidewall to be greater than or equal to 2mm can reduce the difficulty of the connection between the protrusion and the support area, thereby reducing the difficulty of the body of the first current collector being placed between the protrusion and the electrode assembly, and improving the support effect of the protrusion on the electrode assembly. On the other hand, setting the size of the protrusion protruding from the inner circumferential surface of the sidewall to be less than or equal to 5mm can reduce the space occupied by the protrusion in the radial direction of the cylindrical battery cell, which is conducive to reducing the obstruction of the exhaust path inside the cylindrical battery cell by the protrusion. This can effectively improve the internal exhaust smoothness and pressure relief rate of the cylindrical battery cell, which is conducive to reducing the risk of the cylindrical battery cell bursting or exploding due to untimely pressure relief, thereby improving the stability and reliability of the cylindrical battery cell in use.

[0020] In some embodiments, L2 ≥ 1 mm.

[0021] In the above technical solution, by setting the size of the portion of the projection of the support area in the thickness direction of the first wall that overlaps with the protrusion in the radial direction of the cylindrical battery cell to be greater than or equal to 1 mm, the length of the support area extending in the radial direction of the cylindrical battery cell to the distance between the protrusion and the electrode assembly is greater than or equal to 1 mm. This can improve the overlapping effect between the support area and the protrusion, thereby improving the support effect of the body of the first current collector on the electrode assembly. Furthermore, during the use of the cylindrical battery cell, it can further improve the effect of the body of the first current collector against the expansion of the electrode assembly.

[0022] In some embodiments, the thickness of the body portion is T1, satisfying 0.1mm≤T1≤0.6mm.

[0023] In the above technical solution, on the one hand, setting the thickness of the body to be greater than or equal to 0.1mm can effectively improve the structural strength of the body, thereby enhancing the support effect of the body on the electrode assembly between the protrusion and the electrode assembly. In addition, during the use of the cylindrical battery cell, it can also improve the effect of the body of the first current collector against the expansion of the electrode assembly, which is conducive to reducing the risk of deformation or detachment of the body under the expansion of the electrode assembly. On the other hand, setting the thickness of the body to be less than or equal to 0.6mm can reduce the manufacturing difficulty and manufacturing cost of the body of the first current collector, and can effectively reduce the space occupied by the body in the thickness direction of the first wall, which is conducive to improving the internal space utilization of the cylindrical battery cell.

[0024] In some embodiments, the electrode assembly includes a main body and a first tab, wherein the first tab is connected to one end of the main body facing the first wall along the thickness direction of the first wall; wherein the main body region is welded to the first tab to form a plurality of first connecting portions, and a plurality of support regions are welded to the first tab to form a plurality of second connecting portions, wherein the sum of the lengths of the plurality of second connecting portions is greater than or equal to the sum of the lengths of the plurality of first connecting portions.

[0025] In the above technical solution, the main body area of ​​the body is welded to the first electrode tab to form multiple first connection parts, and multiple support areas of the body are welded to the first electrode tab to form multiple second connection parts. This makes both the main body area and the support areas welded to the first electrode tab, thereby increasing the current conduction area between the first electrode tab and the body, and improving the connection stability and reliability between the body of the first current collector and the first electrode tab of the electrode assembly. Since the outer ring length of the first electrode tab is greater than the inner ring length, the current flow requirement of the outer ring of the first electrode tab is greater than that of the inner ring. By setting the total length of the multiple second connection parts formed by welding the multiple support areas to the first electrode tab to be greater than the total length of the multiple first connection parts formed by welding the main body area to the first electrode tab, the current conduction area between the outer ring of the first electrode tab and the body is greater than the current conduction area between the inner ring of the first electrode tab and the body, thereby improving the current flow balance between the inner and outer rings of the first electrode tab. This helps to reduce the phenomenon of local lithium plating or increased internal resistance in the electrode assembly during use.

[0026] In some embodiments, a plurality of the first connecting portions are arranged circumferentially spaced along the sidewall, and the first connecting portions extend radially along the cylindrical battery cell.

[0027] In the above technical solution, by setting the multiple first connecting parts formed by welding the main body region and the first tab to a structure arranged circumferentially along the sidewall, and each first connecting part being a structure extending radially along the cylindrical battery cell, on the one hand, the welding difficulty between the main body region and the first tab can be reduced, and the layout between the multiple first connecting parts can be optimized, which is conducive to alleviating the interference between the multiple first connecting parts. On the other hand, it can realize that the first tab is connected to the main body region at multiple positions in the circumferential direction of the sidewall, and that the first tab is connected to the main body region at multiple positions in the radial direction of the cylindrical battery cell, so that the multi-ring structure of the first tab can be connected to the main body region. This not only increases the current conduction area between the first tab and the main body region, but also improves the overcurrent balance between the electrode assembly and the main body region, thereby reducing the risk of local lithium plating in the electrode assembly during use.

[0028] In some embodiments, a plurality of the second connecting portions are arranged circumferentially spaced along the sidewall, and the second connecting portions extend radially along the cylindrical battery cell.

[0029] In the above technical solution, by setting multiple second connecting parts formed by welding multiple support areas to the first tab as a structure arranged circumferentially along the sidewall, and each second connecting part is a structure extending radially along the cylindrical battery cell, on the one hand, the welding difficulty between multiple support areas and the first tab can be reduced, and the layout between multiple second connecting parts can be optimized, which is conducive to alleviating the interference between multiple second connecting parts. On the other hand, it can realize that multiple positions of the first tab in the circumferential direction of the sidewall are connected to the support area, and multiple positions of the first tab in the radial direction of the cylindrical battery cell can be connected to the support area, so that the multi-ring structure of the first tab can be connected to the support area. This not only increases the current conduction area between the first tab and the support area, but also improves the overcurrent balance between the electrode assembly and the support area, thereby reducing the risk of local lithium plating in the electrode assembly during use.

[0030] In some embodiments, each of the support regions is welded to the first electrode tab to form a second connection portion.

[0031] In the above technical solution, by welding each support area of ​​the main body to the first electrode tab, multiple support areas arranged at intervals in the circumferential direction of the main body are welded to the first electrode tab and correspondingly form a second connection part. On the one hand, this can further improve the connection stability and reliability between the first electrode tab and the main body. On the other hand, it can realize that the first electrode tab is connected to multiple support areas in the circumferential direction of the sidewall, which is conducive to improving the current balance between the electrode assembly and the first current collector, so as to reduce the risk of local lithium plating in the electrode assembly during use.

[0032] In some embodiments, the first current collection member includes a plurality of docking portions, the plurality of docking portions being arranged at circumferential intervals along the main body region and all connected to the main body region, and the plurality of docking portions being connected to the protrusion.

[0033] In the above technical solution, the first current collector is provided with multiple docking parts, and the multiple docking parts are arranged at intervals along the circumference of the main body area and are all connected to the protrusion. This allows the protrusion to be connected to docking parts at multiple positions in the circumferential direction of the sidewall. On the one hand, this can further improve the connection stability and reliability between the first current collector and the protrusion. On the other hand, it can further increase the flow guiding area between the first current collector and the protrusion, and further improve the flow balance between the first current collector and the protrusion, so as to reduce the risk of local temperature rise of the protrusion.

[0034] In some embodiments, multiple mating portions are welded to the protrusion and correspondingly form multiple third connecting portions, each of which corresponds to a mating portion. The third connecting portions extend circumferentially along the sidewall. In a projection plane perpendicular to the thickness direction of the first wall, the outer edges of the orthographic projections of the multiple third connecting portions are all located on a first circle, and the sum of the arc lengths of the outer edges of the orthographic projections of the multiple third connecting portions is L3, and the circumference of the first circle is L4, satisfying that L3 ≥ 0.5L4.

[0035] In the above technical solution, by setting the sum of the arc lengths of the outer edges of the orthographic projections of the multiple third connecting parts in the thickness direction of the first wall to be greater than or equal to 0.5 times the circumference of the first circle, the proportion of the multiple third connecting parts on the first circle is greater than or equal to 50%, thereby increasing the flow guiding area between the first current collector and the protrusion, so as to improve the flow guiding effect between the first current collector and the shell, and thus reduce the phenomenon of increased internal resistance of the cylindrical battery cell during use.

[0036] In some embodiments, L3 ≥ 0.8L4.

[0037] In the above technical solution, by further setting the sum of the arc lengths of the outer edges of the orthographic projections of the multiple third connecting parts in the thickness direction of the first wall to be greater than or equal to 0.8 times the circumference of the first circle, the proportion of the multiple third connecting parts on the first circle is greater than or equal to 80%, thereby further increasing the flow guiding area between the first current collector and the protrusion, so as to further improve the flow guiding effect between the first current collector and the shell, which is conducive to further reducing the phenomenon of increased internal resistance of the cylindrical battery cell during use.

[0038] In some embodiments, the mating portion has a connection area that is welded to the protrusion, the connection area being an arc-shaped structure extending circumferentially along the sidewall.

[0039] In the above technical solution, the docking part is provided with a connection area for welding to the protrusion. By setting the connection area as an arc-shaped structure extending circumferentially along the side wall, the connection area and the protrusion can fit together. On the one hand, it is convenient to realize the welding connection between the connection area of ​​the docking part and the protrusion to form a third connection part extending circumferentially along the side wall, which helps to reduce the welding difficulty between the docking part and the protrusion. On the other hand, it can realize that the connection area can be welded to the protrusion at multiple positions in the circumferential direction of the side wall. This reduces the need to rotate and adjust the position of the first current collector after it is assembled into the housing, further reducing the welding difficulty between the first current collector and the protrusion, thereby effectively improving the assembly efficiency of the cylindrical battery cell.

[0040] In some embodiments, a plurality of the docking portions are connected to the outer peripheral surface of the main body region, and the docking portions and the support region are alternately arranged along the circumferential direction of the main body region.

[0041] In the above technical solution, by setting multiple docking parts arranged at intervals along the circumference of the main body area to a structure that are all connected to the outer circumferential surface of the main body area, it is beneficial to reduce the connection difficulty between the main body area and the docking parts, thereby reducing the molding difficulty of the first current collector component. In particular, by setting the docking parts and the support area to a structure that is alternately arranged in the circumference of the main body area, on the one hand, the interference between the docking parts and the support area can be reduced, thereby reducing the connection difficulty between the docking parts and the protrusion, and reducing the assembly difficulty between the body part and the electrode assembly. On the other hand, it can improve the regularity of the first current collector component and optimize the structural layout of the docking parts and the support area, thereby reducing the difficulty of assembling the first current collector component into the shell.

[0042] In some embodiments, the electrode assembly is provided with a central through hole, which extends through both ends of the electrode assembly along the thickness direction of the first wall, and the main body region is provided with an exhaust hole, which extends through both sides of the main body region along the thickness direction of the first wall and is connected to the central through hole; wherein, along the thickness direction of the first wall, the projection of the hole wall surface of the central through hole is located within the exhaust hole.

[0043] In the above technical solution, by providing an exhaust hole that penetrates the main body area along the thickness direction of the first wall on the main body of the first current collector, the exhaust hole is connected to the central through hole of the electrode assembly, and the projection of the hole wall surface of the central through hole in the thickness direction of the first wall is set to be located inside the exhaust hole, so that the diameter of the exhaust hole is greater than or equal to the diameter of the central through hole, the thermal runaway gas in the central through hole can easily enter the side of the main body facing the first wall through the exhaust hole when the cylindrical battery cell experiences thermal runaway, and then be directly released through the area with the pressure relief groove on the pressure relief component on the first wall. This helps to improve the internal exhaust smoothness of the cylindrical battery cell, thereby effectively reducing the risk of the cylindrical battery cell bursting or exploding due to untimely pressure relief, and improving the stability and reliability of the cylindrical battery cell in use.

[0044] In some embodiments, the diameter of the central through hole is D5, and the diameter of the vent hole is D6, satisfying that D6≥1.5D5.

[0045] In the above technical solution, by further setting the diameter of the vent hole to be greater than or equal to 1.5 times the diameter of the central through hole, the thermal runaway gas in the central through hole can be further improved to enter the side of the main body facing the first wall through the vent hole when thermal runaway occurs in the cylindrical battery cell. This is conducive to further improving the internal venting smoothness of the cylindrical battery cell, thereby further reducing the risk of the cylindrical battery cell bursting or exploding due to untimely pressure relief, and further improving the stability and reliability of the cylindrical battery cell in use.

[0046] In some embodiments, the length of the support region along the radial direction of the cylindrical battery cell is L5, satisfying 0.5D2≥L5.

[0047] In the above technical solution, by setting the radius of the main body area of ​​the main body to be greater than or equal to the length of the support area of ​​the main body protruding from the outer circumference of the main body area in the radial direction of the cylindrical battery cell, the phenomenon of insufficient structural strength of the main body caused by excessive space occupied by the support area in the main body can be alleviated. This can further improve the phenomenon of poor support effect of the main body on the electrode assembly in the thickness direction of the first wall, and further improve the effect of the main body against the expansion of the electrode assembly during the use of the cylindrical battery cell.

[0048] In some embodiments, the housing has an internal cavity, the body is configured to divide the cavity into a first cavity and a second cavity that are in communication with each other, the electrode assembly is housed in the first cavity, the second cavity is located between the body and the first wall in the thickness direction of the first wall, and the pressure relief component is configured to split at least a portion of the pressure relief groove when the cylindrical battery cell is depressurized, so as to release the internal pressure of the second cavity; wherein, along the thickness direction of the first wall, the maximum size of the second cavity is H1, the maximum size of the housing is H2, and 0.003≤H1 / H2≤0.06 is satisfied.

[0049] In the above technical solution, the main body divides the internal cavity of the outer casing into a first cavity and a second cavity arranged along the thickness direction of the first wall. The electrode assembly is disposed in the first cavity, and the second cavity is located between the first wall and the main body. By configuring the pressure relief component to be able to crack along at least a portion of the pressure relief groove and release the internal pressure of the second cavity when the cylindrical battery cell is depressurized, the area of ​​the pressure relief component with the pressure relief groove on the first wall corresponds to the structure of the second cavity. The cylindrical battery cell with this structure can achieve separation between the electrode assembly and the pressure relief component through the second cavity, thereby alleviating the obstruction and shielding of the pressure relief component by the electrode assembly when the cylindrical battery cell is depressurized. This allows the interior of the outer casing to have a second cavity for buffering and releasing thermal runaway gases, which is beneficial to improving the internal venting smoothness of the cylindrical battery cell. The maximum dimension of the second cavity in the thickness direction of the first wall is the outer casing's... The maximum dimension of the first wall in the thickness direction is 0.003 to 0.06 times. On the one hand, by setting the maximum dimension of the second cavity in the thickness direction of the first wall to be greater than or equal to 0.003 times the maximum dimension of the outer shell in the thickness direction of the first wall, sufficient space is provided between the main body and the first wall to buffer and discharge thermal runaway gas. This is beneficial to improve the internal venting smoothness and depressurization rate of the cylindrical battery cell, thereby reducing the risk of the cylindrical battery cell bursting or exploding due to untimely depressurization. On the other hand, by setting the maximum dimension of the second cavity in the thickness direction of the first wall to be less than or equal to 0.06 times the maximum dimension of the outer shell in the thickness direction of the first wall, the phenomenon of the second cavity occupying too much space in the cavity for setting electrode components can be alleviated, thereby improving the internal space utilization of the cylindrical battery cell and increasing the energy density of the cylindrical battery cell.

[0050] In some embodiments, 0.01 ≤ H1 / H2 ≤ 0.03.

[0051] In the above technical solution, on the one hand, the maximum dimension of the second cavity in the thickness direction of the first wall is further set to be greater than or equal to 0.01 times the maximum dimension of the outer shell in the thickness direction of the first wall, so that there is more space between the main body and the first wall to buffer and discharge thermal runaway gas. This is beneficial to further improve the internal exhaust smoothness and depressurization rate of the cylindrical battery cell, thereby further reducing the risk of the cylindrical battery cell bursting or exploding due to untimely depressurization. On the other hand, the maximum dimension of the second cavity in the thickness direction of the first wall is further set to be less than or equal to 0.03 times the maximum dimension of the outer shell in the thickness direction of the first wall, so as to further alleviate the phenomenon that the second cavity occupies too much space in the cavity for setting electrode components, thereby further improving the internal space utilization rate of the cylindrical battery cell and further improving the energy density of the cylindrical battery cell.

[0052] In some embodiments, 0.4mm ≤ H1 ≤ 4mm.

[0053] In the above technical solution, by setting the maximum size of the second cavity in the thickness direction of the first wall to 0.4mm to 4mm, on the one hand, more space can be provided between the main body and the first wall to buffer and discharge thermal runaway gas. This reduces the obstruction of the exhaust path inside the cylindrical battery cell by the electrode assembly and the main body when the cylindrical battery cell is depressurized, thereby further improving the smoothness of internal exhaust and the depressurization rate of the cylindrical battery cell. This reduces the risk of the cylindrical battery cell bursting or exploding due to untimely depressurization. On the other hand, it alleviates the phenomenon that the second cavity occupies too much space in the accommodating cavity for setting the electrode assembly, thereby further improving the internal space utilization of the cylindrical battery cell and further improving the energy density of the cylindrical battery cell.

[0054] In some embodiments, the capacity of the cylindrical battery cell is C, which satisfies 0.005mm / Ah ≤ H1 / C ≤ 0.2mm / Ah.

[0055] In the above technical solution, on the one hand, by setting the ratio of the maximum dimension of the second cavity in the thickness direction of the first wall to the capacitance of the cylindrical battery cell to be greater than or equal to 0.005 mm / Ah, the second cavity has sufficient space to buffer and discharge thermal runaway gas when the cylindrical battery cell is depressurized. This helps to match the space inside the casing used for venting with the gas generation rate of the cylindrical battery cell during thermal runaway, thereby improving the smoothness of internal venting of the cylindrical battery cell and effectively reducing the risk of the cylindrical battery cell bursting or exploding due to untimely depressurization. On the other hand, by setting the ratio of the maximum dimension of the second cavity in the thickness direction of the first wall to the capacitance of the cylindrical battery cell to be less than or equal to 0.2 mm / Ah, the phenomenon of excessive waste of space inside the casing used for venting is alleviated, thereby improving the internal space utilization rate of the cylindrical battery cell and increasing the energy density of the cylindrical battery cell.

[0056] In some embodiments, the positive electrode material of the cylindrical battery cell includes lithium transition metal oxide, and H1 and C further satisfy 0.01mm / Ah≤H1 / C≤0.2mm / Ah; or, the positive electrode material of the cylindrical battery cell includes lithium phosphate, and H1 and C further satisfy 0.005mm / Ah≤H1 / C≤0.1mm / Ah.

[0057] In the above technical solution, when the positive electrode material of the cylindrical battery cell includes lithium transition metal oxide, by further adjusting the ratio of the maximum dimension of the second cavity in the thickness direction of the first wall to the capacitance of the cylindrical battery cell from 0.01 mm / Ah to 0.2 mm / Ah, the space inside the casing used for venting can be further matched with the gas generation rate of the cylindrical battery cell during thermal runaway. On the one hand, this can further improve the internal venting smoothness of the cylindrical battery cell, thereby further reducing the risk of the cylindrical battery cell bursting or exploding due to untimely pressure relief. On the other hand, it can further alleviate the phenomenon of excessive waste of space inside the casing used for venting, thereby further improving the internal space utilization rate of the cylindrical battery cell and helping to further improve the energy density of the cylindrical battery cell. Similarly, when the positive electrode material of the cylindrical battery cell includes lithium phosphate, by further adjusting the ratio of the maximum dimension of the second cavity in the thickness direction of the first wall to the capacitance of the cylindrical battery cell from 0.005 mm / Ah to 0.1 mm / Ah, the space inside the casing used for venting can be further matched with the gas generation rate of the cylindrical battery cell during thermal runaway. On the one hand, this can further improve the internal venting smoothness of the cylindrical battery cell, thereby further reducing the risk of the cylindrical battery cell bursting or exploding due to untimely pressure relief. On the other hand, it can further alleviate the phenomenon of excessive waste of space inside the casing used for venting, thereby further improving the internal space utilization rate of the cylindrical battery cell and helping to further improve the energy density of the cylindrical battery cell.

[0058] In some embodiments, the outer diameter of the electrode assembly is D7 along the radial direction of the cylindrical battery cell, satisfying 0.7≤D1 / D7≤0.95.

[0059] In the above technical solution, by setting the ratio of the inner diameter of the protrusion to the outer diameter of the electrode assembly to 0.7 to 0.95, on the one hand, setting the inner diameter of the protrusion to be greater than or equal to 0.7 times the outer diameter of the electrode assembly, so that most of the area of ​​the electrode assembly is a structure set on the inner side of the protrusion in the thickness direction of the first wall, thereby reducing the obstruction of the protrusion on the exhaust path inside the cylindrical battery cell, which is beneficial to improving the smoothness of internal exhaust and pressure relief rate of the cylindrical battery cell, and thus effectively reducing the risk of the cylindrical battery cell bursting or exploding due to untimely pressure relief. On the other hand, setting the inner diameter of the protrusion to be less than or equal to 0.95 times the outer diameter of the electrode assembly, so that the electrode assembly and the protrusion are a structure in which the projected portion overlaps in the thickness direction of the first wall, thereby improving the support effect of the protrusion on the electrode assembly through the body part, and also improving the effect of the body part of the first current collector against the expansion of the electrode assembly during the use of the cylindrical battery cell.

[0060] In some embodiments, 0.75 ≤ D1 / D7 ≤ 0.9.

[0061] In the above technical solution, on the one hand, the inner diameter of the protrusion is further set to be greater than or equal to 0.75 times the outer diameter of the electrode assembly, so as to further increase the area of ​​the region of the electrode assembly corresponding to the inner side of the protrusion in the thickness direction of the first wall. This can further reduce the obstruction of the protrusion on the exhaust path inside the cylindrical battery cell, which is conducive to further improving the internal exhaust smoothness and pressure relief rate of the cylindrical battery cell. In this way, the risk of the cylindrical battery cell bursting or exploding due to untimely pressure relief can be further reduced. On the other hand, the inner diameter of the protrusion is further set to be less than or equal to 0.9 times the outer diameter of the electrode assembly, so as to further increase the area of ​​the region where the electrode assembly and the protrusion overlap in the thickness direction of the first wall. This can further improve the support effect of the protrusion on the electrode assembly through the body part, and can also further improve the effect of the body part of the first current collector against the expansion of the electrode assembly during the use of the cylindrical battery cell.

