Cylindrical battery cell, battery device, and electrical device

Abstract

The present application relates to the field of batteries, and discloses a cylindrical battery cell (100), a battery device (1000), and an electrical device. The cylindrical battery cell (100) comprises a casing (20) and an electrode assembly (10). The casing (20) is provided with a pressure relief portion (22111). The electrode assembly (10) has a winding structure and comprises two electrode sheets (1). At least one of the electrode sheets (1) comprises an electrode sheet main body (11) and a tab (12) arranged in a first direction (Z). The tab (12) comprises a plurality of tab winding portions (121) distributed along a winding direction of the electrode assembly, and a first cut-off groove (102) extending for at least one winding turn is provided between two adjacent tab winding portions (121). The first cut-off groove (102) passes through an end surface of the tab (12) away from the electrode sheet main body (11). In this way, the efficiency of directional pressure relief can be improved.

Description

Cylindrical battery cells, battery packs and electrical devices Technical Field

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

[0002] From a market perspective, the application of battery devices is becoming increasingly widespread. Battery devices are not only used in energy storage systems such as hydropower, thermal power, wind power, and solar power plants, but also extensively in electric vehicles such as electric bicycles, electric motorcycles, and electric cars, as well as in military equipment and aerospace. As the application areas of battery devices continue to expand, the market demand is also constantly increasing. Furthermore, the capacity of battery devices is becoming larger, and the performance requirements for battery devices are becoming increasingly stringent.

[0003] In related technologies, battery devices typically include one or more battery cells. During the use of a battery cell, external short circuits, overcharging, punctures, or flat-plate impacts can easily trigger thermal runaway.

[0004] For cylindrical battery cells, in some cases, the tabs of the cell generally have a significant binding effect, which strongly hinders the flow of high-temperature, high-pressure media. Therefore, during thermal runaway, the high-temperature, high-pressure media generated in a cylindrical battery cell spreads towards the pressure relief mechanism at a slower rate, resulting in lower efficiency for directional pressure relief through the mechanism.

[0005] The above statements are for the purpose of providing background information in relation to this application only and do not necessarily constitute prior art. Summary of the Invention

[0006] In view of the above problems, the purpose of this application is to provide a cylindrical battery cell, a battery device and an electrical device that can improve the technical problem of low directional pressure relief efficiency of cylindrical battery cells.

[0007] The technical solution adopted in the embodiments of this application is:

[0008] In a first aspect, embodiments of this application provide a cylindrical battery cell, comprising:

[0009] The housing has a pressure relief section at at least one end along a first direction, and the pressure relief section is configured to open at least partially when pressure is released;

[0010] An electrode assembly is at least partially disposed within a housing; the electrode assembly has a wound structure and includes two electrodes with opposite polarities; at least one electrode includes an electrode body and an electrode tab arranged along a first direction, the electrode body is coated with an active material layer, and at least a portion of the electrode tab is not coated with an active material layer; on a projection plane perpendicular to the first direction, at least a portion of the electrode tab is projected into the projection of the pressure relief portion.

[0011] The tab includes multiple tab winding portions distributed along the winding direction of the electrode assembly. A first cutting groove is provided between two adjacent tab winding portions. The first cutting groove penetrates the end face of the tab away from the electrode body. The first cutting groove is wound at least one turn along the winding direction of the electrode assembly.

[0012] The cylindrical battery cell provided in this application embodiment includes a plurality of tab winding portions distributed along the winding direction of the electrode assembly. A first cutting groove is provided between any two adjacent tab winding portions along the winding direction of the electrode assembly. The first cutting groove penetrates the end face of the tab away from the electrode body and is wound at least once along the winding direction, so that the plurality of tab winding portions are disconnected through the first cutting groove. Under the action of the first cutting groove wound at least once, the mutual binding effect between the plurality of tab winding portions is weakened, and the mutual binding effect between the plurality of electrode winding portions with tab winding portions and the binding effect between the electrode winding portions and the electrode coil portion are also weakened. By providing a pressure relief section at at least one end of the outer casing along a first direction, and configuring the pressure relief section to at least partially open during pressure relief to form an exhaust channel, the binding force between the multiple tab windings is easily broken under air pressure during thermal runaway of the cylindrical battery cell. The mutual binding force between the multiple electrode windings, and the binding force between the electrode windings and the electrode coils, are also easily broken. This allows at least the portion of the electrode facing the pressure relief section to easily loosen under air pressure, and even be released outside the casing through the pressure relief section. This reduces the obstruction of the tabs to the high-temperature, high-pressure medium, facilitating the spread of the high-temperature, high-pressure medium towards the pressure relief section and its release outside the casing through the exhaust channel formed by the opening of the pressure relief section. Thus, the discharge rate and efficiency of the high-temperature, high-pressure medium can be improved, enabling the cylindrical battery cell to achieve efficient directional pressure relief, thereby contributing to improved reliability of the cylindrical battery cell.

[0013] In some embodiments, among the plurality of electrode winding portions, the innermost electrode winding portion along the winding direction of the electrode assembly is the first electrode winding portion, and at least a portion of the orthographic projection of the first electrode winding portion is located within the orthographic projection of the pressure relief portion on a projection plane perpendicular to the first direction.

[0014] With this configuration, during the thermal runaway of a cylindrical battery cell, the binding force between the first tab winding portion and other tab winding portions can be easily broken under the action of air pressure. This allows at least a portion of the electrode sheet to loosen under the action of air pressure, and even be released outside the casing through the exhaust channel formed by the opening of the pressure relief portion. This facilitates the loosening and even release of the electrode sheet, which helps the cylindrical battery cell achieve an efficient directional pressure relief effect.

[0015] In some embodiments, on a projection plane perpendicular to the first direction, the orthographic projection of the first pole ear winding portion is located within the orthographic projection of the pressure relief portion.

[0016] This design allows the electrode 1 to loosen under air pressure during the depressurization process of the cylindrical battery cell, and even release the pressure through the exhaust channel formed by the opening of the depressurization part to the outside of the casing, which helps to improve the directional depressurization effect of the cylindrical battery cell.

[0017] In some embodiments, the electrode includes a plurality of first cut-off grooves, and on a projection plane perpendicular to the first direction, at least a portion of the orthographic projection of the bottom surface of the first groove of the innermost first cut-off groove is located within the orthographic projection of the pressure relief portion.

[0018] Alternatively, the electrode includes a first cut-off groove, and on a projection plane perpendicular to the first direction, at least a portion of the orthographic projection of the bottom surface of the first cut-off groove lies within the orthographic projection of the pressure relief section.

[0019] By adopting the above technical solution, the electrode sheets can be loosened under air pressure and released outside the casing through the exhaust channel, which helps the cylindrical battery cell achieve a highly efficient directional pressure relief effect and improves the problem of low directional pressure relief efficiency of the cylindrical battery cell.

[0020] In some embodiments, the electrode includes a first electrode lug winding portion formed at one end of the first electrode winding portion along a first direction, and a pressure relief portion is configured to at least partially open and form an exhaust passage when pressure is relieved, through which at least a portion of the first electrode winding portion is discharged to the outside of the housing.

[0021] By adopting the above technical solution, during the thermal runaway of a cylindrical battery cell, the first electrode winding portion can be released to the outside of the casing under gas pressure through the exhaust channel, thus reducing the obstruction effect of the electrode tab on the high-temperature and high-pressure medium. In this process, on the one hand, the high-temperature and high-pressure medium generated inside the cylindrical battery cell can be discharged to the outside of the casing along with the first electrode winding portion; on the other hand, a large channel is formed in the area of ​​the electrode facing the pressure relief section, and this channel gradually enlarges as the first electrode winding portion releases pressure, facilitating the discharge of the high-temperature and high-pressure medium. This improves the discharge efficiency of the high-temperature and high-pressure medium, enabling the cylindrical battery cell to achieve efficient directional pressure relief, thereby contributing to improved reliability.

[0022] In some embodiments, at least one electrode has a winding start end and a winding end end at both ends along the winding direction of the electrode assembly. The winding start end is formed in the winding portion of the first electrode, and the orthographic projection of the winding start end is located within the orthographic projection of the pressure relief portion on a projection plane perpendicular to the first direction.

[0023] With this configuration, when the pressure inside the casing reaches a threshold, at least a portion of the first electrode winding near the starting end of the winding can be released to the outside of the casing through the exhaust channel. This facilitates the first electrode winding to loosen under air pressure and release through the exhaust channel, which helps to improve the directional pressure relief efficiency of the cylindrical battery cell.

[0024] In some embodiments, the tabs are provided with a central hole extending along a first direction, and each tab winding portion is disposed around the outer periphery of the central hole. On a projection plane perpendicular to the first direction, the orthographic projection of the central hole is located within the orthographic projection of the pressure relief portion.

[0025] Thus, the central hole facilitates the loosening of the electrode under air pressure and allows the electrode to be released outside the outer casing, thereby facilitating exhaust and achieving a highly efficient directional pressure relief effect.

[0026] This configuration allows at least a portion of the electrode adjacent to the central hole to be gradually released to the outside of the casing through the venting channel formed by the pressure relief section during the thermal runaway of the cylindrical battery cell, thereby helping to improve the pressure relief efficiency of the cylindrical battery cell.

[0027] In some embodiments, the outer diameter of the electrode assembly is D1, the diameter of the central hole is D2, and D2 / D1 ∈ [5%, 25%].

[0028] This design allows the central hole to have a large diameter, which facilitates the discharge of the high-temperature and high-pressure medium inside the cylindrical battery cell to the pressure relief section through the central hole during thermal runaway, thereby achieving an efficient directional pressure relief effect.

[0029] In some embodiments, the number of turns of the first cut-off groove along the winding direction of the electrode assembly is ∈ [2, 4].

[0030] This can improve the discharge rate and efficiency of high-temperature and high-pressure media, enabling cylindrical battery cells to achieve efficient directional pressure relief, thereby helping to improve the reliability of cylindrical battery cells.

[0031] In some embodiments, both electrodes include an electrode body and an electrode tab, the electrode tabs of the two electrodes are respectively disposed at both ends of the electrode assembly along the first direction, and the electrode tab of each electrode includes a plurality of electrode tab winding portions.

[0032] This configuration allows at least a portion of the electrode assembly directly opposite the pressure relief section to be released outside the casing through the exhaust channel under air pressure, achieving a highly efficient directional pressure relief effect and thus contributing to the reliability of the cylindrical battery cell.

[0033] In some embodiments, the two electrodes include a positive electrode and a negative electrode, wherein the tabs of the positive electrode and / or the tabs of the negative electrode are not coated with an active material layer.

[0034] If at least one of the positive and negative electrode plates has no active material layer coated on the tab, then during the process of cutting the tab to form the tab winding portion and the first cutting groove, only the tab is cut and not the main body of the electrode plate. Therefore, the part of the electrode plate with the active material layer is not cut, so the first cutting groove is formed in the part of the electrode plate without the active material layer. This can ensure the performance of the active material layer to a certain extent, thereby ensuring the performance of the electrode assembly to a certain extent, and thus the charge and discharge performance of the cylindrical battery cell.

[0035] In some embodiments, the electrode assembly has a winding axis parallel to a first direction, and at least one tab winding portion has a bent section at one end in the first direction.

[0036] The bending section includes a first bending portion that is bent relative to the electrode body in a direction close to the winding axis, and / or the bending section includes a second bending portion that is bent relative to the electrode body in a direction away from the winding axis.

[0037] This design allows the end region of the tab winding portion away from the electrode body along the first direction to be bent, thereby forming a relatively dense stacked layer. This reduces the gap between the tab layers in the tab winding portion, facilitating welding between the tab winding portion and the current collector. Furthermore, the bending of the tab provides a strong binding effect on the electrode, resulting in higher structural integrity and performance of the electrode assembly.

[0038] In some embodiments, each tab winding has a bent section at one end in a first direction.

[0039] This configuration allows the end region of the tab away from the electrode body along the first direction to be bent effectively, thereby forming a relatively dense stacked layer.

[0040] In some embodiments, at least one electrode has a winding start end and a winding end end at its two ends along the winding direction of the electrode assembly;

[0041] Among the multiple electrode winding sections, the innermost electrode winding section is provided with a first notch groove. The first notch groove passes through the winding start end along the winding direction of the electrode assembly and passes through the end face of the electrode winding section away from the electrode body.

[0042] On the projection plane perpendicular to the first direction, the orthographic projection of the bottom surface of the third groove of the first notch is located within the orthographic projection of the pressure relief part.

[0043] By placing the orthographic projection of the bottom surface of the third groove of the first notch on a projection plane perpendicular to the first direction within the orthographic projection of the pressure relief portion, the electrode winding portion (which may be the first electrode winding portion) with the first notch is also positioned directly opposite the pressure relief portion along the first direction. This reduces the binding effect of the electrode winding portion with the first notch, facilitating the release of pressure to the outside of the casing through the pressure relief portion during thermal runaway, thereby improving the directional pressure relief efficiency of the cylindrical battery cell.

[0044] In some embodiments, the cylindrical battery cell further includes a current collector, at least a portion of which is disposed within the housing;

[0045] The tab winding section has a winding start section located at one end of the first notch near the electrode body, and the bottom surface of the third groove is the end face of the winding start section away from the electrode body. The current collector is welded to the part of the tab winding section that extends beyond the bottom surface of the third groove in the direction away from the electrode body, and is not welded to the winding start section.

[0046] By welding the current collector to the portion of the electrode winding portion that extends beyond the bottom of the third groove, and not welding it to the winding start section, the binding effect of the portion of the electrode winding portion with the first notch is reduced. This facilitates the release of pressure through the pressure relief section of the electrode winding portion with the first notch during the thermal runaway of the cylindrical battery cell, thereby improving the directional pressure relief efficiency of the cylindrical battery cell.

[0047] In some embodiments, at least one electrode has a winding start end and a winding end end at its two ends along the winding direction of the electrode assembly;

[0048] Among the multiple electrode winding sections, the outermost electrode winding section is provided with a second notch. The second notch penetrates the winding end along the winding direction of the electrode assembly and penetrates the end face of the electrode away from the electrode body.

[0049] This design allows the second notch to form a channel for venting. Furthermore, the binding effect of the electrode winding with the second notch is reduced, making it easier for the winding to loosen or even eject from the pressure relief section during thermal runaway. This, in turn, improves the directional pressure relief efficiency of the cylindrical battery cell.

[0050] In some embodiments, the cylindrical battery cell further includes a current collector, at least a portion of which is disposed within the housing;

[0051] The tab winding section has a winding end section located at one end of the second notch near the electrode body. The bottom surface of the fourth groove of the second notch is the end face of the winding end section away from the electrode body. The current collector is welded to the part of the tab winding section that extends beyond the bottom surface of the fourth groove in the direction away from the electrode body, and is not welded to the winding end section.

[0052] By welding the current collector to the portion of the electrode winding that extends beyond the bottom of the fourth groove, and not welding it to the end of the winding, the binding effect of the portion of the electrode winding with the second notch is reduced. This makes it easier for the electrode winding with the second notch to release pressure through the pressure relief section under the action of air pressure during the thermal runaway of the cylindrical battery cell, thereby improving the directional pressure relief efficiency of the cylindrical battery cell.

[0053] In some embodiments, at least one tab winding portion includes a plurality of segments distributed along the winding direction of the electrode assembly, and a second cutting groove is provided between any two adjacent segments in the tab winding portion along the winding direction of the electrode assembly.

[0054] On the projection plane perpendicular to the first direction, the orthographic projection of the bottom surface of at least one second cut-off groove is located within the orthographic projection of the pressure relief section.

[0055] In this way, under the action of the second cutting groove, the self-binding effect of at least one electrode lug winding portion facing the pressure relief portion is weakened, thereby weakening the self-binding effect of at least one electrode winding portion as well. This helps the cylindrical battery cell achieve efficient directional pressure relief, improving the problem of low directional pressure relief efficiency in cylindrical battery cells, and thus contributing to improved reliability.

[0056] In some embodiments, the plurality of electrode winding portions include adjacent first electrode winding portions and second electrode winding portions, wherein the second electrode winding portion is disposed on the outside of the first electrode winding portion;

[0057] The first electrode winding portion includes multiple segments. On a projection plane perpendicular to the first direction, the orthographic projection of the bottom surface of at least one second cutting groove in the first electrode winding portion is located within the orthographic projection of the pressure relief portion.

[0058] By adopting the above technical solution, the self-binding effect of the first electrode winding part is weakened by the setting of the second cutting groove. In this way, when the pressure value inside the shell reaches the threshold, the first electrode winding part can be released to the outside of the shell through the pressure relief part, so that the cylindrical battery cell can achieve a highly efficient directional pressure relief effect.

[0059] In some embodiments, the plurality of electrode winding portions include adjacent first electrode winding portions and second electrode winding portions, wherein the second electrode winding portion is disposed on the outside of the first electrode winding portion;

[0060] The second electrode winding portion includes multiple segments, among which the segment closest to the first electrode winding portion is wound at least three times.

[0061] This configuration allows the segment closest to the first cut-off groove in the second electrode winding section to effectively wrap around the first cut-off groove, thus mitigating the problem of electrode collapse caused by the first cut-off groove. This enhances the overall binding effect of the electrode and gives the electrode assembly higher performance.

[0062] In some embodiments, among the multiple segments of the second electrode ear winding portion, the segment closest to the first electrode ear winding portion has ≤8 turns.

[0063] This configuration allows the segment closest to the first cut-off groove in the second electrode winding section to effectively wrap around the first cut-off groove, thus mitigating the problem of electrode collapse caused by the first cut-off groove. On the other hand, it also allows the second cut-off groove to be formed in the second electrode winding section, which helps to improve the directional pressure relief efficiency of the cylindrical battery cell.

[0064] In some embodiments, the two electrodes include a positive electrode and a negative electrode, the tabs of the positive electrode and / or the tabs of the negative electrode are not coated with an active material layer, and in a first direction, an insulating layer is provided in the end region of the tab near the electrode body, and the cut-off piece is located on the side of the insulating layer away from the electrode body.

[0065] This design provides an insulating layer on the positive electrode 1a, which effectively improves the short circuit problem between the positive and negative electrodes.

[0066] In some embodiments, at least one tab winding portion includes a transition connection portion and a slit, wherein the electrode body, the transition connection portion and the slit are arranged sequentially along a first direction, wherein in the tab winding portion, the transition connection portion and two slits adjacent to each other along the winding direction of the electrode assembly form a second cutting groove, and the bottom surface of the second cutting groove is formed on one side edge of the transition connection portion for connecting the slits.

[0067] The transition connection between the electrode body and the cut-off piece allows the electrode body and the cut-off piece to be spaced apart along a first direction, and the electrode body and the second cutting groove to be spaced apart along the first direction as well. This facilitates avoiding the electrode body during the cutting of the electrode lug winding portion to form the second cutting groove and the cut-off piece, thus preventing the electrode body from being cut to some extent. Furthermore, it solves the problem of the electrode body being easily torn due to the bottom surface of the second cutting groove being formed on one side edge of the electrode body. On the other hand, the transition connection can block the cut-off piece, thus isolating it from the main body of the electrode assembly. This improves the problem of short circuits in the electrode assembly caused by the cut-off piece being bent and inserted into the main body, reducing the risk of short circuits.

[0068] In some embodiments, the dimension of one side edge of each segment used to connect the transition connection portion in the winding direction of the electrode assembly is H1, and the dimensions of the transition connection portion and the segment in the first direction are H2, where 0.01≤H2 / H1≤0.3.

[0069] This design allows the cut sheet to have a larger size in the winding direction, which facilitates the winding of the cut sheet and, to a certain extent, ensures the structural integrity of the electrode assembly and, to a certain extent, the charging and discharging performance of the cylindrical battery cell.

[0070] In some embodiments, the dimension of the transition connection in the first direction is H3, where 0.1mm≤H3≤2mm.

[0071] With this configuration, the second cutting groove can be formed in the electrode winding section, and the transition connection section has a suitable width in the first direction to block the cutting piece, which can improve the problem of the cutting piece bending and inserting into the main body.

[0072] In some embodiments, at least one electrode has a winding start end and a winding end end at both ends along the winding direction of the electrode assembly, and among the plurality of electrode lug winding portions, the winding end is formed at the outermost electrode lug winding portion along the winding direction of the electrode assembly.

[0073] Among the multiple tab winding portions, along the winding direction of the electrode assembly, the outermost tab winding portion includes multiple segments, and the segment closest to the winding end is wound at least one turn.

[0074] By winding the piece closest to the winding end at least once, the piece closest to the winding end can effectively wrap around the other pieces. This can improve the problem of internal short circuits caused by the pieces turning outward and inserting into the main body, thereby reducing the risk of short circuits.

[0075] In some embodiments, at least one tab winding portion is provided with a plurality of second cut-off grooves, and in the tab winding portion, each second cut-off groove and each piece are alternately arranged along the winding direction of the electrode assembly.

[0076] By forming multiple second cut-off grooves on the electrode lug winding section, a larger removal ratio can be achieved, allowing the portion of the electrode lug winding section with the second cut-off grooves to release pressure through the pressure relief section during thermal runaway, thus achieving a highly efficient directional pressure relief effect. Furthermore, the deposited layer formed by bending the portion of the electrode lug winding section with the second cut-off grooves is not too thin, effectively blocking the laser generated during welding, thereby achieving a protective effect on the diaphragm.

[0077] In some embodiments, in the first direction, the size of the truncated sheet along the winding direction of the electrode assembly tends to decrease in the direction away from the electrode body.

[0078] By gradually decreasing the size of the truncated section along the winding direction away from the electrode body in the first direction, it helps to reduce the binding effect of the accumulated layer formed by bending in the end region of the truncated section away from the electrode body. This helps the portion of the electrode with the second cut-off groove to loosen during thermal runaway and release pressure through the pressure relief section. Furthermore, the first cut-off groove facilitates the easy loosening of at least one electrode winding portion from other electrode winding portions under pressure, and even allows for pressure relief through the pressure relief section. Based on this, it helps to improve the directional pressure relief efficiency.

[0079] In some embodiments, the electrode assembly has a winding axis parallel to a first direction, and at least one segment has a bent section at one end in the first direction.

[0080] The bending section includes a first bending portion that is bent relative to the electrode body in a direction close to the winding axis, and / or the bending portion includes a second bending portion that is bent relative to the electrode body in a direction away from the winding axis.

[0081] This configuration allows the end region of the tab away from the electrode body along the first direction to be bent to form a relatively dense stacked layer, thereby enabling the tab to form a stacked layer along the end region away from the electrode body along the first direction.

[0082] In some embodiments, each segment has a bent end at one end in the first direction.

[0083] This configuration allows each segment of the tab to be bent, enabling the end region of the tab away from the main body of the electrode to be bent along the first direction, thereby forming a stacked layer.

[0084] In some embodiments, the first bending portion is bent radially along the electrode assembly; and / or, the second bending portion is bent radially along the electrode assembly.

[0085] This configuration allows the bent section to bend radially, enabling the tabs to be bent more effectively and form a deposit layer.

[0086] In some embodiments, the bending segment includes at least one first bending portion and at least one second bending portion, wherein the first bending portion and the second bending portion are alternately arranged along a first direction.

[0087] This configuration allows the end region of the tab that is away from the electrode body along the first direction to be bent, thereby forming a relatively dense stacked layer.

[0088] In some embodiments, the tab further includes a tab loop portion, which is connected between two adjacent tab winding portions along the winding direction of the electrode assembly, and the tab loop portion and the two adjacent tab winding portions along the winding direction of the electrode assembly surround to form a first cut-off groove.

[0089] This design allows the tab coil to block the tab winding section, which can improve the problem of internal short circuit caused by the tab winding section bending and inserting into the main body, thereby reducing the risk of short circuit.

[0090] In some embodiments, the cylindrical battery cell further includes a current collector, at least a portion of which is disposed within the housing; the current collector is welded to the tab winding portion to form a first weld portion; the current collector is not welded to the tab coil portion.

[0091] By welding the current collector to the tab winding portion of the electrode, but not to the tab coil portion, the self-binding effect of the tab coil portion is weakened, and the self-binding effect of the electrode coil portion is also weakened. This reduces the mutual binding effect between adjacent tab winding portions and adjacent electrode winding portions. Consequently, when the pressure inside the casing reaches a threshold, the electrodes can easily loosen under pressure and even release pressure through the venting section to the outside of the casing, contributing to a highly efficient directional pressure relief effect in the cylindrical battery cell.

[0092] In some embodiments, on a projection plane perpendicular to the first direction, the two ends of the orthographic projection of the first weld portion have a first projection endpoint and a second projection endpoint, respectively. The first projection endpoint is closer to the winding axis parallel to the first direction than the second projection endpoint. The area between the first arc line passing through the first projection endpoint and surrounding the winding axis and the second arc line passing through the second projection endpoint and surrounding the winding axis is the first transverse area.

[0093] At least one tab winding portion includes a plurality of segments distributed along the winding direction of the electrode assembly, and in the tab winding portion, a second cutting groove is provided between any two adjacent segments along the winding direction of the electrode assembly, and at least some of the second cutting grooves form a first group of grooves, in which the orthographic projection of the bottom surface of the second groove of all the second cutting grooves is located within a first transverse region.

[0094] The current collector is welded to the section to form the first welded part;

[0095] Wherein, in the first group of slots, the number of turns of a single second cut-off slot is ≤3; and / or, in the first group of slots, the number of second cut-off slots that are radially opposite and connected along the electrode assembly is ≤3.

[0096] By adopting the above technical solution, based on the provision of a second cutting groove in the portion of the electrode winding where the first welding portion is formed, the stacked layer formed by bending in the portion of the electrode winding where the first welding portion is formed will not be too thin due to the setting of the second cutting groove. This allows the portion of the electrode winding where the first welding portion is formed to bear the welding penetration of the current collector and the electrode, which can improve the problem of laser penetration of the electrode and burning of the diaphragm during the welding process of the current collector and the electrode. This can improve the problem of short circuit of the electrode assembly caused by the welding of the current collector and the electrode, and reduce the risk of short circuit.

[0097] In some embodiments, the cylindrical battery cell further includes electrode terminals fixed to the housing, which are welded to the current collector to form a second welded portion.

[0098] This configuration allows for electrical connection between the electrode terminals and the electrode assembly.

[0099] In some embodiments, on the projection plane perpendicular to the first direction, the two ends of the orthographic projection of the second weld portion have a third projection endpoint and a fourth projection endpoint, respectively. The third projection endpoint is closer to the winding axis parallel to the first direction than the fourth projection endpoint. The area between the third arc line that passes through the third projection endpoint and surrounds the winding axis and the fourth arc line that passes through the fourth projection endpoint and surrounds the winding axis is the second transverse area.

[0100] At least one tab winding portion includes a plurality of segments distributed along the winding direction of the electrode assembly, and in the tab winding portion, a second cutting groove is provided between any two adjacent segments along the winding direction of the electrode assembly, and at least a portion of the second cutting grooves form a second group of grooves, in which the orthographic projection of the bottom surface of the second groove of all the second cutting grooves is located within the second transverse region.

[0101] Wherein, in the second set of slots, the number of turns of a single second cut-off slot is ≤3; and / or, in the second set of slots, the number of second cut-off slots that are radially opposite and interconnected along the electrode assembly is ≤3.

[0102] By adopting the above technical solution, based on the provision of a second cutting groove in the portion of the electrode winding where the second welding portion is formed, the deposited layer formed by bending in the portion of the electrode winding where the second welding portion is formed will not be too thin due to the setting of the second cutting groove. This allows the portion of the electrode winding where the second welding portion is formed to bear the welding penetration of the current collector and the electrode terminal, which can improve the problem of laser penetration of the electrode and burning of the diaphragm during the welding process of the current collector and the electrode terminal. This can improve the problem of short circuit of the electrode assembly caused by welding of the current collector and the electrode terminal, and reduce the risk of short circuit.

[0103] In some embodiments, at least one electrode has a winding start end and a winding end end at its two ends along the winding direction of the electrode assembly;

[0104] In the multiple tab winding sections, along the winding direction of the electrode assembly, the innermost tab winding section is provided with a first notch groove. The first notch groove passes through the winding start end along the winding direction of the electrode assembly and passes through the end face of the tab winding section away from the electrode body. On the projection plane perpendicular to the first direction, the orthographic projection of the bottom surface of the third groove of the first notch groove is located within the orthographic projection of the pressure relief section.

[0105] In the radial direction of the electrode assembly, a first weld portion is located outside the first notch groove; and / or, in the radial direction of the electrode assembly, a second weld portion is located outside the first notch groove.

[0106] The above measures can improve the problem of laser penetration of the electrode tab and burning of the diaphragm during the welding process, thereby improving the short circuit problem of the electrode assembly and reducing the risk of short circuit.

[0107] In some embodiments, at least one electrode has a winding start end and a winding end end at its two ends along the winding direction of the electrode assembly;

[0108] In the multiple tab winding sections, along the winding direction of the electrode assembly, the outermost tab winding section is provided with a second notch. The second notch penetrates the winding end along the winding direction of the electrode assembly and penetrates the end face of the tab winding section away from the electrode body.

[0109] In the radial direction of the electrode assembly, the second notch is located outside the first weld portion; and / or, in the radial direction of the electrode assembly, the second notch is located outside the second weld portion.

[0110] The above measures can improve the problem of laser penetration of the electrode tab and burning of the diaphragm during the welding process, thereby improving the short circuit problem of the electrode assembly and reducing the risk of short circuit.

[0111] In some embodiments, both electrodes include an electrode body and an electrode tab, wherein the electrode tab of one electrode is a first electrode tab and the electrode tab of the other electrode is a second electrode tab. The first electrode tab and the second electrode tab are respectively disposed at both ends of the electrode assembly along a first direction, and both the first electrode tab and the second electrode tab include multiple electrode tab winding portions.

[0112] In the first direction, both ends of the electrode assembly are provided with current collecting components, and the current collecting components at both ends of the electrode assembly are the first current collecting component and the second current collecting component, respectively.

[0113] The housing includes a second end wall, a first end wall, and a side wall. The second end wall and the first end wall are respectively located at both ends of the side wall along a first direction, and electrode terminals are provided on the second end wall.

[0114] The first current collector is welded to the tab winding portion of the first electrode and electrically connected to the electrode terminal; the second current collector is welded to the tab winding portion of the second electrode and electrically connected to the side wall.

[0115] By adopting the above technical solution, at least one of the sidewall, the first endwall, and the second endwall can serve as one current transmission terminal of the cylindrical battery cell, and the electrode terminal serves as the other current transmission terminal of the cylindrical battery cell. That is, the electrode terminal and the outer casing can serve as two current transmission terminals of the cylindrical battery cell.

[0116] In some embodiments, the second current collector is welded to the first end wall, and the side wall is electrically connected to the first end wall.

[0117] This configuration allows the second current collector to be indirectly electrically connected to the sidewall via the first end wall.

[0118] In some embodiments, a protrusion is formed inwardly on the sidewall of the electrode assembly in the radial direction; the protrusion and the electrode assembly are distributed along a first direction, and a second current collector is welded to the side of the protrusion close to or away from the electrode assembly.

[0119] This configuration allows the second current collector to be directly electrically connected to the sidewall.

[0120] In some embodiments, the first electrode is a positive electrode and the second electrode is a negative electrode.

[0121] By adopting the above technical solution, the electrode terminal is a positive electrode terminal, and at least one of the first end wall, the second end wall, and the side wall is a negative current transmission terminal of the cylindrical battery cell.

[0122] In some embodiments, a pressure relief portion is provided on the first end wall.

[0123] By adopting the above technical solution, the pressure relief section and the electrode terminals are respectively located at both ends of the outer casing along the first direction, which facilitates the layout of the pressure relief section and the electrode terminals and helps to improve the efficiency of assembling multiple cylindrical battery cells into a group.

[0124] In some embodiments, the current collecting member is provided with an exhaust port extending in a first direction, and the exhaust port and the pressure relief portion are disposed opposite to each other in the first direction; the current collecting member is provided with a plurality of guide portions, which are spaced apart around the outer periphery of the exhaust port.

[0125] By adopting the above technical solution, during the thermal runaway of a cylindrical battery cell, when the pressure inside the casing reaches a threshold, the pressure relief section can open under the action of air pressure to form an exhaust channel. The guide section can also deform and open towards the pressure relief section near the exhaust port under the action of air pressure, thereby gradually increasing the diameter of the exhaust port. This facilitates the movement of the electrode winding section towards the pressure relief section, allowing the pressure to be released sequentially through the exhaust port and exhaust channel to the outside of the casing. This design helps improve the directional pressure relief efficiency of the cylindrical battery cell.

[0126] In some embodiments, the guide portion extends to the vent hole; or, the guide portion is spaced apart from the wall of the vent hole, and the minimum distance between the guide portion and the wall of the vent hole is less than or equal to 10 mm.

[0127] This design allows the guide section to deform and open the portion of the flow collector near the exhaust port towards the pressure relief section during pressure relief, thereby increasing the size of the exhaust port and achieving a highly efficient directional pressure relief effect.

[0128] In some embodiments, on a projection plane perpendicular to the first direction, along the radial direction of the electrode assembly, the orthographic projection of the end of the guide portion away from the exhaust port is located outside the outer contour of the orthographic projection of the pressure relief portion or coincides with the outer contour of the orthographic projection of the pressure relief portion.

[0129] By adopting the above technical solution, the guide portion, under the action of air pressure, can deform and open the current collector component toward the pressure relief portion, and the diameter of the exhaust orifice can be increased to a greater extent. Thus, during the thermal runaway of a cylindrical battery cell, when at least a portion of the electrode is released to the outside of the casing through the exhaust channel formed by the opening of the pressure relief portion, the obstruction effect of the current collector component on the electrode can be reduced, which helps to improve the efficiency of the electrode releasing pressure through the exhaust channel, thereby improving the directional pressure relief efficiency of the cylindrical battery cell.

[0130] In some embodiments, the guide portion includes a through hole extending through the current collector in a first direction; and / or, the guide portion includes a second groove that does not extend through the current collector in the first direction.

[0131] By adopting the above technical solution, the guide part can guide the part of the current collector near the exhaust hole to deform and open towards the pressure relief part during thermal runaway, thereby helping the cylinder to improve the directional pressure relief effect of the battery cell.

[0132] In some embodiments, the electrode assembly has a central hole extending in a first direction, the electrode lug is arranged around the outer periphery of the central hole, and the exhaust port is opposite to and communicates with the central hole along the first direction; on a projection plane perpendicular to the first direction, the orthographic projection of the central hole is located within the orthographic projection of the pressure relief portion.

[0133] With this configuration, when the pressure inside the casing reaches the threshold and the pressure relief section opens to form an exhaust channel, the central hole, exhaust through hole, and exhaust channel are connected sequentially along the first direction, which facilitates exhaust and helps improve the efficiency of directional pressure relief.

[0134] In some embodiments, the housing further includes a first end wall opposite to the electrode assembly along a first direction, the first end wall having a first groove and a pressure relief portion located in the area enclosed by the first groove, the bottom of the first groove having a weak portion, the pressure relief portion being connected to the weak portion, at least a portion of the weak portion being configured to be disconnected during pressure relief to open the pressure relief portion.

[0135] By adopting the above technical solution, the pressure relief section can be opened to form an exhaust channel when the pressure value inside the cylindrical battery cell reaches a threshold, thereby facilitating at least a portion of the electrode sheet to be released to the outside of the casing under the action of air pressure through the pressure relief section.

[0136] In some embodiments, the housing further includes a first wall and a pressure relief mechanism, the first wall being disposed opposite to the electrode assembly along a first direction; the first wall being fixedly connected to the pressure relief mechanism, the pressure relief mechanism having a first groove and a pressure relief portion located in the area enclosed by the first groove, the bottom of the first groove having a weak portion, the pressure relief portion being connected to the weak portion, at least a portion of the weak portion being configured to be disconnected during pressure relief to open the pressure relief portion.

[0137] By adopting the above technical solution, the pressure relief section can be opened to form an exhaust channel when the pressure value inside the cylindrical battery cell reaches the threshold, thereby facilitating the release of the electrode sheet to the outside of the casing through the exhaust channel formed by the pressure relief section under the action of air pressure.

[0138] In some embodiments, the outer contour of the orthographic projection of the pressure relief portion is circular on a projection plane perpendicular to the first direction.

[0139] This design ensures that the exhaust channel formed by the pressure relief section is roughly circular, while the electrode assembly is roughly cylindrical. This facilitates the release of pressure through the exhaust channel when the electrode plate experiences thermal runaway, thereby helping to improve the directional pressure relief effect of the battery cell.

[0140] Secondly, embodiments of this application provide a battery device, including a cylindrical battery cell.

[0141] The battery device provided in this application adopts the cylindrical battery cells involved in the above embodiments, which enables the battery device to achieve a highly efficient directional pressure relief effect, thereby helping to improve the reliability and performance of the battery device.

[0142] Thirdly, embodiments of this application provide an electrical device, including a cylindrical battery cell or a battery device.

[0143] The electrical device provided in this application, by employing the cylindrical battery cells or battery devices involved in the above embodiments, helps to improve the reliability and performance of the electrical device.

[0144] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0145] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or exemplary technologies will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0146] Figure 1 is a schematic diagram of a vehicle provided in some embodiments of this application;

[0147] Figure 2 is an exploded view of a battery device provided in some embodiments of this application;

[0148] Figure 3 is a schematic diagram of a cylindrical battery cell provided in some embodiments of this application;

[0149] Figure 4 is a cross-sectional view of Figure 3 along AA;

[0150] Figure 5 is a schematic diagram of the electrode assembly of the cylindrical battery cell shown in Figure 3;

[0151] Figure 6 is a three-dimensional structural diagram of the electrode assembly of the cylindrical battery cell provided in Figure 3 before the tab is bent.

[0152] Figure 7 is an enlarged view of point B in Figure 4;

[0153] Figure 8 is an enlarged view of point C in Figure 4;

[0154] Figure 9 is a schematic projection of the pressure relief mechanism and electrode tab of a cylindrical battery cell provided in some embodiments of this application;

[0155] Figure 10 is a schematic diagram showing the unfolded electrode of a cylindrical battery cell provided in some embodiments of this application;

[0156] Figure 11 is an enlarged view of point D in Figure 10;

[0157] Figure 12 is a partially unfolded schematic diagram of the positive electrode sheet of a cylindrical battery cell provided in some embodiments of this application;

[0158] Figure 13 is a partially unfolded schematic diagram of the negative electrode sheet of a cylindrical battery cell provided in some embodiments of this application;

[0159] Figure 14 is an enlarged view of point E in Figure 4;

[0160] Figure 15 is a schematic diagram showing the unfolded electrode of a cylindrical battery cell provided in some other embodiments of this application;

[0161] Figure 16 is an enlarged view of point F in Figure 15;

[0162] Figure 17 is a schematic projection of the pressure relief section and electrode tab of a cylindrical battery cell provided in some other embodiments of this application;

[0163] Figure 18 is an enlarged view of point G in Figure 17;

[0164] Figure 19 is an enlarged view of point H in Figure 15;

[0165] Figure 20 is an enlarged view of point I in Figure 15;

[0166] Figure 21 is a schematic projection of the electrode assembly and current collector of a cylindrical battery cell provided in some embodiments of this application;

[0167] Figure 22 is a schematic projection of the electrode assembly and current collector of a cylindrical battery cell provided in some other embodiments of this application;

[0168] Figure 23 is a schematic projection of the electrode assembly, current collector and electrode terminals of a cylindrical battery cell provided in some embodiments of this application;

[0169] Figure 24 is a schematic projection of the current collector and pressure relief section of a cylindrical battery cell provided in some embodiments of this application;

[0170] Figure 25 is a partial cross-sectional view of a cylindrical battery cell provided in some other embodiments of this application.

[0171] In the figures, the following labels are used: 1000-Battery device; 2000-Controller; 3000-Motor; 100-Cylindrical battery cell; 10-Electrode assembly; 101-Center hole; 102-First cut-off groove; 103-Bottom surface of the first groove; 104-Winding start end; 105-Winding end; 106-Second cut-off groove; 107-Bottom surface of the second groove; 108-First notched groove; 109-Bottom surface of the third groove; 1010-Second notched groove; 1011-Bottom surface of the fourth groove; 1-Electrode sheet; 1a-Positive electrode sheet; 1b-Negative electrode sheet; 11-Electrode sheet body; 11a-First electrode sheet body; 11b-Second electrode sheet body; 11 1-Active material layer; 112-Main body winding section; 112a-First main body winding section; 112b-Second main body winding section; 113-Main body coil section; 12-Electrode tab; 12a-Positive electrode tab; 12b-Negative electrode tab; 121-Electrode tab winding section; 121a-First electrode tab winding section; 121b-Second electrode tab winding section; 1211-Cut piece; 12111-Bent section; 121111-First bent section; 121112-Second bent section; 1212-Transition connection section; 12121-Winding start section; 12122-Winding middle section; 12123-Winding end section; 122-Electrode... Ear loop portion; 13-Insulating layer; 14-Electrode winding portion; 14a-First electrode winding portion; 14b-Second electrode winding portion; 15-Electrode loop portion; 2-Diaphragm; 20-Outer shell; 201-First groove; 202-Roll groove; 21-Shell; 211-Second end wall; 212-Side wall; 2121-Protrusion; 22-End cap; 221-First end wall; 2211-Pressure relief mechanism; 22111-Pressure relief portion; 22112-Weak portion; 2212-First wall; 30-Current collector; 30a-First current collector; 30b-Second current collector; 301-Exhaust vent; 31-Current main Body; 32-Guide portion; 321-First edge; 40-First welding portion; 50-Electrode terminal; 60-Second welding portion; 200-Box body; 210-First part; 220-Second part; P-Main body; M1-First projection endpoint; M2-Second projection endpoint; M3-First arc; M4-Second arc; M5-First transverse region; N1-Third projection endpoint; N2-Fourth projection endpoint; N3-Third arc; N4-Fourth arc; N5-Second transverse region; L-Wound axis; Z-First direction; Y-Radial; E-Circumferential; W-Wound direction; X-Length direction. Detailed Implementation

[0172] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.

[0173] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0174] Unless otherwise specified, all technical features and optional technical features of the embodiments of this application can be combined with each other to form new technical solutions.

[0175] In the description of the embodiments of this application, it should be understood that the terms "length", "width", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0176] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature.

[0177] In the description of the embodiments of this application, "multiple" means two or more, and unless otherwise explicitly specified, "two or more" includes two. Correspondingly, "multiple groups" means two or more groups, including two groups.

[0178] In the description of the embodiments of this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0179] In the description of 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 three possibilities: A exists, A and B exist simultaneously, and B exists. Additionally, in this application, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0180] In the description of the embodiments of this application, unless otherwise expressly specified and limited, the technical terms "proximity" and "adjacent" refer to proximity in location. For example, among three components A1, A2, and B, if the distance between A1 and B is greater than the distance between A2 and B, then A2 is closer to B than A1, meaning A2 is adjacent to B. Alternatively, B can be said to be adjacent to A2; in other words, A2 is adjacent to B. Similarly, when there are multiple components C, namely C1, C2, ... CN, if one component C, such as C2, is closer to component B than the other components C, then B is adjacent to C2; in other words, C2 is adjacent to B.

[0181] Although this application has been described with reference to preferred embodiments, various modifications can be made thereto and components can be replaced with equivalents without departing from the scope of this application. In particular, the technical features mentioned in the various embodiments can be combined in any manner, provided there is no structural conflict. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

[0182] From a market perspective, the application of battery devices is becoming increasingly widespread. Battery devices are not only used in energy storage systems such as hydropower, thermal power, wind power, and solar power plants, but also extensively in electric vehicles such as electric bicycles, electric motorcycles, and electric cars, as well as in military equipment and aerospace. As the application areas of battery devices continue to expand, the market demand is also constantly increasing. Furthermore, the capacity of battery devices is becoming larger, and the performance requirements for battery devices are becoming increasingly stringent.

[0183] In related technologies, battery devices typically include one or more battery cells. During the use of a battery cell, external short circuits, overcharging, punctures, or flat-plate impacts can easily trigger thermal runaway.

[0184] A battery cell is the smallest unit used to store and output electrical energy. Battery cells can be cylindrical, flat, cuboid, or other shapes; those roughly cylindrical are called cylindrical battery cells.

[0185] A cylindrical battery cell mainly consists of a cylindrical outer casing and electrode components located inside the casing. The outer casing may be equipped with a pressure relief mechanism. During the thermal runaway process of a cylindrical battery cell, when the internal pressure reaches a threshold, the pressure relief mechanism opens to form an exhaust channel. The high-temperature and high-pressure flue gas, high-temperature and high-pressure particulate matter, and other high-temperature and high-pressure media inside the cylindrical battery cell will mainly spread towards the pressure relief mechanism of the outer casing and be released outside the casing through the exhaust channel, achieving a directional pressure relief effect.

[0186] The electrode assembly mainly consists of two electrodes with opposite polarities, namely a positive electrode and a negative electrode. The positive and negative electrodes are alternately stacked and wound to form a wound structure. An electrode generally includes an electrode body and a tab.

[0187] In some cases, the tabs are full tabs, and the tab layers have a strong mutual binding effect, meaning the tabs themselves have a significant binding effect. For example, after the electrode sheet is wound to form an electrode assembly, the tabs can be bent to gather and aggregate the ends of the tabs away from the electrode body, forming a relatively dense stacked layer. On the one hand, this reduces the gaps between the tab layers, facilitating welding of the tabs to the current collector. On the other hand, it allows the tabs to provide a strong binding effect on the entire electrode sheet, ensuring the structural integrity of the electrode assembly to a certain extent and contributing to the charge and discharge performance of the electrode assembly.

[0188] The tabs themselves act as a constraint, strongly hindering the release of high-temperature, high-pressure media. This restricts the release of the high-temperature, high-pressure media generated during thermal runaway in a cylindrical battery cell. The release rate is low, making it difficult for the media to spread to the pressure relief mechanism and be released outside the casing in a timely manner. Instead, it accumulates inside the cylindrical battery cell, resulting in low efficiency and poor effectiveness of directional pressure relief through the mechanism. As thermal runaway continues, the internal pressure of the cylindrical battery cell increases continuously, posing a significant risk of explosion and thus reducing its reliability.

[0189] Based on the above considerations, this application provides a cylindrical battery cell, a battery device, and an electrical device. The electrode assembly includes multiple electrode winding portions distributed along the winding direction of the electrode assembly. A first cutting groove is provided between any two adjacent electrode winding portions along the winding direction of the electrode assembly. The first cutting groove penetrates the end face of the electrode away from the electrode body and is wound at least once along the winding direction, so that the multiple electrode winding portions are disconnected through the first cutting groove. Under the action of the first cutting groove that is wound at least once, the mutual binding effect between the multiple electrode winding portions is weakened, and the mutual binding effect between the multiple electrode winding portions with electrode winding portions and the binding effect between the electrode winding portions and the electrode coil portion are also weakened. By providing a pressure relief section at at least one end of the outer casing along a first direction, and configuring the pressure relief section to at least partially open during pressure relief to form an exhaust channel, the binding force between the multiple tab windings is easily broken under air pressure during thermal runaway of the cylindrical battery cell. The mutual binding force between the multiple electrode windings, and the binding force between the electrode windings and the electrode coils, are also easily broken. This allows at least the portion of the electrode facing the pressure relief section to easily loosen under air pressure, and even be released outside the casing through the pressure relief section. This reduces the obstruction of the tabs to the high-temperature, high-pressure medium, facilitating the spread of the high-temperature, high-pressure medium towards the pressure relief section and its release outside the casing through the exhaust channel formed by the opening of the pressure relief section. Thus, the discharge rate and efficiency of the high-temperature, high-pressure medium can be improved, enabling the cylindrical battery cell to achieve efficient directional pressure relief, thereby contributing to improved reliability of the cylindrical battery cell.

[0190] The cylindrical battery cell involved in this application refers to the smallest unit used for storing and outputting electrical energy. The cylindrical battery cell can be a secondary battery or a primary battery. A secondary battery refers to a cylindrical battery cell that can be recharged after discharge to activate the active materials and continue to be used. The cylindrical 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. The cylindrical battery cell can be cylindrical, flat, cuboid, or other shapes.

[0191] The battery device involved in this application embodiment can be a single physical module comprising one or more cylindrical battery cells, used to provide voltage and capacity. When there are multiple cylindrical battery cells, the multiple cylindrical battery cells are connected in series, in parallel, or in a mixed connection via a busbar. A mixed connection refers to multiple cylindrical battery cells being connected in both series and parallel connections.

[0192] In some embodiments, the battery device can be a battery module. When there are multiple cylindrical battery cells, the multiple cylindrical battery cells are arranged and fixed to form a battery module. As an example, multiple cylindrical battery cells can be fixed to form a battery module using cable ties or the like. As an example, multiple cylindrical battery cells can be fixed to form a battery module using end plates, side plates, or the like.

[0193] In some embodiments, the battery device can be a battery pack, which may include a housing and cylindrical battery cells. As an example, the cylindrical battery cells may be directly housed within the housing. As another example, multiple cylindrical battery cells may first be formed into one or more battery modules and then housed within the housing.

[0194] The cylindrical battery cells and battery devices involved in the embodiments of this application can be used in energy storage devices that use cylindrical battery cells or battery devices as energy storage elements.

[0195] The energy storage device involved in this application embodiment can be an energy storage container or an energy storage cabinet. The energy storage device can be used in energy storage power stations, wind power generation systems, solar power generation systems, mobile power systems, or temporary power supply systems, etc. The energy storage device can store electrical energy as needed and output electrical energy when appropriate. For example, the energy storage device can store electrical energy during off-peak hours and provide power to relevant users or electrical devices during peak hours. The energy storage device can include one or more battery clusters, and each battery cluster includes multiple battery devices. Multiple battery devices in a battery cluster can be connected in series through a busbar to increase the voltage of the energy storage device. When the energy storage device includes multiple battery clusters, the multiple battery clusters can be connected in parallel to increase the capacity of the energy storage device.

[0196] In some embodiments, the energy storage device may further include a cabinet in which the battery clusters are housed.

[0197] The cylindrical battery cell and battery device provided in this application embodiment can also be used in electrical devices that use cylindrical battery cells or battery devices as power sources.

[0198] Electrical devices can include, but are not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric vehicles, vehicles, 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. Spacecraft can include airplanes, rockets, space shuttles, and spacecraft. Based on the power source, vehicles can be gasoline-powered vehicles, natural gas-powered vehicles, or new energy vehicles. New energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles. Based on the drive method, vehicles can be front-wheel drive vehicles, rear-wheel drive vehicles, or four-wheel drive vehicles.

[0199] For ease of description, this application uses a vehicle as an example to illustrate the embodiments of the electrical device.

[0200] In some embodiments, please refer to FIG1, which is a schematic diagram of a vehicle provided in some embodiments of this application. A battery device 1000 is disposed inside the vehicle, and the battery device 1000 may be located at the bottom, front, or rear of the vehicle. The battery device 1000 can be used to power the vehicle; for example, the battery device 1000 can serve as the vehicle's operating power source. The vehicle may also include a controller 2000 and a motor 3000. The controller 2000 is used to control the battery device 1000 to supply power to the motor 3000, for example, to meet the power requirements of the vehicle during starting, navigation, and driving.

[0201] In some embodiments, the battery device 1000 can serve not only as the operating power source for the vehicle, but also as the driving power source for the vehicle, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle.

[0202] In some embodiments, please refer to FIG2, which is an exploded view of a battery device 1000 provided in some embodiments of this application. The battery device 1000 may include a housing 200 and cylindrical battery cells 100. The housing 200 is a structure with internal space for accommodating the cylindrical battery cells 100.

[0203] The enclosure 200 can adopt various structures. In some embodiments, the enclosure 200 may include a first portion 210 and a second portion 220, which overlap each other and together define the internal space of the enclosure 200, which is a closed space. Here, "closed" means covered or shut off; it can be sealed or unsealed. That is, the enclosure 200 can be a sealed structure or an unsealed structure.

[0204] In this configuration, both the first part 210 and the second part 220 can be hollow structures with an opening at one end. The open side of the first part 210 covers the open side of the second part 220, so that the first part 210 and the second part 220 together define the internal space of the box 200. Alternatively, referring to Figure 2, the first part 210 can be a hollow structure with an opening at one end, and the second part 220 is a plate-like structure. The second part 220 covers the open side of the first part 210, so that the first part 210 and the second part 220 together define the internal space of the box 200.

[0205] The box 200, which is composed of the first part 210 and the second part 220, can be of various shapes, such as cylinder, cuboid, etc.

[0206] In some embodiments, multiple cylindrical battery cells 100 can be connected in series, parallel, or mixed to form a whole, and then the whole formed by the multiple cylindrical battery cells 100 is directly housed in the internal space of the housing 200. In other embodiments, multiple cylindrical battery cells 100 can also be connected in series, parallel, or mixed to form a battery module, and the battery module is housed in the internal space of the housing 200. In still other embodiments, multiple cylindrical battery cells 100 can also be connected in series, parallel, or mixed to form multiple battery modules, and the multiple battery modules can then be connected in series, parallel, or mixed to form a whole, and housed in the internal space of the housing 200.

[0207] In some embodiments, referring to Figures 1 and 2, the housing 200 of the battery device 1000 can be part of the vehicle's chassis structure. For example, a portion of the housing 200 can be at least a portion of the vehicle's floor, or a portion of the housing 200 can be at least a portion of the vehicle's crossbeams and longitudinal beams.

[0208] In some embodiments, please refer to Figures 3 to 5 together with other accompanying drawings. Figure 3 is a perspective structural diagram of a cylindrical battery cell 100 provided in some embodiments of this application; Figure 4 is a cross-sectional view along line AA of Figure 3; and Figure 5 is a schematic diagram of the electrode assembly 10 of the cylindrical battery cell 100 provided in Figure 3. The cylindrical battery cell 100 provided in the embodiments of this application may include the electrode assembly 10 and the housing 20.

[0209] The electrode assembly 10 is the component in the cylindrical battery cell 100 where the electrochemical reaction occurs. The electrode assembly 10 is mainly formed by alternating layers and winding of positive electrode 1a and negative electrode 1b, with a separator 2 between the positive electrode 1a and the negative electrode 1b. The separator 2 isolates the positive electrode 1a and the negative electrode 1b, thus insulating them.

[0210] In the cylindrical battery cell 100, the number of electrode components 10 can be one or more.

[0211] Among them, the electrode assembly 10 can also be referred to as a bare cell, a wound body, etc.

[0212] In some embodiments, the cylindrical battery cell 100 may further include an electrolyte, which serves to conduct ions between the positive electrode 1a and the negative electrode 1b. The electrolyte involved in these embodiments may be liquid, gel-like, or solid.

[0213] The housing 20 is used to define the internal environment of the cylindrical battery cell 100 and to house the electrode assembly 10 and the electrolyte.

[0214] In some embodiments, please refer to Figures 3 through 5 together with other figures. The housing 20 may include a housing 21 and an end cap 22, which are components for jointly defining the internal environment of the cylindrical battery cell 100. The internal environment defined by the housing 21 and the end cap 22 is used to accommodate the electrode assembly 10 and the electrolyte.

[0215] The outer shell 20 can be cylindrical. Specifically, the outer shell 21 is cylindrical.

[0216] As shown in Figure 5, the housing 21 and the end cap 22 can be independent components. Specifically, the housing 21 has an opening, and the end cap 22 is placed over the opening of the housing 21 to jointly define the internal environment of the cylindrical battery cell 100 and isolate the internal environment of the cylindrical battery cell 100 from the external environment. Alternatively, the housing 21 and the end cap 22 can be an integrated structure. Specifically, the end cap 22 and the housing 21 can form a common connection surface before the electrode assembly 10 is inserted into the housing. After the electrode assembly 10 is inserted into the housing and needs to be encapsulated, the end cap 22 closes the housing 21.

[0217] The outer casing 20 can be either a sealed or unsealed structure. As an example, if the outer casing 20 is a sealed structure, it can protect the electrode assembly 10 and, to some extent, prevent leakage such as electrolyte leakage. As another example, if the outer casing 20 is an unsealed structure, it can still protect the electrode assembly 10, and a sealing bag may be included between the outer casing 20 and the electrode assembly 10. This sealing bag is used to encapsulate the electrode assembly 10 and the electrolyte. Specifically, the sealing bag can be a bag-shaped insulating structure, Mylar membrane, etc.

[0218] As shown in Figures 3 to 5, there can be one end cap 22, which is located at one end of the housing 21. Alternatively, there can be two end caps 22, which are located at opposite ends of the housing 21.

[0219] The shell 21 and end cap 22 can be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc.