[0062] In some embodiments, the projection of the pressure relief groove is located within the second cavity along the thickness direction of the first wall.

[0063] In the above technical solution, by setting the pressure relief groove as a structure whose projection in the thickness direction of the first wall is located in the second cavity, the area where the pressure relief component on the first wall is set with the pressure relief groove is a structure corresponding to the second cavity in the thickness direction of the first wall. This makes it easier to discharge the thermal runaway gas in the second cavity when the cylindrical battery cell experiences thermal runaway and the pressure relief component cracks along at least part of the pressure relief groove to release pressure. This is beneficial to further improve the emission rate of the thermal runaway gas in the second cavity, thereby further improving the pressure relief rate of the cylindrical battery cell and further reducing the risk of the cylindrical battery cell bursting or exploding due to untimely pressure relief.

[0064] In some embodiments, the mating portion includes a connecting region and an elastic region; the connecting region is disposed on the side of the main body region facing the first wall in the thickness direction of the first wall, and the connecting region is connected to the protrusion; the elastic region connects the connecting region and the main body region, and the elastic region is configured to be deformable.

[0065] In the above technical solution, the docking part is provided with a connection area and an elastic area. The connection area is connected to the protrusion, and the elastic area is connected between the main body area and the connection area to realize the electrical connection between the protrusion and the main body. By setting the connection area in the thickness direction of the first wall on the side of the main body area facing the first wall, and setting the elastic area in a structure that can deform when the main body area and the connection area move closer or further away from each other along the thickness direction of the first wall, the elastic area can play a certain buffering role between the main body area and the connection area. In this way, when the electrode assembly shakes or shifts, it can alleviate the rigid tension between the main body area and the connection area, between the main body area and the electrode assembly, and between the connection area and the protrusion. This is beneficial to further reduce the risk of connection failure between the main body area and the electrode assembly and between the connection area and the protrusion, and also to reduce the phenomenon of the first current collector being damaged by tension.

[0066] In some embodiments, the elastic 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 main body region and the connecting region.

[0067] In the above technical solution, by setting the elastic region as a structure of multiple bent segments connected in sequence by bending, and the bent segments at both ends of the multiple bent segments are respectively connected to the main body region and the connecting region, the deformation capacity of the elastic region when the main body region and the connecting region move closer or further away from each other along the thickness direction of the first wall can be increased, so as to further improve the buffering effect of the elastic region between the main body region and the connecting region, and further reduce the phenomenon of rigid tension between the main body region and the connecting region, between the main body region and the electrode assembly, and between the connecting region and the protrusion.

[0068] In some embodiments, in a projection plane perpendicular to the thickness direction of the first wall, the orthographic projection of the connection area extends circumferentially along the sidewall and is located on the periphery of the orthographic projection of the main body area, and the orthographic projection of the connection area and the orthographic projection of the main body area are arranged radially spaced apart in the cylindrical battery cell to form an exhaust gap between the orthographic projection of the connection area and the orthographic projection of the main body area.

[0069] In the above technical solution, in the projection plane perpendicular to the thickness direction of the first wall, by setting the orthographic projection of the connecting area and the orthographic projection of the main body area to form 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 first wall through the exhaust gap between the connecting area and the main body area and then be released. 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.

[0070] In some embodiments, at least a portion of the projection of the pressure relief groove is located within the exhaust gap along the thickness direction of the first wall.

[0071] In the above technical solution, by setting the pressure relief groove to a structure in which at least a portion of the projection of the first wall in the thickness direction is located within the exhaust gap, the pressure relief groove is a structure in which at least a portion of the first wall in the thickness direction corresponds to the exhaust gap between the connecting area and the main 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.

[0072] In some embodiments, in a projection plane perpendicular to the thickness direction of the first wall, the diameter of the orthographic projection of the outer edge of the connection area is D8, and the orthographic projection of the elastic area extends radially along the cylindrical battery cell with a length of L6, satisfying 1 / 15≤L6 / D8≤1 / 3.

[0073] In the above technical solution, in the projection plane perpendicular to the thickness direction of the first wall, the orthographic projections of the connecting area and the main body area are arranged at intervals in the radial direction of the cylindrical battery cell. Furthermore, the ratio of the length of the elastic region 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 connecting area is set to 1 / 15 to 1 / 3. This alleviates the problem of the elastic region occupying too small a size in the radial direction of the cylindrical battery cell, and helps to expand the exhaust space between the connecting area and the main body area. This allows the thermal runaway gas inside the cylindrical battery cell to pass through the exhaust space between the connecting area and the main body area and then through the pressure relief component on the first wall. The pressure relief groove is designed to release pressure, thereby improving the internal venting smoothness of the cylindrical battery cell and increasing its pressure relief rate. 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 problem of insufficient support strength between the main body area and the connecting area caused by the excessive radial size of the elastic zone in the cylindrical battery cell. This effectively improves the support effect of the first current collector on the electrode assembly and its resistance to the expansion of the electrode assembly during use, thus mitigating excessive expansion or displacement of the electrode assembly. Ultimately, this contributes to improving the stability and reliability of the cylindrical battery cell.

[0074] In some embodiments, 1 / 7 ≤ L6 / D8 ≤ 1 / 4.

[0075] In the above technical solution, in the projection plane perpendicular to the thickness direction of the first wall, by further setting the ratio of the length of the elastic region 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 connecting area to 1 / 7 to 1 / 4, the problem of the elastic region occupying too small a size in the radial direction of the cylindrical battery cell can be further alleviated. This is beneficial to further expand the exhaust space between the connecting area and the main body area, so that the thermal runaway gas inside the cylindrical battery cell can be released through the exhaust space between the connecting area and the main body area through the area with the pressure relief groove on the pressure relief component on the first wall, thereby further improving the cylindrical battery cell's thermal runaway gas efficiency. The improved internal venting of the battery cell enhances the depressurization rate of the cylindrical battery cell, thereby reducing the risk of bursting or exploding due to untimely depressurization. Furthermore, it alleviates the problem of insufficient support strength between the main body and connecting areas caused by the excessive radial size of the elastic zone within the cylindrical battery cell. This further enhances the support effect of the first current collector on the electrode assembly and its resistance to expansion during use, mitigating excessive expansion or displacement of the electrode assembly. Ultimately, this contributes to improving the stability and reliability of the cylindrical battery cell.

[0076] In some embodiments, 3mm ≤ L6 ≤ 15mm.

[0077] In the above technical solution, in the projection plane perpendicular to the thickness direction of the first wall, by setting the length of the elastic region 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 elastic region in the radial direction of the cylindrical battery cell to be greater than or equal to 3mm can increase the exhaust space between the connection area and the main body area, so that the thermal runaway gas inside the cylindrical battery cell can be released through the exhaust space between the connection area and the main body area and then through the area with the pressure relief groove on the pressure relief component on the first wall, which is beneficial to improving the internal exhaust smoothness of the cylindrical battery cell. On the other hand, setting the length of the elastic region in the radial direction of the cylindrical battery cell to be less than or equal to 15mm can alleviate the phenomenon that the elastic region is too long and therefore the support strength of the elastic region between the main body area and the 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.

[0078] In some embodiments, the thickness of the elastic region is T2, and the width of the orthographic projection of the elastic region in a projection plane perpendicular to the thickness direction of the first wall, in a direction perpendicular to its extension direction, is W, satisfying 0.3mm. 2 ≤W×T2≤8mm 2 .

[0079] In the above technical solution, the product of W and T2 is set to 0.3mm. 2 up to 8mm 2 On the one hand, the product of W and T2 is set to be less than or equal to 8mm. 2 This design can alleviate the problem of excessive deformation difficulty in the elastic zone caused by excessively large W and T2 values. It enhances the elastic zone's ability to deform when the main body and connecting areas move closer or further apart along the thickness of the first wall. This allows the elastic zone to act as a better buffer between the main body and connecting areas, reducing rigid tension between the main body and connecting areas, between the main body and the electrode assembly, and between the connecting area and the protrusion during electrode assembly wobbling or displacement. Furthermore, setting the product of W and T2 to be greater than or equal to 0.3 mm... 2 It can improve the structural strength of the elastic zone, which helps to alleviate the phenomenon of insufficient support strength of the elastic zone between the main body area and the connecting 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. It can also improve the flow capacity of the elastic zone, which helps to improve the flow guiding effect and flow guiding requirements of the first current collector.

[0080] In some embodiments, 2mm ≤ W ≤ 10mm.

[0081] In the above technical solution, by setting the width of the projection of the elastic zone of the first current collector in the thickness direction of the first wall to 2mm to 10mm, on the one hand, setting the width of the projection of the elastic zone in the thickness direction of the first wall to be greater than or equal to 2mm can improve the flow capacity of the elastic zone, thereby improving the flow guiding effect of the first current collector and improving the structural strength of the elastic zone. This helps to alleviate the phenomenon of insufficient support strength of the elastic zone between the main body area and the connecting 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 elastic zone in the thickness direction of the first wall to be less than or equal to 10mm can effectively improve the ability of the elastic zone to deform when the main body area and the connecting area move closer or further away from each other along the thickness direction of the first wall. This allows the elastic zone to play a better buffering role between the main body area and the connecting area, thereby reducing the rigid pulling phenomenon between the main body area and the connecting area, between the main body area and the electrode assembly, and between the connecting area and the protrusion during the shaking or displacement of the electrode assembly.

[0082] In some embodiments, 3mm ≤ W ≤ 5mm.

[0083] In the above technical solution, by further setting the width of the projection of the elastic zone of the first current collector in the thickness direction of the first wall to 3mm to 5mm, on the one hand, setting the width of the projection of the elastic zone in the thickness direction of the first wall to be greater than or equal to 3mm can further improve the flow capacity of the elastic zone, thereby further improving the flow guiding effect of the first current collector and further improving the structural strength of the elastic zone. This helps to further alleviate the phenomenon of insufficient support strength of the elastic zone between the main body area and the connecting 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 elastic zone in the thickness direction of the first wall to be less than or equal to 5mm can further improve the ability of the elastic zone to deform when the main body area and the connecting area move closer or further away from each other along the thickness direction of the first wall, thereby improving the buffering effect of the elastic zone between the main body area and the connecting area. This can further reduce the rigid pulling phenomenon between the main body area and the connecting area, between the main body area and the electrode assembly, and between the connecting area and the protrusion during the process of the electrode assembly shaking or shifting.

[0084] In some embodiments, the thickness of the elastic region is T2, which satisfies 0.15mm≤T2≤0.8mm.

[0085] In the above technical solution, by setting the thickness of the elastic zone of the docking part to 0.15mm to 0.8mm, on the one hand, setting the thickness of the elastic zone to be greater than or equal to 0.15mm can improve the flow capacity of the elastic zone, thereby improving the flow guiding effect of the first current collector and improving the structural strength of the elastic zone. This helps to alleviate the phenomenon of insufficient support strength of the elastic zone between the main body area and the connecting 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 thickness of the elastic zone to be less than or equal to 0.8mm can effectively improve the ability of the elastic zone to deform when the main body area and the connecting area move closer or further away from each other along the thickness direction of the first wall. This allows the elastic zone to play a better buffering role between the main body area and the connecting area, thereby reducing the rigid pulling phenomenon between the main body area and the connecting area, between the main body area and the electrode assembly, and between the connecting area and the protrusion during the shaking or displacement of the electrode assembly. It can also save the space occupied by the elastic zone in the thickness direction of the first wall, which is beneficial to improving the internal space utilization rate of the cylindrical battery cell.

[0086] In some embodiments, 0.3mm ≤ T2 ≤ 0.5mm.

[0087] In the above technical solution, by further setting the thickness of the elastic zone of the docking part to 0.3mm to 0.5mm, on the one hand, setting the thickness of the elastic zone to be greater than or equal to 0.3mm can further improve the flow capacity of the elastic zone, thereby further improving the flow guiding effect of the first current collector and further improving the structural strength of the elastic zone. This helps to further alleviate the phenomenon of insufficient support strength of the elastic zone between the main body area and the connecting 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 elastic zone to be less than or equal to 0.5mm can further improve the ability of the elastic zone to deform when the main body area and the connecting area move closer or further away from each other along the thickness direction of the first wall, thereby further improving the buffering effect of the elastic zone between the main body area and the connecting area. This can further reduce the rigid pulling phenomenon between the main body area and the connecting area, between the main body area and the electrode assembly, and between the connecting area and the protrusion during the process of the electrode assembly shaking or shifting. It can also further save the space occupied by the elastic zone in the thickness direction of the first wall, which is conducive to further improving the internal space utilization rate of the cylindrical battery cell.

[0088] In some embodiments, the thickness of the elastic region is less than the thickness of the main body region; and / or, the thickness of the elastic region is less than the thickness of the connection region.

[0089] In the above technical solution, by setting the thickness of the elastic 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 elastic zone to deform when the main body zone and the connecting zone move closer or further apart along the thickness direction of the first wall is improved. This allows the elastic zone to play a better buffering role between the main body zone and the connecting zone. Similarly, by setting the thickness of the elastic zone to be less than the thickness of the connecting zone, the manufacturing cost and difficulty of the first current collector component are reduced, while the ability of the elastic zone to deform when the main body zone and the connecting zone move closer or further apart along the thickness direction of the first wall is improved. This allows the elastic zone to play a better buffering role between the main body zone and the connecting zone.

[0090] In some embodiments, along the thickness direction of the first wall, the connection area is disposed on the side of the protrusion opposite to the electrode assembly and connected to the protrusion.

[0091] In the above technical solution, by setting the connection area of ​​the docking part of the first current collector to be located on the side of the protrusion away from the electrode assembly in the thickness direction of the first wall, the connection area and the main body are respectively located on both sides of the protrusion in the thickness direction of the first wall, and the connection area and the side of the protrusion away from the electrode assembly are connected to each other. The cylindrical battery cell with this structure can, on the one hand, realize that the first current collector and the protrusion can share part of the space in the thickness direction of the first wall, which is conducive to improving the internal space utilization of the cylindrical battery cell and thus improving the energy density of the cylindrical battery cell. On the other hand, it can realize that the assembly connection between the connection area and the protrusion is not affected by the interference of the electrode assembly, which is conducive to reducing the assembly difficulty of the connection area of ​​the docking part and the protrusion, and can also help optimize the production process of the cylindrical battery cell.

[0092] In some embodiments, along the radial direction of the cylindrical battery cell, a groove is formed on the side of the sidewall facing away from the electrode assembly and corresponding to the position of the protrusion.

[0093] In the above technical solution, by forming a groove on the side of the sidewall facing away from the electrode assembly and at the corresponding protrusion position, the protrusion formed on the side of the sidewall facing the electrode assembly can be a structure that can be formed by stamping. This allows for the formation of a protrusion on the side of the sidewall facing the electrode assembly and a groove on the other side at the corresponding protrusion position. Cylindrical battery cells with this structure can reduce the difficulty of forming a protrusion on the side of the sidewall facing the electrode assembly, which is beneficial to improving the production efficiency of cylindrical battery cells. On the other hand, it can make the interior of the protrusion a hollow structure, which allows the protrusion to have the ability to elastically deform, which helps to alleviate the rigid tension between the docking part and the protrusion, thereby reducing the risk of connection failure between the docking part and the protrusion.

[0094] In some embodiments, the housing further includes a second wall; the second wall and the first wall are disposed opposite to each other in the thickness direction of the first wall, the second wall is integrally formed with the side wall, one end of the side wall is connected to the second wall along the thickness direction of the first wall, and the other end is enclosed to form an opening, the side wall and the second wall together define a receiving cavity, and the electrode assembly is received in the receiving cavity; wherein, the first wall closes the opening.

[0095] In the above technical solution, by setting the side wall of the outer shell to form an opening at the end away from the second wall in the thickness direction of the first wall, and the first wall being a closed opening structure, the first current collector is a structure set on the side of the electrode assembly facing the opening in the thickness direction of the first wall. This reduces the difficulty of assembling the support area of ​​the body of the first current collector between the electrode assembly and the protrusion, and also reduces the connection difficulty between the docking part and the protrusion. This reduces the assembly difficulty of the cylindrical battery cell, optimizes the production process of the cylindrical battery cell, and helps to improve the production efficiency of the cylindrical battery cell.

[0096] In some embodiments, the sidewall is bent at one end away from the second wall in the thickness direction of the first wall to form a flange, the flange enclosing the opening; wherein, along the thickness direction of the first wall, a portion of the first wall is located between the flange and the protrusion, the flange and the protrusion being configured to cooperate in clamping the first wall.

[0097] In the above technical solution, by bending the side wall away from the second wall along the thickness direction of the first wall to form a flange, and setting a portion of the first wall in the thickness direction of the first wall between the protrusion and the flange, the protrusion and the flange can also play a role in assembling and fixing the first wall, so as to realize the assembly between the first wall and the side wall. The cylindrical battery cell with this structure can reduce the assembly difficulty between the first wall and the side wall, thereby improving the production efficiency of the cylindrical battery cell.

[0098] 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 first wall of the cylindrical battery cell, and the seal is configured to seal the gap between the first wall and the sidewall.

[0099] 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 first wall, the sealing element can seal the gap between the first wall 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.

[0100] In some embodiments, the sidewall is integrally formed with the first wall, and one end of the sidewall is connected to the first wall along the thickness direction of the first wall, while the other end forms an opening. The sidewall and the first wall together define a receiving cavity, and the electrode assembly is received in the receiving cavity. The housing further includes a second wall, which is disposed opposite to the first wall in the thickness direction of the first wall, and the second wall closes the opening.

[0101] In the above technical solution, by setting the first wall and the side wall as an integrally formed structure, and the side wall encloses the end of the first wall away from the first wall in the thickness direction to form an opening for assembling the electrode assembly, and the second wall closes the opening, the cylindrical battery cell with this structure can first form a protrusion on the inner circumferential surface of the side wall and then assemble the electrode assembly into the receiving cavity formed by the side wall and the first wall. This helps to reduce the damage to the electrode assembly caused by the protrusion during the forming process, thereby improving the production quality of the cylindrical battery cell.

[0102] In some embodiments, the protrusion is a ring-shaped structure extending circumferentially along the sidewall.

[0103] In the above technical solution, by setting the protrusion as a ring structure with the ends connected, on the one hand, the support effect of the protrusion on the electrode assembly through the first current collector can be improved, and on the other hand, the protrusion can be connected to the docking part at any position in its circumferential direction, which helps to reduce the positioning difficulty and assembly difficulty between the docking part and the protrusion.

[0104] In some embodiments, the pressure relief groove is an annular structure extending circumferentially along the sidewall.

[0105] In the above technical solution, by setting the pressure relief groove as a ring structure with the ends connected, the cylindrical battery cell can completely open up the area where the pressure relief component is located in the pressure relief groove when the pressure is relieved, which is beneficial to increase the pressure relief area of ​​the cylindrical battery cell and thus increase the pressure relief rate of the cylindrical battery cell.

[0106] In some embodiments, the pressure relief component is integrally formed with the first wall.

[0107] In the above technical solution, by setting the pressure relief component as an integral part of the first wall, the pressure relief component becomes part of the first wall, and the pressure relief groove is directly set on the first wall. This eliminates the need for the assembly process of the pressure relief component and the first wall, which helps to optimize the processing technology of cylindrical battery cells and improve the production efficiency of cylindrical battery cells.

[0108] In some embodiments, the pressure relief component is separately disposed from the first wall, and the pressure relief component is connected to the first wall.

[0109] In the above technical solution, by setting the pressure relief component as a separate structure from the first wall, the difficulty of directly machining the pressure relief groove on the first wall can be reduced, and the impact on the structural strength of the first wall can be reduced.

[0110] Secondly, embodiments of this application also provide a battery device, including the aforementioned cylindrical battery cell.

[0111] 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

[0112] 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.

[0113] Figure 1 is a structural schematic diagram of a vehicle provided in some embodiments of this application;

[0114] Figure 2 is an exploded view of the structure of a battery device provided in some embodiments of this application;

[0115] Figure 3 is a schematic diagram of the structure of a cylindrical battery cell provided in some embodiments of this application;

[0116] Figure 4 is an exploded view of the structure of a cylindrical battery cell provided in some embodiments of this application;

[0117] Figure 5 is a cross-sectional view of a cylindrical battery cell provided in some embodiments of this application;

[0118] Figure 6 is a partial enlarged view of point A of the cylindrical battery cell shown in Figure 5;

[0119] Figure 7 is a partial cross-sectional view of the housing provided in some embodiments of this application;

[0120] Figure 8 is a schematic diagram of the structure of the first current collection component provided in some embodiments of this application;

[0121] Figure 9 is a front view of the first flow collection member provided in some embodiments of this application in the thickness direction of the first wall;

[0122] Figure 10 is a schematic diagram of the structure of the first connecting part, the second connecting part and the third connecting part on the first current collector provided in some embodiments of this application.

[0123] Icons: 1000 - Vehicle; 100 - Battery assembly; 10 - Housing; 11 - First housing body; 12 - Second housing body; 20 - Cylindrical battery cell; 21 - Casing; 211 - First wall; 2111 - Pressure relief groove; 212 - Side wall; 2121 - Protrusion; 2122 - Opening; 2123 - Groove; 2124 - Flanged edge; 213 - Second wall; 214 - Receiving cavity; 2141 - First cavity; 2142 - Second cavity; 22 - Electrode assembly; 221 - Main body; 222 - First electrode tab; 223 - Second electrode tab; 224-Central through hole; 23-First current collector; 231-Body part; 2311-Main body area; 2311a-Exhaust hole; 2312-Support area; 232-Dating part; 2321-Connection area; 2322-Elastic area; 2322a-Bending section; 234-Exhaust gap; 24-Electrode terminal; 25-Second current collector; 26-First connection part; 27-Second connection part; 28-Third connection part; 29-Seal; 200-Controller; 300-Motor; X-Thickness direction of the first wall. Detailed Implementation

[0124] 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.