[0220] Please refer to Figures 3 through 11, and in conjunction with other accompanying drawings. Figure 6 is a perspective view of the electrode assembly 10 of the cylindrical battery cell 100 shown in Figure 3 before the tab 12 is bent. Figure 7 is an enlarged view of point B in Figure 4, and Figure 8 is an enlarged view of point C in Figure 4. In Figures 4, 7, and 8, the tab coil portion 122 and the plurality of tab winding portions 121 are divided by dashed lines. Figure 9 is a projection schematic diagram of the pressure relief portion 22111 and the tab 12 of the cylindrical battery cell 100 provided in some embodiments of this application. Specifically, it is a schematic diagram of the orthographic projection of the pressure relief portion 22111 and the tab 12 on a projection plane perpendicular to the first direction Z. On the projection plane perpendicular to the first direction Z, the orthographic projection of the tab 12 includes the orthographic projection of the root position of each tab winding portion 121 and the orthographic projection of the tab coil portion 122. The root position of the tab winding portion 121 can be the transition connection portion 1212 of the tab winding portion 121. In Figure 9, the outer contour lines of the pressure relief portion 22111, the first cut-off groove 102, the first notch groove 108, and the second notch groove 1010 are all dashed lines. Figure 10 is a schematic diagram of the unfolded electrode 1 of the cylindrical battery cell 100 provided in some embodiments of this application, and Figure 11 is an enlarged view of point D in Figure 10. In Figures 10 and 11, the tab ring portion 122 and the plurality of tab winding portions 121 are divided by dashed lines. In Figure 11, the transition connection portion 1212 and the cut-off piece 1211 of the tab winding portion 121 are divided by dashed lines. The cylindrical battery cell 100 provided in the embodiments of this application includes a housing 20 and an electrode assembly 10. The outer casing 20 has a pressure relief section 22111 at at least one end along the first direction Z, and the pressure relief section 22111 is configured to at least partially open during pressure relief. At least a portion of the electrode assembly 10 is disposed within the outer casing 20. The electrode assembly 10 has a wound structure and includes two electrodes 1 with opposite polarities. At least one electrode 1 includes an electrode body 11 and an electrode tab 12 arranged along the first direction Z. The electrode body 11 is coated with an active material layer 111, and at least a portion of the electrode tab 12 is not coated with the active material layer 111. On a projection plane perpendicular to the first direction Z, at least a portion of the electrode tab 12 is projected into the orthographic projection of the pressure relief section 22111. The electrode tab 12 includes a plurality of electrode tab winding portions 121 distributed along the winding direction W of the electrode assembly 10. A first cut-off groove 102 is provided between any two adjacent electrode tab winding portions 121 along the winding direction W of the electrode assembly 10. The first cutting groove 102 penetrates the end face of the tab 12 away from the electrode body 11. The first cutting groove 102 is wound at least once along the winding direction W of the electrode assembly 10.

[0221] The pressure relief section 22111 refers to a component on the housing 20 that can be at least partially opened during pressure relief. It is understood that the housing 20 includes a pressure relief mechanism 2211, which includes the pressure relief section 22111, that is, the pressure relief section 22111 is at least a part of the pressure relief mechanism 2211.

[0222] The pressure relief mechanism 2211 is a mechanism that releases the internal pressure of the cylindrical battery cell 100 when the pressure value inside the cylindrical battery cell 100 reaches a threshold. For example, when the cylindrical battery cell 100 is operating normally, the gas pressure inside the cylindrical battery cell 100 is less than the opening pressure value of the pressure relief mechanism 2211, and the pressure relief mechanism 2211 is in the closed state, and the gas inside the cylindrical battery cell 100 is not connected to the external gas. When the cylindrical battery cell 100 experiences thermal runaway under the influence of internal and external factors such as overcharging, over-discharging, overheating, and mechanical impact, a large amount of high-temperature and high-pressure medium is generated inside the cylindrical battery cell 100, causing the internal pressure of the cylindrical battery cell 100 to exceed the opening pressure value of the pressure relief mechanism 2211. The pressure relief mechanism 2211 changes from the closed state to the open state, and the high-temperature and high-pressure medium inside the cylindrical battery cell 100 can be discharged to the outside of the cylindrical battery cell 100 through the pressure relief mechanism 2211.

[0223] When the cylindrical battery cell 100 experiences thermal runaway, at least a portion of the pressure relief section 22111 opens to achieve directional pressure relief.

[0224] For ease of description, the outer casing 20 is defined to have a first end wall 221 at at least one end along the first direction Z, and the first end wall 221 is provided with a pressure relief mechanism 2211. Specifically, as shown in Figures 4 and 7, the first end wall 221 includes a first wall 2212 and the aforementioned pressure relief mechanism 2211, with the pressure relief mechanism 2211 connected to the first wall 2212. The first end wall 221 is the end structure of the outer casing 20 at at least one end along the first direction Z. The first wall 2212 is a solid wall of the outer casing 20 at at least one end along the first direction Z, and is the portion of the first end wall 221 excluding the pressure relief mechanism 2211. The first wall 2212 and the electrode assembly 10 are disposed opposite each other along the first direction Z. The pressure relief mechanism 2211 can be integrally formed on the first wall 2212, as shown in Figures 4 and 7; or, the pressure relief mechanism 2211 can be separately disposed on the first wall 2212.

[0225] The outer casing 20 may be provided with a pressure relief mechanism 2211 on the casing 21. Understandably, the first end wall 221 is a part of the casing 21. The outer casing 20 may also be provided with a pressure relief mechanism 2211 on the end cover 22. Understandably, as shown in Figures 4 and 7, the first end wall 221 is at least a part of the end cover 22.

[0226] The outer casing 20 has a first end wall 221 at one end along the first direction Z, that is, a pressure relief mechanism 2211 is provided at one end along the first direction Z, as shown in Figures 4 and 7. Alternatively, the outer casing 20 has a first end wall 221 at both ends along the first direction Z, that is, a pressure relief mechanism 2211 is provided at both ends along the first direction Z.

[0227] As shown in Figure 5, the electrode assembly 10 includes two electrodes 1 with opposite polarities. Specifically, the electrode assembly 10 includes two electrodes 1 with opposite polarities, and these two electrodes 1 can be a positive electrode 1a and a negative electrode 1b, respectively. The positive electrode 1a can include an electrode body 11 and a tab 12 arranged along a first direction Z. The electrode body 11 of the positive electrode 1a is a first electrode body 11a, and the tab 12 of the positive electrode 1a is a positive electrode tab 12a. Similarly, the negative electrode 1b can also include an electrode body 11 and a tab 12 arranged along the first direction Z. The electrode body 11 of the negative electrode 1b is a second electrode body 11b, and the tab 12 of the negative electrode 1b is a negative electrode tab 12b. Understandably, the aforementioned electrode body 11 can be the electrode body 11 of the positive electrode 1a, which is the first electrode body 11a; or it can be the electrode body 11 of the negative electrode 1b, which is the second electrode body 11b. The aforementioned tab 12 can be the tab 12 of the positive electrode 1a, which is the positive tab 12a; or it can be the tab 12 of the negative electrode 1b, which is the negative tab 12b.

[0228] When both the positive electrode 1a and the negative electrode 1b include an electrode body 11 and a tab 12, the electrode body 11 of the positive electrode 1a, the electrode body 11 of the negative electrode 1b, and the diaphragm 2 can constitute the main body P of the electrode assembly 10. That is, the main body P is mainly composed of the first electrode body 11a, the second electrode body 11b, and the diaphragm 2. The diaphragm 2 is mainly disposed between the electrode body 11 of the positive electrode 1a and the electrode body 11 of the negative electrode 1b. The positive electrode tab 12a and the negative electrode tab 12b can be located together at one end of the main body P along the first direction Z, that is, the electrode assembly 10 has a tab 12 formed at one end along the first direction Z; or, as shown in Figures 4 to 6, the positive electrode tab 12a and the negative electrode tab 12b are respectively disposed at both ends of the main body P along the first direction Z, that is, the electrode assembly 10 has tabs 12 formed at both ends along the first direction Z.

[0229] The electrode body 11 and the electrode tab 12 can be integrally formed, as shown in Figures 5 and 6. Alternatively, the electrode body 11 and the electrode tab 12 can be connected separately.

[0230] Among them, the electrode 12 can be, but is not limited to, a full electrode 12.

[0231] The electrode assembly 10 has a wound structure, meaning that the electrode sheet 1 is wound to form a wound structure. Specifically, both the electrode body 11 and the tab 12 of the electrode sheet 1 are wound, so that both the electrode body 11 and the tab 12 are wound structures. As an example, as shown in Figures 3, 5, and 6, the electrode sheet 1 is wound to form a wound structure, so that the electrode assembly 10 can be approximately cylindrical. Correspondingly, the outer casing 20 is approximately cylindrical, so that the cylindrical battery cell 100 is cylindrical as a whole.

[0232] It should be further noted that the cylindrical battery cell 100 has a winding axis L, which extends along the first direction Z. Furthermore, the electrode 1 is wound around the winding axis L to form a wound structure, thus making the electrode assembly 10, mainly composed of the separator 2 and the two electrode 1 wound together, a wound structure. Specifically, both the electrode body 11 and the tab 12 are arranged around the winding axis L.

[0233] The electrode body 11 may be completely coated with the active material layer 111; or, a portion of the electrode body 11 may be coated with the active material layer 111, while the other portion may not be coated with the active material layer 111. The tab 12 may be completely uncoated with the active material layer 111; or, a portion of the tab 12 may be coated with the active material layer 111, while the other portion may not be coated with the active material layer 111. The active material layer 111 refers to a structural layer composed of active materials.

[0234] For ease of description, the winding direction W of the electrode assembly 10 can be simply referred to as the winding direction W, and the radial direction Y of the electrode assembly 10 can be simply referred to as the radial direction Y, specifically the radial direction of the electrode assembly 10. The winding direction W of the electrode assembly 10 refers to the direction in which the electrode sheet 1 is wound to form the electrode assembly 10, that is, the winding direction W of the tab 12 and the winding direction W of the electrode body 11. It can also be understood as the direction in which the electrode sheet 1 is wound from the winding start end 104 to the winding end end 105 as described below. The first direction Z is approximately the axial direction of the cylindrical battery cell 100, or it can be the width direction of the electrode sheet 1. The first direction Z is approximately perpendicular to the winding direction W of the electrode assembly 10, and the first direction Z is approximately perpendicular to the radial direction Y of the electrode assembly 10. The first direction Z is approximately perpendicular to the length direction X of the electrode sheet 1, that is, the width direction of the electrode sheet 1 and the length direction X of the electrode sheet 1 are approximately perpendicular.

[0235] The first cut-off groove 102 is a groove structure formed between any two adjacent tab winding portions 121 along the winding direction W of the electrode assembly 10. The first cut-off groove 102 penetrates the end face of the tab 12 away from the electrode body 11, and the first cut-off groove 102 does not penetrate the tab 12 along the winding direction W of the electrode assembly 10. Based on this, a plurality of tab winding portions 121 are spaced apart along the winding direction W.

[0236] The first cutting groove 102 is wound at least one turn along the winding direction W of the electrode assembly 10. This means that the first groove bottom surface 103 of the first cutting groove 102 is wound at least one turn along the winding direction W. This can be understood as the first groove bottom surface 103 being wound around the winding axis L at least one turn along the winding direction W. The first groove bottom surface 103 refers to the bottom wall of the first cutting groove 102 along the first direction Z, specifically the wall surface of the first cutting groove 102 on the side closest to the electrode body 11 along the first direction Z. Each first cutting groove 102 has a first groove bottom surface 103. The first cutting groove 102 can be wound one, two, three, four, etc., along the winding direction W, and the number of turns of the first cutting groove 102 does not have to be an integer.

[0237] In some possible designs, as shown in Figures 7, 8, 10, and 11, the tab 12 also includes the tab coil portion 122, which will be discussed below. The tab coil portion 122 is connected between two adjacent tab coil portions 121 along the winding direction W, and the tab coil portion 122 is also disposed between two adjacent tab coil portions 121 along the radial direction Y. The tab coil portion 122 and the two adjacent tab coil portions 121 surround to form a first cut-off groove 102. Based on this, the bottom surface 103 of the first groove is disposed on the edge of the tab coil portion 122 away from the electrode body 11 along the first direction Z. The first cut-off groove 102 is wound at least one turn along the winding direction W, which means that the tab coil portion 122 is wound at least one turn along the winding direction W, and also means that the electrode coil portion 15 discussed below is wound at least one turn along the winding direction W. Alternatively, in some other possible designs, the tab 12 does not include the tab coil portion 122 referred to below, and the bottom surface 103 of the first groove is formed on the side edge of the electrode body 11 along the first direction Z near the tab winding portion 121, such that the bottom surface 103 of the first groove is the boundary between the tab 12 and the electrode body 11, and the first cut-off groove 102 is wound at least once along the winding direction W, which means that the electrode coil portion 15 referred to below is wound at least once along the winding direction W.

[0238] It should be noted that the tab 12 may include multiple tab layers. A tab layer refers to a ring-shaped structure formed by winding the tab 12 one turn, with each tab layer arranged around the outer periphery of the winding axis L. Here, winding the tab 12 one turn means that the tab 12 is wound approximately 360°. All tab layers are sequentially distributed along the radial direction Y of the electrode assembly 10, and all tab layers are also sequentially distributed and connected along the winding direction W of the electrode assembly 10, so that all tab layers form a wound structure, that is, the tab 12 is wound to form a wound structure.

[0239] Accordingly, the electrode body 11 may include multiple electrode layers. An electrode layer refers to a ring-shaped structure formed by winding the electrode body 11 one turn, with each electrode layer arranged around the outer periphery of the winding axis L. Here, winding the electrode body 11 one turn means that the electrode body 11 is wound approximately 360°. All electrode layers are sequentially distributed along the radial direction Y of the electrode assembly 10, and all electrode layers are also sequentially distributed and connected along the winding direction W of the electrode assembly 10, so that all electrode layers form a winding structure, that is, the electrode body 11 is wound to form a winding structure. Among all tab layers and all electrode layers, each tab layer and each electrode layer is correspondingly arranged and connected along the first direction Z, so that the electrode 1 is wound to form multiple ring-shaped structures, thereby forming a winding structure. The ring-shaped structure formed by winding the electrode 1 includes electrode layers and tab layers.

[0240] Multiple electrode loop winding portions 121 are multiple parts formed by dividing the electrode 12 along the winding direction W, and each electrode loop winding portion 121 is a winding structure. Specifically, as shown in FIG9, the multiple electrode loop winding portions 121 of the electrode 12 are distributed sequentially along the winding direction W, and each electrode loop winding portion 121 and each first cut-off groove 102 are alternately arranged along the winding direction W. Each electrode loop winding portion 121 is arranged around the outer periphery of the winding axis L, so that the multiple electrode loop winding portions 121 are also distributed sequentially along the radial direction Y. It can be understood that in all electrode layers of the electrode 12, each electrode loop winding portion 121 is composed of a portion of the electrode layer.

[0241] It should be noted that when the electrode 1 is in the unfolded state, as shown in Figure 10, the multiple electrode winding portions 121 of the electrode tab 12 are sequentially distributed along the length direction X of the electrode 1, and each electrode winding portion 121 and each first cutting groove 102 are alternately arranged along the length direction X of the electrode 1. It can be understood that when the electrode 1 is in the unfolded state, the length direction X of the electrode 1 can be the winding direction W of the electrode assembly 10.

[0242] It should also be noted that the electrode 1 can be divided into an electrode coil portion 15 and multiple electrode winding portions 14 along the winding direction W. The multiple electrode winding portions 14 are distributed sequentially along the winding direction W, and are also distributed sequentially along the radial direction Y. Each electrode winding portion 14 and electrode coil portion 15 is arranged around the outer periphery of the winding axis L. The multiple electrode winding portions 14 and multiple electrode tab winding portions 121 are arranged in a one-to-one correspondence, and each electrode tab winding portion 121 is formed at one end of each electrode winding portion 14 along the first direction Z. The electrode coil portion 15 is connected between two adjacent electrode winding portions 14 along the winding direction W, and is also arranged between two adjacent electrode winding portions 14 along the radial direction Y. The electrode coil portion 15 and the two adjacent electrode tab winding portions 121 enclose a first cut-off groove 102.

[0243] Specifically, each electrode winding portion 14 includes an electrode tab winding portion 121 and a main body winding portion 112. The main body winding portion 112 and the electrode tab winding portion 121 are distributed and connected along the first direction Z to form the electrode winding portion 14. The electrode coil portion 15 includes a main body coil portion 113. The main body coil portion 113 is connected between two adjacent main body winding portions 112 along the winding direction W. The main body coil portion 113 is also disposed between two adjacent main body winding portions 112 along the radial direction Y. It can be understood that both the main body winding portion 112 and the main body coil portion 113 include multiple electrode layers. The electrode layers of the main body winding portion 112 and the electrode tab layers of the electrode tab winding portion 121 are correspondingly disposed and connected along the first direction Z. The electrode layers of the main body winding portion 112 and the corresponding electrode tab layers of the electrode tab winding portion 121 constitute the electrode winding portion 14. When the tab 12 includes the tab coil portion 122 as described below, the electrode coil portion 15 includes the tab coil portion 122. The main coil portion 113 and the tab coil portion 122 are distributed and connected along the first direction Z. The electrode layer of the main coil portion 113 and the tab layer of the corresponding tab coil portion 122 constitute the electrode coil portion 15. When the tab 12 does not include the tab coil portion 122 as described below, the electrode coil portion 15 only includes the main coil portion 113. The electrode layer of the main coil portion 113 constitutes the electrode coil portion 15.

[0244] The number of the electrode loops 121 can be 2, 3, 4, 5, etc.

[0245] By placing at least a portion of the orthographic projection of the tab 12 within the orthographic projection of the pressure relief portion 22111 on a projection plane perpendicular to the first direction Z, it means that at least a portion of the orthographic projection of the tab 12 is located within the area enclosed by the outer contour of the orthographic projection of the pressure relief portion 22111, thereby placing at least a portion of the orthographic projection of the electrode 1 within the orthographic projection of the pressure relief portion 22111.

[0246] On a projection plane perpendicular to the first direction Z, the orthographic projection of the tab 12 refers to the orthographic projection of the root position of the tab 12. The root position of the tab 12 refers to the end region of the tab 12 along the first direction Z near the electrode body 11. For example, the root position of the tab 12 may include the transition connection portion 1212 described below, or it may include the tab coil portion 122 described below.

[0247] On the projection plane perpendicular to the first direction Z, the orthographic projection of electrode 1 refers to the orthographic projection of electrode body 11 of electrode 1.

[0248] The cylindrical battery cell 100 provided in this application embodiment includes a plurality of electrode tab winding portions 121 distributed along the winding direction W of the electrode assembly 10, through the tab 12 of the electrode assembly 10. A first cut-off groove 102 is provided between any two adjacent electrode tab winding portions 121 along the winding direction W of the electrode assembly 10. The first cut-off groove 102 penetrates the end face of the tab 12 away from the electrode body 11 and is wound at least one turn along the winding direction W, so that the plurality of electrode tab winding portions 121 are disconnected through the first cut-off groove 102. Under the action of the first cut-off groove 102 that is wound at least one turn, the mutual binding effect between the plurality of electrode tab winding portions 121 is weakened, and the mutual binding effect between the plurality of electrode winding portions 14 on the electrode 1 with the electrode tab winding portions 121 and the binding effect between the electrode winding portions 14 and the electrode coil portion 15 is also weakened. A pressure relief section 22111 is provided at least at one end of the outer casing 20 along the first direction Z, and the pressure relief section 22111 is configured to open at least partially when pressure is released. This allows the binding effect between the multiple tab winding sections 121 to be easily broken under the action of air pressure during the thermal runaway of the cylindrical battery cell 100. The binding effect between the multiple electrode winding sections 14 and the binding effect between the electrode winding section 14 and the electrode ring section 15 are also easily broken. As a result, at least part of the electrode 1 facing the pressure relief section 22111 can be easily loosened under the action of air pressure, and even released outside the outer casing 20 through the pressure relief section 22111. This can reduce the obstruction effect of the tab 12 on the high temperature and high pressure medium, and facilitate the spread of the high temperature and high pressure medium toward the pressure relief section 22111 and release it outside the outer casing 20 through the pressure relief section 22111. This can improve the discharge rate and efficiency of high-temperature and high-pressure media, enabling the cylindrical battery cell 100 to achieve efficient directional pressure relief, thereby helping to improve the reliability of the cylindrical battery cell 100.

[0249] It should also be noted that by providing a first cutting groove 102, the structural strength of the tab 12 can be reduced. This facilitates the breaking of the mutual binding effect between the multiple tab winding portions 121 under the action of air pressure, so that at least a portion of the electrode 1 can be released outside the outer casing 20 through the pressure relief portion 22111, thereby improving the directional pressure relief efficiency of the cylindrical battery cell 100.

[0250] It should also be noted that the tab 12 is provided with a first cut-off groove 102, which can form a channel for venting, thus facilitating the discharge of high-temperature and high-pressure media and improving the directional pressure relief efficiency of the cylindrical battery cell 100.

[0251] In some embodiments, please refer to Figures 4 to 10 together, and in conjunction with other figures. Among the plurality of tab winding portions 121, they are distributed along the winding direction W of the electrode assembly 10, with the innermost tab winding portion 121 being the first tab winding portion 121a. On a projection plane perpendicular to the first direction Z, at least a portion of the orthographic projection of the first tab winding portion 121a lies within the orthographic projection of the pressure relief portion 22111.

[0252] Understandably, among the plurality of tab winding portions 121, one tab winding portion 121 is a first tab winding portion 121a, and the other tab winding portions 121 surround the outer periphery of the first tab winding portion 121a. Specifically, in the radial direction Y of the electrode assembly 10, the other tab winding portions 121 are located outside the first tab winding portion 121a. In the winding direction W of the electrode assembly 10, the other tab winding portions 121 are located outside the first tab winding portion 121a.

[0253] Correspondingly, the electrode winding portion 14 of the electrode 1 having the first electrode ear winding portion 121a is the first electrode winding portion 14a, and the other electrode winding portions 14 of the electrode 1 surround the outer periphery of the first electrode winding portion 14a.

[0254] On a projection plane perpendicular to the first direction Z, at least a portion of the orthographic projection of the first electrode winding portion 121a is located within the orthographic projection of the pressure relief portion 22111. This means that at least a portion of the orthographic projection of the first electrode winding portion 121a is located within the area enclosed by the outer contour of the orthographic projection of the pressure relief portion 22111, such that at least a portion of the orthographic projection of the first electrode winding portion 14a is located within the orthographic projection of the pressure relief portion 22111.

[0255] On a projection plane perpendicular to the first direction Z, the orthographic projection of the first electrode ear winding portion 121a refers to the orthographic projection of the root position of the first electrode ear winding portion 121a. The root position of the first electrode ear winding portion 121a refers to the end region of the first electrode ear winding portion 121a along the first direction Z near the electrode body 11. For example, the root position of the first electrode ear winding portion 121a includes the transition connection portion 1212 described below.

[0256] On the projection plane perpendicular to the first direction Z, the orthographic projection of the first electrode winding portion 14a refers to the orthographic projection of the electrode body 11 of the first electrode winding portion 14a, which is also the orthographic projection of the main body winding portion 112 of the first electrode winding portion 14a. Among them, the main body winding portion 112 of the first electrode winding portion 14a is the first main body winding portion 112a.

[0257] With this configuration, during the thermal runaway of the cylindrical battery cell 100, the binding effect between the first tab winding portion 121a and other tab winding portions 121 is easily broken under the action of air pressure, thereby making at least a part of the electrode 1 easy to loosen under the action of air pressure, and even release it outside the outer casing 20 through the pressure relief portion 22111. This facilitates the loosening and even release of the electrode 1, which helps the cylindrical battery cell 100 achieve an efficient directional pressure relief effect.

[0258] In some embodiments, please refer to Figures 4 to 10 together, and in conjunction with other figures. On a projection plane perpendicular to the first direction Z, the orthographic projection of the first electrode winding portion 121a is completely located within the orthographic projection of the pressure relief portion 22111.

[0259] On a projection plane perpendicular to the first direction Z, the orthographic projection of the first electrode winding portion 121a is located within the orthographic projection of the pressure relief portion 22111. This means that on a projection plane perpendicular to the first direction Z, the area enclosed by the outer contour of the orthographic projection of the first electrode winding portion 121a is located within the area enclosed by the outer contour of the orthographic projection of the pressure relief portion 22111, thereby making the orthographic projection of the first electrode winding portion 14a located within the area enclosed by the outer contour of the orthographic projection of the pressure relief portion 22111.

[0260] With this configuration, during the depressurization process of the cylindrical battery cell 100, the first electrode winding portion 14a can be loosened by the air pressure, and can even be released outside the outer casing 20 through the exhaust channel formed by the depressurization portion 22111. This helps to improve the directional depressurization effect of the cylindrical battery cell 100.

[0261] In some embodiments, please refer to Figures 4 through 10 together with other figures. The electrode 1 includes a first electrode winding portion 14a, and a first electrode tab winding portion 121a is formed at one end of the first electrode winding portion 14a along a first direction Z. The pressure relief portion 22111 is configured to at least partially open and form an exhaust channel during pressure relief, through which at least a portion of the first electrode winding portion 14a is discharged to the outside of the housing 20.

[0262] Understandably, the electrode winding portion 14 with the first electrode lug winding portion 121a is the first electrode winding portion 14a, the main body winding portion 112 of the first electrode winding portion 14a is the first main body winding portion 112a, and the first electrode lug winding portion 121a is provided at one end of the first main body winding portion 112a along the first direction Z.

[0263] The exhaust channel refers to a channel that penetrates the wall of the outer casing 20 along the first direction Z, through which the pressure relief mechanism 2211 is formed, allowing at least a portion of the first electrode winding portion 14a to be released outside the outer casing 20. When at least a portion of the pressure relief portion 22111 is opened to form the exhaust channel, at least a portion of the first electrode winding portion 14a can be positioned directly opposite the exhaust channel along the first direction Z, so that at least a portion of the first electrode winding portion 14a can be released outside the outer casing 20 under the action of air pressure through the exhaust channel. The wall of the outer casing 20 in which the pressure relief mechanism 2211 is formed can be a first end wall 221, that is, the first end wall 221 includes the pressure relief mechanism 2211.

[0264] By adopting the above technical solution, during the thermal runaway process of the cylindrical battery cell 100, the first electrode winding portion 14a can be released to the outside of the casing 20 through the exhaust channel under the action of air pressure, thus reducing the obstruction effect of the tab 12 on the high-temperature and high-pressure medium. In this process, on the one hand, the high-temperature and high-pressure medium generated inside the cylindrical battery cell 100 can be discharged to the outside of the casing 20 along with the first electrode winding portion 14a; on the other hand, a large channel is formed in the area of ​​the electrode 1 facing the pressure relief portion 22111, and this channel gradually increases in size as the first electrode winding portion 14a is released, facilitating the discharge of the high-temperature and high-pressure medium. This improves the discharge efficiency of the high-temperature and high-pressure medium, enabling the cylindrical battery cell 100 to achieve efficient directional pressure relief, thereby contributing to improved reliability of the cylindrical battery cell 100.

[0265] In some embodiments, please refer to Figures 4 to 10 together with other figures. The number of electrode loop winding portions 121 is at least two. Along the winding direction W, two adjacent electrode loop winding portions 121 can be a first electrode loop winding portion 121a and a second electrode loop winding portion 121b, respectively. Both the first electrode loop winding portion 121a and the second electrode loop winding portion 121b are disposed around the outer periphery of the winding axis L. The second electrode loop winding portion 121b surrounds the outer periphery of the first electrode loop winding portion 121a. Specifically, in the radial direction Y, the second electrode loop winding portion 121b is located outside the first electrode loop winding portion 121a. In the winding direction W, the second electrode loop winding portion 121b is located outside the first electrode loop winding portion 121a. A first cut-off groove 102 is formed between the first electrode loop winding portion 121a and the second electrode loop winding portion 121b.

[0266] Accordingly, there are at least two electrode winding portions 14. Along the winding direction W, two adjacent electrode winding portions 14 can be a first electrode winding portion 14a and a second electrode winding portion 14b, respectively. The second electrode winding portion 14b surrounds the outer periphery of the first electrode winding portion 14a. Specifically, in the radial direction Y, the second electrode winding portion 14b is located outside the first electrode winding portion 14a. In the winding direction W, the second electrode winding portion 14b is located outside the first electrode winding portion 14a. In the winding direction W, an electrode coil portion 15 is connected between the first electrode winding portion 14a and the second electrode winding portion 14b. In the radial direction Y, the electrode coil portion 15 is disposed between the first electrode winding portion 14a and the second electrode winding portion 14b. The first electrode winding portion 14a, the second electrode winding portion 14b, and the electrode coil portion 15 form a first cut-off groove 102. In the first direction Z, the bottom surface 103 of the first cut-off groove 102 is formed on the end face of the electrode ring portion 15 away from the electrode body 11.

[0267] In this configuration, the portion of electrode 1 with the first tab winding portion 121a is called the first electrode winding portion 14a, and the portion of electrode 1 with the second tab winding portion 121b is called the second electrode winding portion 14b. It can be understood that the tab winding portion 121 of the first electrode winding portion 14a is the first tab winding portion 121a, and the main body winding portion 112 of the first electrode winding portion 14a is the first main body winding portion 112a. Similarly, the tab winding portion 121 of the second electrode winding portion 14b is the second tab winding portion 121b, and the main body winding portion 112 of the second electrode winding portion 14b is the second main body winding portion 112b.

[0268] In some embodiments, please refer to Figures 7 and 9 together, and in conjunction with other figures. The tab 12 includes a first cut-off groove 102. On a projection plane perpendicular to the first direction Z, at least a portion of the orthographic projection of the first groove bottom surface 103 of the first cut-off groove 102 lies within the orthographic projection of the pressure relief portion 22111.

[0269] Understandably, there are two pole lug winding portions 121, namely the first pole lug winding portion 121a and the second pole lug winding portion 121b.

[0270] By adopting the above technical solution, on the projection plane perpendicular to the first direction Z, the orthographic projection of the first electrode winding portion 121a and at least a portion of the orthographic projection of the first groove bottom surface 103 of the first cut-off groove 102 are both located within the orthographic projection of the pressure relief portion 22111. Based on this, on the projection plane perpendicular to the first direction Z, the orthographic projection of the first electrode winding portion 14a and at least a portion of the orthographic projection of the electrode ring portion 15 are both located within the orthographic projection of the pressure relief portion 22111.

[0271] In some embodiments, the tab 12 includes a plurality of first cut-off grooves 102. On a projection plane perpendicular to the first direction Z, at least a portion of the orthographic projection of the bottom surface 103 of the first groove of the innermost first cut-off groove 102 lies within the orthographic projection of the pressure relief portion 22111.

[0272] Among them, the innermost first cut-off groove 102 is the first cut-off groove 102 adjacent to the first pole lug winding portion 121a. It can be understood that on the projection plane perpendicular to the first direction Z, the orthographic projection of the first pole lug winding portion 121a and at least part of the orthographic projection of the first groove bottom surface 103 of the adjacent first cut-off groove 102 are both located within the orthographic projection of the pressure relief portion 22111.

[0273] Understandably, on the projection plane perpendicular to the first direction Z, the orthographic projection of the first pole lug winding portion 121a is located within the outer contour of the orthographic projection of the pressure relief portion 22111, and at least a portion of the orthographic projection of the bottom surface 103 of the first groove of the first cut-off groove 102 adjacent to the first pole lug winding portion 121a is also located within the outer contour of the orthographic projection of the pressure relief portion 22111.

[0274] By adopting the above technical solution, the first electrode winding portion 14a can be loosened from the other electrode winding portions 14 when the pressure is released. Thus, during the thermal runaway process of the cylindrical battery cell 100, at least a portion of the first electrode winding portion 14a and the electrode ring portion 15 can be loosened under the action of air pressure, and can even be released to the outside of the outer casing 20 through the exhaust channel formed by the pressure relief portion 22111.

[0275] In this way, the electrode 1 can be loosened under air pressure, and even released through the exhaust channel formed by the pressure relief part 22111. This helps the cylindrical battery cell 100 to achieve efficient directional pressure relief and improves the problem of low directional pressure relief efficiency of the cylindrical battery cell 100.

[0276] In some embodiments, please refer to Figures 4 through 10 together with other figures. At least one electrode 1 has a winding start end 104 and a winding end end 105 at both ends along the winding direction W of the electrode assembly 10.

[0277] A winding start end 104 and a winding end end 105 are respectively disposed at both ends of the electrode 1 along the winding direction W. The winding start end 104 is the end face of one end of the electrode 1 along the winding direction W, and the winding end end 105 is the end face of the other end of the electrode 1 along the winding direction W. In the radial direction Y of the electrode assembly 10, the winding end end 105 is disposed outside the winding start end 104, and the winding start end 104 is closer to the winding axis L than the winding end end 105.

[0278] It should be further noted that, in the radial direction Y of the electrode assembly 10, among the plurality of electrode tab winding portions 121, the innermost electrode tab winding portion 121 has a winding start end 104, and the outermost electrode tab winding portion 121 has a winding end end 105. Correspondingly, in the radial direction Y of the electrode assembly 10, among the plurality of electrode sheet winding portions 14, the winding start end 104 is formed in the innermost electrode sheet winding portion 14, and the winding end end 105 is formed in the outermost electrode sheet winding portion 14.

[0279] It should also be noted that both the positive electrode 1a and the negative electrode 1b can have a winding start end 104 and a winding end end 105.

[0280] As an example, as shown in FIG9, there are two electrode loop winding portions 121. The first electrode loop winding portion 121a has a winding start end 104, and the second electrode loop winding portion 121b has a winding end end 105. Correspondingly, the winding start end 104 is formed in the first electrode winding portion 14a, and the winding end end 105 is formed in the second electrode winding portion 14b.

[0281] In some embodiments, please refer to Figures 4 to 10 together, and in conjunction with other figures. A winding start end 104 is formed in the first electrode winding portion 14a. On a projection plane perpendicular to the first direction Z, the orthographic projection of the winding start end 104 lies within the orthographic projection of the pressure relief portion 22111.

[0282] With this configuration, when the pressure inside the housing 20 reaches a threshold, at least a portion of the first electrode winding portion 14a near the winding start end 104 can be released outside the housing 20 through the exhaust channel. This facilitates the first electrode winding portion 14a to loosen under air pressure and release through the exhaust channel, which helps to improve the directional pressure relief efficiency of the cylindrical battery cell 100.

[0283] In some embodiments, please refer to Figures 4 to 6 and Figure 9 together, and in conjunction with other figures. The tab 12 is provided with a central hole 101 extending along the first direction Z, and each tab winding portion 121 is disposed around the outer periphery of the central hole 101. On a projection plane perpendicular to the first direction Z, the orthographic projection of the central hole 101 is located within the orthographic projection of the pressure relief portion 22111.

[0284] The electrode assembly 10 has a central hole 101 extending along the first direction Z, meaning that the central hole 101 passes through both ends of the electrode assembly 10 along the first direction Z. In the radial direction Y of the electrode assembly 10, the winding start end 104 is closer to the central hole 101 than the winding end end 105.

[0285] Each tab winding portion 121 is arranged around the outer periphery of the central hole 101, meaning that the first tab winding portion 121a and other tab winding portions 121 are arranged around the outer periphery of the central hole 101, such that the first electrode winding portion 14a and other electrode winding portions 14 are arranged around the outer periphery of the central hole 101. As an example, the first tab winding portion 121a and the second tab winding portion 121b are both arranged around the outer periphery of the central hole 101, and correspondingly, the first electrode winding portion 14a and the second electrode winding portion 14b are both arranged around the outer periphery of the central hole 101.

[0286] The first groove bottom surface 103 of the first cut-off groove 102 and the electrode ring portion 15 are both arranged around the outer periphery of the central hole 101.

[0287] Among them, the first electrode winding portion 121a is closer to the center hole 101 than the other electrode winding portions 121. As an example, the first electrode winding portion 121a is closer to the center hole 101 than the second electrode winding portion 121b, and correspondingly, the first electrode winding portion 14a is closer to the center hole 101 than the second electrode winding portion 14b.

[0288] By placing the orthographic projection of the central hole 101 within the orthographic projection of the pressure relief portion 22111 on a projection plane perpendicular to the first direction Z, at least a portion of the first electrode winding portion 14a adjacent to the central hole 101 is positioned directly opposite the pressure relief portion 22111 along the first direction Z. Furthermore, at least a portion of the central hole 101 can be directly opposite to and connected to the exhaust channel formed by the opening of the pressure relief portion 22111 along the first direction Z. Thus, during thermal runaway of the cylindrical battery cell 100, at least a portion of the first electrode winding portion 14a facing the pressure relief portion 22111 can move towards the central hole 101 under air pressure and loosen using the space of the central hole 101. In other words, at least a portion of the electrode 1 adjacent to the central hole 101 can loosen under air pressure. Moreover, as the at least portion of the electrode 1 adjacent to the central hole 101 loosens under air pressure, it can gradually release gas through the exhaust channel formed by the opening of the pressure relief portion 22111 to the outside of the casing 20. Thus, the central hole 101 is designed to facilitate the loosening of the electrode 1 under air pressure and to allow the electrode 1 to be released outside the outer casing 20, thereby facilitating exhaust and achieving a highly efficient directional pressure relief effect.

[0289] It should be further noted that during the process of at least a portion of the electrode 1 adjacent to the central hole 101 being vented to the outside of the housing 20 through the venting channel, at least a portion of the electrode 1 near the winding start end 104 will also be vented to the outside of the housing 20 through the venting channel. This facilitates the loosening of at least a portion of the electrode 1 adjacent to the central hole 101 and allows for venting through the venting channel, thereby improving the directional pressure relief efficiency of the cylindrical battery cell 100.

[0290] During the process of venting pressure through the venting channel formed by the pressure relief section 22111 on electrode 1, the space at the central hole 101 gradually increases as electrode 1 vents pressure. This can be understood as the aperture of the central hole 101 gradually increasing as electrode 1 vents pressure. This facilitates the discharge of high-temperature, high-pressure media through the central hole 101, improving the problem of low exhaust rate caused by an excessively small aperture of the central hole 101, thus achieving a highly efficient directional pressure relief effect.

[0291] In some embodiments, please refer to FIG4, and in conjunction with other figures. The outer diameter of the electrode assembly 10 is D1, and the diameter of the central hole 101 is D2, where D2 / D1 ∈ [5%, 25%].

[0292] Wherein, D2 / D1 can be 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, etc.

[0293] This design allows the central hole 101 to have a large aperture, which facilitates the discharge of the high-temperature and high-pressure medium inside the cylindrical battery cell 100 to the pressure relief section 22111 through the central hole 101 during thermal runaway, thereby achieving a highly efficient directional pressure relief effect.

[0294] In some embodiments, please refer to FIG9, and in conjunction with other figures. The number of turns of the first cut-off groove 102 along the winding direction W of the electrode assembly 10 is ∈ [2, 4].

[0295] Specifically, the number of turns of the first cutting groove 102 along the winding direction W can be 2 turns, 3 turns, 4 turns, or more than 2 turns but less than 3 turns, more than 3 turns but less than 4 turns, etc.

[0296] This configuration helps to reduce the mutual binding effect between the multiple tab winding portions 121, thereby reducing the mutual binding effect between the multiple electrode winding portions 14. This facilitates the breaking of the binding effect between the multiple tab winding portions 121 under pressure during thermal runaway of the cylindrical battery cell 100, and also facilitates the breaking of the mutual binding effect between the multiple electrode winding portions 14 under pressure. This allows at least a portion of the electrode 1 facing the pressure relief portion 22111 to loosen under pressure, and even release pressure through the pressure relief portion 22111 to the outside of the casing 20. This improves the discharge rate and efficiency of the high-temperature, high-pressure medium, enabling the cylindrical battery cell 100 to achieve efficient directional pressure relief, thus contributing to improved reliability of the cylindrical battery cell 100.

[0297] In some embodiments, please refer to Figures 4 to 9 together, and in conjunction with other figures. Each of the two electrode plates 1 includes an electrode plate body 11 and an electrode tab 12, with the electrode tabs 12 of the two electrode plates 1 respectively disposed at both ends of the electrode assembly 10 along the first direction Z. Each electrode tab 12 of each electrode plate 1 includes a plurality of the aforementioned electrode tab winding portions 121.

[0298] Understandably, both electrode tabs 12 of the two electrode plates 1 are provided with the aforementioned first cut-off groove 102.

[0299] Understandably, the two electrodes 1 are a positive electrode 1a and a negative electrode 1b, respectively. Both the positive electrode 1a and the negative electrode 1b include an electrode body 11 and an electrode tab 12. Specifically, the electrode body 11 of the positive electrode 1a is the first electrode body 11a, and the electrode tab 12 of the positive electrode 1a is the positive electrode tab 12a. The electrode body 11 of the negative electrode 1b is the second electrode body 11b, and the electrode tab 12 of the negative electrode 1b is the negative electrode tab 12b. The first electrode body 11a, the second electrode body 11b, and the diaphragm 2 constitute the main body P of the electrode assembly 10. The positive electrode tab 12a and the negative electrode tab 12b are respectively disposed at both ends of the main body P along the first direction Z. On a projection plane perpendicular to the first direction Z, at least a portion of the orthographic projection of the positive electrode tab 12a and at least a portion of the orthographic projection of the negative electrode tab 12b are both located within the orthographic projection of the pressure relief section 22111.

[0300] The positive electrode tab 12a includes a plurality of tab winding portions 121 distributed along the winding direction W, and a first cutting-off groove 102 is provided between any two adjacent tab winding portions 121 along the winding direction W in the positive electrode tab 12a. The negative electrode tab 12b includes a plurality of tab winding portions 121 distributed along the winding direction W, and a first cutting-off groove 102 is provided between any two adjacent tab winding portions 121 along the winding direction W in the negative electrode tab 12b. That is, both the positive electrode tab 12a and the negative electrode tab 12b are provided with the first cutting-off groove 102.

[0301] By adopting the above technical solution, the binding effect between the multiple tab winding portions 121 of the positive electrode tab 12a is weakened, thereby reducing the mutual binding effect between the multiple electrode winding portions 14 of the positive electrode sheet 1a. Furthermore, the binding effect between the multiple tab winding portions 121 of the negative electrode tab 12b is weakened, thereby reducing the mutual binding effect between the multiple electrode winding portions 14 of the negative electrode sheet 1b. In this way, the binding effect of the positive electrode sheet 1a itself, the binding effect of the negative electrode sheet 1b itself, and the mutual binding effect between the positive electrode sheet 1a and the negative electrode sheet 1b can all be reduced. During the thermal runaway of the cylindrical battery cell 100, the binding forces between the multiple tab winding portions 121 of the positive electrode tab 12a and the multiple tab winding portions 121 of the negative electrode tab 12b can be broken under air pressure. This allows at least the portion of the positive electrode 1a facing the pressure relief portion 22111 and at least the portion of the negative electrode 1b facing the pressure relief portion 22111 to loosen under air pressure and release pressure through the exhaust channel formed by the opening of the pressure relief portion 22111 to the outside of the casing 20. This arrangement facilitates the release of pressure through the exhaust channel to the outside of the casing 20 for at least the portion of the electrode assembly 10 facing the pressure relief portion 22111, achieving a highly efficient directional pressure relief effect and thus contributing to the reliability of the cylindrical battery cell 100.

[0302] As an example, as shown in Figure 9, on the projection plane perpendicular to the first direction Z, in the positive electrode tab 12a, the orthographic projection of the first electrode tab winding portion 121a and the orthographic projection of the first groove bottom surface 103 of the adjacent first cut-off groove 102 are both located within the outer contour of the orthographic projection of the pressure relief portion 22111. In the negative electrode tab 12b, the orthographic projection of the first electrode tab winding portion 121a and the orthographic projection of the first groove bottom surface 103 of the adjacent first cut-off groove 102 are both located within the outer contour of the orthographic projection of the pressure relief portion 22111.

[0303] In some embodiments, please refer to Figures 12 and 13 together, and in conjunction with other accompanying drawings. Figure 12 is a partially unfolded schematic diagram of the positive electrode 1a of a cylindrical battery cell 100 provided in some embodiments of this application. In Figure 12, both the insulating layer 13 and the active material layer 111 are shown in cross-section. Figure 13 is a partially unfolded schematic diagram of the negative electrode 1b of a cylindrical battery cell 100 provided in some embodiments of this application. In Figure 13, the active material layer 111 is shown in cross-section. In Figures 12 and 13, the transition connection portion 1212 and the section 1211 are separated by dashed lines. The electrode body 11 includes a current collector and an active material layer 111 coated on the current collector. Specifically, the active material layer 111 is coated on the surface of the current collector along its thickness direction. The current collector is a conductive structure, and the current collector and the tab 12 are electrically connected.

[0304] In the positive electrode 1a, the current collector may be, but is not limited to, aluminum foil. In the negative electrode 1b, the current collector may be, but is not limited to, copper foil.

[0305] In some embodiments, please refer to Figures 12 and 13 together, and in conjunction with other figures. The two electrodes 1 include a positive electrode 1a and a negative electrode 1b.

[0306] In some possible designs, as shown in Figure 12 and in conjunction with other figures, the tab 12 of the positive electrode 1a is not coated with an active material layer 111.

[0307] Understandably, the positive electrode 1a includes a first electrode body 11a and a positive electrode tab 12a. The current collector and the positive electrode tab 12a are electrically connected.

[0308] In this configuration, the first electrode body 11a may be completely coated with the active material layer 111, meaning the current collector is completely coated with the active material layer 111; and the positive electrode tab 12a is completely uncoated with the active material layer 111. Based on this, in the first direction Z, the edge of the active material layer 111 near the positive electrode tab 12a forms the boundary between the first electrode body 11a and the positive electrode tab 12a; that is, in the positive electrode 1a, the portion coated with the active material layer 111 is the first electrode body 11a, and the portion uncoated with the active material layer 111 is the positive electrode tab 12a. Alternatively, the positive electrode tab 12a may be completely uncoated with the active material layer 111, and in the first direction Z, the end region of the first electrode body 11a near the positive electrode tab 12a may not be coated with the active material layer 111, while the remaining portion of the first electrode body 11a may be coated with the active material layer 111; that is, one part of the current collector is coated with the active material layer 111, and the other part is not coated with the active material layer 111.

[0309] In some possible designs, please refer to Figure 13, and in conjunction with other figures. The tab 12 of the negative electrode 1b is not coated with the active material layer 111.

[0310] Understandably, the negative electrode 1b includes a second electrode body 11b and a negative electrode tab 12b. The current collector and the negative electrode tab 12b are electrically connected.

[0311] In this configuration, the second electrode body 11b may be completely coated with the active material layer 111, meaning the current collector is completely coated with the active material layer 111; and the negative electrode tab 12b is completely uncoated with the active material layer 111. Based on this, in the first direction Z, the edge of the active material layer 111 near the negative electrode tab 12b forms the boundary between the second electrode body 11b and the negative electrode tab 12b; that is, in the negative electrode 1b, the portion coated with the active material layer 111 is the second electrode body 11b, and the portion uncoated with the active material layer 111 is the negative electrode tab 12b. Alternatively, the negative electrode tab 12b may be completely uncoated with the active material layer 111, and in the first direction Z, the end region of the second electrode body 11b near the negative electrode tab 12b may not be coated with the active material layer 111, while the remaining portion of the second electrode body 11b is coated with the active material layer 111; that is, one part of the current collector is coated with the active material layer 111, and the other part is not coated with the active material layer 111.

[0312] If at least one of the positive electrode 1a and the negative electrode 1b has a tab 12 without an active material layer 111, then during the process of cutting the tab 12 to form the tab winding portion 121 and the first cutting groove 102, only the tab 12 is cut and not the electrode body 11, so the part of the electrode 1 with the active material layer 111 is not cut. As a result, the first cutting groove 102 is formed in the part of the electrode 1 without the active material layer 111. This can ensure the performance of the active material layer 111 to a certain extent, so as to ensure the performance of the electrode assembly 10 to a certain extent, thereby improving the charge and discharge performance of the cylindrical battery cell 100.

[0313] In some embodiments, please refer to Figures 4 and 14 together, and in conjunction with other figures. Figure 14 is an enlarged view of point E in Figure 4. In Figure 14, the tab 12 and the electrode body 11 are divided by dashed lines. The electrode assembly 10 has a winding axis L parallel to the first direction Z, and at least one tab winding portion 121 has a bent section 12111 in the first direction Z.

[0314] The bent section 12111 is the portion of the tab winding portion 121 that is bent relative to the electrode body 11. Specifically, the bent section 12111 is formed at the end of the tab winding portion 121 that is away from the electrode body 11 along the first direction Z.

[0315] In some possible designs, as shown in Figure 14 and in conjunction with other figures, the bent segment 12111 includes a first bent portion 121111, which is bent relative to the electrode body 11 in a direction close to the winding axis L.

[0316] The first bending portion 121111 refers to the part of the bending section 12111 that is bent relative to the electrode body 11 toward the winding axis L.

[0317] In some possible designs, as shown in Figure 14 and in conjunction with other figures, the bent segment 12111 includes a second bent portion 121112, which is bent relative to the electrode body 11 in a direction away from the winding axis L.

[0318] The second bending section 121112 refers to the part of the bending section 12111 that is bent away from the winding axis L relative to the electrode body 11.

[0319] This configuration allows the end region of the tab winding portion 121 facing away from the electrode body 11 along the first direction Z to be bent, thereby gathering and assembling it to form a relatively dense stacked layer. This reduces the gap between the tab layers of the tab winding portion 121, facilitating welding of the tab winding portion 121 to the current collector 30 described below. Furthermore, the bending of the tab 121 provides a stronger binding effect on the electrode 1, resulting in higher structural integrity and performance of the electrode assembly 10.

[0320] It should be further explained that the first bending portion 121111 is bent in the direction close to the winding axis L, meaning that the first bending portion 121111 is bent in the direction close to the center hole 101. The second bending portion 121112 is bent in the direction away from the winding axis L, meaning that the second bending portion 121112 is bent in the direction away from the center hole 101.

[0321] In some embodiments, please refer to Figures 4 and 14 together, and in conjunction with other figures. Each tab winding portion 121 is provided with a bent section 12111 in the first direction Z.

[0322] This configuration allows for a more comprehensive bending process at the end region of the tab 12 that is away from the electrode body 11 along the first direction Z, thereby forming a relatively dense stacked layer.

[0323] In some embodiments, please refer to Figures 15 to 18 together with other figures. Figure 15 is a schematic diagram showing the unfolded electrode 1 of a cylindrical battery cell 100 according to other embodiments of this application. In Figure 15, the tab coil portion 122 and the plurality of tab winding portions 121 are divided by dashed lines. Figure 16 is an enlarged view of point F in Figure 15. In Figure 16, the transition connection portion 1212 and the section 1211 of the tab winding portion 121 are divided by dashed lines. Figure 17 is a schematic projection diagram of the pressure relief portion 22111 and the tab 12 of a cylindrical battery cell 100 according to other embodiments of this application. Specifically, it is a schematic diagram of the orthographic projection of the pressure relief portion 22111 and the tab 12 on a projection plane perpendicular to the first direction Z. On the projection plane perpendicular to the first direction Z, the orthographic projection of the tab 12 includes the orthographic projection of the root position of the tab winding portion 121 and the orthographic projection of the tab coil portion 122. The orthographic projection of the root position of the tab winding portion 121 can be the orthographic projection of the transition connection portion 1212 of the tab winding portion 121. In Figure 17, the outer contour lines of the pressure relief portion 22111, the first cut-off groove 102, the first notch groove 108, the second notch groove 1010, and the second cut-off groove 106 are all dashed lines. Figure 18 is an enlarged view of point G in Figure 17. In Figure 18, the outer contour lines of the pressure relief portion 22111, the first cut-off groove 102, and the second cut-off groove 106 are all dashed lines. At least one tab winding portion 121 includes a plurality of segments 1211 distributed along the winding direction W of the electrode assembly 10, and in the tab winding portion 121, a second cut-off groove 106 is provided between any two adjacent segments 1211 along the winding direction W of the electrode assembly 10.

[0324] The second cut-off groove 106 is a groove structure formed between any two adjacent segments 1211 along the winding direction W of the electrode assembly 10. The second cut-off groove 106 penetrates the end face of the electrode tab winding portion 121 away from the electrode body 11 along the first direction Z, and the second cut-off groove 106 does not penetrate the electrode tab 12 along the winding direction W of the electrode assembly 10.

[0325] It should be noted that when the electrode 1 is in a wound state to form a wound structure, the multiple segments 1211 of the electrode tab winding portion 121 are sequentially distributed along the winding direction W of the electrode assembly 10, and the segments 1211 and the second cutting grooves 106 are alternately arranged along the winding direction W of the electrode assembly 10. When the electrode 1 is in an unfolded state, as shown in FIG10, the multiple segments 1211 of the electrode tab winding portion 121 are sequentially distributed along the length direction X of the electrode 1, that is, sequentially distributed along the length direction X of the electrode tab 12, and the segments 1211 and the second cutting grooves 106 are alternately distributed along the length direction X of the electrode 1.

[0326] In some embodiments, please refer to Figures 15 to 18 together with other figures. On a projection plane perpendicular to the first direction Z, the orthographic projection of the bottom surface 107 of at least one second cut-off groove 106 is located within the orthographic projection of the pressure relief portion 22111.

[0327] The second groove bottom surface 107 refers to the groove bottom wall of the second cut-off groove 106 along the first direction Z, specifically the wall surface of the second cut-off groove 106 along the first direction Z near the electrode body 11. Each second cut-off groove 106 is provided with a second groove bottom surface 107.

[0328] In some possible designs, as shown in Figures 16 to 18, the tab winding portion 121 further includes a transition connection portion 1212, which is disposed between the piece 1211 and the electrode body 11 along the first direction Z. The second bottom surface 107 of the second cutting groove 106 is formed on the edge of the transition connection portion 1212 away from the electrode body 11 along the first direction Z. Alternatively, in other possible designs, the tab winding portion 1211 does not include the transition connection portion 1212. The piece 1211 contacts the electrode body 11 along the first direction Z, and the second bottom surface 107 of the second cutting groove 106 is formed on the edge of the electrode body 11 near the piece 1211 along the first direction Z, such that the edge of the piece 1211 near the electrode body 11 along the first direction Z forms the boundary between the electrode body 11 and the tab winding portion 121.

[0329] On a projection plane perpendicular to the first direction Z, the orthographic projection of the bottom surface 107 of at least one second cut-off groove 106 lies within the orthographic projection of the pressure relief section 22111. This means that the area enclosed by the outer contour of the orthographic projection of the bottom surface 107 of at least one second cut-off groove 106 lies within the area enclosed by the outer contour of the orthographic projection of the pressure relief section 22111. Specifically, when there is only one second cut-off groove 106, on a projection plane perpendicular to the first direction Z, the orthographic projection of the bottom surface 107 of the second groove lies within the orthographic projection of the pressure relief section 22111. When there are multiple second cut-off grooves 106, on a projection plane perpendicular to the first direction Z, the orthographic projections of the second groove bottom surfaces 107 of all the second cut-off grooves 106 are located within the orthographic projection of the pressure relief portion 22111; or, on a projection plane perpendicular to the first direction Z, the orthographic projections of the second groove bottom surfaces 107 of some of the second cut-off grooves 106 are located within the orthographic projection of the pressure relief portion 22111, and the orthographic projections of at least a portion of the second groove bottom surfaces 107 of some of the second cut-off grooves 106 are located outside the orthographic projection of the pressure relief portion 22111. Based on this, on a projection plane perpendicular to the first direction Z, at least a portion of the orthographic projection of the tab 12 with the second cut-off groove 106 is located within the orthographic projection of the pressure relief portion 22111, and at least a portion of the orthographic projection of the tab winding portion 121 with the second cut-off groove 106 is located within the orthographic projection of the pressure relief portion 22111.

[0330] The at least one tab winding portion 121 includes a plurality of segments 1211 distributed along the winding direction W of the electrode assembly 10. In the tab winding portion 121, a second cutting groove 106 is provided between any two adjacent segments 1211 along the winding direction W of the electrode assembly 10, thereby reducing the density of the deposited layer formed by the portion of the tab winding portion 121 with the second cutting groove 106. Because the orthographic projection of the bottom surface 107 of the second cutting groove 106 of the at least one second cutting groove 106 is located within the orthographic projection of the pressure relief portion 22111 on a projection plane perpendicular to the first direction Z, the self-binding effect of the at least one tab winding portion 121 on the portion of the pressure relief portion 22111 is weakened under the action of the second cutting groove 106, thereby also weakening the self-binding effect of the at least one electrode winding portion 14. During thermal runaway of the cylindrical battery cell 100, at least a portion of the binding force of at least one tab winding portion 121 on the pressure relief portion 22111 can be easily broken under air pressure, allowing at least one electrode winding portion 14 to be easily released outside the casing 20 through the exhaust channel under air pressure. This helps the cylindrical battery cell 100 achieve efficient directional pressure relief, improving the problem of low directional pressure relief efficiency and thus contributing to improved reliability.