[0125] 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.

[0126] 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.

[0127] 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.

[0128] 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.

[0129] 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.

[0130] In this application, "multiple" means two or more (including two).

[0131] 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.

[0132] 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.

[0133] 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.

[0134] 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.

[0135] 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.

[0136] 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.).

[0137] 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 / 3 O2 (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 0.05At least one of O2 and its modified compounds.

[0138] 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.

[0139] In some embodiments, the negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector.

[0140] 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.).

[0141] 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.

[0142] 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.

[0143] 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.

[0144] In some embodiments, the positive current collector can be made of aluminum, and the negative current collector can be made of copper.

[0145] In some embodiments, the electrode assembly further includes an isolator disposed between the positive and negative electrodes.

[0146] 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.

[0147] 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.

[0148] 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.

[0149] 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.

[0150] 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.

[0151] 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.

[0152] Among them, the gel electrolyte includes a polymer as the electrolyte backbone network, combined with an ionic liquid - lithium salt.

[0153] Solid electrolytes include polymer solid electrolytes, inorganic solid electrolytes, and composite solid electrolytes.

[0154] 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.

[0155] 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.

[0156] As an example, composite solid electrolytes are formed by adding inorganic solid electrolyte fillers to polymer solid electrolytes.

[0157] In some implementations, the electrode assembly has a wound structure. The positive and negative electrode sheets are wound into a wound structure.

[0158] In some embodiments, the electrode assembly can be cylindrical, flat, or polygonal, etc.

[0159] In some implementations, the electrode assembly has a positive tab and a negative tab.

[0160] 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.

[0161] As an example, a single battery cell can be cylindrical, i.e., a cylindrical battery cell.

[0162] 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.

[0163] 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.

[0164] 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.

[0165] 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.

[0166] As an example, battery cell assemblies can also be housed in a housing by directly fixing multiple battery cells to the housing.

[0167] 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 closing, which can be either sealed or unsealed. The first enclosure body may be a top cover or a bottom plate.

[0168] 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.

[0169] 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.

[0170] 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.

[0171] 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.

[0172] For a typical cylindrical battery cell, the cylindrical battery cell includes a casing and an electrode assembly housed within the casing. One tab of the electrode assembly is electrically connected to the casing, so that the casing serves as an output electrode of the cylindrical battery cell. Correspondingly, the casing of the cylindrical battery cell is usually provided with a pressure relief structure, which can crack when the cylindrical battery cell experiences thermal runaway, thereby releasing the internal pressure of the cylindrical battery cell and thus helping to ensure the safety of the cylindrical battery cell in use. In related technologies, to reduce the difficulty of electrical connection between electrode components and the casing, a current collector is usually set inside the casing. The current collector connects the electrode tabs of the electrode components to the casing to achieve electrical connection between the electrode components and the casing. However, when a cylindrical battery cell with this structure experiences thermal runaway, the current collector inside the casing will obstruct the internal exhaust path or pressure relief structure of the cylindrical battery cell. It is also not conducive to the active material of the electrode components being ejected from the outside of the casing through the pressure relief structure. As a result, the pressure relief rate of the cylindrical battery cell during thermal runaway is low, which makes the cylindrical battery cell susceptible to fire, explosion or connection failure due to untimely pressure relief. This leads to low reliability of the cylindrical battery cell.

[0173] Based on the above considerations, in order to solve the problem of low reliability of cylindrical battery cells, this application provides a cylindrical battery cell, which includes a casing, an electrode assembly, and a first current collector. The casing includes a first wall and a side wall. The thickness direction of the first wall is the axial direction of the cylindrical battery cell. A pressure relief groove is provided on the first wall. The side wall surrounds the first wall, and a protrusion is provided on the inner circumferential surface of the side wall. Both the protrusion and the pressure relief groove extend circumferentially along the side wall. The electrode assembly is housed in the casing and is located on the side of the protrusion facing away from the first wall. The first current collector includes a body portion and a docking portion. The body portion is located on the side of the electrode assembly facing the first wall and is connected to the electrode assembly. The body portion includes a main body area and a plurality of support areas connected to the outer circumferential surface of the main body area. The plurality of support areas are spaced apart circumferentially along the main body area. At least a portion of the support areas is located between the electrode assembly and the protrusion in the thickness direction of the first wall. The docking portion is connected to the main body area and connected to the protrusion to electrically connect the electrode assembly and the side wall. Along the radial direction of the cylindrical battery cell, the inner diameter of the protrusion is D1, the outer diameter of the main body area is D2, and the inner diameter of the pressure relief groove is D3, satisfying that D1≥D2 and D3≥0.75D2.

[0174] In this type of cylindrical battery cell, the first current collector has a body and a docking portion. The body is located on the side of the electrode assembly facing the first wall in the thickness direction of the first wall and is connected to the electrode assembly. The docking portion connects the body and the protrusion to achieve electrical connection between the electrode assembly and the side wall through the first current collector. The body includes a main body region and multiple support regions connected to the outer peripheral surface of the main body region. The multiple support regions are spaced apart circumferentially along the main body region, and at least a portion of the support regions is located between the electrode assembly and the protrusion in the thickness direction of the first wall. This allows the body of the first current collector to support the electrode assembly between the protrusion and the electrode assembly while also allowing thermal runaway gas inside the cylindrical battery cell to be vented through the gaps between the multiple support regions. This improves the internal venting smoothness of the cylindrical battery cell and increases the depressurization rate of the cylindrical battery cell. The inner diameter of the protrusion is set to be greater than or equal to... The outer diameter of the main body area of ​​the main body is set to be greater than or equal to 0.75 times the outer diameter of the main body area of ​​the main body. This results in the main body area of ​​the main body being structured such that its projection in the thickness direction of the first wall is located inside the protrusion, and the pressure relief groove is structured such that its projection in the thickness direction of the first wall is located near the outer edge of the main body area or outside the main body area. This reduces the obstruction of the protrusion and the main body area to the exhaust path inside the cylindrical battery cell. This allows the thermal runaway gas inside the cylindrical battery cell to pass more smoothly through the gaps between multiple support areas into the side of the main body facing the first wall and then be directly released through the area with the pressure relief groove on the pressure relief component on the first wall. This effectively improves the smoothness of internal exhaust and the pressure relief rate of the cylindrical battery cell, which helps to reduce the risk of the cylindrical battery cell bursting or exploding due to untimely pressure relief, thereby improving the stability and reliability of the cylindrical battery cell in use.

[0175] 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 mitigate the problem of fires and explosions caused by untimely pressure release of cylindrical battery cells, thereby improving the reliability of the cylindrical battery cells.

[0176] 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.

[0177] 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.

[0178] 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.

[0179] 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.

[0180] 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.

[0181] 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.

[0182] 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.

[0183] 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.

[0184] 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.

[0185] 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.

[0186] According to some embodiments of this application, referring to Figure 3, and further referring to Figures 4, 5, 6, 7, 8, and 9, Figure 4 is an exploded view of the cylindrical battery cell 20 provided in some embodiments of this application; Figure 5 is a cross-sectional view of the cylindrical battery cell 20 provided in some embodiments of this application; Figure 6 is a partial enlarged view of point A of the cylindrical battery cell 20 shown in Figure 5; Figure 7 is a partial cross-sectional view of the housing 21 provided in some embodiments of this application; Figure 8 is a structural schematic diagram of the first current collector 23 provided in some embodiments of this application; and Figure 9 is a front view of the first current collector 23 provided in some embodiments of this application along the thickness direction X of the first wall. This application provides a cylindrical battery cell 20, which includes a housing 21, an electrode assembly 22, and a first current collector 23. The outer casing 21 includes a first wall 211 and a side wall 212. The thickness direction X of the first wall is the axial direction of the cylindrical battery cell 20. A pressure relief component is provided on the first wall 211, and the pressure relief component is provided with a pressure relief groove 2111. The side wall 212 surrounds the first wall 211, and a protrusion 2121 is provided on the inner circumferential surface of the side wall 212. Both the protrusion 2121 and the pressure relief groove 2111 extend circumferentially along the side wall 212. The electrode assembly 22 is accommodated within the outer casing 21 and is located on the side of the protrusion 2121 opposite to the first wall 211. The first current collector 23 includes a body portion 231 and a docking portion 232. The body portion 231 is located on the side of the electrode assembly 22 facing the first wall 211 and is connected to the electrode assembly 22. The body portion 231 includes a main body region 2311 and a plurality of support regions 2312 connected to the outer peripheral surface of the main body region 2311. The plurality of support regions 2312 are spaced apart circumferentially along the main body region 2311. At least a portion of the support regions 2312 is located between the electrode assembly 22 and the protrusion 2121 in the thickness direction X of the first wall. The docking portion 232 is connected to the main body region 2311 and connected to the protrusion 2121 to electrically connect the electrode assembly 22 and the side wall 212. Along the radial direction of the cylindrical battery cell 20, the inner diameter of the protrusion 2121 is D1, the outer diameter of the main body region 2311 is D2, and the inner diameter of the pressure relief groove 2111 is D3, satisfying that D1≥D2 and D3≥0.75D2.

[0187] 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.

[0188] In this embodiment of the application, the outer casing 21 may include a first wall 211, a second wall 213 and a side wall 212. The side wall 212 is a structure surrounding the first wall 211 and the second wall 213. The first wall 211 and the second wall 213 are arranged opposite to each other along the thickness direction X of the first wall, that is, the first wall 211 and the second wall 213 are arranged opposite to each other along the axial direction of the cylindrical battery cell 20. The two ends of the side wall 212 in the thickness direction X of the first wall are respectively connected to the first wall 211 and the second wall 213, so that the first wall 211 and the second wall 213 are the end walls of the outer casing 21 at both ends in the thickness direction X of the first wall.

[0189] Optionally, the structure of the outer casing 21 can be varied. For example, the outer casing 21 can be integrally formed with the first wall 211 and the side wall 212, with the side wall 212 forming an opening 2122 at the end away from the first wall 211 in the thickness direction X of the first wall, and the second wall 213 covering the opening 2122 of the side wall 212 to form a sealed connection, thereby forming a sealed space for accommodating the electrode assembly 22 and the electrolyte; the outer casing 21 can also be integrally formed with the second wall 213 and the side wall 212, with the side wall 212 being away from the second wall 213 in the thickness direction X of the first wall. One end is enclosed to form an opening 2122, and the first wall 211 covers the opening 2122 of the side wall 212 and forms a sealed connection to form a sealed space for accommodating the electrode assembly 22 and the electrolyte; the outer shell 21 may also have openings 2122 formed at both ends of the side wall 212 in the thickness direction X of the first wall, so that the side wall 212 is a hollow structure with openings 2122 formed at both ends of the thickness direction X of the first wall, and the first wall 211 and the second wall 213 respectively cover the openings 2122 at both ends of the side wall 212 in the thickness direction X of the first wall.

[0190] For example, in Figures 4, 5 and 6, the second wall 213 and the side wall 212 are integrally formed, and the side wall 212 surrounds the end of the first wall away from the second wall 213 in the thickness direction X to form an opening 2122. The first wall 211 covers the opening 2122 of the side wall 212 and forms a sealed connection to form a sealed space for accommodating the electrode assembly 22 and the electrolyte. The electrode assembly 22 is located on the side of the protrusion 2121 away from the first wall 211 in the thickness direction X of the first wall, such that the electrode assembly 22 is located between the protrusion 2121 and the second wall 213 in the thickness direction X of the first wall.

[0191] The cylindrical battery cell 20 is cylindrical, and its central axis extends along the thickness direction X of the first wall. In other words, the cylindrical battery cell 20 has a cylindrical structure, and its height is along the thickness direction X of the first wall, making its projection onto the thickness direction X of the first wall circular. Correspondingly, the side wall 212 of the outer casing 21 is also cylindrical, and its central axis extends along the thickness direction X of the first wall, making the projections of both the first wall 211 and the second wall 213 onto the thickness direction X of the first wall circular. That is, both the first wall 211 and the second wall 213 have a disc-shaped structure.

[0192] It should be noted that the thickness direction X of the first wall is perpendicular to the radial direction of the cylindrical battery cell 20. The radial direction of the cylindrical battery cell 20 is the direction in which the central axis of the cylindrical battery cell 20 points to the outer peripheral surface of the cylindrical battery cell 20 or the direction in which the outer peripheral surface of the cylindrical battery cell 20 points to the central axis of the cylindrical battery cell 20 in the projection plane perpendicular to the thickness direction X of the first wall.

[0193] A protrusion 2121 is provided on the inner circumferential surface of the sidewall 212. That is, the protrusion 2121 is a convex hull structure protruding on the side of the sidewall 212 facing the electrode assembly 22. The protrusion 2121 extends circumferentially along the sidewall 212. In other words, the protrusion 2121 can be an arc structure or annular structure extending circumferentially along the sidewall 212. For example, the protrusion 2121 is an annular structure extending circumferentially along the sidewall 212, that is, the protrusion 2121 is an annular structure coaxial with the cylindrical battery cell 20.

[0194] A pressure relief component is provided on the first wall 211. The pressure relief component is provided with a pressure relief groove 2111. The pressure relief component is configured to be able to crack along at least a portion of the pressure relief groove 2111 when the cylindrical battery cell 20 is depressurized, so as to release the internal pressure of the cylindrical battery cell 20. That is, the pressure relief component on the first wall 211 forms a weak structure for pressure relief in the area where the pressure relief groove 2111 is provided, so that when the cylindrical battery cell 20 experiences thermal runaway and releases internal pressure, at least a portion of the area where the pressure relief component on the first wall 211 is provided with the pressure relief groove 2111 can crack, thereby allowing at least a portion of the pressure relief component located on the inner circumferential side of the pressure relief groove 2111 to be opened and release the internal pressure of the cylindrical battery cell 20.

[0195] It should be noted that the pressure relief component and the first wall 211 can be integrally formed or separately configured. For example, in Figure 6, the pressure relief component and the first wall 211 are integrally formed, with the pressure relief component being a part of the first wall 211. This allows the pressure relief groove 2111 to be directly disposed on the first wall 211. In other words, the first wall 211 is configured to at least partially split along the pressure relief groove 2111 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 first wall 211 can also be separately configured. Correspondingly, the pressure relief component can be connected to the first wall 211 by means of welding or other structures.

[0196] The pressure relief groove 2111 extends circumferentially along the side wall 212. The pressure relief groove 2111 can be an arc structure or an annular structure extending circumferentially along the side wall 212. For example, the pressure relief groove 2111 is an annular structure extending circumferentially along the side wall 212, that is, the pressure relief groove 2111 is an annular groove structure coaxial with the cylindrical battery cell 20.

[0197] 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 FIG. 4, the electrode assembly 22 may include a positive electrode, a separator, and a negative electrode. The main body 221 of the electrode assembly 22 is a wound structure formed by winding the positive electrode portion, the separator portion, and the negative electrode portion. The main body 221 of the electrode assembly 22 has a cylindrical structure, and the central axis of the main body 221 of the electrode assembly 22 extends along the thickness direction X of the first wall.

[0198] 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.

[0199] 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.

[0200] The first electrode 222 and the second electrode 223 have opposite polarities. In Figures 4 and 5, the first electrode 222 and the second electrode 223 are respectively connected to the two ends of the main body 221 in the thickness direction X of the first wall. The first electrode 222 is located at the end of the main body 221 facing the first wall 211 and is electrically connected to the first current collector 23. The second electrode 223 is located at the end of the main body 221 facing the second wall 213.

[0201] 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 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.

[0202] In this embodiment of the application, the first current collector 23 serves to electrically connect the electrode assembly 22 and the protrusion 2121. The material of the first current collector 23 can be various, such as copper, iron, aluminum, steel or aluminum alloy.

[0203] The first current collector 23 includes a body portion 231 and a docking portion 232. The body portion 231 is the part of the first current collector 23 located on the side of the electrode assembly 22 facing the first wall 211 in the thickness direction X of the first wall and connected to the first electrode tab 222. The docking portion 232 is the part of the first current collector 23 that connects the body portion 231 and the protrusion 2121 to realize the electrical connection between the electrode assembly 22 and the side wall 212.

[0204] Optionally, the connection structure between the body portion 231 and the first electrode tab 222 can be various, such as adhesive bonding or welding. Similarly, the connection structure between the mating portion 232 and the protrusion 2121 can also be various, such as adhesive bonding or welding. For example, the body portion 231 is welded to the first electrode tab 222, and the connecting portion is welded to the protrusion 2121.

[0205] For example, the body portion 231 of the first current collector 23 is located between the electrode assembly 22 and the protrusion 2121 in the thickness direction X of the first wall to support the electrode assembly 22.

[0206] The main body 231 includes a main body region 2311 and a plurality of support regions 2312 connected to the outer peripheral surface of the main body region 2311. The plurality of support regions 2312 are arranged at intervals along the circumference of the main body region 2311. That is, the main body 231 includes a main body region 2311 and a plurality of support regions 2312 arranged around the main body region 2311 along the circumference of the main body region 2311, and each support region 2312 is radially connected to the outer edge of the main body region 2311. It should be noted that the circumference of the main body region 2311 is also the circumference of the cylindrical battery cell 20, and also the circumference of the sidewall 212.

[0207] For example, in Figures 8 and 9, the body portion 231 includes four support areas 2312. The four support areas 2312 are evenly and spaced apart on the outer periphery of the main body portion 2311 along the circumference. Of course, in other embodiments, the number of support areas 2312 connected to the outer periphery of the main body portion 2311 can be two, three, five or six, etc.

[0208] At least a portion of the support region 2312 is located between the electrode assembly 22 and the protrusion 2121 in the thickness direction X of the first wall. That is, at least a portion of the support region 2312 extends radially along the cylindrical battery cell 20 between the electrode assembly 22 and the protrusion 2121, such that at least a portion of the support region 2312 is located between the electrode assembly 22 and the protrusion 2121 in the thickness direction X of the first wall.

[0209] For example, in FIG6, the support region 2312 is located only partially between the electrode assembly 22 and the protrusion 2121 in the thickness direction X of the first wall. Of course, in other embodiments, the support region 2312 may also be located entirely between the electrode assembly 22 and the protrusion 2121 in the thickness direction X of the first wall.

[0210] The docking portion 232 is connected to the main body region 2311, meaning the docking portion 232 is a structure connected to the main body region 2311 of the main body portion 231. For example, in Figures 8 and 9, the docking portion 232 is connected to the outer peripheral surface of the main body region 2311. The docking portion 232 includes a connecting region 2321 and an elastic region 2322. The connecting region 2321 is located on the side of the main body region 2311 facing the first wall 211 in the thickness direction X of the first wall. The connecting region 2321 is connected to the protrusion 2121. The elastic region 2322 is connected between the connecting region 2321 and the main body region 2311 of the main body portion 2311. Correspondingly, the elastic region 2322 is connected to the outer peripheral surface of the main body region 2311. For example, the connecting region 2321 is welded to the protrusion 2121.

[0211] For example, the first collector component 23 is provided with a plurality of docking parts 232, all of which are connected to the protrusion 2121. The plurality of docking parts 232 are arranged at intervals along the circumference of the main body area 2311 and are all connected to the outer circumferential surface of the main body area 2311. The plurality of docking parts 232 and the plurality of support areas 2312 are alternately arranged in the circumferential direction of the main body area 2311, such that in the circumferential direction of the main body area 2311, a docking part 232 is provided between every two adjacent support areas 2312.

[0212] In this embodiment, along the radial direction of the cylindrical battery cell 20, the inner diameter of the protrusion 2121 is D1, that is, D1 is the diameter of the circle containing the inner contour of the orthographic projection of the protrusion 2121 in the projection plane perpendicular to the thickness direction X of the first wall. Along the radial direction of the cylindrical battery cell 20, the outer diameter of the main body region 2311 is D2, that is, D2 is the diameter of the circle containing the outer contour of the orthographic projection of the main body region 2311 in the projection plane perpendicular to the thickness direction X of the first wall. Along the radial direction of the cylindrical battery cell 20, the inner diameter of the pressure relief groove 2111 is D3, that is, D3 is the diameter of the circle containing the inner contour of the orthographic projection of the pressure relief groove 2111 in the projection plane perpendicular to the thickness direction X of the first wall.

[0213] D1≥D2, that is, in the projection plane perpendicular to the thickness direction X of the first wall, the orthographic projection of the main body area 2311 is located on the inner periphery of the orthographic projection of the protrusion 2121.

[0214] D3 ≥ 0.75D2, meaning that in the projection plane perpendicular to the thickness direction X of the first wall, the structure can have the edge portion of the orthographic projection of the main body region 2311 overlapping with the orthographic projection of the pressure relief groove 2111, or the orthographic projection of the main body region 2311 located on the inner periphery of the orthographic projection of the pressure relief groove 2111. Preferably, D3 ≥ D2, meaning that in the projection plane perpendicular to the thickness direction X of the first wall, the orthographic projection of the main body region 2311 is located on the inner periphery of the orthographic projection of the pressure relief groove 2111. Optionally, in some embodiments, D3 ≥ 0.85D2.

[0215] In some embodiments, as shown in Figures 3, 4 and 5, the cylindrical battery cell 20 may further include an electrode terminal 24. The electrode terminal 24 is insulatedly mounted on the second wall 213 of the housing 21. The electrode terminal 24 is electrically connected to the second tab 223, so that the electrode terminal 24 serves as another output electrode of the cylindrical battery cell 20. That is, the electrode terminal 24 can function as an input or output of electrical energy 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 24 and the housing 21.

[0216] The electrode terminal 24 is insulatedly mounted on the second wall 213 of the housing 21. That is, the electrode terminal 24 is mounted on the end of the housing 21 away from the first wall 211 in the thickness direction X of the first wall, and an insulating element is provided between the electrode terminal 24 and the second wall 213, so that no electrical connection is formed between the electrode terminal 24 and the housing 21.