[0331] It should also be noted that by forming a second cut-off groove 106 in at least one tab winding portion 121, the connection strength between the tab layers of the at least one tab winding portion 121 itself can be reduced. This facilitates the breaking of at least a portion of the binding effect of the at least one tab winding portion 121 on the pressure relief portion 22111 under the action of air pressure, so that at least one electrode winding portion 14 can be released outside the casing 20 through the pressure relief portion 22111, thereby improving the directional pressure relief efficiency of the cylindrical battery cell 100.

[0332] It should be further noted that at least one tab winding portion 121 of the positive electrode tab 12a may include a plurality of segments 1211 distributed along the winding direction W, and in the positive electrode tab 12a, a second cutting groove 106 is provided between any two adjacent segments 1211 along the winding direction W. In the positive electrode tab 12a, the orthographic projection of the bottom surface 107 of the second groove of at least one second cutting groove 106 is located within the orthographic projection of the pressure relief portion 22111.

[0333] At least one tab winding portion 121 of the negative electrode tab 12b may include a plurality of segments 1211 distributed along the winding direction W, and in the negative electrode tab 12b, a second cutting groove 106 is provided between any two adjacent segments 1211 along the winding direction W. In the negative electrode tab 12b, the orthographic projection of the bottom surface 107 of the second groove of at least one second cutting groove 106 is located within the orthographic projection of the pressure relief portion 22111.

[0334] As an example, as shown in Figures 16 to 18, the first electrode lug winding portion 121a includes multiple segments 1211 as described above, and is provided with the second cutting groove 106 as described above. With this configuration, when the pressure value inside the housing 20 reaches a threshold, the mutual binding effect between the first electrode lug winding portion 121a and other electrode lug winding portions 121, as well as the self-binding effect of the first electrode lug winding portion 121a, is broken under the action of air pressure. This allows the first electrode lug winding portion 14a to be released outside the housing 20 through the pressure relief portion 22111 under the action of air pressure, thereby achieving a highly efficient directional pressure relief effect.

[0335] In some embodiments, please refer to Figures 15 to 18 together with other figures. The plurality of electrode loop winding portions 121 include adjacent first electrode loop winding portions 121a and second electrode loop winding portions 121b, wherein the second electrode loop winding portion 121b is disposed outside the first electrode loop winding portion 121a.

[0336] Understandably, among the plurality of electrode loop winding portions 121, two adjacent electrode loop winding portions 121 are respectively a first electrode loop winding portion 121a and a second electrode loop winding portion 121b. The second electrode loop winding portion 121b surrounds the outer periphery of the first electrode loop winding portion 121a. Specifically, the second electrode loop winding portion 121b is located outside the first electrode loop winding portion 121a along the radial direction Y, and also outside the first electrode loop winding portion 121a along the winding direction W.

[0337] In some embodiments, please refer to Figures 15 to 18 together with other figures. The first electrode winding portion 121a includes a plurality of the aforementioned segments 1211. On a projection plane perpendicular to the first direction Z, in the first electrode winding portion 121a, the orthographic projection of the bottom surface 107 of at least one second cut-off groove 106 is located within the orthographic projection of the pressure relief portion 22111.

[0338] Understandably, the first electrode ear winding portion 121a includes a plurality of the above-mentioned segments 1211 distributed sequentially along the winding direction W, and in the first electrode ear winding portion 121a, a second cutting groove 106 is provided between any two adjacent segments 1211 along the winding direction W.

[0339] By adopting the above technical solution, the self-binding effect of the first electrode winding portion 121a is weakened by the setting of the second cutting groove 106. In this way, when the pressure value inside the outer casing 20 reaches the threshold, the first electrode winding portion 14a can be released to the outside of the outer casing 20 through the pressure relief portion 22111, so that the cylindrical battery cell 100 can achieve a highly efficient directional pressure relief effect.

[0340] It should be further noted that, on the projection plane perpendicular to the first direction Z, when the orthographic projection of the first groove bottom surface 103 of the first pole lug winding portion 121a and its adjacent first cut-off groove 102 is within the outer contour of the orthographic projection of the pressure relief portion 22111, the orthographic projection of the second groove bottom surface 107 of all the second cut-off grooves 106 of the first pole lug winding portion 121a is completely within the outer contour of the orthographic projection of the pressure relief portion 22111.

[0341] In some embodiments, please refer to Figures 15 to 18 together with other figures. The second electrode loop winding portion 121b includes a plurality of the aforementioned segments 1211.

[0342] Understandably, the second electrode ear winding portion 121b includes a plurality of the aforementioned segments 1211 arranged sequentially along the winding direction W, and in the second electrode ear winding portion 121b, a second cutting groove 106 is formed between any two adjacent segments 1211 along the winding direction W.

[0343] A first cutting groove 102 is provided between the segment 1211 of the first pole ear winding portion 121a adjacent to the segment 121b of the second pole ear winding portion 121b and the segment 1211 of the second pole ear winding portion 121b adjacent to the segment 121a of the first pole ear winding portion 121a.

[0344] In the projection plane perpendicular to the first direction Z, the orthographic projection of the bottom surface 107 of the second groove of at least one second cut-off groove 106 of the second pole ear winding portion 121b may or may not be located within the orthographic projection of the pressure relief portion 22111.

[0345] In some embodiments, please refer to Figures 15 to 17 together with other figures. Among the plurality of segments 1211 of the second electrode loop winding portion 121b, the segment 1211 closest to the first electrode loop winding portion 121a is wound at least three times.

[0346] Understandably, in the second electrode ear winding portion 121b, the segment 1211 closest to the first cutting groove 102 between the second cutting groove 106 and the first cutting groove 102 is wound at least three times along the winding direction W.

[0347] Among the multiple electrode pieces 1 of the second electrode ear winding portion 121b, the piece 1211 closest to the first electrode ear winding portion 121a can be wound with 3, 4, 5, 6, 7, 8, 9, etc.

[0348] The number of turns of the cut piece 1211 refers to the number of layers of the tab layer corresponding to the cut piece 1211.

[0349] This configuration allows the segment 1211 closest to the first cut-off groove 102 in the second electrode winding portion 121b to effectively wrap around the first cut-off groove 102, thus improving the problem of electrode 12 collapsing due to the first cut-off groove 102. This enhances the overall binding effect of the electrode 12, resulting in higher performance of the electrode assembly 10.

[0350] In some embodiments, please refer to FIG17 and other accompanying drawings. Among the plurality of segments 1211 of the second electrode ear winding portion 121b, the segment 1211 closest to the first electrode ear winding portion 121a has ≤8 turns.

[0351] Among the multiple segments 1211 of the second pole ear winding portion 121b, the segment 1211 closest to the first pole ear winding portion 121a can have 3, 4, 5, 6, 7, or 8 turns, or more than 3 turns but less than 4 turns, more than 4 turns but less than 5 turns, more than 5 turns but less than 6 turns, more than 6 turns but less than 7 turns, or more than 7 turns but less than 8 turns.

[0352] This configuration allows the segment 1211 closest to the first cut-off groove 102 in the second tab winding portion 121b to effectively wrap around the first cut-off groove 102, thus mitigating the problem of tab 12 collapsing due to the first cut-off groove 102. On the other hand, it also allows the second cut-off groove 106 to be formed in the second tab winding portion 121b, which helps to improve the directional pressure relief efficiency of the cylindrical battery cell 100.

[0353] In some embodiments, please refer to FIG14, and in conjunction with other figures. In the electrode assembly 10, there is a winding axis L parallel to a first direction Z, and at least one segment 1211 is provided with a bent section 12111 in the first direction Z.

[0354] The bent segment 12111 is the part of the cut piece 1211 that is bent relative to the electrode body 11. Specifically, the bent segment 12111 is formed at the end of the cut piece 1211 that is away from the electrode body 11 along the first direction Z.

[0355] In some possible designs, please refer to Figure 14, and in conjunction with other figures. The bent segment 12111 includes a first bent portion 121111, which is bent relative to the electrode body 11 in a direction close to the winding axis L.

[0356] The first bending portion 121111 refers to the part of the bending section 12111 that is bent relative to the electrode body 11 toward the winding axis L.

[0357] In some possible designs, please refer to Figure 14, and in conjunction with other figures. The bent section 12111 includes a second bent portion 121112, which is bent relative to the electrode body 11 in a direction away from the winding axis L.

[0358] The second bending section 121112 refers to the part of the bending section 12111 that is bent away from the winding axis L relative to the electrode body 11.

[0359] This configuration allows the end region of the tab 1211 that is away from the electrode body 11 along the first direction Z to be bent to form a relatively dense stacked layer, thereby forming a stacked layer in the end region of the tab 12 that is away from the electrode body 11 along the first direction Z.

[0360] In some embodiments, please refer to FIG14, and in conjunction with other figures. Each segment 1211 has a bent segment 12111 at one end in the first direction Z.

[0361] In this configuration, each segment 1211 may include a first bending portion 121111 in its bent section, but not a second bending portion 121112, allowing all segments 1211 to be bent toward the winding axis L, thereby enabling a regular bending operation of the second electrode ear winding portion 121b. Alternatively, each segment 1211 may include a second bending portion 121112 in its bent section, but not a first bending portion 121111, allowing the second electrode ear winding portion 121b to be bent. Alternatively, each segment 1211 may include a first bending portion 121111 and a second bending portion 121112, allowing the second electrode ear winding portion 121b to be bent. Alternatively, among the multiple segments 1211, a portion of the segment 12111 has a bent segment 12111 including a first bent portion 121111 or a second bent portion 121112, and another portion of the segment 12111 has a bent segment 121111 including a first bent portion 121111 and a second bent portion 121112. Alternatively, among the multiple segments 1211, a portion of the segment 12111 has a bent segment 12111 including a first bent portion 121111, another portion of the segment 12111 has a bent segment 121111 including a second bent portion 121112, and the remaining portion of the segment 12111 has a bent segment 121111 including a first bent portion 121111 and a second bent portion 121112.

[0362] This configuration allows each segment 1121 of the tab 12 to be bent, enabling the end region of the tab 12 away from the electrode body 11 along the first direction Z to be bent, thereby gathering and assembling to form a relatively dense stacked layer.

[0363] In some embodiments, please refer to FIG14, and in conjunction with other figures. The first bend 121111 is provided with a radial Y bend along the electrode assembly 10.

[0364] Specifically, in the radial direction Y of the electrode assembly 10, the first bent portion 121111 is bent toward the direction close to the winding axis L.

[0365] In some embodiments, as shown in FIG14 and in conjunction with other figures, the second bending portion 121112 is provided with a radial Y-bend along the electrode assembly 10.

[0366] Specifically, in the radial direction Y of the electrode assembly 10, the second bent portion 121112 is bent in a direction away from the winding axis L.

[0367] By adopting the above technical solution, the bending section 12111 is bent radially Y, which enables the tab 12 to be bent effectively to form a deposited layer.

[0368] In some other embodiments, the first bending portion 121111 may be bent in a direction intersecting the radial Y, and the second bending portion 121112 may also be bent in a direction intersecting the radial Y.

[0369] In some embodiments, please refer to FIG14, and in conjunction with other figures. The bent segment 12111 includes at least one first bent portion 121111 and at least one second bent portion 121112, the first bent portion 121111 and the second bent portion 121112 being alternately arranged along a first direction Z.

[0370] This configuration allows the end region of the tab 12 that is away from the electrode body 11 along the first direction Z to be bent, thereby gathering and assembling to form a relatively dense stacked layer.

[0371] In some embodiments, please refer to FIG12 and other figures. The two electrodes 1 include a positive electrode 1a and a negative electrode 1b. The tab 12 of the positive electrode 1a is not coated with an active material layer 111, and / or the tab 12 of the negative electrode 1b is not coated with an active material layer 111. In the first direction Z, an insulating layer 13 is provided at the end region of the tab 12 near the electrode body 11, and a cut-off piece 1211 is located on the side of the insulating layer 13 facing away from the electrode body 11.

[0372] Among them, insulating layer 13 refers to a structural layer with insulating properties, and insulating layer 13 can be an insulating coating, insulating adhesive, etc.

[0373] Specifically, in the first direction Z, at least a portion of the insulating layer 13 is provided on the end region of the tab winding portion 121 near the electrode body 11. The tab winding portion 121 may be entirely provided with the insulating layer 13; alternatively, the end region of the tab winding portion 121 away from the electrode body 11 along the first direction Z may not have the insulating layer 13 provided.

[0374] Specifically, when the tab 12 includes the tab coil portion 122 mentioned in the previous section, a portion of the insulating layer 13 may be provided on the end region of the tab coil portion 122 along the first direction Z close to the electrode body 11. The tab coil portion 122 may be entirely provided with the insulating layer 13; alternatively, the end region of the tab coil portion 122 along the first direction Z away from the electrode body 11 may not have the insulating layer 13 provided.

[0375] As shown in Figure 12, the insulating layer 13 may be disposed only on the end region of the tab winding portion 121 near the electrode body 11, and not on the first electrode body 11a. Therefore, the edge of the insulating layer 13 along the first direction Z near the first electrode body 11a forms the boundary between the positive electrode tab 12a and the first electrode body 11a. Alternatively, a portion of the insulating layer 13 may be disposed on the end region of the first electrode body 11a along the first direction Z near the positive electrode tab 12a. When the end region of the first electrode body 11a near the positive electrode tab 12a is not coated with the active material layer 111, the portion of the first electrode body 11a without the active material layer 111 must be provided with the insulating layer 13.

[0376] In some possible designs, as shown in Figure 12, in the first direction Z, the segments 1211 of the positive electrode tab 12a are spaced apart on the side of the insulating layer 13 facing away from the first electrode body 11a. Based on this, the second groove bottom surface 107 of the second cutting groove 106 is spaced apart on the side of the insulating layer 13 facing away from the first electrode body 11a along the first direction Z. Alternatively, in other possible designs, in the first direction Z, the segments 1211 of the positive electrode tab 12a are located on the side of the insulating layer 13 facing away from the first electrode body 11a. Furthermore, the second groove bottom surface 107 of the second cutting groove 106 coincides with the edge of the insulating layer 13 facing away from the first electrode body 11a along the first direction Z.

[0377] This configuration provides an insulating layer 13 on the positive electrode 1a, which effectively improves the short circuit problem between the positive electrode 1a and the negative electrode 1b.

[0378] In some embodiments, please refer to Figures 15 and 16 together, and in conjunction with other figures. At least one tab winding portion 121 includes a transition connection portion 1212 and the aforementioned segment 1211, with the electrode body 11, the transition connection portion 1212, and the segment 1211 arranged sequentially along a first direction Z. In the tab winding portion 121, the transition connection portion 1212 and any two segments 1211 adjacent to each other along the winding direction W of the electrode assembly 10 form a second cut-off groove 106. The second groove bottom surface 107 of the second cut-off groove 106 is formed on one side edge of the transition connection portion 1212 for connecting the segment 1211.

[0379] Understandably, the electrode winding portion 121 includes a transition connection portion 1212 and a plurality of segments 1211, which are spaced apart along the winding direction W on the transition connection portion 1212. The electrode body 11 is connected to one side of the transition connection portion 1212 along the first direction Z, and the segments 1211 are connected to the other side of the transition connection portion 1212 along the first direction Z. Specifically, the current collector is connected to the side of the transition connection portion 1212 away from the segments 1211 along the first direction Z.

[0380] Understandably, the second groove bottom surface 107 of the second cut-off groove 106 is formed on the side edge of the transition connection portion 1212 along the first direction Z close to the cut piece 1211, specifically the second groove bottom surface 107 is the end face of the electrode ring portion 15 away from the electrode body 11.

[0381] A transition connection portion 1212 connects the electrode body 11 and the cut piece 1211. On one hand, the electrode body 11 and the cut piece 1211 are spaced apart along the first direction Z, and the electrode body 11 and the second cutting groove 106 are also spaced apart along the first direction Z. This makes it easier to avoid the electrode body 11 during the process of cutting the electrode lug winding portion 121 to form the second cutting groove 106 and the cut piece 1211, thus preventing the electrode body 11 from being cut to a certain extent. Furthermore, it solves the problem that the electrode body 11 is easily torn because the second groove bottom surface 107 of the second cutting groove 106 is formed on one side edge of the electrode body 11. On the other hand, the transition connection portion 1212 can block the cut piece 1211, thereby isolating the cut piece 1211 from the main body portion P of the electrode assembly 10. This improves the problem of short circuits in the electrode assembly 10 caused by the cut piece 1211 being bent and inserted into the main body portion P, reducing the risk of short circuits.

[0382] It should be noted that, referring to Figure 12 and other accompanying figures, in the positive electrode 1a, an insulating layer 13 is disposed on at least a portion of the transition connection portion 1212. In some possible designs, as shown in Figure 12, the insulating layer 13 is disposed on a portion of the transition connection portion 1212 such that the insulating layer 13 and the segment 1211 are spaced apart along the first direction Z. Alternatively, in other possible designs, the insulating layer 13 completely covers the transition connection portion 1212, such that the edge of the insulating layer 13 facing away from the electrode body 11 along the first direction Z coincides with the edge of the segment 1211 close to the transition connection portion 1212 along the first direction Z.

[0383] In some embodiments, please refer to Figures 12, 13, 15, 16, 19, and 20 together, and in conjunction with other figures. Figure 19 is an enlarged view of point H in Figure 15, and Figure 20 is an enlarged view of point I in Figure 15. In Figures 19 and 20, the transition connection 1212 and the piece 1211 are divided by dashed lines. The dimension of one side edge of the piece 1211 used to connect the transition connection 1212 in the winding direction W of the electrode assembly 10 is H1, and the dimensions of the transition connection 1212 and the piece 1211 in the first direction Z are H2, where 0.01 ≤ H2 / H1 ≤ 0.3.

[0384] The section 1211, used to connect one side edge of the transition connection portion 1212, refers to the side edge of the section 1211 along the first direction Z that is closer to the electrode body 11, i.e., the edge of the section 1211 at the boundary between the section 1211 and the transition connection portion 1212. The boundary between the section 1211 and the transition connection portion 1212 is mainly based on the position of the bottom surface 103 of the first groove, which can be specifically referred to in Figures 12, 13, 16, 19, and 20 for dividing the transition connection portion 1212 and the section 1211. It can be understood that the side edge of the section 1211 used to connect the transition connection portion 1212 is collinearly connected with the bottom surface 107 of the second groove.

[0385] The dimension of the side edge of the piece 1211 used to connect the transition connection portion 1212 in the winding direction W of the electrode assembly 10 refers to the maximum dimension of the piece 1211 in the winding direction W. It also refers to the dimension of the side edge of the piece 1211 used to connect the transition connection portion 1212 in the length direction X of the electrode 1 when the electrode 1 is in the unfolded state. In other words, the maximum dimension of the piece 1211 in the length direction X of the electrode 1 when the electrode 1 is in the unfolded state.

[0386] The sum of the dimensions of the transition connection 1212 and the segment 1211 in the first direction Z refers to the maximum dimension of the tab 12 in the first direction Z when the tab 1 is in the first direction Z before it is turned on or in the unfolded state.

[0387] 0.01≤H2 / H1≤0.3, where H2 / H1 can be 0.01, 0.05, 0.1, 0.15, 0.2, 0.25, 0.3, etc.

[0388] This configuration allows the cut piece 1211 to have a larger size in the winding direction W, which facilitates the winding of the cut piece 1211 and, to a certain extent, ensures the structural integrity of the electrode assembly 10 and, to a certain extent, the charging and discharging performance of the cylindrical battery cell 100.

[0389] In some embodiments, please refer to FIG16 and other figures. The dimension of the transition connection portion 1212 in the first direction Z is H3, 0.1mm≤H3≤2mm.

[0390] The dimension of the transition connection portion 1212 in the first direction Z refers to the distance between the edge of the piece 1211 near the electrode body 11 and the edge of the electrode body 11 near the piece 1211 in the first direction Z.

[0391] H3 can be 0.1mm, 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, 1.6mm, 1.7mm, 1.8mm, 1.9mm, 2mm, etc.

[0392] With this configuration, the second cut-off groove 106 can be formed in the tab winding portion 121, and the transition connection portion 1212 has a suitable width in the first direction Z to block the cut piece 1211, which can improve the problem of the cut piece 1211 bending and inserting into the main body portion P.

[0393] In some embodiments, please refer to FIG17 and other figures. Among the plurality of tab winding portions 121, along the winding direction W of the electrode assembly 10, the outermost tab winding portion 121 includes a plurality of the aforementioned segments 1211, and the segment 1211 closest to the winding end 105 is wound at least one turn.

[0394] Understandably, among the multiple segments 1211 of the outermost tab winding portion 121, the segment 1211 closest to the winding end 105 is wound at least once in the winding direction W.

[0395] Among them, the segment 1211 closest to the winding end 105 is the segment 1211 farthest from the winding axis L.

[0396] In the radial direction Y of the electrode assembly 10, the outermost electrode lug winding portion 121 may be, but is not limited to, the second electrode lug winding portion 121b.

[0397] The number of turns of the cut piece 1211 refers to the number of layers of the tab layer of the cut piece 1211.

[0398] As an example, as shown in Figure 16, among the multiple segments 1211 of the second pole ear winding portion 121b, the segment 1211 closest to the winding end 105 is wound multiple times.

[0399] By winding the piece 1211 closest to the winding end 105 at least once, the piece 1211 closest to the winding end 105 can achieve a better wrapping effect on the other pieces 1211. This can improve the problem of internal short circuit caused by the piece 1211 turning outward and inserting into the main body P, thereby reducing the risk of short circuit.

[0400] In some embodiments, please refer to FIG15, and in conjunction with other figures. At least one tab winding portion 121 is provided with a plurality of second cut-off grooves 106, and in the tab winding portion 121, each second cut-off groove 106 and each cut piece 1211 are alternately arranged along the winding direction W of the electrode assembly 10.

[0401] Understandably, the number of segments 1211 in the tab winding portion 121 is at least three, so that the number of second cut-off grooves 106 in the tab winding portion 121 is at least two.

[0402] Understandably, multiple second cut-off grooves 106 are spaced apart on the tab winding portion 121 along the winding direction W, and multiple segments 1211 are sequentially arranged on the tab winding portion 121 along the winding direction W, with each second cut-off groove 106 and each segment 1211 arranged alternately along the winding direction W.

[0403] By forming multiple second cut-off grooves 106 on the tab winding portion 121, the tab winding portion 121 can achieve a larger removal ratio, allowing the portion of the electrode winding portion 14 with the second cut-off grooves 106 to be released through the pressure relief portion 22111 during thermal runaway, thus achieving a highly efficient directional pressure relief effect. Furthermore, the deposited layer formed by bending the portion of the tab winding portion 121 with the second cut-off grooves 106 is not too thin, effectively blocking the laser generated during welding, thereby achieving a protective effect on the diaphragm 2. In addition, the multiple second cut-off grooves 106 allow the tab 12 removal operation to be adjusted according to actual needs, making the operation of removing the tab 12 to form the second cut-off grooves 106 highly flexible.

[0404] In some embodiments, as shown in FIG15 and in conjunction with other figures, the dimensions of each of the plurality of second cut-off slots 106 in the tab winding portion 121 may be the same. For example, the dimensions of each of the second cut-off slots 106 along the winding direction W may be the same. Alternatively, at least two of the plurality of second cut-off slots 106 in the tab winding portion 121 may have different dimensions.

[0405] In some embodiments, as shown in FIG15 and in conjunction with other figures, the shapes of each of the plurality of second cut-off grooves 106 in the tab winding portion 121 may be identical. Alternatively, at least two of the plurality of second cut-off grooves 106 in the tab winding portion 121 may have different shapes.

[0406] In some embodiments, as shown in FIG. 15 and in conjunction with other figures, at least two of the plurality of segments 1211 of the tab winding portion 121 may have different dimensions. For example, as shown in FIG. 15, the two segments 1211 may have different dimensions along the winding direction W. Alternatively, the tabs 12 of the plurality of segments 1211 of the tab winding portion 121 may have the same size.

[0407] As shown in FIG15, among the multiple segments 1211 of the electrode loop winding portion 121, each segment 1211 may have the same shape. Alternatively, at least two segments 1211 of the multiple segments 1211 of the electrode loop winding portion 121 may have different shapes.

[0408] In some embodiments, please refer to Figures 15 and 16, and in conjunction with other figures. In the first direction Z, the size of the slit 1211 along the winding direction W of the electrode assembly 10 tends to decrease in the direction away from the electrode body 11.

[0409] In the first direction Z, the segment 1211 can be gradually tapered away from the electrode body 11 on one side of the winding direction W of the electrode assembly 10; or, in the first direction Z, the segment 1211 can be gradually tapered away from the electrode body 11 on both sides of the winding direction W of the electrode assembly 10, so that when the electrode 1 is in the unfolded state, the segment 1211 is approximately trapezoidal. Based on this, in the first direction Z, the size of the segment 1211 gradually decreases in the direction away from the electrode body 11 along the winding direction W.

[0410] Accordingly, in the first direction Z, the second cutting groove 106 is gradually widened along one or both sides of the winding direction W in a direction away from the electrode body 11, so that in the first direction Z, the size of the second cutting groove 106 along the winding direction W gradually increases in a direction away from the electrode body 11.

[0411] Accordingly, in the first direction Z, the first cutting groove 102 is gradually widened along one or both sides of the winding direction W in a direction away from the electrode body 11, so that in the first direction Z, the size of the first cutting groove 102 along the winding direction W gradually increases in a direction away from the electrode body 11.

[0412] By gradually decreasing the size of the truncated piece 1211 in the first direction Z along the winding direction W away from the electrode body 11, the binding effect of the accumulated layer formed by bending at the end region of the truncated piece 1211 away from the electrode body 11 is reduced. This helps the portion of the electrode 1 with the second cut-off groove 106 to loosen during thermal runaway and release pressure through the venting channel formed by the pressure relief section 2211. Furthermore, the arrangement of the first cut-off groove 102 facilitates the easy loosening of at least one electrode winding portion 14 from other electrode winding portions 14 under pressure, and even allows for pressure release through the pressure relief section 22111. Based on this, the directional pressure relief efficiency is improved.

[0413] In some embodiments, please refer to Figures 7 to 9, 15, 17, 19, and 20 together, and in conjunction with other figures. Among the plurality of tab winding portions 121, the innermost tab winding portion 121 along the winding direction W of the electrode assembly 10 is provided with a first notch 108. The first notch 108 penetrates the winding start end 104 along the winding direction W of the electrode assembly 10, and penetrates the end face of the tab winding portion 121 opposite to the electrode body 11. On a projection plane perpendicular to the first direction Z, the orthographic projection of the bottom surface 109 of the third groove of the first notch 108 lies within the orthographic projection of the pressure relief portion 22111.

[0414] Among them, the innermost electrode lug winding portion 121 is the electrode lug winding portion 121 closest to the winding start end 104, which can be the aforementioned first electrode lug winding portion 121a. That is, the first electrode lug winding portion 121a has the winding start end 104 and is provided with a first notch groove 108. Correspondingly, the electrode sheet winding portion 14 with the winding start end 104 and the first notch groove 108 can be the first electrode sheet winding portion 14a.

[0415] The third groove bottom surface 109 of the first notch groove 108 refers to the groove bottom wall of the first notch groove 108 along the first direction Z, specifically the wall surface of the first notch groove 108 along the first direction Z near the electrode body 11.

[0416] By placing the orthographic projection of the bottom surface 109 of the third groove of the first notch 108 within the orthographic projection of the pressure relief portion 22111 on a projection plane perpendicular to the first direction Z, the electrode winding portion 14 (which may be the first electrode winding portion 14a) with the first notch 108 is also positioned directly opposite the pressure relief portion 22111 along the first direction Z. This reduces the binding effect of the electrode winding portion 14 with the first notch 108, facilitating the release of pressure from the electrode winding portion 14 with the first notch 108 to the outside of the casing 20 via the pressure relief portion 22111 during thermal runaway, thereby improving the directional pressure relief efficiency of the cylindrical battery cell 100.

[0417] In some embodiments, please refer to Figures 7 through 9 together with other figures. The cylindrical battery cell 100 also includes a current collector 30, at least a portion of which is disposed within the housing 20.

[0418] In some embodiments, please refer to Figures 7 to 9, 17 and 19 together, and in conjunction with other figures. In the first direction Z, the tab winding portion 121 has a winding start section 12121 located at one end of the first notch 108 near the electrode body 11, and the bottom surface 109 of the third groove of the first notch 108 is the end face of the winding start section 12121 facing away from the electrode body 11. The current collector 30 is welded to the portion of the tab winding portion 121 that extends beyond the bottom surface 109 of the third groove in the direction away from the electrode body 11, and is not welded to the winding start section 12121.

[0419] The bottom surface 109 of the third groove is formed on the side edge of the winding starting section 12121 away from the electrode body 11 along the first direction Z.

[0420] When the electrode lug winding portion 121 closest to the winding start end 104 forms a slit 1211 and a second cutting groove 106, in the first direction Z, the slit 1211 extends beyond the bottom surface 109 of the third groove of the first notch groove 108 in a direction away from the electrode body 11, specifically extending beyond the winding start section 12121. The winding start section 12121 and the adjacent slit 1211 together form the first notch groove 108.

[0421] Wherein, when the tab winding portion 121 closest to the winding start end 104 includes a transition connection portion 1212, the winding start segment 12121 is a part of the transition connection portion 1212 of the tab winding portion 121. It can be understood that the transition connection portion 1212 of the tab winding portion 121 closest to the winding start end 104 may include a winding intermediate segment 12122 and a winding start segment 12121. The winding start segment 12121 and the winding intermediate segment 12122 are connected sequentially along the winding direction W of the electrode assembly 10. The winding intermediate segment 12122 and the winding start segment 12121 are both provided on the side edge of the electrode body 11 along the first direction Z near the tab 12, and the winding intermediate segment 12122 is connected between the electrode body 11 and the cut piece 1211 along the first direction Z. When the electrode winding portion 121 closest to the winding start end 104 does not include the transition connection portion 1212, the stub 1211 and the winding start segment 12121 are both provided on the side edge of the electrode body 11 along the first direction Z close to the electrode 12. The winding start segment 12121 and the stub 1211 are distributed sequentially along the winding direction W of the electrode assembly 10, and the size of the stub 1211 along the first direction Z is larger than the size of the winding start segment 12121 along the first direction Z.

[0422] The current collector 30 is welded to the portion of the tab winding portion 121 that extends beyond the bottom surface 109 of the third groove, specifically, the current collector 30 is welded to the segment 1211 of the tab winding portion 121 closest to the winding start end 104.

[0423] By placing the orthographic projection of the bottom surface 109 of the third groove within the orthographic projection of the pressure relief portion 22111 on a projection plane perpendicular to the first direction Z, the winding starting segment 12121 and the pressure relief portion 22111 are positioned opposite each other along the first direction Z. As an example, as shown in Figures 9, 17, and 18, on a projection plane perpendicular to the first direction Z, the orthographic projection of the winding starting segment 12121 is located within the outer contour of the orthographic projection of the pressure relief portion 22111.

[0424] The current collector 30 is welded to the portion of the electrode winding portion 121 that extends beyond the bottom surface 109 of the third groove, and is not welded to the winding start section 12121. This results in a lower binding effect on the portion of the electrode winding portion 14 with the first notch 108. This facilitates the release of pressure through the pressure relief portion 22111 during the thermal runaway of the cylindrical battery cell 100, thereby improving the directional pressure relief efficiency of the cylindrical battery cell 100.

[0425] In some embodiments, please refer to Figures 7 to 9, 15, 17, 19, and 20 together, and in conjunction with other figures. Among the plurality of tab winding portions 121, the outermost tab winding portion 121 along the winding direction W of the electrode assembly 10 is provided with a second notch 1010. The second notch 1010 extends through the winding end 105 along the winding direction W of the electrode assembly 10, and extends through the end face of the tab 12 away from the electrode body 11.

[0426] The outermost tab winding portion 121 is the tab winding portion 121 closest to the winding end 105, and can be the aforementioned second tab winding portion 121b. That is, the second tab winding portion 121b has a winding end 105 and is provided with a second notch 1010. Correspondingly, the electrode winding portion 14 with the winding end 105 and the second notch 1010 can be the second electrode winding portion 14b.

[0427] This configuration allows the second notch 1010 to form a channel for venting. Furthermore, the binding effect of the electrode winding portion 14 with the second notch 1010 is reduced, making it easier for the electrode winding portion 14 with the second notch 1010 to loosen or even eject from the pressure relief portion 22111 during thermal runaway. This, in turn, facilitates improved directional pressure relief efficiency of the cylindrical battery cell 100.

[0428] In some embodiments, please refer to Figures 7 to 9, 17 and 20 together, and in conjunction with other figures. The tab winding portion 121 has a winding end section 12123 located at one end of the second notch 1010 near the electrode body 11, and the fourth groove bottom surface 1011 of the second notch 1010 is the end face of the winding end section 12123 facing away from the electrode body 11. The current collector 30 is welded to the portion of the tab winding portion 121 extending beyond the fourth groove bottom surface 1011 in the direction away from the current collector 11, and is not welded to the winding end section 12123.

[0429] When the electrode lug winding portion 121 closest to the winding end 105 forms a slit 1211 and a second cutting groove 106, in the first direction Z, the slit 1211 extends beyond the bottom surface 1011 of the fourth groove of the second notch groove 1010 in a direction away from the electrode body 11, specifically extending beyond the winding end segment 12123. The winding end segment 12123 and the adjacent slit 1211 together form the second notch groove 1010.

[0430] The bottom surface 1011 of the fourth groove is formed on the edge of the winding end section 12123 along the first direction Z away from the electrode body 11.

[0431] Wherein, when the tab winding portion 121 closest to the winding end 105 includes a transition connection portion 1212, the winding end segment 12123 is a part of the transition connection portion 1212 of the tab winding portion 121. It can be understood that the transition connection portion 1212 of the tab winding portion 121 closest to the winding end 105 may include a winding middle segment 12122 and a winding end segment 12123. The winding end segment 12123 and the winding middle segment 12122 are connected sequentially along the winding direction W of the electrode assembly 10. The winding middle segment 12122 and the winding end segment 12123 are both provided on the side edge of the electrode body 11 along the first direction Z near the tab 12, and the winding middle segment 12122 is connected between the electrode body 11 and the cut-off piece 1211 along the first direction Z. Specifically, in the winding direction W, the winding middle section 12122 of each pole lug winding portion 121 is located between the winding start section 12121 and the winding end section 12123.

[0432] When the tab winding portion 121 closest to the winding end 105 does not include the transition connection portion 1212, the stub 1211 and the winding end segment 12123 are both disposed on the edge of the electrode body 11 along the first direction Z near the tab 12. The winding end segment 12123 and the stub 1211 are sequentially distributed along the winding direction W of the electrode assembly 10, and the size of the stub 1211 along the first direction Z is larger than the size of the winding end segment 12123 along the first direction Z. Specifically, in the winding direction W, all stubs 1211 are disposed between the winding start segment 12121 and the winding end segment 12123.

[0433] The current collector 30 is welded to the portion of the tab winding portion 121 that extends beyond the bottom surface 1011 of the fourth groove, specifically, the current collector 30 is welded to the segment 1211 of the tab winding portion 121 that is closest to the winding end 105.

[0434] The current collector 30 is welded to the portion of the electrode winding portion 121 that extends beyond the bottom surface 1011 of the fourth groove, and is not welded to the winding end section 12123. This results in a lower binding effect on the portion of the electrode winding portion 14 with the second notch 1010. This facilitates the release of pressure through the pressure relief portion 22111 during the thermal runaway of the cylindrical battery cell 100, thereby improving the directional pressure relief efficiency of the cylindrical battery cell 100.

[0435] In some embodiments, please refer to Figures 4, 7 through 9, and other accompanying drawings. The housing 20 also includes a first end wall 221, which is disposed opposite to the electrode assembly 10 along a first direction Z. The first end wall 221 has a first groove 201 and the aforementioned pressure relief portion 22111, the pressure relief portion 22111 being located within the area enclosed by the first groove 201. A weak portion 22112 is provided at the bottom of the first groove 201, and the pressure relief portion 22111 is connected to the weak portion 22112. At least a portion of the weak portion 22112 is configured to disconnect during pressure relief to open the pressure relief portion 22111.

[0436] Understandably, the first end wall 221 includes a first wall 2212, a pressure relief portion 22111, and a weak portion 22112, which together constitute a pressure relief mechanism 2211. Specifically, the weak portion 22112 surrounds the outer periphery of the pressure relief portion 22111, the first wall 2212 surrounds the outer periphery of the pressure relief portion 22111, and the weak portion 22112 connects the pressure relief portion 22111 and the first wall 2212. The weak portion 22112, the pressure relief portion 22111, and the first wall 2212 are integrally formed and enclose the aforementioned first groove 201. Based on this, the first groove 201 makes the thickness of the weak portion 22112 less than the thickness of the first wall 2212, thereby making the structural strength of the weak portion 22112 lower than that of the first wall 2212. Understandably, the first end wall 221 of the outer casing 20 has an integrally formed weak portion 22112 and pressure relief portion 22111 of the pressure relief mechanism 2211.

[0437] The weak point 22112 refers to the part of the outer casing 20 with relatively weak structural strength, which is a part of the pressure relief mechanism 2211. The structural strength of the weak point 22112 is lower than that of other parts of the outer casing 20. As an example, as shown in Figure 6, a groove can be provided on the first end wall 221, forming a first groove 201. This groove is specifically located between the pressure relief part 22111 and the first wall 2212, for example, a groove can be provided on the end cap 22 of the outer casing 20.

[0438] The pressure relief section 22111 refers to the portion of the outer casing 20 that can be opened to form an exhaust passage, and is a part of the pressure relief mechanism 2211. Specifically, when the pressure value inside the outer casing 20 reaches a threshold, at least a portion of the weak section 22112 will break under the action of air pressure, thereby breaking the connection between the pressure relief section 22111 and the first wall 2212, thereby causing at least a portion of the pressure relief section 22111 to open and form an exhaust passage.

[0439] By adopting the above technical solution, the pressure relief section 22111 can be opened to form an exhaust channel when the pressure value inside the cylindrical battery cell 100 reaches the threshold, thereby facilitating the discharge of the electrode 1 to the outside of the casing 20 through the exhaust channel formed by at least the partial opening of the pressure relief section 22111 during thermal runaway.

[0440] In other embodiments, the housing 20 further includes a first wall 2212 and a pressure relief mechanism 2211, the first wall 2212 and the electrode assembly 10 being disposed opposite each other along a first direction Z. The first wall 2212 is fixedly connected to the pressure relief mechanism 2211, the pressure relief mechanism 2211 having a first groove 201 and a pressure relief portion 22111, the pressure relief portion 22111 being located within the area enclosed by the first groove 201. A weak portion 22112 is provided at the bottom of the first groove 201, and the pressure relief portion 22111 is connected to the weak portion 22112. At least a portion of the weak portion 22112 is configured to be disconnectable during pressure relief to open the pressure relief portion 22111.

[0441] Understandably, the pressure relief mechanism 2211 includes a pressure relief portion 22111 and a weak portion 22112. Specifically, the weak portion 22112 surrounds the outer periphery of the pressure relief portion 22111, the first wall 2212 surrounds the outer periphery of the pressure relief portion 22111, the weak portion 22112 is connected to the outer periphery of the pressure relief portion 22111, and the weak portion 22112 and the pressure relief portion 22111 together form the aforementioned first groove 201. Based on this, the provision of the first groove 201 makes the thickness of the weak portion 22112 less than the thickness of other parts of the pressure relief mechanism 22111, thereby making the structural strength of the weak portion 22112 lower than that of other parts of the pressure relief mechanism 22111.

[0442] The pressure relief mechanism 2211 is fixedly connected to the first wall 2212. This connection can be made by the weakest part 22112 of the pressure relief mechanism 2211 to the first wall 2212, or by other parts of the pressure relief mechanism 2211 to the first wall 2212.

[0443] The pressure relief mechanism 2211 can be fixedly connected to the first wall 2212 by welding or other means, so that the pressure relief mechanism 2211 and the first wall 2212 are separately set.

[0444] The pressure relief mechanism 2211 and the first wall 2212 can constitute the aforementioned first end wall 221.

[0445] The weak point 22112 refers to the part of the pressure relief mechanism 2211 where the structural strength is relatively weak, and is a part of the pressure relief mechanism 2211. Specifically, the structural strength of the weak point 22112 is lower than that of other parts of the pressure relief mechanism 2211. As an example, the pressure relief mechanism 2211 may have a groove formed by the groove, which is a first groove 201, specifically surrounding the outer periphery of the pressure relief part 22111.

[0446] When the pressure inside the outer casing 20 reaches the threshold, the weak part 22112 will break under the action of air pressure, thereby breaking the connection between the pressure relief part 22111 and the first wall 2212, so that the pressure relief part 22111 opens to form an exhaust channel.

[0447] By adopting the above technical solution, the pressure relief section 22111 can be opened to form an exhaust channel when the pressure value inside the cylindrical battery cell 100 reaches the threshold, thereby facilitating the electrode 1 to be released to the outside of the outer casing 20 through the exhaust channel formed by the pressure relief section 22111 under the action of air pressure.

[0448] When the aforementioned weak part 22112 is directly connected to the first wall 2212, on the projection plane perpendicular to the first direction Z, the outer contour of the orthographic projection of the pressure relief mechanism 2211 is the outer contour of the orthographic projection of the first groove 201, which is also the outer contour of the orthographic projection of the weak part 22112.

[0449] In some embodiments, please refer to Figures 4, 6, 7, and 15 together, and in conjunction with other figures. On a projection plane perpendicular to the first direction Z, the outer contour of the orthographic projection of the pressure relief portion 22111 is circular.

[0450] This configuration ensures that the exhaust channel formed by the pressure relief section 22111 is roughly circular, while the electrode assembly 10 is roughly cylindrical. This facilitates the release of pressure through the exhaust channel when the electrode 1 experiences thermal runaway, thereby helping to improve the directional pressure relief effect of the cylindrical battery cell 100.

[0451] In some embodiments, please refer to Figures 7 to 11, Figures 15 to 18, and other figures. The tab 12 also includes a tab loop portion 122, which is connected between two adjacent tab winding portions 121 along the winding direction W of the electrode assembly 10, and the tab loop portion 122 and the two adjacent tab winding portions 121 along the winding direction W of the electrode assembly 10 form a first cut-off groove 102.

[0452] Understandably, the tab coil portion 122 and the tab winding portion 121 are multiple parts of the tab 12, with the tab coil portion 122 arranged around the outer periphery of the winding axis L. Specifically, the tab coil portion 122 surrounds and connects to two adjacent tab winding portions 121. In the radial direction Y, the tab coil portion 122 is located between two adjacent tab winding portions 121; in the winding direction W, the tab coil portion 122 is located between and connects to two adjacent tab winding portions 121. Understandably, of all the tab layers of the tab 12, a portion of the tab layers are wound to form the tab winding portion 121, and another portion of the tab layers are wound to form the tab coil portion 122.

[0453] Correspondingly, the portion of the electrode 1 with the tab 122 is the electrode coil portion 15. The electrode coil portion 15 surrounds and connects to two adjacent electrode winding portions 14. Specifically, in the radial direction Y, the electrode coil portion 15 is located between two adjacent electrode winding portions 14; in the winding direction W, the electrode coil portion 15 is located between two adjacent electrode winding portions 14 and connects to two adjacent electrode winding portions 14. The electrode coil portion 15 includes the aforementioned main coil portion 113 and tab 122 arranged along the first direction Z. The main coil portion 113 surrounds and connects to two adjacent main coil portions 112. It can be understood that in all electrode layers of the electrode body 11, a portion of the electrode layers are wound to form the electrode winding portion 14, and another portion of the electrode layers are wound to form the electrode coil portion 15.

[0454] Understandably, in the first direction Z, the tab winding portion 121 extends beyond the tab coil portion 122, so that the tab coil portion 122 can be formed with the two adjacent tab winding portions 14 to form a first cut-off groove 102.

[0455] The first groove bottom surface 103 of the first cut-off groove 102 is formed on the side edge of the electrode loop portion 122 away from the electrode body 11 along the first direction Z.

[0456] The number of turns of the first cut-off groove 102 is the same as the number of turns of the tab coil portion 122, and also the number of tab layers of the tab coil portion 122.

[0457] When the electrode winding portion 121 forms the aforementioned transition connection portion 1212, the electrode loop portion 122 is connected between two adjacent transition connection portions 1212 along the winding direction W. Specifically, the electrode loop portion 122 is connected between the winding middle sections 12122 of two adjacent transition connection portions 1212 along the winding direction W.

[0458] In the first direction Z, the bottom surface 103 of the first groove may extend beyond the bottom surface 107 of the second groove in a direction away from the electrode body 11. Alternatively, in the first direction Z, the bottom surface 107 of the second groove may also extend beyond the bottom surface 103 of the first groove in a direction away from the electrode body 11. Alternatively, in the first direction Z, the bottom surfaces 103 of the first groove and 107 of the second groove are flush.

[0459] In the positive electrode 1a, the tab portion 122 may be completely provided with the insulating layer 13; or, the tab portion 122 may only be provided with the insulating layer 13 in a portion thereof.

[0460] This configuration allows the tab coil portion 122 to block the tab winding portion 121, which can improve the problem of internal short circuit caused by the tab winding portion 121 bending and inserting into the main body portion P, thereby reducing the risk of short circuit.

[0461] In some embodiments, please refer to Figures 11 and 16 together, and in conjunction with other figures. The dimension of the tab portion 122 in the first direction Z is H4, 0.1mm≤H4≤2mm.

[0462] H4 can be 0.1mm, 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, 1.6mm, 1.7mm, 1.8mm, 1.9mm, 2mm, etc.

[0463] This configuration allows the tab coil portion 122 to have a certain size in the first direction Z. Based on the fact that the tab 12 can form the first cut-off groove 102, the tab coil portion 122 can block the tab winding portion 121, thereby improving the problem of the tab winding portion 121 bending and inserting into the main body portion P.

[0464] In some embodiments, please refer to Figures 7 and 8, Figures 21 and 22, and other accompanying drawings. Figure 21 is a projected schematic diagram of the electrode assembly 10 and current collector 30 of a cylindrical battery cell 100 according to some embodiments of this application. Specifically, it is a schematic diagram of the orthographic projection of the electrode assembly 10 and the current collector 30 on a projection plane perpendicular to the first direction Z. In Figure 21, the area shown by the cross-sectional line is the first transverse region M5, and the first arc M3 and the second arc M4 are both dashed lines. Figure 22 is a projected schematic diagram of the electrode assembly 10 and current collector 30 of a cylindrical battery cell 100 according to other embodiments of this application. Specifically, it is a schematic diagram of the orthographic projection of the electrode assembly 10 and the current collector 30 on a projection plane perpendicular to the first direction Z. In Figure 22, the structure shown by the cross-sectional line is the second welded portion 60, and the first arc M3 and the second arc M4 are both dashed lines. The cylindrical battery cell 100 also includes a current collector 30, at least a portion of which is disposed within the housing 20. The current collector 30 is welded to the tab winding portion 121 to form a first weld portion 40. The current collector 30 is not welded to the tab coil portion 122.

[0465] The current collector 30 is a component with conductive properties, mainly used for welding to the tab 12 to achieve current collection for the electrode assembly 10. Specifically, the current collector 30 can be a transition structure between the current transmission end of the cylindrical battery cell 100 and the electrode assembly 10. Specifically, the current collector 30 is welded to the tab 12 to achieve electrical connection between the current collector 30 and the electrode assembly 10. The current collector 30 can also be electrically connected to the current transmission end, thereby achieving electrical connection between the current transmission end and the electrode assembly 10.

[0466] Among them, the current collection component 30 may be, but is not limited to, a current collection disk.

[0467] The current transmission terminal of the cylindrical battery cell 100 refers to the component used to transmit the current of the cylindrical battery cell 100, specifically for outputting or inputting current. The current transmission terminal may include the electrode terminals 50 described below, or it may include the housing 20. The current transmission terminal includes a positive current transmission terminal and a negative current transmission terminal.

[0468] The current collector 30 is welded to the tab 12, specifically to the tab winding portion 121 of the tab 12, that is, the current collector 30 is welded to the tab layer of the tab winding portion 121. The welding of the current collector 30 to the tab winding portion 121 allows the tab winding portion 121 to achieve a certain self-binding effect through welding, thereby providing a strong binding effect on the electrode sheet 1 as a whole, ensuring the structural integrity of the electrode assembly 10 to a certain extent, and facilitating the charging and discharging performance of the electrode assembly 10. When the tab winding portion 121 includes the aforementioned segment 1211, the current collector 30 is welded to the tab winding portion 121, specifically to the segment 1211 of the tab winding portion 121.

[0469] Correspondingly, the current collector 30 is not welded to the tab portion 122, so the current collector 30 basically does not restrain the tab portion 122, thus the self-restraint of the tab portion 122 is weak, and the self-restraint of the electrode ring portion 15 is also weakened. The tab portion 122 and the current collector 30 can be spaced apart along the first direction Z, as shown in Figures 4, 7, and 8; or, the tab portion 122 can be in contact with the current collector 30.

[0470] Specifically, the current collector 30 and the tab 12 are arranged generally along the first direction Z. That is, a current collector 30 is provided between at least one wall of the housing 20 along the first direction Z and the electrode assembly 10. As an example, as shown in FIG4, tabs 12 are formed at both ends of the electrode assembly 10 along the first direction Z, and current collector 30 is provided at both ends of the electrode assembly 10 along the first direction Z. The current collector 30 at each end is welded to the tab winding portion 121 of the tab 12 at each end. As another example, a current collector 30 is provided at one end of the electrode assembly 10 along the first direction Z. It can be understood that the current collector 30 and the tab 12 can be strictly distributed along the first direction Z, and at least a portion of the tab 12 can also be inserted into the current collector 30.

[0471] As shown in Figure 4, the electrode assembly 10 has tabs 12 at both ends along the first direction Z, and a current collector 30 at both ends along the first direction Z. The current collector 30 at each end is welded to the tab winding portion 121 of the tab 12 at each end. Alternatively, the electrode assembly 10 has a current collector 30 at one end along the first direction Z.

[0472] The first welded part 40 refers to the weld mark formed by welding the current collector 30 and the electrode ear winding part 121.

[0473] As an example, as shown in Figure 21, on a projection plane perpendicular to the first direction Z, the orthographic projection of the first weld portion 40 is approximately circular and is arranged around the outer periphery of the central hole 101. As another example, as shown in Figure 22, there are multiple first weld portions 40. On a projection plane perpendicular to the first direction Z, the orthographic projections of multiple first weld portions 40 are spaced apart along the circumferential direction E, and the orthographic projections of multiple first weld portions 40 together are arranged around the outer periphery of the central hole 101.

[0474] The current collector 30 can be welded to the first electrode lug winding portion 121a to form a first welded portion 40; the current collector 30 can also be welded to the second electrode lug winding portion 121b to form the first welded portion 40. As an example, as shown in Figures 4, 7, and 8, in the positive electrode lug 12a, the first welded portion 40 is provided on the second electrode lug winding portion 121b. In the negative electrode lug 12b, the first welded portion 40 is provided on the first electrode lug winding portion 121a.

[0475] The current collector 30 is welded to the tab winding portion 121 of the tab 12, but not to the tab coil portion 122 of the tab 12. This weakens the self-binding effect of the tab coil portion 122, and consequently reduces the self-binding effect of the electrode coil portion 15. This reduces the mutual binding effect between adjacent tab winding portions 121 and adjacent electrode winding portions 14. When the pressure inside the casing 20 reaches a threshold, the electrode 1 can easily loosen under pressure and even release pressure through the pressure relief portion 22111 to the outside of the casing 20, contributing to a highly efficient directional pressure relief effect for the cylindrical battery cell 100.

[0476] Furthermore, by welding the current collector 30 to the tab winding portion 121 but not to the tab ring portion 122, the first solder mark and the first cut-off groove 102 are arranged at radial Y intervals, which facilitates a stable welding of the current collector 30 and the tab 12.

[0477] It should be noted that the circumferential direction E refers to the circumferential direction, and the circumferential direction E is approximately perpendicular to the first direction Z.

[0478] In some embodiments, please refer to Figures 7, 8, 21 to 22, and other figures. On a projection plane perpendicular to the first direction Z, the two ends of the orthographic projection of the first welding portion 40 have a first projection endpoint M1 and a second projection endpoint M2, respectively. The first projection endpoint M1 is closer to the winding axis L parallel to the first direction Z than the second projection endpoint M2. The area between the first arc line M3, which passes through the first projection endpoint M1 and surrounds the winding axis L, and the second arc line M4, which passes through the second projection endpoint M2 and surrounds the winding axis L, is the first transverse region M5. At least one tab winding portion 121 includes a plurality of segments 1211 distributed along the winding direction W of the electrode assembly 10, and in the tab winding portion 121, a second cutting groove 106 is provided between any two adjacent segments 1211 along the winding direction W of the electrode assembly 10. At least a portion of the second cut-off grooves 106 form a first group of grooves, in which the orthographic projection of the bottom surface 107 of all the second cut-off grooves 106 lies within the first transverse region M5. The current collecting member 30 is welded to the cut piece 1211 to form the aforementioned first welded portion 40.

[0479] Understandably, on the projection plane perpendicular to the first direction Z, the first projection endpoint M1 and the second projection endpoint M2 are respectively located at the two ends of the radial Y of the orthographic projection of the first welding part 40. The first arc M3 passes through the first projection endpoint M1, and the second arc M4 passes through the second projection endpoint M2. Both the first arc M3 and the second arc M4 are arranged around the outer periphery of the coiling axis L. The first arc M3 and the second arc M4 are spaced apart along the radial Y, and the second arc M4 surrounds the outer periphery of the first arc M3, so that the first arc M3 and the second arc M4 alternately form a first transverse region M5, which is approximately annular. The first arc M3 and the second arc M4 are both arranged around the outer periphery of the central hole 101.

[0480] When there are multiple first welding parts 40, on the projection plane perpendicular to the first direction Z, each of the multiple first welding parts 40 has a first projection endpoint M1 and a second projection endpoint M2, and the first arc M3 passes through multiple first projection endpoints M1, and the second arc M4 passes through multiple second projection endpoints M2.

[0481] In this configuration, both the first arc M3 and the second arc M4 are arc-shaped. As an example, as shown in Figures 21 and 22, both the first arc M3 and the second arc M4 are circular.

[0482] In the first group of slots, the orthographic projection of the bottom surface 107 of the second slot of all the second cut-off slots 106 is located within the first transverse region M5. Specifically, on the projection plane perpendicular to the first direction Z, the orthographic projection of the bottom surface 107 of each second cut-off slot 106 is substantially located within the first transverse region M5. In other words, all the second cut-off slots 106 whose orthographic projections of the bottom surface 107 are substantially located within the first transverse region M5 on the projection plane perpendicular to the first direction Z constitute the first group of slots. It can be understood that the portion of the tab winding portion 121 where the first welding portion 40 is formed is provided with the aforementioned second cut-off slot 106.

[0483] It should be further explained that, on the projection plane perpendicular to the first direction Z, when the orthographic projection of a portion of the second groove bottom surface 107 of a certain second cut-off groove 106 is located within the first transverse region M5, the second groove bottom surface 107 of the second cut-off groove 106 can be defined as being basically located within the first transverse region M5, and the second cut-off groove 106 is defined as one of the second cut-off grooves 106 in the first group of grooves.

[0484] When the first welding portion 40 is formed on the first electrode ear winding portion 121a, the first set of grooves is provided on the first electrode ear winding portion 121a. Alternatively, when the first welding portion 40 is formed on the second electrode ear winding portion 121b, the first set of grooves is provided on the second electrode ear winding portion 121b. When both the first electrode ear winding portion 121a and the second electrode ear winding portion 121b have the first welding portion 40 formed, the first set of grooves can be provided on the first electrode ear winding portion 121a; or on the second electrode ear winding portion 121b; or a portion of the grooves can be provided on the first electrode ear winding portion 121a and the other portion on the second electrode ear winding portion 121b.