[0217] Referring to Figure 5, the electrode terminal 24 is riveted to the second wall 213 of the housing 21. Specifically, the second wall 213 of the housing 21 has mounting holes that extend through both sides of the second wall 213 along the thickness direction X of the first wall. A portion of the electrode terminal 24 passes through these mounting holes. The electrode terminal 24 has a first clamping portion located on the side of the second wall 213 facing the electrode assembly 22 and a second clamping portion located on the side of the second wall 213 away from the electrode assembly 22. At least a portion of the second wall 213 is located between the first and second clamping portions along the thickness direction X of the first wall, allowing the first and second clamping portions to cooperate in clamping the second wall 213, thereby riveting the electrode terminal 24 to the second wall 213 of the housing 21. Of course, in other embodiments, the electrode terminal 24 can also be snap-fitted or glued to the second wall 213.

[0218] For example, the electrode terminal 24 can be made of various materials, such as copper, iron, aluminum, steel or aluminum alloy.

[0219] In some embodiments, as shown in Figures 4 and 5, the cylindrical battery cell 20 may further include a second current collector 25, which is disposed in the thickness direction X of the first wall between the second tab 223 of the electrode assembly 22 and the second wall 213 of the housing 21. The second current collector 25 connects the second tab 223 and the electrode terminal 24 to electrically connect the electrode assembly 22 and the electrode terminal 24.

[0220] Optionally, the connection structure between the second current collector 25 and the second electrode tab 223, and between the second current collector 25 and the electrode terminal 24, can be various, such as welding connection or bonding.

[0221] For example, the material of the second current collector 25 can be various, such as copper, iron, aluminum, steel or aluminum alloy.

[0222] 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 24, such as by welding or bonding.

[0223] In this embodiment, the first current collector 23 is provided with a body portion 231 and a docking portion 232. The body portion 231 is located on the side of the electrode assembly 22 facing the first wall 211 in the thickness direction X of the first wall and is connected to the electrode assembly 22. The docking portion 232 connects the body portion 231 and the protrusion 2121 to realize the electrical connection between the electrode assembly 22 and the side wall 212 through the first current collector 23. The body portion 231 includes a main body region 2311 and a plurality of support regions 2312 connected to the outer peripheral surface of the main body region 2311. The plurality of support regions 2312 are arranged along the periphery of the main body region 2311. The support areas 2312 are spaced apart, and at least a portion of the support area 2312 is located between the electrode assembly 22 and the protrusion 2121 in the thickness direction X of the first wall. This allows the body portion 231 of the first current collector 23 to support the electrode assembly 22 between the protrusion 2121 and the electrode assembly 22, while also enabling the thermal runaway gas inside the cylindrical battery cell 20 to be vented through the gaps between the multiple support areas 2312. This improves the smoothness of internal venting of the cylindrical battery cell 20 and increases the depressurization rate of the cylindrical battery cell 20. The inner diameter of the protrusion 2121 is set... The outer diameter of the main body region 2311 of the body portion 231 is greater than or equal to the outer diameter of the main body region 2311 of the body portion 231, and the inner diameter of the pressure relief groove 2111 is set to be greater than or equal to 0.75 times the outer diameter of the main body region 2311 of the body portion 231. This results in the main body region 2311 of the body portion 231 having a structure in which the projection of the first wall in the thickness direction X is located inside the protrusion 2121, and the pressure relief groove 2111 having a structure in which the projection of the first wall in the thickness direction X is located close to the outer edge of the main body region 2311 or located outside the main body region 2311. This reduces the impact of the protrusion 2121 and the main body region 2311 on the cylindrical electrical system. The obstruction of the exhaust path inside the cylindrical battery cell 20 allows the thermal runaway gas inside the cylindrical battery cell 20 to pass smoothly through the gaps between multiple support areas 2312 into the side of the main body 231 facing the first wall 211, and then be directly released through the area of ​​the pressure relief component on the first wall 211 with pressure relief grooves 2111. This effectively improves the smoothness of internal exhaust and pressure relief rate of the cylindrical battery cell 20, which helps to reduce the risk of the cylindrical battery cell 20 bursting or exploding due to untimely pressure relief, thereby improving the stability and reliability of the cylindrical battery cell 20 in use.

[0224] According to some embodiments of this application, as shown in Figures 6 and 7, D1 ≥ D3.

[0225] Where D1≥D3, that is, in the projection plane perpendicular to the thickness direction X of the first wall, the orthographic projection of the pressure relief groove 2111 is located on the inner periphery of the orthographic projection of the protrusion 2121. As shown in Figures 6, 7 and 9, in the embodiment where D3≥D2 and D1≥D2, at least a portion of the orthographic projection of the pressure relief groove 2111 is located between the orthographic projection of the protrusion 2121 and the orthographic projection of the main body region 2311 in the radial direction of the cylindrical battery cell 20.

[0226] In this embodiment, by setting the inner diameter of the protrusion 2121 to be greater than or equal to the inner diameter of the pressure relief groove 2111, the pressure relief groove 2111 is configured in the thickness direction X of the first wall to correspond to the gap between the protrusion 2121 and the main body area 2311 of the body portion 231. This further reduces the obstruction and blockage of the area of ​​the first wall 211 used for pressure relief by the protrusion 2121 and the main body area 2311, thereby further improving the internal venting smoothness and pressure relief rate of the cylindrical battery cell 20. This helps to further reduce the risk of the cylindrical battery cell 20 bursting or exploding due to untimely pressure relief, thereby further improving the stability and reliability of the cylindrical battery cell 20 in use.

[0227] According to some embodiments of this application, and in conjunction with Figures 6, 7 and 9, the outer diameter of the body portion 231 along the radial direction of the cylindrical battery cell 20 is D4, which satisfies D1≤0.95D4.

[0228] Among them, the outer diameter D4 of the main body 231 is: the diameter of the circle with radius from the end of the support area 2312 away from the main body area 2311 to the center of the main body area 2311 in the radial direction of the cylindrical battery cell 20, and also the diameter of the circle where the ends of the multiple support areas 2312 are located in the radial direction of the cylindrical battery cell 20 away from the main body area 2311.

[0229] D1≤0.95D4, meaning that the projection of the main body 221 of the first current collector 23 onto the thickness direction X of the first wall overlaps with the protrusion 2121. It should be noted that in embodiments where D1≥D2, the projection of the support area 2312 of the main body 231 onto the thickness direction X of the first wall overlaps with the protrusion 2121.

[0230] In this embodiment, by setting the inner diameter of the protrusion 2121 to be 0.95 times smaller than the outer diameter of the body portion 231, the projection of the inner circumferential surface of the protrusion 2121 onto the thickness direction X of the first wall is a structure located within the body portion 231. This allows the multiple support areas 2312 connected to the outer circumferential surface of the main body area 2311 of the body portion 231 to extend better between the electrode assembly 22 and the protrusion 2121, thereby improving the overlap effect between the multiple support areas 2312 and the protrusion 2121. This further enhances the support effect of the body portion 231 of the first current collector 23 on the electrode assembly 22, and also improves the effect of the body portion 231 of the first current collector 23 against the expansion of the electrode assembly 22 during the use of the cylindrical battery cell 20, thereby improving the stability of the cylindrical battery cell 20 in use.

[0231] According to some embodiments of this application, referring to FIG9, the maximum proportion of the plurality of support regions 2312 in the circumferential direction of the main body region 2311 is P, which satisfies 40% ≤ P ≤ 90%.

[0232] Among them, the maximum proportion P of multiple support areas 2312 in the circumferential direction of the main body area 2311 is: the maximum ratio of the sum of the arc lengths of multiple support areas 2312 intercepted by the same circle to the circumference of the corresponding circle among multiple circles with different radii centered at the center of the main body area 2311.

[0233] For example, the maximum proportion P of the multiple support areas 2312 in the circumferential direction of the main body area 2311 can be 40%, 42%, 45%, 48%, 50%, 52%, 55%, 58%, 60%, 62%, 65%, 68%, 70%, 72%, 75%, 78%, 80%, 82%, 85%, 88%, or 90%, etc.

[0234] In this embodiment, on the one hand, by setting the maximum proportion of the multiple support areas 2312 in the circumferential direction of the main body area 2311 to be greater than or equal to 40%, the maximum space occupied by the multiple support areas 2312 on their respective circumferences is greater than or equal to 40%, thereby improving the effect of the main body 231 overlapping with the protrusions 2121 through the multiple support areas 2312, thus improving the support effect of the main body 231 of the first current collector 23 on the electrode assembly 22, and also improving the effect of the main body 231 of the first current collector 23 on resisting the expansion of the electrode assembly 22 during the use of the cylindrical battery cell 20. On the other hand, by setting the maximum proportion of the multiple support areas 2312 in the circumferential direction of the main body area 2311 to be greater than or equal to 40%, the maximum space occupied by the multiple support areas 2312 on their respective circumferences is greater than or equal to 40%, thereby improving the effect of the main body 231 of the first current collector 23 on resisting the expansion of the electrode assembly 22. The maximum upward proportion is set to be less than or equal to 90%, so that the maximum space occupied by the multiple support areas 2312 on their respective circumferences is less than or equal to 90%. This can alleviate the phenomenon that the multiple support areas 2312 are too close together in the circumferential direction of the main body area 2311, thereby increasing the size of the gap between the multiple support areas 2312. This allows the thermal runaway gas inside the cylindrical battery cell 20 to enter the side of the main body 231 facing the first wall 211 more smoothly through the gap between the multiple support areas 2312. This can improve the smoothness of internal venting and the depressurization rate of the cylindrical battery cell 20, which is beneficial to reducing the risk of the cylindrical battery cell 20 bursting or exploding due to untimely depressurization.

[0235] In some embodiments, please continue to refer to Figure 9, the maximum proportion of the plurality of support regions 2312 in the circumferential direction of the main body region 2311 is P, which satisfies 50% ≤ P ≤ 80%.

[0236] In this embodiment, on the one hand, by further setting the maximum proportion of the multiple support areas 2312 in the circumferential direction of the main body area 2311 to be greater than or equal to 50%, the maximum space occupied by the multiple support areas 2312 on their respective circumferences is greater than or equal to 50%, thereby further improving the effect of the main body 231 overlapping with the protrusions 2121 through the multiple support areas 2312, thereby further improving the support effect of the main body 231 of the first current collector 23 on the electrode assembly 22, and further improving the effect of the main body 231 of the first current collector 23 on resisting the expansion of the electrode assembly 22 during the use of the cylindrical battery cell 20. On the other hand, by setting the maximum proportion of the multiple support areas 2312 in the circumferential direction of the main body area 2311 to be greater than or equal to 50%, the maximum space occupied by the multiple support areas 2312 on their respective circumferential direction is greater than or equal to 50%, thereby further improving the effect of the main body 231 of the first current collector 23 on resisting the expansion of the electrode assembly 22. The maximum proportion is further set to be less than or equal to 80%, so that the maximum space occupied by the multiple support areas 2312 on their respective circumferences is less than or equal to 80%. This can further alleviate the phenomenon that the multiple support areas 2312 are too close together in the circumferential direction of the main body area 2311, so as to further increase the size of the gap between the multiple support areas 2312. This allows the thermal runaway gas inside the cylindrical battery cell 20 to enter the side of the main body 231 facing the first wall 211 more smoothly through the gap between the multiple support areas 2312. This can further improve the smoothness of internal exhaust and pressure relief rate of the cylindrical battery cell 20, which is conducive to further reducing the risk of the cylindrical battery cell 20 bursting or exploding due to untimely pressure relief.

[0237] According to some embodiments of this application, in conjunction with Figures 6, 7 and 8, the protrusion 2121 protrudes radially from the inner circumferential surface of the sidewall 212 of the cylindrical battery cell 20 by a dimension of L1. In the projection plane perpendicular to the thickness direction X of the first wall, the portion overlapping the orthographic projection of the support area 2312 and the orthographic projection of the protrusion 2121 in the radial direction of the cylindrical battery cell 20 has a dimension of L2, satisfying 0.2L1≤L2≤0.9L1.

[0238] Wherein, L2 is the length of the portion of the support region 2312 projected in the thickness direction X of the first wall within the protrusion 2121 in the radial direction of the cylindrical battery cell 20, and is also the length of the support region 2312 extending radially from the cylindrical battery cell 20 to between the electrode assembly 22 and the protrusion 2121.

[0239] Optionally, 0.3L1≤L2≤0.8L1. For example, L2 can be 0.3 times, 0.31 times, 0.32 times, 0.33 times, 0.35 times, 0.38 times, 0.4 times, 0.42 times, 0.45 times, 0.48 times, 0.5 times, 0.52 times, 0.55 times, 0.58 times, 0.6 times, 0.62 times, 0.65 times, 0.68 times, 0.7 times, 0.72 times, 0.75 times, 0.78 times, or 0.8 times L1.

[0240] In this embodiment, by setting the size of the portion of the support area 2312 projected in the thickness direction X of the first wall and overlapping with the protrusion 2121 in the radial direction of the cylindrical battery cell 20 to 0.2 to 0.9 times the size of the protrusion 2121 protruding from the inner circumferential surface of the sidewall 212, the length of the support area 2312 extending radially from the cylindrical battery cell 20 to between the protrusion 2121 and the electrode assembly 22 is 0.2 to 0.9 times the size of the protrusion 2121 protruding from the inner circumferential surface of the sidewall 212. On the one hand, setting the length of the support area 2312 extending radially from the cylindrical battery cell 20 to between the protrusion 2121 and the electrode assembly 22 to be greater than or equal to 0.2 times the size of the protrusion 2121 protruding from the inner circumferential surface of the sidewall 212 can further improve the overlapping effect between the support area 2312 and the protrusion 2121, thereby further improving the support effect of the body portion 231 of the first current collector 23 on the electrode assembly 22. Furthermore, during the use of the cylindrical battery cell 20, the body portion 231 of the first current collector 23 can be further enhanced to resist the expansion of the electrode assembly 22. On the other hand, setting the length of the support area 2312 extending radially from the cylindrical battery cell 20 to the distance between the protrusion 2121 and the electrode assembly 22 to be less than or equal to 0.9 times the size of the protrusion 2121 protruding from the inner circumferential surface of the side wall 212 can alleviate the phenomenon of excessive overlap between the support area 2312 and the protrusion 2121, thereby reducing the difficulty of assembling the first current collector 23 into the housing 21. Moreover, when the cylindrical battery cell 20 is depressurized, the body portion 231 of the first current collector 23 can easily detach from the protrusion 2121 and the electrode assembly 22 under the impact of thermal runaway gas, which is beneficial to improving the internal exhaust smoothness and depressurization rate of the cylindrical battery cell 20, thereby further reducing the risk of the cylindrical battery cell 20 bursting or exploding due to untimely depressurization.

[0241] In some embodiments, as shown in FIG6, 2mm ≤ L1 ≤ 5mm. That is, the radial dimension of the protrusion 2121 in the cylindrical battery cell 20 is 2mm to 5mm, and optionally, 3mm ≤ L1 ≤ 4mm.

[0242] For example, the size L1 of the protrusion 2121 protruding radially from the inner circumferential surface of the sidewall 212 of the cylindrical battery cell 20 can be 2mm, 2.1mm, 2.2mm, 2.3mm, 2.4mm, 2.5mm, 2.8mm, 3mm, 3.2mm, 3.5mm, 3.8mm, 4mm, 4.2mm, 4.5mm, 4.6mm, 4.7mm, 4.8mm, 4.9mm, or 5mm, etc.

[0243] In this embodiment, by setting the size of the protrusion 2121 protruding from the inner circumferential surface of the sidewall 212 to 2mm to 5mm, the radial dimension of the protrusion 2121 in the cylindrical battery cell 20 is 2mm to 5mm. On the one hand, setting the size of the protrusion 2121 protruding from the inner circumferential surface of the sidewall 212 to be greater than or equal to 2mm can reduce the difficulty of the connection between the protrusion 2121 and the support area 2312, thereby reducing the difficulty of the body portion 231 of the first current collector 23 being disposed between the protrusion 2121 and the electrode assembly 22, and can improve the connection between the protrusion 2121 and the electrode. On the one hand, the support effect of component 22 is improved. On the other hand, setting the size of the protrusion 2121 protruding from the inner circumferential surface of the side wall 212 to less than or equal to 5mm can reduce the space occupied by the protrusion 2121 in the radial direction of the cylindrical battery cell 20. This helps to reduce the obstruction of the internal exhaust path of the protrusion 2121 to the cylindrical battery cell 20, thereby effectively improving the internal exhaust smoothness and pressure relief rate of the cylindrical battery cell 20. This helps to reduce the risk of the cylindrical battery cell 20 bursting or exploding due to untimely pressure relief, thereby improving the stability and reliability of the cylindrical battery cell 20 in use.

[0244] In some embodiments, as shown in Figures 6 and 8, L2 ≥ 1 mm. That is, in the radial direction of the cylindrical battery cell 20, the length of the support region 2312 extending between the electrode assembly 22 and the protrusion 2121 is greater than or equal to 1 mm.

[0245] For example, L2 can be 1mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, 1.6mm, 1.7mm or 1.8mm, etc.

[0246] In this embodiment, by setting the size of the portion of the projection of the support area 2312 on the thickness direction X of the first wall that overlaps with the protrusion 2121 in the radial direction of the cylindrical battery cell 20 to be greater than or equal to 1 mm, the length of the support area 2312 extending in the radial direction of the cylindrical battery cell 20 to the distance between the protrusion 2121 and the electrode assembly 22 is greater than or equal to 1 mm. This improves the overlapping effect between the support area 2312 and the protrusion 2121, thereby enhancing the support effect of the body portion 231 of the first current collector 23 on the electrode assembly 22. Furthermore, during the use of the cylindrical battery cell 20, the effect of the body portion 231 of the first current collector 23 on resisting the expansion of the electrode assembly 22 can be further improved.

[0247] According to some embodiments of this application, referring to FIG6, the thickness of the body portion 231 is T1, which satisfies 0.1mm≤T1≤0.6mm. Optionally, 0.2mm≤T1≤0.4mm.

[0248] Wherein, the thickness T1 of the body portion 231 is the thickness of the body portion 231 in the thickness direction X of the first wall. It should be noted that in the embodiment where the body portion 231 includes a main body region 2311 and a support region 2312, the thickness of both the main body region 2311 and the support region 2312 is 0.1 mm to 0.6 mm.

[0249] For example, the thickness T1 of the body portion 231 can be 0.1mm, 0.12mm, 0.15mm, 0.18mm, 0.2mm, 0.22mm, 0.25mm, 0.28mm, 0.3mm, 0.32mm, 0.35mm, 0.38mm, 0.4mm, 0.42mm, 0.45mm, 0.48mm, 0.5mm, 0.52mm, 0.55mm, 0.58mm, or 0.6mm, etc.

[0250] In this embodiment, setting the thickness of the body portion 231 to be greater than or equal to 0.1 mm can effectively improve the structural strength of the body portion 231, thereby enhancing the support effect of the body portion 231 on the electrode assembly 22 between the protrusion 2121 and the electrode assembly 22. Furthermore, during the use of the cylindrical battery cell 20, it can also improve the effect of the body portion 231 of the first current collector 23 against the expansion of the electrode assembly 22, which helps to reduce the risk of deformation or detachment of the body portion 231 under the expansion of the electrode assembly 22. On the other hand, setting the thickness of the body portion 231 to be less than or equal to 0.6 mm can reduce the manufacturing difficulty and cost of the body portion 231 of the first current collector 23, and can effectively reduce the space occupied by the body portion 231 in the thickness direction X of the first wall, which helps to improve the internal space utilization of the cylindrical battery cell 20.

[0251] According to some embodiments of this application, referring to Figures 6, 8, and 9, and further referring to Figure 10, Figure 10 is a structural schematic diagram of the first connecting portion 26, the second connecting portion 27, and the third connecting portion 28 on the first current collector 23 provided in some embodiments of this application. The electrode assembly 22 may include a main body portion 221 and a first electrode tab 222. Along the thickness direction X of the first wall, the first electrode tab 222 is connected to the end of the main body portion 221 facing the first wall 211. The main body region 2311 is welded to the first electrode tab 222 to form a plurality of first connecting portions 26, and a plurality of support regions 2312 are welded to the first electrode tab 222 to form a plurality of second connecting portions 27. The sum of the lengths of the plurality of second connecting portions 27 is greater than or equal to the sum of the lengths of the plurality of first connecting portions 26.

[0252] The first connecting part 26 and the second connecting part 27 are both strip structures. Correspondingly, the sum of the lengths of the multiple second connecting parts 27 is greater than or equal to the sum of the lengths of the multiple first connecting parts 26. In other words, the total length of the multiple second connecting parts 27 formed by welding the multiple support areas 2312 to the first electrode tab 222 is greater than or equal to the total length of the multiple first connecting parts 26 formed by welding the main body area 2311 to the first electrode tab 222.

[0253] It should be noted that the first connecting part 26 is the area where the main body region 2311 of the body part 231 and the first electrode 222 are welded together to form a fused area or a weld mark. Similarly, the second connecting part 27 is the area where the support region 2312 of the body part 231 and the first electrode 222 are welded together to form a fused area or a weld mark.

[0254] In this embodiment, the main body region 2311 of the body portion 231 is welded to the first electrode tab 222 to form a plurality of first connecting portions 26, and the plurality of support regions 2312 of the body portion 231 are welded to the first electrode tab 222 to form a plurality of second connecting portions 27. This results in both the main body region 2311 and the support regions 2312 being welded to the first electrode tab 222, thereby increasing the current-conducting area between the first electrode tab 222 and the body portion 231, and improving the connection stability and reliability between the body portion 231 of the first current collector 23 and the first electrode tab 222 of the electrode assembly 22. Furthermore, the outer ring length of the first electrode tab 222 is greater than the inner ring length of the first electrode tab 222. The current requirement of the outer ring of the first electrode 222 is greater than that of the inner ring of the first electrode 222. By setting the total length of the multiple second connecting parts 27 formed by welding multiple support areas 2312 to the first electrode 222 to be greater than the total length of the multiple first connecting parts 26 formed by welding the main body area 2311 to the first electrode 222, the current guiding area between the outer ring of the first electrode 222 and the main body 231 is greater than that between the inner ring of the first electrode 222 and the main body 231. This improves the current balance between the inner and outer rings of the first electrode 222 and helps to reduce the phenomenon of local lithium plating or increased internal resistance in the electrode assembly 22 during use.