[0485] In some possible designs, please refer to Figures 17 and 18 together, and in conjunction with other accompanying figures. In the first set of slots, the number of turns of a single second cut-off slot 106 is ≤3.

[0486] The number of turns of a single second cut-off groove 106 refers to the number of layers of the tab layer of a single second cut-off groove 106; it can also refer to the number of turns of the second groove bottom surface 107 of a single second cut-off groove 106 along the winding direction W.

[0487] Specifically, the number of turns of a single second cut-off groove 106 can be 1 turn, 2 turns, 3 turns, or less than 1 turn, more than 1 turn and less than 2 turns, more than 2 turns and less than 3 turns, etc.

[0488] As an example, as shown in Figure 18, the second cut-off groove 106 shown in Figure 18 has less than one turn.

[0489] In some possible designs, please refer to Figures 17 and 18 together, and in conjunction with other figures. In the first set of slots, the number of second cut-off slots 106 that are radially opposite and connected along the Y direction of the electrode assembly 10 is ≤3.

[0490] Understandably, on the projection plane perpendicular to the first direction Z, the number of consecutive, opposite, and connected second cut-off slots 106 along the radial direction Y is ≤3. On the projection plane perpendicular to the first direction Z, the number of consecutive, opposite, and connected second cut-off slots 106 along the radial direction Y can be 3 or 2; or, any two second cut-off slots 106 are not opposite and connected along the radial direction Y.

[0491] As an example, as shown in Figure 18, the number of second cut-off slots 106 that are radially opposite and connected along the Y direction can be two.

[0492] By adopting the above technical solution, based on the provision of the second cutting groove 106 in the portion of the electrode winding portion 121 where the first welding portion 40 is formed, the stacked layer formed by bending in the portion of the electrode winding portion 121 where the first welding portion 40 is formed will not be too thin due to the setting of the second cutting groove 106. This allows the portion of the electrode winding portion 121 where the first welding portion 40 is formed to bear the welding penetration of the current collector 30 and the electrode 12, which can improve the problem of laser penetration of the electrode 12 and burning of the diaphragm 2 during the welding process of the current collector 30 and the electrode 12. This can improve the problem of short circuit of the electrode assembly 10 caused by the welding of the current collector 30 and the electrode 12, and reduce the risk of short circuit.

[0493] In some embodiments, please refer to Figures 4, 8, and 23 together, and in conjunction with other accompanying drawings. Figure 23 is a projected schematic diagram of the electrode assembly 10, current collector 30, and electrode terminal 50 of a cylindrical battery cell 100 provided in some embodiments of this application. Specifically, it is a schematic diagram of the orthographic projection of the electrode assembly 10, the current collector 30, and the electrode terminal 50 on a projection plane perpendicular to the first direction Z. In Figure 23, the regions shown by the cross-sectional lines are the first transverse region M5 and the second transverse region N5, respectively. The first arc line M3, the second arc line M4, the third arc line N3, and the third arc line N3 are all dashed lines. The cylindrical battery cell 100 also includes electrode terminals 50, which are fixed to the housing 20. The electrode terminals 50 are welded to the current collector 30 to form a second welded portion 60.

[0494] Electrode terminal 50 refers to a component with conductive properties. Electrode terminal 50 serves as the current transmission terminal of the cylindrical battery cell 100 and is used to transmit current. Electrode terminal 50 may be, but is not limited to, a pole.

[0495] The electrode terminal 50 can be welded to the current collector 30 welded to the positive electrode tab 12a, or it can be welded to the current collector 30 welded to the negative electrode tab 12b.

[0496] The number of electrode terminals 50 can be one. As an example, as shown in Figure 4, an electrode terminal 50 is installed on the wall of one end of the housing 20 along the first direction Z. A current collector 30 is provided at the end of the electrode assembly 10 along the first direction Z near the electrode terminal 50. The current collector 30 is welded to the tab 12 at that end, and the current collector 30 is also welded to the electrode terminal 50.

[0497] Alternatively, there can be two electrode terminals 50, one a positive electrode terminal 50 and the other a negative electrode terminal 50. The positive and negative electrode terminals 50 can be located at one end of the housing 20 or at both ends of the housing 20. As an example, electrode terminals 50 are provided on the walls of both ends of the housing 20 along the first direction Z, and the electrode assembly 10 has tabs 12 and current collectors 30 at both ends along the first direction Z. In the first direction Z, the tabs 12 at each end are welded to the corresponding current collectors 30, and the electrode terminals 50 are welded to the corresponding current collectors 30.

[0498] The electrode terminal 50 is fixed to the housing 20. Specifically, as shown in Figure 4, the electrode terminal 50 can be disposed on the housing 21 of the housing 20. The electrode terminal 50 can also be disposed on the end cap 22 of the housing 20.

[0499] When there are two electrode terminals 50, the two electrode terminals 50 can be simultaneously disposed on the housing 21; or, the two electrode terminals 50 can be simultaneously disposed on the end cover 22; or, one of the two electrode terminals 50 can be disposed on the housing 21 and the other can be disposed on the end cover 22.

[0500] Electrode terminal 50 is welded to current collector 30, and current collector 30 is welded to electrode lug winding portion 121, so that electrode terminal 50 can be electrically connected to electrode assembly 10.

[0501] The second weld portion 60 refers to the weld mark formed by welding the electrode terminal 50 and the current collector 30. In the radial Y direction, the second weld portion 60 and the first cut-off groove 102 are spaced apart.

[0502] As an example, as shown in Figure 23, on a projection plane perpendicular to the first direction Z, the orthographic projection of the second weld portion 60 is approximately circular and is arranged around the outer periphery of the central hole 101. As another example, there are multiple second weld portions 60. On a projection plane perpendicular to the first direction Z, the orthographic projections of multiple second weld portions 60 are spaced apart along the circumferential direction E, and the orthographic projections of multiple second weld portions 60 together are arranged around the outer periphery of the central hole 101.

[0503] This configuration allows for electrical connection between electrode terminal 50 and electrode assembly 10.

[0504] In some embodiments, please refer to Figures 4, 8, and 23 together, and in conjunction with other figures. On a projection plane perpendicular to the first direction Z, the two ends of the orthographic projection of the second welding portion 60 have a third projection endpoint N1 and a fourth projection endpoint N2, respectively. The third projection endpoint N1 is closer to the winding axis L parallel to the first direction Z than the fourth projection endpoint N2. The area between the third arc line N3, which passes through the third projection endpoint N1 and surrounds the winding axis L, and the fourth arc line N4, which passes through the fourth projection endpoint N2 and surrounds the winding axis L, is the second transverse region N5. At least one tab winding portion 121 includes a plurality of segments 1211 distributed along the winding direction W of the electrode assembly 10, and in the tab winding portion 121, a second cutting groove 106 is provided between any two adjacent segments 1211 along the winding direction W of the electrode assembly 10. At least a portion of the second cut-off grooves 106 form a second group of grooves, in which the orthographic projection of the second groove bottom surface 107 of all the second cut-off grooves 106 is located within the second transverse region N5.

[0505] Understandably, on the projection plane perpendicular to the first direction Z, the third projection endpoint N1 and the fourth projection endpoint N2 are respectively located at the two ends of the radial Y of the orthographic projection of the second welding part 60. The third arc N3 passes through the third projection endpoint N1, and the fourth arc N4 passes through the fourth projection endpoint N2. Both the third arc N3 and the fourth arc N4 are arranged around the outer periphery of the coiling axis L. The third arc N3 and the fourth arc N4 are spaced apart along the radial Y, and the fourth arc N4 surrounds the outer periphery of the third arc N3, so that the third arc N3 and the fourth arc N4 alternately form a second transverse region N5, which is approximately annular. The third arc N3 and the fourth arc N4 are both arranged around the outer periphery of the central hole 101.

[0506] When there are multiple second welding parts 60, on the projection plane perpendicular to the first direction Z, each of the multiple second welding parts 60 has a third projection endpoint N1 and a fourth projection endpoint N2, and the third arc N3 passes through multiple third projection endpoints N1, and the fourth arc N4 passes through multiple fourth projection endpoints N2.

[0507] In this figure, both the third arc N3 and the fourth arc N4 are arc-shaped. As an example, as shown in Figure 23, both the third arc N3 and the fourth arc N4 are circular.

[0508] In the second group of slots, the orthographic projection of the bottom surface 107 of the second slot of all the second cut-off slots 106 lies within the second transverse region N5. This means that on the projection plane perpendicular to the first direction Z, the orthographic projection of the bottom surface 107 of the second slot of each second cut-off slot 106 is substantially within the second transverse region N5. Specifically, on the projection plane perpendicular to the first direction Z, all the second cut-off slots 106 whose orthographic projections of the bottom surface 107 of the second slot are substantially within the second transverse region N5 constitute the second group of slots. It can be understood that the portion of the tab winding portion 121 where the second welding portion 60 is formed is provided with the aforementioned second cut-off slot 106.

[0509] It should be further explained that, on the projection plane perpendicular to the first direction Z, when the orthographic projection of a portion of the second groove bottom surface 107 of a certain second cut-off groove 106 is located within the second transverse region N5, the second groove bottom surface 107 of the second cut-off groove 106 can be defined as being basically located within the second transverse region N5, and the second cut-off groove 106 is defined as one of the second cut-off grooves 106 in the second group of grooves.

[0510] When the second welding portion 60 is formed on the first electrode ear winding portion 121a, the second set of grooves is provided on the first electrode ear winding portion 121a. Alternatively, when the second welding portion 60 is formed on the second electrode ear winding portion 121b, the second set of grooves is provided on the second electrode ear winding portion 121b. When both the first electrode ear winding portion 121a and the second electrode ear winding portion 121b have the second welding portion 60 formed, the second set of grooves can be provided on the first electrode ear winding portion 121a; or on the second electrode ear winding portion 121b; or a portion of the grooves can be provided on the first electrode ear winding portion 121a and the other portion on the second electrode ear winding portion 121b.

[0511] As an example, as shown in Figures 4, 8, and 23, the first weld portion 40 and the second weld portion 60 are spaced apart in the radial direction Y, with the first weld portion 40 located outside the second weld portion 60. Based on this, in the radial direction Y, the first set of grooves is located outside the second set of grooves.

[0512] As an example, as shown in Figures 4 and 8, the second welding part 60 is provided on the first electrode ear winding part 121a, and the second groove group is provided on the first electrode ear winding part 121a.

[0513] In some possible designs, please refer to Figures 4, 8, 17, 18, and 23, in conjunction with other accompanying figures. In the second set of slots, the number of turns of a single second cut-off slot 106 is ≤3.

[0514] The number of turns of a single second cut-off groove 106 refers to the number of layers of the tab layer of a single second cut-off groove 106; it can also refer to the number of turns of the second groove bottom surface 107 of a single second cut-off groove 106 along the winding direction W.

[0515] Specifically, the number of turns of a single second cut-off groove 106 can be 1 turn, 2 turns, 3 turns, or less than 1 turn, more than 1 turn and less than 2 turns, more than 2 turns and less than 3 turns, etc.

[0516] As an example, as shown in Figure 18, the second cut-off groove 106 shown in Figure 18 has less than one turn.

[0517] In some possible designs, please refer to Figures 4, 8, 17, 18, and 23 together with other accompanying drawings. In the second set of slots, the number of second cut-off slots 106 that are radially opposite and interconnected along the Y-axis of the electrode assembly 10 is ≤3.

[0518] Understandably, on the projection plane perpendicular to the first direction Z, the number of consecutive, opposite, and connected second cut-off slots 106 along the radial direction Y is ≤3. On the projection plane perpendicular to the first direction Z, the number of consecutive, opposite, and connected second cut-off slots 106 along the radial direction Y can be 3 or 2; or, any two second cut-off slots 106 are not opposite and connected along the radial direction Y.

[0519] As an example, as shown in Figure 18, the number of second cut-off slots 106 that are radially opposite and connected along the Y direction can be two.

[0520] By adopting the above technical solution, based on the provision of the second cutting groove 106 in the portion of the electrode winding portion 121 where the second welding portion 60 is formed, the deposited layer formed by bending in the portion of the electrode winding portion 121 where the second welding portion 60 is formed will not be too thin due to the provision of the second cutting groove 106. As a result, the portion of the electrode winding portion 121 where the second welding portion 60 is formed can bear the welding penetration of the current collector 30 and the electrode terminal 50, which can improve the problem of laser penetration of the electrode 12 and burning of the diaphragm 2 during the welding process of the current collector 30 and the electrode terminal 50. This can improve the problem of short circuit of the electrode assembly 10 caused by the welding of the current collector 30 and the electrode terminal 50, and reduce the risk of short circuit.

[0521] In some embodiments, please refer to Figures 4, 7, and 8 together, and in conjunction with other figures. In the radial Y direction of the electrode assembly 10, a first welding portion 40 is provided outside the first notch 108.

[0522] By providing the first welding portion 40 on the outer side of the first notch 108 in the radial Y direction of the electrode assembly 10, the deposited layer formed by bending the portion of the tab winding portion 121 where the first welding portion 40 is formed will not be too thin due to the setting of the first notch 108. This allows the portion of the tab winding portion 121 where the first welding portion 40 is formed to bear the welding penetration of the current collector 30 and the tab 12, thereby improving the problem of laser penetration of the tab 12 and burning of the diaphragm 2 during the welding process of the current collector 30 and the tab 12.

[0523] In some embodiments, please refer to Figures 4 and 8 together, and in conjunction with other figures. In the radial Y direction of the electrode assembly 10, a second welding portion 60 is provided outside the first notch groove 108.

[0524] By providing the second welding portion 60 on the outer side of the first notch 108 in the radial Y direction of the electrode assembly 10, the deposited layer formed by bending the portion of the tab winding portion 121 where the second welding portion 60 is formed will not be too thin under the setting of the first notch 108. This allows the portion of the tab winding portion 121 where the second welding portion 60 is formed to bear the welding penetration of the current collector 30 and the electrode terminal 50, thereby improving the problem of laser penetration of the tab 12 and burning of the diaphragm 2 during the welding process of the current collector 30 and the electrode terminal 50.

[0525] The above measures can improve the problem of laser penetration of tab 12 and burning of diaphragm 2 during welding, thereby improving the short circuit problem of electrode assembly 10 and reducing the risk of short circuit.

[0526] In some embodiments, please refer to Figures 4, 7, and 8 together with other figures. In the radial Y direction of the electrode assembly 10, the second notch 1010 is located outside the first weld portion 40.

[0527] By positioning the second notch 1010 on the outer side of the first weld portion 40 in the radial direction Y of the electrode assembly 10, the stacked layer formed by bending the portion of the first weld portion 40 in the tab winding portion 121 will not be too thin due to the setting of the second notch 1010. This allows the portion of the tab winding portion 121 with the first weld portion 40 to bear the welding penetration of the current collector 30 and the tab 12, thereby improving the problem of laser penetration of the tab 12 and burning of the diaphragm 2 during the welding process of the current collector 30 and the tab 12.

[0528] In some embodiments, please refer to Figures 4 and 8 together, and in conjunction with other figures. In the radial Y direction of the electrode assembly 10, the second notch 1010 is located outside the second weld portion 60.

[0529] By positioning the second notch 1010 on the outer side of the second weld portion 60 in the radial Y direction of the electrode assembly 10, the deposited layer formed by bending the portion of the tab winding portion 121 where the second weld portion 60 is formed will not be too thin due to the setting of the second notch 1010. This allows the portion of the tab winding portion 121 where the second weld portion 60 is formed to bear the welding penetration of the current collector 30 and the electrode terminal 50, thereby improving the problem of laser penetration of the tab 12 and burning of the diaphragm 2 during the welding process of the current collector 30 and the electrode terminal 50.

[0530] The above measures can improve the problem of laser penetration of tab 12 and burning of diaphragm 2 during welding, thereby improving the short circuit problem of electrode assembly 10 and reducing the risk of short circuit.

[0531] In some embodiments, please refer to Figures 4, 7, and 8 together, and in conjunction with other figures. Both electrode plates 1 include an electrode plate body 11 and an electrode tab 12, wherein the electrode tab 12 of one electrode plate 1 is a first electrode tab, and the electrode tab 12 of the other electrode plate 1 is a second electrode tab. The first electrode tab and the second electrode tab are respectively disposed at both ends of the electrode assembly 10 along the first direction Z. Both the first electrode tab and the second electrode tab include the aforementioned electrode tab winding portion 121. Along the first direction Z, both ends of the electrode assembly 10 are provided with current collecting members 30, and the current collecting members 30 located at both ends of the electrode assembly 10 are respectively a first current collecting member 30a and a second current collecting member 30b.

[0532] The first electrode can be a positive electrode 12a, and the second electrode can be a negative electrode 12b. Alternatively, the first electrode can be a negative electrode 12b, and the second electrode can be a positive electrode 12a.

[0533] The first current collector 30a is welded to the tab winding portion 121 of the first electrode tab to form the first weld portion 40. The second current collector 30b is welded to the tab winding portion 121 of the second electrode tab to form the first weld portion 40. It can be understood that both the first electrode tab and the second electrode tab have the first weld portion 40 formed thereon.

[0534] It should be noted that the current collectors 30 located at both ends of the electrode assembly 10 are the first current collector 30a and the second current collector 30b, respectively. This means that in the first direction Z, the first current collector 30a and the second current collector 30b are approximately located at both ends of the electrode assembly 10, that is, the first current collector 30a and the second current collector 30b are located at both ends of the main part of the electrode assembly 10. The first current collector 30a and the second current collector 30b can be precisely positioned at both ends of the electrode assembly 10 along the first direction Z. The tabs 12 of the electrode assembly 10 can also partially pass through the first current collector 30a and the second current collector 30b, and be welded to the first current collector 30a and the second current collector 30b, respectively.

[0535] In some embodiments, please refer to Figures 4, 7, and 8 together, and in conjunction with other figures. The housing 20 includes a second end wall 211, a first end wall 221, and a side wall 212. The second end wall 211 and the first end wall 221 are respectively disposed at both ends of the side wall 212 along a first direction Z, and an electrode terminal 50 is provided on the second end wall 211. A first current collector 30a is welded to the electrode winding portion 121 of the first electrode tab and is electrically connected to the electrode terminal 50. A second current collector 30b is welded to the electrode winding portion 121 of the second electrode tab and is electrically connected to the side wall 212.

[0536] The solid wall of the outer casing 20 at one end along the first direction Z is the first end wall 221, and the solid wall of the outer casing 20 at the other end along the first direction Z is the second end wall 211. In the first direction Z, the side wall 212 is disposed between the first end wall 221 and the second end wall 211, and is connected to the first end wall 221 and the second end wall 211.

[0537] The first end wall 221 may be a part of the housing 21; or, as shown in Figures 4 and 7, the first end wall 221 may be at least a part of the end cap 22.

[0538] The second end wall 211 may be at least a portion of the end cap 22; or, as shown in Figures 4 and 8, the second end wall 211 may be a portion of the housing 21.

[0539] As shown in Figures 4, 7 and 8, the sidewall 212 is part of the shell 21 and has electrical conductivity.

[0540] The first end wall 221, the second end wall 211, and the side wall 212 define the internal environment of the cylindrical battery cell 100, and the electrode assembly 10, the first current collector 30a, and the second current collector 30b are all disposed in the internal environment formed by the first end wall 221, the second end wall 211, and the side wall 212.

[0541] The first electrode tab and the first current collector 30a are electrically connected, and the first current collector 30a is electrically connected to the electrode terminal 50, so that the first electrode tab is electrically connected to the electrode terminal 50 through the first current collector 30a. In the first direction Z, the first current collector 30a may be disposed between the first electrode tab and the second end wall 211.

[0542] The second electrode tab is electrically connected to the second current collector 30b, and the second current collector 30b is electrically connected to the side wall 212, so that the second electrode tab is electrically connected to the side wall 212 through the second current collector 30b. In the first direction Z, the second current collector 30b may be disposed between the second electrode tab and the first end wall 221.

[0543] The first current collector 30a is welded to the tab winding portion 121 of the first electrode to achieve electrical connection between the first current collector 30a and the first electrode. The second current collector 30b is welded to the tab winding portion 121 of the second electrode to achieve electrical connection between the second current collector 30b and the second electrode.

[0544] The first current collector 30a and the electrode terminal 50 may be welded, but are not limited to, so as to achieve electrical connection between the first current collector 30a and the electrode terminal 50.

[0545] The second current collector 30b and the side wall 212 can be in direct contact to achieve an electrical connection between them; as an example, the second current collector 30b and the side wall 212 are welded. Alternatively, other intermediate components can be provided between the second current collector 30b and the side wall 212 to achieve an electrical connection between them; as an example, this intermediate component is a first end wall 221, which has conductive properties, and the second current collector 30b is welded to the first end wall 221, and the first end wall 221 is also welded to the side wall 212.

[0546] In some possible designs, the first end wall 221 may be conductive, and the side wall 212 may be electrically connected to the first end wall 221. For example, the side wall 212 may be a part of the housing 21, and the first end wall 221 may be at least a part of the end cap 22. The first end wall 221 and the side wall 212 may be welded, specifically, the first wall 2212 of the first end wall 221 and the side wall 212 may be welded together to make the side wall 212 and the first end wall 221 electrically connected.

[0547] In some possible designs, the second end wall 211 may be conductive, and the side wall 212 may be electrically connected to the second end wall 211. For example, the second end wall 211 and the side wall 212 are two parts of the housing 21, and the second end wall 211 and the housing 21 are integrally formed so that the side wall 212 and the second end wall 211 are electrically connected. The second end wall 211 is insulated from the electrode terminal 50; for example, an insulating component such as insulating glue or plastic is provided between the second end wall 211 and the electrode terminal 50.

[0548] By adopting the above technical solution, at least one of the side wall 212, the first end wall 221, and the second end wall 211 can serve as one current transmission terminal of the cylindrical battery cell 100, and the electrode terminal 50 serves as the other current transmission terminal of the cylindrical battery cell 100. That is, the electrode terminal 50 and the outer casing 20 can serve as two current transmission terminals of the cylindrical battery cell 100.

[0549] When the second end wall 211 and the electrode terminal 50 serve as the two current transmission ends of the cylindrical battery cell 100, the two current transmission ends of the cylindrical battery cell 100 can be located at the same end. This facilitates the assembly process of assembling the cylindrical battery cell 100 into the battery device 1000 and improves the efficiency of assembling multiple cylindrical battery cells 100 into a group.

[0550] In some embodiments, please refer to Figures 4 and 7 together, and in conjunction with other figures. The second current collector 30b is welded to the first end wall 221, and the side wall 212 is electrically connected to the first end wall 221.

[0551] Understandably, both the first end wall 221 and the side wall 212 are conductive. The second current collector 30b can be welded to the first end wall 221, but is not limited to welding, to achieve an electrical connection between the second current collector 30b and the first end wall 221. The side wall 212 can be electrically connected to the first end wall 221 by welding or other methods, thereby achieving an electrical connection between the second current collector 30b and the side wall 212.

[0552] This configuration allows the second current collector 30b to be indirectly electrically connected to the side wall 212 via the first end wall 221.

[0553] In some embodiments, please refer to FIG. 25, and in conjunction with other figures. FIG. 25 is a partial cross-sectional view of a cylindrical battery cell 100 provided in other embodiments of this application. In the radial Y direction of the electrode assembly 10, a protrusion 2121 is formed inwardly on the sidewall 212. The protrusion 2121 and the electrode assembly 10 are distributed along a first direction Z. A second current collector 30b is welded to the side of the protrusion 2121 near the electrode assembly 10, as shown in FIG. 25; or, the second current collector 30b is welded to the side of the protrusion 2121 away from the electrode assembly 10.

[0554] Understandably, the outer peripheral wall of the side wall 212 is provided with a groove 202. The groove 202 is provided so that the side wall 212 protrudes inward along the radial Y direction, thereby forming a protrusion 2121 on the side wall 212.

[0555] The protrusion 2121 can be distributed along the first direction Z with the electrode assembly 10, so that the protrusion 2121 can limit the electrode assembly 10 along the first direction Z. In the first direction Z, the second current collector 30b can be generally disposed between the electrode assembly 10 and the protrusion 2121, and welded to the side of the protrusion 2121 near the electrode assembly 10; or, in the first direction Z, the second current collector 30b can also be generally disposed on the side of the protrusion 2121 away from the electrode assembly 10, and welded to the side of the protrusion 2121 away from the electrode assembly 10.

[0556] This configuration allows the second current collector 30b to be directly electrically connected to the side wall 212.

[0557] In some embodiments, please refer to Figures 4, 7, and 8 together, and in conjunction with other accompanying drawings. The first electrode tab is a positive electrode tab 12a, and the second electrode tab is a negative electrode tab 12b.

[0558] Based on this, electrode terminal 50 is a positive electrode terminal 50, serving as the positive current transmission terminal of the cylindrical battery cell 100; the positive electrode terminal 50 is electrically connected to the first current collector 30a, and the first current collector 30a is welded to the positive electrode tab 12a. At least one of the first end wall 221, the second end wall 211, and the side wall 212 is the negative current transmission terminal of the cylindrical battery cell 100, and the second current collector 30b is welded to the negative electrode tab 12b.

[0559] As an example, both the side wall 212 and the first end wall 221 can be made of steel.

[0560] By adopting the above technical solution, the electrode terminal 50 is a positive electrode terminal 50, and at least one of the first end wall 221, the second end wall 211 and the side wall 212 is a negative current transmission terminal of the cylindrical battery cell 100.

[0561] In some embodiments, please refer to Figures 4 and 7 together, and in conjunction with other figures. A pressure relief portion 22111 is provided on the first end wall 221.

[0562] Understandably, the first end wall 221 includes the aforementioned first wall 2212 and pressure relief mechanism 2211, the pressure relief mechanism 2211 being connected to the first wall 2212, and the pressure relief mechanism 2211 including a pressure relief portion 22111. The first wall 2212 and the pressure relief mechanism 2211 may be integrally formed; alternatively, the first wall 2212 and the pressure relief mechanism 2211 may be separately formed and connected.

[0563] By adopting the above technical solution, the pressure relief part 22111 and the electrode terminal 50 are respectively located at both ends of the housing 20 along the first direction Z, which facilitates the layout of the pressure relief part 22111 and the electrode terminal 50 and helps to improve the efficiency of assembling multiple cylindrical battery cells 100 into a group.

[0564] In some embodiments, please refer to Figures 4, 7, and 24 together, and in conjunction with other figures. Figure 24 is a projected schematic diagram of the current collector 30 and the pressure relief portion 22111 of a cylindrical battery cell 100 provided in some embodiments of this application. Specifically, it is a schematic diagram of the orthographic projection of the pressure relief portion 22111 and the current collector 30 on a projection plane perpendicular to the first direction Z. In Figure 24, the outer contour of the pressure relief portion 22111 is shown as a dashed line. The current collector 30 is provided with an exhaust port 301 extending along the first direction Z, and the exhaust port 301 is disposed opposite to the pressure relief portion 22111 along the first direction Z. The current collector 30 is provided with a plurality of guide portions 32, which are disposed around the outer periphery of the exhaust port 301.

[0565] The flow collecting component 30 is provided with an exhaust through hole 301 extending along the first direction Z, which means that the exhaust through hole 301 penetrates the flow collecting component 30 along the first direction Z.

[0566] The exhaust port 301 and the pressure relief part 22111 are arranged opposite each other along the first direction Z, meaning that at least a portion of the exhaust port 301 and the pressure relief part 22111 are directly opposite each other along the first direction Z. Based on this, when the pressure value inside the housing 20 reaches a threshold and the pressure relief part 22111 opens to form an exhaust passage, the exhaust port 301 and the exhaust passage can be arranged opposite each other and connected along the first direction Z.

[0567] The guide portion 32 refers to the structure on the collector member 30 that guides the collector member 30 to deform and fold near the exhaust port 301, thereby increasing the size of the exhaust port 301. Specifically, the collector member 30 can be split along the guide portion 32 to expand the exhaust area of ​​the exhaust port 301.

[0568] Multiple guide sections 32 are spaced apart along the circumferential direction E and together surround the outer periphery of the exhaust port 301.

[0569] The first collector component 30a may be provided with the aforementioned exhaust hole 301 and guide portion 32. The second collector component 30b may also be provided with the aforementioned exhaust hole 301 and guide portion 32.