[0255] In some embodiments, referring to Figures 9 and 10, a plurality of first connecting portions 26 are arranged circumferentially spaced along the sidewall 212, and the first connecting portions 26 extend radially along the cylindrical battery cell 20. That is, the plurality of first connecting portions 26 are arranged spaced around the central axis of the cylindrical battery cell 20, and the extension direction of each first connecting portion 26 is radial to the cylindrical battery cell 20, so that the plurality of first connecting portions 26 are arranged radially.

[0256] For example, the main body region 2311 is welded to the first electrode tab 222 to form four first connection portions 26. Of course, in other embodiments, the number of first connection portions 26 formed by welding the main body region 2311 to the first electrode tab 222 can also be two, three, five, six, seven or eight, etc.

[0257] In this embodiment, by welding the main body region 2311 and the first tab 222 together, the multiple first connecting parts 26 are arranged in a circumferentially spaced manner along the sidewall 212, and each first connecting part 26 is a structure extending radially along the cylindrical battery cell 20. On the one hand, this reduces the welding difficulty between the main body region 2311 and the first tab 222, and optimizes the layout of the multiple first connecting parts 26, which helps to alleviate the interference between the multiple first connecting parts 26. On the other hand, it enables the first tab 222 to be connected to the main body region 2311 at multiple positions in the circumferential direction of the sidewall 212, and also enables the first tab 222 to be connected to the main body region 2311 at multiple positions in the radial direction of the cylindrical battery cell 20. This allows the multiple rings of the first tab 222 to be connected to the main body region 2311, thereby increasing the current conduction area between the first tab 222 and the main body region 2311, and also improving the overcurrent balance between the electrode assembly 22 and the main body region 2311, so as to reduce the risk of local lithium plating in the electrode assembly 22 during use.

[0258] In some embodiments, as shown in Figures 9 and 10, a plurality of second connecting portions 27 are arranged circumferentially spaced along the sidewall 212, and the second connecting portions 27 extend radially along the cylindrical battery cell 20. That is, the plurality of second connecting portions 27 are arranged at intervals around the central axis of the cylindrical battery cell 20, and the extension direction of each second connecting portion 27 is radial to the cylindrical battery cell 20, so that the plurality of second connecting portions 27 are arranged radially.

[0259] In this embodiment, the multiple second connecting portions 27 formed by welding multiple support regions 2312 to the first electrode tab 222 are arranged in a circumferentially spaced manner along the sidewall 212, and each second connecting portion 27 is a structure extending radially along the cylindrical battery cell 20. This reduces the welding difficulty between the multiple support regions 2312 and the first electrode tab 222, optimizes the layout of the multiple second connecting portions 27, and helps to alleviate the interference between the multiple second connecting portions 27. On the other hand, it enables the first electrode tab 222 to achieve the desired effect. 2. The first tab 222 is connected to the support region 2312 at multiple positions in the circumferential direction of the side wall 212, and the first tab 222 is connected to the support region 2312 at multiple positions in the radial direction of the cylindrical battery cell 20. This allows the multi-ring structure of the first tab 222 to be connected to the support region 2312, thereby increasing the current conduction area between the first tab 222 and the support region 2312, and also improving the overcurrent balance between the electrode assembly 22 and the support region 2312, so as to reduce the risk of local lithium plating in the electrode assembly 22 during use.

[0260] In some embodiments, please continue to refer to Figures 9 and 10, each support region 2312 is welded to the first electrode tab 222 to form a second connection portion 27. That is, any one of the multiple support regions 2312 of the body portion 231 is welded to the first electrode tab 222 to form a second connection portion 27.

[0261] For example, each support region 2312 is welded to the first electrode tab 222 to form two second connection portions 27. Of course, in other embodiments, the number of second connection portions 27 formed by welding each support region 2312 to the first electrode tab 222 can also be one, three or four, etc.

[0262] In this embodiment, by welding each support region 2312 of the main body 231 to the first tab 222, multiple support regions 2312 arranged at intervals in the circumferential direction of the main body 2311 are all welded to the first tab 222 and correspondingly form a second connection portion 27. On the one hand, this can further improve the connection stability and reliability between the first tab 222 and the main body 231. On the other hand, it can realize that the first tab 222 is connected to multiple support regions 2312 in the circumferential direction of the sidewall 212, which is beneficial to improve the overcurrent balance between the electrode assembly 22 and the first current collector 23, so as to reduce the risk of local lithium plating in the electrode assembly 22 during use.

[0263] According to some embodiments of this application, referring to Figures 6, 8, and 9, the first current collecting member 23 includes a plurality of docking portions 232. The plurality of docking portions 232 are arranged at intervals along the circumference of the main body region 2311 and are all connected to the main body region 2311. The plurality of docking portions 232 are all connected to the protrusion 2121. That is, the body portion 231 of the first current collecting member 23 has a structure that is connected to the protrusion 2121 through the plurality of docking portions 232.

[0264] For example, in Figures 8 and 9, the first current collection member 23 is provided with four docking portions 232, and the four docking portions 232 are arranged at intervals along the circumference of the main body area 2311. Of course, in other embodiments, the number of docking portions 232 of the first current collection member 23 may also be two, three, five or six, etc.

[0265] In the embodiment where the docking portion 232 includes an elastic region 2322 and a connecting region 2321, the elastic regions 2322 of the plurality of docking portions 232 are all connected to the outer peripheral surface of the main body region 2311 and are arranged at intervals along the circumferential direction of the main body region 2311. Correspondingly, the connecting region 2321 of each docking portion 232 is connected to the protrusion 2121. It should be noted that the circumferential direction of the main body region 2311 is the circumferential direction of the cylindrical battery cell 20 and also the circumferential direction of the sidewall 212.

[0266] In this embodiment, the first current collector 23 is provided with a plurality of docking portions 232, and the plurality of docking portions 232 are arranged at intervals along the circumference of the main body area 2311 and are all connected to the protrusion 2121. This allows the protrusion 2121 to be connected to the docking portions 232 at multiple positions in the circumferential direction of the side wall 212. On the one hand, this can further improve the connection stability and reliability between the first current collector 23 and the protrusion 2121. On the other hand, it can further improve the flow guiding area between the first current collector 23 and the protrusion 2121, and further improve the flow balance between the first current collector 23 and the protrusion 2121, so as to reduce the risk of local temperature rise of the protrusion 2121.

[0267] According to some embodiments of this application, referring to Figures 6 and 10, multiple mating portions 232 are welded to protrusions 2121 and correspondingly form multiple third connecting portions 28. Each third connecting portion 28 corresponds to one of the mating portions 232 and extends circumferentially along the sidewall 212. In a projection plane perpendicular to the thickness direction X of the first wall, the outer edges of the orthographic projections of the multiple third connecting portions 28 are all located on the first circle, and the sum of the arc lengths of the outer edges of the orthographic projections of the multiple third connecting portions 28 is L3, and the circumference of the first circle is L4, satisfying L3 ≥ 0.5L4.

[0268] In this embodiment, the third connecting portion 28 corresponds one-to-one with the docking portion 232. The third connecting portion 28 extends circumferentially along the sidewall 212. That is, each docking portion 232 is welded to the protrusion 2121 to form a third connecting portion 28, and the third connecting portion 28 is an arc-shaped structure extending circumferentially along the sidewall 212. Correspondingly, multiple third connecting portions 28 formed by welding multiple docking portions 232 to the protrusion 2121 are arranged at intervals circumferentially along the sidewall 212. In the embodiment where the docking portion 232 includes an elastic region 2322 and a connecting region 2321, the connecting region 2321 is welded to the protrusion 2121 to form the third connecting portion 28. It should be noted that in other embodiments, there may be multiple third connecting portions 28 formed by welding each docking portion 232 to the protrusion 2121, and these multiple third connecting portions 28 are arranged at intervals circumferentially along the sidewall 212.

[0269] It should be noted that the third connecting part 28 is the area where the butt part 232 and the protrusion 2121 are welded together to form a fused area or a weld mark area.

[0270] L3 is the sum of the arc lengths of the outer contours of the projections of the third connecting parts 28 onto the thickness direction X of the first wall. Correspondingly, L4 is the circumference of the circle containing the outer contours of the projections of the third connecting parts 28 onto the thickness direction X of the first wall, i.e., the circumference of the first circle is L4.

[0271] L3≥0.5L4, that is, the proportion of the outer contour of the projection of the multiple third connecting parts 28 on the thickness direction X of the first wall on the first circle is greater than or equal to 50%.

[0272] For example, L3 can be 0.5 times, 0.51 times, 0.52 times, 0.53 times, 0.54 times, 0.55 times, 0.56 times, 0.57 times, 0.58 times, 0.59 times, 0.6 times, 0.61 times, 0.62 times, 0.63 times, 0.64 times, 0.65 times, 0.66 times, 0.67 times, 0.68 times, 0.69 times, 0.7 times, 0.71 times, 0.72 times, 0.73 times, 0.74 times, 0.75 times, 0.76 times, 0.77 times, 0.78 times, 0.79 times, 0.8 times, 0.81 times, 0.82 times, 0.83 times, 0.84 times, or 0.85 times of L4.

[0273] In this embodiment, by setting the sum of the arc lengths of the outer edges of the orthographic projections of the plurality of third connecting portions 28 in the thickness direction X of the first wall to be greater than or equal to 0.5 times the circumference of the first circle, the proportion of the plurality of third connecting portions 28 on the first circle is greater than or equal to 50%, thereby increasing the flow guiding area between the first current collecting member 23 and the protrusion 2121, thereby improving the flow guiding effect between the first current collecting member 23 and the outer shell 21, and thus reducing the phenomenon of increased internal resistance of the cylindrical battery cell 20 during use.

[0274] In some embodiments, L3 ≥ 0.8L4.

[0275] In this embodiment, by further setting the sum of the arc lengths of the outer edges of the orthographic projections of the plurality of third connecting portions 28 in the thickness direction X of the first wall to be greater than or equal to 0.8 times the circumference of the first circle, the proportion of the plurality of third connecting portions 28 on the first circle is greater than or equal to 80%, thereby further increasing the flow guiding area between the first current collecting member 23 and the protrusion 2121, so as to further improve the flow guiding effect between the first current collecting member 23 and the outer shell 21, which is beneficial to further reduce the phenomenon of increased internal resistance of the cylindrical battery cell 20 during use.

[0276] In some embodiments, as shown in Figures 6, 9 and 10, the mating portion 232 has a connection area 2321 that is welded to the protrusion 2121, and the connection area 2321 is an arcuate structure extending circumferentially along the sidewall 212.

[0277] In the projection plane perpendicular to the thickness direction X of the first wall, the sum of the arc lengths L3 of the outer edges of the orthographic projections of the plurality of third connecting portions 28 is less than or equal to the sum of the lengths of the connection areas 2321 of the plurality of docking portions 232 in the circumferential direction of the side wall 212. It should be noted that in the embodiment where the first collecting member 23 includes a plurality of docking portions 232, the connection areas 2321 of the plurality of docking portions 232 are arranged at intervals along the circumferential direction of the side wall 212.

[0278] In this embodiment, the docking part 232 is provided with a connection area 2321 for welding to the protrusion 2121. By setting the connection area 2321 as an arc-shaped structure extending circumferentially along the side wall 212, the connection area 2321 and the protrusion 2121 can fit together. On the one hand, it is convenient to weld the connection area 2321 of the docking part 232 to the protrusion 2121 to form a third connection part 28 extending circumferentially along the side wall 212, which helps to reduce the welding difficulty between the docking part 232 and the protrusion 2121. On the other hand, it can realize that the connection area 2321 can be welded to the protrusion 2121 at multiple positions in the circumferential direction of the side wall 212. This reduces the need to rotate and adjust the position of the first current collector 23 after it is assembled into the housing 21, further reducing the welding difficulty between the first current collector 23 and the protrusion 2121, thereby effectively improving the assembly efficiency of the cylindrical battery cell 20.

[0279] According to some embodiments of this application, as shown in Figures 8 and 9, multiple docking portions 232 are connected to the outer peripheral surface of the main body region 2311, and the docking portions 232 and the support regions 2312 are alternately arranged along the circumferential direction of the main body region 2311. That is, in the circumferential direction of the main body region 2311, a support region 2312 is provided between every two adjacent docking portions 232.

[0280] For example, in FIG9, the body portion 231 of the first current collection member 23 is provided with four support areas 2312, and correspondingly, the first current collection member 23 is provided with four docking portions 232. The four support areas 2312 and the four docking portions 232 are arranged alternately in the circumferential direction of the body portion 2311.

[0281] It should be noted that in the embodiment where the docking part 232 includes an elastic area 2322 and a connecting area 2321, the elastic area 2322 and the supporting area 2312 are arranged alternately and spaced apart in the circumferential direction of the main body area 2311. Correspondingly, the connecting areas 2321 of the multiple docking parts 232 are arranged around the main body area 2311 in the circumferential direction.

[0282] In this embodiment, by setting the multiple docking portions 232 arranged circumferentially along the main body region 2311 to be all connected to the outer peripheral surface of the main body region 2311, it is beneficial to reduce the connection difficulty between the main body region 2311 and the docking portions 232, thereby reducing the molding difficulty of the first current collector 23. In particular, by setting the docking portions 232 and the support region 2312 to be arranged alternately in the circumferential direction of the main body region 2311, on the one hand, the interference between the docking portions 232 and the support region 2312 can be reduced, thereby reducing the connection difficulty between the docking portions 232 and the protrusion 2121, and reducing the assembly difficulty between the body portion 231 and the electrode assembly 22. On the other hand, it can improve the regularity of the first current collector 23 and optimize the structural layout of the docking portions 232 and the support region 2312, thereby reducing the difficulty of assembling the first current collector 23 into the outer shell 21.

[0283] According to some embodiments of this application, referring to Figures 5 and 8, the electrode assembly 22 is provided with a central through hole 224, which penetrates both ends of the electrode assembly 22 along the thickness direction X of the first wall. The main body region 2311 is provided with an exhaust hole 2311a, which penetrates both sides of the main body region 2311 along the thickness direction X of the first wall and communicates with the central through hole 224. The projection of the hole wall surface of the central through hole 224 along the thickness direction X of the first wall is located within the exhaust hole 2311a.

[0284] The central through hole 224 is located at the center of the electrode assembly 22 and extends through both ends of the electrode assembly 22 along the thickness direction X of the first wall to allow internal gas flow and discharge. In an embodiment where the electrode assembly 22 includes a main body 221, a first tab 222, and a second tab 223, the central through hole 224 sequentially extends through the first tab 222, the main body 221, and the second tab 223 along the thickness direction X of the first wall.

[0285] Along the thickness direction X of the first wall, the projection of the hole wall surface of the central through hole 224 is located inside the vent hole 2311a. That is to say, the vent hole 2311a provided on the main body area 2311 of the body part 231 of the first flow collector 23 is a structure provided in the thickness direction X of the first wall corresponding to the central through hole 224, and the diameter of the vent hole 2311a is greater than or equal to the diameter of the central through hole 224.

[0286] In this embodiment, an exhaust hole 2311a is provided on the main body region 2311 of the body portion 231 of the first current collector 23, penetrating the main body region 2311 along the thickness direction X of the first wall. The exhaust hole 2311a is connected to the central through hole 224 of the electrode assembly 22, and the projection of the hole wall surface of the central through hole 224 in the thickness direction X of the first wall is set to be located inside the exhaust hole 2311a, so that the diameter of the exhaust hole 2311a is greater than or equal to the diameter of the central through hole 224, thereby achieving a circular structure. When thermal runaway occurs in the cylindrical battery cell 20, the thermal runaway gas in the central through hole 224 can enter the side of the body 231 facing the first wall 211 through the vent hole 2311a and be directly released through the area of ​​the pressure relief component on the first wall 211 with the pressure relief groove 2111. This helps to improve the smoothness of internal venting of the cylindrical battery cell 20, thereby effectively reducing the risk of the cylindrical battery cell 20 bursting or exploding due to untimely pressure relief, and improving the stability and reliability of the cylindrical battery cell 20 in use.

[0287] In some embodiments, as shown in FIG5, the diameter of the central through hole 224 is D5 and the diameter of the vent hole 2311a is D6, satisfying that D6≥1.5D5.

[0288] For example, the aperture D6 of the vent hole 2311a can be 1.5 times, 1.6 times, 1.7 times, 1.8 times, 1.9 times, 2 times, 2.1 times, 2.2 times, 2.3 times, 2.4 times, 2.5 times, or 2.6 times the aperture D5 of the center through hole 224.

[0289] In this embodiment, by further setting the diameter of the vent hole 2311a to be greater than or equal to 1.5 times the diameter of the central through hole 224, the smoothness of the thermal runaway gas in the central through hole 224 entering the side of the body 231 facing the first wall 211 through the vent hole 2311a can be further improved when thermal runaway occurs in the cylindrical battery cell 20. This is beneficial to further improve the internal venting smoothness of the cylindrical battery cell 20, thereby further reducing the risk of the cylindrical battery cell 20 bursting or exploding due to untimely pressure relief, and further improving the stability and reliability of the cylindrical battery cell 20 in use.

[0290] According to some embodiments of this application, referring to FIG9, the length of the support region 2312 along the radial direction of the cylindrical battery cell 20 is L5, satisfying 0.5D2≥L5. That is, the radius of the outer contour of the main body region 2311 is greater than or equal to the length of the support region 2312 in the radial direction of the cylindrical battery cell 20.

[0291] In this embodiment, by setting the radius of the main body region 2311 of the main body portion 231 to be greater than or equal to the length of the support region 2312 of the main body portion 231 protruding radially from the outer peripheral surface of the main body region 2311 of the cylindrical battery cell 20, the phenomenon of insufficient structural strength of the main body portion 231 caused by excessive space occupied by the support region 2312 in the main body portion 231 can be alleviated. This can further improve the poor support effect of the main body portion 231 on the electrode assembly 22 in the thickness direction X of the first wall, and further improve the effect of the main body portion 231 against the expansion of the electrode assembly 22 during the use of the cylindrical battery cell 20.

[0292] According to some embodiments of this application, referring to Figures 5 and 6, a receiving cavity 214 is formed inside the outer casing 21. The body portion 231 is configured to divide the receiving cavity 214 into a first cavity 2141 and a second cavity 2142 that are interconnected. The electrode assembly 22 is received in the first cavity 2141. The second cavity 2142 is located between the body portion 231 and the first wall 211 in the thickness direction X of the first wall. A pressure relief component is configured to be able to split at least a portion along the pressure relief groove 2111 when the cylindrical battery cell 20 is depressurized, so as to release the internal pressure of the second cavity 2142. The maximum dimension of the second cavity 2142 along the thickness direction X of the first wall is H1, and the maximum dimension of the outer casing 21 is H2, satisfying 0.003≤H1 / H2≤0.06.

[0293] The cavity 214 inside the outer shell 21 serves to accommodate the electrode assembly 22 and the first current collector 23. The body portion 231 is configured to divide the cavity 214 into a first cavity 2141 and a second cavity 2142 that are interconnected. The electrode assembly 22 is accommodated in the first cavity 2141. The second cavity 2142 is located between the body portion 231 and the first wall 211 in the thickness direction X of the first wall. That is, the body portion 231 of the first current collector 23 is disposed between the electrode assembly 22 and the protrusion 2121 in the thickness direction X of the first wall, so that the space on the side of the body portion 231 facing the electrode assembly 22 is the first cavity 2141, and the space between the body portion 231 and the first wall 211 is the second cavity 2142, so that the first cavity 2141 and the second cavity 2142 are arranged along the thickness direction X of the first wall and are located on both sides of the body portion 231.

[0294] The pressure relief component is configured to split at least a portion along the pressure relief groove 2111 when the cylindrical battery cell 20 is depressurized, so as to release the internal pressure of the second cavity 2142. That is, when the cylindrical battery cell 20 is depressurized, after at least a portion of the area of ​​the pressure relief component on the first wall 211 where the pressure relief groove 2111 is provided splits, the second cavity 2142 can be directly connected to the outside of the outer casing 21, so that the thermal runaway gas in the second cavity 2142 can be directly discharged.

[0295] It should be noted that in the embodiment where the pressure relief component and the first wall 211 are integrally formed, the first wall 211 is configured to crack at least a portion along the pressure relief groove 2111 when the cylindrical battery cell 20 is depressurized, so as to release the internal pressure of the second cavity 2142. That is, when the cylindrical battery cell 20 is depressurized, after at least a portion of the area of ​​the first wall 211 where the pressure relief groove 2111 is provided cracks, the second cavity 2142 can be directly connected to the outside of the outer shell 21, so that the thermal runaway gas in the second cavity 2142 can be directly discharged.

[0296] For example, the first cavity 2141 and the second cavity 2142 are interconnected, and the area of ​​the pressure relief component on the first wall 211 with the pressure relief groove 2111 is provided in the thickness direction X of the first wall corresponding to the second cavity 2142.

[0297] Along the thickness direction X of the first wall, the maximum dimension of the second cavity 2142 is H1, that is, H1 is the maximum height dimension of the second cavity 2142 in the thickness direction X of the first wall.

[0298] Along the thickness direction X of the first wall, the maximum dimension of the outer shell 21 is H2, that is, H2 is the maximum height dimension of the outer shell 21 in the thickness direction X of the first wall.

[0299] For example, along the thickness direction X of the first wall, the ratio of the maximum dimension H1 of the second cavity 2142 to the maximum dimension H2 of the outer shell 21 can be 0.003, 0.004, 0.005, 0.006, 0.007, 0.008, 0.009, 0.01, 0.012, 0.015, 0.02, 0.025, 0.03, 0.035, 0.04, 0.045, 0.05, 0.055, 0.056, 0.057, 0.058, 0.059, or 0.06, etc.

[0300] Optionally, the maximum height dimension H2 of the housing 21 in the thickness direction X of the first wall is 70mm to 140mm. For example, the maximum height dimension H2 of the housing 21 in the thickness direction X of the first wall can be 70mm, 75mm, 80mm, 85mm, 90mm, 95mm, 100mm, 105mm, 110mm, 115mm, 120mm, 125mm, 130mm, 135mm or 140mm, etc.

[0301] In this embodiment, the main body 231 divides the receiving cavity 214 inside the outer casing 21 into a first cavity and a second cavity arranged along the thickness direction X of the first wall. The electrode assembly 22 is disposed in the first cavity, and the second cavity is located between the first wall 211 and the main body 231. By configuring the pressure relief component to be able to at least partially crack along the pressure relief groove 2111 and release the internal pressure of the second cavity 2142 when the cylindrical battery cell 20 is depressurized, the area of ​​the pressure relief component with the pressure relief groove 2111 on the first wall 211 is a structure corresponding to the second cavity 2142. With this structure, the cylindrical battery cell 20 can achieve separation between the electrode assembly 22 and the pressure relief component through the second cavity 2142, thereby alleviating the obstruction and shielding of the pressure relief component by the electrode assembly 22 when the cylindrical battery cell 20 is depressurized. This allows the interior of the outer casing 21 to have a second cavity 2142 for buffering and releasing thermal runaway gas, which is beneficial to improving the internal exhaust smoothness of the cylindrical battery cell 20. The second cavity 2142 is located along the thickness direction X of the first wall. The maximum dimension of the second cavity 2142 is 0.003 to 0.06 times the maximum dimension of the outer shell 21 in the thickness direction X of the first wall. On the one hand, by setting the maximum dimension of the second cavity 2142 in the thickness direction X of the first wall to be greater than or equal to 0.003 times the maximum dimension of the outer shell 21 in the thickness direction X of the first wall, there is sufficient space between the body 231 and the first wall 211 to buffer and discharge thermal runaway gas. This is beneficial to improve the internal exhaust smoothness and depressurization rate of the cylindrical battery cell 20, thereby reducing the risk of the cylindrical battery cell 20 bursting or exploding due to untimely depressurization. On the other hand, by setting the maximum dimension of the second cavity 2142 in the thickness direction X of the first wall to be less than or equal to 0.06 times the maximum dimension of the outer shell 21 in the thickness direction X of the first wall, the phenomenon that the second cavity 2142 occupies too much space in the receiving cavity 214 for setting the electrode assembly 22 can be alleviated, thereby improving the internal space utilization of the cylindrical battery cell 20 and improving the energy density of the cylindrical battery cell 20.

[0302] In some embodiments, please continue to refer to Figures 5 and 6, 0.01≤H1 / H2≤0.03.

[0303] In this embodiment, on the one hand, the maximum size of the second cavity 2142 in the thickness direction X of the first wall is further set to be greater than or equal to 0.01 times the maximum size of the outer shell 21 in the thickness direction X of the first wall, so that there is more space between the body 231 and the first wall 211 to buffer and discharge thermal runaway gas, which is beneficial to further improve the internal exhaust smoothness and depressurization rate of the cylindrical battery cell 20, thereby further reducing the risk of the cylindrical battery cell 20 bursting or exploding due to untimely depressurization. On the other hand, the maximum size of the second cavity 2142 in the thickness direction X of the first wall is further set to be less than or equal to 0.03 times the maximum size of the outer shell 21 in the thickness direction X of the first wall, so as to further alleviate the phenomenon that the second cavity 2142 occupies too much space in the accommodating cavity 214 for setting the electrode assembly 22, thereby further improving the internal space utilization of the cylindrical battery cell 20, and further improving the energy density of the cylindrical battery cell 20.

[0304] According to some embodiments of this application, as shown in Figure 6, 0.4mm≤H1≤4mm.

[0305] For example, the maximum dimension H1 of the second cavity 2142 in the thickness direction X of the first wall can be 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, 1.2mm, 1.5mm, 1.8mm, 2mm, 2.2mm, 2.5mm, 2.8mm, 3mm, 3.2mm, 3.5mm, 3.8mm or 4mm, etc.

[0306] In this embodiment, by setting the maximum dimension of the second cavity 2142 in the thickness direction X of the first wall to 0.4mm to 4mm, on the one hand, more space can be provided between the main body 231 and the first wall 211 to buffer and discharge thermal runaway gas. This reduces the obstruction of the exhaust path inside the cylindrical battery cell 20 by the electrode assembly 22 and the main body 231 when the cylindrical battery cell 20 is depressurized, thereby further improving the smoothness of internal exhaust and the depressurization rate of the cylindrical battery cell 20, reducing the risk of the cylindrical battery cell 20 bursting or exploding due to untimely depressurization. On the other hand, it can alleviate the phenomenon that the second cavity 2142 occupies too much space in the receiving cavity 214 for setting the electrode assembly 22, thereby further improving the internal space utilization of the cylindrical battery cell 20 and further improving the energy density of the cylindrical battery cell 20.

[0307] According to some embodiments of this application, as shown in Figure 6, the capacity of the cylindrical battery cell 20 is C, which satisfies 0.005mm / Ah ≤ H1 / C ≤ 0.2mm / Ah.

[0308] For example, the ratio of the maximum dimension H1 of the second cavity 2142 in the thickness direction X of the first wall to the capacitance C of the cylindrical battery cell 20 can be 0.005 mm / Ah, 0.006 mm / Ah, 0.007 mm / Ah, 0.008 mm / Ah, 0.009 mm / Ah, 0.01 mm / Ah, 0.02 mm / Ah, 0.03 mm / Ah, 0.04 mm / Ah, or 0.05 mm / Ah. / Ah, 0.06mm / Ah, 0.07mm / Ah, 0.08mm / Ah, 0.09mm / Ah, 0.1mm / Ah, 0.11mm / Ah, 0.12mm / Ah, 0.13mm / Ah, 0.14mm / Ah, 0.15mm / Ah, 0.16mm / Ah, 0.17mm / Ah, 0.18mm / Ah, 0.19mm / Ah, or 0.2mm / Ah, etc.

[0309] In this embodiment, on the one hand, by setting the ratio of the maximum dimension of the second cavity 2142 in the thickness direction X of the first wall to the capacitance of the cylindrical battery cell 20 to be greater than or equal to 0.005 mm / Ah, the second cavity 2142 has sufficient space to buffer and discharge thermal runaway gas when the cylindrical battery cell 20 is depressurized. This helps to match the space for venting inside the casing 21 with the gas generation rate of the cylindrical battery cell 20 during thermal runaway, thereby improving the smoothness of internal venting of the cylindrical battery cell 20. This effectively reduces the risk of the cylindrical battery cell 20 bursting or exploding due to untimely depressurization. On the other hand, by setting the ratio of the maximum dimension of the second cavity 2142 in the thickness direction X of the first wall to the capacitance of the cylindrical battery cell 20 to be less than or equal to 0.2 mm / Ah, the excessive waste of space for venting inside the casing 21 is alleviated, thereby improving the utilization rate of the internal space of the cylindrical battery cell 20 and increasing the energy density of the cylindrical battery cell 20.

[0310] In some embodiments, please continue to refer to Figure 6, the positive electrode material of the cylindrical battery cell 20 includes lithium transition metal oxide, and H1 and C further satisfy 0.01mm / Ah≤H1 / C≤0.2mm / Ah.

[0311] The positive electrode material of the cylindrical battery cell 20 includes lithium transition metal oxide, that is, the positive electrode material of the electrode assembly 22 of the cylindrical battery cell 20 includes at least one of lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide and their modified compounds.

[0312] In this embodiment, when the positive electrode material of the cylindrical battery cell 20 includes lithium transition metal oxide, by further adjusting the ratio of the maximum dimension of the second cavity 2142 in the thickness direction X of the first wall to the capacitance of the cylindrical battery cell 20 from 0.01 mm / Ah to 0.2 mm / Ah, the space for venting inside the casing 21 can be further matched with the gas generation rate of the cylindrical battery cell 20 during thermal runaway. On the one hand, this can further improve the smoothness of internal venting of the cylindrical battery cell 20, thereby further reducing the risk of the cylindrical battery cell 20 bursting or exploding due to untimely pressure relief. On the other hand, it can further alleviate the phenomenon of excessive waste of space for venting inside the casing 21, thereby further improving the internal space utilization rate of the cylindrical battery cell 20, which is conducive to further improving the energy density of the cylindrical battery cell 20.

[0313] In some embodiments, please continue to refer to Figure 6, the positive electrode material of the cylindrical battery cell 20 includes lithium phosphate, and H1 and C further satisfy 0.005mm / Ah≤H1 / C≤0.1mm / Ah.

[0314] The positive electrode material of the cylindrical battery cell 20 includes lithium phosphate, that is, the positive electrode material of the electrode assembly 22 of the cylindrical battery cell 20 includes at least one of lithium iron phosphate, a composite material of lithium iron phosphate and carbon, lithium manganese phosphate, a composite material of lithium manganese phosphate and carbon, lithium manganese iron phosphate, and a composite material of lithium manganese iron phosphate and carbon.

[0315] In this embodiment, when the positive electrode material of the cylindrical battery cell 20 includes lithium phosphate, by further adjusting the ratio of the maximum dimension of the second cavity 2142 in the thickness direction X of the first wall to the capacitance of the cylindrical battery cell 20 from 0.005 mm / Ah to 0.1 mm / Ah, the space for venting inside the casing 21 can be further matched with the gas generation rate of the cylindrical battery cell 20 during thermal runaway. On the one hand, this can further improve the smoothness of internal venting of the cylindrical battery cell 20, thereby further reducing the risk of the cylindrical battery cell 20 bursting or exploding due to untimely pressure relief. On the other hand, it can further alleviate the phenomenon of excessive waste of space for venting inside the casing 21, thereby further improving the internal space utilization rate of the cylindrical battery cell 20, which is conducive to further improving the energy density of the cylindrical battery cell 20.

[0316] According to some embodiments of this application, as shown in Figures 5, 6 and 7, the outer diameter of the electrode assembly 22 along the radial direction of the cylindrical battery cell 20 is D7, which satisfies 0.7≤D1 / D7≤0.95.

[0317] Wherein, along the radial direction of the cylindrical battery cell 20, the outer diameter of the electrode assembly 22 is D7, that is, D7 is the diameter of the circle containing the outer contour of the main body 221 of the electrode assembly 22 in the projection plane perpendicular to the thickness direction X of the first wall.

[0318] For example, along the radial direction of the cylindrical battery cell 20, the ratio of the inner diameter D1 of the protrusion 2121 to the outer diameter D7 of the electrode assembly 22 can be 0.7, 0.71, 0.72, 0.73, 0.74, 0.75, 0.76, 0.78, 0.8, 0.82, 0.84, 0.85, 0.86, 0.88, 0.9, 0.91, 0.92, 0.93, 0.94, or 0.95, etc.

[0319] In this embodiment, by setting the ratio of the inner diameter of the protrusion 2121 to the outer diameter of the electrode assembly 22 to 0.7 to 0.95, the inner diameter of the protrusion 2121 is set to be greater than or equal to 0.7 times the outer diameter of the electrode assembly 22. This results in a large portion of the electrode assembly 22 being a structure located on the inner side of the protrusion 2121 along the thickness direction X of the first wall. This reduces the obstruction of the protrusion 2121 to the exhaust path inside the cylindrical battery cell 20, which is beneficial for improving the smoothness of internal exhaust and the pressure relief rate of the cylindrical battery cell 20, thereby effectively... To reduce the risk of the cylindrical battery cell 20 bursting or exploding due to untimely pressure release, the inner diameter of the protrusion 2121 is set to be less than or equal to 0.95 times the outer diameter of the electrode assembly 22, so that the electrode assembly 22 and the protrusion 2121 overlap in the projection of the first wall in the thickness direction X. This improves the support effect of the protrusion 2121 on the electrode assembly 22 through the body portion 231, and also improves the effect of the body portion 231 of the first current collector 23 against the expansion of the electrode assembly 22 during the use of the cylindrical battery cell 20.

[0320] In some embodiments, please continue to refer to Figures 5, 6 and 7, 0.75≤D1 / D7≤0.9.

[0321] In this embodiment, on the one hand, the inner diameter of the protrusion 2121 is further set to be greater than or equal to 0.75 times the outer diameter of the electrode assembly 22, so as to further increase the area of ​​the region of the electrode assembly 22 corresponding to the inner side of the protrusion 2121 in the thickness direction X of the first wall. This can further reduce the obstruction of the exhaust path inside the cylindrical battery cell 20 by the protrusion 2121, which is conducive to further improving the smoothness of internal exhaust and pressure relief rate of the cylindrical battery cell 20. In this way, the risk of the cylindrical battery cell 20 bursting or exploding due to untimely pressure relief can be further reduced. On the other hand, the inner diameter of the protrusion 2121 is further set to be less than or equal to 0.9 times the outer diameter of the electrode assembly 22, so as to further increase the area of ​​the overlapping region of the electrode assembly 22 and the protrusion 2121 in the thickness direction X of the first wall. This can further improve the support effect of the protrusion 2121 on the electrode assembly 22 through the body part 231, and can also further improve the effect of the body part 231 of the first current collector 23 against the expansion of the electrode assembly 22 during the use of the cylindrical battery cell 20.

[0322] According to some embodiments of this application, referring to FIG6, the projection of the pressure relief groove 2111 along the thickness direction X of the first wall is located within the second cavity 2142. That is, along the thickness direction X of the first wall, the area on the first wall 211 where the pressure relief component is provided with the pressure relief groove 2111 corresponds to the structure provided in the second cavity 2142.

[0323] In this embodiment, by setting the pressure relief groove 2111 to a structure in which the projection of the first wall in the thickness direction X is located within the second cavity 2142, the area where the pressure relief component on the first wall 211 is provided with the pressure relief groove 2111 is a structure in the thickness direction X of the first wall corresponding to the second cavity 2142. This makes it easier for the thermal runaway gas in the second cavity 2142 to be discharged when the cylindrical battery cell 20 experiences thermal runaway and the pressure relief component cracks at least partially along the pressure relief groove 2111 to release pressure. This is beneficial to further improve the emission rate of the thermal runaway gas in the second cavity 2142, thereby further improving the pressure relief rate of the cylindrical battery cell 20 and further reducing the risk of the cylindrical battery cell 20 bursting or exploding due to untimely pressure relief.

[0324] According to some embodiments of this application, referring to Figures 6, 8, and 9, the mating portion 232 may include a connecting region 2321 and an elastic region 2322. The connecting region 2321 is disposed on the side of the main body region 2311 facing the first wall 211 in the thickness direction X of the first wall, and is connected to the protrusion 2121. The elastic region 2322 connects the connecting region 2321 and the main body region 2311, and is configured to deform when the main body region 2311 and the connecting region 2321 move closer or further apart along the thickness direction X of the first wall.

[0325] The body portion 231 of the first current collector 23 is disposed at one end of the electrode assembly 22 in the thickness direction X of the first wall near the protrusion 2121, and the body portion 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.

[0326] The connecting area 2321 is disposed on the side of the main body area 2311 facing the first wall 211 in the thickness direction X of the first wall, and the connecting area 2321 and the main body area 2311 are spaced apart. That is, the main body area 2311 and the connecting area 2321 are arranged in a structure that is spaced apart along the thickness direction X of the first wall, and the connecting area 2321 is closer to the first wall 211 in the thickness direction X of the first wall than the main body area 2311.

[0327] The elastic region 2322 is a structure connecting the main body region 2311 and the connecting region 2321. The elastic region 2322 is configured to deform when the main body region 2311 and the connecting region 2321 move closer or further away from each other along the thickness direction X of the first wall. That is, when the first current collector 23 is compressed or stretched in the thickness direction X of the first wall, the elastic region 2322 can deform when the main body region 2311 and the connecting region 2321 move closer or further away from each other. It should be noted that the elastic region 2322 can undergo elastic deformation or plastic deformation when it deforms.

[0328] Optionally, in Figures 8 and 9, each connection area 2321 is connected to the main body area 2311 through an elastic area 2322, and each connection area 2321 is welded to the protrusion 2121. For example, the connection area 2321 is an arc-shaped structure extending circumferentially along the sidewall 212.

[0329] Optionally, the body portion 231 and the docking portion 232 of the first current collector 23 can be an integrally formed structure or a separate but connected structure. For example, in FIG8, the body portion 231 and the docking portion 232 of the first current collector 23 are an integral structure formed by an integral forming process such as stamping and cutting.

[0330] Similarly, the main body area 2311 and the support area 2312 of the body part 231 can be an integrally formed structure or a separate but connected structure. For example, in Figures 8 and 9, the main body area 2311 and the support area 2312 of the body part 231 are integrally formed structures through integral forming processes such as stamping and cutting.

[0331] Similarly, the connection area 2321 and the elastic area 2322 of the docking part 232 can be an integrally formed structure or a separate but connected structure. For example, in Figures 8 and 9, the connection area 2321 and the elastic area 2322 of the docking part 232 are integrally formed structures through integral forming processes such as stamping and cutting.

[0332] In this embodiment, the docking portion 232 is provided with a connecting area 2321 and an elastic area 2322. The connecting area 2321 is connected to the protrusion 2121, and the elastic area 2322 is connected between the main body portion 2311 and the connecting area 2321 to realize the electrical connection between the protrusion 2121 and the main body portion 231. Specifically, the connecting area 2321 is positioned on the side of the main body portion 2311 facing the first wall 211 in the thickness direction X of the first wall, and the elastic area 2322 is configured to allow the main body portion 2311 and the connecting area 2321 to move closer or further apart along the thickness direction X of the first wall. The deformable structure allows the elastic zone 2322 to act as a buffer between the main body zone 2311 and the connecting zone 2321. This helps to alleviate the rigid tension between the main body zone 2311 and the connecting zone 2321, between the main body zone 2311 and the electrode assembly 22, and between the connecting zone 2321 and the protrusion 2121 during the shaking or displacement of the electrode assembly 22. This helps to further reduce the risk of connection failure between the main body zone 2311 and the electrode assembly 22, and between the connecting zone 2321 and the protrusion 2121, and also helps to reduce the phenomenon of the first current collector 23 being damaged by tension.

[0333] In some embodiments, as shown in FIG8, the elastic region 2322 is bent to form a plurality of bent segments 2322a, the plurality of bent segments 2322a are connected in sequence, and the bent segments 2322a located at both ends of the plurality of bent segments 2322a are respectively connected to the main body region 2311 and the connecting region 2321.

[0334] The elastic region 2322 is bent to form multiple bending segments 2322a, which are connected in sequence. In other words, the elastic region 2322 is a structure with local bending, so that the elastic region 2322 forms multiple bending segments 2322a connected in sequence, and each pair of adjacent bending segments 2322a is set at an acute angle, a right angle or an obtuse angle.

[0335] For example, in FIG8, the elastic region 2322 is bent to form three bent segments 2322a connected in sequence, and the two bent segments 2322a at both ends of the three bent segments 2322a are respectively connected to the main body region 2311 and the connecting region 2321. Of course, in other embodiments, the number of bent segments 2322a formed by bending the elastic region 2322 can also be two, four, five or six, etc.

[0336] In this embodiment, by setting the elastic region 2322 as a structure of bending to form a plurality of sequentially connected bent segments 2322a, and the bent segments 2322a at both ends of the plurality of bent segments 2322a being connected to the main body region 2311 and the connecting region 2321 respectively, the deformation capacity of the elastic region 2322 when the main body region 2311 and the connecting region 2321 approach or move away from each other along the thickness direction X of the first wall can be increased, so as to further improve the buffering effect of the elastic region 2322 between the main body region 2311 and the connecting region 2321, and further reduce the phenomenon of rigid pulling between the main body region 2311 and the connecting region 2321, between the main body region 2311 and the electrode assembly 22, and between the connecting region 2321 and the protrusion 2121.

[0337] According to some embodiments of this application, referring to Figures 8 and 9, in a projection plane perpendicular to the thickness direction X of the first wall, the orthographic projection of the connecting region 2321 extends circumferentially along the sidewall 212 and is located on the periphery of the orthographic projection of the main body region 2311. The orthographic projection of the connecting region 2321 and the orthographic projection of the main body region 2311 are arranged radially spaced apart in the cylindrical battery cell 20, so as to form an exhaust gap 234 between the orthographic projection of the connecting region 2321 and the orthographic projection of the main body region 2311.

[0338] In this embodiment, in the projection plane perpendicular to the thickness direction X of the first wall, the orthographic projection of the connecting area 2321 and the orthographic projection of the main body area 2311 are set to form an exhaust gap 234 in the radial direction of the cylindrical battery cell 20. This allows the thermal runaway gas inside the cylindrical battery cell 20 to enter the side of the first current collector 23 facing the first wall 211 through the exhaust gap 234 between the connecting area 2321 and the main body area 2311 and then be released. 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 depressurization rate of the cylindrical battery cell 20.

[0339] In some embodiments, as shown in Figures 6 and 9, at least a portion of the projection of the pressure relief groove 2111 is located within the exhaust gap 234 along the thickness direction X of the first wall. That is, at least a portion of the area on the first wall 211 where the pressure relief component is provided with the pressure relief groove 2111 is a structure provided in the thickness direction X of the first wall corresponding to the exhaust gap 234 between the main body region 2311 and the connecting region 2321.

[0340] In this embodiment, by setting the pressure relief groove 2111 to a structure in which at least a portion of its projection in the thickness direction X of the first wall is located within the exhaust gap 234, the pressure relief groove 2111 is a structure in which at least a portion in the thickness direction X of the first wall corresponds to the exhaust gap 234 between the connecting area 2321 and the main body area 2311. This can further improve 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 can reduce the risk of fire and explosion caused by untimely pressure relief of the cylindrical battery cell 20, thereby improving the reliability of the cylindrical battery cell 20.

[0341] According to some embodiments of this application, referring to Figures 8 and 9, in the projection plane perpendicular to the thickness direction X of the first wall, the diameter of the orthographic projection of the outer edge of the connecting area 2321 is D8, and the orthographic projection of the elastic area 2322 extends radially along the cylindrical battery cell 20 with a length of L6, satisfying 1 / 15≤L6 / D8≤1 / 3.