[0570] By adopting the above technical solution, during the thermal runaway of the cylindrical battery cell 100, when the pressure inside the casing 20 reaches a threshold, the pressure relief section 22111 can open under the action of air pressure and form an exhaust channel. The guide section 32 can also deform and open towards the pressure relief section 22111 under the action of air pressure, thereby gradually increasing the diameter of the exhaust channel 301. This facilitates the movement of the electrode winding section 14 towards the pressure relief section 22111, allowing it to be released sequentially through the exhaust channel 301 and the exhaust channel to the outside of the casing 20. This configuration helps improve the directional pressure relief efficiency of the cylindrical battery cell 100.

[0571] In some embodiments, please refer to Figures 4, 6, and 20 together, and in conjunction with other figures. On a projection plane perpendicular to the first direction Z, the orthographic projection of the exhaust port 301 is located within the orthographic projection of the pressure relief portion 22111.

[0572] In some embodiments, please refer to Figures 4, 7, and 24 together, and in conjunction with other figures. On a projection plane perpendicular to the first direction Z, along the radial direction Y of the electrode assembly 10, the orthographic projection of the end of the guide portion 32 away from the exhaust port 301 is located outside the outer contour of the orthographic projection of the pressure relief portion 22111. Alternatively, on a projection plane perpendicular to the first direction Z, along the radial direction Y of the electrode assembly 10, the orthographic projection of the end of the guide portion 32 away from the exhaust port 301 coincides with the outer contour of the orthographic projection of the pressure relief portion 22111.

[0573] The pressure relief mechanism 2211 includes a pressure relief part 22111 and a first groove 201, which surrounds the outer periphery of the pressure relief part 22111. On a projection plane perpendicular to the first direction Z, the outer contour of the orthographic projection of the pressure relief part 22111 refers to the inner contour of the orthographic projection of the first groove 201, which is the connection position between the orthographic projection of the pressure relief part 22111 and the orthographic projection of the first groove 201.

[0574] Understandably, the guide portion 32 extends approximately along the radial direction Y. Specifically, in the radial direction Y, the guide portion 32 extends from the exhaust port 301 in a direction away from the exhaust port 301. In the radial direction Y, the end of the guide portion 32 away from the exhaust port 301 is the first edge 321. As shown in FIG24, on a projection plane perpendicular to the first direction Z, the orthographic projection of the first edge 321 is located outside the outer contour of the orthographic projection of the pressure relief portion 22111; or, on a projection plane perpendicular to the first direction Z, the orthographic projection of the first edge 321 coincides with the outer contour of the orthographic projection of the pressure relief portion 22111.

[0575] By adopting the above technical solution, the guide part 32 can be disconnected under air pressure, causing the current collector 30 to deform and open towards the pressure relief part 22111, and the diameter of the exhaust hole 301 can be increased to a greater extent. In this way, during the thermal runaway process of the cylindrical battery cell 100, when the electrode winding part 14 is released to the outside of the outer casing 20 through the exhaust channel formed by the opening of the pressure relief part 22111, the obstruction effect of the current collector 30 on the electrode 1 can be reduced, which helps to improve the efficiency of the electrode 1 in releasing through the exhaust channel, thereby improving the directional pressure relief efficiency of the cylindrical battery cell 100.

[0576] In some embodiments, the guide portion 32 includes a through hole that penetrates the current collecting member 30 along a first direction Z.

[0577] In some embodiments, the guide portion 32 includes a second groove that does not penetrate the collector member 30 along the first direction Z.

[0578] Understandably, the flow collecting component 30 includes a flow collecting body 31 and the aforementioned guide portion 32. The flow collecting body 31 is provided with an exhaust vent 301, and a plurality of guide portions 32 are spaced apart along the circumferential direction E on the flow collecting body 31.

[0579] The current collector 31 can be welded to the tab winding portion 121 of the tab 12 to form the first weld portion 40.

[0580] The current collector 31 can be welded to the electrode terminal 50 to form a second welded part 60.

[0581] Specifically, the collecting body 31 and the guiding part 32 form a second groove, so that the guiding part 32 is a relatively weak part of the collecting member 30, and the structural strength of the guiding part 32 is lower than that of other parts of the collecting member 30. The guiding part 32 may have a groove formed by a notch, which is the second groove.

[0582] By adopting the above technical solution, the guide part 32 can guide the part of the current collector 30 near the exhaust hole 301 to deform and open toward the pressure relief part 22111 during thermal runaway, thereby improving the directional pressure relief effect of the cylindrical battery cell 100.

[0583] In some embodiments, please refer to Figures 4, 7, and 24 together, and in conjunction with other figures. The guide portion 32 extends to the vent hole 301. It will be understood that the guide portion 32 and the wall of the vent hole 301 are engaged.

[0584] In other embodiments, the guide portion 32 is spaced apart from the wall of the exhaust hole 301, and the minimum distance between the guide portion 32 and the wall of the exhaust hole 301 is ≤10mm.

[0585] The minimum distance between the guide part 32 and the wall of the exhaust hole 301 can be 0.1mm, 1mm, 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, etc.

[0586] This configuration allows the guide section 32 to guide the portion of the flow collector 30 near the exhaust port 301 to deform and open toward the pressure relief section 22111 during pressure relief, thereby increasing the exhaust port 301 and achieving a highly efficient directional pressure relief effect.

[0587] In some embodiments, please refer to Figures 4, 7, and 24 together, and in conjunction with other figures. The electrode assembly 10 has a central hole 101 extending along a first direction Z, and an electrode lug 121 is disposed around the outer periphery of the central hole 101. On a projection plane perpendicular to the first direction Z, the orthographic projection of the central hole 101 lies within the orthographic projection of the pressure relief portion 22111. The exhaust port 301 is opposite to and communicates with the central hole 101 along the first direction Z.

[0588] With this configuration, when the pressure inside the housing 20 reaches the threshold and at least part of the pressure relief section 22111 opens to form an exhaust channel, the central hole 101, the exhaust through hole 301, and the exhaust channel are connected sequentially along the first direction Z. This facilitates exhaust and helps improve the directional pressure relief efficiency.

[0589] Please refer to Figure 2 and other accompanying drawings. The battery device 1000 provided in this application embodiment includes a cylindrical battery cell 100. The cylindrical battery cell 100 in this embodiment is the same as the cylindrical battery cell 100 in the above embodiments; please refer to the relevant descriptions of the cylindrical battery cell 100 in the above embodiments for details, which will not be repeated here.

[0590] The battery device 1000 provided in this application adopts the cylindrical battery cell 100 involved in the above embodiments, which enables the battery device 1000 to achieve a highly efficient directional pressure relief effect, thereby helping to improve the reliability and performance of the battery device 1000.

[0591] Please refer to Figure 1 and other accompanying drawings. The electrical device provided in this application embodiment includes a cylindrical battery cell 100 or a battery device 1000. The cylindrical battery cell 100 and battery device 1000 in this embodiment are the same as those in the above embodiments. For details, please refer to the relevant descriptions of the cylindrical battery cell 100 and battery device 1000 in the above embodiments, which will not be repeated here.

[0592] The electrical device provided in this application embodiment, by employing the cylindrical battery cell 100 or battery device 1000 mentioned above, helps to improve the reliability and performance of the electrical device.

[0593] As one embodiment of this application, as shown in Figures 4 to 11, a cylindrical battery cell 100 includes a housing 20 and an electrode assembly 10 disposed within the housing 20. A pressure relief portion 22111 is provided at one end of the housing 20 along a first direction Z. The electrode assembly 10 has a wound structure and a central hole 101 extending along the first direction Z. The electrode assembly 10 includes a positive electrode 1a and a negative electrode 1b. Both the positive electrode 1a and the negative electrode 1b include an electrode body 11 and a tab 12 arranged along the first direction Z. The tab 12 and the electrode body 11 are both disposed around the outer periphery of the central hole 101. The tab 12 of the positive electrode 1a and the tab 12 of the negative electrode 1b are respectively disposed at both ends of the electrode body 11 along the first direction Z. The electrode body 11 is coated with an active material layer 111, while the tab 12 is not coated with an active material layer 111. The electrode lug 12 includes a first electrode lug winding portion 121a, a second electrode lug winding portion 121b, and an electrode lug coil portion 122, all of which are arranged around the outer periphery of the central hole 101. The electrode lug coil portion 122 surrounds the outer periphery of the first electrode lug winding portion 121a and is connected to it. The second electrode lug winding portion 121b surrounds the outer periphery of the electrode lug coil portion 122 and is connected to it. The electrode lug coil portion 122, the first electrode lug winding portion 121a, and the second electrode lug winding portion 121b form a first cutoff groove 102. On a projection plane perpendicular to the first direction Z, the orthographic projection of the root position of the first electrode lug winding portion 121a and the orthographic projection of the central hole 101 are both located within the outer contour of the orthographic projection of the pressure relief portion 22111. The electrode 1 includes a first electrode winding portion 14a, a second electrode winding portion 14b, and an electrode coil portion 15. A first electrode ear winding portion 121a is formed at one end of the first electrode winding portion 14a along a first direction Z. A second electrode ear winding portion 121b is formed at one end of the second electrode winding portion 14b along a first direction Z. An electrode coil portion 122 is formed at one end of the electrode coil portion 15 along a first direction Z. The electrode coil portion 15 surrounds the outer periphery of the first electrode winding portion 14a and is connected to the first electrode winding portion 14a. The second electrode winding portion 14b surrounds the outer periphery of the electrode coil portion 15 and is connected to the electrode coil portion 15. A pressure relief portion 22111 is configured to at least partially open and form an exhaust passage during pressure relief, through which at least a portion of the electrode 1 is released to the outside of the housing 20.

[0594] The above are merely optional 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 scope of the claims of this application.

Claims

1. A cylindrical battery cell, wherein, include: The housing has a pressure relief section at at least one end along a first direction, the pressure relief section being configured to at least partially open during pressure relief; An electrode assembly is at least partially disposed within the housing; the electrode assembly has a wound structure and includes two electrodes with opposite polarities. At least one of the electrode sheets includes an electrode body and an electrode tab arranged along the first direction, the electrode body being coated with an active material layer, and at least a portion of the electrode tab being uncoated with the active material layer; On a projection plane perpendicular to the first direction, at least a portion of the electrode tab's orthographic projection lies within the orthographic projection of the pressure relief portion; The electrode tab includes a plurality of electrode tab winding portions distributed along the winding direction of the electrode assembly. A first cutting groove is provided between two adjacent electrode tab winding portions. The first cutting groove penetrates the end face of the electrode tab away from the electrode body. The first cutting groove is wound at least one turn along the winding direction of the electrode assembly.

2. The cylindrical battery cell according to claim 1, wherein, Among the plurality of electrode winding portions, the innermost electrode winding portion along the winding direction of the electrode assembly is the first electrode winding portion. On a projection plane perpendicular to the first direction, at least a portion of the orthographic projection of the first electrode winding portion is located within the orthographic projection of the pressure relief portion.

3. The cylindrical battery cell according to claim 2, wherein, On a projection plane perpendicular to the first direction, the orthographic projection of the first electrode winding portion lies within the orthographic projection of the pressure relief portion.

4. The cylindrical battery cell according to claim 2 or 3, wherein, The electrode includes a plurality of first cut-off grooves. On a projection plane perpendicular to the first direction, at least a portion of the orthographic projection of the bottom surface of the first groove of the innermost first cut-off groove is located within the orthographic projection of the pressure relief part. Alternatively, the electrode includes a first cut-off groove, and on a projection plane perpendicular to the first direction, at least a portion of the orthographic projection of the bottom surface of the first cut-off groove lies within the orthographic projection of the pressure relief portion.

5. The cylindrical battery cell according to any one of claims 2-4, wherein, The electrode includes a first electrode winding portion, the first electrode lug winding portion being formed at one end of the first electrode winding portion along the first direction, and the pressure relief portion being configured to at least partially open and form an exhaust channel during pressure relief, through which at least a portion of the first electrode winding portion is discharged to the outside of the housing.

6. The cylindrical battery cell according to claim 5, wherein, At least one of the electrode sheets has a winding start end and a winding end end at both ends along the winding direction of the electrode assembly. The winding start end is formed in the winding portion of the first electrode sheet, and on a projection plane perpendicular to the first direction, the orthographic projection of the winding start end is located within the orthographic projection of the pressure relief portion.

7. The cylindrical battery cell according to any one of claims 2-6, wherein, The electrode tab is provided with a central hole extending along the first direction, and each electrode tab winding portion is arranged around the outer periphery of the central hole. On a projection plane perpendicular to the first direction, the orthographic projection of the central hole is located within the orthographic projection of the pressure relief portion.

8. The cylindrical battery cell according to claim 7, wherein, The outer diameter of the electrode assembly is D1, and the diameter of the central hole is D2, where D2 / D1 ∈ [5%, 25%].

9. The cylindrical battery cell according to any one of claims 1-8, wherein, The number of turns of the first cut-off groove along the winding direction of the electrode assembly is ∈ [2, 4].

10. The cylindrical battery cell according to any one of claims 1-9, wherein, Both electrodes include an electrode body and an electrode tab. The electrode tabs of the two electrodes are respectively disposed at both ends of the electrode assembly along the first direction. Each electrode tab includes a plurality of electrode tab winding portions.

11. The cylindrical battery cell according to any one of claims 1-10, wherein, The two electrodes include a positive electrode and a negative electrode, wherein the tabs of the positive electrode and / or the tabs of the negative electrode are not coated with the active material layer.

12. The cylindrical battery cell according to any one of claims 1-11, wherein, The electrode assembly has a winding axis parallel to the first direction, and at least one of the electrode lugs has a bent section at one end in the first direction. The bending section includes a first bending portion that bends relative to the electrode body in a direction close to the winding axis, and / or the bending section includes a second bending portion that bends relative to the electrode body in a direction away from the winding axis.

13. The cylindrical battery cell according to claim 12, wherein, Each of the said tab winding portions has a bent section at one end in the first direction.

14. The cylindrical battery cell according to any one of claims 1-13, wherein, At least one of the electrode sheets has a winding start end and a winding end end at both ends along the winding direction of the electrode assembly; Among the plurality of electrode winding portions, the innermost electrode winding portion is provided with a first notch groove. The first notch groove penetrates the winding start end along the winding direction of the electrode assembly and penetrates the end face of the electrode winding portion away from the electrode body. On a projection plane perpendicular to the first direction, the orthographic projection of the bottom surface of the third groove of the first notch is located within the orthographic projection of the pressure relief part.

15. The cylindrical battery cell according to claim 14, wherein, The cylindrical battery cell further includes a current collector, at least a portion of which is disposed within the housing; The tab winding portion has a winding start section located at one end of the first notch near the electrode body. The bottom surface of the third groove is the end face of the winding start section away from the electrode body. The current collector is welded to the portion of the tab winding portion that extends beyond the bottom surface of the third groove in the direction away from the electrode body, and is not welded to the winding start section.

16. The cylindrical battery cell according to any one of claims 1-15, wherein, At least one of the electrode sheets has a winding start end and a winding end end at both ends along the winding direction of the electrode assembly; Among the plurality of electrode winding portions, the outermost electrode winding portion is provided with a second notch groove, which penetrates the winding end along the winding direction of the electrode assembly and penetrates the end face of the electrode away from the electrode body.

17. The cylindrical battery cell according to claim 16, wherein, The cylindrical battery cell further includes a current collector, at least a portion of which is disposed within the housing; The tab winding portion has a winding end section located at one end of the second notch near the electrode body. The bottom surface of the fourth groove of the second notch is the end face of the winding end section away from the electrode body. The current collector is welded to the portion of the tab winding portion that extends beyond the bottom surface of the fourth groove in the direction away from the electrode body, and is not welded to the winding end section.

18. The cylindrical battery cell according to any one of claims 1-17, wherein, At least one of the electrode lug winding portions includes a plurality of segments distributed along the winding direction of the electrode assembly, and a second cutting groove is provided between any two adjacent segments in the electrode lug winding portion along the winding direction of the electrode assembly. On a projection plane perpendicular to the first direction, the orthographic projection of the bottom surface of at least one second cut-off groove is located within the orthographic projection of the pressure relief section.

19. The cylindrical battery cell according to claim 18, wherein, The plurality of said electrode winding portions include adjacent first electrode winding portions and second electrode winding portions, wherein the second electrode winding portion is disposed on the outside of the first electrode winding portion; The first electrode winding portion includes a plurality of the aforementioned segments. On a projection plane perpendicular to the first direction, in the first electrode winding portion, the orthographic projection of the bottom surface of at least one of the second cut-off grooves is located within the orthographic projection of the pressure relief portion.

20. The cylindrical battery cell according to claim 18 or 19, wherein, The plurality of said electrode winding portions include adjacent first electrode winding portions and second electrode winding portions, wherein the second electrode winding portion is disposed on the outside of the first electrode winding portion; The second electrode winding portion includes a plurality of said segments, wherein the segment closest to the first electrode winding portion is wound at least three times.

21. The cylindrical battery cell according to claim 20, wherein, Of the multiple segments of the second electrode ear winding portion, the segment closest to the first electrode ear winding portion has ≤8 turns.

22. The cylindrical battery cell according to any one of claims 18-21, wherein, The two electrodes include a positive electrode and a negative electrode, wherein the tabs of the positive electrode and / or the tabs of the negative electrode are not coated with the active material layer; in the first direction, the end region of the tab near the electrode body is provided with an insulating layer, and the cut-off piece is located on the side of the insulating layer away from the electrode body.

23. The cylindrical battery cell according to any one of claims 19-22, wherein, At least one of the electrode lug winding portions includes a transition connection portion and the cut piece. The electrode body, the transition connection portion, and the cut piece are arranged sequentially along the first direction. In the electrode lug winding portion, the transition connection portion and any two cut pieces adjacent to each other along the winding direction of the electrode assembly form a second cut-off groove. The bottom surface of the second cut-off groove is formed on one side edge of the transition connection portion used to connect the cut piece.

24. The cylindrical battery cell according to claim 23, wherein, The dimension of one side edge of each of the segments used to connect the transition connection portion in the winding direction of the electrode assembly is H1, and the dimensions of the transition connection portion and the segments in the first direction are H2, where 0.01≤H2 / H1≤0.

3.

25. The cylindrical battery cell according to claim 23 or 24, wherein, The dimension of the transition connection in the first direction is H3, where 0.1mm ≤ H3 ≤ 2mm.

26. The cylindrical battery cell according to any one of claims 18-25, wherein, At least one of the electrode sheets has a winding start end and a winding end end at both ends along the winding direction of the electrode assembly, and among the plurality of electrode tab winding portions, the winding end is formed at the outermost electrode tab winding portion along the winding direction of the electrode assembly. Among the plurality of electrode loop winding portions, along the winding direction of the electrode assembly, the outermost electrode loop winding portion includes a plurality of the segments, and the segment closest to the winding end is wound at least one turn.

27. The cylindrical battery cell according to any one of claims 18-26, wherein, At least one of the electrode winding portions is provided with a plurality of second cut-off grooves, and in the electrode winding portion, each of the second cut-off grooves and each of the cut pieces are arranged alternately along the winding direction of the electrode assembly.

28. The cylindrical battery cell according to any one of claims 18-27, wherein, In the first direction, the size of the truncated piece along the winding direction of the electrode assembly tends to decrease in the direction away from the electrode body.

29. The cylindrical battery cell according to any one of claims 18-28, wherein, The electrode assembly has a winding axis parallel to the first direction, and at least one of the segments has a bent section at one end in the first direction; The bending section includes a first bending portion that bends relative to the electrode body in a direction close to the winding axis, and / or the bending section includes a second bending portion that bends relative to the electrode body in a direction away from the winding axis.

30. The cylindrical battery cell according to claim 29, wherein, Each of the segments has a bent section at one end in the first direction.

31. The cylindrical battery cell according to any one of claims 12, 13, 29, and 30, wherein, The first bending portion is bent radially along the electrode assembly; and / or, the second bending portion is bent radially along the electrode assembly.

32. The cylindrical battery cell according to any one of claims 12, 13, 28-31, wherein, The bending segment includes at least one first bending portion and at least one second bending portion, the first bending portion and the second bending portion being alternately arranged along the first direction.

33. The cylindrical battery cell according to any one of claims 1-32, wherein, The electrode lug also includes an electrode lug portion, which is connected between two adjacent electrode lug winding portions along the winding direction of the electrode assembly, and the electrode lug portion and the two adjacent electrode lug winding portions along the winding direction of the electrode assembly surround to form the first cut-off groove.

34. The cylindrical battery cell according to claim 33, wherein, The cylindrical battery cell further includes a current collector, at least a portion of which is disposed within the housing. The current collector is welded to the tab winding portion to form a first weld portion, and the current collector is not welded to the tab coil portion.

35. The cylindrical battery cell according to claim 34, wherein, On the projection plane perpendicular to the first direction, the two ends of the orthographic projection of the first welded part have a first projection endpoint and a second projection endpoint, respectively. The first projection endpoint is closer to the winding axis parallel to the first direction than the second projection endpoint. The area between the first arc line that passes through the first projection endpoint and surrounds the winding axis and the second arc line that passes through the second projection endpoint and surrounds the winding axis is the first transverse area. At least one of the electrode lug winding portions includes a plurality of segments distributed along the winding direction of the electrode assembly, and in the electrode lug winding portion, a second cutting groove is provided between any two adjacent segments along the winding direction of the electrode assembly, and at least a portion of the second cutting grooves form a first group of grooves, in the first group of grooves, the orthographic projection of the bottom surface of the second groove of all the second cutting grooves is located within the first transverse region; The current collector is welded to the section to form the first welded portion; Wherein, in the first group of slots, the number of turns of a single second cut-off slot is ≤3; and / or, in the first group of slots, the number of second cut-off slots that are radially opposite and connected along the electrode assembly is ≤3.

36. The cylindrical battery cell according to claim 34 or 35, wherein, The cylindrical battery cell also includes electrode terminals fixed to the outer casing, and the electrode terminals are welded to the current collector to form a second welded portion.

37. The cylindrical battery cell according to claim 36, wherein, On the projection plane perpendicular to the first direction, the two ends of the orthographic projection of the second welded part have a third projection endpoint and a fourth projection endpoint, respectively. The third projection endpoint is closer to the winding axis parallel to the first direction than the fourth projection endpoint. The area between the third arc line that passes through the third projection endpoint and surrounds the winding axis and the fourth arc line that passes through the fourth projection endpoint and surrounds the winding axis is the second transverse area. At least one of the electrode lug winding portions includes a plurality of segments distributed along the winding direction of the electrode assembly, and in the electrode lug winding portion, a second cutting groove is provided between any two adjacent segments along the winding direction of the electrode assembly, and at least a portion of the second cutting grooves form a second group of grooves, in the second group of grooves, the orthographic projection of the bottom surface of the second groove of all the second cutting grooves is located within the second transverse region; Wherein, in the second group of slots, the number of turns of a single second cut-off slot is ≤3; and / or, in the second group of slots, the number of second cut-off slots that are radially opposite and interconnected along the electrode assembly is ≤3.

38. The cylindrical battery cell according to claim 36 or 37, wherein, At least one of the electrode sheets has a winding start end and a winding end end at both ends along the winding direction of the electrode assembly; Among the plurality of electrode winding portions, the innermost electrode winding portion is provided with a first notch along the winding direction of the electrode assembly. The first notch penetrates the winding start end along the winding direction of the electrode assembly and penetrates the end face of the electrode opposite to the electrode body. On the projection plane perpendicular to the first direction, the orthographic projection of the bottom surface of the third groove of the first notch is located within the orthographic projection of the pressure relief part; In the radial direction of the electrode assembly, the first weld portion is located outside the first notch groove; and / or, in the radial direction of the electrode assembly, the second weld portion is located outside the first notch groove.

39. The cylindrical battery cell according to any one of claims 36-38, wherein, At least one of the electrode sheets has a winding start end and a winding end end at both ends along the winding direction of the electrode assembly; In the plurality of electrode winding portions, along the winding direction of the electrode assembly, the outermost electrode winding portion is provided with a second notch, the second notch penetrates the winding end along the winding direction of the electrode assembly, and penetrates the end face of the electrode away from the electrode body; In the radial direction of the electrode assembly, the second notch is located outside the first weld portion; and / or, in the radial direction of the electrode assembly, the second notch is located outside the second weld portion.

40. The cylindrical battery cell according to any one of claims 34-39, wherein, Both electrodes include an electrode body and an electrode tab, wherein the electrode tab of one electrode is a first electrode tab and the electrode tab of the other electrode is a second electrode tab. The first electrode tab and the second electrode tab are respectively disposed at both ends of the electrode assembly along the first direction. Both the first electrode tab and the second electrode tab include a plurality of electrode tab winding portions. In the first direction, both ends of the electrode assembly are provided with the current collecting member, and the current collecting members located at both ends of the electrode assembly are respectively the first current collecting member and the second current collecting member; The outer casing includes a second end wall, a first end wall, and a side wall. The second end wall and the first end wall are respectively disposed at both ends of the side wall along the first direction, and electrode terminals are provided on the second end wall. The first current collector is welded to the tab winding portion of the first electrode and electrically connected to the electrode terminal; the second current collector is welded to the tab winding portion of the second electrode and electrically connected to the sidewall.

41. The cylindrical battery cell according to claim 40, wherein, The second current collector is welded to the first end wall, and the side wall is electrically connected to the first end wall.

42. The cylindrical battery cell according to claim 40, wherein, In the radial direction of the electrode assembly, the sidewall protrudes inward to form a protrusion, the protrusion and the electrode assembly are distributed along the first direction, and the second current collector is welded to the side of the protrusion close to or away from the electrode assembly.

43. The cylindrical battery cell according to any one of claims 40-42, wherein, The first electrode is the positive electrode, and the second electrode is the negative electrode.

44. The cylindrical battery cell according to any one of claims 40-43, wherein, The pressure relief section is provided on the first end wall.

45. The cylindrical battery cell according to any one of claims 34-44, wherein, The flow collecting component is provided with an exhaust vent extending along the first direction, and the exhaust vent and the pressure relief part are arranged opposite to each other along the first direction; the flow collecting component is provided with a plurality of guide parts, and the plurality of guide parts are arranged at intervals around the outer periphery of the exhaust vent.

46. ​​The cylindrical battery cell according to claim 45, wherein, The guide portion extends to the exhaust through hole; or, the guide portion is spaced apart from the hole wall of the exhaust through hole, and the minimum distance between the guide portion and the hole wall of the exhaust through hole is less than or equal to 10 mm.

47. The cylindrical battery cell according to claim 45 or 46, wherein, On a projection plane perpendicular to the first direction, along the radial direction of the electrode assembly, the orthographic projection of the end of the guide portion away from the exhaust port is located outside the outer contour of the orthographic projection of the pressure relief portion or coincides with the outer contour of the orthographic projection of the pressure relief portion.

48. The cylindrical battery cell according to any one of claims 45-47, wherein, The guide portion includes a through hole extending through the current collecting member along the first direction; and / or, the guide portion includes a second groove that does not extend through the current collecting member along the first direction.

49. The cylindrical battery cell according to any one of claims 45-48, wherein, The electrode assembly is provided with a central hole extending along the first direction, the electrode lug winding portion is arranged around the outer periphery of the central hole, and the exhaust vent is opposite to and communicates with the central hole along the first direction. On a projection plane perpendicular to the first direction, the orthographic projection of the central hole lies within the orthographic projection of the pressure relief section.

50. The cylindrical battery cell according to any one of claims 1-49, wherein, The housing also includes a first end wall opposite to the electrode assembly along the first direction, the first end wall having a first groove and the pressure relief portion located in the area enclosed by the first groove, the bottom of the first groove having a weak portion, the pressure relief portion being connected to the weak portion, at least a portion of the weak portion being configured to disconnect upon pressure relief to open the pressure relief portion.

51. The cylindrical battery cell according to any one of claims 1-49, wherein, The housing further includes a first wall and a pressure relief mechanism. The first wall is disposed opposite to the electrode assembly along the first direction. The first wall is fixedly connected to the pressure relief mechanism. The pressure relief mechanism has a first groove and a pressure relief portion located in the area enclosed by the first groove. The bottom of the first groove has a weak portion. The pressure relief portion is connected to the weak portion. At least a portion of the weak portion is configured to be disconnected during pressure relief to open the pressure relief portion.

52. The cylindrical battery cell according to any one of claims 1-51, wherein, On a projection plane perpendicular to the first direction, the outer contour of the orthographic projection of the pressure relief part is circular.

53. A battery device, wherein, Includes the cylindrical battery cell according to any one of claims 1-52.

54. An electrical appliance, wherein, It includes a cylindrical battery cell according to any one of claims 1-52; or, it includes a battery device according to claim 53.

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