[0342] In the projection plane perpendicular to the thickness direction X of the first wall, the orthographic projection of the connecting area 2321 extends circumferentially along the side wall 212 and is located around the orthographic projection of the main body area 2311. That is, the orthographic projection of the connecting area 2321 in the thickness direction X of the first wall is an arc-shaped or ring-shaped structure extending circumferentially along the side wall 212, and the connecting area 2321 is arranged around the main body area 2311. For example, in Figure 9, the first collecting member 23 is provided with multiple connecting portions 232, and the connecting areas 2321 of the multiple connecting portions 232 are arranged at intervals circumferentially along the side wall 212 and are arranged around the main body area 2311. Each connecting area 2321 is an arc-shaped structure extending circumferentially along the side wall 212. Correspondingly, in the projection plane perpendicular to the thickness direction X of the first wall, the diameter D8 of the orthographic projection of the outer edge of the connecting area 2321 is the diameter of the circle containing the orthographic projection of the outer edge of the connecting area 2321.

[0343] In the projection plane perpendicular to the thickness direction X of the first wall, the orthographic projection of the connecting area 2321 and the orthographic projection of the main body area 2311 are arranged radially on the cylindrical battery cell 20, and the orthographic projection of the elastic area 2322 extends radially along the cylindrical battery cell 20. That is, the orthographic projection of the connecting area 2321 and the orthographic projection of the main body area 2311 in the thickness direction X of the first wall are arranged radially on the cylindrical battery cell 20, and the elastic area 2322 connects the connecting area 2321 and the main body area 2311 radially along the cylindrical battery cell 20.

[0344] Optionally, in the projection plane perpendicular to the thickness direction X of the first wall, the ratio of the length L6 of the orthographic projection of the elastic region 2322 onto the radial direction of the cylindrical battery cell 20 to the diameter D8 of the orthographic projection of the outer edge of the connecting region 2321 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.

[0345] In this embodiment, in the projection plane perpendicular to the thickness direction X of the first wall, the orthographic projections of the connecting area 2321 and the main body area 2311 are arranged at intervals in the radial direction of the cylindrical battery cell 20. Furthermore, the ratio of the length of the elastic region 2322 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 connecting area 2321 is set to 1 / 15 to 1 / 3. This alleviates the problem of the elastic region 2322 occupying too small a size in the radial direction of the cylindrical battery cell 20, and helps to expand the exhaust space between the connecting area 2321 and the main body area 2311. This allows the thermal runaway gas inside the cylindrical battery cell 20 to pass through the exhaust space between the connecting area 2321 and the main body area 2311 and then through the first wall 211. The pressure relief component is provided with a pressure relief groove 2111 in the area for pressure relief, which can improve the smoothness of internal venting of the cylindrical battery cell 20, thereby increasing the pressure relief rate of the cylindrical battery cell 20. This can reduce the risk of the cylindrical battery cell 20 bursting or exploding due to untimely pressure relief. On the other hand, it can alleviate the phenomenon that the elastic region 2322 occupies too large a size in the radial direction of the cylindrical battery cell 20, resulting in insufficient support strength of the elastic region 2322 between the main body region 2311 and the connecting region 2321. This can effectively 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 alleviating the phenomenon of excessive expansion or displacement of the electrode assembly 22, which is conducive to improving the stability and reliability of the cylindrical battery cell 20.

[0346] In some embodiments, as shown in Figure 9, 1 / 7 ≤ L6 / D8 ≤ 1 / 4.

[0347] In this embodiment, in the projection plane perpendicular to the thickness direction X of the first wall, by further setting the ratio of the length of the elastic region 2322 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 connecting region 2321 to 1 / 7 to 1 / 4, on the one hand, the phenomenon that the elastic region 2322 occupies too small a size in the radial direction of the cylindrical battery cell 20 can be further alleviated, and it is beneficial to further expand the exhaust space between the connecting region 2321 and the main body region 2311, so that the thermal runaway gas inside the cylindrical battery cell 20 can be released through the exhaust space between the connecting region 2321 and the main body region 2311 and then through the area of ​​the pressure relief component on the first wall 211 with the pressure relief groove 2111, thereby further improving the efficiency of the battery cell. The smooth internal venting of the cylindrical battery cell 20 further improves the pressure relief rate of the cylindrical battery cell 20, thereby reducing the risk of bursting or exploding due to untimely pressure relief. On the other hand, it can further alleviate the phenomenon that the elastic region 2322 occupies too large a size in the radial direction of the cylindrical battery cell 20, resulting in insufficient support strength of the elastic region 2322 between the main body region 2311 and the connecting region 2321. 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, which is conducive to further improving the stability and reliability of the cylindrical battery cell 20 in use.

[0348] In some embodiments, please continue to refer to Figure 9, where 3mm ≤ L6 ≤ 15mm.

[0349] Optionally, in the projection plane perpendicular to the thickness direction X of the first wall, the length L6 of the orthographic projection of the elastic zone 2322 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.

[0350] In this embodiment, in the projection plane perpendicular to the thickness direction X of the first wall, by setting the length of the elastic region 2322 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 elastic region 2322 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 connection region 2321 and the main body region 2311, so that the thermal runaway gas inside the cylindrical battery cell 20 can pass through the exhaust space between the connection region 2321 and the main body region 2311 and then through the pressure relief component on the first wall 211. The pressure relief groove 2111 releases pressure, which helps to improve the smoothness of internal venting of the cylindrical battery cell 20. On the other hand, setting the length of the elastic region 2322 in the radial direction of the cylindrical battery cell 20 to less than or equal to 15mm can alleviate the phenomenon that the elastic region 2322 is too long and therefore the support strength of the elastic region 2322 between the main body region 2311 and the connecting region 2321 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.

[0351] According to some embodiments of this application, and in conjunction with Figures 6 and 9, the thickness of the elastic region 2322 is T2. In the projection plane perpendicular to the thickness direction X of the first wall, the width of the orthographic projection of the elastic region 2322 in the direction perpendicular to its extension direction is W, satisfying 0.3mm. 2 ≤W×T2≤8mm 2 .

[0352] Wherein, the thickness of the elastic region 2322 is T2, which is the thickness at any position of the elastic region 2322. In an embodiment where the elastic region 2322 includes a plurality of sequentially connected bending segments 2322a, the thickness of each bending segment 2322a is T2.

[0353] Alternatively, the product of W and T2 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 25.5mm 2 6mm 2 6.5mm 2 7mm 2 7.5mm 2 Or 8mm 2 wait.

[0354] In this embodiment, the product of W and T2 is set to 0.3mm. 2 up to 8mm 2 On the one hand, the product of W and T2 is set to be less than or equal to 8mm. 2 This design mitigates the problem of excessive deformation difficulty in the elastic region 2322 caused by excessively large W and T2 values. It enhances the elastic region 2322's ability to deform when the main body region 2311 and the connecting region 2321 move closer or further apart along the thickness direction X of the first wall. This allows the elastic region 2322 to provide better buffering between the main body region 2311 and the connecting region 2321, thereby reducing rigid tension between the main body region 2311 and the connecting region 2321, between the main body region 2311 and the electrode assembly 22, and between the connecting region 2321 and the protrusion 2121 during periods of shaking or displacement of the electrode assembly 22. Furthermore, setting the product of W and T2 to be greater than or equal to 0.3 mm... 2 It can improve the structural strength of the elastic region 2322, which helps to alleviate the phenomenon of insufficient support strength of the elastic region 2322 between the main body region 2311 and the connecting region 2321, 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 elastic region 2322, which is conducive to improving the flow guiding effect and flow guiding requirements of the first current collector 23.

[0355] In some embodiments, as shown in Figures 8 and 9, 2mm ≤ W ≤ 10mm.

[0356] Optionally, the width W of the projection of the elastic region 2322 onto the thickness direction X of the first wall 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.

[0357] In this embodiment, by setting the width of the projection of the elastic region 2322 of the first current collector 23 onto the thickness direction X of the first wall to 2mm to 10mm, on the one hand, setting the width of the projection of the elastic region 2322 onto the thickness direction X of the first wall to be greater than or equal to 2mm can improve the flow capacity of the elastic region 2322, 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 elastic region 2322, which helps to alleviate the phenomenon of insufficient support strength of the elastic region 2322 between the main body region 2311 and the connecting region 2321, thereby improving the support effect of the first current collector 23 on the electrode assembly 22 and the resistance of the electrode assembly 22 during use. On the other hand, setting the width of the projection of the elastic region 2322 on the thickness direction X of the first wall to be less than or equal to 10 mm can effectively improve the ability of the elastic region 2322 to deform when the main body region 2311 and the connecting region 2321 move closer or further apart along the thickness direction X of the first wall. This allows the elastic region 2322 to play a better buffering role between the main body region 2311 and the connecting region 2321, thereby reducing the rigid pulling phenomenon between the main body region 2311 and the connecting region 2321, between the main body region 2311 and the electrode assembly 22, and between the connecting region 2321 and the protrusion 2121 during the shaking or displacement of the electrode assembly 22.

[0358] In some embodiments, as shown in Figure 9, 3mm ≤ W ≤ 5mm.

[0359] In this embodiment, by further setting the width of the projection of the elastic region 2322 of the first current collector 23 onto the thickness direction X of the first wall to 3mm to 5mm, on the one hand, setting the width of the projection of the elastic region 2322 onto the thickness direction X of the first wall to be greater than or equal to 3mm can further improve the flow capacity of the elastic region 2322, 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 elastic region 2322, which is beneficial to further alleviate the phenomenon of insufficient support strength of the elastic region 2322 between the main body region 2311 and the connecting region 2321, thereby further improving the support effect of the first current collector 23 on the electrode assembly 22 and the resistance to the electrode. The expansion effect of component 22 during use, on the other hand, setting the width of the projection of elastic region 2322 on the thickness direction X of the first wall to be less than or equal to 5mm can further enhance the ability of elastic region 2322 to deform when the main body region 2311 and connecting region 2321 move closer or further apart along the thickness direction X of the first wall, so as to enhance the buffering effect of elastic region 2322 between main body region 2311 and connecting region 2321, thereby further reducing the rigid pulling phenomenon between main body region 2311 and connecting region 2321, between main body region 2311 and electrode component 22, and between connecting region 2321 and protrusion 2121 during the process of electrode component 22 shaking or displacement.

[0360] According to some embodiments of this application, as shown in Figures 6 and 8, the thickness of the elastic region 2322 is T2, which satisfies 0.15mm≤T2≤0.8mm.

[0361] Optionally, the thickness T2 of the elastic region 2322 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.

[0362] In this embodiment, by setting the thickness of the elastic region 2322 of the docking portion 232 to 0.15mm to 0.8mm, on the one hand, setting the thickness of the elastic region 2322 to be greater than or equal to 0.15mm can improve the flow capacity of the elastic region 2322, thereby improving the flow guiding effect of the first current collecting member 23, and can also improve the structural strength of the elastic region 2322. This helps to alleviate the phenomenon of insufficient support strength of the elastic region 2322 between the main body region 2311 and the connecting region 2321, thereby improving the support effect of the first current collecting member 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 elastic region 2322 to be less than or equal to 0.8mm can improve the flow capacity of the elastic region 2322, thereby improving the flow guiding effect of the first current collecting member 23 on the electrode assembly 22 and the effect of resisting the expansion of the electrode assembly 22 during use. The 0.8mm thickness effectively enhances the ability of the elastic region 2322 to deform when the main body region 2311 and the connecting region 2321 move closer or further apart along the thickness direction X of the first wall. This allows the elastic region 2322 to play a better buffering role between the main body region 2311 and the connecting region 2321, thereby reducing rigid tension between the main body region 2311 and the connecting region 2321, between the main body region 2311 and the electrode assembly 22, and between the connecting region 2321 and the protrusion 2121 during the shaking or displacement of the electrode assembly 22. It also saves the space occupied by the elastic region 2322 in the thickness direction X of the first wall, which is beneficial to improving the internal space utilization of the cylindrical battery cell 20.

[0363] In some embodiments, please continue to refer to Figures 6 and 8, 0.3mm≤T2≤0.5mm.

[0364] In this embodiment, by further setting the thickness of the elastic region 2322 of the docking portion 232 to 0.3mm to 0.5mm, on the one hand, setting the thickness of the elastic region 2322 to be greater than or equal to 0.3mm can further improve the flow capacity of the elastic region 2322, thereby further improving the flow guiding effect of the first current collecting member 23, and can further improve the structural strength of the elastic region 2322. This helps to further alleviate the phenomenon of insufficient support strength of the elastic region 2322 between the main body region 2311 and the connecting region 2321, thereby further improving the support effect of the first current collecting member 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 elastic region 2322 to be less than 0.3mm can further improve the flow capacity of the elastic region 2322, thereby improving the flow guiding effect of the first current collecting member 23 on the electrode assembly 22 and the effect of resisting the expansion of the electrode assembly 22 during use. A thickness of 0.5 mm or more can further enhance the ability of the elastic region 2322 to deform when the main body region 2311 and the connecting region 2321 move closer or further apart along the thickness direction X of the first wall. This can further enhance the buffering effect of the elastic region 2322 between the main body region 2311 and the connecting region 2321. As a result, during the process of the electrode assembly 22 shaking or shifting, it can further reduce the rigid pulling phenomenon between the main body region 2311 and the connecting region 2321, between the main body region 2311 and the electrode assembly 22, and between the connecting region 2321 and the protrusion 2121. It can also further save the space occupied by the elastic region 2322 in the thickness direction X of the first wall, which is conducive to further improving the internal space utilization of the cylindrical battery cell 20.

[0365] According to some embodiments of this application, as shown in Figures 6 and 8, the thickness of the elastic region 2322 is less than the thickness of the main body region 2311.

[0366] In this embodiment, by setting the thickness of the elastic region 2322 to be less than the thickness of the main body region 2311, the manufacturing cost and manufacturing difficulty of the first current collector 23 are reduced, while the ability of the elastic region 2322 to deform when the main body region 2311 and the connecting region 2321 move closer or further apart along the thickness direction X of the first wall is improved, so that the elastic region 2322 can play a better buffering role between the main body region 2311 and the connecting region 2321.

[0367] According to some embodiments of this application, please continue to refer to Figures 6 and 8, the thickness of the elastic region 2322 is less than the thickness of the connecting region 2321.

[0368] In this embodiment, by setting the thickness of the elastic region 2322 to be less than the thickness of the connecting region 2321, the manufacturing cost and manufacturing difficulty of the first current collection component 23 are reduced, while the ability of the elastic region 2322 to deform when the main body region 2311 and the connecting region 2321 move closer or further apart along the thickness direction X of the first wall is improved, so that the elastic region 2322 can play a better buffering role between the main body region 2311 and the connecting region 2321.

[0369] According to some embodiments of this application, referring to Figures 5 and 6, along the thickness direction X of the first wall, the connection area 2321 is disposed on the side of the protrusion 2121 away from the electrode assembly 22 and connected to the protrusion 2121.

[0370] In this embodiment, the connecting region 2321 is located on the side of the protrusion 2121 facing the first wall 211 in the thickness direction X of the first wall, such that the connecting region 2321 and the body portion 231 are respectively located on both sides of the protrusion 2121 in the thickness direction X of the first wall, and the elastic region 2322 connects the connecting region 2321 and the main body portion 2311 of the body portion 231, such that the elastic region 2322 is located on the inner peripheral side of the protrusion 2121, and the elastic region 2322 and the protrusion 2121 share a portion of the space in the thickness direction X of the first wall. Of course, in other embodiments, the connecting region 2321 may also be a structure located on the side of the protrusion 2121 facing the electrode assembly 22, and correspondingly, the connecting region 2321 is connected to the side of the protrusion 2121 facing the electrode assembly 22.

[0371] In this embodiment, by setting the connection area 2321 of the docking portion 232 of the first current collector 23 to be located on the side of the protrusion 2121 away from the electrode assembly 22 in the thickness direction X of the first wall, the connection area 2321 and the body portion 231 are respectively located on both sides of the protrusion 2121 in the thickness direction X of the first wall, and the connection area 2321 and the side of the protrusion 2121 away from the electrode assembly 22 are connected to each other. The cylindrical battery cell 20 with this structure can, on the one hand, realize that the first current collector 23 and the protrusion 2121 can share part of the space in the thickness direction X of the first wall, which is beneficial to improve the internal space utilization of the cylindrical battery cell 20 and thus improve the energy density of the cylindrical battery cell 20. On the other hand, it can realize that the assembly connection between the connection area 2321 and the protrusion 2121 is not affected by the interference of the electrode assembly 22, which is beneficial to reduce the assembly difficulty of the connection area 2321 and the protrusion 2121 of the docking portion 232, and can also help optimize the production process of the cylindrical battery cell 20.

[0372] According to some embodiments of this application, as shown in Figures 4, 5 and 6, along the radial direction of the cylindrical battery cell 20, a groove 2123 is formed on the sidewall 212 facing away from the electrode assembly 22 and corresponding to the position of the protrusion 2121.

[0373] For example, the protrusion 2121 formed on the side of the sidewall 212 facing the electrode assembly 22 is a structure formed by a stamping process, so that the protrusion 2121 is formed on the surface of the sidewall 212 facing the electrode assembly 22, and a groove 2123 is formed on the surface of the sidewall 212 away from the electrode assembly 22 at the position corresponding to the protrusion 2121. Of course, the forming method of the protrusion 2121 formed on the sidewall 212 facing the electrode assembly 22 is not limited to this. In other embodiments, the protrusion 2121 formed on the sidewall 212 facing the electrode assembly 22 can also be formed by a machining process such as casting or milling.

[0374] It should be noted that in the embodiment where the protrusion 2121 is an annular structure extending circumferentially along the sidewall 212, the groove 2123 is also an annular groove structure extending circumferentially along the sidewall 212.

[0375] In this embodiment, by forming a groove 2123 on the side of the sidewall 212 facing away from the electrode assembly 22 and at the position corresponding to the protrusion 2121, the protrusion 2121 formed on the side of the sidewall 212 facing the electrode assembly 22 can be formed by stamping. This allows the cylindrical battery cell 20 to form the protrusion 2121 on the sidewall 212 facing the electrode assembly 22 and the groove 2123 on the other side at the position corresponding to the protrusion 2121. This structure reduces the difficulty of forming the protrusion 2121 on the sidewall 212 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 protrusion 2121 to have a hollow internal structure, which allows the protrusion 2121 to have the ability to deform elastically. This helps to alleviate the rigid tension between the docking part 232 and the protrusion 2121, thereby reducing the risk of connection failure between the docking part 232 and the protrusion 2121.

[0376] According to some embodiments of this application, as shown in Figures 4, 5 and 6, the outer casing 21 further includes a second wall 213, which is disposed opposite to the first wall 211 in the thickness direction X of the first wall. The second wall 213 is integrally formed with the side wall 212. Along the thickness direction X of the first wall, one end of the side wall 212 is connected to the second wall 213, and the other end forms an opening 2122. The side wall 212 and the second wall 213 together define a receiving cavity 214, in which the electrode assembly 22 is received. The first wall 211 closes the opening 2122.

[0377] The second wall 213 is disposed opposite to the first wall 211 in the thickness direction X of the first wall. That is, the first wall 211 and the second wall 213 are the end walls of the outer shell 21 in the thickness direction X of the first wall, respectively, so that the first wall 211 and the second wall 213 are located at the two ends of the side wall 212 in the thickness direction X of the first wall.

[0378] The second wall 213 is integrally formed with the side wall 212, that is, the side wall 212 and the second wall 213 of the outer shell 21 are structures formed by an integral forming process, such as stamping or casting.

[0379] The first wall 211 closes the opening 2122, that is, the first wall 211 is located at the opening 2122 at the end of the side wall 212 away from the second wall 213 in the thickness direction X of the first wall and is sealed to the side wall 212. Optionally, the connection structure between the first wall 211 and the side wall 212 can be various, such as welding connection, snap-fit ​​connection, etc.

[0380] In this embodiment, by setting the sidewall 212 of the outer casing 21 to form an opening 2122 at one end away from the second wall 213 in the thickness direction X of the first wall, and the first wall 211 to close the opening 2122, the first current collector 23 is positioned on the side of the electrode assembly 22 facing the opening 2122 in the thickness direction X of the first wall. This reduces the difficulty of assembling the support area 2312 of the body portion 231 of the first current collector 23 to the electrode assembly 22 and the protrusion 2121, and also reduces the connection difficulty between the docking portion 232 and the protrusion 2121. This reduces the assembly difficulty of the cylindrical battery cell 20 and optimizes the manufacturing process of the cylindrical battery cell 20, which is beneficial to improving the production efficiency of the cylindrical battery cell 20.

[0381] In some embodiments, referring to Figures 6 and 7, the sidewall 212 is bent at one end away from the second wall 213 in the thickness direction X of the first wall to form a flange 2124, which encloses an opening 2122. Along the thickness direction X of the first wall, a portion of the first wall 211 is located between the flange 2124 and the protrusion 2121, and the flange 2124 and the protrusion 2121 are configured to cooperate in clamping the first wall 211.

[0382] The flange 2124 is a flange structure formed by bending one end of the side wall 212 away from the second wall 213 in the thickness direction X of the first wall towards the side closer to the receiving cavity 214. The flange 2124 surrounds and forms an opening 2122, that is, the flange 2124 is an annular structure so as to form an opening 2122 on the inner circumferential side of the flange 2124.

[0383] In this embodiment, the outer edge of the first wall 211 extends between the flange 2124 and the protrusion 2121, so that the flange 2124 and the protrusion 2121 can cooperate to clamp and assemble a portion of the first wall 211, thereby realizing the assembly connection between the first wall 211 and the side wall 212.

[0384] In this embodiment, a flange 2124 is formed by bending the end of the side wall 212 away from the second wall 213 along the thickness direction X of the first wall, and a portion of the first wall 211 is positioned between the protrusion 2121 and the flange 2124 in the thickness direction X of the first wall, so that the protrusion 2121 and the flange 2124 can also play a role in assembling and fixing the first wall 211, so as to realize the assembly between the first wall 211 and the side wall 212. The cylindrical battery cell 20 with this structure can reduce the assembly difficulty between the first wall 211 and the side wall 212, thereby improving the production efficiency of the cylindrical battery cell 20.

[0385] According to some embodiments of this application, referring to Figures 4, 6 and 7, the cylindrical battery cell 20 may further include a seal 29, at least a portion of which is disposed radially between the sidewall 212 and the first wall 211 of the cylindrical battery cell 20, and the seal 29 is configured to seal the gap between the first wall 211 and the sidewall 212.

[0386] At least a portion of the seal 29 is disposed radially between the side wall 212 and the first wall 211 of the cylindrical battery cell 20, that is, at least a portion of the seal 29 is located between the outer peripheral surface of the first wall 211 and the inner peripheral surface of the side wall 212, so that the seal 29 can seal the gap between the outer peripheral surface of the first wall 211 and the inner peripheral surface of the side wall 212.

[0387] Optionally, the seal 29 is made of an insulating material, so that the seal 29 can also serve to insulate and isolate the first wall 211 and the side wall 212. For example, the material of the seal 29 can be rubber, silicone or plastic, etc.

[0388] In this embodiment, the cylindrical battery cell 20 is also provided with a sealing member 29. By disposing at least a portion of the sealing member 29 radially between the side wall 212 and the first wall 211 of the cylindrical battery cell 20, the sealing member 29 can seal the gap between the first wall 211 and the side wall 212, 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.

[0389] In some embodiments, referring to Figures 6 and 7, a portion of the seal 29 is disposed between the first wall 211 and the protrusion 2121 along the thickness direction X of the first wall. That is, a portion of the seal 29 is located between the outer peripheral surface of the first wall 211 and the inner peripheral surface of the side wall 212, and a portion of the seal 29 extends between the first wall 211 and the protrusion 2121, such that a portion of the seal 29 is located between the first wall 211 and the protrusion 2121 in the thickness direction X of the first wall, so that the seal 29 can also separate the first wall 211 and the protrusion 2121.

[0390] It should be noted that in the embodiment where the connecting area 2321 of the docking portion 232 of the first collector 23 is located on the side of the protrusion 2121 facing the first wall 211 and is welded to the protrusion 2121, as shown in FIG6, a portion of the seal 29 is located between the connecting area 2321 and the first wall 211, so that the seal 29 can also separate the connecting area 2321 and the first wall 211.

[0391] In this embodiment, by setting a portion of the seal 29 to extend between the first wall 211 and the protrusion 2121, the seal 29 can also seal the gap between the first wall 211 and the protrusion 2121, which is beneficial to further improve the sealing effect of the seal 29 on the gap between the first wall 211 and the side wall 212. Furthermore, the protrusion 2121 and the first wall 211 can also play a certain clamping role on the seal 29, which is beneficial to improve the assembly stability of the seal 29.

[0392] In some embodiments, referring again to Figures 6 and 7, a portion of the seal 29 is disposed between the first wall 211 and the flange 2124 along the thickness direction X of the first wall. That is, a portion of the seal 29 is located between the outer peripheral surface of the first wall 211 and the inner peripheral surface of the side wall 212, and a portion of the seal 29 extends between the first wall 211 and the flange 2124, such that a portion of the seal 29 is located between the first wall 211 and the flange 2124 in the thickness direction X of the first wall, so that the seal 29 can also separate the first wall 211 and the flange 2124.

[0393] Optionally, in Figure 6, the seal 29 is an annular structure surrounding the first wall 211. The seal 29 may include a first part, a second part, and a third part arranged and connected in sequence along the thickness direction X of the first wall. The first part is located between the protrusion 2121 and the first wall 211 in the thickness direction X of the first wall. The second part is located between the outer peripheral surface of the first wall 211 and the inner peripheral surface of the side wall 212. The third part is located between the flange 2124 and the first wall 211 in the thickness direction X of the first wall.

[0394] In this embodiment, by setting a portion of the seal 29 to extend between the first wall 211 and the flange 2124, the seal 29 can also seal the gap between the first wall 211 and the flange 2124, which helps to further improve the sealing effect of the seal 29 on the gap between the first wall 211 and the side wall 212. Furthermore, the flange 2124 and the first wall 211 can also play a certain clamping role on the seal 29, which helps to improve the assembly stability of the seal 29.

[0395] 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. For example, the sidewall 212 is integrally formed with the first wall 211. Along the thickness direction X of the first wall, one end of the sidewall 212 is connected to the first wall 211, and the other end forms an opening 2122. The sidewall 212 and the first wall 211 together define a receiving cavity 214, in which the electrode assembly 22 is received. The outer shell 21 also includes a second wall 213, which is disposed opposite to the first wall 211 in the thickness direction X of the first wall, and the second wall 213 closes the opening 2122.

[0396] The side wall 212 and the first wall 211 are integrally formed, that is, the side wall 212 and the first wall 211 of the outer shell 21 are structures formed by an integral forming process, such as stamping or casting.

[0397] One end of the side wall 212 is connected to the first wall 211, and the other end is enclosed to form an opening 2122. The second wall 213 closes the opening 2122. That is, the opening 2122 of the side wall 212 is formed in the thickness direction X of the first wall at the end of the side wall 212 away from the first wall 211.

[0398] Optionally, the connection structure between the second wall 213 and the side wall 212 can be various, such as welding connection, snap-fit ​​connection, etc.

[0399] In this embodiment, by setting the first wall 211 and the side wall 212 as an integrally formed structure, and the side wall 212 surrounds the end away from the first wall 211 in the thickness direction X of the first wall to form an opening 2122 for assembling the electrode assembly 22, and the second wall 213 closes the opening 2122, the cylindrical battery cell 20 with this structure can first form a protrusion 2121 on the inner circumferential surface of the side wall 212 before assembling the electrode assembly 22 into the receiving cavity 214 formed by the side wall 212 and the first wall 211, which helps to reduce the damage to the electrode assembly 22 caused by the protrusion 2121 during the forming process, thereby improving the production quality of the cylindrical battery cell 20.

[0400] According to some embodiments of this application, as shown in Figures 6 and 7, the protrusion 2121 is a ring structure extending circumferentially along the sidewall 212, that is, the protrusion 2121 is a ring structure extending circumferentially along the sidewall 212 and connected end to end.

[0401] In this embodiment, by setting the protrusion 2121 as a ring structure with the ends connected, on the one hand, the support effect of the protrusion 2121 on the electrode assembly 22 through the first current collector 23 can be improved, and on the other hand, the protrusion 2121 can be connected to the docking part 232 at any position in its circumferential direction, which is beneficial to reduce the positioning difficulty and assembly difficulty between the docking part 232 and the protrusion 2121.

[0402] According to some embodiments of this application, please continue to refer to Figures 6 and 7. The pressure relief groove 2111 is an annular structure that extends circumferentially along the side wall 212. That is, the pressure relief groove 2111 is an annular structure that extends circumferentially along the side wall 212 and is connected end to end.

[0403] In this embodiment, by setting the pressure relief groove 2111 as an annular structure with the ends connected, the cylindrical battery cell 20 can completely open up the area of ​​the pressure relief component located in the pressure relief groove 2111 when the pressure is released, which is beneficial to increase the pressure relief area of ​​the cylindrical battery cell 20 and thus increase the pressure relief rate of the cylindrical battery cell 20.

[0404] According to some embodiments of this application, as shown in Figures 6 and 7, the pressure relief component is integrally formed with the first wall 211. That is, the pressure relief component and the first wall 211 are an integral structure, and the pressure relief component is a part of the first wall 211. Correspondingly, the pressure relief groove 2111 is a structure directly disposed on the first wall 211, such that the first wall 211 is configured to be able to crack along at least a portion of the pressure relief groove 2111 when the cylindrical battery cell 20 is depressurized, so as to release the internal pressure of the cylindrical battery cell 20.

[0405] In this embodiment, by setting the pressure relief component as an integral part of the first wall 211, the pressure relief component is a part of the first wall 211, so that the pressure relief groove 2111 is a structure directly set on the first wall 211. Therefore, there is no need to set up the assembly process between the pressure relief component and the first wall 211, which is beneficial to optimize the processing technology of the cylindrical battery cell 20 and improve the production efficiency of the cylindrical battery cell 20.

[0406] It should be noted that the structure of the cylindrical battery cell 20 is not limited to this. In other embodiments, the cylindrical battery cell 20 can also have other structures. For example, the pressure relief component and the first wall 211 can be separately arranged, with the pressure relief component connected to the first wall 211. That is, the pressure relief component and the first wall 211 are two independent components, and the pressure relief component and the first wall 211 are connected to each other. Correspondingly, the pressure relief groove 2111 is provided on the pressure relief component.

[0407] In this embodiment, by setting the pressure relief component as a separate structure from the first wall 211, the difficulty of directly machining the pressure relief groove 2111 on the first wall 211 can be reduced, and the impact on the structural strength of the first wall 211 can be reduced.

[0408] 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.

[0409] As shown in Figure 2, the battery device 100 may also include a housing 10, in which cylindrical battery cells 20 are housed.

[0410] 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.

[0411] 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.

[0412] 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.

[0413] 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.

[0414] 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.

[0415] 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.

[0416] 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.

[0417] The electrical device can be any of the aforementioned devices or systems that utilize cylindrical battery cells 20.

[0418] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0419] 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 casing includes a first wall and a side wall. The thickness direction of the first wall is the axial direction of the cylindrical battery cell. A pressure relief component is provided on the first wall, and the pressure relief component is provided with a pressure relief groove. The side wall surrounds the first wall, and a protrusion is provided on the inner circumferential surface of the side wall. Both the protrusion and the pressure relief groove extend along the circumferential direction of the side wall. An electrode assembly is housed within the housing and located on the side of the protrusion facing away from the first wall; as well as The first current collector includes a body portion and a docking portion. The body portion is located on the side of the electrode assembly facing the first wall and is connected to the electrode assembly. The body portion includes a main body area and a plurality of support areas connected to the outer peripheral surface of the main body area. The plurality of support areas are arranged circumferentially spaced along the main body area. At least a portion of the support areas is located between the electrode assembly and the protrusion in the thickness direction of the first wall. The docking portion is connected to the main body area and is connected to the protrusion to electrically connect the electrode assembly and the side wall. Wherein, along the radial direction of the cylindrical battery cell, the inner diameter of the protrusion is D1, the outer diameter of the main body area is D2, and the inner diameter of the pressure relief groove is D3, satisfying that D1≥D2 and D3≥0.75D2.

2. The cylindrical battery cell according to claim 1, wherein, D1≥D3.

3. The cylindrical battery cell according to claim 1 or 2, wherein, Along the radial direction of the cylindrical battery cell, the outer diameter of the body portion is D4, satisfying that D1≤0.95D4.

4. The cylindrical battery cell according to any one of claims 1-3, wherein, The maximum proportion of the multiple support areas in the circumferential direction of the main body area is P, which satisfies 40% ≤ P ≤ 90%.

5. The cylindrical battery cell according to claim 4, wherein, 50％≤P≤80％。 6. The cylindrical battery cell according to any one of claims 1-5, wherein, The protrusion protrudes radially from the inner circumferential surface of the sidewall of the cylindrical battery cell by a dimension L1. In the projection plane perpendicular to the thickness direction of the first wall, the portion of the orthographic projection of the support area overlapping the orthographic projection of the protrusion in the radial direction of the cylindrical battery cell has a dimension L2, satisfying 0.2L1≤L2≤0.9L1.

7. The cylindrical battery cell according to claim 6, wherein, 1mm≤L1≤8mm.

8. The cylindrical battery cell according to claim 6 or 7, wherein, L2≥1mm.

9. The cylindrical battery cell according to any one of claims 1-8, wherein, The thickness of the main body is T1, which satisfies 0.1mm≤T1≤0.6mm.

10. The cylindrical battery cell according to any one of claims 1-9, wherein, The electrode assembly includes a main body and a first electrode tab, and the first electrode tab is connected to the end of the main body facing the first wall along the thickness direction of the first wall; The main body area is welded to the first electrode tab to form a plurality of first connecting parts, and the plurality of supporting areas are welded to the first electrode tab to form a plurality of second connecting parts. The sum of the lengths of the plurality of second connecting parts is greater than or equal to the sum of the lengths of the plurality of first connecting parts.

11. The cylindrical battery cell according to claim 10, wherein, A plurality of the first connecting portions are arranged circumferentially along the sidewall, and the first connecting portions extend radially along the cylindrical battery cell.

12. The cylindrical battery cell according to claim 10 or 11, wherein, A plurality of second connecting portions are arranged circumferentially along the sidewall, and the second connecting portions extend radially along the cylindrical battery cell.

13. The cylindrical battery cell according to any one of claims 10-12, wherein, Each of the support areas is welded to the first electrode tab to form a second connection portion.

14. The cylindrical battery cell according to any one of claims 1-13, wherein, The first current collection component includes a plurality of docking portions, which are arranged at intervals along the circumference of the main body area and are all connected to the main body area. The plurality of docking portions are all connected to the protrusion.

15. The cylindrical battery cell according to claim 14, wherein, Multiple docking portions are welded to the protrusion and correspondingly form multiple third connecting portions. Each third connecting portion corresponds to one of the docking portions and extends circumferentially along the sidewall. In the projection plane perpendicular to the thickness direction of the first wall, the outer edges of the orthographic projections of the plurality of third connecting parts are all located on the first circle, and the sum of the arc lengths of the outer edges of the orthographic projections of the plurality of third connecting parts is L3, and the circumference of the first circle is L4, satisfying that L3≥0.5L4.

16. The cylindrical battery cell according to claim 15, wherein, L3≥0.8L4.

17. The cylindrical battery cell according to claim 15 or 16, wherein, The mating part has a connection area that is welded to the protrusion, and the connection area is an arc-shaped structure extending circumferentially along the sidewall.

18. The cylindrical battery cell according to any one of claims 14-17, wherein, Multiple docking parts are connected to the outer peripheral surface of the main body area, and the docking parts and the support area are alternately arranged along the circumference of the main body area.

19. The cylindrical battery cell according to any one of claims 1-18, wherein, The electrode assembly is provided with a central through hole, which extends through both ends of the electrode assembly along the thickness direction of the first wall. The main body area is provided with an exhaust hole, which extends through both sides of the main body area along the thickness direction of the first wall and is connected to the central through hole. Wherein, along the thickness direction of the first wall, the projection of the hole wall surface of the central through hole is located inside the exhaust hole.

20. The cylindrical battery cell according to claim 19, wherein, The diameter of the central through hole is D5, and the diameter of the vent hole is D6, satisfying that D6≥1.5D5.

21. The cylindrical battery cell according to any one of claims 1-20, wherein, Along the radial direction of the cylindrical battery cell, the length of the support region is L5, which satisfies 0.5D2≥L5.

22. The cylindrical battery cell according to any one of claims 1-21, wherein, The housing has an internal cavity, and the body is configured to divide the cavity into a first cavity and a second cavity that are in communication with each other. The electrode assembly is housed in the first cavity, and the second cavity is located between the body and the first wall in the thickness direction of the first wall. The pressure relief component is configured to split along at least a portion of the pressure relief groove when the cylindrical battery cell is depressurized, so as to release the internal pressure of the second cavity. Wherein, along the thickness direction of the first wall, the maximum size of the second cavity is H1, and the maximum size of the outer shell is H2, satisfying 0.003≤H1 / H2≤0.

06.

23. The cylindrical battery cell according to claim 22, wherein, 0.01≤H1 / H2≤0.

03.

24. The cylindrical battery cell according to claim 22 or 23, wherein, 0.4mm≤H1≤4mm.

25. The cylindrical battery cell according to any one of claims 22-24, wherein, The capacity of the cylindrical battery cell is C, which satisfies the condition 0.005mm / Ah ≤ H1 / C ≤ 0.2mm / Ah.

26. The cylindrical battery cell according to claim 25, wherein, The positive electrode material of the cylindrical battery cell includes lithium transition metal oxide, and H1 and C further satisfy the following condition: 0.01 mm / Ah ≤ H1 / C ≤ 0.2 mm / Ah; or The positive electrode material of the cylindrical battery cell includes lithium phosphate, and H1 and C further satisfy the condition that 0.005mm / Ah ≤ H1 / C ≤ 0.1mm / Ah.

27. The cylindrical battery cell according to any one of claims 22-26, wherein, Along the radial direction of the cylindrical battery cell, the outer diameter of the electrode assembly is D7, which satisfies 0.7≤D1 / D7≤0.

95.

28. The cylindrical battery cell according to claim 27, wherein, 0.75≤D1 / D7≤0.

9.

29. The cylindrical battery cell according to any one of claims 22-28, wherein, Along the thickness direction of the first wall, the projection of the pressure relief groove is located within the second cavity.

30. The cylindrical battery cell according to any one of claims 1-29, wherein, The docking part includes: A connecting area is provided on the side of the main body area facing the first wall in the thickness direction of the first wall, and the connecting area is connected to the protrusion; An elastic region, connecting the connecting region and the main body region, is configured to be deformable.

31. The cylindrical battery cell according to claim 30, wherein, The elastic region is bent to form multiple bent segments, which are connected sequentially, and the bent segments at both ends are respectively connected to the main body region and the connecting region.

32. The cylindrical battery cell according to claim 30 or 31, wherein, In a projection plane perpendicular to the thickness direction of the first wall, the orthographic projection of the connection area extends circumferentially along the side wall and is located on the periphery of the orthographic projection of the main body area. The orthographic projections of the connection area and the main body area are arranged radially spaced apart in the cylindrical battery cell to form an exhaust gap between the orthographic projections of the connection area and the main body area.

33. The cylindrical battery cell according to claim 32, wherein, Along the thickness direction of the first wall, at least a portion of the projection of the pressure relief groove lies within the exhaust gap.

34. The cylindrical battery cell according to claim 32 or 33, wherein, In the projection plane perpendicular to the thickness direction of the first wall, the diameter of the orthographic projection of the outer edge of the connecting area is D8, and the orthographic projection of the elastic area extends radially along the cylindrical battery cell with a length of L6, satisfying 1 / 15≤L6 / D8≤1 / 3.

35. The cylindrical battery cell according to claim 34, wherein, 1 / 7≤L6 / D8≤1 / 4.

36. The cylindrical battery cell according to claim 34 or 35, wherein, 3mm≤L6≤15mm.

37. The cylindrical battery cell according to any one of claims 32-36, wherein, The thickness of the elastic zone is T2. In a projection plane perpendicular to the thickness direction of the first wall, the width of the orthographic projection of the elastic zone in a direction perpendicular to its extension direction is W, satisfying 0.3mm. 2 ≤W×T2≤8mm 2 .

38. The cylindrical battery cell according to claim 37, wherein, 2mm≤W≤10mm.

39. The cylindrical battery cell according to claim 38, wherein, 3mm≤W≤5mm.

40. The cylindrical battery cell according to any one of claims 37-39, wherein, The thickness of the elastic zone is T2, which satisfies 0.15mm≤T2≤0.8mm.

41. The cylindrical battery cell according to claim 40, wherein, 0.3mm≤T2≤0.5mm.

42. The cylindrical battery cell according to any one of claims 30-41, wherein, The thickness of the elastic region is less than the thickness of the main body region; and / or The thickness of the elastic region is less than the thickness of the connecting region.

43. The cylindrical battery cell according to any one of claims 30-42, wherein, Along the thickness direction of the first wall, the connection area is disposed on the side of the protrusion away from the electrode assembly and is connected to the protrusion.

44. The cylindrical battery cell according to any one of claims 1-43, wherein, Along the radial direction of the cylindrical battery cell, a groove is formed on the side of the sidewall facing away from the electrode assembly and corresponding to the position of the protrusion.

45. The cylindrical battery cell according to any one of claims 1-44, wherein, The outer casing also includes: The second wall is disposed opposite to the first wall in the thickness direction of the first wall. The second wall is integrally formed with the side wall. Along the thickness direction of the first wall, one end of the side wall is connected to the second wall, and the other end is enclosed to form an opening. The side wall and the second wall together define a receiving cavity, and the electrode assembly is received in the receiving cavity. The first wall closes the opening.

46. ​​The cylindrical battery cell according to claim 45, wherein, The sidewall is bent at the end away from the second wall in the thickness direction of the first wall to form a flange, and the flange surrounds the opening; Wherein, along the thickness direction of the first wall, a portion of the first wall is located between the flange and the protrusion, and the flange and the protrusion are configured to cooperate in clamping the first wall.

47. The cylindrical battery cell according to claim 46, wherein, The cylindrical battery cell also includes: A seal, at least partially disposed radially between the sidewall and the first wall of the cylindrical battery cell, is configured to seal the gap between the first wall and the sidewall.

48. The cylindrical battery cell according to any one of claims 1-44, wherein, The sidewall is integrally formed with the first wall. Along the thickness direction of the first wall, one end of the sidewall is connected to the first wall, and the other end is enclosed to form an opening. The sidewall and the first wall together define a receiving cavity, and the electrode assembly is received in the receiving cavity. The outer casing further includes a second wall, which is disposed opposite to the first wall in the thickness direction of the first wall, and the second wall closes the opening.

49. The cylindrical battery cell according to any one of claims 1-48, wherein, The protrusion is a ring-shaped structure extending circumferentially along the sidewall.

50. The cylindrical battery cell according to any one of claims 1-49, wherein, The pressure relief groove is a ring-shaped structure that extends circumferentially along the sidewall.

51. The cylindrical battery cell according to any one of claims 1-50, wherein, The pressure relief component is integrally formed with the first wall.

52. The cylindrical battery cell according to any one of claims 1-50, wherein, The pressure relief component is separately disposed from the first wall, and the pressure relief component is connected to the first wall.

53. A battery device comprising a cylindrical battery cell as claimed in any one of claims 1-52.

54. An electrical device comprising a cylindrical battery cell as described in any one of claims 1-52, the cylindrical battery cell being used to provide electrical energy.

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